Channel-dependent scheduling of an uplink SC-FDMA system with imperfect channel information

Channel-dependent scheduling (CDS) can increase the data throughput of a cellular system by exploiting multi-user diversity and frequency selectivity in the channel. In this paper, we investigate the impact of imperfect channel state information (CSI) on CDS. Specifically, we analyze the data throughput of an uplink single carrier FDMA (SC-FDMA) system with uncoded adaptive modulation and CDS when there is a CSI feedback delay. We consider distributed and localized subcarrier mapping schemes for resource allocation. We show that localized subcarrier mapping yields highest aggregate data throughput when we use CDS. However, we also show that localized mapping is very sensitive to the quality of CSI and the capacity gain quickly decreases when the channel changes rapidly. For high mobility users, distributed mapping with static round-robin scheduling is more suitable.