A New Scheduling Algorithm for Time-varying MIMO Channels with a Channel Aging Metric

In a wireless communication system, channel aging produces a mismatch between the estimated channel and the channel state at the time of data transmission. This mismatch enhances the interference to users and degrades system capacity. In this paper, we first define a channel aging metric (CAM) to reflect the influence of channel aging on user scheduling. We then propose a CAM-based semiorthogonal user scheduling (CAMSUS) algorithm that adaptively adjusts the number of serving users according to the user's CAM. Specifically, the CAMSUS algorithm reduces the number of serving users to mitigate intra-user interference (IUI) when channel aging is severe, and otherwise increases the number to increase the multiplexing gain. Simulation results show the proposed algorithm outperforms the SUS algorithm in a time-varying channel in terms of signal-tointerference-plus-noise ratio by 6-7 dB, and the achievable rate by 39-41%.