US Patent No. 9,252,991

SUB-BAND FEEDBACK FOR BEAMFORMING ON DOWNLINK MULTIPLE USER MIMO CONFIGURATIONS


Patent No. 9,252,991
Issue Date February 02, 2016 
Title Sub-band Feedback For Beamforming On Downlink Multiple User Mimo Configurations
Inventorship Hongyuan Zhang, Fremont, CA (US)
Assignee MARVELL WORLD TRADE LTD., St. Michael (BB)

Claim of US Patent No. 9,252,991

1. A method in a communication network, the method comprising:
(i) receiving, at a client device, a sounding packet from an access point device over a wireless downlink communication channel
having a plurality of 20 MHz-wide subchannels, the sounding packet having a packet bandwidth that spans the plurality of 20
MHz-wide subchannels;

(ii) at the client device, identifying a subchannel block of the sounding packet, wherein the subchannel block spans only
a subset of the plurality of 20 MHz-wide subchannels, and the subchannel block has a subchannel block contiguous bandwidth
that is a) at least 20 MHz and b) smaller than the packet bandwidth of the sounding packet;

(iii) performing a channel estimation (a) on the subchannel block, but (b) not on any other 20 MHz-wide subchannels of the
plurality of 20 MHz-wide subchannels, to determine a partial channel estimation of the downlink communication channel; and

(iv) communicating, to the access point in a feedback frame, the partial channel estimation of the downlink communication
channel so that the access point can determine a steering matrix from the partial channel estimation for application to only
a portion, in frequency, of an information carrying data packet, transmitted by the access point, when the information carrying
data packet has a bandwidth larger than the subchannel block, wherein the feedback frame includes an indication of a bandwidth
of the subchannel block to which the partial channel estimation corresponds, wherein the portion of the information carrying
data packet corresponds in frequency to the subchannel block.