Hybrid MU-MIMO spatial mapping using both explicit sounding and crosstalk tracking in a wireless local area network
摘要
說明書
On the WAP, the packet disassembler 604 of the explicit channel sounding circuit 600 unpacks the channel information 606 from all the feedback packets from the stations in the MU-MIMO group. Then the WAP performs two calculations. The first calculation is the determination of a precode matrix “Q” for the spatial mapping the MU-MIMO downlink communication packet. That calculation may involve a singular value decomposition (SVD) 608 of the aggregated channel feedback 606 to determine the precode matrix “Q”. The second calculation is the determination of the pseudo inverse of the aggregate channels (PIAC) 610. The explicit channel sounding circuit initiates the transmission of the downlink transmission by assembling in the packet assembler 622 the MU-MIMO downlink packet including the VHT-LTF training field as well as the discrete “a” and “b” streams of data 620 in the payload of the MU-MIMO packet. The MU-MIMO packet including the training and payload fields is then spatially mapped with the precode matrix “Q” in the spatial mapper 626 and transmitted by the WAP's MIMO antenna array (not shown) to the downlink stations. The downlink MU-MIMO packet transmission exhibits an anisotropic RF signal strength profile 662A-B so that the distinct “a” and “b” portions of each downlink packet are each received at the corresponding one of the stations without interference/crosstalk from the portions destined for other stations in the MU-MIMO group. The explicit channel sounding circuit also outputs the precode matrix “Q” and PIAC to the crosstalk damping circuit 630.
