High efficiency long training field symbol transmission for multiple transmission streams
摘要
說明書
By transmitting the spatial streams of users across tones using the tone multiplexing of streams described herein, the power fluctuation is minimized during the generation of HE-LTF symbols. In this transmission scheme, the access point transmits P016×16 at tones k %4=0, P116×16 at tones k %4=1, P216×16 at tones k %4=2, and P316×16 at tones k %4=3. The 16×16 Pk16×16 P-matrices used are generated from the advanced 16×16 P-matrix by shifting its rows down by k in a cyclical order based on the modulo operation to the tone index k. User 1 receives, in some implementations, Yu1,k,LTF1, a 4×1 vector, during HE-LTF1. Yu1,k,LTF1 is given as Yu1,k,LTF1=Hu1,k*Qmatk*P016×16=Hu1,k*q1k for k %4=0, Yu1,k,LTF1=Hu1,k*Qmatk*P116×16=Hu1,k*q2k for k %4=1, Yu1,k,LTF1=Hu1,k*Qmatk*P216×16=Hu1,k*q3k for k %4=2 and Yu1,k,LTF1=Hu1,k*Qmatk*P316×16=Hu1,k*q4k for k %4=3. For tones k %4=0, Yu1,k,LTF1 represents the contribution of only the 1st stream of user 1. For tones k %4=1, Yu1,k,LTF1 represents the contribution of only the 2nd stream of user 1. For tones k %4=2, Yu1,k,LTF1 represents the contribution of only the 3rd stream of user 1. For tones k %4=3, Yu1,k,LTF1 represents the contribution of only the 4th stream of user 1. The sum of power across 4 consecutive sets of tones transmitted in HE-LTF1 is represented by ΣHu1,r*qrr. This power is, in some implementations, similar across all HE-LTF symbols and also with respect to the power of the HE-STF symbol when summed across a set of 4 consecutive tones.
