U.S. patent application number 16/600369 was filed with the patent office on 2020-02-06 for early detection procedure of high-efficiency frame and decision timing for spatial reuse.
The applicant listed for this patent is NEWRACOM, INC.. Invention is credited to Ahmad Reza HEDAYAT, Young Hoon KWON, Dae Won LEE, Sungho MOON, Yujin NOH.
Application Number | 20200045637 16/600369 |
Document ID | / |
Family ID | 58690657 |
Filed Date | 2020-02-06 |
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United States Patent
Application |
20200045637 |
Kind Code |
A1 |
NOH; Yujin ; et al. |
February 6, 2020 |
EARLY DETECTION PROCEDURE OF HIGH-EFFICIENCY FRAME AND DECISION
TIMING FOR SPATIAL REUSE
Abstract
In wireless communications, a station associated with a first
wireless network may perform early detection of a high-efficiency
(HE) frame for spatial reuse (SR). The station may determine a
received power of a legacy preamble of the HE frame when the frame
is associated with a second wireless network. The station may
reduce the received power by a predetermined value. The station may
initiate an SR transmission, when the reduced power is less than an
overlapping basic service set (OBSS) packet detection level. The
station may obtain an SR parameter associated with a second
station, where the SR parameter is based on a transmission power
level and an interference level at the second station, and initiate
an SR transmission, based on the SR parameter and the reduced
power. Other methods, apparatus, and computer-readable media are
also disclosed.
Inventors: |
NOH; Yujin; (Irvine, CA)
; LEE; Dae Won; (Portland, OR) ; MOON; Sungho;
(San Jose, CA) ; KWON; Young Hoon; (Laguna Niguel,
CA) ; HEDAYAT; Ahmad Reza; (Aliso Viejo, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NEWRACOM, INC. |
Lake Forest |
CA |
US |
|
|
Family ID: |
58690657 |
Appl. No.: |
16/600369 |
Filed: |
October 11, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15356496 |
Nov 18, 2016 |
10470128 |
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16600369 |
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62405530 |
Oct 7, 2016 |
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62400563 |
Sep 27, 2016 |
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62382168 |
Aug 31, 2016 |
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62346229 |
Jun 6, 2016 |
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62338986 |
May 19, 2016 |
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62333083 |
May 6, 2016 |
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62257116 |
Nov 18, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 52/0245 20130101;
Y02D 70/22 20180101; H04W 52/0229 20130101; H04L 27/0006 20130101;
Y02D 70/142 20180101; Y02D 30/70 20200801; H04W 84/12 20130101;
H04L 27/2602 20130101 |
International
Class: |
H04W 52/02 20060101
H04W052/02; H04L 27/00 20060101 H04L027/00; H04L 27/26 20060101
H04L027/26 |
Claims
1. A wireless device, associated with a first wireless network, for
facilitating spatial reuse, the wireless device comprising: one or
more memories; and one or more processors coupled to the one or
more memories, the one or more processors configured to cause:
processing a frame received from a station; determining whether the
frame is associated with a second wireless network; determining a
first received power, based on a legacy preamble portion of the
frame, when the frame is associated with the second wireless
network; adjusting the first received power by an adjustment value;
and initiating a spatial reuse transmission based on the adjusted
first received power.
2. The wireless device of claim 1, wherein the one or more
processors are configured to cause: determining whether the
adjusted first received power is less than an overlapping basic
service set (OBSS) packet detection (PD) level, wherein the spatial
reuse transmission is initiated when the adjusted first received
power is less than the OBSS PD level.
3. The wireless device of claim 1, wherein the one or more
processors are configured to cause: determining that the frame is a
high-efficiency (HE) extended range single-user (SU) physical layer
protocol data unit (PPDU) format, wherein the adjusting the first
received power by the adjustment value is performed in response to
determining that the frame is a HE extended range SU PPDU
format.
4. The wireless device of claim 1, wherein adjusting the first
received power comprises decreasing the first received power by
three (3) decibel (dB).
5. The wireless device of claim 1, wherein the one or more
processors are configured to cause: determining a second received
power based on a non-legacy preamble portion of the frame, wherein
the legacy preamble portion of the frame is a first received long
training field of the frame and the non-legacy preamble portion of
the frame is a second received long training field of the frame;
and passing the first received power from a physical layer of the
wireless device to a media access control layer of the wireless
device.
6. The wireless device of claim 1, wherein the first received power
comprises a received signal strength indicator (RSSI) value
associated with the legacy preamble portion of the frame.
7. The wireless device of claim 1, wherein the one or more
processors are configured to cause: revising a network allocation
vector (NAV) timer based on a comparison between the adjusted first
received power and an overlapping basic service set (OBSS) packet
detection (PD) level.
8. The wireless device of claim 1, wherein the one or more
processors are configured to cause: setting a network allocation
vector (NAV) timer when the adjusted first received power is equal
to or greater than an overlapping basic service set (OBSS) packet
detection (PD) level.
9. The wireless device of claim 1, wherein processing the frame
comprises: decoding a high-efficiency signal-A (HE-SIG-A) field of
the frame; obtaining contents from the HE-SIG-A field, the contents
containing color information; and wherein determining whether the
frame is associated with the second wireless network comprises
determining that the frame is associated with the second wireless
network based on the color information.
10. The wireless device of claim 9, wherein when the color
information does not match with color information associated with
the first wireless network, the frame is an inter-basic service set
(inter-BSS) frame.
11. The wireless device of claim 3, wherein the one or more
processors are configured to cause: determining a format of the
frame based on a length field of a legacy signal (L-SIG) field of
the frame and a high-efficiency signal-A (HE-SIG-A) field of the
frame.
12. The wireless device of claim 11, wherein when dividing a value
of the length field of the L-SIG field of the frame by three
produces a remainder of two and a second orthogonal frequency
division modulation (OFDM) symbol of the HE-SIG-A field of the
frame indicates quadrature binary phase-shift keying (QBPSK)
modulation, the frame is a HE extended range SU PPDU format.
13. The wireless device of claim 1, wherein a medium condition
associated with the wireless device is indicated to be busy during
a period of time for the wireless device to determine whether the
frame is an inter-basic service set (inter-BSS) frame.
14. A wireless device for facilitating spatial reuse in a first
wireless network, the wireless device comprising: one or more
memories; and one or more processors coupled to the one or more
memories, the one or more processors configured to cause:
processing a first frame and a second frame of a frame exchange
between a first station and a second station, the second frame
being responsive to the first frame of the frame exchange;
determining that one or more of the first frame and the second
frame are associated with a second wireless network; obtaining a
received power measured based on a portion of the first frame when
one or more of the first frame and the second frame are associated
with the second wireless network; adjusting the received power by a
predetermined value; obtaining a spatial reuse parameter associated
with the first station, wherein the spatial reuse parameter is
based on a transmission power level at the first station and an
interference level at the first station; and initiating a spatial
reuse transmission based on the spatial reuse parameter and the
adjusted received power.
15. The wireless device of claim 14, wherein determining that one
or more of the first frame and the second frame are associated with
the second wireless network comprises: determining that the first
frame is associated with the second wireless network based on color
information in a high-efficiency signal-A (HE-SIG-A) field of the
first frame or based on a match between either a transmit address
or a receive address in a media access control (MAC) header of the
first frame; and determining that the second frame is associated
with the second wireless network based on color information in the
HE-SIG-A field of the second frame or based on a match between
either a transmit address or a receive address in a MAC header of
the second frame.
16. The wireless device of claim 14, wherein obtaining the spatial
reuse parameter comprises obtaining the spatial reuse parameter
from a high-efficiency signal-A (HE-SIG-A) field of the second
frame.
17. The wireless device of claim 14, wherein the one or more
processors are configured to cause: determining that the first
frame is a high-efficiency (HE) extended range single-user (SU)
physical layer protocol data unit (PPDU) format, wherein the
adjusting the received power by the predetermined value is
performed in response to determining that the first frame is a HE
extended range SU PPDU format.
18. The wireless device of claim 14, wherein initiating the spatial
reuse transmission is performed when a transmission power level by
the wireless device is less than a difference between the spatial
reuse parameter and the adjusted received power.
19. The wireless device of claim 14, wherein the first frame is a
trigger frame, and the second frame is an uplink (UL) trigger based
frame.
20. A computer-implemented method, comprising: processing a frame
received from a station; determining that the frame is an
inter-basic service set (inter-BSS) frame associated with a second
wireless network; determining that the frame is carried in a
high-efficiency (HE) extended range single-user (SU) physical
protocol data unit (PPDU); obtaining a received power measurement
based on legacy preamble symbols of the frame; decreasing the
received power by a predetermined value to compensate for a power
boost factor when the received power is compared to an
overlapping-BSS (OBSS) packet detection (PD) level; and initiating
a spatial reuse transmission associated with the wireless device,
based on the decreased received power when the adjusted received
power is less than the OBSS PD level.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application of U.S.
application Ser. No. 15/356,496, entitled "EARLY DETECTION
PROCEDURE OF HIGH-EFFICIENCY FRAME AND DECISION TIMING FOR SPATIAL
REUSE," filed on Nov. 18, 2016, which claims the benefit of
priority from U.S. Provisional Application No. 62/257,116, entitled
"EARLY DETECTION PROCEDURE OF LEGACY FRAME AND HE FRAME FOR SR,"
filed Nov. 18, 2015; U.S. Provisional Application No. 62/333,083,
entitled "EARLY DETECTION PROCEDURE OF LEGACY FRAME AND DECISION
TIMING FOR SR," filed May 6, 2016; U.S. Provisional Application No.
62/338,986, entitled "EARLY DETECTION PROCEDURE OF LEGACY FRAME AND
DECISION TIMING FOR SR," filed May 19, 2016; U.S. Provisional
Application No. 62/346,229, entitled "EARLY DETECTION PROCEDURE OF
LEGACY FRAME AND DECISION TIMING FOR SR," filed Jun. 6, 2016; U.S.
Provisional Application No. 62/382,168, entitled "EARLY DETECTION
PROCEDURE OF LEGACY FRAME AND DECISION TIMING FOR SR," filed Aug.
31, 2016; U.S. Provisional Application No. 62/400,563, entitled
"EARLY DETECTION PROCEDURE OF LEGACY FRAME AND DECISION TIMING FOR
SR," filed Sep. 27, 2016; and U.S. Provisional Application No.
62/405,530, entitled "EARLY DETECTION PROCEDURE OF LEGACY FRAME AND
DECISION TIMING FOR SR," filed Oct. 7, 2016, each of which is
incorporated herein by reference in their entirety.
TECHNICAL FIELD
[0002] The present description relates in general to wireless
communication systems and methods, and more particularly to, for
example, without limitation, early detection procedures of
high-efficiency frame and decision timing for spatial reuse.
BACKGROUND
[0003] Wireless local area network (WLAN) devices are deployed in
diverse environments. These environments are generally
characterized by the existence of access points and non-access
point stations. Increased interference from neighboring devices
gives rise to performance degradation. Additionally, WLAN devices
are increasingly required to support a variety of applications such
as video, cloud access, and offloading. In particular, video
traffic is expected to be the dominant type of traffic in many high
efficiency WLAN deployments. With the real-time requirements of
some of these applications, WLAN users demand improved performance
in delivering their applications, including improved power
consumption for battery-operated devices.
[0004] The description provided in the background section should
not be assumed to be prior art merely because it is mentioned in or
associated with the background section. The background section may
include information that describes one or more aspects of the
subject technology.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 illustrates a schematic diagram of an example of a
wireless communication network.
[0006] FIG. 2 illustrates a schematic diagram of an example of a
wireless communication device.
[0007] FIG. 3A illustrates a schematic block diagram of an example
of a transmitting signal processor in a wireless communication
device.
[0008] FIG. 3B illustrates a schematic block diagram of an example
of a receiving signal processor in a wireless communication
device.
[0009] FIG. 4 illustrates an example of a timing diagram of
interframe space (IFS) relationships.
[0010] FIG. 5 illustrates an example of a timing diagram of a
carrier sense multiple access/collision avoidance (CSMA/CA) based
frame transmission procedure for avoiding collision between frames
in a channel.
[0011] FIG. 6 illustrates an example of a high efficiency (HE)
frame.
[0012] FIGS. 7A through 7D illustrate examples of physical layer
convergence procedure (PLCP) protocol data unit (PPDU) formats.
[0013] FIG. 8 illustrates an example process of detecting a frame
and determining whether spatial reuse is allowed.
[0014] FIG. 9 illustrates an example of detecting a frame over
multiple decision times.
[0015] FIG. 10 illustrates another example of detecting a frame
over multiple decision times.
[0016] FIG. 11 illustrates an example of detecting a frame over
multiple decision times.
[0017] FIG. 12 illustrates an example of detecting a frame over
multiple decision times.
[0018] FIGS. 13A and 13B illustrate examples of detecting a frame
over multiple decision times.
[0019] FIG. 14 illustrates an example of detecting a frame for
spatial reuse.
[0020] FIGS. 15A and 15B illustrate examples of detecting an
inter-basic service set (inter-BSS) frame over multiple decision
times.
[0021] FIGS. 16 and 17 illustrate examples of detecting a frame
using an overlapping basic service set (OBSS) packet detection (PD)
level for spatial reuse.
[0022] FIG. 18 illustrates an example of frame formats in a normal
mode and a range extension mode for spatial reuse.
[0023] FIGS. 19A and 19B illustrate an example of detecting an
overlapping basic service set (OBSS) frame for spatial reuse.
[0024] FIGS. 20A and 20B illustrate an example of detecting an
overlapping basic service set (OBSS) frame for spatial reuse.
[0025] FIGS. 21A through 21D illustrate an example of detecting an
overlapping basic service set (OBSS) frame when beamforming is
applied for spatial reuse.
[0026] FIGS. 22A and 22B illustrate an example of detecting an
overlapping basic service set (OBSS) frame for spatial reuse.
[0027] FIGS. 23A and 23B illustrate an example of detecting an
overlapping basic service set (OBSS) frame for spatial reuse.
[0028] FIG. 24 illustrates an example of detecting an inter-BSS
frame during a period for initiating a spatial reuse
transmission.
[0029] FIGS. 25A, 25B, and 25C illustrate flow charts of examples
of methods for early detection procedure of high-efficiency frame
and decision timing for spatial reuse.
[0030] In one or more implementations, not all of the depicted
components in each figure may be required, and one or more
implementations may include additional components not shown in a
figure. Variations in the arrangement and type of the components
may be made without departing from the scope of the subject
disclosure. Additional components, different components, or fewer
components may be utilized within the scope of the subject
disclosure.
DETAILED DESCRIPTION
[0031] The detailed description set forth below is intended as a
description of various implementations and is not intended to
represent the only implementations in which the subject technology
may be practiced. As those skilled in the art would realize, the
described implementations may be modified in various different
ways, all without departing from the scope of the present
disclosure. Accordingly, the drawings and description are to be
regarded as illustrative in nature and not restrictive.
[0032] Early detection procedures for a frame (e.g., a
high-efficiency (HE) frame) provide new opportunities for
next-generation WiFi technology, including 802.11ax technology, for
spatial reuse (SR). In one or more implementations for achieving SR
in next generation WLAN technologies, a basic service set (BSS)
color field of a frame may be used to detect early on whether a
received frame is an inter-frame (e.g., originates from an
overlapping-BSS (OBSS) associated with a different wireless network
as that of a station (STA) detecting the received frame) or an
intra-frame (e.g., originates from a BSS associated with a same
wireless network as that of the STA detecting the received frame).
An early detection procedure can thus provide the ability to
determine whether a frame (e.g., an HE frame or a legacy frame) is
an inter-frame or intra-frame. In one or more implementations,
legacy frames are taken into account because some devices in the
market have design capabilities limited to earlier releases of IEEE
802.11 technologies.
[0033] Early frame detection for SR also may be achieved through
receiver power measurements at different decision time points under
a particular physical layer (PHY) procedure. Absent any early
detection, the SR mechanism may not allow earlier access to a
medium to transmit a PPDU, which is likely to give off some
interference to an inter-frame from an OBSS.
[0034] New multi-user (MU) transmissions, such as downlink (DL) and
uplink (UL) orthogonal frequency division multiple access (OFDMA)
and UL MU multiple-input/multiple-output (MIMO), are provided for
next-generation WiFi technology. For example, DL OFDMA is a
technique that can be used in WiFi technology in order to enhance
the aggregation of multiple payloads that are destined to multiple
STAs within the same frame. Due to this and other advantages, OFDMA
technique may be used for next generation WLAN technologies,
including 802.11ax, which is also referred to as HE technology. MU
transmission refers to cases that multiple resources are
transmitted to or from multiple STAs simultaneously. Examples of
the different resources may include different frequency resources
in OFDMA transmission and different spatial streams in MU-MIMO
transmission. Examples of MU transmissions may include DL-OFDMA,
DL-MU-MIMO, UL-OFDMA, and UL-MU-MIMO.
[0035] IEEE 802.11ax can support DL MU transmissions and UL MU
transmissions. In one or more implementations, UL MU physical layer
convergence procedure protocol data units (PPDUs) (e.g., over
MU-MIMO or OFDMA) are sent as a response to a trigger frame
transmitted by an access point (AP). A trigger frame may have
enough STA specific information and assigned resource units to
identify the STAs intended (or configured) to transmit UL MU PPDUs.
Efficient multiplexing acknowledgement-based transmissions in
response to DL MU PPDU or UL MU PPDU may be used as part of the
early detection procedure.
[0036] Moreover, IEEE 802.11ax can support features such as new
clear channel assessment (CCA) levels and deferral rules to improve
OBSS operation in dense environments, such that an STA can
determine whether the detected frame is an inter-BSS or an
intra-BSS frame. As mentioned above, the STA can detect a frame by
using a BSS color field in a high-efficiency signal-A (HE-SIG-A)
field or a medium access control (MAC) address in a MAC header of
the frame. If the detected frame is an inter-BSS frame, under one
or more specific conditions, the early detection procedure can
utilize a predetermined OBSS packet detection (PD) level. In one or
more implementations, if an OBSS PPDU is received and is determined
to be less than the predetermined OBSS PD level, then the medium is
determined to be available for use, provided that CCA indication
indicates that the medium is IDLE.
[0037] In one or more implementations, when an STA receives a
legacy PPDU, the STA may behave as follows:
[0038] The STA obtains a MAC address in the first MAC protocol data
unit (MPDU) (e.g., MAC frame) and uses the MAC address for early
frame detection before a cyclical redundancy check (CRC) is
performed. The STA compares the MAC addresses to an address
associated with a same BSS as that of the STA (which may be
referred to as "myBSS"). If it is determined that the MAC address
does not match the address associated with myBSS, the STA
determines that the received frame originates from OBSS temporally
(i.e., an inter-BSS frame). In one respect, the received frame is
considered as a "valid frame" or a frame with a "valid MAC header"
when the received frame is determined to be an OBSS frame (or
inter-BSS frame).
[0039] In one or more implementations, if the received frame is
determined to have a valid MAC header under a predetermined
condition, and if the received power (e.g., received signal
strength indicator (RSSI), received channel power indicator (RCPI),
etc.) is less than a predetermined OBSS PD level, the STA can
ignore updating a NAV timer. Thereafter, if the STA determines that
the medium condition indicates an IDLE channel (or IDLE) based on
channel sensing, the STA resumes a countdown process (e.g., a
countdown process or a decrementing process with respect to an
interframe space (IFS) time period, backoff, or a combination
thereof) to have the STA ready for an SR transmission. In one or
more implementations, if the received frame is determined not to
have a valid MAC header (i.e., intra-BSS frame), then the STA
concludes that the medium condition remains indicating a BUSY
channel (or BUSY).
[0040] In one or more implementations, when the STA receives a
frame (i.e., a non-legacy frame), the STA may behave as
follows:
[0041] The STA may check the contents in an HE-SIG-A field of the
received frame, and may obtain color information (e.g., color bits)
from the HE-SIG-A field. The STA may compare the color information
obtained to color information associated with the same BSS as that
of the STA. When the color information of the received frame does
not match the color information associated with myBSS, the STA may
conclude that the received frame is an inter-BSS frame. Otherwise,
the STA concludes that the received frame is an intra-BSS frame
(i.e., the color information match).
[0042] In the case of the STA determining that the received frame
is an inter-BSS frame, the STA measures the receive power (e.g.,
RSSI) in a legacy preamble of the received frame. The STA then
compares the measured received power of the received frame to the
predetermined OBSS PD level. If the measured received power is less
than the predetermined OBSS PD level, the STA can ignore updating
the NAV timer. Thereafter, the STA determines that the medium
condition indicates an IDLE channel based on channel sensing, the
STA resumes a countdown process (e.g., a countdown process or a
decrementing process with respect to an interframe space (IFS) time
period, backoff, or a combination thereof) to have the STA ready
for an SR transmission.
[0043] In one or more implementations, there are two SR conditions
to be considered before determining to initiate an SR transmission.
In one or more implementations, a first condition refers to an OBSS
PD based SR transmission, which corresponds to measuring a receive
power of a frame received from an OBSS STA. In this implementation,
the STA receives the frame and measures a receive power in a
preamble (or header) of the received frame. The STA then compares
the measured received power to a predetermined OBSS PD level. When
the measured received power is less than the predetermined OBSS PD
level, the STA determines that the medium condition indicates an
IDLE channel.
[0044] In one or more implementations, a second condition refers to
an opportunistic adaptive CCA (OA-CCA, which is sometimes referred
to as CCA-OA) based SR transmission, which takes into account an
interference level at an OBSS STA (e.g., a receiving OBSS STA) for
determining whether an SR transmission, initiated from the STA,
would adversely impact the OBSS STA. In this implementation, when
the STA receives the frame, the STA considers an estimated
interference level that is not expected to affect the OBSS STA in
order to determine a proper transmit power at the STA for
initiating the SR transmission. When the transmit power of the STA
is determined to be less than the power level that does not impact
the receiving OBSS STA, the STA determines that the medium
condition indicates an IDLE channel for the duration of the
received frame (i.e., up to the end of the frame).
[0045] FIG. 1 illustrates a schematic diagram of an example of a
wireless communication network 100. In the wireless communication
network 100, such as a wireless local area network (WLAN), a basic
service set (BSS) includes a plurality of wireless communication
devices (e.g., WLAN devices). In one aspect, a BSS refers to a set
of STAs that can communicate in synchronization, rather than a
concept indicating a particular area. In the example, the wireless
communication network 100 includes wireless communication devices
111-115, which may be referred to as STAs.
[0046] Each of the wireless communication devices 111-115 may
include a media access control (MAC) layer and a physical (PHY)
layer according to an IEEE 802.11 standard. In the example, at
least one wireless communication device (e.g., device 111) is an
access point (AP). An AP may be referred to as an AP STA, an AP
device, or a central station. The other wireless communication
devices (e.g., devices 112-115) may be non-AP STAs. Alternatively,
all of the wireless communication devices 111-115 may be non-AP
STAs in an Ad-hoc networking environment.
[0047] An AP STA and a non-AP STA may be collectively called STAs.
However, for simplicity of description, in some aspects, only a
non-AP STA may be referred to as an STA. An AP may be, for example,
a centralized controller, a base station (BS), a node-B, a base
transceiver system (BTS), a site controller, a network adapter, a
network interface card (NIC), a router, or the like. A non-AP STA
(e.g., a client device operable by a user) may be, for example, a
device with wireless communication capability, a terminal, a
wireless transmit/receive unit (WTRU), a user equipment (UE), a
mobile station (MS), a mobile terminal, a mobile subscriber unit, a
laptop, a non-mobile computing device (e.g., a desktop computer
with wireless communication capability) or the like. In one or more
aspects, a non-AP STA may act as an AP (e.g., a wireless
hotspot).
[0048] In one aspect, an AP is a functional entity for providing
access to a distribution system, by way of a wireless medium, for
an associated STA. For example, an AP may provide access to the
internet for one or more STAs that are wirelessly and
communicatively connected to the AP. In FIG. 1, wireless
communications between non-AP STAs are made by way of an AP.
However, when a direct link is established between non-AP STAs, the
STAs can communicate directly with each other (without using an
AP).
[0049] In one or more implementations, OFDMA-based 802.11
technologies are utilized, and for the sake of brevity, an STA
refers to a non-AP high efficiency (HE) STA, and an AP refers to an
HE AP. In one or more aspects, an STA may act as an AP.
[0050] FIG. 2 illustrates a schematic diagram of an example of a
wireless communication device. The wireless communication device
200 includes a baseband processor 210, a radio frequency (RF)
transceiver 220, an antenna unit 230, a memory 240, an input
interface unit 250, an output interface unit 260, and a bus 270, or
subsets and variations thereof. The wireless communication device
200 can be, or can be a part of, any of the wireless communication
devices 111-115.
[0051] In the example, the baseband processor 210 performs baseband
signal processing, and includes a medium access control (MAC)
processor 211 and a PHY processor 215. The memory 240 may store
software (such as MAC software) including at least some functions
of the MAC layer. The memory may further store an operating system
and applications.
[0052] In the illustration, the MAC processor 211 includes a MAC
software processing unit 212 and a MAC hardware processing unit
213. The MAC software processing unit 212 executes the MAC software
to implement some functions of the MAC layer, and the MAC hardware
processing unit 213 may implement remaining functions of the MAC
layer as hardware (MAC hardware). However, the MAC processor 211
may vary in functionality depending on implementation. The PHY
processor 215 includes a transmitting (TX) signal processing unit
280 and a receiving (RX) signal processing unit 290. The term TX
may refer to transmitting, transmit, transmitted, transmitter or
the like. The term RX may refer to receiving, receive, received,
receiver or the like.
[0053] The PHY processor 215 interfaces to the MAC processor 211
through, among others, transmit vector (TXVECTOR) and receive
vector (RXVECTOR) parameters. In one or more aspects, the MAC
processor 211 generates and provides TXVECTOR parameters to the PHY
processor 215 to supply per-packet transmit parameters. In one or
more aspects, the PHY processor 215 generates and provides RXVECTOR
parameters to the MAC processor 211 to inform the MAC processor 211
of the received packet parameters.
[0054] In some aspects, the wireless communication device 200
includes a read-only memory (ROM) (not shown) or registers (not
shown) that store instructions that are needed by one or more of
the MAC processor 211, the PHY processor 215 and/or other
components of the wireless communication device 200.
[0055] In one or more implementations, the wireless communication
device 200 includes a permanent storage device (not shown)
configured as a read-and-write memory device. The permanent storage
device may be a non-volatile memory unit that stores instructions
even when the wireless communication device 200 is off. The ROM,
registers and the permanent storage device may be part of the
baseband processor 210 or be a part of the memory 240. Each of the
ROM, the permanent storage device, and the memory 240 may be an
example of a memory or a computer-readable medium. A memory may be
one or more memories.
[0056] The memory 240 may be a read-and-write memory, a read-only
memory, a volatile memory, a non-volatile memory, or a combination
of some or all of the foregoing. The memory 240 may store
instructions that one or more of the MAC processor 211, the PHY
processor 215, and/or another component may need at runtime.
[0057] The radio frequency (RF) transceiver 220 includes an RF
transmitter 221 and an RF receiver 222. The input interface unit
250 receives information from a user, and the output interface unit
260 outputs information to the user. The antenna unit 230 includes
one or more antennas. When multi-input multi-output (MIMO) or
multi-user MIMO (MU-MIMO) is used, the antenna unit 230 may include
more than one antenna.
[0058] The bus 270 collectively represents all system, peripheral,
and chipset buses that communicatively connect the numerous
internal components of the wireless communication device 200. In
one or more implementations, the bus 270 communicatively connects
the baseband processor 210 with the memory 240. From the memory
240, the baseband processor 210 may retrieve instructions to
execute and data to process in order to execute the processes of
the subject disclosure. The baseband processor 210 can be a single
processor, multiple processors, or a multi-core processor in
different implementations. The baseband processor 210, the memory
240, the input interface unit 250, and the output interface unit
260 may communicate with each other via the bus 270.
[0059] The bus 270 also connects to the input interface unit 250
and the output interface unit 260. The input interface unit 250
enables a user to communicate information and select commands to
the wireless communication device 200. Input devices that may be
used with the input interface unit 250 may include any acoustic,
speech, visual, touch, tactile and/or sensory input device, e.g., a
keyboard, a pointing device, a microphone, or a touchscreen. The
output interface unit 260 may enable, for example, the display or
output of videos, images, audio, and data generated by the wireless
communication device 200. Output devices that may be used with the
output interface unit 260 may include any visual, auditory,
tactile, and/or sensory output device, e.g., printers and display
devices or any other device for outputting information. One or more
implementations may include devices that function as both input and
output devices, such as a touchscreen.
[0060] One or more implementations can be realized in part or in
whole using a computer-readable medium. In one aspect, a
computer-readable medium includes one or more media. In one or more
aspects, a computer-readable medium is a tangible computer-readable
medium, a computer-readable storage medium, a non-transitory
computer-readable medium, a machine-readable medium, a memory, or
some combination of the foregoing (e.g., a tangible
computer-readable storage medium, or a non-transitory
machine-readable storage medium). In one aspect, a computer is a
machine. In one aspect, a computer-implemented method is a
machine-implemented method.
[0061] A computer-readable medium may include storage integrated
into a processor and/or storage external to a processor. A
computer-readable medium may be a volatile, non-volatile, solid
state, optical, magnetic, and/or other suitable storage device,
e.g., RAM, ROM, PROM, EPROM, a flash, registers, a hard disk, a
removable memory, or a remote storage device.
[0062] In one aspect, a computer-readable medium comprises
instructions stored therein. In one aspect, a computer-readable
medium is encoded with instructions. In one aspect, instructions
are executable by one or more processors (e.g., 210, 211, 212, 213,
215, 280, 290) to perform one or more operations or a method.
Instructions may include, for example, programs, routines,
subroutines, data, data structures, objects, sequences, commands,
operations, modules, applications, and/or functions. Those skilled
in the art would recognize how to implement the instructions.
[0063] A processor (e.g., 210, 211, 212, 213, 215, 280, 290) may be
coupled to one or more memories (e.g., one or more external
memories such as the memory 240, one or more memories internal to
the processor, one or more registers internal or external to the
processor, or one or more remote memories outside of the device
200), for example, via one or more wired and/or wireless
connections. The coupling may be direct or indirect. In one aspect,
a processor includes one or more processors. A processor, including
a processing circuitry capable of executing instructions, may read,
write, or access a computer-readable medium. A processor may be,
for example, an application specific integrated circuit (ASIC), a
digital signal processor (DSP), or a field programmable gate array
(FPGA).
[0064] In one aspect, a processor (e.g., 210, 211, 212, 213, 215,
280, 290) is configured to cause one or more operations of the
subject disclosure to occur. In one aspect, a processor is
configured to cause an apparatus (e.g., a wireless communication
device 200) to perform operations or a method of the subject
disclosure. In one or more implementations, a processor
configuration involves having a processor coupled to one or more
memories. A memory may be internal or external to the processor.
Instructions may be in a form of software, hardware or a
combination thereof. Software instructions (including data) may be
stored in a memory. Hardware instructions may be part of the
hardware circuitry components of a processor. When the instructions
are executed or processed by one or more processors, (e.g., 210,
211, 212, 213, 215, 280, 290), the one or more processors cause one
or more operations of the subject disclosure to occur or cause an
apparatus (e.g., a wireless communication device 200) to perform
operations or a method of the subject disclosure.
[0065] FIG. 3A illustrates a schematic block diagram of an example
of a transmitting signal processing unit 280 in a wireless
communication device. The transmitting signal processing unit 280
of the PHY processor 215 includes an encoder 281, an interleaver
282, a mapper 283, an inverse Fourier transformer (IFT) 284, and a
guard interval (GI) inserter 285.
[0066] The encoder 281 encodes input data. For example, the encoder
281 may be a forward error correction (FEC) encoder. The FEC
encoder may include a binary convolutional code (BCC) encoder
followed by a puncturing device, or may include a low-density
parity-check (LDPC) encoder. The interleaver 282 interleaves the
bits of each stream output from the encoder 281 to change the order
of bits. In one aspect, interleaving may be applied only when BCC
encoding is employed. The mapper 283 maps the sequence of bits
output from the interleaver 282 into constellation points.
[0067] When MIMO or MU-MIMO is employed, the transmitting signal
processing unit 280 may use multiple instances of the interleaver
282 and multiple instances of the mapper 283 corresponding to the
number of spatial streams (N.sub.SS). In the example, the
transmitting signal processing unit 280 may further include a
stream parser for dividing outputs of the BCC encoders or the LDPC
encoder into blocks that are sent to different interleavers 282 or
mappers 283. The transmitting signal processing unit 280 may
further include a space-time block code (STBC) encoder for
spreading the constellation points from the number of spatial
streams into a number of space-time streams (N.sub.STS) and a
spatial mapper for mapping the space-time streams to transmit
chains. The spatial mapper may use direct mapping, spatial
expansion, or beamforming depending on implementation. When MU-MIMO
is employed, one or more of the blocks before reaching the spatial
mapper may be provided for each user.
[0068] The IFT 284 converts a block of the constellation points
output from the mapper 283 or the spatial mapper into a time domain
block (e.g., a symbol) by using an inverse discrete Fourier
transform (IDFT) or an inverse fast Fourier transform (IFFT). If
the STBC encoder and the spatial mapper are employed, the IFT 284
may be provided for each transmit chain.
[0069] When MIMO or MU-MIMO is employed, the transmitting signal
processing unit 280 may insert cyclic shift diversities (CSDs) to
prevent unintentional beamforming. The CSD insertion may occur
before or after the inverse Fourier transform operation. The CSD
may be specified per transmit chain or may be specified per
space-time stream. Alternatively, the CSD may be applied as a part
of the spatial mapper.
[0070] The GI inserter 285 prepends a GI to the symbol. The
transmitting signal processing unit 280 may optionally perform
windowing to smooth edges of each symbol after inserting the GI.
The RF transmitter 221 converts the symbols into an RF signal and
transmits the RF signal via the antenna unit 230. When MIMO or
MU-MIMO is employed, the GI inserter 285 and the RF transmitter 221
may be provided for each transmit chain.
[0071] FIG. 3B illustrates a schematic block diagram of an example
of a receiving signal processing unit 290 in a wireless
communication device. The receiving signal processing unit 290 of
the PHY processor 215 includes a GI remover 291, a Fourier
transformer (FT) 292, a demapper 293, a deinterleaver 294, and a
decoder 295.
[0072] The RF receiver 222 receives an RF signal via the antenna
unit 230 and converts the RF signal into one or more symbols. In
some aspects, the GI remover 291 removes the GI from the symbol.
When MIMO or MU-MIMO is employed, the RF receiver 222 and the GI
remover 291 may be provided for each receive chain.
[0073] The FT 292 converts the symbol (e.g., the time domain block)
into a block of the constellation points by using a discrete
Fourier transform (DFT) or a fast Fourier transform (FFT) depending
on implementation. In one or more implementations, the FT 292 is
provided for each receive chain.
[0074] When MIMO or MU-MIMO is employed, the receiving signal
processing unit 290 may further include a spatial demapper for
converting the Fourier transformed receiver chains to constellation
points of the space-time streams, and an STBC decoder (not shown)
for despreading the constellation points from the space-time
streams into the spatial streams.
[0075] The demapper 293 demaps the constellation points output from
the FT 292 or the STBC decoder to the bit streams. If the LDPC
encoding is used, the demapper 293 may further perform LDPC tone
demapping before the constellation demapping. The deinterleaver 294
deinterleaves the bits of each stream output from the demapper 293.
In one or more implementations, deinterleaving may be applied only
when BCC decoding is used.
[0076] When MIMO or MU-MIMO is employed, the receiving signal
processing unit 290 may use multiple instances on the demapper 293
and multiple instances of the deinterleaver 294 corresponding to
the number of spatial streams. In the example, the receiving signal
processing unit 290 may further include a stream deparser for
combining the streams output from the deinterleavers 294.
[0077] The decoder 295 decodes the streams output from the
deinterleaver 294 and/or the stream deparser. For example, the
decoder 295 may be an FEC decoder. The FEC decoder may include a
BCC decoder or an LDPC decoder.
[0078] FIG. 4 illustrates an example of a timing diagram of
interframe space (IFS) relationships. In this example, a data
frame, a control frame, or a management frame can be exchanged
between the wireless communication devices 111-115 and/or other
WLAN devices.
[0079] Referring to the timing diagram 400, during the time
interval 402, access is deferred while the medium (e.g., a wireless
communication channel) is busy until a type of IFS duration has
elapsed. At time interval 404, immediate access is granted when the
medium is idle for a duration that is equal to or greater than a
distributed coordination function IFS (DIFS) 410 duration or
arbitration IFS (AIFS) 414 duration. In turn, a next frame 406 may
be transmitted after a type of IFS duration and a contention window
418 have passed. During the time 408, if a DIFS has elapsed since
the medium has been idle, a designated slot time 420 is selected
and one or more backoff slots 422 are decremented as long as the
medium is idle.
[0080] The data frame is used for transmission of data forwarded to
a higher layer. In one or more implementations, a WLAN device
transmits the data frame after performing backoff if DIFS 410 has
elapsed from a time when the medium has been idle.
[0081] The management frame is used for exchanging management
information that is not forwarded to the higher layer. Subtype
frames of the management frame include a beacon frame, an
association request/response frame, a probe request/response frame,
and an authentication request/response frame.
[0082] The control frame is used for controlling access to the
medium. Subtype frames of the control frame include a request to
send (RTS) frame, a clear to send (CTS) frame, and an
acknowledgement (ACK) frame. In the case that the control frame is
not a response frame of the other frame (e.g., a previous frame),
the WLAN device transmits the control frame after performing
backoff if the DIFS 410 has elapsed. In the case that the control
frame is the response frame of the other frame, the WLAN device
transmits the control frame without performing backoff if a short
IFS (SIFS) 412 has elapsed. For example, the SIFS may be 16
microseconds. The type and subtype of frame may be identified by a
type field and a subtype field in a frame control field of the
frame.
[0083] On the other hand, a Quality of Service (QoS) STA may
transmit the frame after performing backoff if AIFS 414 for access
category (AC), e.g., AIFS[AC], has elapsed. In this case, the data
frame, the management frame, or the control frame that is not the
response frame may use the AIFS[AC].
[0084] In one or more implementations, a point coordination
function (PCF) enabled AP STA transmits the frame after performing
backoff if a PCF IFS (PIFS) 416 has elapsed. In this example, the
PIFS 416 duration is less than the DIFS 410 but greater than the
SIFS 412. In some aspects, the PIFS 416 is determined by
incrementing the SIFS 412 duration by a designated slot time
420.
[0085] FIG. 5 illustrates an example of a timing diagram of a
carrier sense multiple access/collision avoidance (CSMA/CA) based
frame transmission procedure for avoiding collision between frames
in a channel. In FIG. 5, any one of the wireless communication
devices 111-115 in FIG. 1 can be designated as one of STA1, STA2 or
STA3. In this example, the wireless communication device 111 is
designated as STA1, the wireless communication device 112 is
designated as STA2, and the wireless communication device 113 is
designated as STA3. While the timing of the wireless communication
devices 114 and 115 is not shown in FIG. 5, the timing of the
devices 114 and 115 may be the same as that of STA2.
[0086] In this example, STA1 is a transmit WLAN device for
transmitting data, STA2 is a receive WLAN device for receiving the
data, and STA3 is a WLAN device that may be located at an area
where a frame transmitted from STA1 and/or a frame transmitted from
STA2 can be received by STA3.
[0087] STA1 may determine whether the channel (or medium) is busy
by carrier sensing. STA1 may determine the channel occupation based
on an energy level on the channel or correlation of signals in the
channel. In one or more implementations, STA1 determines the
channel occupation by using a network allocation vector (NAV)
timer.
[0088] When determining that the channel is not used by other
devices during the DIFS 410 (e.g., the channel is idle), STA1 may
transmit an RTS frame 502 to STA2 after performing backoff. Upon
receiving the RTS frame 502, STA2 may transmit a CTS frame 506 as a
response of the CTS frame 506 after the SIFS 412.
[0089] When STA3 receives the RTS frame 502, STA3 may set a NAV
timer for a transmission duration representing the propagation
delay of subsequently transmitted frames by using duration
information involved with the transmission of the RTS frame 502
(e.g., NAV(RTS) 510). For example, STA3 may set the transmission
duration expressed as the summation of a first instance of the SIFS
412, the CTS frame 506 duration, a second instance of the SIFS 412,
a data frame 504 duration, a third instance of the SIFS 412 and an
ACK frame 508 duration.
[0090] Upon receiving a new frame (not shown) before the NAV timer
expires, STA3 may update the NAV timer by using duration
information included in the new frame. STA3 does not attempt to
access the channel until the NAV timer expires.
[0091] When STA1 receives the CTS frame 506 from STA2, STA1 may
transmit the data frame 504 to STA2 after the SIFS 412 elapses from
a time when the CTS frame 506 has been completely received. Upon
successfully receiving the data frame 504, STA2 may transmit the
ACK frame 508 after the SIFS 412 elapses as an acknowledgment of
receiving the data frame 504.
[0092] When the NAV timer expires, STA3 may determine whether the
channel is busy by the carrier sensing. Upon determining that the
channel is not used by the other WLAN devices (e.g., STA1, STA2)
during the DIFS 410 after the NAV timer has expired, STA3 may
attempt the channel access after a contention window 418 has
elapsed. In this example, the contention window 418 may be based on
a random backoff.
[0093] FIG. 6 illustrates an example of a high efficiency (HE)
frame 600. The HE frame 600 is a physical layer convergence
procedure (PLCP) protocol data unit (or PPDU) format. An HE frame
may be referred to as an OFDMA frame, a PPDU, a PPDU format, an
OFDMA PPDU, an MU PPDU, another similar term, or vice versa. An HE
frame may be simply referred to as a frame for convenience. A
transmitting station (e.g., AP, non-AP station) may generate the HE
frame 600 and transmit the HE frame 600 to a receiving station. The
receiving station may receive, detect, and process the HE frame
600. The HE frame 600 may include an L-STF field, an L-LTF field,
an L-SIG field, an RL-SIG field, an HE-SIG-A field, an HE-SIG-B
field, an HE-STF field, an HE-LTF field, and an HE-DATA field. The
HE-SIG-A field may include NHESIGA symbols, the HE-SIG-B field may
include NHESIGB symbols, the HE-LTF field may include NHELTF
symbols, and the HE-DATA field may include NDATA symbols. In an
aspect, the HE-DATA field may also be referred to as a payload
field, data, data signal, data portion, payload, PLCP service data
unit (PSDU), or MPDU.
[0094] In one or more implementations, an AP may transmit a frame
for downlink (DL) using a frame format shown in this figure or a
variation thereof (e.g., without any or some portions of an HE
header). A STA may transmit a frame for uplink (UL) using a frame
format shown in this figure or a variation thereof (e.g., without
any or some portions of an HE header).
[0095] The table below provides examples of characteristics
associated with the various components of the HE frame 600.
TABLE-US-00001 DFT Subcarrier Element Definition Duration period GI
Spacing Description Legacy(L)- Non-high 8 .mu.s -- -- equivalent
L-STF of a STF throughput to 1,250 kHz non-trigger- (HT) Short
based PPDU Training has a field periodicity of 0.8 .mu.s with 10
periods. L-LTF Non-HT 8 .mu.s 3.2 .mu.s 1.6 .mu.s 312.5 kHz Long
Training field L-SIG Non-HT 4 .mu.s 3.2 .mu.s 0.8 .mu.s 312.5 kHz
SIGNAL field RL-SIG Repeated 4 .mu.s 3.2 .mu.s 0.8 .mu.s 312.5 kHz
Non-HT SIGNAL field HE-SIG-A HE N.sub.HESIGA * 3.2 .mu.s 0.8 .mu.s
312.5 kHz HE-SIG-A is SIGNAL A 4 .mu.s duplicated on field each 20
MHz segment after the legacy preamble to indicate common control
information. N.sub.HESIGA means the number of OFDM symbols of the
HE-SIG-A field and is equal to 2 or 4. HE-SIG-B HE N.sub.HESIGB *
3.2 .mu.s 0.8 .mu.s 312.5 kHz N.sub.HESIGB SIGNAL B 4 .mu.s means
the field number of OFDM symbols of the HE-SIG-B field and is
variable. DL MU packet contains HE-SIG-B. Single user (SU) packets
and UL Trigger based packets do not contain HE-SIG-B. HE-STF HE
Short 4 or 8 .mu.s -- -- non- HE-STF of a Training trigger-
non-trigger- field based based PPDU PPDU: has a (equivalent
periodicity of to) 1,250 kHz; 0.8 .mu.s with 5 trigger- periods. A
non- based trigger-based PPDU: PPDU is not (equivalent sent in to)
625 kHz response to a trigger frame. The HE-STF of a trigger- based
PPDU has a periodicity of 1.6 .mu.s with 5 periods. A trigger-based
PPDU is a UL PPDU sent in response to a trigger frame. HE-LTF HE
Long N.sub.HELTF * 2xLTF: supports 2xLTF: HE PPDU Training (DFT 6.4
.mu.s 0.8 1.6 (equivalent may support field period + 4xLTF: 3.2
.mu.s to) 156.25 kHz; 2xLTF mode GI) .mu.s 12.8 .mu.s 4xLTF: and
4xLTF 78.125 kHz mode. In the 2xLTF mode, HE-LTF symbol excluding
GI is equivalent to modulating every other tone in an OFDM symbol
of 12.8 .mu.s excluding GI, and then removing the second half of
the OFDM symbol in time domain. N.sub.HELTF means the number of
HE-LTF symbols and is equal to 1, 2, 4, 6, 8. HE-DATA HE DATA
N.sub.DATA * 12.8 .mu.s supports 78.125 kHz N.sub.DATA means field
(DFT 0.8, 1.6, the number of period + 3.2 .mu.s HE data GI) .mu.s
symbols.
[0096] Referring to FIG. 6, the HE frame 600 contains a header and
a data field. The header includes a legacy header comprised of the
legacy short training field (L-STF), the legacy long training field
(L-LTF), and the legacy signal (L-SIG) field. These legacy fields
contain symbols based on an early design of an IEEE 802.11
specification. Presence of these symbols may facilitate
compatibility of new designs with the legacy designs and products.
The legacy header may be referred to as a legacy preamble. In one
or more aspects, the term header may be referred to as a
preamble.
[0097] In one or more implementations, the legacy STF, LTF, and SIG
symbols are modulated/carried with FFT size of 64 on a 20 MHz
sub-channel and are duplicated every 20 MHz if the frame has a
channel bandwidth wider than 20 MHz (e.g., 40 MHz, 80 MHz, 160
MHz). Therefore, the legacy field (i.e., the STF, LTF, and SIG
fields) occupies the entire channel bandwidth of the frame. The
L-STF field may be utilized for packet detection, automatic gain
control (AGC), and coarse frequency-offset (FO) correction. In one
aspect, the L-STF field does not utilize frequency domain
processing (e.g., FFT processing) but rather utilizes time domain
processing. The L-LTF field may be utilized for channel estimation,
fine frequency-offset correction, and symbol timing. In one or more
aspects, the L-SIG field may contain information indicative of a
data rate and a length (e.g., in bytes) associated with the HE
frame 600, which may be utilized by a receiver of the HE frame 600
to calculate a time duration of a transmission of the HE frame
600.
[0098] The header may also include an HE header comprised of an
HE-SIG-A field and an HE-SIG-B field. The HE header may be referred
to as a non-legacy header. These fields contain symbols that carry
control information associated with each PSDU and/or radio
frequency (RF), PHY, and MAC properties of a PPDU. In one aspect,
the HE-SIG-A field can be carried/modulated using an FFT size of 64
on a 20 MHz basis. The HE-SIG-B field can be carried/modulated
using an FFT size of e.g., 64 or 256 on a 20 MHz basis depending on
implementation. The HE-SIG-A and HE-SIG-B fields may occupy the
entire channel bandwidth of the frame. In some aspects, the size of
the HE-SIG-A field and/or the HE-SIG-B field is variable (e.g., can
vary from frame to frame). In an aspect, the HE-SIG-B field is not
always present in all frames. To facilitate decoding of the HE
frame 600 by a receiver, the size of (e.g., number of symbols
contained in) the HE-SIG-B field may be indicated in the HE-SIG-A
field. In some aspects, the HE header also includes the repeated
L-SIG (RL-SIG) field, whose content is the same as the L-SIG field.
In an aspect, the HE-SIG-A and HE-SIG-B fields may be referred as
control signal fields. In an aspect, the HE-SIG-A field may be
referred to as an SIG-A field, SIG-A, or simply SIGA. Similarly, in
an aspect, the HE-SIG-B field may be referred to as an SIG-B field,
SIG-B, or simply SIGB.
[0099] The HE header may further include HE-STF and HE-LTF fields,
which contain symbols used to perform necessary RF and PHY
processing for each PSDU and/or for the whole PPDU. The HE-LTF
symbols may be modulated/carried with an FFT size of 256 for 20 MHz
bandwidth and modulated over the entire bandwidth of the frame.
Thus, the HE-LTF field may occupy the entire channel bandwidth of
the frame. In one aspect, the HE-LTF field may occupy less than the
entire channel bandwidth. In one aspect, the HE-LTF field may be
transmitted using a code-frequency resource. In one aspect, an
HE-LTF sequence may be utilized by a receiver to estimate MIMO
channel between the transmitter and the receiver. Channel
estimation may be utilized to decode data transmitted and
compensate for channel properties (e.g., effects, distortions). For
example, when a preamble is transmitted through a wireless channel,
various distortions may occur, and a training sequence in the
HE-LTF field is useful to reverse the distortion. This may be
referred to as equalization. To accomplish this, the amount of
channel distortion is measured. This may be referred to as channel
estimation. In one aspect, channel estimation is performed using an
HE-LTF sequence, and the channel estimation may be applied to other
fields that follow the HE-LTF sequence.
[0100] The HE-STF symbols may have a fixed pattern and a fixed
duration. For example, the HE-STF symbols may have a predetermined
repeating pattern. In one aspect, the HE-STF symbols do not require
FFT processing. The HE frame 600 may include the data field,
represented as HE-DATA, that contains data symbols. The data field
may also be referred to as a payload field, data, payload or
PSDU.
[0101] In one or more aspects, additional one or more HE-LTF fields
may be included in the header. For example, an additional HE-LTF
field may be located after a first HE-LTF field. In one or more
implementations, a TX signal processing unit 280 (or an IFT 284)
illustrated in FIG. 3A may carry out the modulation described in
this paragraph as well as the modulations described in other
paragraphs above. In one or more implementations, an RX signal
processing unit 290 (or an FT 292) may perform demodulation for a
receiver.
[0102] FIGS. 7A through 7D illustrate examples of PPDU formats. In
or more implementations, four HE PPDU formats are defined: HE SU
PPDU (FIG. 7A), HE MU PPDU (FIG. 7B), HE extended range SU PPDU
(FIG. 7C) and HE trigger-based PPDU (FIG. 7D). In FIG. 7A, the
format of the HE SU PPDU is used for SU transmissions. The HE SU
PPDU format does not replicate the HE-SIG-A field. In FIG. 7B, the
format of the HE MU PPDU is used for MU transmissions (e.g., not in
response to a trigger frame). The HE MU PPDU format includes an
HE-SIG-B field. The size of (e.g., number of symbols contained in)
the HE-SIG-B field may be indicated in the HE-SIG-A field. In FIG.
7C, the format of the HE extended range SU PPDU is used for SU
transmissions. The HE extended range SU PPDU's HE-SIG-A field is
replicated (e.g., HE-SIG-A1, HE-SIG-A1', HE-SIG-A2, and
HE-SIG-A2'). In FIG. 7D, the format of the HE trigger-based PPDU is
used for MU transmissions that are in response to a trigger frame.
In this example, the HE trigger-based PPDU format does not
replicate the HE-SIG-A field.
[0103] FIG. 8 illustrates an example process of detecting a frame
and determining whether spatial reuse is allowed. When an STA
receives a frame (e.g., PPDU, HE frame) from a second STA, the
medium condition indicates a BUSY channel, and this BUSY channel
indication continues during the period of time that is taken by the
STA to validate that the frame is an inter-BSS frame (i.e., the
frame originates from an inter-BSS). During the same time period,
the STA may suspend a countdown process (e.g., a countdown or
decrementing process with respect to an interframe space (IFS) time
period, backoff, or a combination thereof, to have the STA ready
for an SR transmission).
[0104] During the same time period, the STA decodes the frame and
checks the contents of the HE-SIG-A field of the frame. The
contents of the HE-SIG-A field include a color field, which
contains color information (e.g., color bits). The STA compares the
obtained color information to the color information associated with
myBSS (i.e., BSS with which the STA is associated or to which the
STA belongs). When the color information in the HE-SIG-A field
matches with the color information associated with myBSS (i.e., the
frame originates from the same BSS as that of the STA), the STA
sets its local NAV timer. When the color information in the
HE-SIG-A field does not match the color information associated with
myBSS (i.e., the frame originates from a different BSS as that of
the STA), the STA identifies the frame as an inter-BSS frame. The
STA may increase an OBSS PD level to a predetermined level when the
color information is not matched.
[0105] The STA may obtain a received power associated with the
received frame. A received power may be represented as an RSSI
value. The STA may then compare the received power to the OBSS PD
level. When the STA determines that the received power is less than
the OBSS PD level, the STA ignores updating a NAV timer. Following
the comparison, if the medium condition indicates an IDLE channel
(e.g., medium condition transitions from a BUSY channel to an IDLE
channel) based on channel sensing, the STA resumes the countdown
process to have the STA ready to initiate an SR transmission. On
the other hand, when the STA determines that the received power is
greater than or equal to the OBSS PD level, the STA sets the NAV
timer.
[0106] FIG. 9 illustrates an example of detecting a frame over
multiple decision times. FIG. 9 describes the timing to measure the
received power in order to compare the measured received power to
the OBSS PD level for determining whether an SR transmission may be
initiated. As explained in FIG. 8, the measured received power is a
critical component and it can be measured several times through a
PHY receive procedure as illustrated in FIG. 9. In the legacy
preamble (e.g., L-STF, L-LTF), the received power (e.g., RSSI) can
be measured during the reception of the legacy PHY preamble. In one
or more implementations, the PHY includes the most recently
measured RSSI value in the PHY-RXSTART.indication(RXVECTOR)
primitive issued to the MAC. For an 802.11ac preamble, the received
power can be measured during the reception of the
very-high-throughput (VHT)-LTF field. In one or more
implementations, the measured received power (e.g., RSSI) changes
when beamforming is applied. In one or more implementations,
another frame signal measurement (e.g., RCPI) can be measured over
the entire received frame or other equivalent means that meets the
specified accuracy.
[0107] FIG. 10 illustrates another example of detecting a frame
over multiple decision times. Like in FIG. 9, there may be
different decision times to check the contents of the HE-SIG-A
field, and compare the measured received power to the OBSS PD
level. In FIG. 10, a first received power value is measured based
on the legacy preamble, and a first decision time occurs after
contents in the HE-SIG-A field are checked. A second received power
is measured based on the HE-LTF, and a second decision time occurs
after the second measured received power (beamforming applied). The
RCPI can be measured, and a third decision time occurs after
measuring the RCPI. In one or more implementations, the two
measured RSSI values can be determined based on the legacy preamble
and the HE-LTF field (under the 802.11ax specification), and the
RCPI value is a measurement of the received RF power in the
selected channel for a received frame. This parameter may be a
measurement by the PHY of the received RF power in the channel
measured over the entire received frame or by other equivalent
means that meet the specified accuracy.
[0108] FIG. 11 illustrates an example of detecting a frame over
multiple decision time. Based on a given decision time, the
received power measured at different decision times may differ such
that it may not be clear which measured received power should be
compared to the OBSS PD level to achieve SR. In addition to Case 1
shown, FIG. 11 describes two case scenarios (e.g., Case 2 and Case
3), which correspond to different measured RSSIs, resulting in
different SR procedures depending on the given decision time. For
example, an STA in Case 2 may set the NAV after determining that
the measured received power at decision time A exceeds the OBSS PD
level, whereas the STA may ignore updating the NAV timer after
determining that the measured received power at decision time B is
less than the OBSS PD level. The STA in Case 1 may ignore updating
the NAV timer based on the measured received power taken at either
decision times.
[0109] FIG. 12 illustrates an example of detecting a frame over
multiple decision times. Referring to Case 2 of FIG. 11, multiple
decision timing may be needed to avert a possible collision because
the frame can be an UL MU PPDU from an OBSS as described in FIG.
12, where the STA in myBSS (i.e., a same BSS to which the STA
belongs) receives another inter-BSS frame from an OBSS. Moreover,
the measured received power may be less than the OBSS PD level when
the decision time is set to the B position, where beamformed
received power is measured based on the HE-LTF. Because the
measured received power at decision time B satisfies the OBSS PD
based SR condition, the STA is expected to start a backoff counter
for initiating an SR transmission. Once the STA has a chance to
transmit the PPDU frame, there would be a collision, thus resulting
in a signal interference against the UL MU PPDU from other STAs
assigned by the trigger frame in the OBSS.
[0110] Referring to Case 3 of FIG. 11, given the decision time A to
compare a first measured RSSI based on the legacy preamble to the
OBSS PD level (where the measured received power is less than the
OBSS PD level), the medium condition indicates a transition to an
IDLE channel from a BUSY channel indication, and the STA resumes
the countdown process. During the DIFS or extended IFS (EIFS) time
periods, the STA may detect that the medium is occupied (i.e., a
BUSY channel).
[0111] FIGS. 13A and 13B illustrate examples of detecting a frame
over multiple decision times. In one or more implementations (which
may be referred to as "E8" simply for convenience), when an STA
receives a frame having color bits not matched to myBSS, the STA
may obtain the received power to be then used to compare against
the OBSS PD level.
[0112] The STA may compare the received power to the OBSS PD level.
When the STA determines that the received power is less than the
OBSS PD level, the STA ignores updating a NAV timer. Following the
comparison, if the medium condition indicates an IDLE channel
(e.g., medium condition transitions from a BUSY channel to an IDLE
channel) based on channel sensing, the STA resumes the countdown
process to have the STA ready to initiate an SR transmission.
[0113] In one or more implementations, when multiple received power
measurements are taken, certain mechanisms as follow may apply for
selecting the measured received power to compare to the OBSS PD
level: 1) take weighted sum of the two measured RSSI values, 2)
take minimum RSSI value among the measured RSSIs, and 3) each
measured RSSI value is used to compare to the OBSS PD level.
[0114] FIG. 14 illustrates an example of detecting a frame for
spatial reuse. In one or more implementations (which may be
referred to as "E9" simply for convenience), when an STA receives a
frame, the STA may behave as follows: The STA decodes the frame and
checks the contents of an HE-SIG field (e.g., HE-SIG-A field) of
the frame, where the contents in the HE-SIG field (e.g., HE-SIG-A
field) may include: 1) a color field, which contains color
information (e.g., color bits) to determine whether the frame is an
inter-frame or intra-frame, 2) a format indication to determine
whether the frame is a UL MU PPDU frame, and/or 3) the number of
HE-SIG-B symbol for selecting the decision time and corresponding
measured received power (e.g., if the length of the HE-SIG-B field
is too long to measure the RSSI based on the HE-LTF, then the
measured RSSI based on the legacy preamble may be used
instead).
[0115] The STA may obtain a received power associated with the
received frame. The STA may then compare the received power to the
OBSS PD level. When the STA determines that the received power is
less than the OBSS PD level, the STA ignores updating a NAV timer.
Following the comparison, if the medium condition indicates an IDLE
channel (e.g., medium condition transitions from a BUSY channel to
an IDLE channel) based on channel sensing, the STA resumes the
countdown process to have the STA ready to initiate an SR
transmission. On the other hand, when the STA determines that the
received power is greater than or equal to the OBSS PD level, the
STA sets the NAV timer.
[0116] FIGS. 15A and 15B illustrate examples of detecting an
inter-BSS frame over multiple decision times. In dense
circumstances, there may exist some cases that an STA may receive
more than one inter-frame, which is partially overlapped. When the
STA receives a frame, the STA determines whether the received frame
is an inter-frame, and the STA measures the received power of the
frame. The STA then compared the measured received power to the
OBSS PD level. In this example, the STA determines that the
measured received power is less than the OBSS PD level. During a
time in which the medium condition indicates an IDLE channel, the
start of a valid packet (or frame) is detected.
[0117] FIGS. 16 and 17 illustrate examples of detecting a frame
using an OBSS packet detection (PD) level for spatial reuse. In one
or more implementations (which may be referred to as "E11" simply
for convenience), when an STA receives a frame, the STA determines
that the received frame is an inter-frame (or inter-BSS frame). The
STA may then compare the measured received power to the OBSS PD
level. When the STA determines that the measured received power is
less than the OBSS PD level, the STA ignores updating a NAV timer.
Following the comparison, if the medium condition indicates an IDLE
channel (e.g., medium condition transitions from a BUSY channel to
an IDLE channel) based on channel sensing, the STA resumes the
countdown process to have the STA ready to initiate an SR
transmission. During the time that the medium condition indicates
an IDLE channel, the STA detects the start of a valid packet (or
frame). If the estimated packet detect CCA (or receive power) of
the second received inter-frame is also less than OBSS PD level,
the STA keeps the medium condition indicating an IDLE channel and
continues decrementing the backoff counter to zero, where the
estimated packet detect CCA (or received power) is calculated with
the first received inter-frame and overlapped OBSS PD level.
[0118] FIG. 18 illustrates examples of frame formats for spatial
reuse. In one or more implementations, the received power of L-STF
symbol(s) and L-LTF symbol(s) of the legacy preamble of a frame is
boosted by K dB (e.g., K=3) in the extended range preamble format
(e.g., 1802) by the transmitter to remove the performance
bottleneck in the legacy preamble. In this respect, the measured
received power (e.g., measured RSSI) of the legacy preamble can be
decreased by K dB when comparing to an OBSS PD level to determine
whether the STA is ready for initiating an SR transmission. If the
measured received power is not adjusted to reflect the boost in
power in the legacy preamble, then the system may lose the
opportunity to use the IDLE medium for an SR transmission.
[0119] In one or more implementations (which may be referred to as
"E12" simply for convenience), early detection of a frame (e.g.,
PPDU, HE frame, HE extended range SU PPDU) for spatial reuse is
performed by an STA using a procedure that measures a received
power of a legacy preamble portion (e.g., L-STF or L-LTF) of the
frame, adjusts the received power (if boosted), and compares the
power to an OBSS PD level. In one or more implementations, the
measured received power is passed from a PHY layer of the wireless
device to a MAC layer of the wireless device for processing.
[0120] When the STA receives a frame, which may be referred to as a
PPDU, HE frame, HE extended range SU PPDU, or another frame format
(e.g., trigger based frame format), from a second station, the
medium condition indicates a BUSY channel, and this BUSY channel
indication continues during the period of time that is taken by the
STA to determine whether the frame is an inter-BSS frame (i.e., the
frame originates from an inter-BSS) or an intra-BSS frame (i.e.,
the frame originates from a wireless network other than the
wireless network associated with the STA). During the same time
period, the STA may suspend a countdown process (e.g., a countdown
or decrementing process with respect to an interframe space (IFS)
time period, backoff, or a combination thereof, to have the STA
ready for an SR transmission).
[0121] In one embodiment, determining whether the received frame is
an inter-BS S or intra-BSS frame may include a comparison of color
information. For example, the STA decodes the frame and checks the
contents of the HE-SIG-A field of the frame. The contents of the
HE-SIG-A field may include a color field, which contains color
information (e.g., color bits). The color information describes a
BSS associated with the transmitting device (i.e., the second
station). The STA compares the obtained color information to the
color information associated with myBSS (i.e., BSS with which the
STA is associated or to which the STA belongs). When the color
information in the HE-SIG-A field matches with the color
information associated with myBSS (i.e., the frame originates from
the same BSS as that of the STA), the STA determines that the
received frame is an intra-BSS frame and sets its local NAV timer
based on the received frame. When the color information in the
HE-SIG-A field does not match the color information associated with
myBSS (i.e., the frame originates from a different BSS as that of
the STA), the STA identifies the frame as an inter-BSS frame. The
STA may increase an OBSS PD level by a predetermined level when the
color information is not matched. An OBSS PD level may be sometimes
referred to as a predetermined OBSS PD level, a PD level or a
threshold level.
[0122] The STA may obtain a received power measured based on a
legacy preamble (or header) portion of the received frame. In some
embodiments, the received frame may include two separate LTFs: (1)
an L-LTF and (2) an HE-LTF. Each of the two separate LTFs is
comprised of one or more symbols. In this embodiment, the L-LTF is
the legacy preamble such that the received power measured based on
the legacy preamble is based on the L-LTF of the frame. In one or
more implementations, the HE-LTF is the non-legacy preamble such
that a second received power measured based on the non-legacy
preamble is based on the HE-LTF of the frame. A received power may
be represented as an RSSI value. When the measured received power
is determined (e.g., by the STA) to have been boosted by a
predetermined value (e.g., K dB, where K may be 3), the STA adjusts
the measured received power by decreasing the measured received
power by a predetermined value (e.g., de-boosting the RSSI value by
the predetermined value, which may be K dB) before comparing the
measured received power to the OBSS PD level. In one or more
implementations, the adjustment to the measured received power by
the predetermined value is performed in response to determining
that the received frame is a HE extended range SU PPDU format.
[0123] The STA may then compare the adjusted received power (e.g.,
de-boosted RSSI) to the OBSS PD level. When the STA determines that
the adjusted received power is less than the OBSS PD level, the STA
ignores updating a NAV timer. Following the comparison, if the
medium condition indicates an IDLE channel (e.g., medium condition
transitions from a BUSY channel to an IDLE channel) based on
channel sensing, the STA resumes the countdown process to have the
STA ready to initiate an SR transmission. On the other hand, when
the STA determines that the adjusted received power is greater than
or equal to the OBSS PD level, the STA sets the NAV timer.
[0124] In one or more implementations, a received frame is in a
first type of frame format (e.g., an HE extended range SU PPDU
format) when a link margin available between one STA (e.g., AP) and
other STAs is insufficient, such that the received frame may be
more susceptible to signal interference. In one embodiment, the STA
may determine that the frame has been boosted by detecting that the
frame is an HE extended range SU PPDU format. This type of frame
may necessitate additional protection from a possible SR
transmission from an OBSS STA. This is described in more detail
below.
[0125] In an example, which may be a variation of E12, when an STA
receives a frame which is a first type of frame (i.e., an HE
extended range SU PPDU format), the STA obtains a received power
(e.g., received power measured based on a legacy preamble of the
received frame). A received power may be represented as an RSSI
value. When the measured received power is determined (e.g., by the
STA) to have been boosted by a predetermined value (e.g., K dB,
where K may be 3 when the frame is in an HE extended range SU PPDU
format), the STA adjusts the measured received power by increasing
the measured received power by a predetermined value (e.g.,
boosting the RSSI value by M dB) before comparing the measured
received power to the OBSS PD level. Under this condition, the STA
is not likely to allow an SR transmission when the STA receives an
HE extended range SU PPDU. Hence, an HE extended range SU PPDU can
be protected more than other HE PPDU formats from potential
interference by SR transmission.
[0126] The STA may then compare the adjusted received power (e.g.,
boosted RSSI) to the OBSS PD level. When the STA determines that
the adjusted received power is less than the OBSS PD level, the STA
ignores updating a NAV timer. Following the comparison, if the
medium condition indicates an IDLE channel (e.g., medium condition
transitions from a BUSY channel to an IDLE channel) based on
channel sensing, the STA resumes the countdown process to have the
STA ready to initiate an SR transmission. On the other hand, when
the STA determines that the adjusted received power is greater than
or equal to the OBSS PD level, the STA sets the NAV timer.
[0127] In one or more implementations (which may be referred to as
"E13" simply for convenience), early detection of a frame (e.g.,
PPDU, HE frame, HE extended range SU PPDU) for spatial reuse is
performed by an STA using a procedure that measures a received
power of a legacy preamble portion (e.g., L-STF or L-LTF) of the
frame, compares the received power to an OBSS PD level (adjusted
when the received power was boosted).
[0128] When the STA receives a frame (e.g., PPDU, HE frame, HE
extended range SU PPDU) from a second station, the medium condition
indicates a BUSY channel, and this BUSY channel indication
continues during the period of time that is taken by the STA to
validate that the frame is an inter-BSS frame (i.e., the frame
originates from an inter-BSS). During the same time period, the STA
may suspend a countdown process (e.g., a countdown or decrementing
process with respect to an interframe space (IFS) time period,
backoff, or a combination thereof, to have the STA ready for an SR
transmission).
[0129] During the same time period, the STA decodes the frame and
checks the contents of the HE-SIG-A field of the frame. The
contents of the HE-SIG-A field include a color field, which
contains color information (e.g., color bits). The STA compares the
obtained color information to the color information associated with
myBSS (i.e., BSS with which the STA is associated or to which the
STA belongs). When the color information in the HE-SIG-A field
matches with the color information associated with myBSS (i.e., the
frame originates from the same BSS as that of the STA), the STA
sets its local NAV timer. When the color information in the
HE-SIG-A field does not match the color information associated with
myBSS (i.e., the frame originates from a different BSS as that of
the STA), the STA identifies the frame as an inter-BSS frame. The
STA may increase an OBSS PD level to a predetermined level when the
color information is not matched. An OBSS PD level may be sometimes
referred to as a predetermined OBSS PD level, a PD level or a
threshold level.
[0130] The STA may obtain a received power measured based on a
legacy preamble (or header) portion of the received frame. A
received power may be represented as an RSSI value. When the
measured received power is determined (e.g., by the STA) to have
been boosted by a predetermined value (e.g., K dB, where K may be
3), the STA adjusts the OBSS PD level by increasing the OBSS PD
level by a predetermined value (e.g., boosting the OBSS PD level by
the predetermined value, which may be K dB) before comparing the
measured received power to the OBSS PD level.
[0131] The STA may then compare the measured received power to the
adjusted OBSS PD level. When the STA determines that the measured
received power is less than the adjusted OBSS PD level, the STA
ignores updating a NAV timer. Following the comparison, if the
medium condition indicates an IDLE channel (e.g., medium condition
transitions from a BUSY channel to an IDLE channel) based on
channel sensing, the STA resumes the countdown process to have the
STA ready to initiate an SR transmission. On the other hand, when
the STA determines that the measured received power is greater than
or equal to the adjusted OBSS PD level, the STA sets the NAV
timer.
[0132] In one or more implementations, a received frame is in a
first type of frame format (e.g., an HE extended range SU PPDU
format) when a link margin available between one STA (e.g., AP) and
other STAs is insufficient, such that the received frame may be
more susceptible to signal interference. This type of frame may
necessitate additional protection from a possible SR transmission
from an OBSS STA. This is described in more detail below.
[0133] In an example, which may be a variation of E13, when an STA
receives a frame which is a first type of frame (i.e., an HE
extended range SU PPDU format), the STA obtains a received power
(e.g., received power measured based on a legacy preamble of the
received frame). A received power may be represented as an RSSI
value. When the measured received power is determined (e.g., by the
STA) to have been boosted by a predetermined value (e.g., K dB,
where K may be 3), the STA adjusts the OBSS PD level by increasing
the OBSS PD level by a predetermined value (e.g., boosting the OBSS
PD value by M dB) before comparing the measured received power to
the OBSS PD level.
[0134] The STA may then compare the measured received power to the
adjusted OBSS PD level (e.g., boosted by M dB). When the STA
determines that the measured received power is less than the
adjusted OBSS PD level, the STA ignores updating a NAV timer.
Following the comparison, if the medium condition indicates an IDLE
channel (e.g., medium condition transitions from a BUSY channel to
an IDLE channel) based on channel sensing, the STA resumes the
countdown process to have the STA ready to initiate an SR
transmission. On the other hand, when the STA determines that the
measured received power is greater than or equal to the adjusted
OBSS PD level, the STA sets the NAV timer.
[0135] In one or more examples, expressions representing the OBSS
PD level are reproduced below:
OBSS_PD level = max { OBSS_PD min min { OBSS_PD max OBSS_PD min + (
TX_PWR ref - TX_PWR ) + M Opt 1 ) OBSS_PD level = max { OBSS_PD min
min { OBSS_PD max OBSS_PD min + ( TX PWR ref - TX PWR + M ) Opt 2 )
##EQU00001##
where TX_PWR.sub.ref is the reference power level, TX_PWR is the
transmission power in dBm for an HE STA, OBSS_PD.sub.min is the
minimum received sensitivity level, OBSS_PD.sub.max is the maximum
received sensitivity level. In one or more implementations, M is 0
when the received HE PPDU format is one of HE SU PPDU, HE MU PPDU
and HE trigger-based PPDU, or M is a first value when HE PPDU
format is the HE extended range SU PPDU format.
[0136] In one or more implementations, the first value (as M) is a
packet type dependent variable. In some implementations, the first
value is a positive integer when all HE PPDU formats necessitate
equal protection involving an SR transmission. In one or more
implementations, the first value can be a negative integer when the
HE extended range PPDU format needs protection from signal
interference by allowing SR transmissions. In one or more
implementations, the first value can be determined by an associated
AP. In one or more implementations, the first value can be changed
by AP node using a broadcasting frame. In one or more
implementations, the first value can be a fixed value.
[0137] In one or more implementations, the first value can be a
non-zero value when the packet type of the received frame
corresponds to a third type of frame format having a negligible (or
small) link margin available between a transmitter and a receiver,
thus causing an otherwise successful frame reception to be
susceptible to even a marginal amount of additional interference
from spatial reuse. The third type of the packet may be the HE
extended range SU PPDU. In one or more implementations, the third
type of the packet is a PPDU whose modulation and coding scheme
(MCS) level is with a low rate/rank.
[0138] If the transmit bandwidth differs from 20 MHz, both
OBSS_PDmax and OBSS_PDmin can be adjusted based on the following
expressions:
OBSS_PD max = OBSS_PD max ( 20 MHz ) + 10 log ( Bandwidth 20 MHz )
##EQU00002## OBSS PD min = OBSS PD min ( 20 MHz ) + 10 log (
Bandwidth 20 MHz ) ##EQU00002.2##
[0139] In one or more implementations (which may be referred to as
"E14" simply for convenience), a method of assessing a wireless
medium from a WLAN device when the WLAN device identifies a start
of a first frame is disclosed. The method may include measuring
received signal strength of a first part of the first frame;
identifying a BSS of the first frame; estimating received signal
strength of a second part of the first frame; and assessing the
wireless medium as IDLE if (1) the BSS of the first frame is
different from the BSS of the WLAN device and (2) the estimated
signal strength of the second part is lower than a first threshold
value.
[0140] In one or more implementations (e.g., E14 or other
implementations), the first part is a L-LTF field. In one or more
implementations (e.g., E14 or other implementations), the first
part is a L-STF field. In one or more implementations (e.g., E14 or
other implementations), the first part is HE-LTF field.
[0141] In one or more implementations (which may be referred to as
"E15" simply for convenience, and which may be, for example,
related to E14 or other implementations), the transmission power of
the first part is a predetermined level higher than that of the
second part of the first frame if the first frame is an HE PPDU
using an extended range preamble. In one or more implementations
(e.g., E15 or other implementations), the predetermined level is 3
dB. In one or more implementations (e.g., E15 or other
implementations), the estimated received signal strength of the
second part of the first frame is the predetermined level lower
than the measured received signal strength of the first part of the
first frame.
[0142] Assuming HE extended range SU PPDU is sent in case there is
not much of a link margin available between AP and STAs, this PPDU
can be more vulnerable to interference. This type of PPDU should be
protected from SR transmission from OBSS. In one or more
implementations (e.g., E15 or other implementations), the estimated
received signal strength of the second part of the first frame is a
second predetermined level higher than the measured received signal
strength of the first part of the first frame to allow that HE
extended range SU PPDU can be protected more than other HE PPDUs.
In one or more implementations (e.g., E14 or other
implementations), a first threshold value is adjusted with a second
predetermined level to allow that HE extended range SU PPDU to
receive more protection than other HE PPDUs. In one or more
implementations (e.g., E14 or other implementations), the second
part of the first frame comprises one or more of L-SIG, RL-SIG, or
HE-SIG-A field of the first frame. In one or more implementations
(e.g., E14 or other implementations), the second part of the first
frame is the first frame outside of the first part. Considering HE
extended range SU PPDU needs less interference from OBSSs to
support long range, SR mechanism may not be allowed.
[0143] In one or more implementations (which may be referred to as
"E16" simply for convenience), a method for early detection
procedure, where when the WLAN device receives the PPDU, the WLAN
device determines whether SR mechanism is allowed is disclosed. The
method may include detecting a PPDU format. If the detected PPDU
format is a first type of PPDU format, SR mechanism is not allowed
and the medium condition indicates BUSY. If the detected PPDU
format is a second type of PPDU format, the STA identifies a first
value of the PPDU frame which indicates whether SR mechanism is not
allowed or not. If the first value is set to a first state, SR
mechanism is not allowed and the STA maintains the medium condition
as BUSY until the duration of the detected PPDU.
[0144] Otherwise, the SR mechanism is allowed as follows. If the
first information matches with the STA's own BSSID, the STA
maintains the medium condition as BUSY until the duration of the
detected PPDU. If the first information does not match with the
STA's own BSSID and received signal level is greater than a first
threshold level, the STA maintains the medium condition as BUSY
until the duration of the detected PPDU. If the first information
does not match with the STA's own BSSID and received signal level
is lower than a first threshold level, the STA switch the medium
condition as IDLE. In one or more implementations (e.g., E16 or
other implementations), the first type of PPDU format can be HE
extended range SU PPDU.
[0145] In one or more implementations (e.g., E16 or other
implementations), if both condition 1) L-SIG Length set as mod3=2
and 2) quadrature binary phase-shift keying (QBPSK) on HE-SIG-A2
are met, the detected PPDU format is considered as HE extended
range SU PPDU. In other words, when dividing a value of the length
field of the L-SIG field of a frame by three (3) produces a
remainder of two (2) and a second OFDM symbol of the HE-SIG-A field
of the frame indicates QBPSK modulation, the frame is a HE extended
range SU PPDU format. In one or more implementations (e.g., E16 or
other implementations), the second type of PPDU format can be HE SU
PPDU, HE MU PPDU and HE trigger-based PPDU. In one or more
implementations (e.g., E16 or other implementations), if L-SIG
Length set as mod3=1 is met, the detected PPDU format is considered
as HE SU PPDU. In one or more implementations (e.g., E16 or other
implementations), if both condition 1) L-SIG Length set as mod3=2
and 2) binary phase shift keying (BPSK) on HE-SIG-A2 are met, the
detected PPDU format is considered as HE MU PPDU. In one or more
implementations (e.g., E16 or other implementations), the first
state of the first value of the PPDU frame can be an SR-not-allowed
indication. In one or more implementations (e.g., E16 or other
implementations), the SR-not-allowed indication can be in HE-SIG-A
of the received PPDU. In one or more implementations (e.g., E16 or
other implementations), the STA identifies the first type of PPDU
format, a control field containing the first value can be used for
other purposes.
[0146] In one or more implementations (e.g., E16 or other
implementations), SR mechanism comprising two NAVs is allowed as
follows. If the first information matches with the STA's own BSSID,
it sets/updates Intra-BSS NAV when the received Duration in the
intra-BSS PPDU is greater than the STA's current Intra-BSS NAV
value; otherwise, the STA regards the PPDU an inter-BSS PPDU. If
the PPDU is the inter-BSS PPDU and received signal level is greater
than a first threshold level, the STA sets/updates regular NAV when
the received Duration in the inter-BSS PPDU is greater than the
STA's current regular NAV value. In one or more implementations
(e.g., E16 or other implementations), the first threshold level can
be OBSS PD level. In one or more implementations (e.g., E16 or
other implementations), the first information can be any
information within the frame (e.g., color) which has information
related to (at least part of) BSSID.
[0147] In one or more implementations (e.g., E16, a variation of
E16, or other implementations), when transmitting a PPDU frame, the
type of the PPDU format is determined. If the determined type of
the PPDU frame is a first type of PPDU format, a WLAN device set a
first value with a first state in the first type of PPDU format.
Otherwise, the WLAN device set the first value with a second state
in the second type of the PPDU format. In one or more
implementations (e.g., E16, a variation of E16, or other
implementations), the first type of PPDU format can be HE extended
range SU PPDU. In one or more implementations (e.g., E16, a
variation of E16, or other implementations), the first state of
first value of the PPDU frame can be an SR-not-allowed indication.
In one or more implementations (e.g., E16, a variation of E16, or
other implementations), the SR-not-allowed indication can be in
HE-SIG-A of the received PPDU.
[0148] FIGS. 19A and 19B illustrate an example of detecting an
overlapping basic service set (OBSS) frame for spatial reuse. In
one or more implementations, early detection of a frame (e.g., HE
frame, PPDU, HE extended range SU PPDU) for spatial reuse is based
on a received power measured from the frame and a spatial reuse
parameter associated with an OBSS STA when a station (e.g., STA3)
considers a CCA-OA based procedure for initiating an SR
transmission.
[0149] In this example, STA2 (e.g., AP) transmits a trigger frame
(e.g., over a downlink transmission) to solicit a response from
STA1. STA1 transmits an UL trigger-based frame (e.g., UL MU PPDU)
in response to the trigger frame received from STA2. Meanwhile,
STA3 receives the trigger frame and the UL trigger-based frame
respectively from STA2 and STA1 as OBSS frames. STA3 may determine
whether the frames from STA1 and STA2 are inter-BSS (or OBSS)
frames based on color information or MAC address information. In
assessing whether STA3 can initiate an SR transmission, STA3
determines whether the SR transmission causes any severe
interference to STA2 when STA2 receives the UL trigger-based frame.
In one or more implementations, STA3 uses two values 1)
RSSI.sub.STA2@STA3 and 2) spatial reuse parameter (SRP) to adjust a
transmit power at STA3. These values facilitate STA3 for satisfying
SR conditions that may avoid signal interference at STA2.
[0150] When STA3 receives the trigger frame, STA3 measures a
received power (e.g., RSSI.sub.STA2@STA3) of the received trigger
frame. RSSI.sub.STA2@STA3 is a received power of the trigger frame
of STA2 measured at STA3 (e.g., a received power based on a legacy
preamble of the trigger frame of STA2 measured at STA3).
[0151] STA3 receives the SRP in the HE-SIG-A field of the UL
trigger-based frame. The SRP from the UL trigger-based frame may
correspond to an SRP in the HE-SIG-A field of the trigger frame. In
one example, STA1 copies and pastes the SRP in the HE-SIG-A field
of the trigger frame into the SRP in the HE-SIG-A field of the UL
trigger-based frame. In one or more implementations, the SRP is a
function of a transmit power at STA2 (e.g., TXPWR.sub.STA2) plus an
acceptable receiver interference level at STA2. STA3 may initiate
an SR transmission associated with STA3 based on the SRP and the
measured received power. For example, STA3 may initiate an SR
transmission when the estimated transmit power at STA3 is less than
a difference between the SRP and the measured received power at
STA3 (e.g., TX Power.sub.STA3<SRP-RSSI.sub.STA2@STA3, where
RSSI.sub.STA2@STA3 represents the measured received power in this
equation).
[0152] In the examples and implementations illustrated below (e.g.,
examples referring to FIG. 20A, 20B, 20C, 21D, 23A, or 23B below),
unless specifically stated otherwise, each of a downlink frame and
an uplink frame may be simply referred to as a frame.
Alternatively, the downlink frame may be referred to as a first
frame, and the uplink frame may be referred to as a second frame,
and vice versa. Each of a downlink transmission and an uplink
transmission may be simply referred to as a transmission.
Alternatively, the downlink transmission may be referred to as a
first transmission, and the uplink transmission may be referred to
as a second transmission, and vice versa.
[0153] FIGS. 20A and 20B illustrate an example of detecting an
overlapping basic service set (OBSS) frame for spatial reuse. In
FIGS. 20A and 20B, STA3 receives a first frame and a second frame
identified as OBSS frames, where the second frame is not
necessarily in response to the first frame. In one or more
implementations, one or more of the first frame and the second
frame has an HE SU PPDU format (e.g., FIG. 7A), an HE extended
range SU PPDU (e.g., FIG. 7C) or an HE MU PPDU format (e.g., FIG.
7B).
[0154] In this example, STA2 (e.g., AP) transmits a downlink frame
(e.g., Frame 1) over a downlink transmission to solicit a response
from STA1. STA1 transmits an uplink frame (e.g., Frame 2) in an
uplink transmission based on the downlink frame. In one or more
implementations, the uplink frame from STA1 is not in response to
the downlink frame from STA2 such that one or more frames may be
transmitted between the downlink frame (e.g., Frame 1) and the
uplink frame (e.g., Frame 2). Meanwhile, STA3 receives the downlink
frame and the uplink frame respectively from STA2 and STA1 as OBSS
frames. STA3 may determine whether the frames from STA1 and STA2
are inter-BSS (or OBSS) frames based on color information or MAC
address information. In assessing whether STA3 can initiate an SR
transmission, STA3 determines whether the SR transmission causes
any severe interference to STA2 when STA2 receives the uplink
frame. In one or more implementations, STA3 uses two values 1)
RSSI.sub.STA2@STA3 and 2) SRP to adjust a transmit power at STA3.
These values facilitate STA3 for satisfying SR conditions that may
avoid signal interference at STA2.
[0155] When STA3 receives the downlink frame, STA3 measures a
received power based on the legacy preamble of the received
downlink frame (e.g., RSSI.sub.STA2@STA3). RSSI.sub.STA2@STA3 is a
received power based on a legacy preamble of the downlink frame of
STA2 measured at STA3. STA3 may receive the SRP in the HE-SIG-A
field of the uplink frame. In one or more implementations, the SRP
is a function of a transmit power at STA1 (e.g., TXPWR.sub.STA1), a
received power based on a legacy preamble of the received downlink
frame of STA2 measured at STA1 (e.g. RSSI.sub.STA2@STA1), and a
signal-to-noise ratio (SNR) margin. For example, the SRP is TX
PWR.sub.STA1 plus RSSI.sub.STA2@STA1 minus SNR margin (i.e., SRP=TX
PWR.sub.STA1+RSSI.sub.STA2@STA1-SNR margin). In one or more
implementations, the SNR margin refers to the required SNR margin
as a function of MCS. In one or more implementations, when STA1
receives the downlink frame (e.g., Frame 1), STA1 measures the
received power based on the legacy preamble of the downlink frame
from STA2 (e.g., RSSI.sub.STA2@STA1). STA3 may initiate an SR
transmission associated with STA3 based on the SRP and the measured
received power at STA3 (e.g., RSSI.sub.STA2@STA3). For example,
STA3 may initiate an SR transmission when the estimated transmit
power at STA3 is less than a difference between the SRP and the
measured received power at STA3 (e.g., RSSI.sub.STA2@STA3). In
other words, an SR transmission is initiated when TX
Power.sub.STA3<SRP-RSSI.sub.STA2@STA3, where RSSI.sub.STA2@STA3
represents the received power based on a legacy preamble of the
downlink frame of STA2 measured at STA3).
[0156] In one or more implementations (which may be referred to as
"E20" simply for convenience and in connection with, for example,
FIGS. 19A and 19B), early detection of a frame (e.g., HE frame,
PPDU, HE extended range SU PPDU) for spatial reuse is based on a
received power measured based on a legacy preamble portion of
(e.g., L-STF or L-LTF) the frame and a spatial reuse parameter
associated with an OBSS STA when a station (e.g., STA3) considers a
CCA-OA based procedure for initiating an SR transmission.
[0157] In this example, STA2 (e.g., AP) transmits a trigger frame
(e.g., over a downlink transmission) to solicit a response from
STA1. STA1 transmits an UL trigger-based frame (e.g., UL MU PPDU)
in response to the trigger frame received from STA2. Meanwhile,
STA3 receives the trigger frame and the UL trigger-based frame
respectively from STA2 and STA1 as OBSS frames. STA3 may determine
whether the frames from STA1 and STA2 are inter-BSS (or OBSS)
frames based on color information or MAC address information. In
assessing whether STA3 can initiate an SR transmission, STA3
determines whether the SR transmission causes any severe
interference to STA2 when STA2 receives the UL trigger-based frame.
In one or more implementations, STA3 uses two values 1)
RSSI.sub.STA2@STA3 and 2) spatial reuse parameter (SRP) to adjust a
transmit power at STA3. These values facilitate STA3 for satisfying
SR conditions that may avoid signal interference at STA2.
[0158] When STA3 receives the trigger frame, STA3 measures a
received power based on the legacy preamble of the received trigger
frame (e.g., RSSI.sub.STA2@STA3). RSSI.sub.STA2@STA3 is a received
power based on a legacy preamble of the received trigger frame of
STA2 measured at STA3. STA3 may determine whether the received
trigger frame is an HE extended range SU PPDU, where power of the
L-STF/L-LTF symbols is boosted by a predetermined value (e.g., 3
dB). When the trigger frame is an HE extended range SU PPDU, STA3
adjusts the received power (RSSI.sub.STA2@STA3) measured based on
the legacy preamble by decreasing the received power by the
predetermined value to compensate for a power boost factor.
[0159] STA3 may receive the SRP in the HE-SIG-A field of the UL
trigger-based frame. The SRP from the UL trigger-based frame may
correspond to an SRP in the HE-SIG-A field of the trigger frame. In
one example, STA1 copies and pastes the SRP in the HE-SIG-A field
of the trigger frame into the SRP in the HE-SIG-A field of the UL
trigger-based frame. In one or more implementations, the SRP is a
function of a transmit power at STA2 (e.g., TXPWR.sub.STA2) plus an
acceptable receiver interference level at STA2. STA3 may initiate
an SR transmission associated with STA3 based on the SRP and the
adjusted received power (e.g., adjusted RSSI.sub.STA2@STA3). For
example, STA3 may initiate an SR transmission when the estimated
transmit power at STA3 is less than a difference between the SRP
and the adjusted received power at STA3 (e.g., TX
Power.sub.STA3<SRP-adjusted RSSI.sub.STA2@STA3).
[0160] In one or more implementations (which may be referred to as
"E21" simply for convenience and in connection with, for example,
FIGS. 20A and 20B), early detection of a frame (e.g., HE frame,
PPDU, HE extended range SU PPDU) for spatial reuse is based on a
received power measured based on a legacy preamble portion of
(e.g., L-STF or L-LTF) the frame and a spatial reuse parameter
associated with an OBSS STA when a station (e.g., STA3) considers a
CCA-OA based procedure for initiating an SR transmission.
[0161] In this example, STA2 (e.g., AP) transmits a downlink frame
(e.g., Frame 1) over a downlink transmission to solicit a response
from STA1. STA1 transmits an uplink frame (e.g., Frame 2) in an
uplink transmission based on the downlink frame. In one or more
implementations, the uplink frame from STA1 is not in response to
the downlink frame from STA2 such that one or more frames may be
transmitted between the downlink frame (e.g., Frame 1) and the
uplink frame (e.g., Frame 2). Meanwhile, STA3 receives the downlink
frame and the uplink frame respectively from STA2 and STA1 as OBSS
frames. STA3 may determine whether the frames from STA1 and STA2
are inter-BSS (or OBSS) frames based on color information or MAC
address information. In assessing whether STA3 can initiate an SR
transmission, STA3 determines whether the SR transmission causes
any severe interference to STA2 when STA2 receives the uplink
frame. In one or more implementations, STA3 uses two values 1)
RSSI.sub.STA2@STA3 and 2) SRP to adjust a transmit power at STA3.
These values facilitate STA3 for satisfying SR conditions that may
avoid signal interference at STA2.
[0162] When STA3 receives the downlink frame, STA3 measures a
received power based on the legacy preamble of the received
downlink frame (e.g., RSSI.sub.STA2@STA3). RSSI.sub.STA2@STA3 is a
received power based on a legacy preamble of the downlink frame of
STA2 measured at STA3. STA3 may determine whether the received
downlink frame is an HE extended range SU PPDU, where power of the
L-STF/L-LTF symbols is boosted by a predetermined value (e.g., 3
dB). When the downlink frame is an HE extended range SU PPDU, STA3
adjusts the received power (RSSI.sub.STA2@STA3) by decreasing the
received power by the predetermined value to compensate for a power
boost factor.
[0163] STA3 may receive the SRP in the HE-SIG-A field of the uplink
frame. In one or more implementations, the SRP is a function of a
transmit power at STA1 (e.g., TXPWR.sub.STA1), a received power
based on a legacy preamble of the received downlink frame of STA2
measured at STA1 (e.g. RSSI.sub.STA2@STA1), and a signal-to-noise
ratio (SNR) margin. For example, the SRP is TX PWR.sub.STA1 plus
RSSI.sub.STA2@STA1 minus SNR margin (i.e., SRP=TX
PWR.sub.STA1+RSSI.sub.STA2@STA1-SNR margin). In one or more
implementations, the SNR margin refers to the required SNR margin
as a function of MCS. In one or more implementations, when STA1
receives the downlink frame (e.g., Frame 1), STA1 measures the
received power based on the legacy preamble of the downlink frame
from STA2 (e.g., RSSI.sub.STA2@STA1). STA3 may initiate an SR
transmission associated with STA3 based on the SRP and the adjusted
received power (e.g., adjusted RSSI.sub.STA2@STA3). For example,
STA3 may initiate an SR transmission when the estimated transmit
power at STA3 is less than a difference between the SRP and the
adjusted received power (e.g., adjusted RSSI.sub.STA2@STA3). In
other words, an SR transmission is initiated TX
Power.sub.STA3<SRP-adjusted RSSI.sub.STA2@STA3.
[0164] In one or more implementations (which may be referred to as
"E22" simply for convenience and in connection with, for example,
FIGS. 20A and 20B), early detection of a frame (e.g., HE frame,
PPDU, HE extended range SU PPDU) for spatial reuse is based on a
received power measured based on a legacy preamble portion of
(e.g., L-STF or L-LTF) the frame and a spatial reuse parameter
associated with an OBSS STA when a station (e.g., STA3) considers a
CCA-OA based procedure for initiating an SR transmission.
[0165] In this example, STA2 (e.g., AP) transmits a downlink frame
(e.g., Frame 1) over a downlink transmission to solicit a response
from STA1. STA1 transmits an uplink frame (e.g., Frame 2) in an
uplink transmission based on the downlink frame. In one or more
implementations, the uplink frame from STA1 is not in response to
the downlink frame from STA2 such that one or more frames may be
transmitted between the downlink frame (e.g., Frame 1) and the
uplink frame (e.g., Frame 2).
[0166] When STA1 receives the downlink frame, STA1 measures a
received power based on the legacy preamble of the received
downlink frame (e.g., RSSI.sub.STA2@STA1). RSSI.sub.STA2@STA1 is a
received power based on a legacy preamble of the downlink frame of
STA2 measured at STA1. STA1 determines whether the received
downlink frame is an HE extended range SU PPDU, where power of the
L-STF/L-LTF symbols is boosted by a predetermined value (e.g., 3
dB). When the downlink frame is an HE extended range SU PPDU, STA1
adjusts the received power (e.g., RSSI.sub.STA2@STA1) by decreasing
the received power by the predetermined value to compensate for a
power boost factor. In this respect, STA1 can determine the SRP
since the SRP may be a function of a transmit power at STA1 (e.g.,
TXPWR.sub.STA1) plus the adjusted received power at STA1 based on
the downlink frame from STA2 (e.g., adjusted RSSI.sub.STA2@STA1),
minus a SNR margin. That is: SRP=TX PWR.sub.STA1+adjusted
RSSI.sub.STA2@STA1-SNR margin. The SNR margin may refer to the
required SNR margin as a function of MCS. The determined SRP may be
placed into the uplink frame by STA1.
[0167] Meanwhile, STA3 receives the downlink frame and the uplink
frame respectively from STA2 and STA1 as OBSS frames. STA3 may
determine whether the frames from STA1 and STA2 are inter-BSS (or
OBSS) frames based on color information or MAC address information.
In assessing whether STA3 can initiate an SR transmission, STA3
determines whether the SR transmission causes any severe
interference to STA2 when STA2 receives the uplink frame. In one or
more implementations, STA3 uses two values 1) RSSI.sub.STA2@STA3
and 2) SRP to adjust a transmit power at STA3. These values
facilitate STA3 for satisfying SR conditions that may avoid signal
interference at STA2.
[0168] In one or more implementations (which may be referred to as
"E23" simply for convenience and in connection with, for example,
FIGS. 20A and 20B), early detection of a frame (e.g., HE frame,
PPDU, HE extended range SU PPDU) for spatial reuse is based on a
received power measured based on a legacy preamble portion of
(e.g., L-STF or L-LTF) the frame and a spatial reuse parameter
associated with an OBSS STA when a station (e.g., STA3) considers a
CCA-OA based procedure for initiating an SR transmission.
[0169] In this example, STA2 (e.g., AP) transmits a downlink frame
(e.g., Frame 1) over a downlink transmission to solicit a response
from STA1. STA1 transmits an uplink frame (e.g., Frame 2) in an
uplink transmission based on the downlink frame. In one or more
implementations, the uplink frame from STA1 is not in response to
the downlink frame from STA2 such that one or more frames may be
transmitted between the downlink frame (e.g., Frame 1) and the
uplink frame (e.g., Frame 2).
[0170] When STA1 receives the downlink frame, STA1 measures a
received power based on the legacy preamble of the received
downlink frame (e.g., RSSI.sub.STA2@STA1). RSSI.sub.STA2@STA1 is a
received power based on a legacy preamble of the downlink frame of
STA2 measured at STA1. STA1 determines whether the received
downlink frame is an HE extended range SU PPDU, where power of the
L-STF/L-LTF symbols is boosted by a predetermined value (e.g., 3
dB). When the downlink frame is an HE extended range SU PPDU, STA1
adjusts the received power (e.g., RSSI.sub.STA2@STA1) by decreasing
the received power by the predetermined value to compensate for a
power boost factor. In this respect, STA1 can determine the SRP
since the SRP may be a function of a transmit power at STA1 (e.g.,
TXPWR.sub.STA1) plus the adjusted received power at STA1 based on
the downlink frame from STA2 (e.g., adjusted RSSI.sub.STA2@STA1),
minus a SNR margin in some embodiments. That is: SRP=TX
PWR.sub.STA1+adjusted RSSI.sub.STA2@STA1-SNR margin. The SNR margin
may refer to the required SNR margin as a function of MCS. The
determined SRP may be placed into the uplink frame by STA1.
[0171] Meanwhile, STA3 receives the downlink frame and the uplink
frame respectively from STA2 and STA1 as OBSS frames. STA3 may
determine whether the frames from STA1 and STA2 are inter-BSS (or
OBSS) frames based on color information or MAC address information.
In assessing whether STA3 can initiate an SR transmission, STA3
determines whether the SR transmission causes any severe
interference to STA2 when STA2 receives the uplink frame. In one or
more implementations, STA3 uses two values 1) RSSI.sub.STA2@STA3
and 2) SRP to adjust a transmit power at STA3. These values
facilitate STA3 for satisfying SR conditions that may avoid signal
interference at STA2.
[0172] When STA3 receives the downlink frame, STA3 measures a
received power based on the legacy preamble of the received
downlink frame (e.g., RSSI.sub.STA2@STA3). RSSI.sub.STA2@STA3 is a
received power based on a legacy preamble of the downlink frame of
STA2 measured at STA3. STA3 may determine whether the received
downlink frame is an HE extended range SU PPDU, where power of the
L-STF/L-LTF symbols is boosted by a predetermined value (e.g., 3
dB). When the downlink frame is an HE extended range SU PPDU, STA3
adjusts the received power (e.g., RSSI.sub.STA2@STA3) by decreasing
the received power by the predetermined value to compensate for a
power boost factor.
[0173] STA3 may receive the SRP in the HE-SIG-A field of the uplink
frame. STA3 may initiate an SR transmission associated with STA3
based on the SRP and the adjusted received power (e.g., adjusted
RSSI.sub.STA2@STA3). For example, STA3 may initiate an SR
transmission when the estimated transmit power at STA3 is less than
a difference between the SRP and the adjusted received power (e.g.,
adjusted RSSI.sub.STA2@STA3). In other words, an SR transmission is
initiated when TX Power.sub.STA3<SRP-adjusted
RSSI.sub.STA2@STA3.
[0174] In one or more implementations (which may be referred to as
"E24" simply for convenience and in connection with, for example,
FIGS. 20A and 20B), early detection of a frame (e.g., HE frame,
PPDU, HE extended range SU PPDU) for spatial reuse is based on a
received power measured based on a legacy preamble portion of
(e.g., L-STF or L-LTF) the frame and a spatial reuse parameter
associated with an OBSS STA when a station (e.g., STA3) considers a
CCA-OA based procedure for initiating an SR transmission.
[0175] When STA2 receives a frame (e.g., Frame 2), STA2 measures a
received power based on the legacy preamble of the received frame
(e.g., RSSI.sub.STA1@STA2). STA2 may determine whether the received
frame is an HE extended range SU PPDU, where power of the
L-STF/L-LTF symbols is boosted by a predetermined value (e.g., K
dB, which may be 3 dB). When the frame is an HE extended range SU
PPDU, STA2 adjusts the received power (e.g., RSSI.sub.STA1@STA2) by
decreasing the received power by the predetermined value.
[0176] Similarly, when STA3 receives a frame, STA3 measures a
received power based on a legacy preamble of the received frame
(e.g., RSSI.sub.STA2@STA3). STA3 may determine whether the received
frame is an HE extended range SU PPDU, where power of the
L-STF/L-LTF symbols is boosted by a predetermined value (e.g., K
dB, which may be 3 dB). When the frame is an HE extended range SU
PPDU, STA3 adjusts the received power (e.g., RSSI.sub.STA2@STA3) by
decreasing the received power by the predetermined value.
[0177] Considering the SR conditions, while a received power (e.g.,
RSSI) is measured based on the legacy preamble of a frame with an
HE PPDU format, there is no rule on a legacy PPDU with a VHT PPDU
format, in which the legacy PPDU is identified as an OBSS frame (or
inter-BSS frame) based on a MAC address in a PSDU.
[0178] In one or more implementations, the PHY includes the most
recently measured RSSI value in the PHY-RXSTART.indication (e.g.,
RXVECTOR) primitive issued to the MAC when it starts decoding the
PSDU. After identifying the frame as an OBSS frame, where the MAC
address of the frame does not match to its BSS identifier (BSSID),
the RSSI is measured based on a non-legacy preamble (e.g., VHT-LTF
symbols). The measured RSSI based on the non-legacy preamble is
likely to be different from the measured RSSI based on the legacy
preamble (e.g., L-LTF).
[0179] In one or more implementations (which may be referred to as
"E25" simply for convenience and in connection with, for example,
FIGS. 19A and 19B or FIGS. 20A and 20B), early detection of a frame
(e.g., VHT frame, HE frame, PPDU, HE extended range SU PPDU) for
spatial reuse is based on a received power measured when a station
(e.g., STA3) considers initiating an SR transmission.
[0180] When a station (e.g., STA3) receives a frame with an HE PPDU
format, which is identified as an OBSS frame based on color
information (e.g., color bits) in the HE-SIG-A field, the received
power (e.g., RSSI) that is measured based on the legacy preamble is
issued to the MAC for processing.
[0181] Similarly when a station (e.g., STA3) receives a frame with
a legacy PPDU format, which is identified as an OBSS frame based on
a MAC address in the PSDU, the received power (e.g., RSSI) that is
measured based on the legacy preamble is issued to the MAC for
processing. In one or more implementations, the received power that
is measured based on the non-legacy preamble (e.g., HT-LTFs,
VHT-LTFs) is filtered out and not issued to the MAC for
processing.
[0182] FIGS. 21A through 21D illustrate examples of early detection
of an overlapping basic service set (OBSS) frame when beamforming
is applied for spatial reuse. In FIG. 21A, a transmitter (e.g.,
STA1) sends an uplink frame (e.g., UL trigger-based PPDU) to a
receiver (e.g., STA2). Under one or more SR transmission rules in
the IEEE 802.11ax specification, when an SR STA initiator (e.g.,
STA3) receives an inter-BSS PPDU (e.g., OBSS frame), STA3 measures
the received power (e.g., RSSI) based on the legacy portion of the
inter-BSS PPDU to consider the condition that allows an SR
transmission to be initiated during a given time duration.
[0183] In meeting the one or more SR conditions, the SR STA
initiator (e.g., STA3) determines to transmit an SR PPDU that is
beamformed to a direction targeting an SR STA responder (e.g.,
STA4). As illustrated in FIGS. 20A and 20C, the beam direction is
formed in the direction of STA2. In this respect, if STA4 happens
to be located near the receiver (e.g., STA2), the beamformed SR
PPDU may give off an unexpected interference at STA2 when STA2
receives the beamformed SR PPDU, because STA2 did not take into
consideration the beamforming effect from the SR STA initiator
(e.g., STA3). Moreover, it may be difficult for the station (e.g.,
STA3) to estimate the channel condition to the receiver (e.g.,
STA2) in order for the station (e.g., STA2) to avoid additional
interference due to beamforming. In this respect, it may be
difficult for STA3 to estimate the actual beamforming gain toward
STA2.
[0184] To address this beamforming effect, determining a
transmission power from an SR STA initiator is described in the
present disclosure. In one or more implementations, when an SR STA
initiator (e.g., STA3) intends to transmit a set of frames to a
target receiver (e.g., STA4) utilizing SR transmission procedures,
the SR STA initiator may consider the estimated beamforming gain
when the SR STA initiator calculates the allowed transmission power
during the SR transmission. For example, the estimated beamforming
gain is the estimated beamforming gain toward the target
receiver.
[0185] In one or more implementations (which may be referred to as
"E25a" simply for convenience and in connection with, for example,
FIGS. 21A and 21B), early detection of a frame (e.g., HE frame,
PPDU, HE extended range SU PPDU) for spatial reuse is based on a
received power measured based on a legacy preamble portion (e.g.,
L-STF or L-LTF) of the frame and a spatial reuse parameter
associated with an OBSS STA when a station (e.g., STA3) considers a
CCA-OA based procedure for initiating an SR transmission when
beamforming is applied.
[0186] In this example, STA2 (e.g., AP) transmits a trigger frame
(e.g., over a downlink transmission) to solicit a response from
STA1. STA1 transmits an UL trigger-based frame (e.g., UL MU PPDU)
in response to the trigger frame received from STA2. Meanwhile,
STA3 receives the trigger frame and the UL trigger-based frame
respectively from STA2 and STA1 as OBSS frames. STA3 may determine
whether the frames from STA1 and STA2 are inter-BSS (or OBSS)
frames based on color information or MAC address information. In
assessing whether STA3 can initiate an SR transmission, STA3
determines whether the SR transmission causes any severe
interference to STA2 when STA2 receives the UL trigger-based frame.
In one or more implementations, STA3 uses three values 1)
RSSI.sub.STA2@STA3, 2) SRP to adjust a transmit power at STA3, and
3) .alpha. corresponding to a value of beamforming gain to adjust a
transmit power at STA3. These values facilitate STA3 for satisfying
SR conditions that may avoid signal interference at STA2.
[0187] When STA3 receives the trigger frame, STA3 measures a
received power based on the legacy preamble of the received trigger
frame (e.g., RSSI.sub.STA2@STA3). RSSI.sub.STA2@STA3 is a received
power based on a legacy preamble of the trigger frame of STA2
measured at STA3. STA3 may determine whether the received trigger
frame is an HE extended range SU PPDU, where power of the
L-STF/L-LTF symbols is boosted by a predetermined value (e.g., 3
dB). When the trigger frame is an HE extended range SU PPDU, STA3
adjusts the received power (e.g., RSSI.sub.STA2@STA3) by decreasing
the received power by the predetermined value to compensate for a
power boost factor.
[0188] STA3 may receive the SRP in the HE-SIG-A field of the UL
trigger-based frame. The SRP from the UL trigger-based frame may
correspond to an SRP in the HE-SIG-A field of the trigger frame. In
one example, STA1 copies and pastes the SRP in the HE-SIG-A field
of the trigger frame into the SRP in the HE-SIG-A field of the UL
trigger-based frame. In one or more implementations, the SRP is a
function of a transmit power at STA2 (e.g., TXPWR.sub.STA2) plus an
acceptable receiver interference level at STA2. STA3 may initiate
an SR transmission associated with STA3 based on the SRP and the
adjusted received power (e.g., adjusted RSSI.sub.STA2@STA3). For
example, STA3 may initiate an SR transmission when the estimated
transmit power at STA3 is less than a difference between the SRP
and the sum of the adjusted received power at STA3 and the a value
(e.g., TX Power.sub.STA3<SRP-adjusted
RSSI.sub.STA2@STA3-.alpha., where .alpha. is set to a non-zero
value when the SR PPDU from STA3 is beamformed, where .alpha. is
set to a non-zero value that refers to the estimated beamforming
gain to the SR STA responder, and where .alpha. is set to a
non-zero value that refers to the estimated maximum beamforming
gain that the SR STA initiator can have during the SR
transmission).
[0189] In one or more implementations (which may be referred to as
"E21 a" simply for convenience and in connection with, for example,
FIGS. 20A and 20B), early detection of a frame (e.g., HE frame,
PPDU, HE extended range SU PPDU) for spatial reuse is based on a
received power measured based on a legacy preamble portion (e.g.,
L-STF or L-LTF) of the frame and a spatial reuse parameter
associated with an OBSS STA when a station (e.g., STA3) considers a
CCA-OA based procedure for initiating an SR transmission when
beamforming is applied.
[0190] In this example, STA2 (e.g., AP) transmits a downlink frame
(e.g., Frame 1) over a downlink transmission to solicit a response
from STA1. STA1 transmits an uplink frame (e.g., Frame 2) in an
uplink transmission based on the downlink frame. In one or more
implementations, the uplink frame from STA1 is not in response to
the downlink frame from STA2 such that one or more frames may be
transmitted between the downlink frame (e.g., Frame 1) and the
uplink frame (e.g., Frame 2). Meanwhile, STA3 receives the downlink
frame and the uplink frame respectively from STA2 and STA1 as OBSS
frames. STA3 may determine whether the frames from STA1 and STA2
are inter-BSS (or OBSS) frames based on color information or MAC
address information. In assessing whether STA3 can initiate an SR
transmission, STA3 determines whether the SR transmission causes
any severe interference to STA2 when STA2 receives the uplink
frame. In one or more implementations, STA3 uses three values as 1)
RSSI.sub.STA2@STA3, 2) SRP to adjust a transmit power at STA3, and
3) a corresponding to a value of beamforming gain to adjust a
transmit power at STA3. These values facilitate STA3 for satisfying
SR conditions that may avoid signal interference at STA2.
[0191] When STA3 receives the downlink frame, STA3 measures a
received power based on the legacy preamble of the received
downlink frame (e.g., RSSI.sub.STA2@STA3). RSSI.sub.STA2@STA3 is a
received power based on a legacy preamble of the downlink frame of
STA2 measured at STA3. STA3 may determine whether the received
downlink frame is an HE extended range SU PPDU, where power of the
L-STF/L-LTF symbols is boosted by a predetermined value (e.g., 3
dB). When the downlink frame is an HE extended range SU PPDU, STA3
adjusts the received power (e.g., RSSI.sub.STA2@STA3) by decreasing
the received power by the predetermined value to compensate for a
power boost factor.
[0192] STA3 may receive the SRP in the HE-SIG-A field of the uplink
frame. In one or more implementations, the SRP is a function of a
transmit power at STA1 (e.g., TXPWR.sub.STA1), a received power
based on a legacy preamble of the received downlink frame of STA2
measured at STA1 (e.g., RSSI.sub.STA2@STA1), and an SNR margin. For
example, the SRP is TX PWR.sub.STA1 plus RSSI.sub.STA2@STA1 minus
SNR margin (i.e., SRP=TX PWR.sub.STA1+RSSI.sub.STA2@STA1-SNR
margin). In one or more implementations, the SNR margin refers to
the required SNR margin as a function of MCS. In one or more
implementations, when STA1 receives the downlink frame (e.g., Frame
1), STA1 measures the received power measured based on the legacy
preamble of the downlink frame (e.g., RSSI.sub.STA2@STA1). STA3 may
initiate an SR transmission associated with STA3 based on the SRP,
the adjusted received power (e.g., adjusted RSSI.sub.STA2@STA3),
and the a value. For example, STA3 may initiate an SR transmission
when the estimated transmit power at STA3 is less than a difference
between the SRP and the sum of the adjusted received power and the
a value (e.g., TX Power.sub.STA3<SRP-adjusted
RSSI.sub.STA2@STA3-.alpha., where .alpha. is set to a non-zero
value when the SR PPDU from STA3 is beamformed, where .alpha. is
set to a non-zero value that refers to the estimated beamforming
gain to the SR STA responder, and where .alpha. is set to a
non-zero value that refers to the estimated maximum beamforming
gain that the SR STA initiator can have during the SR
transmission).
[0193] In one or more implementations (which may be referred to as
"E22a" simply for convenience and in connection with, for example,
FIGS. 20A and 20B), early detection of a frame (e.g., HE frame,
PPDU, HE extended range SU PPDU) for spatial reuse is based on a
received power measured based on a legacy preamble portion (e.g.,
L-STF or L-LTF) of the frame and a spatial reuse parameter
associated with an OBSS STA when a station (e.g., STA3) considers a
CCA-OA based procedure for initiating an SR transmission when
beamforming is applied.
[0194] In this example, STA2 (e.g., AP) transmits a downlink frame
(e.g., Frame 1) over a downlink transmission to solicit a response
from STA1. STA1 transmits an uplink frame (e.g., Frame 2) in an
uplink transmission based on the downlink frame. In one or more
implementations, the uplink frame from STA1 is not in response to
the downlink frame from STA2 such that one or more frames may be
transmitted between the downlink frame (e.g., Frame 1) and the
uplink frame (e.g., Frame 2).
[0195] When STA1 receives the downlink frame, STA1 measures a
received power based on the legacy preamble of the received
downlink frame (e.g., RSSI.sub.STA2@STA1). RSSI.sub.STA2@STA1 is a
received power based on a legacy preamble of the downlink frame of
STA2 measured at STA1. STA1 determines whether the received
downlink frame is an HE extended range SU PPDU, where power of the
L-STF/L-LTF symbols is boosted by a predetermined value (e.g., 3
dB). When the downlink frame is an HE extended range SU PPDU, STA1
adjusts the received power (e.g., RSSI.sub.STA2@STA1) by decreasing
the received power by the predetermined value to compensate for a
power boost factor. In this respect, STA1 can determine the SRP
since the SRP may be a function of a transmit power at STA1 (e.g.,
TXPWR.sub.STA1) plus the adjusted received power (e.g., adjusted
RSSI.sub.STA2@STA1), minus a SNR margin. That is: SRP=TX
PWR.sub.STA1+adjusted RSSI.sub.STA2@STA1-SNR margin. The SNR margin
may refer to the required SNR margin as a function of MCS. The
determined SRP may be added into the uplink frame by STA1.
[0196] Meanwhile, STA3 receives the downlink frame and the uplink
frame respectively from STA2 and STA1 as OBSS frames. STA3 may
determine whether the frames from STA1 and STA2 are inter-BSS (or
OBSS) frames based on color information or MAC address information.
In assessing whether STA3 can initiate an SR transmission, STA3
determines whether the SR transmission causes any severe
interference to STA2 when STA2 receives the uplink frame. In one or
more implementations, STA3 uses three values as 1)
RSSI.sub.STA2@STA3, 2) SRP to adjust a transmit power at STA3, and
3) .alpha. corresponding to a value of beamforming gain to adjust a
transmit power at STA3, where .alpha. is set to a non-zero value
when the SR PPDU from STA3 is beamformed, where .alpha. is set to a
non-zero value that refers to the estimated beamforming gain to the
SR STA responder, and where .alpha. is set to a non-zero value that
refers to the estimated maximum beamforming gain that the SR STA
initiator can have during the SR transmission. These values
facilitate STA3 for satisfying SR conditions that may avoid signal
interference at STA2.
[0197] In one or more implementations (which may be referred to as
"E23a" simply for convenience and in connection with, for example,
FIGS. 20A and 20B), early detection of a frame (e.g., HE frame,
PPDU, HE extended range SU PPDU) for spatial reuse is based on a
received power measured based on a legacy preamble portion (e.g.,
L-STF or L-LTF) of the frame and a spatial reuse parameter
associated with an OBSS STA when a station (e.g., STA3) considers a
CCA-OA based procedure for initiating an SR transmission when
beamforming is applied.
[0198] In this example, STA2 (e.g., AP) transmits a downlink frame
(e.g., Frame 1) over a downlink transmission to solicit a response
from STA1. STA1 transmits an uplink frame (e.g., Frame 2) in an
uplink transmission based on the downlink frame. In one or more
implementations, the uplink frame from STA1 is not in response to
the downlink frame from STA2 such that one or more frames may be
transmitted between the downlink frame (e.g., Frame 1) and the
uplink frame (e.g., Frame 2).
[0199] When STA1 receives the downlink frame, STA1 measures a
received power based on the legacy preamble of the received
downlink frame (e.g., RSSI.sub.STA2@STA1). RSSI.sub.STA2@STA1 is a
received power based on a legacy preamble of the downlink frame of
STA2 measured at STA1. STA1 determines whether the received
downlink frame is an HE extended range SU PPDU, where power of the
L-STF/L-LTF symbols is boosted by a predetermined value (e.g., 3
dB). When the downlink frame is an HE extended range SU PPDU, STA1
adjusts the received power (e.g., RSSI.sub.STA2@STA1) by decreasing
the received power by the predetermined value to compensate for a
power boost factor. In this respect, STA1 can determine the SRP
since the SRP may be a function of a transmit power at STA1 (e.g.,
TXPWR.sub.STA1) plus the adjusted received power at STA1 based on
the downlink frame from STA2 (e.g., adjusted RSSI.sub.STA2@STA1),
minus an SNR margin in some embodiments. The SNR margin may refer
to the required SNR margin as a function of MCS. The determined SRP
may be added into the uplink frame by STA1.
[0200] Meanwhile, STA3 receives the downlink frame and the uplink
frame respectively from STA2 and STA1 as OBSS frames. STA3 may
determine whether the frames from STA1 and STA2 are inter-BSS (or
OBSS) frames based on color information or MAC address information.
In assessing whether STA3 can initiate an SR transmission, STA3
determines whether the SR transmission causes any severe
interference to STA2 when STA2 receives the uplink frame. In one or
more implementations, STA3 uses three values as 1)
RSSI.sub.STA2@STA3, 2) SRP to adjust a transmit power at STA3, and
3) a corresponding to a value of beamforming gain to adjust a
transmit power at STA3. These values facilitate STA3 for satisfying
SR conditions that may avoid signal interference at STA2.
[0201] When STA3 receives the downlink frame, STA3 measures a
received power based on the legacy preamble of the received
downlink frame (e.g., RSSI.sub.STA2@STA3). RSSI.sub.STA2@STA3 is a
received power based on a legacy preamble of the downlink frame of
STA2 measured at STA3. STA3 may determine whether the received
downlink frame is an HE extended range SU PPDU, where power of the
L-STF/L-LTF symbols is boosted by a predetermined value (e.g., 3
dB). When the downlink frame is an HE extended range SU PPDU, STA3
adjusts the received power (e.g., RSSI.sub.STA2@STA3) by decreasing
the received power by the predetermined value to compensate for a
power boost factor.
[0202] STA3 may receive the SRP in the HE-SIG-A field of the uplink
frame. STA3 may initiate an SR transmission associated with STA3
based on the SRP, the adjusted received power (e.g., adjusted
RSSI.sub.STA2@STA3) and the a value. For example, STA3 may initiate
an SR transmission when the estimated transmit power at STA3 is
less than a difference between the SRP and the sum of adjusted
received power at STA3 and the a value (e.g., TX
Power.sub.STA3<SRP-adjusted RSSI.sub.STA2@STA3-.alpha., where
.alpha. is set to a non-zero value when the SR PPDU from STA3 is
beamformed, where .alpha. is set to a non-zero value that refers to
the estimated beamforming gain to the SR STA responder, and where
.alpha. is set to a non-zero value that refers to the estimated
maximum beamforming gain that the SR STA initiator can have during
the SR transmission).
[0203] FIGS. 22A and 22B illustrate an example of detecting an
overlapping basic service set (OBSS) frame for spatial reuse. In
this example, STA2 (e.g., AP) transmits a trigger frame (e.g.,
2201) over a downlink transmission to solicit a response from STA1.
STA1 transmits an UL trigger-based frame (e.g., UL MU PPDU 2202) in
response to the trigger frame received from STA2. Meanwhile, STA3
receives the trigger frame and the UL trigger-based frame
respectively from STA2 and STA1 as OBSS frames. STA3 may determine
whether the frames from STA1 and STA2 are inter-BSS (or OBSS)
frames based on color information or MAC address information. In
assessing whether STA3 can initiate an SR transmission (e.g.,
2204), STA3 determines whether the SR transmission causes any
severe interference to STA2 when STA2 receives the UL trigger-based
frame.
[0204] However, in dense circumstances, there may exist some cases
where an SR STA initiator (e.g., STA3) may receive one or more
other PPDU(s), which may be partially overlapped during a
DIFS/backoff procedure for an SRP-based SR transmission when the
medium condition associated with STA3 indicates an IDLE
channel.
[0205] In a given time duration during which an SR transmission is
allowed to be initiated (or has been initiated) by the SR STA
(e.g., STA3), one or more other frames may be received during this
time that cause STA3 to reconsider whether to suspend the SR
transmission. When the SR STA initiator (e.g., STA3) receives the
UL trigger-based PPDU frame (e.g., 2202), STA3 checks the contents
of the UL trigger-based PPDU and determines that the UL
trigger-based PPDU is an inter-frame. STA3 adjusts a transmit power
at STA3 to satisfy one or more SR conditions directed to avoiding
signal interference at STA2 (e.g.,
TXPower.sub.STA3<SRP-RSSI.sub.STA2@STA3). During a time that the
medium condition indicates an IDLE channel, the start of the
another PPDU (e.g., 2203) may be detected. In this respect, it may
be unclear how the SR STA initiator (e.g., STA3) behaves. STA3 may
initiate another iteration of an SRP-based SR transmission
procedure, which would require at least two HE PPDUs to be
detected. However, the newly-detected frame (e.g., 2203) may be a
legacy frame containing no SRP field, such that initiating another
round of the SRP-based SR transmission procedure may consume
resources unnecessarily. In some aspects, STA3 may consider an
OBSS-PD level based SR transmission, where the measured received
power is compared to a predetermined OBSS PD level. Since the
transmit power at STA3 is based on the SRP-based PPDU at the time
when the other PPDU was detected, the transmit power is likely to
be greater than the OBSS PD level, thus complicating the chances
for STA3 to be allowed to initiate the SR transmission.
[0206] FIGS. 23A and 23B illustrate an example of detecting an
overlapping basic service set (OBSS) frame for spatial reuse. The
same issues as those discussed in FIGS. 22A and 22B can be observed
in FIGS. 23A and 23B, involving a different type of SRP-based SR
transmission (e.g., E21).
[0207] FIG. 24 illustrates an example of detecting an inter-BSS
frame during a period for initiating a spatial reuse transmission.
In one or more implementations (which may be referred to as "E24"
simply for convenience and in connection with, for example, FIGS.
22A and 22B, and FIGS. 23A and 23B), when an SR STA initiator
(e.g., STA3) is in a DIFS/backoff procedure after satisfying one or
more SRP-based SR transmission conditions, the SR STA initiator may
behave as follows when STA3 receives a second frame (i.e., a frame
other than the frame sent by STA1 and the frame sent by STA2). For
example, a second frame may be a frame 2203 or a frame 2303.
[0208] If the SR STA initiator (e.g., STA3) meets any of the
following condition(s), then the SR STA initiator stops (or
suspends) the SR transmission procedure. In this respect, STA3
indicates that the medium condition is a BUSY channel (i.e., medium
condition transitions from an IDLE channel to a BUSY channel), and
SR STA initiator (e.g., STA3) stops the backoff countdown (e.g.,
decrementing backoff slots): [0209] the SR STA initiator detects
the start of a valid frame (e.g., the second frame, such as the
frame 2203 or 2303, is determined to be an OBSS frame or to
originate from another STA (e.g., not STA1 or STA2)); [0210] the
receive power is increased to be greater than a predetermined
threshold (e.g., the sum of the received power of the frame 2202
and the received power of the frame 2203 is greater than a
predetermined threshold; or the sum of the received power of the
frame 2302 and the received power of the frame 2303 is greater than
a predetermined threshold), where the predetermined threshold may
be set to an OBSS PD level; [0211] the increased receive power is
larger than a predetermined delta value (e.g., the power increase
due to the frame 2203 (or 2303) is larger than the predetermined
delta value); and/or [0212] the received power is increased (e.g.,
when the frame 2203 or 2303 is received at STA3) (i) before HE-STF
of the first HE inter-BSS frame (e.g., the frame 2202 or 2302) or
(ii) after HE-LTF of the first HE inter BSS frame, where each of
HE-STF and HE-LTF is a region where beamforming gain can be
applied.
[0213] In one or more implementations (e.g., E24 or other
implementations), if the SR STA initiator (e.g., STA3) determines
that the estimated packet detect CCA (or measured received power)
of the second frame (e.g., the frame 2203 or 2303) is less than the
OBSS PD level (e.g., as a condition of an OBSS PD based SR
transmission), then SR STA initiator (e.g., STA3) indicates that
the medium condition is IDLE, and SR STA initiator (e.g., STA3)
resumes (or starts) the backoff countdown process (e.g.,
decrementing backoff slot values to zero). The estimated packet
detect CCA (or received power) may be calculated with the first HE
inter-BSS frame (e.g., 2202, 2302) and the overlapped OBSS PD level
(e.g., a predetermined threshold). In one or more implementations
(e.g., E24 or other implementations), the SR STA initiator (e.g.,
STA3) follows an OBSS PD based SR transmission rule for SR
transmission, where the SR duration may be an SR duration set up
based on OA-CCA first, and/or where the SR duration may be a value
of a transmission opportunity (TXOP) duration field in the HE-SIG-A
field of the first HE inter-BSS frame.
[0214] It should be noted that like reference numerals may
designate like elements. These components with the same reference
numerals have certain characteristics that are the same, but as
different figures illustrate different examples, the same reference
numeral does not indicate that a component with the same reference
numeral has the exact same characteristics. While the same
reference numerals are used for certain components, examples of
differences with respect to a component are described throughout
this disclosure.
[0215] The embodiments provided herein have been described with
reference to a wireless LAN system; however, it should be
understood that these solutions are also applicable to other
network environments, such as cellular telecommunication networks,
wired networks, etc.
[0216] An embodiment of the present disclosure may be an article of
manufacture in which a non-transitory machine-readable medium (such
as microelectronic memory) has stored thereon instructions which
program one or more data processing components (generically
referred to here as a "processor" or "processing unit") to perform
the operations described herein. In other embodiments, some of
these operations may be performed by specific hardware components
that contain hardwired logic (e.g., dedicated digital filter blocks
and state machines). Those operations may alternatively be
performed by any combination of programmed data processing
components and fixed hardwired circuit components.
[0217] In some cases, an embodiment of the present disclosure may
be an apparatus (e.g., an AP STA, a non-AP STA, or another network
or computing device) that includes one or more hardware and
software logic structure for performing one or more of the
operations described herein. For example, as described above, the
apparatus may include a memory unit, which stores instructions that
may be executed by a hardware processor installed in the apparatus.
The apparatus may also include one or more other hardware or
software elements, including a network interface, a display device,
etc.
[0218] FIGS. 25A, 25B, and 25C illustrate flow charts of examples
of methods for facilitating wireless communication. For explanatory
and illustration purposes, the example processes 2510, 2520, and
2530 may be performed by the wireless communication devices 111-115
of FIG. 1 and their components such as a baseband processor 210, a
MAC processor 211, a MAC software processing unit 212, a MAC
hardware processing unit 213, a PHY processor 215, a transmitting
signal processing unit 280 and/or a receiving signal processing
unit 290; however, the example processes 2510, 2520, and 2530 are
not limited to the wireless communication devices 111-115 of FIG. 1
or their components, and the example processes 2510, 2520, 2530 may
be performed by some of the devices shown in FIG. 1, or other
devices or components. Further, for explanatory and illustration
purposes, the blocks of the example processes 2510, 2520, 2530 are
described herein as occurring in serial or linearly. However,
multiple blocks of the example processes 2510, 2520, 2530 may occur
in parallel. In addition, the blocks of the example processes 2510,
2520, 2530 need not be performed in the order shown and/or one or
more of the blocks/actions of the example processes 2510, 2520,
2530 need not be performed. Various examples of aspects of the
disclosure are described below as clauses for convenience. These
are provided as examples, and do not limit the subject technology.
As an example, some of the operations described below are
illustrated in FIGS. 25A, 25B, and 25C.
[0219] FIG. 25A illustrates a flow chart of the example process
2510. In step 2511, a wireless device (or station) processes a
frame received from a station. The frame is processed to decode a
HE-SIG-A field of the frame and to obtain color information from
the HE-SIG-A field. In step 2512, the wireless device determines
whether the frame is an inter-BSS frame associated with a second
wireless network based on the color information during a period of
time of which a medium condition associated with the wireless
device indicates a busy channel. If the frame is an inter-BSS frame
associated with the second wireless network, the process 2510
proceeds to step 2513. In step 2513, the wireless device determines
a first received power that is based on a legacy preamble portion
of the frame, where the legacy preamble portion is a first received
long training field of the frame. In step 2514, the wireless device
determines a second received power that is based on a non-legacy
preamble portion of the frame, where the non-legacy preamble
portion is a second received long training field of the frame. In
step 2515, the wireless device determines that the inter-BSS frame
is a HE extended range SU PPDU format when dividing a value of a
length field of a legacy signal (L-SIG) field of the frame by three
produces a remainder of two and a second symbol of the HE-SIG-A
field indicates QBPSK modulation. In step 2516, the wireless device
adjusts the first received power by an adjustment value based on
the inter-BSS frame being a HE extended range SU PPDU format. In
step 2517, the wireless device determines whether the adjusted
first received power is less than an OBSS PD level. If the adjusted
received power is determined to be equal to or greater than the
OBSS PD level, then process 2510 proceeds to step 2518. Otherwise,
process 2510 proceeds to step 2519. In step 2518, the wireless
device revises a NAV timer by setting the NAV timer based on the
adjusted first received power being equal to or greater than the
OBSS PD level. In step 2519, the wireless device initiates a
spatial reuse transmission based on the adjusted first received
power being less than the OBSS PD level.
[0220] FIG. 25B illustrates a flow chart of the example process
2520. In step 2521, a wireless device (or station) processes a
first frame and a second frame of a frame exchange between a first
station and a second station, in which the second frame is
responsive to the first frame of the frame exchange. The first
frame can be a trigger frame and the second frame can be an UL
trigger based frame. In step 2522, the wireless device determines
that one or more of the first frame and the second frame are
associated with a second wireless network, based on color
information in a HE-SIG-A field of the first frame and second frame
respectively, or based on a match between either transmit or
receive addresses in a MAC header of the first frame and second
frame respectively. In step 2523, the wireless devices obtains a
received power measured based on a portion of the first frame when
one or more of the first frame and the second frame are associated
with the second wireless network. In step 2524, the wireless device
determines that the frame is a HE extended range SU PPDU format. In
step 2525, the wireless device adjusts the received power by a
predetermined value in response to determining that the frame is a
HE extended range SU PPDU format. In step 2526, the wireless device
obtains a spatial reuse parameter associated with the first station
from the HE-SIG-A field of the second frame, in which the spatial
reuse parameter is based on a transmission power level at the first
station and an interference level at the first station. In step
2527, the wireless device initiates a spatial reuse transmission
when a transmission power level by the wireless device is less than
a difference between the spatial reuse parameter and the adjusted
received power.
[0221] FIG. 25C illustrates a flow chart of the example process
2530. In step 2531, a wireless device (or station) is processing a
frame received from a station. In step 2532, the wireless device is
determining that the frame is an inter-BSS frame associated with a
second wireless network. In step 2533, the wireless device is
determining that the frame is carried in a HE extended range SU
PPDU. In step 2534, the wireless device is obtaining a received
power measurement based on legacy preamble symbols of the frame. In
step 2535, the wireless device is decreasing the received power by
a predetermined value to compensate for a power boost factor when
the received power is compared to an OBSS PD level. In step 2536,
the wireless device is initiating a spatial reuse transmission
associated with the wireless device, based on the decreased
received power when the adjusted received power is less than the
OBSS PD level.
[0222] In one or more aspects, clauses regarding the present
disclosure are described below.
[0223] A method comprising one or more methods or operations
described herein.
[0224] An apparatus or a station comprising one or more memories
(e.g., 240, one or more internal, external or remote memories, or
one or more registers) and one or more processors (e.g., 210)
coupled to the one or more memories, the one or more processors
configured to cause the apparatus to perform one or more methods or
operations described herein.
[0225] An apparatus or a station comprising one or more memories
(e.g., 240, one or more internal, external or remote memories, or
one or more registers) and one or more processors (e.g., 210 or one
or more portions), wherein the one or more memories store
instructions that, when executed by the one or more processors,
cause the one or more processors to perform one or more methods or
operations described herein.
[0226] An apparatus or a station comprising means (e.g., 210)
adapted for performing one or more methods or operations described
herein.
[0227] A computer-readable storage medium (e.g., 240, one or more
internal, external or remote memories, or one or more registers)
comprising instructions stored therein, the instructions comprising
code for performing one or more methods or operations described
herein.
[0228] A computer-readable storage medium (e.g., 240, one or more
internal, external or remote memories, or one or more registers)
storing instructions that, when executed by one or more processors
(e.g., 210 or one or more portions), cause the one or more
processors to perform one or more methods or operations described
herein.
[0229] In one aspect, a method may be an operation, an instruction,
or a function and vice versa. In one aspect, a clause may be
amended to include some or all of the words (e.g., instructions,
operations, functions, or components) recited in other one or more
clauses, one or more sentences, one or more phrases, one or more
paragraphs, and/or one or more claims.
[0230] To illustrate the interchangeability of hardware and
software, items such as the various illustrative blocks, modules,
components, methods, operations, instructions, and algorithms have
been described generally in terms of their functionality. Whether
such functionality is implemented as hardware or software depends
upon the particular application and design constraints imposed on
the overall system. Skilled artisans may implement the described
functionality in varying ways for each particular application.
[0231] A reference to an element in the singular is not intended to
mean one and only one unless specifically so stated, but rather one
or more. For example, "a" module may refer to one or more modules.
An element proceeded by "a," "an," "the," or "said" does not,
without further constraints, preclude the existence of additional
same elements.
[0232] Headings and subheadings, if any, are used for convenience
only and do not limit the present disclosure. The word exemplary is
used to mean serving as an example or illustration. To the extent
that the term include, have, or the like is used, such term is
intended to be inclusive in a manner similar to the term comprise
as comprise is interpreted when employed as a transitional word in
a claim. Relational terms such as first and second and the like may
be used to distinguish one entity or action from another without
necessarily requiring or implying any actual such relationship or
order between such entities or actions.
[0233] Phrases such as an aspect, the aspect, another aspect, some
aspects, one or more aspects, an implementation, the
implementation, another implementation, some implementations, one
or more implementations, an embodiment, the embodiment, another
embodiment, some embodiments, one or more embodiments, a
configuration, the configuration, another configuration, some
configurations, one or more configurations, the subject technology,
the disclosure, the present disclosure, other variations thereof
and alike are for convenience and do not imply that a disclosure
relating to such phrase(s) is essential to the subject technology
or that such disclosure applies to all configurations of the
subject technology. A disclosure relating to such phrase(s) may
apply to all configurations, or one or more configurations. A
disclosure relating to such phrase(s) may provide one or more
examples. A phrase such as an aspect or some aspects may refer to
one or more aspects and vice versa, and this applies similarly to
other foregoing phrases.
[0234] A phrase "at least one of" preceding a series of items, with
the terms "and" or "or" to separate any of the items, modifies the
list as a whole, rather than each member of the list. The phrase
"at least one of" does not require selection of at least one item;
rather, the phrase allows a meaning that includes at least one of
any one of the items, and/or at least one of any combination of the
items, and/or at least one of each of the items. By way of example,
each of the phrases "at least one of A, B, and C" or "at least one
of A, B, or C" refers to only A, only B, or only C; any combination
of A, B, and C; and/or at least one of each of A, B, and C.
[0235] It is understood that the specific order or hierarchy of
steps, operations, or processes disclosed is an illustration of
exemplary approaches. Unless explicitly stated otherwise, it is
understood that the specific order or hierarchy of steps,
operations, or processes may be performed in different order. Some
of the steps, operations, or processes may be performed
simultaneously. The accompanying method claims, if any, present
elements of the various steps, operations or processes in a sample
order, and are not meant to be limited to the specific order or
hierarchy presented. These may be performed in serial, linearly, in
parallel or in different order. It should be understood that the
described instructions, operations, and systems can generally be
integrated together in a single software/hardware product or
packaged into multiple software/hardware products.
[0236] The disclosure is provided to enable any person skilled in
the art to practice the various aspects described herein. In some
instances, well-known structures and components are shown in block
diagram form in order to avoid obscuring the concepts of the
subject technology. The disclosure provides various examples of the
subject technology, and the subject technology is not limited to
these examples. Various modifications to these aspects will be
readily apparent to those skilled in the art, and the principles
described herein may be applied to other aspects.
[0237] All structural and functional equivalents to the elements of
the various aspects described throughout the disclosure that are
known or later come to be known to those of ordinary skill in the
art are expressly incorporated herein by reference and are intended
to be encompassed by the claims. Moreover, nothing disclosed herein
is intended to be dedicated to the public regardless of whether
such disclosure is explicitly recited in the claims. No claim
element is to be construed under the provisions of 35 U.S.C. .sctn.
112, sixth paragraph, unless the element is expressly recited using
a phrase means for or, in the case of a method claim, the element
is recited using the phrase step for.
[0238] The title, background, brief description of the drawings,
abstract, and drawings are hereby incorporated into the disclosure
and are provided as illustrative examples of the disclosure, not as
restrictive descriptions. It is submitted with the understanding
that they will not be used to limit the scope or meaning of the
claims. In addition, in the detailed description, it can be seen
that the description provides illustrative examples and the various
features are grouped together in various implementations for the
purpose of streamlining the disclosure. The method of disclosure is
not to be interpreted as reflecting an intention that the claimed
subject matter requires more features than are expressly recited in
each claim. Rather, as the following claims reflect, inventive
subject matter lies in less than all features of a single disclosed
configuration or operation. The following claims are hereby
incorporated into the detailed description, with each claim
standing on its own as a separately claimed subject matter.
[0239] The claims are not intended to be limited to the aspects
described herein, but are to be accorded the full scope consistent
with the language claims and to encompass all legal equivalents.
Notwithstanding, none of the claims are intended to embrace subject
matter that fails to satisfy the requirements of the applicable
patent law, nor should they be interpreted in such a way.
* * * * *