Analysis of the Dynamic Ordered Decoding for Uplink NOMA Systems With Imperfect CSI

Instead of successive interference cancellation (SIC) with fixed decoding order, we investigate the dynamic-ordered decoding scheme based on the estimated instantaneous received signal power in case of imperfect channel state information (CSI) for uplink nonorthogonal multiple access systems. The impacts of channel estimation error on both decoding process and order determination are theoretically analyzed in terms of the outage probability for each user. From our analysis, imperfect CSI introduces not only extra interference on the desired signal but also the incorrect decoding order. As shown in the simulations, the dynamic-ordered SIC receiver outperforms the traditional fixed one in case of good quality of estimated CSI. However, the advantage decreases with poor channel estimation quality.