Quantized successor pre-coding : a method for spatial multiplexing in MIMO systems with limited feedback and temporally-correlated channels

The use of feedback to provide channel state information to the transmitter can greatly improve the performance of a communication system. However, the amount of information required to characterize a time-varying MIMO channel can exceed the capacity of the feedback channel. This paper surveys research in limited feedback systems, which employ a number of methods to reduce the information and improve performance in multi-antenna communication systems. This paper also presents a new method, Quantized Successor Pre-coding (QSP), that exploits time-correlation to implement spatial multiplexing in a MIMO system using very little feedback. QSP uses an ordered codebook of pre-coders and transmission modes to reduce the feedback to a single bit. Simulations of QSP demonstrate a substantial performance improvement relative to open-loop spatial multiplexing.