U.S. patent application number 13/838420 was filed with the patent office on 2013-08-22 for data feedback methods and related apparatuses.
This patent application is currently assigned to Huawei Technologies Co., Ltd.. The applicant listed for this patent is Huawei Technologies Co., Ltd.. Invention is credited to Menghong Liu, Linfeng Xia, Zongming Yao.
Application Number | 20130215947 13/838420 |
Document ID | / |
Family ID | 47882614 |
Filed Date | 2013-08-22 |
United States Patent
Application |
20130215947 |
Kind Code |
A1 |
Yao; Zongming ; et
al. |
August 22, 2013 |
DATA FEEDBACK METHODS AND RELATED APPARATUSES
Abstract
Embodiments of the present invention disclose data feedback
methods and related apparatuses. This enables a beamformer to
adjust the communication status according to related channel
information about a beamformee no matter whether the number of
actual active antennas of the beamformee is larger than or equal to
the number of columns set by the beamformer in an NDPA message. The
data feedback method according to the embodiments of the present
invention includes: acquiring, by the beamformee, the number of
columns from the NDPA message; detecting the number of active first
spatial streams; comparing the number of first spatial streams with
the number of columns, and taking the smaller value obtained from
the comparison as the number of second spatial streams required for
feedback; and feeding back the number of second spatial streams and
spatial stream measurement information about the second spatial
streams to the beamformer.
Inventors: |
Yao; Zongming; (Chengdu,
CN) ; Liu; Menghong; (Shenzhen, CN) ; Xia;
Linfeng; (Chengdu, CN) |
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Applicant: |
Name |
City |
State |
Country |
Type |
Huawei Technologies Co., Ltd.; |
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|
US |
|
|
Assignee: |
Huawei Technologies Co.,
Ltd.
Shenzhen
CN
|
Family ID: |
47882614 |
Appl. No.: |
13/838420 |
Filed: |
March 15, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/CN2012/081255 |
Sep 11, 2012 |
|
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13838420 |
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Current U.S.
Class: |
375/224 ;
375/267 |
Current CPC
Class: |
H04B 7/0617 20130101;
H04B 7/0408 20130101; H04B 7/063 20130101; H04B 7/0452 20130101;
H04B 7/0417 20130101 |
Class at
Publication: |
375/224 ;
375/267 |
International
Class: |
H04B 7/04 20060101
H04B007/04 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 14, 2011 |
CN |
201110271898.2 |
Claims
1. A data feedback method, comprising: acquiring, by a beamformee,
the number of columns from a null data packet announcement NDPA
message; detecting, by the beamformee, the number of active first
spatial streams; comparing, by the beamformee, the number of first
spatial streams and the number of columns, and taking the smaller
value obtained from the comparison as the number of second spatial
streams required for feedback; and feeding back, by the beamformee,
the number of second spatial streams and spatial stream measurement
information about the second spatial streams to a beamformer.
2. The method according to claim 1, wherein the spatial stream
measurement information comprises: average signal-to-noise ratio
information, feedback matrix V information, and delta
signal-to-noise ratio information that correspond to each of the
second spatial streams.
3. The method according to claim 1, before the acquiring, by a
beamformee, the number of columns from a null data packet
announcement NDPA message, comprising: acquiring, by the
beamformee, the NDPA message; matching, by the beamformee, an
association ID AID of a station information STA Info field in the
NDPA message; and triggering a step to acquire the number of
columns from the NDPA message if AID matching succeeds.
4. The method according to claim 3, wherein the matching, by the
beamformee, an AID of a STA Info field in the NDPA message
comprises: extracting, by the beamformee, STA Info fields
sequentially from the NDPA message; and comparing, by the
beamformee, AIDs of the STA Info fields with a locally stored AID
one by one: if a same AID is found, AID matching succeeds; and if
no same AID is found, AID matching fails.
5. The method according to claim 3, before the comparing, by the
beamformee, the number of first spatial streams and the number of
columns, comprising: receiving, by the beamformee, a null data
packet NDP message and detecting whether the locally stored AID is
equal to the AID of the first STA Info field in the NDPA message,
and, if yes, triggering the step to compare the number of first
spatial streams with the number of columns.
6. The method according to claim 5, before the feeding back, by the
beamformee, the number of second spatial streams and spatial stream
measurement information about the second spatial streams to a
beamformer, comprising: calculating, by the beamformee, the spatial
stream measurement information about each of the second spatial
streams according to the received NDP message.
7. The method according to claim 1, wherein the feeding back, by
the beamformee, the number of second spatial streams and spatial
stream measurement information about the second spatial streams to
a beamformer comprises: encapsulating, by the beamformee, the
number of second spatial streams and spatial stream measurement
information about each of the second spatial streams in a VHT
Compressed Beamforming message; and feeding back, by the
beamformee, the VHT Compressed Beamforming message to the
beamformer.
8. A data feedback method, comprising: acquiring, by a beamformee,
the number of columns from a null data packet announcement NDPA
message; detecting, by the beamformee, the number of active spatial
streams; and determining, by the beamformee, whether the number of
spatial streams is smaller than the number of columns, and, if yes,
feeding back a null data packet to a beamformer.
9. The method according to claim 8, wherein the feeding back a null
data packet to a beamformer comprises: assembling, by the
beamformee, a VHT Compressed Beamforming message, wherein the VHT
Compressed Beamforming message carries null feedback matrix V
information; and feeding back, by the beamformee, the VHT
Compressed Beamforming message to the beamformer.
10. A beamformee, comprising: a first acquiring unit, configured to
acquire the number of columns from a null data packet announcement
NDPA message; a detection unit, configured to detect the number of
active first spatial streams; a comparison unit, configured to
compare the number of first spatial streams with the number of
columns, and take the smaller value obtained from the comparison as
the number of second spatial streams required for feedback; and a
feedback unit, configured to feed back the number of second spatial
streams and spatial stream measurement information about the second
spatial streams to a beamformer.
11. The beamformee according to claim 10, further comprising: a
second acquiring unit, configured to acquire an NDPA message; and a
matching unit, configured to match an association ID AID of a
station information STA Info field in the NDPA message, and trigger
the first acquiring unit if AID matching succeeds.
12. The beamformee according to claim 10, further comprising: a
receiving unit, configured to receive an NDP message, detect
whether a locally cached AID is equal to the AID of the first STA
Info field in the NDPA message, and, if yes, trigger the comparison
unit; and a measurement information calculating unit, configured to
calculate spatial stream measurement information about each of the
second spatial streams according to the received NDP message after
the number of second spatial streams required for feedback is
determined.
13. A beamformee, comprising: a unit for acquiring the number of
columns, configured to acquire the number of columns from a null
data packet announcement NDPA message; a unit for detecting the
number of spatial streams, configured to detect the number of
active spatial streams; a determining unit, configured to determine
whether the number of spatial streams is smaller than the number of
columns, and, if yes, trigger a null data packet feedback unit; and
the null data packet feedback unit, configured to feed back a null
data packet to a beamformer.
14. The beamformee according to claim 13, wherein the null data
packet feedback unit comprises: a null data packet assembly unit,
configured to assemble a VHT Compressed Beamforming message,
wherein the VHT Compressed Beamforming message carries null
feedback matrix V information; and a null data packet feedback
module, configured to feed back the VHT Compressed Beamforming
message to the beamformer.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of International
Application No. PCT/CN2012/081255,
filed on Sep. 11, 2012, which claims priority to Chinese Patent
Application No. 201110271898.2, filed on Sep. 14, 2011, both of
which are hereby incorporated by reference in their entireties.
FIELD OF THE INVENTION
[0002] The present invention relates to the communications field,
and in particular, to data feedback methods and related
apparatuses.
BACKGROUND OF THE INVENTION
[0003] IEEE802.11ac is a branch of the IEEE802.11 protocol series
and introduces a very-high-throughput probing mechanism, which is a
channel detection mechanism between a beamformer and a beamformee.
With this mechanism, the beamformer is capable of better knowing
the situation of a channel between the beamformer and the
beamformee. As such, the communication status can be improved by
adjusting related parameters. In general, on a network constructed
of a basic service set (BSS, Basic Service Set), the corresponding
physical device of the Beamformer is an access point (AP, Access
point) and that of the Beamformee is a station (STA, Station); and
on a network that is not constructed of a basic service set, the
corresponding physical device of the Beamformer may be a certain
STA and that of the Beamformee may be another STA.
[0004] In the prior art, to prevent abnormal situations,
IEEE802.11ac specifies that the number of actual active antennas of
the beamformee must be larger than or equal to the number of
columns (NC) set by the beamformer in a null data packet
announcement (NDPA, Null data packet Announcement) message.
Therefore, after receiving the NDPA message, the beamformee has no
corresponding processing mechanism if it finds that the number of
its actual active antennas is smaller than the number of columns
set by the beamformer in the NDPA message. This leads to logical
imprecision and disorder of IEEE802.11ac, finally affecting the
design of related products.
SUMMARY OF THE INVENTION
[0005] Embodiments of the present invention provide a data feedback
method and related apparatuses. This enables a beamformer to
adjust, according to related channel information fed back from a
beamformee, the communication status no matter whether the number
of actual active antennas of the beamformee is larger than or equal
to the number of columns set by the beamformer in an NDPA
message.
[0006] A data feedback method provided in the present invention
includes: acquiring, by a beamformee, the number of columns from a
null data packet announcement NDPA message; detecting the number of
active first spatial streams; comparing the number of first spatial
streams with the number of columns and taking the smaller value
obtained from the comparison as the number of second spatial
streams required for feedback; and feeding back the number of
second spatial streams and corresponding spatial stream measurement
information about second spatial streams to a beamformer.
[0007] A data feedback method provided in the present invention
includes: acquiring, by a beamformee, the number of columns from a
null data packet announcement NDPA message; detecting, by the
beamformee, the number of active spatial streams; and determining,
by the beamformee, whether the number of spatial streams is smaller
than the number of columns, and, if yes, feeding back a null data
packet to a beamformer.
[0008] A method for sending a null data packet announcement message
provided in the present invention includes: acquiring, by a
beamformer, the number of active antennas of a beamformee during a
capability negotiation process between the beamformer and the
beamformee; setting, by the beamformer, the number of columns in an
NDPA message according to the number of the antennas so that the
number of columns is smaller than the number of the antennas; and
sending, by the beamformer, the NDPA message to the beamformee.
[0009] A beamformee provided in the present invention includes: a
first acquiring unit, configured to acquire the number of columns
from a null data packet announcement NDPA message; a detection
unit, configured to detect the number of active first spatial
streams; a comparison unit, configured to compare the number of
first spatial streams with the number of columns and take the
smaller value obtained from the comparison as the number of second
spatial streams required for feedback; and a feedback unit,
configured to feed back the number of second spatial streams and
corresponding spatial stream measurement information to a
beamformer.
[0010] A beamformee provided in the present invention includes: a
unit for acquiring the number of columns, configured to acquire the
number of columns from a null data packet announcement NDPA
message; a unit for detecting the number of spatial streams,
configured to detect the number of active spatial streams; and a
determining unit, configured to determine whether the number of
spatial streams is smaller than the number of columns, and, if yes,
trigger a null data packet feedback unit; and the null data packet
feedback unit, configured to feed back a null data packet to a
beamformer.
[0011] A beamformer provided in the present invention includes: a
unit for acquiring the number of antennas, configured to acquire
the number of active antennas of a beamformee during a capability
negotiation process between the beamformer and the beamformee; a
unit for setting the number of columns, configured to set the
number of columns in an NDPA message according to the number of
antennas so that the number of columns is smaller than the number
of antennas; and a message sending unit, configured to send the
NDPA message to the beamformee.
[0012] It can be seen from the preceding technical solutions that,
the embodiments of the present invention have the following
advantages: By comparing the number of active first spatial streams
with the number of columns, a beamformee according to an embodiment
of the present invention takes the obtained smaller value as the
number of second spatial streams required for feedback and feeds
back this correct number of active second spatial streams to a
beamformer. In this way, the beamformer is capable of timely
knowing its actual communication status and correspondingly
optimizing and adjusting the communication status.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a schematic flowchart of a data feedback method
according to an embodiment of the present invention;
[0014] FIG. 2 is another schematic flowchart of a data feedback
method according to an embodiment of the present invention;
[0015] FIG. 3 is a signaling flowchart of a data feedback method
according to an embodiment of the present invention;
[0016] FIG. 4 is another signaling flowchart of a data feedback
method according to an embodiment of the present invention;
[0017] FIG. 5 is another schematic flowchart of a data feedback
method according to an embodiment of the present invention;
[0018] FIG. 6 is a schematic flowchart of a method for sending a
null data packet announcement message according to an embodiment of
the present invention;
[0019] FIG. 7 is a schematic flowchart of a beamformee according to
an embodiment of the present invention;
[0020] FIG. 8 is another schematic flowchart of a beamformee
according to an embodiment of the present invention; and
[0021] FIG. 9 is a schematic flowchart of a beamformer according to
an embodiment of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0022] The embodiments of the present invention provide a data
feedback method and related apparatuses. This enables a beamformer
to adjust, according to related channel information about a
beamformee, the communication status no matter whether the number
of actual active antennas of the beamformee is larger than or equal
to the number of columns set by the beamformer in an NDPA message.
In general, on a network constructed of a basic service set (BSS,
Basic Service Set), the corresponding physical device of the
beamformer (Beamformer) is an access point (AP, Access point) and
that of the beamformee (Beamformee) is a station (STA, Station);
and on a network that is not constructed of a basic service set,
the corresponding physical device of the Beamformer may be a
certain STA and that of the Beamformee may be another STA.
[0023] Referring to FIG. 1, an embodiment of a data feedback method
in the present invention includes:
[0024] 101. A beamformee acquires the number of columns from a null
data packet announcement message sent by a beamformer.
[0025] The beamformee receives the NDPA message and determines that
the beamformee is the one requested by a beamformer to send
feedback, and extracts the number of columns of station information
(STA Info, STA Information) from the NDPA message, where the number
of columns is obtained by adding 1 to the value of the Nc Index
field set by the beamformer in the NDPA message and is used to
indicate the number of spatial streams that a STA needs to feed
back.
[0026] 102. The beamformee detects the number of active first
spatial streams.
[0027] The beamformee detects spatial streams where data
transmission exists and determines the number of active first
spatial streams.
[0028] 103. The beamformee compares the number of first spatial
streams with the number of columns.
[0029] The beamformee compares the number of active first spatial
streams with the number of columns in the NDPA message, and takes
the smaller value obtained from the comparison as the number of
second spatial streams required for feedback.
[0030] IEEE802.11ac specifies that the number of actual active
antennas of the beamformee must be larger than or equal to the
number of columns set by the beamformer in the NDPA message.
However, in practical applications, the number of active antennas
of the beamformee may be smaller than the number of columns set by
the beamformer in the NDPA message because the beamformer has sent
a probing request when the beamformee does not timely inform the
beamformer of its reconfiguration or the beamformee cannot detect
the actual number of antennas due to an antenna failure, or the
like. In this case, if the beamformee forcedly feeds back certain
invalid information about spatial streams that are not supported or
the beamformee does not send feedback, the beamformer will
incorrectly estimate the current channel situation or cannot
optimize the communication status, thereby affecting the actual
communication effect between the beamformee and the beamformer.
However, in the embodiment of the present invention, after the
number of first spatial streams is compared with the number of
columns, the smaller value obtained from the comparison is taken as
the number of second spatial streams required for feedback. In this
way, the beamformee is capable of feeding back the correct number
of current active spatial streams to the beamformer no matter
whether the number of actual active antennas of the beamformee is
larger than or equal to the number of columns set by the beamformer
in the NDPA message.
[0031] 104. The beamformee feeds back the number of second spatial
streams and corresponding spatial stream measurement information to
the beamformer.
[0032] After obtaining the number of second spatial streams, the
beamformee calculates spatial stream measurement information about
the second spatial streams and feeds back the number of second
spatial streams and corresponding spatial stream measurement
information to the beamformer. Therefore, the beamformer is capable
of calculating related operation matrix V according to the spatial
stream measurement information to guide subsequent receiving and
sending, thereby improving the communication performance of the
entire system.
[0033] The spatial stream measurement information may include:
average signal-to-noise ratio (Average SNR) information, feedback
matrix V (Feedback Matrix V) information, and delta signal-to-noise
ratio (Delta SNR) information that correspond to each spatial
stream.
[0034] To prevent abnormal situations, IEEE802.11ac specifies that
the number of actual active antennas of the beamformee must be
larger than or equal to the number of columns (NC) set by the
beamformer in the null data packet announcement (NDPA, Null data
packet Announcement) message. As such, the beamformee returns
related channel information about each of columns to the
beamformer. This enables the beamformer to adjust the communication
status according to the related channel information about each of
columns. If the number of actual active spatial streams of the
beamformee is smaller than the number of columns, the following two
results occur: 1. The beamformee may forcedly feed back, according
to the number of spatial streams that the number of columns
indicates, invalid information about certain spatial streams that
are not supported. However, the beamformer does not know this.
Therefore, the beamformer incorrectly estimates the current channel
situation and performs incorrect parameter configuration according
to the current channel situation; 2. the beamformee may consider
that it cannot support the number of spatial streams that the
number of columns indicates, so that the beamformee does not send
feedback. As such, the information about actual active spatial
streams of the beamformee cannot be known by the beamformer.
Therefore, the communication status cannot be optimized, greatly
affecting the actual communication effect of the beamformee.
[0035] By comparing the number of active first spatial streams with
the number of columns, the beamformee in the embodiment of the
present invention takes the smaller value obtained from the
comparison as the number of second spatial streams required for
feedback and feeds back this correct number of active second
spatial streams to the beamformer. In this way, the beamformer is
capable of timely knowing its actual communication status and
correspondingly optimizing and adjusting the communication
status.
[0036] For better understanding, the following describes in detail
the data feedback method in the preceding embodiment by using a
specific application scenario. Referring to FIG. 2, another
embodiment of a data feedback method according to the embodiments
of the present invention includes:
[0037] 201. A beamformee acquires a null data packet announcement
message.
[0038] A very-high-throughput probing mechanism may be applied to
two scenarios: single-user multiple input multiple output (SU-MIMO)
and multi-user multiple input multiple output (MU-MIMO)
scenarios.
[0039] In the SU-MIMO scenario, one beamformee communicates with
one beamformer (for a specific signaling flowchart, reference may
be made to FIG. 3, where TXOP indicates Transmit Opportunity, and
SIFS indicates Short Inter-Frame Space). Therefore, when the
beamformee receives a unicast NDPA message, the transmission is
SU-MIMO communication if a feedback type (Feedback Type) recorded
in a STA Info field in the NDPA message is 0. If a locally stored
association ID (AID, Association ID) matches the AID of the STA
Info in the NDPA, the NDPA message is what the beamformee
requires.
[0040] In the MU-MIMO scenario, one beamformer communicates with
multiple beamformees (for a specific signaling flowchart, reference
may be made to FIG. 4). Therefore, the NDPA message received by the
beamformees is a broadcast packet sent by the beamformer. As such,
when a beamformee receives the NDPA message, this transmission is
MU-MIMO communication if the feedback type (Feedback Type) recorded
in the STA Info field in the NDPA message is 1, and the beamformee
needs to perform AID matching.
[0041] 202. The beamformee performs association ID matching.
[0042] The beamformee extracts STA Info fields sequentially from
the NDPA message and compares AIDs of the STA Info fields one by
one with the locally stored AID. If a same AID is found, AID
matching succeeds, which indicates that the NDPA message needs to
be locally received. As such, the beamformee needs to feed back
spatial stream measurement information, and step 203 is triggered.
If a same AID is not found, AID matching fails, which indicates
that the beamformee is not the specified one that is requested to
send feedback.
[0043] 203. The beamformee acquires the number of columns from the
null data packet announcement.
[0044] After determining that the beamformee is the one requested
by the beamformer to send feedback, the beamformee extracts and
saves the number of columns and the feedback type of the STA Info
from the NDPA message.
[0045] 204. The beamformee detects the number of active first
spatial streams.
[0046] In this embodiment, the content of step 204 is the same as
that of step 102 in the preceding embodiment as shown in FIG. 1.
Therefore, the content is not mentioned herein.
[0047] 205. The beamformee receives a null data packet message or a
beamforming report poll message.
[0048] The beamformee receives the null data packet (NDP, Null Data
Packet) message and detects whether the locally stored AID is equal
to the AID of the first STA Info field in the NDPA message, and, if
yes, step 206 is triggered;
[0049] or,
[0050] the beamformee detects whether it has received the
beamforming report poll (Beamforming report poll) message, and, if
yes, step 206 is triggered.
[0051] Referring to FIG. 4, in the MU-MIMO scenario, the beamformer
first sends a broadcast packet of the NDPA message to instruct all
related beamformees to prepare for probing. Then, the beamformer
sends a broadcast packet of the NDP message, and all related
beamformees calculate related channel feedback information
according to the received broadcast packet of the NDP message. It
should be noted that after the broadcast packet of the NDP message
is received, spatial stream measurement information, which is
calculated according to the received NDP message, can be
immediately sent to the beamformer only when the AID of a
beamformee is equal to the AID of the first STA Info field in the
broadcast packet of the received NDPA message. For other
beamformees, when they receive the beamforming report poll
(Beamforming Report Poll) from the beamformer respectively, they
send spatial stream measurement information, which is calculated
according to the received broadcast packet of the NDP message, to
the beamformer if they have received the broadcast packet of the
NDP message; and if the broadcast packet of the NDP message is not
received, a null data packet or no feedback is sent to the
beamformer.
[0052] 206. The beamformee calculates spatial stream measurement
information about each of the second spatial streams.
[0053] The beamformee calculates the corresponding spatial stream
measurement information about each of the second spatial streams
according to the received NDP message.
[0054] 207. The beamformee feeds back the number of second spatial
streams and corresponding spatial stream measurement information to
the beamformer.
[0055] The beamformee feeds back the number of second spatial
streams and corresponding spatial stream measurement information to
the beamformer. This enables the beamformer to calculate, according
to the spatial stream measurement information, related operation
matrix V to guide subsequent receiving and sending, thereby
improving the communication performance of the entire system.
Specifically, the beamformee encapsulates the number of second
spatial streams and corresponding spatial stream measurement
information in a very high throughput compressed beamforming (VHT
Compressed Beamforming) message, and then feeds back the VHT
Compressed Beamforming message to the beamformer.
[0056] The application scenario of the embodiment of the present
invention is illustrated above through some examples only, and it
may be understood that, in actual applications, more application
scenarios may exist, which is not specifically limited herein.
[0057] In addition to the method described in the preceding
embodiment, another feedback mechanism can be used to prevent the
situation that a beamformer incorrectly estimates the current
channel situation or cannot optimize the communication status. For
details, refer to FIG. 5. Another embodiment of a data feedback
method in the present invention includes:
[0058] 501. A beamformee acquires the number of columns from a null
data packet announcement.
[0059] The beamformee receives the NDPA message and determines that
the beamformee is the one requested by a beamformer to send
feedback; and extracts the number of columns in STA Info from the
NDPA message, where the number of columns is a field set by the
beamformer in the NDPA message and is used to indicate the number
of spatial streams that a STA needs to feed back.
[0060] 502. The beamformee detects the number of active spatial
streams.
[0061] The beamformee detects spatial streams where data
transmission exists and determines the number of active spatial
streams.
[0062] 503. The beamformee determines whether the number of spatial
streams is smaller than the number of columns.
[0063] The beamformee determines whether the number of active
spatial streams is smaller than the number of columns in the NDPA
message. If yes, step 504 is triggered. If not, step 505 is
triggered.
[0064] 504. The beamformee feeds back a null data packet to the
beamformer.
[0065] The beamformee feeds back the null data packet to the
beamformer. Specifically, this may be that the beamformee assembles
a VHT Compressed Beamforming message, where the VHT Compressed
Beamforming message does not carry any spatial stream measurement
information, and then feeds back the VHT Compressed Beamforming
message to the beamformer.
[0066] In the embodiment of the present invention, the beamformee
feeds back the null data packet to the beamformer. This enables the
beamformer to know that the number of actual active spatial streams
of the beamformee is smaller than the number of columns set by the
beamformer in the NDPA message. In this way, the beamformer is
capable of making a timely response, for example, sending a new
NDPA message for measurement.
[0067] 505. The beamformee returns the number of columns and
corresponding spatial stream measurement information to the
beamformer.
[0068] After determining that the number of active spatial streams
is larger than or equal to the number of columns in the NDPA
message, the beamformee calculates the number of columns and
corresponding spatial stream measurement information according to a
received NDP message. After obtaining the corresponding spatial
stream measurement information about each of columns, the
beamformee returns the corresponding spatial stream measurement
information about each of columns to the beamformer. This enables
the beamformer to calculate, according to the spatial stream
measurement information, related operation matrix Q to guide
subsequent receiving and sending, thereby improving the
communication performance of the entire system. The operation
matrix Q is deduced by the beamformer according to the feedback
matrix V information sent by each beamformee and is used to
instruct the beamformer to receive and send data.
[0069] In addition to the preceding method at a beamformee end, an
embodiment of the present invention also provides a related method
for a beamformee to solve the problem in feeding back spatial
stream measurement information at a beamformer end. Referring to
FIG. 6, an embodiment of a method for sending a null data packet
announcement message in the present invention includes:
[0070] 601. A beamformer acquires the number of active antennas of
a beamformee.
[0071] During a capability negotiation process between the
beamformer and the beamformee, the beamformer acquires the number
of active antennas of the beamformee.
[0072] 602. The beamformer sets the number of columns in an NDPA
message according to the number of antennas.
[0073] During a very-high-throughput probing process between the
beamformer and the beamformee, the beamformer needs to send the
NDPA message to the beamformee. During the process that the
beamformer frames the NDPA message, the beamformer sets the number
of columns in the NDPA message according to the number of active
antennas of the beamformee so that the number of columns is smaller
than the number of antennas.
[0074] 603. The beamformer sends the NDPA message to the
beamformee.
[0075] The beamformer sends the NDPA message to the beamformee.
This enables the beamformee to feed back, according to the NDPA
message, the corresponding spatial stream measurement information
about each of columns.
[0076] In the embodiment of the present invention, during the
capability negotiation process with the beamformee, the beamformer
acquires the number of active antennas of the beamformee, so that
when framing the NDPA message, the beamformer can set the number of
columns according to that the number of active antennas of the
beamformee must be larger than or equal to the number of columns in
the NDPA message. Therefore, the beamformee end is capable of
feeding back correct and valid spatial stream measurement
information to the beamformer according to the existing 802.11ac
mechanism.
[0077] The following describes an embodiment in the present
invention of a beamformee that is configured to execute the
preceding data feedback method. For the logic structure, refer to
FIG. 7. The beamformee in an embodiment of the present invention
includes:
[0078] a first acquiring unit 701, configured to acquire the number
of columns from a null data packet announcement NDPA message;
[0079] a detection unit 702, configured to detect the number of
active first spatial streams;
[0080] a comparison unit 703, configured to compare the number of
first spatial streams with the number of columns, and take the
smaller value obtained from the comparison as the number of second
spatial streams required for feedback; and
[0081] a feedback unit 704, configured to feed back the number of
second spatial streams and spatial stream measurement information
about the second spatial streams to a beamformer.
[0082] In the embodiment of the present invention, the beamformee
may further include:
[0083] a second acquiring unit 705, configured to acquire the NDPA
message;
[0084] a matching unit 706, configured to match the AID of a STA
Info field in the NDPA message, and trigger the first acquiring
unit 701 if AID matching succeeds;
[0085] a receiving unit 707, configured to receive an NDP message,
detect whether a locally stored AID is equal to the AID of the
first STA Info field in the NDPA message, and, if yes, trigger the
comparison unit 703; and
[0086] a measurement information calculating unit 708, configured
to calculate spatial stream measurement information about each of
second spatial streams according to the received NDP message after
the number of second spatial streams required for feedback is
determined.
[0087] In the embodiment of the present invention, the specific
interaction process of each unit of the beamformee is as
follows:
[0088] The first acquiring unit 701 extracts the number of columns
in STA Info from the NDPA message, where the number of columns is a
field set by the beamformer in the NDPA message and is used to
indicate the number of spatial streams that a STA needs to feed
back.
[0089] The detection unit 702 detects spatial streams where data
transmission exists and determines the number of active first
spatial streams.
[0090] Before extraction of the number of columns in STA Info from
the NDPA message, the second acquiring unit 705 of the beamformee
first acquires the NDPA message. If the feedback type (Feedback
Type) recorded in the STA Info field in the NDPA message is 0, the
transmission is SU-MIMO communication. If the locally cached AID is
the same as the AID of the NDPA STA Info field, the NDPA message
needs to be received locally, and the beamformee needs to feed back
spatial stream measurement information. In addition, the first
acquiring unit 701 is triggered. Otherwise, the beamformee is not
the specified one that is requested to send feedback. If the
feedback type (Feedback Type) recorded in the STA Info field in the
NDPA message is 1, the transmission is MU-MIMU communication, and
the matching unit 706 needs to be triggered to match the
association ID AID of the station information STA Info field in the
NDPA message. Specifically, AID matching is as follows: The
matching unit 706 extracts STA Info fields sequentially from the
NDPA message and compares AIDs in the STA Info fields one by one
with the locally stored AID. If a same AID is found, AID matching
succeeds, which indicates that the NDPA message needs to be locally
received. As such, the beamformee needs to feed back the spatial
stream measurement information, and the first acquiring unit 701 is
triggered. If a same AID is not found, AID matching fails, which
indicates that the beamformee is not the specified one that is
requested to send feedback.
[0091] After the number of columns in the NDPA message and the
number of active first spatial streams are obtained, the comparison
unit 703 compares the number of active first spatial streams with
the number of columns in the NDPA message, and takes the smaller
value obtained from the comparison as the number of second spatial
streams required for feedback. Optionally, before the comparison
unit 703 executes the operation, the receiving unit 707 of the
beamformee receives the NDP message and detects whether the AID in
the NDP message is equal to the AID of the first STA Info field in
the NDPA message. If yes, the comparison unit 703 is triggered.
[0092] After the number of second spatial streams is determined,
the measurement information calculating unit 708 calculates the
corresponding spatial stream measurement information about each of
the second spatial streams according to the received NDP
message.
[0093] After the corresponding spatial stream measurement
information about each of the second spatial streams is obtained,
the feedback unit 704 feeds back the number of second spatial
streams and corresponding spatial stream measurement information to
the beamformer. This enables the beamformer to calculate, according
to the spatial stream measurement information, related operation
matrix Q to guide subsequent receiving and sending, thereby
improving the communication performance of the entire system.
Specifically, the beamformee encapsulates the number of second
spatial streams and corresponding spatial stream measurement
information in a very high throughput compressed beamforming (VHT
Compressed Beamforming) message, and then feeds back the VHT
Compressed Beamforming message to the beamformer.
[0094] The following describes an embodiment in the present
invention of a beamformee that is configured to execute the
preceding data feedback method. For the logic structure, refer to
FIG. 8. The beamformee in another embodiment of the present
invention includes:
[0095] a unit 801 for acquiring the number of columns, configured
to acquire the number of columns from a null data packet
announcement NDPA message;
[0096] a unit 802 for detecting the number of spatial streams,
configured to detect the number of active spatial streams;
[0097] a determining unit 803, configured to determine whether the
number of spatial streams is smaller than the number of columns,
and, if yes, trigger a null data packet feedback unit; and
[0098] a null data packet feedback unit 804, configured to feed
back a null data packet to a beamformer.
[0099] In the embodiment of the present invention, the null data
packet feedback unit may include:
[0100] a null data packet assembly module 8041, configured to
assemble a VHT Compressed Beamforming message, where the VHT
Compressed Beamforming message does not carry any spatial stream
measurement information; and
[0101] a null data packet feedback module 8042, configured to feed
back the VHT Compressed Beamforming message to the beamformer.
[0102] In the embodiment of the present invention, the specific
interaction process of each unit of the beamformee is as
follows:
[0103] The beamformee receives the NDPA message and determines that
the beamformee is the one requested by the beamformer to send
feedback; and the unit 801 for acquiring the number of columns
extracts the number of columns in STA Info from the NDPA message,
where the number of columns is a field set by the beamformer in the
NDPA message and is used to indicate the number of spatial streams
that a STA needs to feed back.
[0104] The unit 802 for detecting the number of spatial streams
detects spatial streams where data transmission exists and
determines the number of active spatial streams.
[0105] After the number of columns in the NDPA message and the
number of active spatial streams are obtained, the determining unit
803 determines whether the number of active spatial streams is
smaller than the number of columns in the NDPA message. If yes, the
null data packet feedback unit 804 is triggered to feed back a null
data packet to the beamformer. Specifically, this may be that the
null data packet assembly module 8041 assembles the VHT Compressed
Beamforming message, where the VHT Compressed Beamforming message
does not carry any spatial stream measurement information; and
then, the null data packet feedback module 8042 feeds back the VHT
Compressed Beamforming message to the beamformer.
[0106] The following describes an embodiment in the present
invention of a beamformer that is configured to execute the
preceding method for sending a null data packet announcement
message. For the logic structure, refer to FIG. 9. The beamformer
in an embodiment of the present invention includes:
[0107] a unit 901 for acquiring the number of antennas, configured
to acquire the number of active antennas of a beamformee during a
capability negotiation process between a beamformer and the
beamformee;
[0108] a unit 902 for setting the number of columns, configured to
set the number of columns in an NDPA message according to the
number of antennas so that the number of columns is smaller than
the number of antennas; and
[0109] a message sending unit 903, configured to send the NDPA
message to the beamformee.
[0110] In the embodiment of the present invention, the specific
interaction process of each unit of the beamformer is as
follows:
[0111] During the capability negotiation process between the
beamformer and the beamformee, the unit 901 for acquiring the
number of antennas in the beamformer acquires the number of active
antennas of the beamformee.
[0112] After the number of active antennas of the beamformee is
acquired, the beamformer needs to send the NDPA message to the
beamformee during a very-high-throughput probing process between
the beamformer and the beamformee. During the process that the
beamformer frames the NDPA message, the unit 902 for setting the
number of columns sets the number of columns in the NDPA message
according to the number of active antennas of the beamformee so
that the number of columns is smaller than the number of
antennas.
[0113] After the NDPA message is framed, the message sending unit
903 sends the NDPA message to the beamformee. This enables the
beamformee to feed back, according to the NDPA message, the
corresponding spatial stream measurement information about each of
columns. In the embodiment of the present invention, during the
capability negotiation process with the beamformee, the beamformer
acquires the number of active antennas of the beamformee, so that
when framing the NDPA message, the beamformer can set the number of
columns according to that the number of active antennas of the
beamformee must be larger than or equal to the number of columns in
the NDPA message. Therefore, the beamformee end is capable of
feeding back correct and valid spatial stream measurement
information to the beamformer according to the existing 802.11ac
mechanism.
[0114] In the several embodiments provided in the present
application, it should be understood that the disclosed apparatus
and method may be implemented in other manners. For example, the
described apparatus embodiment is merely exemplary. For example,
the unit division is merely logical function division and may be
other division in practical implementation. For example, a
plurality of units or components may be combined or integrated into
another system, or some features may be ignored or not performed.
In addition, the displayed or discussed mutual couplings or direct
couplings or communication connections may be implemented through
some interfaces. The indirect couplings or communication
connections between the apparatuses or units may be implemented in
electronic, mechanical, or other forms.
[0115] The units described as separate parts may or may not be
physically separate, and parts displayed as units may or may not be
physical units, may be located in one position, or may be
distributed on multiple network units. A part or all of the units
may be selected according to the actual needs to achieve the
objectives of the solutions of the embodiments.
[0116] In addition, functional units in the embodiments of the
present invention may be integrated into one processing unit, or
each of the units may exist alone physically, or two or more units
are integrated into one unit. The integrated unit may be
implemented in a form of hardware, or may be implemented in a form
of a software functional unit.
[0117] When the integrated units are implemented in the form of a
software functional unit and sold or used as an independent
product, the integrated unit may be stored in a computer-readable
storage medium. Based on such an understanding, the technical
solutions of the present invention essentially, or the part
contributing to the prior art, or all or a part of the technical
solutions may be implemented in the form of a software product. The
computer software product is stored in a storage medium and
includes several instructions for instructing a computer device
(which may be a personal computer, a server, a network device, and
the like) to perform all or a part of steps of the methods
described in the embodiments of the present invention. The storage
medium includes: any medium that can store program codes, such as a
USB flash disk, a removable hard disk, a read-only memory (ROM,
Read-Only Memory), a random access memory (RAM, Random Access
Memory), a magnetic disk, or an optical disk.
[0118] The foregoing descriptions are merely specific embodiments
of the present invention, but are not intended to limit the
protection scope of the present invention. Any variation or
replacement readily figured out by persons skilled in the art
within the technical scope disclosed in the present invention shall
all fall within the protection scope of the present invention.
Therefore, the protection scope of the present invention shall be
subject to the protection scope of the claims.
* * * * *