Despite the potential benefits of reducing system costs and improving spectral efficiency, it is challenging to implement cloud radio access network (C-RAN) systems due to the performance degradation caused by finite-capacity fronthaul links and inter-cluster interference signals. This work studies inter-cluster cooperative reception for the uplink of a two-cluster C-RAN system, where two nearby clusters interfere with each other on the uplink access channel. The radio units (RUs) of two clusters forward quantized and compressed version of the uplink received signals to the serving baseband processing units (BBUs) via finite-capacity fronthaul links. The BBUs of the clusters exchange the received fronthaul signals via finite-capacity backhaul links with the purpose of mitigating inter-cluster interference signals. Optimization of conventional cooperation scheme, in which each RU produces a single quantized signal, requires an exhaustive discrete search of exponentially increasing search size with respect to the number of RUs. To resolve this issue, we propose an improved inter-BBU, or inter-cluster, cooperation strategy based on layered compression, where each RU produces two descriptions, of which only one description is forwarded to the neighboring BBU on the backhaul links. We discuss the optimization of the proposed inter-cluster cooperation scheme, and validate the performance gains of the proposed scheme via numerical results.

中文翻译：

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存在集群间干扰的回程约束 C-RAN 上行链路系统的分层集群间协作方案

尽管降低系统成本和提高频谱效率具有潜在的好处，但由于有限容量的前传链路和集群间干扰信号导致性能下降，因此实施云无线接入网络 (C-RAN) 系统具有挑战性。这项工作研究了双集群 C-RAN 系统上行链路的集群间协作接收，其中两个相邻的集群在上行链路接入信道上相互干扰。两个集群的无线电单元 (RU) 通过有限容量的前传链路将上行链路接收信号的量化和压缩版本转发到服务基带处理单元 (BBU)。集群的 BBU 通过有限容量的回程链路交换接收到的前传信号，目的是减轻集群间的干扰信号。传统协作方案的优化，其中每个 RU 产生单个量化信号，需要详尽的离散搜索，搜索大小相对于 RU 的数量呈指数增长。为了解决这个问题，我们提出了一种基于分层压缩的改进的 BBU 间或集群间协作策略，其中每个 RU 产生两个描述，其中只有一个描述被转发到回程链路上的相邻 BBU。我们讨论了所提出的集群间合作方案的优化，并通过数值结果验证了所提出方案的性能提升。我们提出了一种基于分层压缩的改进的 BBU 间或集群间协作策略，其中每个 RU 产生两个描述，其中只有一个描述被转发到回程链路上的相邻 BBU。我们讨论了所提出的集群间合作方案的优化，并通过数值结果验证了所提出方案的性能提升。我们提出了一种基于分层压缩的改进的 BBU 间或集群间协作策略，其中每个 RU 产生两个描述，其中只有一个描述转发到回程链路上的相邻 BBU。我们讨论了所提出的集群间合作方案的优化，并通过数值结果验证了所提出方案的性能提升。