High efficiency long training field symbol transmission for multiple transmission streams
摘要
說明書
Carrier phase error (CPE) compensation is, in some embodiments, achieved through the implementation of the advanced P-matrix design described herein. Up-link (UL) packets are frequency synchronized up to +/?400 Hz (e.g., within a range of 400 Hz), and CPE is not expected to build up significantly over a few HE-LTF symbols (e.g., four or less HE-LTF symbols). However, as the total number of streams and accordingly, HE-LTF symbols transmitted increases, the CPE build up increases and impacts HE-LTF symbols received later in the sequence of transmitted HE-LTF symbols significantly.
In some embodiments, transmitter 102 uses at least 16 antennas (e.g., antennas 103) to communicate with 4 users. Each user sends 4 streams of UL packets. Hence, the total number of HE-LTF symbols in an UL packet is 16 HE-LTF symbols. Using the advanced P-matrix design, rows 1 through 4 of the P16×16 correspond to user 1, rows 5 through 8 correspond to user 2, rows 9 through 12 correspond to user 3, and rows 13 through 16 correspond to user 4. The advanced P-matrix described earlier for channel estimation is used for mapping HE-LTF symbols transmitted over data tones while pilot tones are mapped using an R-matrix created through an advanced R-matrix design.
The R-matrix, in some implementations, is designed based on the P16×16 used for channel estimation. Columns 1 through 4 of P16×16 are used for columns 1 through 16 of R16×16 shown below.
