Limited Feedback Multiuser MIMO Techniques for Time-Correlated Channels

Abstract

This work presents limited feedback schemes for closed-loop multiple-input multiple-output systems using frequency division duplex. The proposed methods employ compact feedback messages in order to (a) feed back and track a complete frequencyflat channel matrix, to be used as input to multiuser multiplexing methods designed for full channel side information (CSI) at the transmitter, and (b) enable the receiver to command the transmit weight adaptation, in order to maximize the link reliability under strong intercell interference. Simulations show that the channel feedback accuracy provided by the proposed algorithms produces a negligible bit error probability (BEP) performance loss in low mobility scenarios compared to the full CSI performance, and that the proposed interference rejection techniques can effectively exploit an estimate of the interference statistics in order to enable multiple-stream communications under the permanent presence of intercell interference signals.

Feedback‐based multi‐layered STBC system for MIMO multi‐cellular networks with cochannel interference

“…Apparently, the above system is an integrated diversity and spatial multiplexing system, in which $K = 1$ represents the diversity scheme, while $K = n_T $ represents the spatial multiplexing scheme, and it was called the multi‐layered STBC (MLSTBC) system in References 9, 10, 22. As assumed in most MIMO systems 1–13, 22–29, it is assumed that the receiver has perfect knowledge of the channel state (which can be derived by pilot symbol insertion and extraction).…”

“…Limited feedback in wireless communications has recently attracted much attention from researchers 11–14. Most limited feedback systems (such as the systems in Reference 11) let the receiver send a small number of information bits about the channel conditions to the transmitter so that the near optimal channel adaptation can be achieved.…”