非理想状态信息下SC-FDMA上行链路的信道调度

Channel Scheduling of Uplink SC-FDMA System with Imperfect State Information

信道依赖调度(CDS)通过在信道里使用多用户分集和频率选择性来增加蜂窝系统的数据吞吐量,主要研究非理想信道状态信息(CSI)对CDS的影响。具体来说,当CSI有反馈延时,分析具有未编码自适应调制及CDS的上行链路单载波频分多址(SC-FDMA)系统的数据吞吐量。频域资源分配采用集中式和分布式的子载波映射方案。通过仿真可以看到在应用CDS时,集中式的子载波映射产生最高的总数据吞吐量,然而,当信道迅速变化时,集中式映射对CSI的质量以及信道容量增益的迅速减少非常灵敏。对于高机动性的用户来说,具有静态轮询调度方案的分布式映射更加合适。

Channel-dependent scheduling（CDS） can increase the data throughput of a cellular system by exploiting multiuser diversity and frequency selectivity in the channel. In this paper, the impact of imperfect channel state information（CSI） on CDS is investigated. Specifically, the data throughput of an uplink single carrier FDMA （SC-FDMA） system with uncoded adaptive modulation is analyzed and CDS when there is a CSI feedback delay, distributed and localized subcarrier mapping schemes for resource allocation are considered, localized subcarrier mapping yields highest aggregate data throughput when we use CDS are showed. However, 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.