Channel Aware Aloha with Imperfect CSI

Abstract

Channel aware medium access protocols perform decisions primarily based on the instantaneous channel state information (CSI) available. In practice, channel measurements and quantization introduce distortion in the available CSI at the transmitter. In this paper, we investigate the effect of imperfect CSI on the asymptotic throughput of a particularly important medium access protocol - the channel aware Aloha. We show that any degree of uncertainty in the channel estimate leads to zero throughput asymptotically in the existing single carrier Aloha scheme; however, multicarrier diversity is effective in compensating for lack of perfect CSI.