Data feedback methods and related apparatuses

Abstract

A data feedback method 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, a quantity of columns from a null data packet announcement (NDPA) message;   detecting, by the beamformee, a quantity of active first spatial streams;   comparing, by the beamformee, a quantity of first spatial streams and the quantity of columns;   determining a smaller value obtained from the comparison to be a quantity of second spatial streams required for feedback; and   feeding back, by the beamformee, the quantity 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 , wherein before acquiring, by the beamformee, the quantity of columns from the NDPA message, the method further comprises:
 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 acquisition of the quantity of columns from the NDPA message if AID matching succeeds.   
     
     
         4 . The method according to  claim 3 , wherein the matching, by the beamformee, the AID of the STA Info field in the NDPA message comprises:
 extracting, by the beamformee, STA information fields sequentially from the NDPA message; and   comparing, by the beamformee, AIDs of the STA information fields with a locally stored AID one by one;   determining that AID matching succeeds when one of the AIDs matches the locally stored AID; and   determining that ADI matching is unsuccessful otherwise.   
     
     
         5 . The method according to  claim 3 , wherein before comparing, by the beamformee, the quantity of first spatial streams and the quantity of columns, the method further comprises:
 receiving, by the beamformee, a null data packet (NDP) message;   determining whether the locally stored AID is equal to the AID of the first STA information field in the NDPA message; and,   if the locally stored AID is equal to the AID of the first STA information field in the NDPA message, comparing the quantity of first spatial streams with the quantity of columns.   
     
     
         6 . The method according to  claim 5 , wherein before feeding back, by the beamformee, the quantity of second spatial streams and spatial stream measurement information about the second spatial streams to the beamformer, the method further comprises:
 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 feeding back, by the beamformee, the quantity of second spatial streams and spatial stream measurement information about the second spatial streams to a beamformer comprises:
 encapsulating, by the beamformee, the quantity of second spatial streams and spatial stream measurement information about each of the second spatial streams in a very high throughput (VHT) compressed beamforming message; and   feeding back, by the beamformee, the VHT compressed beamforming message to the beamformer.   
     
     
         8 . A beamformee, comprising:
 a first acquiring unit configured to acquire a quantity of columns from a null data packet announcement NDPA message;   a detection unit configured to detect a quantity of active first spatial streams;   a comparison unit configured to compare a quantity of first spatial streams with the quantity of columns;   a determination unit configured to determine a smaller value obtained from the comparison to be a number of second spatial streams required for feedback; and   a feeding back unit, configured to feed back the number of second spatial streams and spatial stream measurement information about the second spatial streams to a beamformer.   
     
     
         9 . The beamformee according to  claim 8 , 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) information field in the NDPA message, and trigger the first acquiring unit to acquired the NDPA message if AID matching succeeds.   
     
     
         10 . The beamformee according to  claim 8 , 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 information field in the NDPA message, and, if the locally cached AID is equal to the AID of the first STA information field, 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.