This paper investigates an uplink coordinated multi-point (CoMP) coverage scenario, in which multiple mobile users are grouped for sparse code multiple access (SCMA), and served by the remote radio head (RRH) in front of them and the RRH behind them simultaneously. We apply orthogonal time frequency space (OTFS) modulation for each user to exploit the degrees of freedom arising from both the delay and Doppler domains. As the signals received by the RRHs in front of and behind the users experience respectively positive and negative Doppler frequency shifts, our proposed OTFS-based SCMA (OBSCMA) with CoMP system can effectively harvest extra Doppler and spatial diversity for better performance. Based on maximum likelihood (ML) detector, we analyze the single-user average bit error rate (ABER) bound as the benchmark of the ABER performance for our proposed OBSCMA with CoMP system. We also develop a customized Gaussian approximation with expectation propagation (GAEP) algorithm for multi-user detection and propose efficient algorithm structures for centralized and decentralized detectors. Our proposed OBSCMA with CoMP system leads to stronger performance than the existing solutions. The proposed centralized and decentralized detectors exhibit effective reception and robustness under channel state information uncertainty.

翻译：本文调查了上链协调多点(CoMP)覆盖情景,在这种情景中,多移动用户按稀有代码多存(SCMA)分组,由远程无线电头(RRH)在他们前面服务,同时由他们后面的RRH服务。我们为每个用户应用正方位时频(OTFS)调制,以利用延迟和多普勒域产生的自由度。作为RRW在用户前面和后面分别经历正和负多普勒频率变化的信号,我们提议的基于OTFS的SCMA(OBSCMA)与CMP系统可以有效地采集额外的多普勒和空间多样性,以取得更好的性能。根据最大可能性(ML)探测器,我们分析了单一用户平均误差率(ABER),作为ABER与我们提议的OBSCMA(CMP)系统的运行基准。我们还开发了一种定制的Gausias近似近似值算法,用于多用户检测,并为集中和分散的探测器建议有效的算法结构。我们提议的OBSCMA(COMA)与中央级和中央级接收系统之下的拟议高频级系统将带来更强的强的状态。