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.

What is claimed is: 
     
         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.