在通用化 CSIT 下, D2D 辅助多天多播 (D2D-Aided Multi-Antenna Multicasting under Generalized CSIT)

Multicasting, where a base station (BS) wishes to convey the same message to several user equipments (UEs), represents a common yet highly challenging wireless scenario. In fact, guaranteeing decodability by the whole UE population proves to be a major performance bottleneck since the UEs in poor channel conditions ultimately determine the achievable rate. To overcome this issue, two-phase cooperative multicasting schemes, which use conventional multicasting in a first phase and leverage device-to-device (D2D) communications in a second phase to effectively spread the message, have been extensively studied. However, most works are limited either to the simple case of single-antenna BS or to a specific channel state information at the transmitter (CSIT) setup. This paper proposes a general two-phase framework that is applicable to the cases of perfect, statistical, and topological CSIT in the presence of multiple antennas at the BS. The proposed method exploits the precoding capabilities at the BS, which enable targeting specific UEs that can effectively serve as D2D relays towards the remaining UEs, and maximize the multicast rate under some outage constraint. Numerical results show that our schemes bring substantial gains over traditional single-phase multicasting and overcome the worst-UE bottleneck behavior in all the considered CSIT configurations.

翻译：多式播音,即一个基站(BS)希望向若干用户设备传达相同信息,这是常见的但极具挑战性的无线情景。事实上,保证整个UE人口的可腐化性证明是一个重要的绩效瓶颈,因为低频道条件下的Ues最终决定了可实现的速率。为解决这一问题,已广泛研究了两阶段合作多式播音计划,在第一阶段使用常规多播和在第二阶段利用设备对设备对设备(D2D)通信有效传播信息的两阶段合作多式多式播音计划,在第二阶段能够有效地将特定Ues作为D2D中继器,进入其余的UIS BS或发射台(CSIT)的某个特定频道状态信息。本文提出了一个适用于完美、统计和表层化的CSIT情况的一般两阶段框架。拟议方法利用了BS的预码能力,从而能够有效地将特定Ues作为D中继器,向其余的UIS,并在设置的发射机组(CIT)设置中,并最大限度地将最差的多式SE-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-S-S-C-C-C-C-C-制式制式制式制式制式制式制式制式制式制式制式制式制式制式制式制式制式制式制压下最重制式制下最重制最大结果。

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