The envisioned wireless networks of the future entail the provisioning of massive numbers of connections, heterogeneous data traffic, ultra-high spectral efficiency, and low latency services. This vision is spurring research activities focused on defining a next generation multiple access (NGMA) protocol that can accommodate massive numbers of users in different resource blocks, thereby, achieving higher spectral efficiency and increased connectivity compared to conventional multiple access schemes. In this article, we present a multiple access scheme for NGMA in wireless communication systems assisted by multiple reconfigurable intelligent surfaces (RISs). In this regard, considering the practical scenario of static users operating together with mobile ones, we first study the interplay of the design of NGMA schemes and RIS phase configuration in terms of efficiency and complexity. Based on this, we then propose a multiple access framework for RIS-assisted communication systems, and we also design a medium access control (MAC) protocol incorporating RISs. In addition, we give a detailed performance analysis of the designed RIS-assisted MAC protocol. Our extensive simulation results demonstrate that the proposed MAC design outperforms the benchmarks in terms of system throughput and access fairness, and also reveal a trade-off relationship between the system throughput and fairness.

翻译：未来无线网络的设计愿景包括提供海量连接、异构数据业务、超高频谱效率和低时延服务。这一目标正推动着针对下一代多址接入（NGMA）协议的研究，该协议能够在不同资源块中容纳海量用户，相较于传统多址方案实现更高的频谱效率和更强的连接能力。本文提出了一种适用于多可重构智能表面（RIS）辅助无线通信系统的NGMA多址接入方案。基于此，我们首先考虑静态用户与移动用户共存的实用场景，研究了NGMA方案设计与RIS相位配置在效率和复杂度方面的相互作用关系。在此基础上，我们进一步提出了RIS辅助通信系统的多址接入框架，并设计了融合RIS的媒体接入控制（MAC）协议。此外，我们对所设计的RIS辅助MAC协议进行了详细的性能分析。大量仿真结果表明，所提出的MAC设计方案在系统吞吐量和接入公平性方面均优于基准方案，同时揭示了系统吞吐量与公平性之间的权衡关系。