Kim Junbeom, Park Seok-Hwan
Division of Electronic Engineering, Jeonbuk National University, Jeonju 54896, Korea.
Entropy (Basel). 2020 May 15;22(5):554. doi: 10.3390/e22050554.
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.
尽管降低系统成本和提高频谱效率有潜在益处，但由于有限容量前传链路和簇间干扰信号导致的性能下降，实现云无线接入网络（C-RAN）系统具有挑战性。这项工作研究了两簇C-RAN系统上行链路的簇间协作接收，其中两个相邻簇在上行接入信道上相互干扰。两簇的无线单元（RU）通过有限容量前传链路将上行接收信号的量化和压缩版本转发到服务基带处理单元（BBU）。簇的BBU通过有限容量回程链路交换接收到的前传信号，以减轻簇间干扰信号。传统协作方案的优化，即每个RU产生单个量化信号，需要对与RU数量呈指数增长的搜索空间进行穷举离散搜索。为解决此问题，我们提出一种基于分层压缩的改进型BBU间（即簇间）协作策略，其中每个RU产生两个描述，只有一个描述通过回程链路转发到相邻BBU。我们讨论了所提出的簇间协作方案的优化，并通过数值结果验证了该方案的性能增益。
