U.S. patent application number 16/116781 was filed with the patent office on 2019-01-10 for methods and systems for receiver initiated protection of a wireless communication exchange.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Alfred Asterjadhi, Simone Merlin.
Application Number | 20190014597 16/116781 |
Document ID | / |
Family ID | 55443334 |
Filed Date | 2019-01-10 |
View All Diagrams
United States Patent
Application |
20190014597 |
Kind Code |
A1 |
Asterjadhi; Alfred ; et
al. |
January 10, 2019 |
METHODS AND SYSTEMS FOR RECEIVER INITIATED PROTECTION OF A WIRELESS
COMMUNICATION EXCHANGE
Abstract
Systems, methods, and devices for wireless communication are
disclosed. In some aspects, a method includes receiving from a
transmitting device, via a receiving device, a first wireless
frame, the first wireless frame forming at least a portion of a
wireless communication exchange between the transmitting device and
the receiving device, transmitting to the transmitting device, in
response to the first wireless frame, a second wireless frame
indicating that the receiving device will enable protection for a
remaining portion of the wireless communication exchange,
transmitting during a contention period, in response to the
indication, a frame reserving the wireless medium for a time
period; and receiving, via the receiving device, the remaining
portion of the wireless communication exchange from the
transmitting device during the time period.
Inventors: |
Asterjadhi; Alfred; (San
Diego, CA) ; Merlin; Simone; (San Diego, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
55443334 |
Appl. No.: |
16/116781 |
Filed: |
August 29, 2018 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
15018790 |
Feb 8, 2016 |
10111258 |
|
|
16116781 |
|
|
|
|
62116293 |
Feb 13, 2015 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 1/1678 20130101;
H04W 74/085 20130101; H04L 1/1887 20130101; H04W 28/26 20130101;
H04W 72/0446 20130101; H04L 1/1671 20130101; H04W 74/08 20130101;
H04L 47/826 20130101; H04W 74/006 20130101; H04L 1/1864 20130101;
H04L 5/0055 20130101 |
International
Class: |
H04W 74/08 20090101
H04W074/08; H04L 12/911 20130101 H04L012/911; H04L 1/16 20060101
H04L001/16; H04W 74/00 20090101 H04W074/00; H04W 72/04 20090101
H04W072/04; H04L 5/00 20060101 H04L005/00; H04L 1/18 20060101
H04L001/18 |
Claims
1. A method of wireless communication on a wireless medium,
comprising: receiving, by a receiving device, a first wireless
frame, from a transmitting device, during a contention period, the
first wireless frame forming a portion of a wireless communication
exchange between the transmitting device and the receiving device,
the first wireless frame including two or more transmission
parameters in a physical (PHY) header of the first wireless frame,
the two or more transmission parameters including at least an
identifier; determining, by the receiving device, whether the
receiving device is an intended recipient of the first wireless
frame based on the two or more transmission parameters included in
the PHY header of the first wireless frame; in response to the
receiving device determining that the first wireless frame is
intended for the receiving device, transmitting, by the receiving
device, during the contention period, and based on the two or more
transmission parameters included in the PHY header of the first
wireless frame, a second wireless frame indicating that a network
allocation vector for the wireless medium is set for a time period
of a duration sufficient to protect a remaining portion of the
wireless communication exchange between the transmitting device and
the receiving device from packet collisions; and receiving, via the
receiving device, the remaining portion of the wireless
communication exchange, from the transmitting device, during the
time period.
2. The method of claim 1, wherein the identifier identifies the
receiving device, and wherein the receiving device is an access
point.
3. The method of claim 1, wherein the identifier identifies the
transmitting device, and wherein the transmitting device is a
station.
4. The method of claim 1, wherein the two or more transmission
parameters includes an indicator of a transmission direction of the
first wireless frame.
5. The method of claim 1, wherein the two or more transmission
parameters includes an identifier of a BSS color.
6. The method of claim 1, wherein the two or more transmission
parameters includes at least one of a modulation and coding scheme
(MCS), a transmission bandwidth, a number of spatial streams (NSS),
an indication of a PPDU duration, and an indication of a use of
LDPC or BCC.
7. The method of claim 1, wherein the two or more transmission
parameters includes at least one of a subchannel index within the
bandwidth used for transmitting the payload, a SU/MU mode, and
channel information.
8. The method of claim 1, wherein the two or more transmission
parameters include a channel allocation for the transmission of the
remaining portion of the wireless communication exchange.
9. The method of claim 1, further comprising transmitting to the
transmitting device, in response to the first wireless frame, a
third wireless frame indicating that the receiving device will
protect the wireless medium for the remaining portion of the
wireless communication exchange.
10. The method of claim 1, further comprising decoding the first
wireless frame to determine the transmitting device requests that
the receiving device protect the wireless medium for the remaining
portion of the wireless communication exchange; and transmitting
the second wireless frame in response to the determination.
11. An apparatus for wireless communication on a wireless medium,
comprising: a receiver configured to receive a first wireless
frame, from a transmitting device, during a contention period, the
first wireless frame forming a portion of a wireless communication
exchange between the transmitting device and the apparatus, the
first wireless frame including two or more transmission parameters
in a physical (PHY) header of the first wireless frame, the two or
more transmission parameters including at least an identifier; a
processor configured to determine whether the apparatus is an
intended recipient of the first wireless frame based on the two or
more transmission parameters included in the PHY header of the
first wireless frame; and a transmitter configured to, in response
to the processor determining that the first wireless frame is
intended for the apparatus, transmit during the contention period,
and based on the two or more transmission parameters included in
the PHY header of the first wireless frame, a second wireless frame
indicating that a network allocation vector for the wireless medium
is set for a time period of a duration sufficient to protect a
remaining portion of the wireless communication exchange between
the transmitting device and the apparatus from packet collisions;
and completing the wireless communication exchange during the time
period.
12. The apparatus of claim 11, wherein the identifier identifies
the apparatus, and wherein the apparatus is an access point.
13. The apparatus of claim 11, wherein the identifier identifies
the transmitting device, and wherein the transmitting device is a
station.
14. The apparatus of claim 11, wherein the two or more transmission
parameters includes an indicator of a transmission direction of the
first wireless frame.
15. The apparatus of claim 11, wherein the two or more transmission
parameters includes an identifier of a BSS color.
16. The apparatus of claim 11, wherein the two or more transmission
parameters includes at least one of a modulation and coding scheme
(MCS), a transmission bandwidth, a number of spatial streams (NSS),
an indication of a PPDU duration, and an indication of a use of
LDPC or BCC.
17. The apparatus of claim 11, wherein the two or more transmission
parameters includes at least one of a subchannel index within the
bandwidth used for transmitting the payload, a SU/MU mode, and
channel information.
18. The apparatus of claim 11, wherein the two or more transmission
parameters include a channel allocation for the transmission of the
remaining portion of the wireless communication exchange.
19. The apparatus of claim 11, wherein the transmitter is further
configured to transmit to the transmitting device, in response to
the first wireless frame, a third wireless frame indicating that
the apparatus will protect the wireless medium for the remaining
portion of the wireless communication exchange.
20. The apparatus of claim 11, wherein the processor is further
configured to decode the first wireless frame to determine the
transmitting device requests that the apparatus protect the
wireless medium for the remaining portion of the wireless
communication exchange; and wherein the transmitter is further
configured to transmit the second wireless frame in response to the
determination.
21. A method of wireless communication on a wireless medium,
comprising: generating, by a transmitting device, a first wireless
frame to include two or more transmission parameters in a physical
(PHY) header of the first wireless frame, the two or more
transmission parameters including at least an identifier;
transmitting, by the transmitting device, the first wireless frame,
to a receiving device during a contention period, the first
wireless frame forming a portion of a wireless communication
exchange between the transmitting device and the receiving device;
receiving, by the transmitting device, during the contention
period, a second wireless frame indicating that a network
allocation vector for the wireless medium should be set for a time
period of a duration sufficient to protect a remaining portion of
the wireless communication exchange between the transmitting device
and the receiving device from packet collisions; and transmitting,
by the transmitting device, the remaining portion of the wireless
communication exchange, to the receiving device, during the time
period.
22. The method of claim 21, wherein the identifier identifies the
transmitting device, and wherein the transmitting device is a
station.
23. The method of claim 21, wherein the identifier identifies the
receiving device, and wherein the receiving device is an access
point.
24. The method of claim 21, wherein the two or more transmission
parameters includes an indicator of a transmission direction of the
first wireless frame.
25. The method of claim 21, wherein the two or more transmission
parameters includes an identifier of a BSS color.
26. The method of claim 21, wherein the two or more transmission
parameters includes at least one of a modulation and coding scheme
(MCS), a transmission bandwidth, a number of spatial streams (NSS),
an indication of a PPDU duration, and an indication of a use of
LDPC or BCC.
27. The method of claim 21, wherein the two or more transmission
parameters includes at least one of a subchannel index within the
bandwidth used for transmitting the payload, a SU/MU mode, and
channel information.
28. The method of claim 21, wherein the two or more transmission
parameters include a channel allocation for the transmission of the
remaining portion of the wireless communication exchange.
29. The method of claim 21, further comprising receiving from the
receiving device, in response to the first wireless frame, a third
wireless frame indicating that the receiving device will protect
the wireless medium for the remaining portion of the wireless
communication exchange.
30. The method of claim 21, wherein the first wireless frame
includes an indication of a request for the receiving device to set
the network allocation vector.
31. An apparatus for wireless communication on a wireless medium,
comprising: a processor configured to generate a first wireless
frame to include two or more transmission parameters in a physical
(PHY) header of the first wireless frame, the two or more
transmission parameters including at least an identifier; a
transmitter configured to transmit the first wireless frame, to a
receiving device during a contention period, the first wireless
frame forming a portion of a wireless communication exchange
between the apparatus and the receiving device; a receiver
configured to receive during the contention period, a second
wireless frame indicating that a network allocation vector for the
wireless medium should be set for a time period of a duration
sufficient to protect a remaining portion of the wireless
communication exchange between the apparatus and the receiving
device from packet collisions; and wherein the transmitter is
further configured to transmit the remaining portion of the
wireless communication exchange, to the receiving device, during
the time period.
32. The apparatus of claim 31, wherein the identifier identifies
the apparatus, and wherein the apparatus is a station.
33. The apparatus of claim 31, wherein the identifier identifies
the receiving device, and wherein the receiving device is an access
point.
34. The apparatus of claim 31, wherein the two or more transmission
parameters includes an indicator of a transmission direction of the
first wireless frame.
35. The apparatus of claim 31, wherein the two or more transmission
parameters includes an identifier of a BSS color.
36. The apparatus of claim 31, wherein the two or more transmission
parameters includes at least one of a modulation and coding scheme
(MCS), a transmission bandwidth, a number of spatial streams (NSS),
an indication of a PPDU duration, and an indication of a use of
LDPC or BCC.
37. The apparatus of claim 31, wherein the two or more transmission
parameters includes at least one of a subchannel index within the
bandwidth used for transmitting the payload, a SU/MU mode, and
channel information.
38. The apparatus of claim 31, wherein the two or more transmission
parameters include a channel allocation for the transmission of the
remaining portion of the wireless communication exchange.
39. The apparatus of claim 31, wherein the receiver is further
configured to receive, in response to the first wireless frame, a
third wireless frame indicating that the receiving device will
protect the wireless medium for the remaining portion of the
wireless communication exchange.
40. The apparatus of claim 31, wherein the processor is further
configured to generate the first wireless frame to include an
indication of a request for the receiving device to set the network
allocation vector.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/018,790, titled METHODS AND SYSTEMS FOR
RECEIVER INITIATED PROTECTION OF A WIRELESS COMMUNICATION EXCHANGE
and filed on Feb. 8, 2016, which claims the benefit of priority
under 35 U.S.C. .sctn. 119(e) to U.S. provisional patent
application No. 62/116,293, titled METHODS AND SYSTEMS FOR RECEIVER
INITIATED PROTECTION OF A WIRELESS COMMUNICATION EXCHANGE and filed
on Feb. 13, 2015, the entire disclosure of each of which is
incorporated by reference herein for all purposes and forms a part
of this specification. Any and all applications, for which a
foreign or domestic priority claim is identified in the Application
Data Sheet is filed with the present application, are hereby
incorporated by reference.
FIELD OF THE INVENTION
[0002] The present application relates generally to wireless
communications, and more specifically to systems, methods, and
devices for protecting a wireless medium from collisions or for
helping the transmitter to gain access to the medium during a
wireless communication exchange between a transmitter and a
receiver.
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,
SONET (Synchronous Optical Networking), 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.
[0005] A device on a wireless network may experience collisions,
especially in dense network environments. In some cases, the
frequency of collisions may prevent the device from communicating
effectively on the wireless network. In certain other case the
device may not be able to access the medium for long periods of
time due to continuous access of hidden nodes. Thus, there is a
need to improve the reliability of devices transmitting within
dense network environments.
SUMMARY OF THE INVENTION
[0006] The systems, methods, 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 communications between
first and second devices in a wireless network. In an embodiment,
the first and second devices may be access points and stations
(STAs) in the wireless network.
[0007] One aspect disclosed is a method of wireless communication
on a wireless medium, the method comprising receiving, by a
receiving device, a first wireless frame from a transmitting device
during a contention period, the first wireless frame forming a
portion of a wireless communication exchange between the
transmitting device and the receiving device, transmitting during
the contention period, a second wireless frame indicating a network
allocation vector for the wireless medium should be set for a time
period of a duration sufficient to protect a remaining portion of
the wireless communication exchange from packet collisions, and
receiving, via the receiving device, the remaining portion of the
wireless communication exchange from the transmitting device during
the time period.
[0008] In some aspects, the wireless communication exchange
includes one or more wireless frames with a more data indication,
and corresponding acknowledgments for the one or more wireless
frames. In some aspects, the method also includes determining that
the first wireless frame includes an error, wherein the
transmitting of the second wireless frame is in response to the
determining. In some aspects, the method includes transmitting to
the transmitting device, in response to the first wireless frame, a
third wireless frame indicating that the receiving device will
protect the wireless medium for the remaining portion of the
wireless communication exchange. In some aspects, the method
includes decoding the first wireless frame to determine the
transmitting device requests that the receiving device protect the
wireless medium for the remaining portion of the wireless
communication exchange; and transmitting the second wireless frame
in response to the determination. In some aspects, the method
includes generating the third wireless frame to indicate a time
when the receiving device will protect the wireless medium. In some
aspects, the method includes generating the third wireless frame to
indicate one or more transmission parameters for the transmitting
device. In some aspects, the one or more transmission parameters
include one or more of a modulation and coding scheme, use of
LDPC/BCC, a number of spatial streams, a transmission bandwidth, or
channel information, or a channel allocation for the transmission
of the remaining portion of the wireless communication exchange,
etc.
[0009] Another aspect disclosed is an apparatus for wireless
communication on a wireless medium. The apparatus includes a
receiver configured to receive a first wireless frame from a
transmitting device during a contention period, the first wireless
frame forming at least a portion of a wireless communication
exchange between the transmitting device and the apparatus; and a
transmitter configured to transmit during the contention period, a
second wireless frame indicating a network allocation vector for
the wireless medium is set for a time period of a duration
sufficient to protect a remaining portion of the wireless
communication exchange from packet collisions; and completing the
wireless communication exchange during the time period.
[0010] In some aspects of the apparatus, the wireless communication
exchange includes one or more wireless frames with a more data
indication, and corresponding acknowledgments for the one or more
wireless frames. In some aspects, the apparatus also includes a
processor configured to determine that the first wireless frame
includes an error, wherein the transmitter is further configured to
transmit the second wireless frame in response to the
determining.
[0011] In some aspects, the apparatus also includes transmitting to
the transmitting device, in response to the first wireless frame, a
third wireless frame indicating that the apparatus will transmit
the second wireless frame. In some aspects, the apparatus also
includes a processor configured to decode the first wireless frame
to determine the transmitting device requests that the apparatus
set the network allocation vector for the time period for the
duration sufficient to protect the remaining portion of the
wireless communication exchange from packet collisions. In some
aspects, the apparatus also includes a processor configured to
generate the third wireless frame to indicate one or more
transmission parameters for the transmitting device, wherein the
one or more transmission parameters include one or more of a
modulation and coding scheme, a transmission bandwidth, channel
information, and a channel allocation.
[0012] In some aspects, the apparatus includes a processor
configured to generate the third wireless frame as one of a block
acknowledgment or a negative acknowledgment. In some aspects, the
apparatus includes a processor configured to generate the third
wireless frame to indicate a time when the apparatus will transmit
the second wireless frame. In some aspects, the apparatus includes
a processor configured to generate the third wireless frame to
indicate one or more transmission parameters. In some aspects, the
apparatus includes a processor configured to generate the third
wireless frame to indicate a duration of time for which the network
allocation vector will be set. In some aspects, the apparatus
includes a processor configured to determine a time necessary to
complete the wireless communication exchange, and generate the
second wireless frame to protect the wireless medium for at least
the time necessary. In some aspects of the apparatus, the
transmitter is further configured to transmit the second wireless
frame protecting the wireless medium as a clear-to-send frame
intended for the transmitting device (of the first wireless frame),
the clear-to-send frame indicating a duration greater than or equal
to a time necessary to transmit the remaining portion. In another
aspect of the apparatus, the transmitter is further configured to
transmit the second wireless frame protecting the wireless medium
as a trigger frame, indicating a duration greater than or equal to
a time necessary to transmit the remaining portion, the transmit
parameters (e.g., MCS, BW, resource allocation [the channel
allocation to be used for delivering the wireless frame], etc.),
wherein the trigger frame enables for transmission, after a
predefined time (e.g., SIFS), one or more wireless devices in SU
mode or MU mode, wherein the first wireless device is part of the
one or more wireless devices.
[0013] Another aspect disclosed is a method of wireless
communication over a wireless medium. The method includes
transmitting, by a transmitting device, a first wireless frame to a
receiving device during a contention period, the first wireless
frame comprising a portion of a wireless communication exchange
between the transmitting device and the receiving device, receiving
a second wireless frame from the receiving device, the second
wireless frame indicating a network allocation vector should be set
for a time period, and completing, by the transmitting device, the
wireless communication exchange with the receiving device during
the time period.
[0014] In some aspects, the method also includes generating the
first wireless frame to comprise an indication of a request for the
receiving device to set the network allocation vector. In some
aspects, the method also includes receiving, from the receiving
device, a third wireless frame different than the second wireless
frame, the third wireless frame comprising an indication that the
receiving device will request the network allocation vector be set;
and in response to the third wireless frame, deferring further
transmissions of the wireless communication exchange until the
network allocation vector is set. In some aspects, the method also
includes decoding the third wireless frame to determine one or more
of a confirmation of transmission parameters included in the first
wireless frame, and one or more transmission parameters for
transmission to the receiving device.
[0015] In some aspects, the method also includes: generating the
first wireless frame as a data frame with a more data indication,
wherein completing transmission of the wireless communication
exchange comprises transmitting one or more additional data frames
and receiving corresponding acknowledgments for the one or more
additional data frames.
[0016] Another aspect disclosed is an apparatus for wireless
communication over a wireless medium. The apparatus includes a
transmitter configured to transmit a first wireless frame to a
receiving device during a contention period, the first wireless
frame comprising a portion of a wireless communication exchange
between the apparatus and the apparatus, a receiver configured to
receive a second wireless frame indicating a network allocation
vector should be set for a time period, and completing the wireless
communication exchange with the receiving device during the time
period. In some aspects, the apparatus also includes a processor
configured to generate the first wireless frame to comprise an
indication of a request for the receiving device to set the network
allocation vector. In some aspects, the apparatus also includes a
processor, wherein the receiver is further configured to receive a
third wireless frame comprising an indication that the receiving
device will set the network allocation vector, and the processor is
configured to, in response to the third wireless frame, defer
further transmissions of the wireless communication exchange until
the network allocation vector is set. In some aspects, the
processor is further configured to decode the third wireless frame
to determine one or more of a confirmation of transmission
parameters included in the first wireless frame, and one or more
transmission parameters for transmission to the receiving device.
In some aspects, the apparatus also includes a processor configured
to generate the first wireless frame as a data frame with a more
data indication, wherein completing transmission of the wireless
communication exchange comprises transmitting one or more
additional data frames and receiving corresponding acknowledgments
for the transmitted data frames.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 shows an exemplary wireless communication system
100.
[0018] FIG. 2 shows an exemplary functional block diagram of a
wireless device 202 that may be employed within the wireless
communication system of FIG. 1.
[0019] FIG. 3 is a timing diagram of one embodiment of a wireless
communication exchange between an access point and a station
(STA).
[0020] FIG. 4A is another timing diagram of one embodiment of a
wireless communication exchange between an access point and a
station.
[0021] FIG. 4B is another timing diagram of one embodiment of a
wireless communication exchange between an access point and a
station.
[0022] FIG. 5A shows an example of a media access control
frame.
[0023] FIG. 5B shows an example of a trigger frame.
[0024] FIG. 5C shows an example of a response frame.
[0025] FIG. 6 is a flowchart of a method of wireless
communication.
[0026] FIG. 7 is a flowchart of a method of wireless
communication.
[0027] FIG. 8A shows an organization of a wireless frame.
[0028] FIG. 8B shows another organization of a wireless frame.
[0029] FIG. 9 is a flowchart of a method of determining whether a
frame that includes errors is addressed to a device receiving the
frame.
DETAILED DESCRIPTION
[0030] Various aspects of the novel systems, apparatuses, 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, 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.
[0031] 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.
[0032] 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.
[0033] In some aspects, wireless signals in a sub-gigahertz band
may be transmitted according to the 802.11 protocol using
orthogonal frequency-division multiplexing (OFDM), frequency
division multiplexing (FDM), time division multiplexing (TDM),
direct-sequence spread spectrum (DSSS) communications, a
combination of OFDM and DSSS communications, multi user (MU,
multi-input multi output (MIMO)), or other schemes which can be
used for single user (SU) or multi user (MU) communications,.
Implementations of the 802.11 protocol may be used for high
efficiency, very high throughput, real time communications,
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. Devices may
also realize more efficient wireless communication due to reduced
probability of collisions when utilizing the disclosed methods and
systems.
[0034] 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., Institute
of Electronical and Electronic Engineers (IEEE) 802.11 protocol
such as 802.11) 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.
[0035] An access point ("AP") 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, or some other terminology.
[0036] A station "STA" 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, 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.
[0037] As discussed above, wireless devices operating within dense
networks may at times experience packet collisions caused by
transmissions of other devices operating on the same wireless
medium and at times may not even be able to access the medium due
to continuous usage of the medium by other devices. These
collisions may degrade the communications efficiency of the
wireless device and the wireless network as a whole. In some
scenarios, a receiving device may experience a higher frequency of
collisions than a transmitting device during a communications
exchange between the two devices. In these scenarios, while the
transmitting device may be able to contend for the wireless medium
with an acceptable efficiency, the receiver's efficiency may be
below an acceptable level. For example, a station in communication
with an access point may transmit a frame when its random back-off
expires. If the station is operating on a wireless medium with high
utilization, there may be a high likelihood that this transmission
will fail due to collisions with hidden nodes. Similarly such
failures may be caused due to interference, channel conditions or
wrong selection of transmit parameters by the transmitting
device.
[0038] Upon detection of the failed transmission, the station may
retransmit the frame after restarting its back-off timer. The
restarted back-off timer may utilize a new random value that is
larger than the previous random value, in some cases selected from
a range of values that is double the previous range of values.
Thus, time to gain access to the medium by the station is
substantially increased in the presence of collisions. In some
aspects, the station may retransmit the message at a lower data
rate to increase the likelihood that the retransmission does not
fail. This further compromises the media effective capacity for the
station. In some instances, the station may experience continuous
collisions, such that the station is essentially "starving" for
medium access. The disclosed methods and systems resolve these
issues, resulting in increased throughput, reduced latency, and
increased network efficiency.
[0039] In particular, in the instances described above, it may be
desirable for the receiving device to enable the access to the
medium for the transmitting device and/or to protect the
communication exchange with the transmitting device and reduce a
frequency of collisions experienced by the receiving device during
the exchange. Similarly, in some scenarios the transmitter may not
be able to gain access to the medium such that it may transmit a
frame to an intended receiver due to continuous usage of the medium
by other devices. In these scenarios, it may be desirable for the
receiver to enable access to the medium for the transmitting device
as described herein.
[0040] The disclosed methods and systems provide for requesting and
receiving protection of a medium during a wireless communication
exchange. In some aspects, a device transmitting data requests that
a device to which the transmitted data is addressed initiate the
protection of the medium. This may differ from traditional methods
that typically may have a device that intends to transmit data (for
example, transmit a data message to a receiving device) also
initiate protection for the data (for example, by transmitting a
request to send message). Receiver initiated protection, as
described above, may be particularly beneficial when a medium
environment in proximity to a transmitter of the data is
substantially different from the medium environment in proximity to
the receiver of the data. For example, in some aspects, the
receiver of the data may be experiencing a relatively high level of
packet collisions, whereas the transmitter of the data may be
experiencing a rather lower level of packet collisions. Therefore,
in some aspects, it may be more effective for the receiver of the
data to initiate the protection instead of the transmitter. For
example, in some aspects, the transmitter may be effectively hidden
from other devices with which its transmissions may be colliding.
In other words, it may be desirable to initiate protection for a
communication exchange at a device closest in proximity to
potential collision inducing devices, or by a device with the
highest likelihood of reaching potential collision inducing
devices, such that those devices are more likely to receive frames
indicating the protection (such as a request to send and/or clear
to send) and set their network allocation vector appropriately.
Thus, the disclosed methods and systems recognize that, unlike
traditional methods, it is not always most effective for a
transmitter of data to initiate protection for the data, but may
be, in some situations, more effective for a transmitter to ask the
receiver of the data to initiate the protection, and thus reach
potential collision inducing nodes within a transmit range of the
receiver.
[0041] There are several different types of wireless communication
exchanges that may be protected by the methods and systems
described herein. For example, one wireless communication exchange
that may be protected is a sequence of data frames, with most of
the data frames including a "more data" indication (except perhaps
the last data frame that is part of the exchange). In this example,
the transmitter of the data frames may request the receiver of the
data frames to initiate the protection for the sequence of data
frames or at least a portion of the sequence of data frames. The
exchange may also include acknowledgements or block acknowledgments
corresponding to each of the data frames.
[0042] More generally, a wireless communication exchange may take
the form, in some embodiments, of: FRAME 1 | SIFS | (Optional
[ACK1, NACK1, BlockAck1]) . . . [PREDEFINED TIME], FRAME 2 | SIFS2
| FRAME 3 | [ACK2, NACK2, BA2]. The underlined portion may have
multiple occurrences in some aspects. In the above generalized
description, the PREDEFINED TIME is short interframe space (SIFS),
or PCF Interframe Space (PIFS), or after Enhanced Distributed
Channel Access (EDCA) contention. (also the above SIFS can be the
predefined time).
[0043] FRAME 1 may be transmitted by/from a transmitter to a
receiver: In some aspects, FRAME 1 may include an indication of a
request for protection of the communication exchange. FRAME 1 may
include a request for protection in several different ways
depending on the embodiment. For example, if FRAME 1 contains one
or more errors in portions of it when it is received (e.g., one or
more MPDUs contained in it may be corrupted (i.e., one or more FCS
fails), then this may be interpreted as a request for protection in
some aspects. Alternatively, FRAME 1 may include an explicit
indication of a request for protection. For example, in some
aspects, a particular field in FRAME 1, if set to a predefined
value, may be a request for protection. Some implementations may
utilize a Retry bit of FRAME 1 for this indication. In some
aspects, if Frame 1 contains an indication of additional data to be
delivered to the recipient (More Data bit, Queue Size in the QoS
Control field, Buffer Size in the HT Control field), this may
indicate a request for protection of the wireless communication
exchange. In some aspects, an explicit frame type is defined to
request protection. For example, an RTS frame may fit into this
category. In the above description, the ACK1, NACK1, BA1 are sent
from the receiving device (the device acknowledging the data) to
the transmitting device (the device transmitting the data).
[0044] In the above example of a wireless communication exchange,
Frame 2 is transmitted from the receiver to transmitter (and can be
addressed to multiple transmitters if, for example, it is a trigger
frame). Frame 2 may be a clear-to-send frame that is transmitted
with a receiver address field set to the transmitter address field
(a so called "CTS-To Self"), a Trigger frame (which can be
addressed to one or more transmitters (one of which is "our"
transmitter, an MU PPDU that contains one or more (A-)MPDUs, which
can contain the Trigger frame as one or more of the MPDUs, or may
contain the trigger information in the MAC header of the MPDUs,
etc. In some aspects, Frame 2 may function to replace the ACK1,
NACK, BA1 in the sequence. FRAME 3 may be sent from the transmitter
to the receiver (and may be sent in a multi user PPDU, in some
aspects along with frames from other transmitters, if the FRAME 1
includes subchannel allocations, and other TX parameters, for
sending the frames).
[0045] In some aspects, FRAME 3 includes one or more MPDUs which
are derived from the information indicated or obtained from Frame 1
(e.g., one or more MPDUs could be the ones that failed one
transmitted in Frame 1, or whose presence was indicated in Frame 1
etc. ACK2, NACK2, or BA2 may be transmitted from the receiver to
the transmitter.
[0046] Enabling access to the medium may include transmitting a
message from the receiver to the transmitter that allows the
transmitter to discard or otherwise ignore previously set network
allocation vector (NAV) durations or deferral mechanisms and access
the medium to initiate the communications exchange within a
predefined time after reception of the frame that is transmitted by
the receiver. The pre-defined time may be short interframe space
(SIFS), point coordination function (PCF) Interframe Space (PIFS)
or some known duration of time. Protection of the communication
exchange may include transmitting one or more messages that cause
devices on the medium (and receiving the messages) to set their NAV
for a duration of time. The network allocation vector (NAV) may be
a virtual carrier-sensing mechanism used to limit the need for
physical carrier-sensing at a wireless air interface in order to
save power. For example, in some aspects, a MAC layer frame header
may contain a duration field that specifies the transmission time
required for a frame or series of frames, in which time the medium
will be busy. In another example, a PHY layer frame header may
contain a duration field, wherein the duration field may be located
in the L-SIG or in the SIG-A portion of the PHY header. Stations
listening on the wireless medium read the duration field and set
their network allocation vector, which is an indicator for a
station on how long it must defer from accessing the medium.
[0047] In some aspects, the network allocation vector may be
implemented as a counter, which counts down to zero at a uniform
rate. When the counter is zero, the virtual carrier sense mechanism
provided by the NAV indicates that the medium is idle. When the NAV
is non-zero, this indicates that the medium is busy.
[0048] Messages that set network allocation vectors may include,
for example, clear-to-send messages and/or trigger messages
(wherein in this context a trigger message enables the one or more
intended receivers of the trigger to transmit their data within a
predetermined period of time following the trigger, wherein the
data is transmitted in single user or in multi user mode (i.e., in
specified time/space/frequencies provided by the trigger frame
itself), or Null Data Packets (e.g., a frame that consists only of
the PHY header contents). Transmission of these messages may
inhibit transmissions of those devices (that are not the intended
receiver(s) of the messages) for the duration, thus reducing the
number of packet collisions experienced by the receiving device
during the duration of time. Since the receiving device transmits
the messages in some of the disclosed aspects, a first set of
wireless devices may receive the messages as compared to a second
set of devices that may receive similar messages transmitted by the
transmitting device. This may be advantageous in some scenarios.
For example, if a device that is somewhat distant from a
transmitting device is included in the first set of devices but not
in the second set of devices, transmissions by the transmitter
distant device may not be inhibited if the transmitting device
transmits the NAV setting messages (because the transmitter
distance device may not receive the messages--due to its distance
from the transmitter). Note that within the following description,
one that is skilled in the art may realize that reference to a
single transmitter may include any number of transmitters. For
example, when a particular disclosed message is sent by a device,
the device may enable a multitude of transmitters to transmit
following the message as described herein.
[0049] Additionally, in some aspects, an intended receiver device
of transmissions may be in a better position to determine whether
transmissions are being successfully received by it than the
transmitting device. Thus, the receiving device may condition
application of the disclosed techniques, which may cause a NAV to
be set, on whether packets transmitted/received during a contention
period are successfully received by the device. Thus, the receiving
device may be able to apply knowledge that the transmitting device
is unable to apply. Thus, setting the NAV to protect a
communication exchange may be performed only when necessary, thus
improving the ability of devices on the medium to coexist and
increasing medium utilization generally.
[0050] Thus, when the receiving device transmits the disclosed NAV
setting messages, there may be an increased probability that the
receiver will experience improved efficiency as compared to methods
that provide for the transmitting device to set the NAV.
[0051] FIG. 1 shows an exemplary wireless communication system 100.
The wireless communication system 100 may operate pursuant to a
wireless standard, for example the 802.11 standards. The wireless
communication system 100 may include an AP 104, which communicates
with STAs 106.
[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 106. For example, signals may be sent and
received between the AP 104 and the STAs 106 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 106 in accordance with Code Division Multiple
Access (CDMA) techniques. If this is the case, the wireless
communication system 100 may be referred to as a CDMA system. Maybe
good to specify MU, SU and MIMO here as well, and FDM and FDMA,
both multicarrier and single carrier.
[0053] A communication link that facilitates transmission from the
AP 104 to one or more of the STAs 106 may be referred to as a
downlink (DL) 108, and a communication link that facilitates
transmission from one or more of the STAs 106 to the AP 104 may be
referred to as an uplink (UL) 110. When the link is between one STA
and a peer STA it is referred to as single user (SU) while a link
between one STA and one or more STAs is referred to multi user
(MU). 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.
[0054] The AP 104 may act as a base station and provide wireless
communication coverage in a basic service area (BSA) 102. The AP
104 along with the STAs 106 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 104, but rather may function
as a peer-to-peer network between the STAs 106. Accordingly, the
functions of the AP 104 described herein may alternatively be
performed by one or more of the STAs 106.
[0055] The AP 104 may transmit a beacon signal (or simply a
"beacon"), via a communication link such as the downlink 108, to
other nodes STAs 106 of the system 100, which may help the other
nodes STAs 106 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 or as a
beacon interval. 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 or beacon interval 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
both common (e.g., shared) amongst several devices, and information
specific to a given device.
[0056] In some aspects, a STA 106 may be required to associate with
the AP 104 in order to send communications to and/or 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 106 may, for example, perform a
broad coverage search over a coverage region. A search may also be
performed by the STA 106 by sweeping a coverage region in a
lighthouse fashion, for example. After receiving the information
for associating, the STA 106 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).
[0057] FIG. 2 shows an exemplary 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 one of the STAs 106. The wireless device
202 may comprise a first wireless device or a second wireless
device.
[0058] 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 to implement the methods
described herein.
[0059] 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.
[0060] 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.
[0061] 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 location. The transmitter 210 and 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.
[0062] The wireless device 202 may also include a signal detector
218 that may be used in an effort to detect and quantify the level
of signals received by the transceiver 214. 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 protocol data unit (PPDU).
[0063] 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.
[0064] 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.
Those of skill in the art will appreciate the components of the
wireless device 202 may be coupled together or accept or provide
inputs to each other using some other mechanism.
[0065] Although a number of separate components are illustrated in
FIG. 2, those of skill in the art will recognize that 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 and/or the DSP 220. Further,
each of the components illustrated in FIG. 2 may be implemented
using a plurality of separate elements.
[0066] The wireless device 202 may comprise an AP 104, or a STA
106, and may be used to transmit and/or receive communications.
That is, either AP 104, or STA 106, may serve as transmitter or
receiver devices. Certain aspects contemplate signal detector 218
being used by software running on memory 206 and processor 204 to
detect the presence of a transmitter or receiver.
[0067] FIG. 3 is a timing diagram of one embodiment of a wireless
communication exchange 300 between an access point 104 and a
station 106a. FIG. 3 depicts the AP 104 within a dense networking
environment. For example, AP 104 may be within proximity of one or
more other wireless devices, for example, at least station 106b as
shown. The timing diagram begins at the left with the STA 106a
transmitting frame 1 302 to the AP 104. Because AP 104 is within a
dense network environment, the transmission of frame 1 may at least
partially overlap with the transmission of another frame from
another wireless device. As shown, STA 106b transmits "Frame 2" 304
partially simultaneously with "Frame 1" 302. This partial
simultaneous transmission may cause corruption of "Frame 1" 302
when received by AP 104.
[0068] While Frame 1 may be at least partially corrupted when
received by the AP 104, the AP 104 may still be able to determine
some information from the corrupted frame. For example, in some
cases, the device transmitting the frame may be determined via a
transmitter address field included in the frame. Other relevant
information may also be obtained from the corrupted frame. For
example, information such as any one or a modulation and coding
scheme (MCS), transmission bandwidth information, duration
information from the frame, and the intended receiver may be
determined. In some cases, this information may be contained in one
or more portions of a PHY header of the frame. For example, in some
aspects, a cyclic redundancy check (CRC) for the PHY header may
indicate the PHY header was received correctly. In response to this
indication, some aspects may decode on one or more fields from the
PHY header and rely on those values for further processing. In some
aspects, information may also be decoded from a media access
control (MAC) header of the received frame. Information in the MAC
header may or may not be protected by a CRC or similar error
correction mechanisms. Some aspects may utilize process 900,
discussed below with respect to FIG. 9, to obtain certain
information from a partially corrupted frame.
[0069] Because the "Frame 1" 302 is corrupted upon reception by AP
104, in the example message exchange of FIG. 3, AP 104 transmits a
negative acknowledgment frame 306 to STA 106a. In some aspects, a
negative acknowledgment may be indicated via an acknowledgment
frame that has any field in a frame control field set to a non-zero
value. For example, in some aspects, an acknowledgment packet with
a retry field set to a value of one may indicate a negative
acknowledgment. The negative acknowledgment frame 306 may also
indicate that the AP 104 will protect further portions of the
wireless communication exchange 300 by setting the network
allocation vector for a period of time sufficient or time necessary
to allow the exchange to complete. This indication may be provided
by setting one or more fields in the negative acknowledgment frame
306 to particular value(s). For example, a duration field of the
negative acknowledgment frame 306 may indicate a necessary time for
completing the wireless communication exchange.
[0070] The negative acknowledgment frame 306 may also include
indications of one or more suggested transmission parameters for
the transmitting device (in this case, the STA 106a) to use when
retransmitting "frame 1" 302. For example, the negative
acknowledgment frame 306 may include an indication of a new
modulation and coding scheme (MCS), transmission bandwidth, or
alternative channel information, such as channel allocation
information or a suggestion to use a particular secondary channel).
In some aspects, the negative acknowledgment frame may also
indicate an amount of time it will allocate for protection of the
remaining portion of the wireless communication exchange 300.
[0071] Upon receiving the negative acknowledgment frame including
the indications discussed above, the STA 106a may defer additional
transmissions on the wireless medium for a period of time. In some
aspects, the negative acknowledgment frame 306 may indicate a time
when the AP 104 will initiate protection by setting the network
allocation vector (NAV). In these aspects, the STA 106a may defer
additional transmissions until at least the indicated time. In some
aspects, the period of deferral may be fixed, or
pre-negotiated.
[0072] While FIG. 3 shows the transmission of the negative
acknowledgment frame 306, in some aspects, negative acknowledgment
frame 306 may not be transmitted. In these aspects, both STA 106a
and AP 104 may begin contending for the medium after frame 1 302 is
transmitted. The AP 104 may contend for the medium to send the
message that would allow STA 106a to gain access to the medium for
retransmitting "frame 1" 302, such as clear-to-send frame 308
discussed below. The STA 106a may contend for the medium in order
to retransmit "frame 1" after the STA 106a determines the
transmission was unsuccessful. Alternatively the STA 106a may
contend for the medium in order to transmit a request to send (RTS)
frame to the AP 104).
[0073] The AP 104 then starts contending for the wireless medium
and then transmits a clear-to-send (CTS) frame 308 when it wins
contention. In some aspects, the clear-to-send frame 308 may be
addressed to the STA 106a. For example, an A1 field of the CTS
frame 308 may identify the STA 106a (for example, by station
address). The CTS frame 308 may set the network allocation vector
315 for a period of time, for example, via a duration field in the
CTS frame 308. By setting the network allocation vector via the CTS
frame, the receiver device (in this case, the AP 104) may enable
the STA 106a to retransmit Frame 1 under the protection from
collisions provided by the NAV for the allocated duration of time
indicated in the CTS frame.
[0074] In some aspects, the CTS frame 308 may instead be any frame
that would enable a reverse direction transmission (such as a
reverse direction protocol). In some aspects the frame may be a
trigger frame (not shown in FIG. 3. The trigger frame may allocate
resources for one or more uplink stations (of which one is the STA
106a), such that these STAs may transmit their UL data as a
response to the Trigger frame, after a predefined time (e.g., after
SIFS) in the corresponding resources and using the transmit
parameters that are specified in the Trigger frame itself. The
trigger frame may include a transmission schedule specified by the
AP 104. In some aspects, the transmission schedule included in the
trigger frame may provide a schedule for one or more multi-user
frames to be transmitted as an uplink transmission. In some
aspects, the trigger frame may be followed by one or more downlink
frames that may be destined for devices other than but also
including the STA 106a.
[0075] Upon determining that the AP 104 has provided protection for
the wireless communication exchange 300, as indicated in the
negative acknowledgment frame 306 in certain embodiments, the STA
106a then retransmits "Frame 1" as packet 310. The acknowledgment
312 completes wireless communication exchange 300. Note that the AP
104 may transmit additional frames to the 106a (which may include
"Frame 1").
[0076] While FIG. 3 shows the AP 104 transmitting and receiving
particular messages, in some aspects, the devices shown in FIG. 3
may be reversed. For example, messages transmitted by the AP 104 in
FIG. 3 may instead be transmitted by the STA 106a. Similarly,
messages transmitted by the STA 106a in FIG. 3 may instead be
transmitted by the AP 104.
[0077] FIG. 4A is another timing diagram of one embodiment of a
wireless communication exchange 400 between an access point 104 and
a station 106a. FIG. 4A depicts the AP 104 within a dense
networking environment. For example, AP 104 may be within proximity
of one or more other wireless devices, for example, at least
station 106b as shown.
[0078] The wireless communication exchange 400 begins with the STA
106a transmitting a frame 402. In some aspects, the frame 402 may
include a more data indication and/or may carry more than one data
packet. In some aspects, one or more portions of the frame 402 may
be corrupted. While frame 402 may be at least partially corrupted
when received by the AP 104, the AP 104 may still be able to
determine some information from the corrupted frame. For example,
in some cases, the device transmitting the frame may be determined
via a transmitter address field included in the frame. Other
relevant information may also be obtained from the corrupted frame.
For example, information such as one or more of a modulation and
coding scheme (MCS), transmission bandwidth information, duration
information from the frame 402, and the intended receiver may be
determined. In some cases, this information may be contained in one
or more portions of a PHY header of the frame 402, such as in the
L-SIG, or SIG-A or SIG-B of the PHY header. For example, in some
aspects, a CRC (or a parity bit) for the PHY header may indicate
that the corresponding portion of the PHY header it protects was
received correctly. In response to this indication, some aspects
may decode on one or more portions/fields from the PHY header and
rely on those values for further processing. In some aspects,
information may also be decoded from a media access control (MAC)
header of the received frame 402. Information in the MAC header may
or may not be protected by a CRC or similar error correction
mechanisms. Some aspects may utilize process 900, discussed below
with respect to FIG. 9, to obtain certain information from the
partially corrupted frame 402.
[0079] The AP 104 then transmits a block acknowledgment message
404, at least partially acknowledging one or more of the data
frames that are contained in the frame 402. When one or more of the
data frames included in frame 402 are corrupted, the block
acknowledgment message 404 indicates that those particular frames
were not received successfully. The block acknowledgment message
404 may also include a first indication that the STA 106a will
protect a remaining portion of the wireless communication exchange
400. The block acknowledgment message 404 may also include a second
indication of an estimated time when the STA 106a will initiate the
protection. For example, the indication of the estimated time may
be a relative time offset from the transmission of the block
acknowledgment message 404.
[0080] The block acknowledgment message 404 may also include
indications of one or more suggested transmission parameters for
the transmitting device (in this case, the STA 106a) to use when
retransmitting frame 402. For example, the block acknowledgment
message 404 may include an indication of a new modulation and
coding scheme (MCS), transmission bandwidth, or alternative channel
information, such as channel allocation information or a suggestion
to use a particular secondary channel. In some aspects, the block
acknowledgment message 404 may also indicate an amount of time the
AP 104 will allocate for protection of the remaining portion of the
wireless communication exchange 400.
[0081] Upon receiving the block acknowledgment message 404 that
indicates the first indication, the STA 106a may defer
transmissions of the wireless communication exchange until at least
the time indicated by the second indication. Alternatively, the STA
106a may defer for a predetermined or negotiated period of time in
response to receiving the first indication.
[0082] The AP 104 then transmits the trigger frame 406. In some
aspects, the trigger frame 406 may include a transmission schedule
for one or more frames to be transmitted by the STA 106a. In some
aspects, the transmission schedule may also schedule one or more
frames to be transmitted by another device other than the STA 106a.
The trigger frame sets the network allocation vector 408 of devices
receiving the trigger frame 406 for a period of time T. In some
aspects, the trigger frame 406 may be a clear-to-send (CTS) frame.
For example, in some cases, the AP 104 may determine that it will
only schedule a data exchange with the STA 106a, for example, when
no other data transmissions are pending with other devices
associated with the AP 104. In this case, the AP 104 may determine
to use a CTS frame to reserve the NAV instead of the trigger frame
shown in FIG. 4A.
[0083] Upon determining that the AP 104 has protected a remaining
portion of the wireless communication exchange 400, the STA 106a
transmits frame 410 and frame 412. In some aspects, frame 410 may
include a more data indication while frame 412 does not. AP 104
then acknowledges frame 410 and frame 412 via block acknowledgment
414, completing the wireless communication exchange 400.
[0084] While FIG. 4A shows the AP 104 transmitting and receiving
particular messages, in some aspects, the devices shown in FIG. 4A
may be reversed. For example, messages transmitted by the AP 104 in
FIG. 4A may instead be transmitted by the STA 106a. Similarly,
messages transmitted by the STA 106a in FIG. 4A may instead be
transmitted by the AP 104.
[0085] FIG. 4B is another timing diagram of one embodiment of a
wireless communication exchange between an access point 104 and a
station 106a. Timing diagram 450 depicts the station 106a within a
dense networking environment. For example, station 106a may be
within proximity of one or more other wireless devices.
[0086] The timing diagram begins with the STA 106a transmitting a
frame 452. The frame 452 may be transmitted during a contention
period, when other devices may contend for access to the wireless
medium along with the STA 106a. A collision between the frame 452
and another frame (not shown) may occur, such that frame 452 is at
least partially corrupted when received by the AP 104. However, the
AP 104 may still be able to determine that the frame 452 originated
from the STA 106a. For example, this determination may be made in
some aspects using process 700 discussed in more detail below.
[0087] In response to reception of frame 452, which may be
partially corrupted, by the AP 104, the AP 104 may determine that
protection from collisions may be provided for a remaining portion
of a wireless communication exchange with the STA 106a. As
discussed above with respect to FIG. 4A, despite the frame 452
being corrupted, some information may still be obtained by the
receiving device AP 104. For example, in some cases, the device
transmitting the frame may be determined via a transmitter address
field included in the frame. Other relevant information may also be
obtained from the corrupted frame 452. For example, information
such as one or more of a modulation and coding scheme (MCS),
transmission bandwidth information, duration information from the
frame 452, and the intended receiver may be determined. In some
cases, this information may be contained in one or more portions of
a PHY header of the frame 452. For example, in some aspects, a CRC
for the PHY header may indicate the PHY header was received
correctly. In response to this indication, some aspects of the AP
104 may decode on one or more fields from the PHY header and rely
on those values for further processing. In some aspects,
information may also be decoded from a media access control (MAC)
header of the received frame 452. Information in the MAC header may
or may not be protected by a CRC or similar error correction
mechanisms. Some aspects may utilize process 900, discussed below
with respect to FIG. 9, to obtain certain information from the
partially corrupted frame 452.
[0088] As shown in FIG. 4B, the AP 104 may respond by transmitting
a trigger frame 454. In some aspects, the trigger frame may define
a transmission schedule. In some aspects, the transmission schedule
may schedule transmissions from the STA 106a as part of a
multi-user transmission which is performed at a time after the
trigger frame. The trigger frame may be transmitted by the AP 104
during a contention period. The trigger frame causes the NAV 456 to
be set as shown, such that data can be received from the STA 106a
with a reduced risk of corruption from collisions. For example, the
trigger frame 454 may include a duration field indicating the
length of the NAV 456. Note that while not shown in the figure one
or more STAs may be allocated to transmit during the scheduled
transmission time using multi-user transmissions such as MU-MIMO or
OFDMA.
[0089] At a time indicated by the trigger frame 454, the STA 106a
transmits three data packets 460a-c, which are all included in a
single aggregated media protocol data unit (A-MPDU) 462. The AP 104
may acknowledge one or more of the data packets 460a-c with block
acknowledgment packet 470, which is also transmitted under the
protection provided by the trigger frame 454.
[0090] While FIG. 4B shows the AP 104 transmitting and receiving
particular messages, in some aspects, the devices shown in FIG. 4B
may be reversed. For example, messages transmitted by the AP 104 in
FIG. 4B may instead be transmitted by the STA 106a. Similarly,
messages transmitted by the STA 106a in FIG. 4B may instead be
transmitted by the AP 104.
[0091] FIG. 5A shows an example wireless frame. The frame 500
includes one or more of the following a legacy preamble 502,
physical layer (PLCP) header 504 (which may contain one or more of
an STF, LTF, SIG-A, SIG-B etc.), and one or more media access
control (MAC) protocol data units (MPDU) 506, wherein the one or
more MPDUs may be carried as part of an aggregated MPDU (A-MPDU),
which is a structure that precedes each MPDU by an MPDU delimiter,
specifying the length of the MPDU and other information relevant
for processing the MPDU, and a certain amount of bytes (generally 0
to 3) follow each MPDU for padding purposes so that the overall
length of the A-MPDU subframe is a multiple of 4 octets. As an
example, each MPDU 506 includes one or more of the following
fields: a frame control field 507, duration id field 508, a first
address field 509, second address field 510, a Quality of Service
(QOS) control field 511, HT Control field and frame check sequence
field 512, along with other fields. The frame control field 507
includes a protocol version field 512a, type field 512b, subtype
field 512c, ToDS field 512d, FromDS field 512e, more fragment field
512f, Retry field 512g, Pwr Mgt field 512h, More Data field 512i,
Protected Frame (WEP) field 512j, and Order field 512k (this would
be the general structure when protocol version (PV) is zero (0)).
Other structures are also contemplated (e.g., PV=1 frames have a
different organization).
[0092] In some aspects, implementations may set the more fragment
field 512f to request that a receiver of the frame 500 initiate
protection for a data communications exchange including the frame
500. For example, in some aspects, a message conforming with frame
500 described with respect to FIG. 5 may be transmitted, but
includes only a portion of data for a destination device of the
frame 500. Thus, in some aspects, the message may be sent with the
more data field 512i set to a value of one (1). However, to ensure
reliable communication of a remaining portion of data transmitted
in subsequent frames, the transmitting device of the message may
request the receiving device (i.e. a device identified by a
receiver address of the frame 500), to initiate protection by
setting the more fragment field 512f. In some embodiments, the
Retry field or any other field present in frame 500 can be used for
this purpose.
[0093] The transmission parameters of the frame 500 are located in
the PHY header of the PPDU carrying one or more of the MPDUs, one
of which can be frame 500. The PHY header of the PPDU may contain
one or more of the following parameters (though not limited to) a
modulation and coding scheme (MCS), bandwidth, number of spatial
streams (NSS), PPDU duration, network allocation vector (NAV)
duration, transmitter identifier, receiver identifier, direction of
the frame (e.g., UL or DL), use of LDPC or BCC, subchannel index
within the bandwidth used for transmitting the payload (i.e., the
(A-)MPDU), SU/MU mode, BSS color (identifier), etc.
[0094] FIG. 5B shows an exemplary trigger frame 525. In some
aspects, the trigger frame 525 may be a clear to send frame. The
trigger frame 525 includes a frame control field 507, duration
field 515, a receiver address field 516, a transmitter address
field 517, a common info field 518, and a transmission schedule
530.
[0095] The transmission schedule field 530 defines when
transmissions may occur from one or more devices, identified by the
device id fields 532a-n during the protection initiated by a device
transmitting the trigger frame 525. Also included in the exemplary
trigger frame 525 are channel information fields 534a-n and
optionally start time fields 536a-n. The channel information fields
534a-n may indicate one or more of a channel allocation
information, modulation and coding scheme, spatial channel
identifiers, and/or frequency identifiers for use during a
multi-user transmission with other devices identified by the device
identifier fields 532a-n. The start time fields 536a-n may provide
a time reference indicating a time when transmissions to the device
sending the frame 525 should be initiated. In some aspects, the
start time may be relative to the time of transmission of the
trigger frame 525. In certain embodiments, as described above, the
start time field can be predetermined (e.g, after SIFS or PIFS)
following the trigger frame.
[0096] The common info field 518 may include a length field 520a,
cascade indication 520b, he-sig-a information field 520c, a CP and
LTF Type field 520d, a trigger type field 520e, and a trigger
dependent common info field 520f. The length field 520a of the
Common Info field 518 may indicate the value of the L-SIG Length
field of the HE trigger-based PPDU that is the response to the
Trigger frame. If the cascade indication field 520b is 1, then a
subsequent Trigger frame follows a current Trigger frame. Otherwise
the Cascade Indication field 520b is zero (0). The HE-SIG-A Info
field 520c may indicate the content of the HE-SIG-A field of the HE
trigger-based PPDU response. The TBD bits in HE-SIG-A of the HE
trigger-based PPDU that may be implicitly known by all responding
STAs can be excluded. The CP and LTF Type field 520d may indicate
the CP and HE-LTF type of the HE trigger-based PPDU response. The
Trigger Type field 520e indicates the type of the Trigger frame.
The Trigger frame can include an optional type-specific Common Info
and optional type-specific Per User Info.
[0097] FIG. 5C is an exemplary response frame to a frame that was
at least in part a corrupted frame. In some aspects, the response
frame 550 may take the form of an acknowledgment frame, block
acknowledgment frame, or negative acknowledgment frame. The
response frame 550 may include the frame control field 507,
duration field 552, receiver address field 554, protection
indication field 556, start time field 558, transmission parameters
field 560, and frame check sequence field 562. In some aspects the
response frame may be a control response frame that carries an HT
Control field, where in the HT Control field may carry the
transmission parameters and the other fields.
[0098] In some aspects, the response frame 550 may be transmitted
in response to receiving a frame requesting protection for a
wireless communication exchange. For example, in some aspects, the
response frame 550 may be transmitted in response to receiving a
frame 500 with the more fragment field 512f set to a value of one
(1) (or another value), requesting protection for a remaining
portion of a wireless communication exchange.
[0099] The protection indication field 556 may indicate whether a
transmitter of the response frame 550 will cause a network
allocation vector (NAV) to be set to protect a remaining portion of
a wireless communication exchange. For example, in some aspects,
the response frame 550 may acknowledge a data packet having a more
data field, such as more data field 512i in frame 500 of FIG. 5A,
with a value set to one (1) (or another value is other aspects). If
the protection indication field 556 is set to a one, it may
indicate the transmitter of the response frame 550 will cause the
NAV to be set for a time period estimated to be sufficient to
complete the data transfer of data that is part of the data
communication exchange. The data communication exchange may include
the transfer of data from a data sending device to a data receiving
device. The data sending device may be addressed by the response
frame 550 (for example, by the receiver address field 554 of the
response frame 550 (not shown) may identify the data sending
device). The data receiving device may be the device transmitting
the response frame 550.
[0100] The transmission parameters field 560 may include at least
one or more of a modulation and coding scheme (MCS) 564a,
transmission bandwidth information 564b, and channel information
564c such as channel allocation information. In some aspects,
values in the transmission parameters field 560 may indicate how a
subsequent transmission, performed under the protection indicated
by protection indication field 556, is to be performed.
[0101] FIG. 6 is a method of wireless communication. In some
aspects, process 600 may be performed by either a station or an
access point. For example, process 600 may be performed by the AP
104 described with respect to FIGS. 3 and 4A-B above. In some
aspects, the process 600 may be performed by the wireless device
202, described above with respect to FIG. 2. For example,
instructions stored in the memory 206 may configure the processor
204 to perform one or more of the functions discussed below with
respect to process 600.
[0102] Process 600 may allow a device receiving one or more frames
from another device that would otherwise be transmitted/received
during a contention period to instead initiate protection for those
frames by causing a network allocation vector to be set. Once the
network allocation vector is set, the frames may then be
transmitted/received under the protection from collisions provided
by the NAV. This protection may be especially valuable when the
receiving device is within a dense network environment, where the
probability of packet collisions is relatively high. By initiating
protection of the wireless communication exchange, a receiver can
better ensure successful completion of the communication exchange
at an acceptable packet loss/efficiency level. Note that while the
descriptions refer to a NAV protection mechanism, in some other
aspects, the protection may be provided by any other protection
mechanism, such as setting the duration field of the L-SIG field of
the frame initiating the exchange, etc.
[0103] In block 605, a first wireless frame is received. The first
wireless frame is received by a receiving device. The first
wireless frame is part of a wireless communication exchange between
a transmitting device and the receiving device. A wireless
communication exchange may include an exchange of messages between
two devices, the receiving device and a transmitting device, with
each of the messages having an association with each other. For
example, a data packet and an acknowledgment of the data packet may
form a wireless communication exchange in some aspects. In some
other aspects, a series of data frames including one or more
additional data frames, with each eventually including a more data
indication, except for perhaps a last data frame of the series,
along with one or more acknowledgment frames acknowledging the
transmitted data frames may form another wireless communication
exchange in some aspects. In some aspects the acknowledgment
packets may be block acknowledgment frames. In some aspects, the
wireless communication exchange may be a series of data packets
exchanged in both uplink and downlink between an access point and
one or more associated STAs. In some aspects, a wireless
communication exchange duration may be equivalent to a duration of
a remaining transmission opportunity.
[0104] The first wireless frame may be received during a contention
period on the wireless network, in that the frame is not
transmitted/received while a network allocation vector is set for
one or more of the receiving device and the transmitting device. In
some other aspects, the network allocation vector may be set when
the first wireless frame is transmitted/received. For example, the
device transmitting the first wireless frame may have performed a
RTS/CTS exchange prior to transmitting the first wireless frame.
However, one or more stations on the wireless medium may not have
received the RTS/CTS exchange and thus do not have their network
allocation vector set. For example, a station within proximity of
the receiving device may not have its network allocation vector
set, such that it may transmit at least partially concurrently with
the transmission/reception of the first wireless frame. In some
aspects the first wireless frame may be exchanged during
(re-)association or be part of a negotiation between two
devices.
[0105] In some aspects, block 605 includes determining that the
received first wireless frame includes one or more errors. In some
aspects, the determination that the received first wireless frame
includes errors may cause the receiving device to initiate
protection of a remaining portion of the wireless communication
exchange as described below.
[0106] In some aspects, block 605 includes determining that the
received frame contained a buffer size field in a QoS control
field, such as the QOS control field 511 in FIG. 5A, indicating a
non-zero value. In some aspects, this determination may cause the
receiving device to initiate protection of a remaining portion of
the wireless communication exchange as described below. One or more
of the functions discussed above with respect to block 605 may be
performed by one or more of the receiver 212 and/or processor
204.
[0107] In some aspects, block 605 includes decoding the first
wireless frame to determine the transmitted device requests that
the receiving device protect the wireless medium for a remaining
portion of the wireless communication exchange. For example, in
some aspects, the received frame may substantially conform to the
format of frame 500, shown above with respect to FIG. 5A. In these
aspects, a device performing process 600 may decode the more
fragment field 512f to determine if a transmitting device of the
frame 500 requested that the receiving device initiate protection
for a data communications exchange including the frame 500. As
mentioned above the field can be the Retry field, or any other
field in the frame (potentially it could be in the PHY header as
well).
[0108] In some aspects, block 605 includes decoding the frame to
determine one or more transmission parameters.
[0109] The transmission parameters of the received frame may be
located in a physical (PHY) header of the received frame. The PHY
header of the received frame may include one or more of the
following parameters (though not limited to) MCS, bandwidth, number
of spatial streams (NSS), PPDU duration, NAV duration, a
transmitter identifier, a receiver identifier, a direction of the
frame (e.g., UL or DL), use of low density parity check (LDPC) or
binary convolutional code (BCC), subchannel index within the
bandwidth used for transmitting the payload (i.e., the (A-)MPDU),
SU/MU mode, and/or Basic Service Set (BSS) color (identifier).
[0110] In some aspects, these parameters may include a request for
the receiving device to initiate medium access and/or initiate
protection of at least a portion of one or multiple communication
exchanges as described below. Some aspects the request may include
a periodicity, a number of communication exchanges to be initiated
and other parameters that help the receiving device determine the
duration of time for protecting the one or more communication
exchanges.
[0111] In some aspects of block 605, a response to the first
wireless frame, such as a third wireless frame, is transmitted. The
response wireless frame may be generated to indicate that the
receiving device will enable protection for a remaining portion for
the wireless communication exchange. For example, in some aspects,
the response frame may conform to the format shown in FIG. 5C as
response frame 550. In some aspects, the protection indication
field 556 may be used to indicate whether the receiving device will
enable protection.
[0112] Enabling protection includes transmitting one or more
messages to cause a network allocation vector (NAV) to be set, such
that the wireless medium is reserved for transmissions associated
with the wireless communication exchange. The indication in the
response frame may be in the form of one or more bits, allocated
into one or more fields of the response frame, that have particular
values. The particular values may be predefined, for example, via a
wireless communication standard, to provide the indication
described above. For example, in some aspects, the response frame
may conform to the format shown in FIG. 5C as response frame 550.
In some aspects, the protection indication field 556 may be used to
indicate whether the receiving device will enable protection. In
some aspects, the more fragment field 512f may be set to a
particular value to indicate the receiving device will enable
protection as described above. Other fields may also be used for
this purpose in various aspects. In received frame aspects that
include transmission parameters as discussed above, the response
may include confirmation of transmission parameters or provide
alternative parameters, for example but not limited to a modulation
and coding scheme (MCS), number of spatial streams (NSS), PPDU
duration, a periodicity and number of frames that may be sent to
provide protection to the device transmitting the first frame.
[0113] In some aspects, the response frame is generated to include
a second indication of an estimated time when the receiving device
will initiate protection of the remaining portion of the wireless
communication exchange. For example, in some aspects, the second
indication is a time offset from the time the response frame is
transmitted, for example, as shown by start time field 558 of FIG.
5C.
[0114] In some aspects, the response frame is generated to indicate
one or more transmission parameters for the transmitting device to
use when retransmitting at least a portion of the first wireless
frame. For example, the response frame may indicate an updated MCS,
bandwidth parameters or alternative channel information, such as a
suggestion to use a particular secondary channel or subchannel. An
example of this is shown above with respect to transmission
parameters field 560, and transmission bandwidth fields 564a-c. In
some aspects, the response frame is generated to indicate a
duration of time for which protection will be established. For
example, in some aspects, the duration may be stored in the
duration field 552.
[0115] In some aspects, the response frame is generated as an
acknowledgment frame, a block acknowledgment frame, or a negative
acknowledgment frame. A negative acknowledgment frame in some
aspects may be indicated via an acknowledgment frame that has one
or more fields in a frame control field that are set to non-zero
values. For example, in one aspect, a negative acknowledgment frame
is generated to have a retry field 512g of the frame control field
507 set to a value of one. In some aspects, a negative
acknowledgment frame or a block acknowledgment frame is generated
when block 605 determines that the received frame includes errors.
For example, a block acknowledgment frame may selectively not
acknowledge the received frame if it included errors. In some
aspects, one or more of the functions discussed above with respect
to block 605 may be performed by the transmitter 210 and/or
processor 204. In some aspects, multiple response frames may be
generated, one or more of which as part of a (re-) negotiation, and
one or more as part of responses to received frames transmitted by
the requesting devices. In some aspect no response frame may be
generated. In some aspects, the transmitter may interpret the lack
of a response frame as an implicit acknowledgment. In some aspects
the response frame contains an HT Control field.
[0116] In block 615, a second frame is transmitted during a
contention period. The second frame may be generated as a
clear-to-send frame in some aspects. For example, the type/subtype
field 512b/512c of the frame control field 507 may be set to values
defined in the 802.11 standard that indicate the frame is a clear
to send frame. The second frame may be addressed to the
transmitting device, for example, via an address field 509 or 516
in a media access control header of the clear-to-send frame. The
second wireless frame protects the wireless medium for a time
period. For example, in some aspects, the time period is determined
by the receiving device to be adequate (greater than or equal to) a
time required to complete a remaining portion of the wireless
communication exchange. The time period may be of a duration
sufficient to protect a remaining portion of the wireless
communication exchange from packet collisions.
[0117] For example, in aspects where the second wireless frame is a
clear-to-send frame, a duration field (such as duration field 528)
of the clear-to-send (CTS) frame may indicate a period of time
during which the network allocation vector should (or shall) be set
by STAs to which the CTS frame is not addressed. In these aspects,
the duration field 528 may indicate a period of time during which
receiver device to which the CTS frame is addressed may transmit
one or more frames addressed to the transmitter of the second
wireless frame. In some aspects, the device to which the CTS is
addressed may transmit to any other STA during that duration of
time. In some aspects the device to which the CTS is addressed
should discard or otherwise ignore any previous NAV setting.
[0118] In some other aspects, the second frame may be generated as
a trigger frame. For example, the trigger frame may have
type/subtype values in the frame control field 507 that identify
the frame as a trigger frame via an 802.11 standard (and not as a
clear to send frame for example). The trigger frame may also
include an indication of a time period during which the network
allocation vector should be set by STAs that are not the intended
receivers of the trigger frame. In some aspects, the trigger frame
is generated to include a transmission schedule. The transmission
schedule may indicate timing parameters associated with the
transmission of one or more frames to be transmitted by the device
that transmitted the first wireless frame. In some aspects, the
receiving device may receive packets from multiple devices during
the time period allocated for protection by the trigger frame. In
some aspects, the receiving device may receive the multiple packets
from multiple devices using multi-user mode, such as MU-MIMO or
OFDMA. For example, as shown in FIG. 5B, the trigger frame 525 may
include a series of information indicating schedule information for
a particular device. For example, the device identifier field 532
indicates that information is for a particular device. Channel
information field 534 indicates which channel a transmission should
be performed on, and start time field 536 indicates when the
transmission should begin. The fields 532, 534, 536 may be of a
fixed length such that a device receiving the trigger frame 525 can
parse through a number of fixed length records to see if it is
identified by any of the fields 532a-n. In some aspects, one or
more of the functions discussed above with respect to block 615 may
be performed by one or more of the processor 204 and/or the
transmitter 210.
[0119] In block 620, a remaining portion of the wireless
communication exchange is received from the transmitting device
under the protection established by the second frame. In some
aspects, block 620 may include receiving one or more data packets.
For example, in some aspects, if errors were detected in the first
wireless frame and a negative acknowledgment was sent to the
transmitting device as described above with respect to some aspects
of block 605, then block 620 may include receiving a retransmission
of the first wireless frame and acknowledging the retransmission.
If the first wireless frame included a more data indication, then
block 620 may include receiving one or more additional data frames,
with one or more of these additional data frames also including a
more data indication (except perhaps a last packet). The additional
data frames may then be acknowledged via one or more block
acknowledgments as part of block 620. The reception and/or
transmission of frames in block 620 occurs under the protection
from collisions provided by the NAV set as a result of functions
performed during block 615. One or more of the functions discussed
above with respect to block 620 may be performed by a combination
of one or more of the processor 204, receiver 212, and/or
transmitter 210.
[0120] FIG. 7 is a flowchart of a method of wireless communication.
In some aspects, process 700 may be performed by either a station
or an access point. For example, process 700 may be performed by
the STA 106a described with respect to FIGS. 3, 4A and 4B. In some
aspects, the process 700 may be performed by the wireless device
202, described above with respect to FIG. 2. For example, in some
aspects, the memory 206 may store instructions that configure the
processor 204 to perform one or more of the functions discussed
below with respect to process 700. In some aspects, the process 700
is performed by a device transmitting data to a receiving device,
which is performing process 700.
[0121] Process 700 may allow a device transmitting data to receive
an indication from a device receiving the data that the receiving
device will initiate protection of data transfer from the
transmitting device to the receiving device. For example,
ordinarily, one or more of the frames would be transmitted during a
contention period. However, using the disclosed methods and
systems, the transmitting device receives an indication from the
receiving device that the receiving device will initiate protection
for those frames (for example, by causing a network allocation
vector (NAV) to be set). This indication is received in a frame
that is different than a frame actually requesting the network
allocation vector (NAV) to be set.
[0122] Once the network allocation vector is set, the transmitting
device resumes its transmission of frames to the receiving device.
These remaining frames are transmitted under the protection from
collisions provided by the NAV set by the receiving device. This
protection may be especially valuable when the receiving device is
within a dense network environment, where the probability of packet
collisions near the receiving device is relatively high. By
initiating protection of the wireless communication exchange
between the transmitting device and receiving device, the receiving
device can increase the likelihood of completion of the
communication exchange at an acceptable packet loss/efficiency
level. Note that while the description above and below generally
refers to protection by setting a network allocation vector (NAV),
other aspects may provide protection via any other protection
mechanism. For example, some aspects may set the duration field of
an L-SIG field of a frame initiating the communication exchange in
order to provide protection.
[0123] In block 705, a first wireless frame is transmitted on a
wireless medium. The frame is transmitted to a receiving device by
a transmitting device. The first wireless frame forms at least a
portion of a wireless communication exchange between the
transmitting device and the receiving device. For example, in some
aspects, the first wireless frame may be one of a series of data
packets, which, along with corresponding acknowledgments or block
acknowledgments for the one or more data packets, form a wireless
communication exchange. In these aspects, some of the data packets
or one or more wireless frames may include a more data indication.
In some aspects, the first wireless frame does not include a more
data indication. In some aspects, a wireless communication exchange
may be equivalent to a duration of a remaining transmission
opportunity. In some aspects, one or more of the functions
discussed above with respect to block 705 may be performed by the
transmitter 210 and/or the processor 204.
[0124] In some aspects, the first wireless frame is generated to
include one or more transmission parameters. For example, the first
wireless frame may be generated to indicate a request for a device
receiving the first wireless frame to initiate medium access and/or
initiate protection for at least a portion of one or more
communication exchanges. In some aspects, the request may indicate
a periodicity, a number of communication exchanges to be initiated
by the receiving device, and other parameters that may assist the
receiving device in determining a duration of time that protection
should be established for one or more communication exchanges.
[0125] The transmission parameters of the first message may be
located in a physical (PHY) header of the first message. The PHY
header of the first message may include one or more of the
following parameters (though not limited to) MCS, bandwidth, number
of spatial streams (NSS), PPDU duration, NAV duration, a
transmitter identifier, a receiver identifier, a direction of the
frame (e.g., UL or DL), use of low density parity check (LDPC) or
binary convolutional code (BCC), subchannel index within the
bandwidth used for transmitting the payload (i.e., the (A-)MPDU),
SU/MU mode, and/or Basic Service Set (BSS) color/identifier.
[0126] In some aspects of block 705, a response frame is received
from the receiving device. The response frame may indicate the
receiving device will initiate protection for a remaining portion
of the wireless communication exchange. For example, in some
aspects, the response frame may conform to the format of response
frame 550, discussed above with respect to FIG. 5C. In some
aspects, the response frame is decoded as one of an acknowledgment,
block acknowledgment, or negative acknowledgment of the first
wireless frame. In response to receiving a negative acknowledgment
from the receiving device, the transmitting device may record or
mark the first wireless frame as requiring a retransmission once
the protection is established. If the first frame is acknowledged
by the response frame (for example, by a block acknowledgment or a
regular acknowledgment), then the first frame may be marked as
completed and may not be retransmitted by the transmitting device.
In some aspects, one or more of the functions discussed above with
respect to block 705 may be performed by the receiver 212 and/or
the processor 204.
[0127] Some aspects that receive a third wireless fame, such as a
response frame as described above, may defer additional
communications relating to the wireless communication exchange
until the protection indicated by the response frame is
established. This may include, in response to the third wireless
frame, deferring further transmissions until the NAV is set. For
example, if the response frame indicates an estimated time for
protection to be established (for example, via start time field
558), the transmitting device may defer additional communications
relating to the wireless communication exchange until at least the
time indicted. In some aspects, a fixed or predetermined deferral
period may be used.
[0128] In some aspects, the response frame may be decoded to
determine an amount of time for which protection will be
established. For example, in some aspects the duration field 552
may be decoded to determine an amount of time for which protection
will be established. In some aspects, one or more transmission
parameters may be decoded from the response frame. For example, in
some aspects, the transmission parameters field 560 shown in FIG.
5C may be decoded. In some aspects, the transmission parameters
field 560 may be at least in partial response to transmission
parameters included in the first wireless frame. For example, the
response frame 550 may confirm one or more of a periodicity and
number of frames that may be sent by the receiving device under
protection provided by the transmitting device.
[0129] The response may also be decoded to determine one or more of
an updated modulation and coding scheme (MCS) (such as provided by
transmission bandwidth field 564a), transmission bandwidth
parameters (such as provided by transmission bandwidth field 564b)
or alternative channel information (as provided by transmission
bandwidth field 564c), such as channel allocation information or a
suggestion to use a particular secondary channel may be decoded
from the response frame. In some aspects, the receiving device may
utilize these transmission parameters in future communications with
the device transmitting the response frame.
[0130] In some aspects, multiple response frames may be received.
In some aspects, one or more of these multiple response frames may
be part of a renegotiation, and one or more may be part of
responses to received frames transmitted by the transmitting
device. In some other aspects, no response frame may be received.
In these aspects, lack of a response frame may be determined to be
an implicit acknowledgment.
[0131] One or more of the functions discussed above with respect to
block 705 may be performed, in some aspects, by a combination of
one or more of the processor 204 and/or transmitter 210.
[0132] In block 715, a second wireless frame protecting the
wireless medium is received from the receiving device. In some
aspects, this second wireless frame may conform with the trigger
frame 525 shown in FIG. 5B. In some aspects, the second wireless
frame is decoded as a clear-to-send (CTS) frame or a trigger frame.
For example, in some aspects, the clear-to-send (CTS) frame may be
received by the transmitting device in block 715. If the CTS frame
is not addressed to the transmitting device, the CTS frame
indicates a network allocation vector (NAV) should be set. In some
aspects, a duration field 528 of the clear-to-send frame indicates
a time period the NAV should be set. The duration field 528 may be
decoded by the transmitting device to determine how long its own
network allocation vector should be set. If the CTS frame is
addressed to the transmitting device (i.e. the device receiving the
CTS frame), the CTS is an indication that protection is now
established, and a remaining portion of the pending wireless
communication exchange can be completed during the protection
period. A duration field 528 of the CTS frame may indicate how much
time is available to complete the wireless communication
exchange.
[0133] In some aspects, a trigger frame is received in block 715,
indicating that protection has been established for a remaining
portion of the wireless communication exchange. In some aspects,
the trigger frame is decoded to determine a transmission schedule,
such as transmission schedule 530 shown in FIG. 5B. The
transmission schedule 530 may indicate a time when one or more
frames are to be transmitted to the receiving device. For example,
as shown in trigger frame 525, the transmission schedule 530 may
indicate channel information 534 and/or start time information 536
for a device identified by the device id field 532. In some
aspects, information for multiple devices may be present in then
transmission schedule 530. The trigger frame may also include an
indication of a duration of the protection for the wireless
communication exchange, i.e. how long the network allocation vector
(NAV) should be set by devices to which the trigger frame is not
addressed.
[0134] In block 720, a remaining portion of the wireless
communication exchange is completed under the protection
established by the frame received in block 715. In some aspects,
once protection is established, completing the wireless
communication exchange may include retransmitting one or more data
packets to the receiving device. In some aspects, the
retransmission of the one or more data packets may be based on
transmission parameters decoded from the optional response frame
discussed above with respect to block 705. In some aspects, if the
transmitting device previously received a negative acknowledgment
for the first wireless frame transmitted in block 705, completing
the wireless communication exchange may include retransmitting the
first wireless frame and receiving an acknowledgment for the first
wireless frame from the receiving device.
[0135] In some aspects, completing transmission of the wireless
communication exchange may include transmitting one or more
additional data frames including "more data" indications to the
receiving device, and receiving corresponding acknowledgments, such
as one or more block acknowledgments for the one or more
transmitted data frames from the receiving device. In these
aspects, the first wireless frame may have been generated with a
more data indication as well.
[0136] In some aspects, completing transmission of the wireless
communication exchange may also include transmission of one or more
packets to other devices besides the receiving device. For example,
in some aspects, the trigger frame discussed above may identify a
time period when a transmission should be initiated to the
receiving device. During the indicated time, the transmitting
device may also transmit data to other devices, for example, via
the use of multi-user multiple input multiple output (MU-MIMO) or
orthogonal frequency division multiple access (OFDMA).
[0137] In some aspects, one or more of the functions discussed
above with respect to block 720 may be performed by one or more of
the processor 204 and/or transmitter 210 and/or receiver 212.
[0138] FIG. 8A shows one organization of a wireless frame. Frame
800 includes a physical header 805, and one or more of the
following: a media access control (MAC) header 815, payload 820,
and a frame check sequence (FCS) field 825, and padding (not
shown). The frame 800 includes a variety of data that may be used
to determine whether the frame is addressed to a particular device
that may receive the frame. For example, in some aspects the
physical header 805 may contain one or more of a partial
association identifier for the addressed (intended) receiving
device, a partial association identifier for the device
transmitting the frame, a basic service set color indication,
typically a basic service set identifier of a device transmitting
the frame, and/or an indication of whether the frame is UL or
DL.
[0139] The media access control (MAC) header 815 may also include
one or more indications of an intended receiver of the frame. For
example, the media access control header 815 may include an address
field (A1) indicating a station address or other identifier of the
intended receiver device (i.e. the device to which the frame is
"addressed"). The MAC header 815 may also include an address field
indicating a station address or other identifier of the
transmitting device. The MAC header 815 may also include an address
field indicating the basic service set identifier of the
transmitting device. One or more of these fields in the frame 800
may be used to determine an intended receiver of the frame 800 in
the event that the frame 800 becomes partially corrupt due to, for
example, a collision with another frame on a wireless medium. An
example of such a process is described below with respect to FIG.
9.
[0140] FIG. 8B shows another organization of a wireless frame 850.
The frame 850 includes a physical header 855, a plurality of A-MPDU
subframes, shown in the example of FIG. 8B as A-MPDU subframe 860a
and A-MPDU subframe 860b, and optional padding 865. Each of the
A-MPDU subframes included in frame 850 may include an MPDU
delimiter field 870, an MPDU 875 (including a MAC header, payload,
and frame check sequence field, which are not shown in FIG. 8B),
and an optional pad field 880.
[0141] The frame 850 includes a variety of data that may be used to
determine whether the frame is addressed to a particular device
that may receive the frame. For example, in some aspects the
physical header 855 may contain one or more of a partial
association identifier for the addressed (intended) receiving
device, a partial association identifier for the device
transmitting the frame, and a basic service set color indication,
typically a basic service set identifier of a device transmitting
the frame, an indication whether the frame is UL or DL.
[0142] Each of the media access control (MAC) headers 815 in the
frame 850 may also include one or more indications of an intended
receiver of the frame. For example, the media access control header
815 may include an address field (A1) indicating a station address
or other identifier of the intended receiver device (i.e. the
device to which the frame is "addressed"). The MAC header 815 may
also include an address field indicating a station address or other
identifier of the transmitting device. The MAC header 815 may also
include an address field indicating the basic service set
identifier of the transmitting device. One or more of these fields
in the frame 850 may be used to determine an intended receiver of
the frame 800 in the event that the frame 850 becomes partially
corrupt due to, for example, a collision with another frame on a
wireless medium. An example of such a process is described below
with respect to process 900.
[0143] FIG. 9 is a flowchart of a method of determining whether a
frame that includes errors is addressed to a device receiving the
frame. For example, although errors caused by packet collisions may
corrupt at least portions of a received frame, other portions of
the frame may remain uncorrupted. By decoding the uncorrupted
portions of the frame, a device receiving the frame may be able to
determine whether the corrupted frame was addressed to the
receiving device or not. This information may be used to determine
whether the receiving device should initiate protection for a
communication exchange between itself and a device transmitting the
corrupted frame, as discussed above.
[0144] In some aspects, process 900 may be performed by any of the
wireless device 202 of FIG. 2, AP 104 or STA 106a-b of FIGS. 1, and
3-4A-B. For example, in some aspects, each of the blocks discussed
below may be performed by the processor 204. In some aspects, the
frame discussed below may substantially conform with one or more of
the characteristics of the frame 800 or frame 850, discussed above
with respect to FIGS. 8A-B.
[0145] In block 905, a frame received by a receiving device may be
determined to include one or more errors. For example, in some
aspects, a frame check sequence field, such as any one of frame
check sequence field 513, 535, 562, or 825 of FIGS. 5A-C or FIGS.
8A-B, respectively may be used to verify the integrity of the
received frame as is known in the art. This integrity check may
determine that the received frame includes at least one error. The
frame received in block 905 may be transmitted by a transmitting
device, which may be an access point or a station in various
aspects.
[0146] Decision block 910 determines whether the frame includes an
identifier identifying the receiving device. In some aspects the
identifier may be at least a portion of an association identifier,
such as a partial association identifier. For example, the partial
association identifier of the receiving device, as illustrated in
FIGS. 8A-B, may be included in a physical header 805 or 855 of the
frames 800 and 850 respectively. The receiving device may determine
whether a partial association identifier (AID) or (PAID) included
in the frame is at least a partial match to an AID assigned to the
receiving device during a previous association with an access
point. In some aspects the (partial) AID included in the frame is
at least a partial match to a MAC address of the receiving
device.
[0147] In some aspects, a partial match may require one or more
bits of the (partial) AID in the frame to match corresponding bits
in an AID previously assigned to the receiving device. In some
aspects, all bits of the partial AID of the frame must match a
previously assigned AID in order for a match to be determined in
decision block 910. In other aspects, fewer than all the bits may
be required to match. For example, 4, 5, 6, 7, 8, 9, 10, 11, 12,
13, 14, 15, or 16 bits of the (partial) AID in the frame must match
a previously assigned AID for a match to be determined in decision
block 910.
[0148] Functions performed in block 910 may vary across
embodiments. For example, in some aspects, the identifier
referenced in block 910 may actually be comprised of at least
portions of multiple fields included in the received frame. For
example, in some aspects, a PHY header of the received frame may
not have the identifier of the receiving device as discussed with
respect to block 910. In some aspects, the received frame may
include a transmitter association identifier (e.g. partial or full
association identifier) field and/or a basic service set color
field, and/or an uplink/downlink indication. In some aspects, the
receiving device may determine the received frame is intended for
or addressed to the receiving device based on a combination of one
or more of these fields.
[0149] If the frame does not include at least a partial match with
a previously assigned AID, process 900 moves to block 930, which
determines the frame is not addressed to the receiving device.
Otherwise, in some aspects, decision block 910 may also inspect one
or more media access control headers included in the frame to
determine whether an address field identifies the receiving device.
For example, as illustrated in frame 800 of FIG. 8A, the media
access control header 815 may include an address field (A1) that
identifies an intended receiver of the frame. If this identifier
identifies the receiving device (i.e. the device performing process
900), then decision block 910 may determine a match has occurred.
If no correctly received MAC header address field (such as an
address field 509 of FIG. 5A, 516 of FIG. 5B, or the A1 field shown
in MAC header 815 identifies the receiving device, process 900
moves to block 930, which determines the frame is not addressed to
the receiving device.
[0150] Otherwise, process 900 moves to decision block 915, which
determines whether the frame includes identification of a device
transmitting the frame, and whether that device is a "known"
transmitting device. A known transmitting device may be a device
that the receiving device (i.e. the device performing process 900)
has previously exchanged frames with. For example, any device with
which the receiving device is associated would be a known
transmitting device.
[0151] In some aspects the transmitter identifier may be at least a
portion of an association identifier or at least a portion of a MAC
address of a known transmitting device. For example, the device
performing process 900 may maintain a data store of association
identifiers and/or MAC addresses of devices it has previous
communicated with. If a transmitter's association identifier (e.g.
partial or full association identifier) (TAID) value included in
the received frame (such as the partial TAID shown in the physical
header 805 of frame 800 of FIG. 8A) does not at least partially
match a known transmitting device, process 900 moves from decision
block 915 to block 930, which determines the received frame is not
addressed to the receiving device. Otherwise, if the TAID of the
received frame is at least a partial (or complete) match with a
known transmitting device, then some aspects of process 900 may
also inspect a media access control (MAC) header included in the
frame to determine whether an address field, such as an A2 field
(such as second address field 510 shown in FIG. 5A) identifies a
known transmitting device. If no correctly received MAC header
address field (such as the second address field 510) identifies a
known transmitting device in these aspects, process 900 moves from
decision block 915 to block 930, which determines the received
frame is not addressed to the receiving device. Otherwise, process
900 moves to decision block 920.
[0152] Decision block 920 determines whether the frame includes a
basic service set identifier which is equivalent to at least a
portion of the receiving device's basic service set identifier. If
it does not, process 900 moves to block 930, which determines the
received frame is not addressed to the receiving device. If the
frame does include at least a portion of the basic service set
(BSS) identifier of the receiving device, process 900 moves to
block 925, which determines the frame is addressed to the receiving
device. In some aspects the basic service set (BSS) identifier is
included in the physical (PHY) header, such as a physical layer
convergence protocol (PLCP) header. Some aspects of block 925 may
infer one or more additional values from the frame. For example, a
transmission opportunity (TXOP) duration specified in the PHY
header, for example in an L-SIG, SIG-A/B/C field, a length of a PHY
Service Data Unit (PSDU) as specified in the PHY header, for
example in the L-SIG, SIG-A/B/C field, a modulation and coding
scheme (MCS), and other parameters useful for future scheduling of
the protected TXOP may be inferred from the received frame's PHY
header or other portions of the frame.
[0153] Some aspects of process 900 further include block 930, which
responds to the transmitting device based on the received frame
being addressed to the receiving device. For example, in some
aspects, block 930 may include one or more functions of process
600, discussed above with respect to FIG. 6. For example, in some
aspects, the received frame of block 905 may be the same frame as
the first wireless frame referenced in block 605.
[0154] While process 900 shown in FIG. 9 and described above
provides at least one example implementation, other implementations
of determining whether a frame that includes errors is addressed to
a device receiving the frame are also contemplated. For example, in
some aspects, an access point may be able to determine whether a
frame is addressed to it in a different manner than a station. For
example, in some aspects, if an access point can successfully
decode that the received frame is an uplink frame (for example, via
an uplink/downlink indicator in the frame), and a basic service set
color indication in the frame is a match for the access point's
color, then the access point may determine the frame is addressed
to it. In some aspects, the access point may decode an association
identifier (e.g. partial or full association identifier) of the
transmitter of the received frame from the received frame. If the
decoded association identifier field corresponds to records of
association identifiers the access point has used to communicate
with an associated station, then this determination may contribute
to a determination that the received frame was intended for or
addressed to the access point. In some aspects, the access point
may decode a receiver association identifier field (e.g. partial or
full association identifier) from the received frame. If the value
in this field matches an association identifier of the access
point, the association identifier field may contribute to a
determination that the received frame is intended for or addressed
to the access point.
[0155] A station may determine a received frame is intended for or
addressed to it using some of the same fields used by an access
point but may also utilize different fields. For example, in some
aspects, a station may determine whether a partial association
identifier of an intended receiver, and a BSS color field
(identifier of the basic service set), of a downlink frame
indicates the frame is addressed to the station. For example, if
the association identifier (e.g. partial or full association
identifier) of the receiver field corresponds to the station's
partial association identifier, and the BSS color field of the
received frame matches a BSS color of an associated access point,
the station may determine the received frame is addressed to it. In
some other aspects, a station may rely only on BSS color indication
in a downlink frame. In some aspects, the station may also decode a
transmitter address of the received frame, if it is not corrupted.
The station may determine whether the transmitter address
corresponds to a device (e.g. access point) with which the station
is associated. If it does, this may further confirm that the
received frame was intended for or addressed to the station.
[0156] In some of the above aspects, the station may decode an
association identifier of the transmitter (e.g. partial or full
association identifier) in the received frame. If the decoded
transmitter partial association identifier field corresponds to
records of partial association identifier of transmitters the
station has used to communicate with an associated access point,
then this determination may contribute to a determination that the
received frame was intended for or addressed to the station.
[0157] In some aspects, process 900 may include transmitting a
clear-to-send frame or a trigger frame. In some aspects, the
clear-to-send or trigger frame may be addressed to the receiving
device (in that a destination address field identifies the
receiving device). By transmitting the clear-to-send frame or the
trigger frame, the receiving device may signal to the transmitting
device that it should allocate resources for transmission of
frames, including a retransmission of the frame received in block
905, to the receiving device.
[0158] As used herein, the term "determining" encompasses a wide
variety of actions. For example, "determining" may include
calculating, computing, processing, deriving, investigating,
looking up (e.g., looking up in a table, a database or another data
structure), ascertaining and the like. Also, "determining" may
include receiving (e.g., receiving information), accessing (e.g.,
accessing data in a memory) and the like. Also, "determining" may
include resolving, selecting, choosing, establishing and the like.
Further, a "channel width" as used herein may encompass or may also
be referred to as a bandwidth in certain aspects.
[0159] As used herein, 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, b, c, a-b, a-c, b-e, and a-b-c.
[0160] 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. For example, the functional
means may include a processor and memory operably coupled to the
processor, the memory storing instructions that configure to the
processor to perform the described functions.
[0161] 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 (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.
[0162] 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). In
addition, in some aspects computer readable medium may comprise
transitory computer readable medium (e.g., a signal). Combinations
of the above should also be included within the scope of
computer-readable media.
[0163] 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.
[0164] The functions described may be implemented in hardware,
software, firmware or any combination thereof. If implemented in
software, the functions may be stored as one or more instructions
on a computer-readable medium. 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. Disk and disc, as used herein, include compact disc (CD),
laser disc, optical disc, digital versatile disc (DVD), floppy
disk, and Blu-ray.RTM. disc where disks usually reproduce data
magnetically, while discs reproduce data optically with lasers.
[0165] 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.
[0166] Software or instructions may also be transmitted over a data
communications 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 data communications
medium.
[0167] Further, it should be appreciated that 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.
[0168] 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.
[0169] 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.
* * * * *