With the stringent requirements of fifth-generation and beyond wireless communications technology coupled with the potential bottleneck in the optical fronthaul, radio-over-fiber (RoF) technology offers an alternative solution to distribute the wireless signals while meeting these requirements. The inherent centralized architecture of RoF enables advanced coordination functionality to be performed within the fronthaul network. Advanced coordination functionality such as non-orthogonal multiple access (NOMA) has gained traction as a means to improve spectral efficiency for larger user-base networks. Among various NOMA implementations, the recently proposed multilevel code (MLC) was found to be superior to the commonly investigated superposition coding successive interference cancellation scheme in a two-user scenario. In this paper, we generalize the definition of the MLC to $n$n user cases and discuss two power allocation schemes for the generalized MLC definition, which are based on the spectral efficiency (SE) criterion and symbol error rate (SER) criterion, respectively. Simulation-based performance analysis on the MLC–SE and the MLC–SER schemes was conducted over different cluster sizes and randomly generated user distributions. The results show, to the best of our knowledge, that the best performance in terms of user fairness and bit error rate can be obtained in a two-user MLC–SER scheme.

中文翻译：

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基于多级代码的集群对非正交多路访问对光纤无线前传应用的影响研究

随着第五代及以后的无线通信技术的严格要求以及光学前传的潜在瓶颈，光纤无线（RoF）技术提供了一种在满足这些要求的同时分配无线信号的替代解决方案。RoF固有的集中式体系结构使高级协调功能可以在前传网络中执行。诸如非正交多路访问（NOMA）之类的高级协调功能已作为一种为大型用户基础网络提高频谱效率的手段而受到关注。在各种NOMA实现中，发现在两个用户的情况下，最近提出的多级代码（MLC）优于通常研究的叠加编码连续干扰消除方案。在本文中，我们将MLC的定义概括为$ n $ n个用户案例，并讨论了两种用于广义MLC定义的功率分配方案，它们分别基于频谱效率（SE）准则和符号错误率（SER）准则。在不同的群集大小和随机生成的用户分布上，对MLC-SE和MLC-SER方案进行了基于仿真的性能分析。结果表明，就我们所知，在两个用户的MLC-SER方案中，可以获得最佳的用户公平性和误码率性能。在不同的群集大小和随机生成的用户分布上，对MLC-SE和MLC-SER方案进行了基于仿真的性能分析。结果表明，就我们所知，在两个用户的MLC-SER方案中，可以获得最佳的用户公平性和误码率性能。在不同的群集大小和随机生成的用户分布上，对MLC-SE和MLC-SER方案进行了基于仿真的性能分析。结果表明，就我们所知，在两个用户的MLC-SER方案中，可以获得最佳的用户公平性和误码率性能。