U.S. patent application number 15/811255 was filed with the patent office on 2018-03-08 for enhanced rts/cts enablement and detection.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Gwendolyn Denise BARRIAC, George CHERIAN, Simone MERLIN, Yan ZHOU.
Application Number | 20180070260 15/811255 |
Document ID | / |
Family ID | 55456223 |
Filed Date | 2018-03-08 |
United States Patent
Application |
20180070260 |
Kind Code |
A1 |
ZHOU; Yan ; et al. |
March 8, 2018 |
ENHANCED RTS/CTS ENABLEMENT AND DETECTION
Abstract
In an aspect of the disclosure, a method, a computer-readable
medium, and an apparatus are provided. The apparatus may be an AP
that requests a plurality of STAs to jointly enable and disable an
MRP based on at least one of that each STA of the STAs has uplink
traffic with the AP or that each STA of a subset of the STAs has a
hidden node. The AP receives, from the STAs, information indicating
a communication metric while jointly enabling or disabling the MRP.
The AP determines, based on the received information indicating the
communication metric, whether the joint enablement of the medium
reserving procedure improves communication for the plurality of
STAs. The AP requests the STAs to jointly enable the medium
reserving procedure for subsequent communication when the joint
enablement of the medium reserving procedure improves communication
for the plurality of STAs.
Inventors: |
ZHOU; Yan; (San Diego,
CA) ; BARRIAC; Gwendolyn Denise; (Encinitas, CA)
; MERLIN; Simone; (Solana Beach, CA) ; CHERIAN;
George; (San Diego, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
55456223 |
Appl. No.: |
15/811255 |
Filed: |
November 13, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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14852434 |
Sep 11, 2015 |
9838900 |
|
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15811255 |
|
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62050691 |
Sep 15, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 84/12 20130101;
H04W 74/00 20130101; H04W 24/10 20130101; H04W 74/0816 20130101;
H04W 28/26 20130101 |
International
Class: |
H04W 24/10 20090101
H04W024/10; H04W 74/08 20090101 H04W074/08; H04W 28/26 20090101
H04W028/26 |
Claims
1. A method of wireless communication of a first station (STA),
comprising: sending, in accordance with a Request-to-Send
(RTS)/Clear-to-Send (CTS) procedure, one or more RTS messages to a
second STA; receiving zero or more CTS messages in response to the
one or more RTS messages from the second STA; determining a
response rate based on the one or more RTS messages and the zero or
more CTS messages; and sending a first request to the second STA
when the response rate meets a first threshold, the first request
requesting the second STA to announce receiver availability for
receiving data transmission.
2. The method of claim 1, wherein the first request includes a
channel load at the first STA.
3. The method of claim 1, wherein the one or more RTS messages
include a first number of RTS messages, wherein the zero or more
CTS messages include a second number of CTS messages, and wherein
the response rate is determined based on the first number and the
second number.
4. The method of claim 1, further comprising: receiving, from the
second STA, a first confirmation indicating that the second STA
implements a polling procedure; receiving a polling message in
accordance with the polling procedure, wherein the polling message
indicates that the second STA is available for data transmission;
and transmitting data to the second STA in response to the polling
message.
5. The method of claim 4, further comprising determining whether
the first STA is available for data transmission to the second STA
before transmitting the data to the second STA.
6. The method of claim 4, further comprising: receiving, from the
second STA, a second request requesting the first STA to implement
the RTS/CTS procedure, wherein the second request includes a
channel load at the second STA; determining that a difference
between the channel load at the second STA and a channel load at
the first STA meets a second threshold; and transmitting, to the
second STA, a second confirmation indicating that the first STA
implements the RTS/CTS procedure.
7. The method of claim 6, wherein the second threshold is based on
the channel load at the first STA being greater than the channel
load at the second STA.
8. The method of claim 6, wherein one or more of the first
confirmation or the second confirmation are embedded in an
information element of a management frame or a data frame.
9. An apparatus for wireless communication, comprising: means for
sending, in accordance with a Request-to-Send (RTS)/Clear-to-Send
(CTS) procedure, one or more RTS messages to a second STA; means
for receiving zero or more CTS messages in response to the one or
more RTS messages from the second STA; means for determining a
response rate based on the one or more RTS messages and the zero or
more CTS messages; and means for sending a first request to the
second STA when the response rate meets a first threshold, the
first request requesting the second STA to announce receiver
availability for receiving data transmission.
10. The apparatus of claim 9, wherein the first request includes a
channel load at the apparatus.
11. The apparatus of claim 9, wherein the one or more RTS messages
include a first number of RTS messages, wherein the zero or more
CTS messages include a second number of CTS messages, and wherein
the response rate is determined based on the first number and the
second number.
12. The apparatus of claim 9, further comprising: means for
receiving, from the second STA, a first confirmation indicating
that the second STA implements a polling procedure; means for
receiving a polling message in accordance with the polling
procedure, wherein the polling message indicates that the second
STA is available for data transmission; and means for transmitting
data to the second STA in response to the polling message.
13. The apparatus of claim 12, further comprising means for
determining whether the apparatus is available for data
transmission to the second STA before transmitting the data to the
second STA.
14. The apparatus of claim 12, further comprising: means for
receiving, from the second STA, a second request requesting the
apparatus to implement the RTS/CTS procedure, wherein the second
request includes a channel load at the second STA; means for
determining that a difference between the channel load at the
second STA and a channel load at the apparatus meets a second
threshold; and means for transmitting, to the second STA, a second
confirmation indicating that the apparatus implements the RTS/CTS
procedure.
15. The apparatus of claim 14, wherein the second threshold is
based on the channel load at the frist STA being greater than the
channel load at the second STA.
16. The apparatus of claim 14, wherein one or more of the first
confirmation or the second confirmation are embedded in an
information element of a management frame or a data frame.
17. An apparatus for wireless communication, the apparatus being a
first station (STA), comprising: a memory; and at least one
processor coupled to the memory and configured to: send, in
accordance with a Request-to-Send (RTS)/Clear-to-Send (CTS)
procedure, one or more RTS messages to a second STA; receive zero
or more CTS messages in response to the one or more RTS messages
from the second STA; determine a response rate based on the one or
more RTS messages and the zero or more CTS messages; and send a
first request to the second STA when the response rate meets a
first threshold, the first request requesting the second STA to
announce receiver availability for receiving data transmission.
18. The apparatus of claim 17, wherein the first request includes a
channel load at the apparatus.
19. The apparatus of claim 17, wherein the one or more RTS messages
include a first number of RTS messages, wherein the zero or more
CTS messages include a second number of CTS messages, and wherein
the response rate is determined based on the first number and the
second number.
20. The apparatus of claim 17, wherein the at least one processor
is further configured to: receive, from the second STA, a first
confirmation indicating that the second STA implements a polling
procedure; receive a polling message in accordance with the polling
procedure, wherein the polling message indicates that the second
STA is available for data transmission; and transmit data to the
second STA in response to the polling message.
21. The apparatus of claim 20, wherein the at least one processor
is further configured to determine whether the apparatus is
available for data transmission to the second STA before
transmitting the data to the second STA.
22. The apparatus of claim 20, wherein the at least one processor
is further configured to: receive, from the second STA, a second
request requesting the apparatus to implement the RTS/CTS
procedure, wherein the second request includes a channel load at
the second STA; determine that a difference between the channel
load at the second STA and a channel load at the apparatus meets a
second threshold; and transmit, to the second STA, a second
confirmation indicating that the apparatus implements the RTS/CTS
procedure.
23. The apparatus of claim 22, wherein the second threshold is
based on the channel load at the apparatus being greater than the
channel load at the second STA.
24. A computer-readable medium storing computer executable code for
a first station (STA), comprising code for: sending, in accordance
with a Request-to-Send (RTS)/Clear-to-Send (CTS) procedure, one or
more RTS messages to a second STA; receiving zero or more CTS
messages in response to the one or more RTS messages from the
second STA; determining a response rate based on the one or more
RTS messages and the zero or more CTS messages; and sending a first
request to the second STA when the response rate meets a first
threshold, the first request requesting the second STA to announce
receiver availability for receiving data transmission.
25. The computer-readable medium of claim 24, wherein the first
request includes a channel load at the first STA.
26. The computer-readable medium of claim 24, wherein the one or
more RTS messages include a first number of RTS messages, wherein
the zero or more CTS messages include a second number of CTS
messages, and wherein the response rate is determined based on the
first number and the second number.
27. The computer-readable medium of claim 24, further comprising
code for: receiving, from the second STA, a first confirmation
indicating that the second STA implements a polling procedure;
receiving a polling message in accordance with the polling
procedure, wherein the polling message indicates that the second
STA is available for data transmission; and transmitting data to
the second STA in response to the polling message.
28. The computer-readable medium of claim 27, further comprising
code for determining whether the first STA is available for data
transmission to the second STA before transmitting the data to the
second STA.
29. The computer-readable medium of claim 27, further comprising
code for : receiving, from the second STA, a second request
requesting the first STA to implement the RTS/CTS procedure,
wherein the second request includes a channel load at the second
STA; determining that a difference between the channel load at the
second STA and a channel load at the first STA meets a second
threshold; and transmitting, to the second STA, a second
confirmation indicating that the first STA implements the RTS/CTS
procedure.
30. The computer-readable medium of claim 29, wherein the second
threshold is based on the channel load at the first STA being
greater than the channel load at the second STA.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application is a divisional of U.S. patent application
Ser. No. 14/852,434, entitled "ENHANCED RTS/CTS ENABLEMENT AND
DETECTION" and filed on Sep. 11, 2015, which claims the benefit of
U.S. Provisional Application Ser. No. 62/050,691, entitled
"ENHANCED RTS/CTS ENABLEMENT AND DETECTION" and filed on Sep. 15,
2014, which are expressly incorporated by reference herein in their
entirety.
BACKGROUND
Field
[0002] The present disclosure relates generally to communication
systems, and more particularly, to techniques of enhanced
Request-to-Send (RTS)/Clear-to-Send (CTS) enablement and
detection.
Background
[0003] In many telecommunication systems, communications networks
are used to exchange messages among several interacting
spatially-separated devices. Networks may be classified according
to geographic scope, which could be, for example, a metropolitan
area, a local area, or a personal area. Such networks would be
designated respectively as a wide area network (WAN), metropolitan
area network (MAN), local area network (LAN), wireless local area
network (WLAN), or personal area network (PAN). Networks also
differ according to the switching/routing technique used to
interconnect the various network nodes and devices (e.g., circuit
switching vs. packet switching), the type of physical media
employed for transmission (e.g., wired vs. wireless), and the set
of communication protocols used (e.g., Internet protocol suite,
Synchronous Optical Networking (SONET), Ethernet, etc.).
[0004] Wireless networks are often preferred when the network
elements are mobile and thus have dynamic connectivity needs, or if
the network architecture is formed in an ad hoc, rather than fixed,
topology. Wireless networks employ intangible physical media in an
unguided propagation mode using electromagnetic waves in the radio,
microwave, infra-red, optical, etc., frequency bands. Wireless
networks advantageously facilitate user mobility and rapid field
deployment when compared to fixed wired networks.
SUMMARY
[0005] The systems, methods, computer program products, and devices
of the invention each have several aspects, no single one of which
is solely responsible for its desirable attributes. Without
limiting the scope of this invention as expressed by the claims
which follow, some features will now be discussed briefly. After
considering this discussion, and particularly after reading the
section entitled "Detailed Description" one will understand how the
features of this invention provide advantages that include improved
narrowband channel selection for devices in a wireless network
[0006] In an aspect of the disclosure, a method, a
computer-readable medium, and an apparatus are provided. The
apparatus may be an AP. The AP requests a plurality of STAs to
jointly enable and disable a medium reserving procedure (MRP) for
communication based on at least one of that each STA of the
plurality of STAs has uplink traffic with the AP or that each STA
of a subset of STAs of the plurality of STAs has a hidden node that
transmits data to the AP and disrupts a communication between the
AP and the each STA. The AP receives, from the plurality of STAs,
information indicating a communication metric while jointly
enabling or disabling the medium reserving procedure for
communication. The AP determines, based on the received information
indicating the communication metric, whether the joint enablement
of the medium reserving procedure improves communication for the
plurality of STAs. The AP requests the plurality of STAs to jointly
enable the medium reserving procedure for subsequent communication
when the joint enablement of the medium reserving procedure
improves communication for the plurality of STAs.
[0007] In another aspect of the disclosure, a method, a
computer-readable medium, and an apparatus are provided. The
apparatus may be a first STA. The first STA sends, in accordance
with an RTS/CTS procedure, one or more RTS messages to a second
STA. The first STA receives zero or more CTS messages in response
to the RTS messages from the second STA. The first STA determines a
response rate based on the RTS messages and the CTS messages. The
first STA sends a first switching request to the second STA when
the response rate meets a threshold. The first switching request
requests the second STA to implement a polling procedure. The
polling procedure announces receiver availability for receiving
data transmission.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 shows an example wireless communication system in
which aspects of the present disclosure may be employed.
[0009] FIG. 2 shows a functional block diagram of an example
wireless device that may be employed within the wireless
communication system of FIG. 1.
[0010] FIG. 3 is a diagram illustrating wireless devices in a
wireless network.
[0011] FIG. 4 is a diagram illustrating signal communication among
wireless devices having full buffer neighboring devices in a
wireless network.
[0012] FIG. 5 is a diagram illustrating signal communication among
wireless devices implementing an RTS/CTS enablement technique in a
wireless network.
[0013] FIG. 6 is a diagram illustrating signal communication among
wireless devices in a wireless network.
[0014] FIG. 7 is a diagram illustrating formats of information
elements used to signal joint enablement of the RTS/CTS
procedure.
[0015] FIG. 8 is a diagram illustrating signal communication among
wireless devices in a wireless network.
[0016] FIG. 9 is a diagram illustrating wireless devices in a
wireless network.
[0017] FIG. 10 is a diagram illustrating signal communication among
wireless devices in a wireless network.
[0018] FIG. 11 is a flow chart of an exemplary method of joint
enablement of a medium reserving procedure.
[0019] FIG. 12 is a flow chart of an exemplary method for
determining an improvement of a communication metric.
[0020] FIG. 13 is a flow chart of an exemplary method for switching
from an RTS/CTS procedure to a polling procedure.
[0021] FIG. 14 is a flowchart of a first method of wireless
communication for jointly enabling a medium reserving
procedure.
[0022] FIG. 15 is a flowchart of a method of wireless communication
for determining existence of a hidden node.
[0023] FIG. 16 is a flowchart of a method of wireless communication
for determining interference.
[0024] FIG. 17 is a flowchart of a method of wireless communication
for jointly enabling a medium reserving procedure at all receiving
stations.
[0025] FIG. 18 is a flowchart of a first method of wireless
communication for evaluating whether using a medium reserving
procedure can improve throughput.
[0026] FIG. 19 is a flowchart of a second method of wireless
communication for determining existence of a hidden node.
[0027] FIG. 20 is a flowchart of a method of wireless communication
for jointly enabling a medium reserving procedure at a station.
[0028] FIG. 21 is a flowchart of a method of wireless communication
for determining whether to enable a medium reserving procedure
based on signal metrics.
[0029] FIG. 22 is a flowchart of a method of wireless communication
for determining whether to enable a medium reserving procedure
based on data units that have not been correctly received at a
station.
[0030] FIG. 23 is a flowchart of a method of wireless communication
for determining whether to enable a medium reserving procedure
based on PERs.
[0031] FIG. 24 is a flowchart of a second method of wireless
communication for evaluating whether using a medium reserving
procedure can improve throughput.
[0032] FIG. 25 is a flowchart of a method of wireless communication
for using an enhanced medium reserving procedure.
[0033] FIG. 26 is a flowchart of a method of wireless communication
for transmitting requests/responses of a medium reserving procedure
at different data rates.
[0034] FIG. 27 is a flowchart of a method of wireless communication
for initiating a switching procedure.
[0035] FIG. 28 is a flowchart of a method of wireless communication
for responding to a switching procedure.
[0036] FIG. 29 is a conceptual data flow diagram illustrating the
data flow between different components/means in an exemplary
apparatus.
[0037] FIG. 30 is a conceptual data flow diagram illustrating the
data flow between different components/means in another exemplary
apparatus.
[0038] FIG. 31 is a functional block diagram of an example wireless
communication device.
DETAILED DESCRIPTION
[0039] Various aspects of the novel systems, apparatuses,
computer-readable media, and methods are described more fully
hereinafter with reference to the accompanying drawings. This
disclosure may, however, be embodied in many different forms and
should not be construed as limited to any specific structure or
function presented throughout this disclosure. Rather, these
aspects are provided so that this disclosure will be thorough and
complete, and will fully convey the scope of the disclosure to
those skilled in the art. Based on the teachings herein one skilled
in the art should appreciate that the scope of the disclosure is
intended to cover any aspect of the novel systems, apparatuses,
computer-readable media, and methods disclosed herein, whether
implemented independently of, or combined with, any other aspect of
the invention. For example, an apparatus may be implemented or a
method may be practiced using any number of the aspects set forth
herein. In addition, the scope of the invention is intended to
cover such an apparatus or method which is practiced using other
structure, functionality, or structure and functionality in
addition to or other than the various aspects of the invention set
forth herein. It should be understood that any aspect disclosed
herein may be embodied by one or more elements of a claim.
[0040] Although particular aspects are described herein, many
variations and permutations of these aspects fall within the scope
of the disclosure. Although some benefits and advantages of the
preferred aspects are mentioned, the scope of the disclosure is not
intended to be limited to particular benefits, uses, or objectives.
Rather, aspects of the disclosure are intended to be broadly
applicable to different wireless technologies, system
configurations, networks, and transmission protocols, some of which
are illustrated by way of example in the figures and in the
following description of the preferred aspects. The detailed
description and drawings are merely illustrative of the disclosure
rather than limiting, the scope of the disclosure being defined by
the appended claims and equivalents thereof.
[0041] Popular wireless network technologies may include various
types of wireless local area networks (WLANs). A WLAN may be used
to interconnect nearby devices together, employing widely used
networking protocols. The various aspects described herein may
apply to any communication standard, such as a wireless
protocol.
[0042] In some aspects, wireless signals may be transmitted
according to an 802.11 protocol using orthogonal frequency-division
multiplexing (OFDM), direct-sequence spread spectrum (DSSS)
communications, a combination of OFDM and DSSS communications, or
other schemes. Implementations of the 802.11 protocol may be used
for sensors, metering, and smart grid networks. Advantageously,
aspects of certain devices implementing the 802.11 protocol may
consume less power than devices implementing other wireless
protocols, and/or may be used to transmit wireless signals across a
relatively long range, for example about one kilometer or
longer.
[0043] In some implementations, a WLAN includes various devices
which are the components that access the wireless network. For
example, there may be two types of devices: access points (APs) and
clients (also referred to as stations or "STAs"). In general, an AP
may serve as a hub or base station for the WLAN and a STA serves as
a user of the WLAN. For example, a STA may be a laptop computer, a
personal digital assistant (PDA), a mobile phone, etc. In an
example, a STA connects to an AP via a WiFi (e.g., IEEE 802.11
protocol) compliant wireless link to obtain general connectivity to
the Internet or to other wide area networks. In some
implementations a STA may also be used as an AP.
[0044] An access point may also comprise, be implemented as, or
known as a NodeB, Radio Network Controller (RNC), eNodeB, Base
Station Controller (BSC), Base Transceiver Station (BTS), Base
Station (BS), Transceiver Function (TF), Radio Router, Radio
Transceiver, connection point, or some other terminology.
[0045] A station may also comprise, be implemented as, or known as
an access terminal (AT), a subscriber station, a subscriber unit, a
mobile station, a remote station, a remote terminal, a user
terminal, a user agent, a user device, a user equipment, or some
other terminology. In some implementations an access terminal may
comprise a cellular telephone, a cordless telephone, a Session
Initiation Protocol (SIP) phone, a wireless local loop (WLL)
station, a personal digital assistant (PDA), a handheld device
having wireless connection capability, or some other suitable
processing device connected to a wireless modem. Accordingly, one
or more aspects taught herein may be incorporated into a phone
(e.g., a cellular phone or smartphone), a computer (e.g., a
laptop), a portable communication device, a headset, a portable
computing device (e.g., a personal data assistant), an
entertainment device (e.g., a music or video device, or a satellite
radio), a gaming device or system, a global positioning system
device, or any other suitable device that is configured to
communicate via a wireless medium.
[0046] In an aspect, MIMO schemes may be used for wide area WLAN
(e.g., WiFi) connectivity. MIMO exploits a radio-wave
characteristic called multipath. In multipath, transmitted data may
bounce off objects (e.g., walls, doors, furniture), reaching the
receiving antenna multiple times through different routes and at
different times. A WLAN device that employs MIMO will split a data
stream into multiple parts, called spatial streams, and transmit
each spatial stream through separate antennas to corresponding
antennas on a receiving WLAN device.
[0047] The term "associate," or "association," or any variant
thereof should be given the broadest meaning possible within the
context of the present disclosure. By way of example, when a first
apparatus associates with a second apparatus, it should be
understood that the two apparatus may be directly associated or
intermediate apparatuses may be present. For purposes of brevity,
the process for establishing an association between two apparatuses
will be described using a handshake protocol that requires an
"association request" by one of the apparatus followed by an
"association response" by the other apparatus. It will be
understood by those skilled in the art the handshake protocol may
require other signaling, such as by way of example, signaling to
provide authentication.
[0048] Any reference to an element herein using a designation such
as "first," "second," and so forth does not generally limit the
quantity or order of those elements. Rather, these designations are
used herein as a convenient method of distinguishing between two or
more elements or instances of an element. Thus, a reference to
first and second elements does not mean that only two elements can
be employed, or that the first element must precede the second
element. In addition, a phrase referring to "at least one of" a
list of items refers to any combination of those items, including
single members. As an example, "at least one of: A, B, or C" is
intended to cover: A, or B, or C, or any combination thereof (e.g.,
A-B, A-C, B-C, and A-B-C).
[0049] As discussed above, certain devices described herein may
implement the 802.11 standard, for example. Such devices, whether
used as a STA or AP or other device, may be used for smart metering
or in a smart grid network. Such devices may provide sensor
applications or be used in home automation. The devices may instead
or in addition be used in a healthcare context, for example for
personal healthcare. They may also be used for surveillance, to
enable extended-range Internet connectivity (e.g. for use with
hotspots), or to implement machine-to-machine communications.
[0050] Certain of the devices described herein may further
implement Multiple Input Multiple Output (MIMO) technology and be
implemented as part of the 802.11 standard. A MIMO system employs
multiple (NT) transmit antennas and multiple (NR) receive antennas
for data transmission. A MIMO channel formed by the NT transmit and
NR receive antennas may be decomposed into N.sub.S independent
channels, which are also referred to as spatial channels or
streams, where N.sub.S.ltoreq.min{N.sub.T, N.sub.R} Each of the
N.sub.S independent channels corresponds to a dimension. The MIMO
system can provide improved performance (e.g., higher throughput
and/or greater reliability) if the additional dimensionalities
created by the multiple transmit and receive antennas are
utilized.
[0051] FIG. 1 shows an example wireless communication system 100 in
which aspects of the present disclosure may be employed. The
wireless communication system 100 may operate pursuant to a
wireless standard, for example the 802.11 standard. The wireless
communication system 100 may include an AP 104, which communicates
with STAs (e.g., STAs 112, 114, 116, and 118).
[0052] A variety of processes and methods may be used for
transmissions in the wireless communication system 100 between the
AP 104 and the STAs. For example, signals may be sent and received
between the AP 104 and the STAs in accordance with OFDM/OFDMA
techniques. If this is the case, the wireless communication system
100 may be referred to as an OFDM/OFDMA system. Alternatively,
signals may be sent and received between the AP 104 and the STAs in
accordance with CDMA techniques. If this is the case, the wireless
communication system 100 may be referred to as a CDMA system.
[0053] A communication link that facilitates transmission from the
AP 104 to one or more of the STAs may be referred to as a downlink
(DL) 108, and a communication link that facilitates transmission
from one or more of the STAs to the AP 104 may be referred to as an
uplink (UL) 110. Alternatively, a downlink 108 may be referred to
as a forward link or a forward channel, and an uplink 110 may be
referred to as a reverse link or a reverse channel. In some
aspects, DL communications may include unicast or multicast traffic
indications.
[0054] The AP 104 may suppress adjacent channel interference (ACI)
in some aspects so that the AP 104 may receive UL communications on
more than one channel simultaneously without causing significant
analog-to-digital conversion (ADC) clipping noise. The AP 104 may
improve suppression of ACI, for example, by having separate finite
impulse response (FIR) filters for each channel or having a longer
ADC backoff period with increased bit widths.
[0055] The AP 104 may act as a base station and provide wireless
communication coverage in a basic service area (BSA) 102. A BSA
(e.g., the BSA 102) is the coverage area of an AP (e.g., the AP
104). The AP 104 along with the STAs associated with the AP 104 and
that use the AP 104 for communication may be referred to as a basic
service set (BSS). It should be noted that the wireless
communication system 100 may not have a central AP (e.g., AP 104),
but rather may function as a peer-to-peer network between the STAs.
Accordingly, the functions of the AP 104 described herein may
alternatively be performed by one or more of the STAs.
[0056] The AP 104 may transmit on one or more channels (e.g.,
multiple narrowband channels, each channel including a frequency
bandwidth) a beacon signal (or simply a "beacon"), via a
communication link such as the downlink 108, to other nodes (STAs)
of the wireless communication system 100, which may help the other
nodes (STAs) to synchronize their timing with the AP 104, or which
may provide other information or functionality. Such beacons may be
transmitted periodically. In one aspect, the period between
successive transmissions may be referred to as a superframe.
Transmission of a beacon may be divided into a number of groups or
intervals. In one aspect, the beacon may include, but is not
limited to, such information as timestamp information to set a
common clock, a peer-to-peer network identifier, a device
identifier, capability information, a superframe duration,
transmission direction information, reception direction
information, a neighbor list, and/or an extended neighbor list,
some of which are described in additional detail below. Thus, a
beacon may include information that is both common (e.g., shared)
amongst several devices and specific to a given device.
[0057] In some aspects, a STA (e.g., STA 114) may be required to
associate with the AP 104 in order to send communications to and/or
to receive communications from the AP 104. In one aspect,
information for associating is included in a beacon broadcast by
the AP 104. To receive such a beacon, the STA 114 may, for example,
perform a broad coverage search over a coverage region. A search
may also be performed by the STA 114 by sweeping a coverage region
in a lighthouse fashion, for example. After receiving the
information for associating, the STA 114 may transmit a reference
signal, such as an association probe or request, to the AP 104. In
some aspects, the AP 104 may use backhaul services, for example, to
communicate with a larger network, such as the Internet or a public
switched telephone network (PSTN).
[0058] In an aspect, the AP 104 may include one or more components
for performing various functions. The AP 104 may include a joint
MRP enablement/disablement component 124. The joint MRP
enablement/disablement component 124 may control a process of
requesting a plurality of STAs to jointly enable and disable a
medium reserving procedure for communication based on at least one
of that each STA of the plurality of STAs has uplink traffic with
the AP or that each STA of a subset of STAs of the plurality of
STAs has a hidden node that transmits data to the AP and disrupts a
communication between the AP and the each STA. The joint MRP
enablement/disablement component 124 may control a process of
receiving, from the plurality of STAs, information indicating a
communication metric while jointly enabling or disabling the medium
reserving procedure for communication. The joint MRP
enablement/disablement component 124 may control a process of
determining, based on the received information indicating the
communication metric, whether the joint enablement of the medium
reserving procedure improves communication for the plurality of
STAs. The joint MRP enablement/disablement component 124 may
control a process of requesting the plurality of STAs to jointly
enable the medium reserving procedure for subsequent communication
when the joint enablement of the medium reserving procedure
improves communication for the plurality of STAs.
[0059] In another aspect, the STA 114 may include one or more
components for performing various functions. For example, the STA
114 may include an MRP/polling enablement component 126. The
MRP/polling enablement component 126 may control a process of
sending, in accordance with an RTS/CTS procedure, one or more RTS
messages to a second STA. The MRP/polling enablement component 126
may control a process of receiving zero or more CTS messages in
response to the RTS messages from the second STA. The MRP/polling
enablement component 126 may control a process of determining a
response rate based on the RTS messages and the CTS messages. The
MRP/polling enablement component 126 may control a process of
sending a first switching request to the second STA when the
response rate meets a threshold, the first switching request
requesting the second STA to implement a polling procedure, the
polling procedure announcing receiver availability for receiving
data transmission.
[0060] FIG. 2 is a functional block diagram of a wireless device
202 that may be employed within the wireless communication system
100 of FIG. 1. The wireless device 202 is an example of a device
that may be configured to implement the various methods described
herein. For example, the wireless device 202 may comprise the AP
104 or any one of the STAs 112, 114, 116, or 118.
[0061] The wireless device 202 may include a processor 204 which
controls operation of the wireless device 202. The processor 204
may also be referred to as a central processing unit (CPU). Memory
206, which may include both read-only memory (ROM) and random
access memory (RAM), may provide instructions and data to the
processor 204. A portion of the memory 206 may also include
non-volatile random access memory (NVRAM). The processor 204
typically performs logical and arithmetic operations based on
program instructions stored within the memory 206. The instructions
in the memory 206 may be executable (by the processor 204, for
example) to implement the methods described herein.
[0062] The processor 204 may comprise or be a component of a
processing system implemented with one or more processors. The one
or more processors may be implemented with any combination of
general-purpose microprocessors, microcontrollers, digital signal
processors (DSPs), field programmable gate array (FPGAs),
programmable logic devices (PLDs), controllers, state machines,
gated logic, discrete hardware components, dedicated hardware
finite state machines, or any other suitable entities that can
perform calculations or other manipulations of information.
[0063] The processing system may also include machine-readable
media for storing software. Software shall be construed broadly to
mean any type of instructions, whether referred to as software,
firmware, middleware, microcode, hardware description language, or
otherwise. Instructions may include code (e.g., in source code
format, binary code format, executable code format, or any other
suitable format of code). The instructions, when executed by the
one or more processors, cause the processing system to perform the
various functions described herein.
[0064] The wireless device 202 may also include a housing 208 that
may include a transmitter 210 and/or a receiver 212 to allow
transmission and reception of data between the wireless device 202
and a remote device. The transmitter 210 and the receiver 212 may
be combined into a transceiver 214. An antenna 216 may be attached
to the housing 208 and electrically coupled to the transceiver 214.
The wireless device 202 may also include (not shown) multiple
transmitters, multiple receivers, multiple transceivers, and/or
multiple antennas.
[0065] The wireless device 202 may also include a signal detector
218 that may be used to detect and quantify the level of signals
received by the transceiver 214 or the receiver 212. The signal
detector 218 may detect such signals as total energy, energy per
subcarrier per symbol, power spectral density, and other signals.
The wireless device 202 may also include a digital signal processor
(DSP) 220 for use in processing signals. The DSP 220 may be
configured to generate a packet for transmission. In some aspects,
the packet may comprise a physical layer data unit (PPDU).
[0066] The wireless device 202 may further comprise a user
interface 222 in some aspects. The user interface 222 may comprise
a keypad, a microphone, a speaker, and/or a display. The user
interface 222 may include any element or component that conveys
information to a user of the wireless device 202 and/or receives
input from the user.
[0067] The wireless device 202 may also an MRP component 224. When
the wireless device 202 is implemented as an AP, the MRP component
224 may control a process of requesting a plurality of STAs to
jointly enable and disable a medium reserving procedure for
communication based on at least one of that each STA of the
plurality of STAs has uplink traffic with the AP or that each STA
of a subset of STAs of the plurality of STAs has a hidden node that
transmits data to the AP and disrupts a communication between the
AP and the each STA. The MRP component 224 may control a process of
receiving, from the plurality of STAs, information indicating a
communication metric while jointly enabling or disabling the medium
reserving procedure for communication. The MRP component 224 may
control a process of determining, based on the received information
indicating the communication metric, whether the joint enablement
of the medium reserving procedure improves communication for the
plurality of STAs. The MRP component 224 may control a process of
requesting the plurality of STAs to jointly enable the medium
reserving procedure for subsequent communication when the joint
enablement of the medium reserving procedure improves communication
for the plurality of STAs.
[0068] When the wireless device 202 is implemented as a STA, the
MRP component 224 may control a process of sending, in accordance
with an RTS/CTS procedure, one or more RTS messages to a second
STA. The MRP component 224 may control a process of receiving zero
or more CTS messages in response to the RTS messages from the
second STA. The MRP component 224 may control a process of
determining a response rate based on the RTS messages and the CTS
messages. The MRP component 224 may control a process of sending a
first switching request to the second STA when the response rate
meets a threshold, the first switching request requesting the
second STA to implement a polling procedure, the polling procedure
announcing receiver availability for receiving data
transmission.
[0069] The various components of the wireless device 202 may be
coupled together by a bus system 226. The bus system 226 may
include a data bus, for example, as well as a power bus, a control
signal bus, and a status signal bus in addition to the data bus.
Components of the wireless device 202 may be coupled together or
accept or provide inputs to each other using some other
mechanism.
[0070] Although a number of separate components are illustrated in
FIG. 2, one or more of the components may be combined or commonly
implemented. For example, the processor 204 may be used to
implement not only the functionality described above with respect
to the processor 204, but also to implement the functionality
described above with respect to the signal detector 218, the DSP
220, the user interface 222, and/or the MRP component 224. Further,
each of the components illustrated in FIG. 2 may be implemented
using a plurality of separate elements.
A. Full Buffer Hidden Node
[0071] FIG. 3 is a diagram 300 illustrating wireless devices in a
wireless network. As shown, a station A 302 has a transmission
range 304. A station B 306, a station C 310, and an access point
320 are within the transmission range 304 and can receive signal
communication from the station A 302. A station D 314 has a
transmission range 316. The station C 310 and the access point 320
are within the transmission range 316 and can receive signal
communication from the station D 314. The station A 302 and the
station D 314 are outside the transmission ranges of each other and
may not receive signal communication from each other. Thus, the
station A 302 and the station D 314 may be considered as hidden
nodes or hidden stations to each other.
[0072] FIG. 4 is a diagram 400 illustrating signal communication
among wireless devices having full buffer neighboring devices in a
wireless network. For simplicity and clarity, some technical
features may be omitted from the figures. As shown, in this
example, from time t10 to t20, the station D 314 is transmitting a
data frame 410 to the station C 310. From time t30 to t40, the
station D 314 is transmitting a data frame 414 to the station C
310. From time t50 to t60, the station D 314 is transmitting a data
frame 418 to the station C 310. The station D 314 may have
substantial amount of data to be transmitted to the station C 310.
Accordingly, the transmission buffer at the station D 314 may be
substantially occupied all the time and may have little idle time.
The inter-frame spacing between the data frame 410 and the data
frame 414 as well as between the data frame 414 and the data frame
418 (e.g., the time period from t20 to t30 and the time period from
t40 to t50) may be configured to be a short inter frame space
(SIFS). The transmission buffer of the station D 314 may be
considered as a full buffer, and the data transmission from the
station D 314 to station C 310 may be considered as a full buffer
transmission. As will be described infra in more detail, the full
buffer transmission from the station D 314 to the station C 310 may
cause issues to other stations (e.g., the station A 302) that
attempt to transmit data to the station C 310.
[0073] In this example, the station A 302 may attempt to
communicate with the station C 310 using the same carrier as is
used by the station D 314 to transmit data. Particularly, from time
t05 to t15, the station A 302 may transmit a data frame 422 to the
station C 310. The time t05 is prior to time t10 and time t15 is
subsequent to time t10 (at which the station D 314 starts
transmitting the data frame 410 to the station C 310). Note that
the station D 314 is out of the transmission range 304 of the
station A 302 and, thus, does not sense that the station A 302 is
using the carrier. Consequently, the station D 314 at time t10 does
not withhold data transmission in order to prevent data collisions.
Because the data frame 410 and the data frame 422 interferes with
each other at the station C 310, each of the data packets used to
transmit the data frame 410 and the data frame 422 may or may not
be successfully received at the station C 310. In other words, the
data frame 410 transmitted from the station D 314 interferes with
the data frame 422 transmitted from the station A 302 at the
station C 310. Thus, an issue exists in that the data frame 422 may
not be correctly received at the station C 310.
A.1 RTS/CTS Does Not Solve Full Buffer Hidden Node Issue
[0074] After several attempts to transmit data frames to the
station C 310, in one technique, the station A 302 may decide to
initiate a medium reserving procedure such as a Request-to-Send
(RTS)/Clear-to-Send (CTS) procedure to protect data transmission
based on PER, retry rate, or packet length. The PER is the number
of incorrectly received data packets divided by the total number of
received packets. A packet is declared incorrect if at least one
bit is erroneous. Using the RTS/CTS procedure, when the station A
302 has a frame to send, the station A 302 can initiate the
procedure by sending an RTS frame. The RTS frame serves several
purposes: in addition to reserving the radio link for transmission,
it silences any stations that hear it. If the station C 310
receives the RTS frame, it responds with a CTS frame. Like the RTS
frame, the CTS frame silences stations in the immediate vicinity.
Once the RTS/CTS exchange is complete, the station A 302 can
transmit its frames without worry of interference from any hidden
nodes. Hidden nodes beyond the range of the sending station are
silenced by the CTS from the receiver. When the RTS/CTS medium
reserving procedure is used, frames may be positively
acknowledged.
[0075] In the example discussed with reference to FIG. 4, an issue
still exists.
[0076] Particularly, enabling an RTS/CTS procedure based on PER,
retry rate, or packet length may not improve the throughput between
the station A 302 and the station C 310 due to the full buffer data
transmission from the station D 314 to the station C 310. For
example, after transmitting the data frame 422, based on the PER,
the station A 302 may attempt to initiate an RTS/CTS procedure.
More specifically, at time t18, the station A 302 transmits an RTS
frame to the station C 310. The station C 310 is receiving the data
frame 422 at time t18 and, thus, may not detect the RTS frame and
may treat the RTS frame as interference. Consequently, the station
C 310 does not transmit a CTS frame in response back to the station
A 302. The station A 302 waits a CTS frame sent from the station C
310 for a predetermined time period. If the station A 302 does not
receive a CTS frame from the station C 310 in the predetermined
time period, the station A 302 may send another RTS frame at time
t35. At time t35, the station C 310 is receiving the data frame 414
from the station D 314 and may not respond with a CTS frame back to
the station A 302. In other words, in this example, enabling a
medium reserving procedure (e.g., an RTS/CTS procedure) at the
station A 302 may not increase data throughput at the station A
302, because CTSs from the station C are not frequently returned to
the station A 302. In addition, such issues still exist if the
station D 314 transmits data packets to nodes other than the
station C 310, because the station C 310 may miss an RTS from
station A 302 due to interference of packets from station D
314.
[0077] Further, an issue exists in that the air time and throughput
of the station A 302 may drop significantly after enabling RTS/CTS
due to low CTS return rate, although PER or interference can be
reduced. In other words, medium usage can be significantly reduced
due to low CTS return rate. The station C 310 (e.g., the receiver)
needs to check if the channel is busy at its side before responding
with a CTS. The station C 310 will not respond with a CTS if an RTS
is not received due to interference or due to channel being busy
(e.g., a network allocation vector (NAV) is set by previous frames
from other nodes).
[0078] To address these issues, as will be described infra with
reference to FIG. 5, the station A 302 and the station C 310 can be
configured to consider enabling the RTS/CTS procedure based on
criteria other than PER, retry rate, or packet length.
B. Criteria for Enabling RTS/CTS with Respect to a STA
[0079] FIG. 5 is a diagram 500 illustrating signal communication
among wireless devices having full buffer neighboring devices and
implementing an RTS/CTS enablement technique in a wireless network
in accordance with an aspect of the present disclosure. In this
example, from time t10 to time t20, the station A 302 transmits a
data frame 510 to the station C 310. As illustrated in FIG. 3, the
station D 314 is not within the transmission range 304 of the
station A 302. Therefore, the station D 314 does not sense the data
frame 510 transmitted on the carrier. The station D 314 may
consider that the station C 310 is available and may transmit a
data frame 514 to the station C 310 from time t14 to t25, which is
between time t10 and t20. The station C 310 at time t14 is
receiving the data frame 510 from the station A 302, and may sense
the data frame 514 as interference.
[0080] In one configuration, to address the issue of reduced medium
usage due to low return rate of CTSs described supra, the station A
302 is configured to consider enabling an RTS/CTS procedure based
on whether physical layer convergence procedure (PLCP) protocol
data units (PPDUs) transmitted to the station C 310 are frequently
hit by interference in the middle (e.g., after the preamble) of a
transmission. Further, the station A 302 may be configured to use
an evaluation procedure to determine whether enabling an RTS/CTS
procedure to transmit data to the station C 310 can improve
throughput of the station A 302. When the received PPDUs frequently
suffer hidden node interference at the station C 310, the station A
302 may decide to enable an RTS/CTS procedure if the throughput of
the station A 302 can be improved. The throughput metrics used in
the evaluation procedure can include an actual throughput and an
equivalent full buffer throughput. The detection of received PPDUs
frequently suffering hidden node interference at the station C 310
can be based on techniques described infra.
B.1 Technique Based on Signal Metric
[0081] In one configuration, the station A 302 may be configured to
implement a technique based on signal metrics at the station C 310
and/or at the station A 302. The station C 310 may be configured to
measure multiple times or continuously one or more of signal
metrics such as a received signal strength indication (RSSI), an
estimated channel coefficient, an estimated phase/frequency offset,
and a pilot error vector magnitude of the PPDUs of the data frame
510. If station C 310 determines that there is a sudden change of a
measured signal metric, the station C 310 may conclude that the
data transmission of the data frame 510 is interfered by another
data transmission. For example, the station C 310 may measure a
signal metric (e.g., RSSI) at a first location of a PPDU of the
data frame 510 at time t13 and measure the signal metric at a
second location of the PPDU at time t15. If the difference between
the two measurements is greater than a predetermined threshold, the
station A 302 may determine to enable the RTS/CTS procedure or to
initiate the evaluation procedure. For example, when measuring
RSSI, if the difference is greater than 10 decibels, the station A
302 may decide to initiate the RTS/CTS procedure.
[0082] The station C 310 may report back to the station A 302 the
values of one or more measured signal metrics (e.g., RSSI) at two
or more locations of a data packet. The station C 310 may report
back to the station A 302 the difference of the values of a
measured signal metric (e.g., RSSI) at two locations of a data
packet. The signal metric information can be transmitted in a
dedicated data frame or can be embedded in one or more existing
data frames and/or management frames. The station A 302 can then
determine whether to enable the RTS/CTS procedure or whether to
initiate an evaluation procedure. The evaluation procedure
evaluates whether enabling a medium reserving procedure can improve
the data throughput at the station A 302. Alternatively, the
station C 310 may report back to the station A 302 an indicator
that the difference of the values of a measured signal metric
(e.g., RSSI) at two locations of a data packet exceeds a threshold,
which can be set by station A 302, the station C 310, or both
through negotiation. The station A 302 may then decide to initiate
the RTS/CTS procedure or an evaluation procedure.
B.2 Technique Based on Block Acknowledgement
[0083] In one configuration, the station A 302 may be configured to
implement a technique based on information obtained from a block
acknowledgement transmitted from the station A 302. For example,
after transmitting the data frame 510 from time t10 to t20 at the
station A 302, the station A 302 may transmit a data frame 518 from
time t30 to time t40. The station A 302 may consider the data frame
410 and the data frame 418 as a data block, and may subsequently
transmit a block acknowledgment request frame 522 at time t50 to
the station C 310. Upon receiving the block acknowledgment request
frame 522, the station C 310 may choose to send an immediate block
acknowledgment frame 524 or a delayed block acknowledgment frame
528. The immediate block acknowledgment frame 524 and the delayed
block acknowledgment frame 528 each may include a starting sequence
number (SSN), which is the sequence number of the oldest MAC
service data unit medium access control (MAC) service data unit
(MSDU) in the block for which an acknowledgement is needed. On
receiving the block acknowledgment request frame 522, the station C
310 may prepare the immediate block acknowledgment frame 524 or the
delayed block acknowledgment frame 528, which includes a bitmap
where the first bit represents the MAC protocol data unit (MPDU)
with the same sequence number as the SSN from the block
acknowledgment request frame 522 and subsequent bits indicate
successive sequence numbers. The bitmap thus forms an array indexed
by sequence number with the SSN as starting reference.
[0084] In one configuration, the station C 310 may transmit the
immediate block acknowledgment frame 524 after a short amount of
time (e.g., a SIFS) upon receiving the block acknowledgment request
frame 522. In another configuration, the station may transmit the
delayed block acknowledgment frame 528 in a subsequent, separate
channel access. The immediate block acknowledgment frame 524 and
the delayed block acknowledgment frame 528 each acknowledge data
units correctly received at the station C 310 from the previous
block. The station A 302 may re-queue data units which were not
correctly received and may send them in the subsequent block.
[0085] In one configuration, the station A 302 may determine the
interference at the station C 310 and accordingly determine whether
to initiate the evaluation procedure based on the information of
the data units that are correctly received at the station C 310
indicated in the immediate block acknowledgment frame 524 or
delayed block acknowledgment frame 528. For example, the station A
302 may determine the number of the data units (e.g., MPDUs) in a
data block (e.g., one or more PPDUs or data frames) that are not
correctly received at the station C 310. If the number is greater
than a predetermined threshold, the station A 302 may determine
that interference exists and that the evaluation procedure should
be initiated. In addition or alternatively, the station A 302 may
determine a ratio of the data units not correctly received at the
station C 310 with respect to the total units of a data block. If
the determined ratio is greater than a predetermined threshold
(e.g., 10%, 15%, or 20%), the station A 302 may determine that
interference exists and that the RTS/CTS procedure should be
enabled or the evaluation procedure should be initiated.
[0086] In addition or alternatively, the station A 302 may
determine a distribution of the data units not correctly received
at the station C 310 within the data block. For example, the
distribution may indicate that the first half of the data units are
received correctly but the second half of the data units are not.
In the example with respect to FIG. 5, the station A 302 may
receive an immediate block acknowledgment frame 524 or delayed
block acknowledgment frame 528 indicating that the data units
transmitted after time t14 are not correctly received. If the
distribution matches a predetermined pattern, the station A 302 may
determine that interference exists and that the RTS/CTS procedure
should be enabled or the evaluation procedure should be initiated.
Alternatively, the station C 310 may report back to the station A
302 an indicator that interference is detected based on
distribution. The station A 302 may then decide to initiate the
RTS/CTS procedure or an evaluation procedure.
B.3 Technique Based a Measured PER and an Estimated PER
[0087] In one configuration, the station A 302 may be configured to
implement a technique based on a measured PER and an estimated PER.
Specifically, the station A 302 can determine interference at the
station C 310 based on PER. For example, while transmitting data
frame 510 and data frame 518 and other data frames, the station A
302 or the station C 310 can measure the actual PER. Further, the
station A 302 can obtain a signal-to-noise ratio (SNR) of signal
reception at the station C 310, which excludes interference. Based
on the SNR, the station A 302 can further determine an estimated
PER for a given MCS. For example, the station C 310 may send an
acknowledgment that includes an RSSI to the station A 302. Based on
the RSSI, the station A 302 can determine the SNR at the station C
310. The station A 302 then compares the actual PER with the
estimated PER. If the difference between the PER and the estimated
PER is greater than a predetermined threshold, the station A 302
may determine that interference exists and that the RTS/CTS
procedure should be enabled or the evaluation procedure should be
initiated.
B.4 Evaluation Procedure
[0088] Once the station A 302 has determined that it should
consider enabling the RTS/CTS procedure, the station A 302 can use
an evaluation procedure to determine whether the RTS/CTS procedure
can improve the throughput of the station A 302. During the
evaluation procedure, the station A 302 can transmit data to the
station C 310 using the RTS/CTS procedure in a first time period
and then transmit data without using the RTS/CTS procedure in a
second time period. The station A 302 can determine the values of
one or more throughput metrics in both periods and then determine
whether using the RTS/CTS procedure to transmit data improves the
throughput of the station A 302 based on the values of the
throughput metrics.
[0089] For example, the throughput metric can be an actual
throughput measured at the station A 302 or the station C 310. In
one technique, the actual throughput can be the data units
successfully received at a receiver divided by the total time
period used to transmit the data (e.g., transmission time). For
example, referring to FIG. 5, the actual throughput can be the data
units of the data frame 510 and the data frame 518 that are
acknowledged in the immediate block acknowledgment frame 524
divided by the time period from time t0 to time t65. The time
period from time t0 to time t10 is a contention period.
[0090] As another example, the throughput metric can be an
equivalent full buffer throughput measured at the station A 302. In
one technique, the equivalent full buffer throughput can be the
data units successfully received at a receiver divided by the total
time period used to transmit the data excluding the buffer idle
time. For example, referring to FIG. 5, the equivalent full buffer
throughput can be the data units of the data frame 510 and the data
frame 518 that are acknowledged in the immediate block
acknowledgment frame 524 divided by the time period from time t0 to
time t20 plus the time period from time t30 to t65, in which the
station A 302 has buffered data.
[0091] The station A 302 then may determine the difference between
the values of throughput metric in the first time period and the
second time period. If the difference is greater than a
predetermined threshold (e.g., 5/10/15 Mbps or 5%/10%/15%), the
station A 302 can then determine that using the RTS/CTS procedure
improves the throughput of the station A 302.
C. Full Buffer Hidden Node with Respect to an AP
[0092] FIG. 6 is a diagram 600 illustrating signal communication
among wireless devices in a wireless network. At operation 602, the
station A 302 transmits a data packet (e.g., a PPDU) to the access
point 320. At operation 606, the station D 314 transmits a data
packet to the access point 320. At operation 610, the station A 302
transmits another data packet to the access point 320.
Subsequently, at operation 614, the station D 314 transmits another
data packet to the access point 320. As described supra was
reference to FIG. 3, the station D 314 is out of the transmission
range 304 of the station A 302 and may not sense the data
transmission of operation 602 or of operation 610. Therefore, data
transmission of operation 606 or operations 614 may start while the
data transmission of operation 602 or operation 610 is still
ongoing, respectively. At operation 618, the station A 302
transmits a block acknowledgment request to the access point 320.
At operation 622, the access point 320 transmits a block
acknowledgment. Because the station D 314 is within the range of
the access point 320, the station D 314 can also receive the block
acknowledgment. In some situations, the station D 314, as described
supra with reference to FIG. 5, may be a full buffer hidden node.
An issue exists in that the station D 310, which is a full buffer
hidden node to the station A 302, may interfere with the data
transmission from the station A 302 to the access point 320.
Further, as described supra with reference to FIG. 3, simply
enabling the RTS/CTS procedure at the station A 302 may not improve
the throughput of the station A 302.
C.1 Technique for Identifying a Hidden Node Based on Signal
Metrics
[0093] In one configuration, the access point 320 can use the
techniques described supra with reference to FIG. 5 regarding
signal metrics to identify a hidden node of the station A 302.
Particularly, the access point 320 can detect that data reception
for receiving data from the station A 302 is interfered. The
techniques include obtaining an indication of at least one of (a) a
change of a signal metric of a first data packet received from the
station, (b) one or more data units in a second data packet that
have not been correctly received from the station, or (c) a
difference between an estimated PER and a measured PER of data
packets received from the station. For example, the access point
320 can determine that the data packets received from the station A
302 are frequently hit by interference in middle, e.g., after
preamble. The access point 320 can learn this by examining sudden
changes of RS SI and estimated phase/frequency within each data
packet. Accordingly, the access point 302 can determine that the
station A 302 has a hidden node.
C.2 Techniques for Identifying a Hidden Node Based on a Block
Acknowledgement
[0094] In one configuration, the access point can use the
techniques described supra with reference to FIG. 5 regarding block
acknowledgements to identify a hidden node of the station D 304.
Particularly, in some situations, the station A may be a full
buffer hidden node to the station D. Data transmission from the
station D 314 to the access point 320 may also be interfered by the
data transmission from the station A 302 to the access point 320.
At operation 626, the station D 314 can determine that a hidden
node (e.g., the station A 302) exists when the station D 314
receives the block acknowledgment transmitted in operation 622, but
did not receive the data packets transmitted in operations 602 and
610 at a time point that is a predetermined time period (e.g., an
inter frame spacing) prior to receiving the block acknowledgment.
For example, referring to FIG. 5, in one configuration, at time
t60, the station D 314 may receive the immediate block
acknowledgment frame 524, but may not receive a block
acknowledgment request frame 522 sent at time t50 to time t56 or
may not receive the data frame 518 sent at time t30 to t40. The
inter frame spacing between the data frame 518 and the block
acknowledgment request frame 522 as well as the inter frame spacing
between the block acknowledgment request frame 522 and the
immediate block acknowledgment frame 524 can be a short inter frame
space (SIFS).
[0095] In another configuration, at operation 622, the access point
320 may transmit the delayed block acknowledgment frame 528 in
response to the block acknowledgment request frame 522. The spacing
between the delayed block acknowledgment frame 528 and the block
acknowledgment request frame 522 (e.g., from time t56 to time t80
in FIG. 5) may not be a SIFS. The access point 320 can be
configured to set a data unit (such as a bit) in a block
acknowledgment frame to indicate that a PPDU is received at the
access point 320 from the destination of the block acknowledgment
frame at or within a specified time period (such as a SIFS or 50
microseconds) prior to the transmission time of the block
acknowledgment frame (e.g., at time t40 or time t56). In this
example, the access point 320 sends a delayed block acknowledgment
frame 528 with the data unit to the station D 314. (In another
example, the access point 320 sends an immediate block
acknowledgment frame 524 with the data unit to the station D 314).
The station D 314, upon receiving the delayed block acknowledgment
frame 528 at operation 622, can first detect whether this data unit
is present in the delayed block acknowledgment frame 528. Upon
determining that the data unit is present, the station D 314 can
learn that a PPDU is transmitted to the access point 320 at or
within the specified time period prior to the transmission time of
the block acknowledgment frame. Then the station D 314 can
determine whether the station D 314 has received the PPDU at or
within the relevant time from the node whose MAC address is the
same as the destination address of the block acknowledgment frame.
If the station D 314 has not received the PPDU, the station D 314
can determine that a hidden nod exists. In one configuration, the
station D 314 may only consider delayed block acknowledgment frame
528 when this data unit is set. The data unit can be one of the
nine reserved bits B3-B11 in the control field of each delayed
block acknowledgment frame 528.
[0096] The immediate block acknowledgment frame 524 and the delayed
block acknowledgment frame 528 each contain the source and
destination MAC addresses and may also contain partial association
ID (PAID) of the destination device. The station D 314 can
determine that the destination MAC address and the PAID are
associated with a hidden note (e.g., the station A 302).
[0097] At operation 630, the station D 314 can transmit a report to
the access point 320. The report can include the identification of
the hidden node (e.g., the station A 302). Optionally, prior to
operation 630 at operation 626, the station D 314 may decide to
request the access point 320 to instruct both the station A 302 and
the station D 314 to use the RTS/CTS procedure to transmit data to
the access point 320. In this technique, the station D 314 can
transmit the request, for example in the report of operation 630,
to the access point 320.
[0098] At operation 634, in certain configurations, the access
point 320 can decide to request the station A 302 and another
station communicating with the access point 320 (e.g., the station
D 314) to jointly use the RTS/CTS procedure to transmit data to the
access point 320 based on the indications detected with respect to
data reception from the station A 302 as described supra. In
certain configurations, if the access point 320 has determined
(e.g., using the operations described supra with respect to FIG. 5)
that a ratio of stations with uplink traffic and having hidden
nodes with respect to all of the stations with uplink traffic is
greater than a predetermined threshold (e.g., 50%), the access
point 320 can request all the stations with uplink traffic to
enable the RTS/CTS procedure. In certain configurations, the access
point 320 can decide to request the station D 314 and a hidden node
of the station D 314 identified in the report of operation 630
(e.g., the station A 302) to jointly use the RTS/CTS procedure to
transmit data to the access point 320. In certain configurations,
the access point 320 can decide to request the station A 302 and
the station D 314 to jointly use the RTS/CTS procedure to transmit
data to the access point 320 upon receiving a request requesting
the same as described supra.
C.3 Joint Enablement Information Element Format
[0099] To address the hidden node issue described supra with
reference to FIG. 6, the access point 320 can be configured to,
upon identifying that the station A 302 and/or the station D 314
have a hidden node, request the station A 302 and the station D 314
to jointly enable the RTS/CTS procedure.
[0100] FIG. 7 is a diagram 700 illustrating formats of information
elements (IEs) used to signal joint enablement of the RTS/CTS
procedure. In one configuration, a joint RTS/CTS IE 710 has an
element ID field 711, a length field 712, a group indicator field
715, an RTS on start time field 716, an RTS on duration field 717,
an RTS off start time field 718, and an RTS off duration field
719.
[0101] The element ID field 711 identifies the element such that a
receiving station can distinguish the joint RTS/CTS IE 710 from
other IEs. The group indicator field 715 indicates the stations
that belong to the same group for enabling and disabling the
RTS/CTS procedure. The length field 712 indicates the length of
remaining fields in the joint RTS/CTS IE 710. The RTS on start time
field 716 indicates a time at which the receiving station is
requested to enable the RTS/CTS procedure, that is, to start using
the RTS/CTS procedure to transmit data to the access point 320. The
RTS on duration field 717 indicates a time duration during which
the receiving station is requested to enable the RTS/CTS procedure,
that is, to continuously use the RTS/CTS procedure to transmit data
to the access point 320. The RTS off start time field 718 indicates
a time at which the receiving station is requested to disable the
RTS/CTS procedure, that is, to start transmitting data to the
access point 320 without using the RTS/CTS procedure. The RTS off
duration field 719 indicates a time duration during which the
receiving station is requested to disable the RTS/CTS procedure,
that is, to continuously transmit data to the access point 320
without using the RTS/CTS procedure.
[0102] An access point that is capable of handling joint enablement
can construct a joint RTS/CTS IE 710. The access point can
configure the group indicator field 715 to specify the stations
that are requested to enable the RTS/CTS procedure. The group
indicator field 715 can specify the MAC addresses or association
IDs (AID) of the selected stations. Alternatively, the group
indicator field 715 can be a sequence of bits. Each bit position
equal to a distinct station AID. In one configuration, a station is
included in a requested group if the bit corresponding to the AID
of the station is set to 1. The access point can further configure
the RTS on start time field 716 and the RTS on duration field 717
to set a time period in which the group of selected stations is
requested to enable the RTS/CTS procedure. The access point can
also configure the RTS off start time field 718 and the RTS off
duration field 719 to set a time period in which the group of
selected stations is requested to disable the RTS/CTS procedure.
The access point can transmit the joint RTS/CTS IE 710 to the
selected stations for example through a management frame.
[0103] In another configuration, a joint RTS/CTS IE 750 has an
element ID field 751, an existence indicator field 753, a report
indicator field 754, a length field 752, a group indicator field
755, an RTS on start time field 756, an RTS on duration field 757,
an RTS off start time field 758, and an RTS off duration field 759.
The element ID field 751, the length field 752, the group indicator
field 755, the RTS on start time field 756, the RTS on duration
field 757, the RTS off start time field 758, and the RTS off
duration field 759 are similar to the element ID field 711, the
length field 712, the group indicator field 715, the RTS on start
time field 716, the RTS on duration field 717, the RTS off start
time field 718, and the RTS off duration field 719 of the joint
RTS/CTS IE 710. Comparing to the joint RTS/CTS IE 710, the joint
RTS/CTS IE 750 has two additional optional fields, that is, the
existence indicator field 753 and the report indicator field
754.
[0104] In one configuration, only the element ID field 751 and the
length field 752 are required in the joint RTS/CTS IE 750 and all
other fields may be optional. For example, the joint RTS/CTS IE 750
may not include the group indicator field 755. Accordingly, the
stations are configured to interpret such a joint RTS/CTS IE 750
without a group indicator field 755 as an indication that all
receiving stations are selected to operate as instructed by the
joint RTS/CTS IE 750. The access point can use this format to
instruct all receiving stations with uplink traffic to the access
point to enable the RTS/CTS procedure. For example, where the
access point has determined (e.g., using the operations described
supra with respect to FIG. 5) that a ratio of the number of
stations having hidden nodes with respect to all of the stations
communicating with the access point is greater than a predetermined
threshold (e.g., 50%), the access point can transmit a joint
RTS/CTS IE 750 with this format to all the receiving stations to
request joint enablement of the RTS/CTS procedure by all the
receiving stations. Further, the joint RTS/CTS IE 750 may not
include the time fields 756, 757, 758, 759. Accordingly, a station
can be configured to enable the RTS/CTS procedure whenever it has
received such a joint RTS/CTS IE 750.
[0105] As described supra, the report indicator field 754, the
group indicator field 755, the RTS on start time field 756, the RTS
on duration field 757, the RTS off start time field 758, and the
RTS off duration field 759 may be optional. In one configuration,
the joint RTS/CTS IE 750 can use the existence indicator field 753
to indicate whether each of the optional fields is included in the
joint RTS/CTS IE 750. For example, the existence indicator field
753 may include a series of bits each of which corresponds to an
optional field. If an optional field exists in the block, the
corresponding bit can be set to a first value such as 1. If an
optional field is does not exist in the joint RTS/CTS IE 750, the
corresponding bit can be set to a second value such as 0.
[0106] The report indicator field 754 can be included in the joint
RTS/CTS IE 750 to solicit report of a throughput metric. In
combination with the RTS on start time field 756, the RTS on
duration field 757, the RTS off start time field 758, and the RTS
off duration field 759, the access point can configure the joint
RTS/CTS IE 750 having a report indicator field 754 to request the
selected stations to report the throughput metric in each indicated
time period back to the access point. Alternatively, the access
point can send a separate frame after the indicated periods to
request a report from the selected stations.
[0107] In one configuration, first and second predetermined values
of the element ID field 751 can be used to signal requests for
enablement and disablement of the RTS/CTS procedure, respectively.
A joint RTS/CTS IE 750 having an element ID field 751 configured as
such, can use one set of the time fields (e.g., RTS on start time
field 756 and RTS on duration field 757, or alternatively, RTS off
start time field 758 and RTS off duration field 759) to signal a
selected time for either enablement or disablement.
[0108] In another configuration, instead of using a dedicated IE,
the joint RTS/CTS indicator can be represented by a bit at a
predetermined location of any specified frame. For example, 1 and 0
may correspond to enabling and disabling RTS/CTS, respectively, for
all associated stations. The bit can be in any part of any frame
from the AP. For example, this bit can be in SIG field of frame
preamble or in MAC header of management, control, and data
frames.
C.4 Joint Enablement Procedure
[0109] FIG. 8 is a diagram 800 illustrating signal communication
among wireless devices in a wireless network. In one configuration,
upon identifying hidden nodes, the access point 320 may initially
use an evaluation procedure to determine whether enabling the
RTS/CTS procedure can improve throughput at the station A 302 and
the station D 314. Particularly, at operation 802, the access point
320 may decide to initiate an evaluation procedure with the station
A 302 and the station D 314. The evaluation procedure can determine
whether the station A 302 and the station D 314 jointly by using
the RTS/CTS procedure to transmit data to the access point 320 can
improve throughput of the station A 302 and the station D 314. More
specifically, at operation 806, the access point 320 can transmit a
joined enablement request to both the station A 302 and the station
D 314. The request can be implemented using an IE as described in
FIG. 7, which may be transmitted from the access point 320 to the
station A 302 and the station D 314 through a management frame. The
access point 320 can specify the MAC addresses of the station A 302
and the station D 314 in the group indicator field 715. The access
point 320 can use the RTS on start time field 716 and RTS on
duration field 717 to specify a first time period in which the
station A 302 and the station D 314 are requested to enable the
RTS/CTS procedure. The access point 320 can use the RTS off start
time field 718 and the RTS off duration field 719 to specify a
second time period in which the station A 302 and the station D 314
are requested to disable the RTS/CTS procedure.
[0110] Upon receiving the requests, the station A 302 and the
station D 314 operate to enable and disable the RTS/CTS procedure
as specified in the request. Within the first time period specified
by the request, at operation 810, the station A 302 transmits an
RTS to the access point 320. At operation 814, the access point 320
transmits a CTS to the station A 302. Because the station D 314 is
within the transmission range of the access point 320, the station
D 314 may also receive the CTS and accordingly withhold any data
transmission during the time period indicated in the CTS. At
operation 818, the station A 302 transmits one or more data packets
(e.g., PPDUs) to the access point 320. At operation 822, the
station A 302 transmits another RTS to the access point 320. At
operation 826, the access point 320 transmits another CTS, which is
received by both the station A 302 and the station D 314. At
operation 830, the access point 320 transmits one or more data
packets to the access point 320. At operation 834, the station A
302 transmits a block acknowledgment request to the access point
320. At operation 838, the access point 320 transmits a block
acknowledgment, which may be received by both the station A 302 and
the station D 314.
[0111] At operation 842, still within the first time period, the
station D 314 transmits an RTS to the access point 320. At
operation 846, the access point 320 transmits a CTS, which may be
received by both the station A 302 and the station D 314. At
operation 850, the station D 314 transmits one or more data packets
to the access point 320. At operation 854, the station D 314
transmits another RTS to the access point 320. At operation 858,
the access point 320 transmits another CTS, which may be received
by both the station A 302 and the station D 314. At operation 862,
the station D 314 transmits one or more data packets to the access
point 320. At operation 866, the station D 314 transmits a block
acknowledgment request to the access point 320. At operation 870,
the access point 320 transmits a block acknowledgment, which may be
received by both the station A 302 and the station D 314.
[0112] At operation 871, the access point 320 can determine, using
the techniques described supra with reference to FIG. 3, the values
of one or more throughput metrics at the station A 302 and the
station D 314, respectively, in the first time period. For example,
the throughput metric can be an actual throughput measured at the
access point 320, the station A 302, and the station D 314. As
another example, the throughput metric can be an equivalent full
buffer throughput measured at the station A 302 and the station D
314. The stations may report those metrics to the AP if they are
measured by stations. The AP can indicate stations to report or not
in the joint RTS/CTS enablement IE described supra. In certain
configurations, the access point 320 may use communication metric
other than the throughput metric. The communication metric may
include at least one of an actual throughput, an equivalent full
buffer throughput, a retry rate, a packet error rate (PER), a
modulation coding scheme (MCS), or an access delay.
[0113] Subsequently, within the second time period, at operation
872, the station A 302 transmits one or more data packets to the
access point 320. At operation 874, the station D 314 transmits one
or more data packets to the access point 320. At operation 876, the
station A 302 transmits one or more data packets to the access
point 320. At operation 878, the station A 302 transmits a block
acknowledgment request to the access point 320. At operation 880,
the access point 320 transmits a block acknowledgment, which may be
received by both the station A 302 and the station D 314. At
operation 882, the station D 314 transmits one or more data packets
to the access point 320. At operation 884, the station D 314
transmits a block acknowledgment request to the access point 320.
At operation 886, the access point 320 transmits a block
acknowledgment, which may be received by both the station A 302 and
the station D 314.
[0114] At operation 888, the access point 320 can determine again,
using the techniques described supra with reference to FIG. 5, the
values of the one of more throughput metrics at the station A 302
and the station D 314, respectively, in the second time period.
Subsequently, the access point 320 can use the techniques described
supra with reference to FIG. 5 to determine whether the station A
302 and the station D 314 jointly using the RTS/CTS procedure to
transmit data to the access point 320 can improve throughput of the
station A 302 and the station D 314. Subsequently, the access point
320 can transmit another request for enabling the RTS/CTS procedure
to the station A 302 and the station D 314, in response to a
determination that joint enablement of the RTS/CTS procedure by the
station A 302 and the station D 314 can improve the throughput of
the station A 302 and/or the station D 314. The request instructs
the station A 302 and the station D 314 to enable the RTS/CTS
procedure. The request can further specify a time period of the
requested joint enablement.
D. Enhancement Procedure
[0115] D.1 Busy Neighbor Receiving Data from a Hidden Node
[0116] FIG. 9 is a diagram 900 illustrating wireless devices in a
wireless network. A station 914 is transmitting data to a station
910. A station 902 and a station 906 are out of the transmission
range 916 of the station 914. Thus, the station 902 and the station
906 do not sense the data transmission from the station 914 to the
station 910. While the station 914 is transmitting to the station
910, the station 902 may transmit an RTS to the station 906. Still
during the transmission, the station 906 may transmit a CTS to the
station 902. Because the station 910 is busy receiving data from
the station 914, the station 910 does not detect the RTS or the
CTS. After successfully communicating the RTS and the CTS, the
station 902 and the station 906 determines that the medium is clear
and starts transmitting data. While the data transmission between
the station 902 and the station 906 is ongoing, the station 910,
which did not detect the RTS or the CTS, may determine that the
medium is clear and start transmitting data to the station 914.
Because the station 902 and the station 906 are within the
transmission range 912 of the station 910, the data transmission
from the station 910 can also reach the station 902 and the station
906 and become interference to the station 902 and the station
906.
D.1.a Technique to Request Neighbor to Reduce Over the Air Medium
Occupancy
[0117] In one configuration, the station 902 and/or the station 906
can use an enhancement procedure to reduce the interference from
the data transmission between the station 910 and the station 914.
For example, the station 902 or the station 906 can transmit a
request requesting the neighbors of the station 902 and the station
906 to reduce an over the air (OTA) medium occupancy. For example,
the station 902 or the station 906 can request the station 910 to
use less aggressive enhanced distributed channel access (EDCA)
parameters for communication (e.g., communication with the station
914). As another example, the station 902 or the station 906 can
request the station 910 to maintain one or more dedicated silence
periods. Further, the dedicated silence periods can be periodic.
Thus, the station 910 may have more idle time to capture the
RTS/CTS transmitted between the station 902 and that the station
906.
D.2 Available Neighbor Interfered by a Full Buffer Hidden Node
[0118] Further, in some situations, the station 914 may
continuously transmit data to the station 918. Because the station
910 is in the transmission range 916 of the station 914, the
station 910 also receives the data transmission as interference.
The interference strength at the station 910 of the data
transmission from the station 914 may be much stronger than the
signal strength at the station 910 of the RTS transmissions from
the station 902. An issue exists in that the station 910, although
available (idle), may not detect the RTS or CTS transmitted from
the station 902 or the station 906 while the station 910 is
receiving the interference from the station 914 to the station
918.
D.2.a Technique to Transmit RTS/CTS in a Repeating Pattern
[0119] To address the above interference issue, in one
configuration, the station 902 can transmit RTSs to the station 906
or the station 910 in a repeating pattern. FIG. 10 is a diagram
1000 illustrating signal communication among wireless devices in a
wireless network. In configuration 1010, the station 902 can
transmit first RTS 1011-1, second RTS 1011-2, . . . , and N.sup.th
RTS 1011-N to the station 906, N being a predetermined positive
integer. In response, the station 906 transmits first CTS 1012-1,
second CTS 1012-2, . . . , and N.sup.th CTS 1012-N to the station
902. In this particular pattern, each RTS is followed by a CTS. The
inter frame spacing between two RTSs, between two CTSs, as well as
between one RTS and one CTS can be any suitable respective
pre-specified time periods. In this example, the inter frame
spacing between two consecutive RTS and CTS can be the same time
period such as a SIFS. Subsequent to receiving the N.sup.th CTS,
the station 902 transmits one or more data packets 1030 to the
station 906.
[0120] Alternatively, the station 902 can transmit a single first
RTS 1011-1 to the station 906. The station 906, in response,
transmits N CTSs (e.g., first CTS 1012-1, second CTS 1012-2, . . .
, N.sup.th CTS 1012-N) in a repeating pattern. The inter frame
spacing between the RTS and the subsequent CTS as well as between
two consecutive CTSs can be any suitable respective pre-specified
time periods. In this example, the pre-specified time periods can
be the same time period such as a SIFS.
[0121] When the station 902 and the station 906 exchange RTSs/CTSs
in a repeating pattern, it reduces the probability for stations to
miss all the RTSs/CTSs of the station 910 (as well as the station
906). Further, the repeated RTSs/CTSs may be combined for joint
detection and decoding.
[0122] The number of repeats (e.g., the value of N) can be
increased if data packets 1030 still frequently suffer hidden node
interference. The interference can be determined using the
techniques described supra with reference to FIG. 5 such as
determining whether the data packets 1030 are frequently hit by
interference in the middle (e.g., after preamble) or determining
whether the actual PER is much higher than estimated
interference-free PER.
D.2.b Technique to Adaptively Boost RTS/CTS Transmission Power
[0123] To address the above interference issue, in one
configuration, the station 902 and the station 906 can adaptively
boost the RTS/CTS transmission power. For example, initially the
station 902 and the station 906 exchange RTSs/CTSs. As described
supra, data reception at the station 910 is interfered by the data
transmission from the station 914 to the station 918. Thus, the
station 910 may not detect the RTS transmitted from the station
902. If the station 902 and the station 906 detect that data
packets still frequently suffer hidden node interference, the
station 902 and station 906 can increase the transmission power for
RTSs/CTSs to improve detection at low
signal-to-interference-plus-noise ratio (SINR) (e.g., at the
station 910). For example, the station 902 can indicate, in an RTS
or in a beacon frame, a transmission power to be used by the
station 906 for transmitting a CTS. The station 906 can indicate,
in a CTS or an acknowledgment frame, a transmission power to be
used by the station 902 to transmit the next RTS. In one
configuration, this power adaptation technique can be used in
combination with the technique regarding transmitting RTSs/CTSs in
a repeating pattern described supra. For example, each time an
RTS/CTS is repeated, the transmission power of that RTS/CTS is also
increased.
D.2.c Technique to Transmit RTS/CTS at a Different Rate
[0124] To address the above interference issue, in one
configuration, the station 902 and the station 906 can transmit
RTS/CTS at a different rate. For example, if the station 902 and
the station 906 detect that data packets still frequently suffer
hidden node interference after enabling the RTS/CTS procedure, the
station 902 and station 906 can send RTSs/CTSs at a lower data rate
than the previous data rate used in the RTS/CTS procedure. The
lower data rate RTSs/CTSs can be decoded at a low SINR at the
station 910, which is capable of detecting the RTSs/CTSs
transmitted at the lower rate. The station 906, however, may not be
capable of detecting the RTSs/CTSs at the lower rate. The station
902 can be configured to transmit RTS/CTS at the previous, higher
rate prior to or subsequent to the transmission of the RTSs/CTSs at
the lower rate. Subsequent to the RTS/CTS transmission, the station
902 transmits data packets to the station 906. The transmissions of
the RTSs/CTSs as well as the data packets may be within the same
transmit opportunity.
[0125] In a configuration 1050 shown in FIG. 10, the station 902
initially transmits a legacy RTS 1062 to the station 906, which, in
response, transmits a legacy CTS 1072 to the station 902.
Subsequently, the station 902 transmits a next-generation RTS 1064
to the station 906, which, in response, transmits a next-generation
CTS 1074 to the station 902. Subsequently, the station 902
transmits data packets 1080 to the station 906. The inter frame
spacing between any two frames can be any suitable, specified time
period. The inter frame spacing can be the same time period such as
a SIFS. The legacy RTS 1062, the legacy CTS 1072, the
next-generation RTS 1064, the next-generation CTS 1074, and the
data packets 1080 may be within the same transmit opportunity. The
legacy RTS/CTS are sent at legacy rate, e.g. 1 or 6 Mbps, while the
next-generation RTS/CTS can be sent at a higher rate.
[0126] The next-generation RTS/CTS may not be recognized by legacy
devices. To maintain protection from legacy devices, as discussed,
the next-generation RTS/CTS can be used together with a legacy
RTS/CTS. In the configuration 1050, a legacy RTS/CTS is followed by
a next-generation RTS/CTS. The next-generation RTS/CTS can be
decoded by compatible devices at low SINR. The legacy RTS/CTS can
be decoded by legacy devices at normal SINR.
D.3 Busy Receiver with Low Response Rate
[0127] Further, referring back to FIG. 9, while the station 914 is
transmitting data to the station 910, the station 910 may not
frequently respond to RTSs transmitted by the station 902, because
the channel is busy most of time at the station 910. One major
impact of a low CTS response rate is that the station 902 drops
data packets after the number of RTS retries exceeds a max limit.
Dropped data packets may create holes in the received data packet
sequence at the station 910 and may delay date packet delivery to
upper layers. Unsuccessful RTS may also waste medium and increase
interference.
[0128] In other words, the station 910 may receive continuous data
transmission from the station 914. Thus, the station 910 frequently
may not detect the RTSs transmitted from the station 902. An issue
exists in that a low RTS response rate from the station 910 causes
that the station 902 has fewer opportunities to transmit data to
the station 910.
D.3.1 Technique to Determine Whether to Initiate a Switching
Procedure Based on a Response Rate
[0129] In one configuration, the station 902 is configured to
determine a response rate of the station 910. For example, the
station 902 may keep a record of the number (e.g., M) of RTSs
transmitted to the station 910 and the number (e.g., N) of CTSs
received from the station 910 in response to the RTSs. The station
902 may determine a response rate. For example, the response rate
may be the ratio of the number of RTSs and the number of CTSs
(e.g., N/M). If the response rate is less than a predetermined
threshold (e.g., 50%), the station 902 may determine that the
response rate from the station 910 is low.
[0130] Upon detecting a low RTS response rate, the station 902 can
send to the station 910 one or more switching requests with an
observed channel load at the station 902. The switching request
requests the station 910 to confirm switching to using a polling
procedure to transmit data between the station 902 and the station
910. The switching request can be embedded in an IE in a management
frame or a data frame.
[0131] Upon receiving a switching request, the station 910 may
compare the channel load at the station 902 and the channel load at
the station 910. If the channel load at the station 910 is greater
than the channel load at the station 902, the station 910 may
decide to switch to using the polling procedure for data
communication with the station 902. Accordingly, the station 910
transmits a switching confirmation to the station 902.
Alternatively, the station 910 may send the confirmation without
comparing the channel loads. The switching confirmation can be
embedded in an IE in a management frame or a data frame.
[0132] Upon receiving the switching confirmation from the station
910, the station 902 stop transmitting RTSs to the station 910 and
waits to receive from the station 910 a polling request that
announces availability of the station 910.
[0133] If the station 910 determines that the channel load at the
station 910 is not greater than the channel load at the station
902, the station 910 may not transmit a switching confirmation to
the station 902. Without receiving the switching confirmation, the
station 902 continues transmitting RTSs to the station 910.
[0134] In addition or alternatively, the station 910 may keep a
record of the RTSs received from the station 902 and the CTSs sent
to the station 902 in response. The station 910 may not respond a
CTS if NAV is set or other packets with high energy are detected.
Thus, the station 910 may similarly determine a response rate.
Accordingly, when the response rate is lower than a threshold, the
station 910 may send a switching request to the station 902 that
requests the station 902 to confirm that the station 910 may use
the polling procedure for communicating with the station 902. The
switching request may include the channel load at the station 910.
The station 902 may similarly compare the channel load at the
station 902 with the channel load at the station 910 to determine
whether to confirm or deny the switching request. Upon receiving
the switching confirmation from the station 902, the station 910
may send to the station 902 a polling request that announces
availability of the station 910.
[0135] Once the station 910 has determined to use a polling
procedure for data transmission between the station 902 and the
station 910, at a time point when the station 914 is not
transmitting data to the station 910 and the station 910 sense that
the medium is available, the station 910 can send a polling request
to the station 902 to announce the availability of the station 910.
If the station 902 is also available, upon receiving the polling
request from the station 910, the station 902 can start
transmitting data to the station 910. If the station 902 is not
available, the station 910 does not receive data from the station
902 within a predetermined time period (e.g., a SIFS).
Subsequently, if the station 910 is still available, the station
910 can transmit another polling request to the station 902.
[0136] Further, the station 906 may move out of the transmission
range 912 of the station 910 and continuously transmits data to the
station 902. The station 906 does not sense signals transmitted
from the station 910. While the station 906 is transmitting data to
the station 902, the station 902 may not frequently respond to
polling requests transmitted by the station 910, because the
channel is busy most of time at the station 902.
[0137] In other words, the station 902 may receive continuous data
transmission from the station 906. Thus, the station 910 frequently
may not detect the polling requests transmitted from the station
910. A low response rate from the station 902 causes that the
station 902 has fewer opportunities to transmit data to the station
910.
[0138] In one configuration, the station 910 is configured to
determine a response rate of the station 902. For example, the
station 910 may keep a record of the number (e.g., M) of polling
requests transmitted to the station 902 and the number (e.g., N) of
responses (e.g., data) received from the station 902 in response to
the polling requests. If the ratio of the number of podium requests
and the number of responses (e.g., N/M) is less than a
predetermined ratio (e.g., 50%), the station 910 can determine that
the response rate from the station 902 is low.
[0139] Upon detecting a low polling response rate, the station 910
can send to the station 902 one or more switching requests with an
observed channel load at the station 910. The switching request
requests the station 902 to confirm switching to using an RTS/CTS
procedure to transmit data between the station 902 and the station
910. The switching request can be embedded in an IE in a management
frame or a data frame.
[0140] Upon receiving a switching request, the station 902 may
compare the channel load at the station 902 and the channel load at
the station 910. If the channel load at the station 902 is greater
than the channel load at the station 910, the station 902 can
decide to switch to using the RTS procedure for data communication
with the station 910. Accordingly, the station 902 transmits a
switching confirmation to the station 910. The switching
confirmation can be embedded in an IE in a management frame or a
data frame. Alternatively, the station 910 may send the
confirmation without comparing the channel load. Upon receiving the
switching confirmation from the station 902, the station 910 stop
transmitting polling requests to the station 902 and waits to
receive from the station 902 an RTS.
[0141] If the station 902 determines that the channel load at the
station 902 is not greater than the channel load at the station
910, the station 902 may not transmit a switching confirmation to
the station 910. Without receiving the switching confirmation, the
station 910 continues transmitting polling requests to the station
902.
[0142] In addition or alternatively, the station 902 may keep a
record of the polling requests received from the station 910 and
the data sent to the station 910 in response. The station 902 may
not respond to a polling request with data if NAV is set or other
packets with high energy are detected. Thus, the station 902 may
similarly determine a response rate. Accordingly, when the response
rate is lower than a threshold, the station 902 may send a
switching request to the station 910 that requests the station 910
to confirm that the station 902 may use the RTS/CTS procedure for
communicating with the station 910. The switching request may
include the channel load at the station 902. The station 910 may
similarly compare the channel load at the station 910 with the
channel load at the station 902 to determine whether to confirm or
deny the switching request. Upon receiving the switching
confirmation from the station 910, the station 902 may send to the
station 910 an RTS.
[0143] Once the station 902 has determined to use the RTS/CTS
procedure for data transmission between the station 902 and the
station 910, at a time point when the station 906 is not
transmitting data to the station 902 and the station 902 sense that
the medium is available, the station 902 can send an RTS request to
the station 910. If the station 910 is also available, upon
receiving the RTS from the station 902, the station 910 can
transmit a CTS to the station 902. If the station 910 is not
available, the station 902 does not receive a CTS from the station
910 within a predetermined time period (e.g., a SIFS).
Subsequently, if the station 902 is still available, the station
902 can transmit another RTS to the station 910.
[0144] FIG. 11 is a flow chart of an exemplary method 1100 of joint
enablement of a medium reserving procedure. The method may be
performed by an AP (e.g., the access point 104, the access point
320, the apparatus 2902/202). In certain configurations, at
operation 1114, the AP determines that each STA of a subset of STAs
of a plurality of STAs has a hidden node that causes interference
to the AP. The hidden node transmits data to the AP and disrupts a
communication between the AP and the each STA. Further, each STA of
the plurality of STAs has uplink traffic with the AP. The subset of
STAs may include all of the plurality of STAs. For example,
referring to FIG. 8, the access point 320 receives uplink traffic
from the station A 302 and the station D 314. Referring to FIG. 5,
the access point 320 determines that the station D 314 has a hidden
node
[0145] At operation 1116, the AP requests the plurality of STAs to
jointly enable and disable a medium reserving procedure for
communication based on at least one of that each STA of the
plurality of STAs has uplink traffic with the AP or that each STA
of the subset of STAs has a hidden node. The plurality of STAs may
be requested to jointly enable and disable the medium reserving
procedure based on that the plurality of STAs each have uplink
traffic and that a ratio of the subset of STAs with respect to the
plurality of STAs meets a threshold. For example,. referring to
FIG. 8, the access point 320 requests the station A 302 and the
station D 314 to jointly enable and disable the RTS/CTS
procedure.
[0146] At operation 1118, the AP receives, from the plurality of
STAs, information indicating a communication metric while jointly
enabling or disabling the medium reserving procedure for
communication. For example, referring to FIG. 8, the access point
320 determines one or more throughput metrics at the station A 302
and the station D 314.
[0147] At operation 1120, the AP determines, based on the received
information indicating the communication metric, whether the joint
enablement of the medium reserving procedure improves communication
for the plurality of STAs. When the joint enablement of the medium
reserving procedure improves communication for the plurality of
STAs, the AP, at operation 1122, requests the plurality of STAs to
jointly enable the medium reserving procedure for subsequent
communication. When the joint enablement of the medium reserving
procedure does not improve communication for the plurality of STAs,
the AP, at operation 1124, refrains from requesting the plurality
of STAs to jointly enable the medium reserving procedure for
subsequent communication.
[0148] In certain configurations, the medium reserving procedure
employs an RTS/CTS procedure. In certain configurations, the
communication metric includes at least one of an actual throughput,
an equivalent full buffer throughput, a retry rate, a PER, a MCS,
or an access delay.
[0149] FIG. 12 is a flow chart of an exemplary method 1200 for
determining an improvement of the communication metric within
operation 1120 illustrated in FIG. 11. The method may be performed
by an AP (e.g., the access point 104, the access point 320, the
apparatus 2902/202). At operation 1212, the AP requests the
plurality of STAs to jointly enable the medium reserving procedure
for communication in a first time period and to jointly disable the
medium reserving procedure for communication in a second time
period. In certain configurations, within operation 1212, the AP,
at operation 1220, transmits, to the plurality of STAs, a first
time indicator indicating the first time period. At operation 1222,
the AP transmits, to the plurality of STAs, a second time indicator
indicating the second time period. At operation 1224, the AP
transmits, to the plurality of STAs, a STA indicator identifying
the each STA of the plurality of STAs. In certain configurations,
each of the first time indicator, the second time indicator, and
the STA indicator may be included in an IE of a frame or may be one
or more information bits in a frame.
[0150] For example, referring to FIG. 8, at operation 806, the
access point 320 can transmit a joined enablement request to both
the station A 302 and the station D 314. The request can be
implemented using an IE as described in FIG. 7, which may be
transmitted from the access point 320 to the station A 302 and the
station D 314 through a management frame. The access point 320 can
specify the MAC addresses of the station A 302 and the station D
314 in the group indicator field 715. The access point 320 can use
the RTS on start time field 716 and RTS on duration field 717 to
specify a first time period in which the station A 302 and the
station D 314 are requested to enable the RTS/CTS procedure. The
access point 320 can use the RTS off start time field 718 and the
RTS off duration field 719 to specify a second time period in which
the station A 302 and the station D 314 are requested to disable
the RTS/CTS procedure.
[0151] At operation 1214, the AP determines the communication
metric of the plurality of STAs in the first time period and the
communication metric of the plurality of STAs in the second time
period. In certain configurations, within operation 1214, the AP,
at operation 1230, receives data from each STA of the plurality of
STAs with joint enablement of the medium reserving procedure in the
first time period. At operation 1232, the AP determines a
respective first value of the communication metric for each STA of
the plurality of STAs based on the data received from the each STA
in the first time period. At operation 1234, the AP receives data
from each STA of the plurality of STAs with joint disablement of
the medium reserving procedure in the second time period. At
operation 1236, the AP determines a respective second value of the
communication metric for each STA of the plurality of STAs based on
the data received from the each STA in the second time period. The
improvement of the communication metric is determined based on the
first values and the second values. For example, referring to FIG.
8, at operation 871, the access point 320 can determine, using the
techniques described supra with reference to FIG. 3, the values of
one or more throughput metrics at the station A 302 and the station
D 314, respectively, in the first time period.
[0152] At operation 1216, the AP determines an improvement of the
communication metric in the first time period comparing with the
communication metric in the second time period. The communication
for the plurality of STAs is determined to be improved when the
improvement of the communication metric meets a first
threshold.
[0153] FIG. 13 is a flow chart of an exemplary method 1300 for
switching from an
[0154] RTS/CTS procedure to a polling procedure. The method may be
performed by a first STA (e.g., the station 114, the station 902,
the apparatus 3002/202). At operation 1310, the first STA sends, in
accordance with an RTS/CTS procedure, one or more RTS messages to a
second STA. At operation 1312, the first STA receives zero or more
CTS messages in response to the RTS messages from the second STA.
At operation 1314, the first STA determines a response rate based
on the RTS messages and the CTS messages. In certain
configurations, the one or more RTS messages include a first number
of RTS messages. The zero or more CTS messages include a second
number of CTS messages. The response rate is determined based on
the first number and the second number.
[0155] For example, referring to FIG. 9, in one configuration, the
station 902 is configured to determine a response rate of the
station 910. For example, the station 902 may keep a record of the
number (e.g., M) of RTSs transmitted to the station 910 and the
number (e.g., N) of CTSs received from the station 910 in response
to the RTSs. If the ratio of the number of RTSs and the number of
CTSs (e.g., N/M) is less than a predetermined ratio (e.g., 50
[0156] At operation 1316, the first STA sends a first switching
request to the second
[0157] STA when the response rate meets a threshold. The first
switching request requests the second STA to implement a polling
procedure. The polling procedure announces receiver availability
for receiving data transmission. In certain configurations, the
first switching request includes a channel load at the first STA.
For example, referring to FIG. 9, the station 902 can send to the
station 910 one or more switching requests with an observed channel
load at the station 902.
[0158] At operation 1318, the first STA receives, from the second
STA, a first switching confirmation indicating that the second STA
implements the polling procedure. For example, referring to FIG. 9,
if the channel load at the station 910 is greater than the channel
load at the station 902, the station 910 may decide to switch to
using the polling procedure for data communication with the station
902. Accordingly, the station 910 transmits a switching
confirmation to the station 902.
[0159] At operation 1320, the first STA receives a polling message
in accordance with the polling procedure. The polling message
indicates that the second STA is available for data transmission.
At operation 1322, the first STA transmits data to the second STA
in response to the polling message. For example, referring to FIG.
9, once the station 910 has determined to use a polling procedure
for data transmission between the station 902 and the station 910,
at a time point when the station 914 is not transmitting data to
the station 910 and the station 910 sense that the medium is
available, the station 910 can send a polling request to the
station 902 to announce the availability of the station 910. If the
station 902 is also available, upon receiving the polling request
from the station 910, the station 902 can start transmitting data
to the station 910.
[0160] At operation 1324, the first STA receives, from the second
STA, a second switching request requesting the first STA to
implement the RTS/CTS procedure. The second switching request
includes a channel load at the second STA. At operation 1326, the
first STA determines that a difference between the channel load at
the second STA and a channel load at the first STA meets a
threshold. At operation 1328, the first STA transmits, to the
second STA, a second switching confirmation indicating that the
first STA implements the RTS/CTS procedure. For example, referring
to FIG. 9, upon detecting a low polling response rate, the station
910 can send to the station 902 one or more switching requests with
an observed channel load at the station 910. The switching request
requests the station 902 to confirm switching to using an RTS/CTS
procedure to transmit data between the station 902 and the station
910. Upon receiving a switching request, the station 902 may
compare the channel load at the station 902 and the channel load at
the station 910. If the channel load at the station 902 is greater
than the channel load at the station 910, the station 902 can
decide to switch to using the RTS procedure for data communication
with the station 910. Accordingly, the station 902 transmits a
switching confirmation to the station 910. The switching
confirmation can be embedded in an IE in a management frame or a
data frame.
[0161] FIG. 14 is a flowchart 1400 of a method of wireless
communication for jointly enabling a medium reserving procedure. In
one configuration and optionally, at operation 1402, an AP
transmits a capability indicator indicating a capability of the AP
to request two or more STAs to jointly use the medium reserving
procedure to transmit data to the AP; the medium reserving
procedure reserves a medium for data transmission. The medium
reserving procedure can employ an RTS/CTS procedure. In one
configuration and optionally, at operation 1404, the AP transmits a
report indicator that requests a STA to report a throughput metric
to the AP in a measurement period specified in the indicator. In
one configuration and optionally, at operation 1406, the AP
initiates an evaluation procedure with first and second STAs. The
evaluation procedure determines an evaluation result associated
with throughput of respective data communications between the AP
and the first STA and the second STA jointly using the medium
reserving procedure. In one configuration and optionally, at
operation 1408, the AP determines whether the medium reserving
procedure improves the throughput based on the evaluation
result.
[0162] If the medium reserving procedure improves the throughput,
at operation 1410, the AP requests the first and second STAs to
jointly use the medium reserving procedure to transmit data to the
AP. If the medium reserving procedure does not improve the
throughput, at operation 1412, the procedure of the AP ends and the
AP operates without requesting the first and second STAs to enable
the medium reserving procedure.
[0163] In one configuration and optionally, within operation 1410,
the AP transmits, at operation 1414, a first STA indicator
identifying the first STA to instruct the first STA to use the
medium reserving procedure to transmit data to the AP. The AP
transmits a second STA indicator identifying the second STA to
instruct the second STA to use the medium reserving procedure to
transmit data to the AP. In one configuration and optionally, the
first STA indicator and the second STA indicator are included in an
IE of a frame. In one configuration and optionally, within
operation 1410, the AP transmits, at operation 1414, a first time
indicator indicating the first time period to transmit data to the
AP using the medium reserving procedure. In one configuration and
optionally, the AP transmits a second time indicator indicating the
second time period to transmit data to the AP without using the
medium reserving procedure.
[0164] In one configuration and optionally, subsequent to operation
1402, the AP receives, at operation 1405, a request from the first
STA to instruct both the first STA and the second STA to transmit
data using the medium reserving procedure. Subsequent to operation
1405, the AP executes operation 1410.
[0165] FIG. 15 is a flowchart 1500 of a method of wireless
communication for determining existence of a hidden node. In one
configuration, at operation 1502, an AP obtains an indication of a
change of a signal metric of a first data packet received from a
first STA. In one configuration, at operation 1504, the AP obtains
an indication of one or more data units in a second data packet
that have not been correctly received from the first STA. In one
configuration, at operation 1506, the AP obtains an indication of a
difference between an estimated PER and a measured PER of packets
received from the first STA. In one configuration, at operation
1508, the AP receives a report from the first STA. The report
includes an identification of a hidden STA disrupting the data
communication of the first STA. The AP identifies the first STA
based on the report.
[0166] Subsequent to the operations 1502, 1504, 1506, and 1508, the
AP determines, at operation 1510, whether a hidden STA of the first
STA exists based on the indication or the report. The hidden STA
transmits data to the AP and disrupts a data communication of the
first STA. If a hidden STA of the first STA exists, the AP enters
operation 1518. At operation 1518, the AP identifies the first STA
to jointly use the medium reserving procedure with another STA to
transmit data to the AP. At operation 1520, the AP identifies the
second STA to jointly use the medium reserving procedure with the
first STA to transmit data to the AP. If a hidden STA of the first
STA does not exist, at operation 1512, the procedure of the AP
ends.
[0167] FIG. 16 is a flowchart 1600 of a method of wireless
communication for determining interference. At operation 1602, an
AP receives a data packet from a STA. At operation 1606, the AP
obtains a first value of a signal metric at a first position of the
data packet. The signal metric can include at least one of an RSSI,
an estimated channel coefficient, an estimated phase offset, an
estimated frequency offset, or a measured pilot error vector
magnitude. At operation 1610, the AP obtains a second value of the
signal metric at a second position of the data packet. At operation
1614, the AP evaluates the first value and the second value to
determine interference.
[0168] FIG. 17 is a flowchart 1700 of a method of wireless
communication for jointly enabling a medium reserving procedure at
all receiving stations. At operation 1702, an AP identifies a
plurality of STAs from each of which interference exists at of the
AP in data reception. At operation 1706, the AP determines whether
a ratio of the plurality of STAs with respect to STAs in
communication with the AP is greater than a predetermined
threshold. If the ratio is greater than the predetermined
threshold, the AP, at operation 1710, transmits a common STA
indicator that instructs the STAs in communication with the AP each
to jointly use the medium reserving procedure to transmit data to
the AP. If the ratio is not greater than the predetermined
threshold, at operation 1714, the procedure of the AP ends and the
AP operates without requesting the STAs to enable the medium
reserving procedure.
[0169] FIG. 18 is a flowchart 1800 of a method of wireless
communication for evaluating whether using a medium reserving
procedure can improve throughput. At operation 1802, an AP receives
data from the first STA and the second STA jointly using the medium
reserving procedure in a first time period. At operation 1806, the
AP determines first values of a throughput metric of the data
received, respectively, from the first and second STAs in the first
time period. At operation 1810, the AP receives data from the first
STA and the second STA without using the medium reserving procedure
in a second time period. At operation 1814, the AP determines
second values of the throughput metric of the data received,
respectively, from the first and second STAs, respectively, in the
second time period. At operation 1818, the AP determines whether
using the medium reserving procedure improves the throughput of the
first and second STAs.
[0170] If the medium reserving procedure improves the throughput,
the AP, at operation 1822, requests the first and second STAs to
jointly use the medium reserving procedure to transmit data to the
AP. If the medium reserving procedure does not improve the
throughput, at operation 1826, the procedure of the AP ends and the
AP operates without requesting the first and second STAs to enable
the medium reserving procedure.
[0171] FIG. 19 is a flowchart 1900 of a method of wireless
communication for determining existence of a hidden node. At
operation 1902, a STA receives an acknowledgment from an AP. The
acknowledgment acknowledges receipt of a data packet. In one
configuration and optionally, at operation 1906, the STA detects an
indication in the acknowledgment. The indication indicates that the
data packet was received at the AP at the predetermined time period
prior to sending the acknowledgment.
[0172] At operation 1910, the STA determines whether the data
packet was received at the predetermined time period prior to
receiving the acknowledgment. If the data packet was not received,
the STA, at operation 1914, obtains a source identification and a
destination identification from the acknowledgment. The source
identification is associated with the AP. The destination
identification is associated with a second STA.
[0173] At operation 1918, the STA sends a request to the AP. The
request requests the AP to instruct both the first STA and the
second STA to transmit data using a medium reserving procedure, and
the medium reserving procedure reserves a medium for data
transmission. If at operation 1910 the STA determines that the data
packet was received, at operation 1912, the procedure of the STA
ends.
[0174] FIG. 20 is a flowchart 2000 of a method of wireless
communication for jointly enabling a medium reserving procedure at
a station. In one configuration and optionally, at operation 2002,
a STA transmits a capability indicator indicating a capability of
the STA to jointly use the medium reserving procedure with another
STA. In one configuration and optionally, the STA indicator is
included in an IE of a frame,
[0175] At operation 2006, the STA receives the frame. In one
configuration and optionally, at operation 2010, the STA detects
whether the STA indicator is present in the IE. If the STA
indicator is present, the STA executes operation 2014. If the STA
indicator is not present, at operation 2022, the procedure of the
STA ends.
[0176] At operation 2014, the STA determines whether the STA
indicator identifies the STA. If the STA indicator identifies the
STA, at operation 2018, the STA transmits data to the AP using a
medium reserving procedure, and the medium reserving procedure
reserves a medium for data transmission. If the STA indicator does
not identify the STA, at operation 2022, the procedure of the STA
ends.
[0177] FIG. 21 is a flowchart 2100 of a method of wireless
communication for determining whether to enable a medium reserving
procedure based on signal metrics. At operation 2102, a STA
initiates a procedure to obtain an indication of a change of a
signal metric of a first data packet received at a second STA. In
one configuration and optionally, the signal metric includes at
least one of RSSI, an estimated channel coefficient, an estimated
phase offset, an estimated frequency offset, or a measured pilot
error vector magnitude. At operation 2106, the STA obtains a first
value of the signal metric at a first position of the first data
packet. At operation 2110, the STA obtains a second value of the
signal metric at a second position of the first data packet. At
operation 2114, the STA determines the change of the signal metric
based on the first value and the second value. At operation 2118,
the STA determines whether the change is greater than a
predetermined threshold. If the change is greater, at operation
2122, the STA transmits data to the second STA using a medium
reserving procedure, and the medium reserving procedure reserves a
medium for data transmission. If the change is not greater, at
operation 2126, the procedure of the STA ends. In one
configuration, the medium reserving procedure employs an RTS/CTS
procedure.
[0178] FIG. 22 is a flowchart 2200 of a method of wireless
communication for determining whether to enable a medium reserving
procedure based on data units that have not been correctly received
at a station. At operation 2202, a STA initiates a procedure to
obtain an indication of one or more data units in a data packet
that have not been correctly received at the second STA. At
operation 2206, the STA transmits the data packet including at
least one data unit to the second STA. At operation 2210, the STA
receives an acknowledgment from the second STA. The acknowledgment
includes the indication of the one or more data units of the at
least one data unit that have not been correctly received at the
second STA. At operation 2214, the STA determines whether the
number or a ratio of the data units that have not been correctly
received at the second STA is greater than a predetermined
threshold. The STA can also determine whether a distribution of the
data units that have not been correctly received at the second STA
matches a predetermined pattern. If the number or a ratio is
greater or if distribution matches the predetermined pattern, at
operation 2218, the STA transmits data to the second STA using a
medium reserving procedure, and the medium reserving procedure
reserves a medium for data transmission. In one configuration, the
medium reserving procedure employs an RTS/CTS procedure. If the
number or a ratio is not greater or if distribution does not match
the predetermined pattern, at operation 2222, the procedure of the
STA ends. In one configuration, the second data packet is a PPDU.
The at least one data unit includes MPDUs. The acknowledgment is a
block acknowledgment.
[0179] FIG. 23 is a flowchart 2300 of a method of wireless
communication for determining whether to enable a medium reserving
procedure based on PERs. At operation 2302, a STA initiates a
procedure to obtain an indication of a difference between an
estimated PER and a measured PER at the second STA. At operation
2306, the STA transmits a plurality of data packets to the second
STA. At operation 2310, the STA determines the measured PER by
measuring a PER of the plurality of data packets. At operation
2314, the STA receives an RSSI from the second STA. At operation
2318, the STA determines the SNR based on the RSSI. At operation
2322, the STA estimates a PER based on the SNR between the first
STA and the second STA. At operation 2326, the STA determines the
difference based on the measured PER and the estimated PER. At
operation 2330, the STA determines whether the difference is
greater than a predetermined threshold. If the difference is
greater, at operation 2334, the STA transmits data to the second
STA using a medium reserving procedure, and the medium reserving
procedure reserves a medium for data transmission. In one
configuration, the medium reserving procedure employs an RTS/CTS
procedure. If the difference is greater, at operation 2338, the
procedure of the STA ends.
[0180] FIG. 24 is a flowchart 2400 of a method of wireless
communication for evaluating whether using a medium reserving
procedure can improve throughput. At operation 2402, a STA
initiates an evaluation procedure with the second STA. The
evaluation procedure determines an evaluation result associated
with a throughput of a data communication between the first STA and
the second STA using the medium reserving procedure. At operation
2406, the STA transmits first data to the second STA using the
medium reserving procedure in a first time period. At operation
2410, the STA determines a first value of a throughput metric of
the transmitted first data. In one configuration, the throughput
metric is based on an actual throughput determined at one or more
of the first STA or the second STA. In one configuration, the
throughput metric is based on an equivalent full buffer throughput
determined at the first STA. At operation 2414, the STA transmits
second data to the second STA without using the medium reserving
procedure in a second time period. At operation 2418, the STA
determines a second value of the throughput metric of the
transmitted second data. At operation 2422, the STA determines the
evaluation result based on the first and second values. At
operation 2426, the STA determines whether using the medium
reserving procedure improves the throughput of the STA based on the
evaluation result. In one configuration, the medium reserving
procedure employs an RTS/CTS procedure. If the medium reserving
procedure improves the throughput, the STA, at operation 2430, use
the medium reserving procedure to transmit data to the second STA.
If the medium reserving procedure does not improve the throughput,
at operation 2434, the STA transmits data to the second STA without
using the medium reserving procedure.
[0181] FIG. 25 is a flowchart 2500 of a method of wireless
communication for using an enhanced medium reserving procedure. At
operation 2502, the STA transmits data packets to another STA using
a medium reserving procedure, and the medium reserving procedure
reserves a medium for data transmission. In one configuration, the
medium reserving procedure employs an RTS/CTS procedure. At
operation 2506, the STA determines a measurement with respect to
occurrences of interference to the transmitted data packets. At
operation 2510, the STA determines whether the measurement is
greater than a predetermined threshold. If the measurement is not
greater, at operation 2514, the procedure of the STA ends. If the
measurement is greater, at operation 2518, the STA initiates an
enhancement procedure that reduces the occurrences of interference
to the transmitted data packets. In one configuration, subsequent
to operation 2518, the STA transmits, at operation 2522, a request
requesting a receiving STA to reduce an OTA medium occupancy of the
receiving STA. In one configuration and optionally, the request
instructs the receiving STA to adjust an EDCA parameter. In one
configuration and optionally, the request instructs the receiving
STA to maintain one or more silence periods. In one configuration
and optionally, the one or more silence periods include at least
three silence periods and are periodic.
[0182] In one configuration, subsequent to operation 2518, the STA
transmits, at operation 2532, in a repeating pattern a request in
accordance with the medium reserving procedure to the another STA.
At operation 2536, the STA receives in a repeating pattern a
response in accordance with the medium reserving procedure from the
another STA. In one configuration and optionally, both the request
is transmitted and the response is received in the respective
repeating pattern.
[0183] In one configuration, subsequent to operation 2518, the STA
transmits, at operation 2542, a first power indicator in a request
in accordance with the medium reserving procedure to the another
STA. The first power indicator indicates a transmission power to be
used at the another STA to transmit a response in accordance with
the medium reserving procedure to the STA. At operation 2546, the
STA receives a second power indicator in the response from the
another STA. The second power indicator indicates a transmission
power to be used at the STA to transmit another request in
accordance with the medium reserving procedure to the another
STA.
[0184] FIG. 26 is a flowchart 2600 of a method of wireless
communication for transiting requests/responses of a medium
reserving procedure at different data rates. At operation 2602, a
STA transmits a first request in accordance with a medium reserving
procedure at a first data rate, and the medium reserving procedure
reserves a medium for data transmission. At operation 2606, the STA
transmits data packets to another STA At operation 2610, the STA
determines a measurement with respect to occurrences of
interference to the transmitted data packets. At operation 2614,
the STA determines whether the measurement is greater than a
predetermined threshold. If the measurement is not greater than the
predetermined threshold, at operation 2618, the procedure of the
STA ends. If the measurement is greater than the predetermined
threshold, at operation 2626, the STA transmits a second request in
accordance with the medium reserving procedure at a second data
rate that is lower than the first data rate. In one configuration
and optionally, prior to operation 2626, the STA transmits, at
operation 2622, a third request in accordance with the medium
reserving procedure at the first data rate prior to transmitting
the second request in the same transmit opportunity in which the
second request is transmitted.
[0185] FIG. 27 is a flowchart 2700 of a method of wireless
communication for initiating a switching procedure. At operation
2702, a first STA initiates a data transmission with a second STA
using one of a medium reserving procedure or a polling procedure.
The medium reserving procedure reserves a medium for data
transmission. The polling procedure announces receiver availability
for receiving data transmission. At operation 2706, the first STA
communicates data with the second STA. At operation 2710, the first
STA determines a response rate of the data communication in
accordance with the one of the medium reserving procedure and the
polling procedure. At operation 2714, the first STA determines
whether the response rate is lower than a predetermined threshold.
In one configuration, the first STA transmits M requests in
accordance with the one of the medium reserving procedure and the
polling procedure to the second STA, M being an integer greater
than 1. The first STA receives N responses in accordance with the
one of the medium reserving procedure and the polling procedure
from the second STA, N being an integer greater than -1. Then the
first STA determines whether N/M is lower than a predetermined
ratio.
[0186] If the response rate is not lower, at operation 2718, the
procedure of the STA ends. If the response rate is lower, at
operation 2722, the first STA initiates a switching procedure to
allow the second STA to initiate the data transmission. At
operation 2726, the STA transmits a switching request to the second
STA. In one configuration, the switching request includes a channel
load at the first STA. At operation 2730, the STA receives a
switching confirmation from the second STA. At operation 2734, the
first STA receives a request in accordance with the other one of
the medium reserving procedure and the polling procedure.
[0187] FIG. 28 is a flowchart 2800 of a method of wireless
communication for responding to a switching procedure. At operation
2802, a first STA participates in a data transmission initiated by
the second STA using a medium reserving procedure or a polling
procedure. The medium reserving procedure reserves a medium for
data transmission. The polling procedure announces receiver
availability for receiving data transmission. At operation 2806,
the first STA communicates data with the second STA. At operation
2810, the first STA receives a switching request from the second
STA. At operation 2814, the first STA obtains a channel load at the
second STA from the switching request. At operation 2818, the first
STA obtains a channel load at the first STA. At operation 2822, the
first STA determines whether a difference between the channel load
at the first STA and the channel load at the second STA is greater
than a predetermined threshold. If the difference is not greater,
at operation 2824, the procedure of the STA ends.
[0188] If the difference is greater, the first STA, at operation
2826 transmits a switching confirmation to the second STA. At
operation 2830, the first STA initiates a data transmission at
availability of the first STA. In one configuration and optionally,
the data communication in operation 2806 uses the medium reserving
procedure. Subsequent to operation 2830, the firs STA transmits, at
operation 2834, a request in accordance with the polling procedure
to the second STA at the availability of the first STA. At
operation 2838, the first STA receives data from the second STA. In
one configuration and optionally, the data communication in
operation 2806 uses the polling procedure. Subsequent to operation
2830, the firs STA transmits, at operation 2844, a request in
accordance with the medium reserving procedure to the second STA at
the availability of the first STA. At operation 2848, the first STA
receives a response in accordance with the medium reserving
procedure from the second STA.
[0189] FIG. 29 is a conceptual data flow diagram 2900 illustrating
the data flow between different components/means in an exemplary
apparatus 2902. The apparatus 2902 may be an AP (e.g., the access
point 104, the access point 320). The apparatus 2902 includes a
reception component 2904, a transmission component 2910, a request
component 2912, a determination component 2914, and a detection
component 2916.
[0190] The apparatus 2902/202 is communication with a plurality of
STAs 2950 via the reception component 2904 and the transmission
component 2910. The reception component 2904 may receive data
packets 2932 from the plurality of STAs 2950. The detection
component 2916 may monitor the operation at the reception component
2904 and may obtain reception information 2933 regarding the data
packets 2932 from the reception component 2904. The detection
component 2916 may determine, based on the reception information
2933, that each STA of the plurality of STAs 2950 has uplink
traffic with the apparatus 2902/202. Further, the detection
component 2916 may also determine, based on the reception
information 2933, that each STA of a subset of STAs of the
plurality of STAs 2950 has a hidden node that transmits data to the
apparatus 2902/202 and disrupts a communication between the
apparatus 2902/202 and the each STA. The detection component 2916
may send such detection information 2935 to the determination
component 2914.
[0191] The determination component 2914 may decide to, based on the
detection information 2935, request a plurality of STAs 2950 to
jointly enable and disable a medium reserving procedure for
communication in order to evaluate whether the joint enablement of
the medium reserving procedure improves communication for the
plurality of STAs 2950. The determination component 2914 may make
such a decision based on at least one of that each STA of the
plurality of STAs 2950 has uplink traffic with the apparatus
2902/202 or that each STA of the subset of STAs of the plurality of
STAs 2950 has a hidden node that transmits data to the apparatus
2902/202 and disrupts a communication between the apparatus
2902/202 and the each STA. In certain configurations, the
determination component 2914 may determine, based on the detection
information 2935, that each of the plurality of STAs 2950 has a
hidden node. The plurality of STAs 2950 are requested to jointly
enable and disable the medium reserving procedure based on the
apparatus 2902/202 receiving interference from the hidden node in
association with the plurality of STAs 2950. In certain
configurations, the determination component 2914 may determine,
based on the detection information 2935, that each STA of the
subset of STAs has a hidden node that causes interference to the
apparatus 2902/202. The plurality of STAs 2950 are requested to
jointly enable and disable the medium reserving procedure based on
that the plurality of STAs 2950 each have uplink traffic and that a
ratio of the subset of STAs with respect to the plurality of STAs
2950 meets a threshold.
[0192] In certain configurations, the determination component 2914
determines that a first STA of the subset of STAs has a hidden node
when the detection component 2916 detects a change of a signal
metric during reception a data packet received from the first STA.
In certain configurations, the reception component 2904 receives
the data packets 2932 from the first STA. The detection component
2916 determines a first value of the signal metric at a first
position of the data packet. The detection component 2916 further
determines a second value of the signal metric at a second position
of the data packet. The change of the signal metric is detected
based on the first value and the second value. In certain
configurations, the signal metric includes at least one of a RSSI,
an estimated channel coefficient, an estimated phase offset, an
estimated frequency offset, or a measured pilot error vector
magnitude. In certain configurations, the determination component
2914 determines that a first STA of the subset of STAs has a hidden
node when the detection component 2916 detects that one or more
data units in a data packet from the first STA have not been
correctly received at the apparatus 2902/202. In certain
configurations, the determination component 2914 determines that a
first STA of the subset of STAs has a hidden node when the
apparatus 2902/202 detects a difference between an estimated PER
and a measured PER for packets received from the first STA. In
certain configurations, the reception component 2904 receives data
packets 2932 carrying a report from the first STA. The report
includes an identification of the hidden node of the first STA. The
determination component 2914 obtains the report from the reception
component 2904 and determines that a first STA of the subset of
STAs has a hidden node based on the report.
[0193] Accordingly, the determination component 2914 sends a
request instruction 2934 to the request component 2912. The request
component 2912 constructs a request frame 2942 and sends the
request frame 2942 to the transmission component 2910. The
transmission component 2910 transmits the request frame 2942 to the
plurality of STAs 2950. In certain configurations, the request
frame 2942 requests the plurality of STAs 2950 to jointly enable
the medium reserving procedure for communication in a first time
period and to jointly disable the medium reserving procedure for
communication in a second time period. In certain configurations,
the request frame 2942 includes a first time indicator indicating
the first time period. In certain configurations, the request frame
2942 includes a second time indicator indicating the second time
period. In certain configurations, the request frame 2942 includes
a STA indicator identifying the each STA of the plurality of STAs
2950. In certain configurations, the first time indicator, the
second time indicator, and/or the STA indicator may be included in
an IE of the request frame 2942 or is an information bit in the
request frame 2942.
[0194] The reception component 2904 may receive communication
metric information 2944 from the plurality of STAs 2950. The
communication metric information 2944 indicates a communication
metric while jointly enabling or disabling the medium reserving
procedure for communication. The reception component 2904 sends the
communication metric information 2944 to the determination
component 2914. The determination component 2914 may determine,
based on the received communication metric information 2944,
whether the joint enablement of the medium reserving procedure
improves communication for the plurality of STAs 2950. In certain
configurations, the determination component 2914 determines, based
on the received communication metric information 2944, the
communication metric of the plurality of STAs 2950 in the first
time period and the communication metric of the plurality of STAs
2950 in the second time period.
[0195] In certain configurations, the reception component 2904 may
receive data packets 2932 from each STA of the plurality of STAs
2950 with joint enablement of the medium reserving procedure in the
first time period. The detection component 2916 may determine a
respective first value of the communication metric for each STA of
the plurality of STAs 2950 based on the data packets 2932 received
from the each STA in the first time period. The reception component
2904 may receive data packets 2932 from each STA of the plurality
of STAs 2950 with joint disablement of the medium reserving
procedure in the second time period. The detection component 2916
may determine a respective second value of the communication metric
for each STA of the plurality of STAs 2950 based on the data
received from the each STA in the second time period. The detection
component 2916 sends corresponding detection information 2935 the
determination component 2914. The determination component 2914 may
determine the improvement of the communication metric based on the
first values and the second values.
[0196] The determination component 2914 may decide to request the
plurality of STAs 2950 to jointly enable the medium reserving
procedure for subsequent communication when the joint enablement of
the medium reserving procedure improves communication for the
plurality of STAs 2950. In certain configurations, the
determination component 2914 determines, based on the received
communication metric information 2944, an improvement of the
communication metric in the first time period comparing with the
communication metric in the second time period. The communication
for the plurality of STAs 2950 is determined to be improved when
the improvement of the communication metric meets a first
threshold.
[0197] Accordingly, the determination component 2914 sends a
request instruction 2934 to the request component 2912. The request
component 2912 constructs a request frame 2942 and sends the
request frame 2942 to the transmission component 2910. The
transmission component 2910 transmits the request frame 2942 to the
plurality of STAs 2950.
[0198] In certain configurations, the medium reserving procedure
employs an RTS/CTS procedure. In certain configurations, the
communication metric includes at least one of an actual throughput,
an equivalent full buffer throughput, a retry rate, a PER, a MCS,
or an access delay.
[0199] The apparatus may include additional components that perform
each of the blocks of the algorithm in the aforementioned
flowcharts of FIGS. 11-28. As such, each block in the
aforementioned flowcharts of FIGS. 11-28 may be performed by a
component and the apparatus may include one or more of those
components. The components may be one or more hardware components
specifically configured to carry out the stated
processes/algorithm, implemented by a processor configured to
perform the stated processes/algorithm, stored within a
computer-readable medium for implementation by a processor, or some
combination thereof.
[0200] The request component 2912, the determination component
2914, and the detection component 2916 may constitute the MRP
component 224 shown in FIG. 2. The request component 2912, the
determination component 2914, and the detection component 2916 may
employ the processor 204, the memory 206, the signal detector 218,
the DSP 220, and/or the user interface 222. The reception component
2904 and the transmission component 2910 may employ the processor
204, the memory 206, the signal detector 218, and/or the DSP 220.
The transceiver 214 receives a signal from the one or more antennas
216, extracts information from the received signal, and provides
the extracted information to the reception component 2904. In
addition, the transceiver 214 receives information from the
transmission component 2910, and based on the received information,
generates a signal to be applied to the one or more antennas
216.
[0201] In one aspect, the apparatus 2902/202 may be an AP. The
apparatus 2902/202 may be configured to include means for
performing the operations illustrated in FIGS. 11-28. More
specifically, the apparatus 2902/202 may be configured to include
means for requesting a plurality of STAs to jointly enable and
disable a medium reserving procedure for communication based on at
least one of that each STA of the plurality of STAs has uplink
traffic with the AP or that each STA of a subset of STAs of the
plurality of STAs has a hidden node that transmits data to the AP
and disrupts a communication between the AP and the each STA. The
apparatus 2902/202 may be configured to include means for
receiving, from the plurality of STAs, information indicating a
communication metric while jointly enabling or disabling the medium
reserving procedure for communication. The apparatus 2902/202 may
be configured to include means for determining, based on the
received information indicating the communication metric, whether
the joint enablement of the medium reserving procedure improves
communication for the plurality of STAs. The apparatus 2902/202 may
be configured to include means for requesting the plurality of STAs
to jointly enable the medium reserving procedure for subsequent
communication when the joint enablement of the medium reserving
procedure improves communication for the plurality of STAs.
[0202] In certain configurations, the apparatus 2902/202 may be
configured to include means for determining that each of the
plurality of STAs has a hidden node. The plurality of STAs are
requested to jointly enable and disable the medium reserving
procedure based on the AP receiving interference from the hidden
node in association with the plurality of STAs. In certain
configurations, the apparatus 2902/202 may be configured to include
means for determining that each STA of the subset of STAs has a
hidden node that causes interference to the AP. The plurality of
STAs are requested to jointly enable and disable the medium
reserving procedure based on that the plurality of STAs each have
uplink traffic and that a ratio of the subset of STAs with respect
to the plurality of STAs meets a threshold. In certain
configurations, the medium reserving procedure employs an RTS/CTS
procedure. In certain configurations, the communication metric
includes at least one of an actual throughput, an equivalent full
buffer throughput, a retry rate, a PER, a MCS, or an access
delay.
[0203] In certain configurations, the means for requesting the
plurality of STAs to jointly enable and disable the medium
reserving procedure is further configured to request the plurality
of STAs to jointly enable the medium reserving procedure for
communication in a first time period and to jointly disable the
medium reserving procedure for communication in a second time
period. The means for determining whether the joint enablement of
the medium reserving procedure improves communication is further
configured to determine the communication metric of the plurality
of STAs in the first time period and the communication metric of
the plurality of STAs in the second and to determine an improvement
of the communication metric in the first time period comparing with
the communication metric in the second time period. The
communication for the plurality of STAs is determined to be
improved when the improvement of the communication metric meets a
first threshold.
[0204] In certain configurations, the means for determining the
communication metric of the plurality of STAs in the first time
period and the communication metric of the plurality of STAs in the
second time period is further configured to receive data from each
STA of the plurality of STAs with joint enablement of the medium
reserving procedure in the first time period. the means for
determining the communication metric of the plurality of STAs in
the first time period and the communication metric of the plurality
of STAs in the second time period is further configured to
determine a respective first value of the communication metric for
each STA of the plurality of STAs based on the data received from
the each STA in the first time period. The means for determining
the communication metric of the plurality of STAs in the first time
period and the communication metric of the plurality of STAs in the
second time period is further configured to receive data from each
STA of the plurality of STAs with joint disablement of the medium
reserving procedure in the second time period. the means for
determining the communication metric of the plurality of STAs in
the first time period and the communication metric of the plurality
of STAs in the second time period is further configured to
determine a respective second value of the communication metric for
each STA of the plurality of STAs based on the data received from
the each STA in the second time period. The improvement of the
communication metric is determined based on the first values and
the second values.
[0205] In certain configurations, the means for requesting the
plurality of STAs to jointly enable the medium reserving procedure
for communication in the first time period and to jointly disable
the medium reserving procedure for communication in the second time
period is further configured to transmit, to the plurality of STAs,
a first time indicator indicating the first time period and to
transmit, to the plurality of STAs, a second time indicator
indicating the second time period. In certain configurations, the
apparatus 2902/202 may be configured to include means for
requesting the plurality of STAs to jointly enable the medium
reserving procedure for communication in the first time period and
to jointly disable the medium reserving procedure for communication
in the second time period is further configured to transmit, to the
plurality of STAs, a STA indicator identifying the each STA of the
plurality of STAs. In certain configurations, the STA indicator is
included in an information element (IE) of a frame or is an
information bit in a frame. In certain configurations, the
apparatus 2902/202 may be configured to include means for
determining that a first STA of the subset of STAs has a hidden
node when the AP detects a change of a signal metric during
reception a data packet received from the first STA.
[0206] In certain configurations, the apparatus 2902/202 may be
configured to include means for receiving the data packet from the
first STA. The apparatus 2902/202 may be configured to include
means for determining a first value of the signal metric at a first
position of the data packet. The apparatus 2902/202 may be
configured to include means for determining a second value of the
signal metric at a second position of the data packet. The change
of the signal metric is detected based on the first value and the
second value. In certain configurations, the signal metric includes
at least one of a RSSI, an estimated channel coefficient, an
estimated phase offset, an estimated frequency offset, or a
measured pilot error vector magnitude.
[0207] In certain configurations, the apparatus 2902/202 may be
configured to include means for determining that a first STA of the
subset of STAs has a hidden node when the AP detects that one or
more data units in a data packet from the first STA have not been
correctly received at the AP. In certain configurations, the
apparatus 2902/202 may be configured to include means for
determining that a first STA of the subset of STAs has a hidden
node when the AP detects a difference between an estimated PER and
a measured PER for packets received from the first STA. In certain
configurations, the apparatus 2902/202 may be configured to include
means for determining that a first STA of the subset of STAs has a
hidden node when the AP receives a report from the first STA. The
report includes an identification of the hidden node of the first
STA.
[0208] The aforementioned means may be one or more of the
aforementioned components of the wireless device 202/2902
configured to perform the functions recited by the aforementioned
means. The various operations of methods described above may be
performed by any suitable means capable of performing the
operations, such as various hardware and/or software component(s),
circuits, and/or module(s). Generally, any operations illustrated
in the Figures may be performed by corresponding functional means
capable of performing the operations.
[0209] FIG. 30 is a conceptual data flow diagram 3000 illustrating
the data flow between different components/means in an exemplary
apparatus 3002. The apparatus 3002 may be a first STA (e.g., the
station 114, the station 902). The apparatus 3002 includes a
reception component 3004, a transmission component 301 an RTS/CTS
component 3012, a determination component 3014, and a detection
component 3016.
[0210] The apparatus 3002/202 is communication with the STA 3050
via the reception component 3004 and the transmission component
3010. The RTS/CTS component 3012 may construct one or more RTS
messages 3042 in accordance with an RTS/CTS procedure. The RTS/CTS
component 3012 sends the RTS messages 3042 to the transmission
component 3010. The transmission component 3010 transmits the RTS
messages 3042 to the STA 3050.
[0211] The reception component 3004 may receive zero or more CTS
messages 3032 in response to the RTS messages from the STA 3050.
The reception component 3004 sends the CTS messages 3032 to the
RTS/CTS component 3012. The RTS/CTS component 3012 sends
corresponding RTS/CTS information 3034 to the determination
component 3014. The determination component 3014 may determine a
response rate based on the RTS/CTS information 3034. The
determination component 3014 sends switching information 3035 to
the detection component 3016 when the response rate meets a
threshold. The switching information 3035 indicates to request the
STA 3050 to implement a polling procedure. The polling procedure
announces receiver availability for receiving data transmission.
Accordingly, the detection component 3016 construct a corresponding
first switching request 3033 and sends the first switching request
3033 to the transmission component 3010. The transmission component
3010 transmits the first switching request 3033 to the STA 3050.
The first switching request 3033 requests the STA 3050 to implement
the polling procedure. In certain configurations, the first
switching request 3033 includes a channel load at the apparatus
3002/202.
[0212] In certain configurations, the RTS/CTS component 3012
determines that the one or more RTS messages 3042 include a first
number of RTS messages. The RTS/CTS component 3012 determines that
the CTS messages 3032 include a second number of CTS messages. The
RTS/CTS information 3034 includes information regarding the first
number and the second number. The determination component 3014
determines the response rate based on the first number and the
second number.
[0213] In certain configurations, the reception component 3004 may
receive, from the STA 3050, a first switching confirmation 3044
indicating that the STA 3050 implements the polling procedure. The
reception component 3004 sends the first switching confirmation
3044 to the detection component 3016. The detection component 3016
sends switching information 3035 indicating the confirmation to the
determination component 3014.
[0214] Subsequently, the reception component 3004 may receiving a
polling message 3046 in accordance with the polling procedure. The
polling message indicates that the STA 3050 is available for data
transmission. The reception component 3004 sends the polling
message 3046 to the determination component 3014. The determination
component 3014 sends a transmission instruction 3048 to the
reception component 2904 to instructs the reception component 2904
to transmit data 3040 to the STA 3050.
[0215] In certain configurations, the reception component 3004 may
receive, from the STA 3050, a second switching request 3037
requesting the apparatus 3002/202 to implement the RTS/CTS
procedure. The second switching request 3037 includes a channel
load at the STA 3050. The reception component 3004 sends the second
switching request 3037 to the detection component 3016. The
detection component 3016 accordingly sends switching information
3035 indicating such request to the determination component 3014.
The determination component 3014 determines that a difference
between the channel load at the STA 3050 and a channel load at the
apparatus 3002/202 meets a threshold. The determination component
3014 sends to the detection component 3016 switching information
3035 indicating a confirmation of the request. The detection
component 3016 constructs a corresponding second switching
confirmation 3038 and send the second switching confirmation 3038
to the reception component 3004. The reception component 3004
transmits, to the STA 3050, the second switching confirmation 3038
indicating that the apparatus 3002/202 implements the RTS/CTS
procedure.
[0216] The apparatus may include additional components that perform
each of the blocks of the algorithm in the aforementioned
flowcharts of FIGS. 11-28. As such, each block in the
aforementioned flowcharts of FIGS. 11-28 may be performed by a
component and the apparatus may include one or more of those
components. The components may be one or more hardware components
specifically configured to carry out the stated
processes/algorithm, implemented by a processor configured to
perform the stated processes/algorithm, stored within a
computer-readable medium for implementation by a processor, or some
combination thereof.
[0217] The RTS/CTS component 3012, the determination component
3014, and the detection component 3016 may constitute the MRP
component 224 shown in FIG. 2. The RTS/CTS component 3012, the
determination component 3014, and the detection component 3016 may
employ the processor 204, the memory 206, the signal detector 218,
the DSP 220, and/or the user interface 222. The reception component
3004 and the transmission component 3010 may employ the processor
204, the memory 206, the signal detector 218, and/or the DSP 220.
The transceiver 214 receives a signal from the one or more antennas
216, extracts information from the received signal, and provides
the extracted information to the reception component 3004. In
addition, the transceiver 214 receives information from the
transmission component 3010, and based on the received information,
generates a signal to be applied to the one or more antennas
216.
[0218] In one aspect, the apparatus 3002/202 may be a first STA.
The apparatus 3002/202 may be configured to include means for
performing the operations illustrated in FIGS. 11-28. More
specifically, the apparatus 3002/202 may be configured to include
means for sending, in accordance with the RTS/CTS procedure, one or
more RTS messages to a second STA. The apparatus 3002/202 may be
configured to include means for receiving zero or more CTS messages
in response to the RTS messages from the second STA. The apparatus
3002/202 may be configured to include means for determining a
response rate based on the RTS messages and the CTS messages. The
apparatus 3002/202 may be configured to include means for sending a
first switching request to the second STA when the response rate
meets a threshold, the first switching request requesting the
second STA to implement a polling procedure, the polling procedure
announcing receiver availability for receiving data
transmission.
[0219] In certain configurations, the first switching request
includes a channel load at the first STA. In certain
configurations, the one or more RTS messages include a first number
of RTS messages. The zero or more CTS messages include a second
number of CTS messages. The response rate is determined based on
the first number and the second number.
[0220] In certain configurations, the apparatus 3002/202 may be
configured to include means for receiving, from the second STA, a
first switching confirmation indicating that the second STA
implements the polling procedure. The apparatus 3002/202 may be
configured to include means for receiving a polling message in
accordance with the polling procedure. The polling message
indicates that the second STA is available for data transmission.
The apparatus 3002/202 may be configured to include means for
transmitting data to the second STA in response to the polling
message.
[0221] In certain configurations, the apparatus 3002/202 may be
configured to include means for receiving, from the second STA, a
second switching request requesting the first STA to implement the
RTS/CTS procedure. The second switching request includes a channel
load at the second STA. The apparatus 3002/202 may be configured to
include means for determining that a difference between the channel
load at the second STA and a channel load at the first STA meets a
threshold. The apparatus 3002/202 may be configured to include
means for transmitting, to the second STA, a second switching
confirmation indicating that the first STA implements the RTS/CTS
procedure.
[0222] The aforementioned means may be one or more of the
aforementioned components of the wireless device 202/3002
configured to perform the functions recited by the aforementioned
means. The various operations of methods described above may be
performed by any suitable means capable of performing the
operations, such as various hardware and/or software component(s),
circuits, and/or module(s). Generally, any operations illustrated
in the Figures may be performed by corresponding functional means
capable of performing the operations.
[0223] FIG. 31 is a functional block diagram 3100 of an example
wireless communication device 3102. The wireless communication
device 3102 may include a receiver 3105, a processing system 3110,
and a transmitter 3115.
[0224] In one configuration, the wireless communication device 3102
is an AP. The receiver 3105, the processing system 3110, and/or the
transmitter 3115 may be configured to request first and second STAs
to jointly use a medium reserving procedure to transmit data to the
AP. The medium reserving procedure reserves a medium for data
transmission. The medium reserving procedure may employ an RTS/CTS
procedure.
[0225] The processing system 3110 and/or the transmitter 3115 may
be configured to transmit a first STA indicator identifying the
first STA to instruct the first STA to use the medium reserving
procedure to transmit data to the AP. The processing system 3110
and/or the transmitter 3115 may be configured to transmit a second
STA indicator identifying the second STA to instruct the second STA
to use the medium reserving procedure to transmit data to the AP.
The first STA indicator and the second STA indicator may be
included in an IE of a frame.
[0226] The processing system 3110 and/or the transmitter 3115 may
be configured to transmit a first time indicator specifying the
first time period to transmit data to the AP using the medium
reserving procedure. The processing system 3110 and/or the
transmitter 3115 may be configured to selectively transmit a second
time indicator specifying the second time period to transmit data
to the AP without using the medium reserving procedure. The
processing system 3110 and/or the transmitter 3115 may be
configured to transmit a common STA indicator that instructs all
receiving STAs to jointly use the medium reserving procedure to
transmit data to the AP.
[0227] The processing system 3110 may be configured to identify a
plurality of STAs from each of which interference exists at of the
AP in data reception. The processing system 3110 may be configured
to determine whether a ratio of the plurality of STAs with respect
to STAs in communication with the AP is greater than a
predetermined threshold. The common STA indicator is transmitted in
response to determining that the ratio is greater than the
predetermined threshold.
[0228] The processing system 3110 and/or the transmitter 3115 may
be configured to transmit a capability indicator indicating a
capability of the AP to request two or more STAs to jointly use the
medium reserving procedure to transmit data to the AP. The
processing system 3110 and/or the transmitter 3115 may be
configured to transmit a report indicator that requests a STA to
report a throughput metric to the AP in a measurement period
specified in the indicator. The receiver 3105 and/or the processing
system 3110 may be configured to receive a request from the first
STA to instruct both the first STA and the second STA to transmit
data using the medium reserving procedure.
[0229] The processing system 3110 may be configured to identify the
first STA from which interference exists at the AP in data
reception. The processing system 3110 may be configured to identify
the second STA to jointly use the medium reserving procedure with
the first STA to transmit data to the AP. To identify the first
STA, the processing system 3110 may be configured to determine
whether a hidden STA of the first STA exists. The hidden STA
transmits data to the AP and disrupts a data communication of the
first STA.
[0230] To determine whether the hidden STA of the first STA exists,
the receiver 3105, the processing system 3110, and/or the
transmitter 3115 may be configured to obtain an indication of at
least one of a change of a signal metric of a first data packet
received from the first STA, one or more data units in a second
data packet that have not been correctly received from the first
STA, or a difference between an estimated PER and a measured PER of
packets received from the first STA. The processing system 3110 may
be configured to determine whether the hidden STA of the first STA
exists based on the indication. To determine whether the hidden STA
of the first STA exists, receiver 3105 and/or the processing system
3110 may be configured to receive a report from the first STA. The
report includes an identification of a hidden STA disrupting the
data communication of the first STA. The AP identifies the first
STA based on the report.
[0231] To determining whether the hidden STA of the first STA
exists, the receiver 3105 and/or the processing system 3110 may be
configured to receive a first data packet from the first STA. The
receiver 3105 and/or the processing system 3110 may be configured
to obtain a first value of a signal metric at a first position of
the first data packet. The receiver 3105 and/or the processing
system 3110 may be configured to obtain a second value of the
signal metric at a second position of the first data packet. The
processing system 3110 may be configured to evaluate the first
value and the second value. The signal metric may include at least
one of an RSSI, an estimated channel coefficient, an estimated
phase offset, an estimated frequency offset, or a measured pilot
error vector magnitude.
[0232] The receiver 3105, the processing system 3110, and/or the
transmitter 3115 may be configured to initiate an evaluation
procedure with the first and second STAs. The evaluation procedure
determines an evaluation result associated with throughputs of
respective data communications between the AP and the first STA and
the second STA jointly using the medium reserving procedure. The
requesting first and second STAs is executed in response to the
evaluation result. To execute the evaluation procedure, the
receiver 3105 and/or the processing system 3110 may be configured
to receive data from the first STA and the second STA jointly using
the medium reserving procedure in a first time period. The receiver
3105 and/or the processing system 3110 may be configured to
determine first values of a throughput metric of the data received,
respectively, from the first and second STAs in the first time
period. The receiver 3105 and/or the processing system 3110 may be
configured to receive data from the first STA and the second STA
without using the medium reserving procedure in a second time
period. The processing system 3110 may be configured to determine
second values of the throughput metric of the data received,
respectively, from the first and second STAs, respectively, in the
second time period. The processing system 3110 may be configured to
determine the evaluation result based on the first values and the
second values.
[0233] In one configuration, the wireless communication device 3102
is a STA. The receiver 3105 and/or the processing system 3110 may
be configured to receive an acknowledgment from an AP. The
acknowledgment acknowledges receipt of a data packet. The receiver
3105 and/or the processing system 3110 may be configured to
determine whether the data packet was received at the first STA at
a predetermined time period prior to receiving the acknowledgment.
In response to determining that the data packet was not received,
the processing system 3110 may be configured to obtain a source
identification and a destination identification from the
acknowledgment. The source identification is associated with the
AP. The destination identification is associated with a second STA.
The processing system 3110 and/or the transmitter 3115 may be
configured to send a request to the AP. The request requests the AP
to instruct both the first STA and the second STA to transmit data
using a medium reserving procedure. The medium reserving procedure
reserves a medium for data transmission.
[0234] The receiver 3105 and/or the processing system 3110 may be
configured to detect an indication in the acknowledgment. The
indication indicates that the data packet was received at the AP at
the predetermined time period prior to sending the acknowledgment.
The determining whether the data packet was received is executed in
response to detecting the indication.
[0235] In one configuration, the wireless communication device 3102
is a STA. The receiver 3105 and/or the processing system 3110 may
be configured to receive a STA indicator from an AP. The processing
system 3110 may be configured to determine whether the STA
indicator identifies the STA. In response to determining that the
STA indicator identifies the STA, the processing system 3110 and/or
the transmitter 3115 may be configured to transmit data to the AP
using a medium reserving procedure. The medium reserving procedure
reserves a medium for data transmission. The STA indicator may be
included in an IE of a frame. The receiver 3105 and/or the
processing system 3110 may be configured to receiving the frame and
to detect whether the STA indicator is present in the IE. The
processing system 3110 and/or the transmitter 3115 may be
configured to transmit a capability indicator indicating a
capability of the STA to jointly use the medium reserving procedure
with another STA.
[0236] In one configuration, the wireless communication device 3102
is a STA. The receiver 3105, the processing system 3110, and/or the
transmitter 3115 may be configured to obtain an indication of at
least one of a change of a signal metric of a first data packet
received at a second STA, one or more data units in a second data
packet that have not been correctly received at the second STA, or
a difference between an estimated PER and a measured PER at the
second STA. The processing system 3110 may be configured to
determine whether to transmit data to the second STA using a medium
reserving procedure based on the indication. The medium reserving
procedure reserves a medium for data transmission. The medium
reserving procedure may employ an RTS/CTS procedure.
[0237] The processing system 3110 may be configured to determine
whether to initiate an evaluation procedure with the second STA
based on the indication. The evaluation procedure determines an
evaluation result associated with a throughput of a data
communication between the first STA and the second STA using the
medium reserving procedure. The determining whether to transmit
data is executed in response to the evaluation result. To execute
the evaluation procedure, the processing system 3110 and/or the
transmitter 3115 may be configured to transmit first data to the
second STA using the medium reserving procedure in a first time
period. The processing system 3110 may be configured to determine a
first value of a throughput metric of the transmitted first data.
The processing system 3110 and/or the transmitter 3115 may be
configured to may transmit second data to the second STA without
using the medium reserving procedure in a second time period. The
processing system 3110 may be configured to determine a second
value of the throughput metric of the transmitted second data. The
processing system 3110 may be configured to determine the
evaluation result based on the first and second values. The
throughput metric may be based on an actual throughput determined
at one or more of the first STA or the second STA. The throughput
metric may be based on an equivalent full buffer throughput
determined at the first STA.
[0238] To obtain the indication of the change of the signal metric,
the receiver 3105 and/or the processing system 3110 may be
configured to obtain a first value of the signal metric at a first
position of the first data packet. The receiver 3105 and/or the
processing system 3110 may be configured to may obtain a second
value of the signal metric at a second position of the first data
packet. The processing system 3110 may be configured to may
determine the change of the signal metric based on the first value
and the second value. The signal metric may include at least one of
an RSSI, an estimated channel coefficient, an estimated phase
offset, an estimated frequency offset, or a measured pilot error
vector magnitude.
[0239] To obtain the indication of the one or more data units, the
processing system 3110 and/or the transmitter 3115 may be
configured to transmit the second data packet including at least
one data unit to the second STA. The receiver 3105 and/or the
processing system 3110 may be configured to receive an
acknowledgment from the second STA. The acknowledgment includes the
indication of the one or more data units of the at least one data
unit that have not been correctly received at the second STA. The
second data packet may include a PPDU. The at least one data unit
may include a plurality of MPDUs. The acknowledgment may be a block
acknowledgment. The indication may indicate MPDUs of the plurality
of MPDUs that have been correctly received at the second STA and
MPDUs of the plurality of MPDUs that have not been correctly
received at the second STA. The determining to initiate the
evaluation procedure may be based on the number, a ratio, or a
distribution of MPDUs that have not been correctly received at the
second STA.
[0240] To obtain the indication of the difference between the
estimated PER and a measured PER, the processing system 3110 and/or
the transmitter 3115 may be configured to transmit a plurality of
data packets to the second STA. The receiver 3105 and/or the
processing system 3110 may be configured to determine the measured
PER by measuring a PER of the plurality of data packets. The
processing system 3110 may be configured to determine the estimated
PER by estimating a PER based on a signal and noise indicator
between the first STA and the second STA. The processing system
3110 may be configured to determine the difference based on the
measured PER and the estimated PER. The signal and noise indicator
is a signal-to-noise ratio. To estimate the PER, the receiver 3105
and/or the processing system 3110 may be configured to receive an
RSSI from the second STA. The processing system 3110 may be
configured to determine the signal-to-noise ratio based on the
RSSI.
[0241] In one configuration, the wireless communication device 3102
is a STA. The processing system 3110 and/or the transmitter 3115
may be configured to transmit data packets to another STA using a
medium reserving procedure. The medium reserving procedure reserves
a medium for data transmission. The receiver 3105, the processing
system 3110, and/or the transmitter 3115 may be configured to
determine a measurement with respect to occurrences of interference
to the transmitted data packets. The processing system 3110 may be
configured to determine whether the measurement is greater than a
predetermined threshold. In response to determining that the
measurement is greater than the predetermined threshold, the
receiver 3105, the processing system 3110, and/or the transmitter
3115 may be configured to initiate an enhancement procedure that
reduces the occurrences of interference to the transmitted data
packets. The medium reserving procedure may employ an RTS/CTS
procedure.
[0242] To execute the enhancement procedure, the processing system
3110 and/or the transmitter 3115 may be configured to transmit a
request requesting a receiving STA to reduce an OTA medium
occupancy of the receiving STA. The request may instruct the
receiving STA to adjust an EDCA parameter. The request may instruct
the receiving STA to maintain one or more silence periods. The one
or more silence periods may include at least three silence periods
and may be periodic.
[0243] To execute the enhancement procedure, the processing system
3110 and/or the transmitter 3115 may be configured to transmit in a
repeating pattern a request in accordance with the medium reserving
procedure to the another STA. The medium reserving procedure
reserves a medium for data transmission. The receiver 3105 and/or
the processing system 3110 may be configured to receive in a
repeating pattern a response in accordance with the medium
reserving procedure from the another STA. The medium reserving
procedure may employ an RTS/CTS procedure. Both the request may be
transmitted and the response is received in the respective
repeating pattern.
[0244] To execute the enhancement procedure, the processing system
3110 and/or the transmitter 3115 may be configured to transmit a
first power indicator in a request in accordance with a medium
reserving procedure to the another STA. The first power indicator
indicates a transmission power to be used at the another STA to
transmit a response in accordance with the medium reserving
procedure to the STA. The receiver 3105 and/or the processing
system 3110 may be configured to receive a second power indicator
in the response from the another STA. The second power indicator
indicates a transmission power to be used at the STA to transmit
another request in accordance with the medium reserving procedure
to the another STA.
[0245] The transmitting data packets to the another STA using the
medium reserving procedure may include transmitting a first request
in accordance with the medium reserving procedure at a first data
rate. To execute the enhancement procedure, the processing system
3110 and/or the transmitter 3115 may be configured to transmit a
second request in accordance with the medium reserving procedure at
a second data rate that is lower than the first data rate. The
processing system 3110 and/or the transmitter 3115 may be
configured to transmit a third request in accordance with the
medium reserving procedure at the first data rate prior to
transmitting the second request in a same transmit opportunity in
which the second request is transmitted.
[0246] In one configuration, the wireless communication device 3102
is a first STA. The receiver 3105, the processing system 3110,
and/or the transmitter 3115 may be configured to communicate data
with a second STA using one of a medium reserving procedure or a
polling procedure. In the one of the medium reserving procedure or
the polling procedure, the receiver 3105, the processing system
3110, and/or the transmitter 3115 may be configured to initiate a
data transmission. The medium reserving procedure reserves a medium
for data transmission. The polling procedure announces receiver
availability for receiving data transmission. The receiver 3105,
the processing system 3110, and/or the transmitter 3115 may be
configured to initiate a switching procedure to allow the second
STA to initiate the data transmission.
[0247] The processing system 3110 may be configured to determine a
response rate of the data communication in accordance with the one
of the medium reserving procedure and the polling procedure. The
switching procedure is initiated in response to the response rate.
To determine the response rate, the processing system 3110 and/or
the transmitter 3115 may be configured to transmit M requests in
accordance with the one of the medium reserving procedure and the
polling procedure to the second STA, M being an integer greater
than 1. The receiver 3105 and/or the processing system 3110 may be
configured to receive N responses in accordance with the one of the
medium reserving procedure and the polling procedure from the
second STA, N being an integer greater than -1. The processing
system 3110 may be configured to determine whether N/M is lower
than a predetermined ratio.
[0248] To execute the switching procedure, the processing system
3110 and/or the transmitter 3115 may be configured to transmit a
switching request to the second STA. The receiver 3105 and/or the
processing system 3110 may be configured to receive a switching
confirmation from the second STA. The receiver 3105 and/or the
processing system 3110 may be configured to receive a request in
accordance with the other one of the medium reserving procedure and
the polling procedure. The switching request may include a channel
load at the first STA.
[0249] In one configuration, the wireless communication device 3102
is a first STA.
[0250] The receiver 3105, the processing system 3110, and/or the
transmitter 3115 may be configured to communicate with a second STA
using a medium reserving procedure or a polling procedure. In the
medium reserving procedure or the polling procedure, the receiver
3105, the processing system 3110, and/or the transmitter 3115 may
be configured to participate in a data transmission initiated by
the second STA. The medium reserving procedure reserves a medium
for data transmission. The polling procedure announces receiver
availability for receiving data transmission. The receiver 3105
and/or the processing system 3110 may be configured to receive a
switching request from the second STA. The processing system 3110
and/or the transmitter 3115 may be configured to transmit a
switching confirmation to the second STA. The receiver 3105, the
processing system 3110, and/or the transmitter 3115 may be
configured to initiate a data transmission at availability of the
first STA. The switching request may include a channel load at the
second STA. The processing system 3110 may be configured to
determine whether a difference between a channel load at the first
STA and the channel load at the second STA is greater than a
predetermined threshold. The switching confirmation is transmitted
and the data transmission is initiated in response to determining
that the difference is greater than the predetermined
threshold.
[0251] The data communication may use the medium reserving
procedure. To initiate the data transmission, the processing system
3110 and/or the transmitter 3115 may be configured to transmit a
request in accordance with the polling procedure to the second STA
at the availability of the first STA. The receiver 3105 and/or the
processing system 3110 may be configured to receive data from the
second STA.
[0252] The data communication may use the polling procedure. To
initiate the data transmission, the processing system 3110 and/or
the transmitter 3115 may be configured to transmit a request in
accordance with the medium reserving procedure to the second STA at
the availability of the first STA. The receiver 3105 and/or the
processing system 3110 may be configured to receive a response in
accordance with the medium reserving procedure from the second
STA.
[0253] Moreover, means for execute all the operations described
supra with reference to FIGS. 11-28 may comprise the processing
system 3110, the receiver 3105, and/or the transmitter 3115.
[0254] The various operations of methods described above may be
performed by any suitable means capable of performing the
operations, such as various hardware and/or software component(s),
circuits, and/or module(s). Generally, any operations illustrated
in the Figures may be performed by corresponding functional means
capable of performing the operations.
[0255] The various illustrative logical blocks, modules and
circuits described in connection with the present disclosure may be
implemented or performed with a general purpose processor, a
digital signal processor (DSP), an application specific integrated
circuit (ASIC), a field programmable gate array signal (FPGA) or
other programmable logic device (PLD), discrete gate or transistor
logic, discrete hardware components or any combination thereof
designed to perform the functions described herein. A general
purpose processor may be a microprocessor, but in the alternative,
the processor may be any commercially available processor,
controller, microcontroller or state machine. A processor may also
be implemented as a combination of computing devices, e.g., a
combination of a DSP and a microprocessor, a plurality of
microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other such configuration.
[0256] In one or more aspects, the functions described may be
implemented in hardware, software, firmware, or any combination
thereof. If implemented in software, the functions may be stored on
or transmitted over as one or more instructions or code on a
computer-readable medium. Computer-readable media includes both
computer storage media and communication media including any medium
that facilitates transfer of a computer program from one place to
another. A storage media may be any available media that can be
accessed by a computer. By way of example, and not limitation, such
computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or
other optical disk storage, magnetic disk storage or other magnetic
storage devices, or any other medium that can be used to carry or
store desired program code in the form of instructions or data
structures and that can be accessed by a computer. Also, any
connection is properly termed a computer-readable medium. For
example, if the software is transmitted from a website, server, or
other remote source using a coaxial cable, fiber optic cable,
twisted pair, digital subscriber line (DSL), or wireless
technologies such as infrared, radio, and microwave, then the
coaxial cable, fiber optic cable, twisted pair, DSL, or wireless
technologies such as infrared, radio, and microwave are included in
the definition of medium. Disk and disc, as used herein, includes
compact disc (CD), laser disc, optical disc, digital versatile disc
(DVD), floppy disk and Blu-ray disc where disks usually reproduce
data magnetically, while discs reproduce data optically with
lasers. Thus, in some aspects computer readable medium may comprise
non-transitory computer readable medium (e.g., tangible media).
[0257] The methods disclosed herein comprise one or more steps or
actions for achieving the described method. The method steps and/or
actions may be interchanged with one another without departing from
the scope of the claims. In other words, unless a specific order of
steps or actions is specified, the order and/or use of specific
steps and/or actions may be modified without departing from the
scope of the claims.
[0258] Thus, certain aspects may comprise a computer program
product for performing the operations presented herein. For
example, such a computer program product may comprise a computer
readable medium having instructions stored (and/or encoded)
thereon, the instructions being executable by one or more
processors to perform the operations described herein. For certain
aspects, the computer program product may include packaging
material.
[0259] Software or instructions may also be transmitted over a
transmission medium.
[0260] For example, if the software is transmitted from a website,
server, or other remote source using a coaxial cable, fiber optic
cable, twisted pair, digital subscriber line (DSL), or wireless
technologies such as infrared, radio, and microwave, then the
coaxial cable, fiber optic cable, twisted pair, DSL, or wireless
technologies such as infrared, radio, and microwave are included in
the definition of transmission medium.
[0261] Further, it should be appreciated that components, modules,
and/or other appropriate means for performing the methods and
techniques described herein can be downloaded and/or otherwise
obtained by a user terminal and/or base station as applicable. For
example, such a device can be coupled to a server to facilitate the
transfer of means for performing the methods described herein.
Alternatively, various methods described herein can be provided via
storage means (e.g., RAM, ROM, a physical storage medium such as a
compact disc (CD) or floppy disk, etc.), such that a user terminal
and/or base station can obtain the various methods upon coupling or
providing the storage means to the device. Moreover, any other
suitable technique for providing the methods and techniques
described herein to a device can be utilized.
[0262] It is to be understood that the claims are not limited to
the precise configuration and components illustrated above. Various
modifications, changes and variations may be made in the
arrangement, operation and details of the methods and apparatus
described above without departing from the scope of the claims.
[0263] While the foregoing is directed to aspects of the present
disclosure, other and further aspects of the disclosure may be
devised without departing from the basic scope thereof, and the
scope thereof is determined by the claims that follow.
[0264] The previous description is provided to enable any person
skilled in the art to practice the various aspects described
herein. Various modifications to these aspects will be readily
apparent to those skilled in the art, and the generic principles
defined herein may be applied to other aspects. Thus, the claims
are not intended to be limited to the aspects shown herein, but is
to be accorded the full scope consistent with the language claims,
wherein reference to an element in the singular is not intended to
mean "one and only one" unless specifically so stated, but rather
"one or more." Unless specifically stated otherwise, the term
"some" refers to one or more. All structural and functional
equivalents to the elements of the various aspects described
throughout this disclosure that are known or later come to be known
to those of ordinary skill in the art are expressly incorporated
herein by reference and are intended to be encompassed by the
claims. Moreover, nothing disclosed herein is intended to be
dedicated to the public regardless of whether such disclosure is
explicitly recited in the claims. No claim element is to be
construed under the provisions of 35 U.S.C. .sctn. 112(f), unless
the element is expressly recited using the phrase "means for" or,
in the case of a method claim, the element is recited using the
phrase "step for."
* * * * *