High efficiency long training field symbol transmission for multiple transmission streams
摘要
說明書
When the number of users is less than or equal to 4, the HE-LTF from different users are, in some implementations, present in different tones. Calibration-related issues from one user does not affect the channel estimation for other users. Additionally, a separate CPE estimation is needed for each user. Carrier frequency offset (CFO) estimation is performed, in some embodiments, per user and the effective CFO correction is computed and applied to obtain channel estimates. When the number of users is greater than 4, the overlapping of users in each tone is, in some implementations, limited and in turn, reduces the estimation error.
The receiver complexity, in some implementations, allows for a certain computational complexity for an undo P operation (e.g., undo P up to a 4×4 P-matrix). In some embodiments, a transmitter applies only the advanced P-matrix design and the HE-STF is represented by HESTFk=H*Qmat*ones(16,1) where k represents a tone index k, and Qmat is a precoder matrix (i.e., Q for a multi-user or beamformed steered transmission system is known as a precoder matrix while Q for a single-user transmission system is a spatial mapping matrix) and the transmitted HE-LTF symbols are represented by
