Rate-maximized adaptive MIMO systems with channel state information feedback delays

This paper discusses rate-maximized adaptive modulation for multiple-input multiple-output (MIMO) systems and its receiver detection procedure when channel state information (CSI) feedback is of feedback period and delay. A set of equivalent parallel fading subchannels is obtained by singular value decomposition (SVD). The fading factors and independence of the subchannels in the ideal case when the precise CSI is available at the transmitter are altered due to the time-varying characteristics of wireless MIMO channels. However, the correlation remains within a very short period of time. Zero forcing (ZF) and interference cancellation (IC) are adopted at the receiver to improve the performance.