Cloud radio access network (C-RAN) is an important architecture for 5G networks. In C-RAN systems, baseband units (BBUs) are centralized in a BBU pool and remote radio heads (RRHs) are connected with the BBU pool through front-haul links. The BBU-RRH peer switching scheme is quite a key point in C-RAN especially for fast switching scenarios. A typical C-RAN system based on software defined radio (SDR) and virtual machine migration is introduced as the system model. Then we analyze the factors, including packet delay, and power consumption, that influence the performance of a C-RAN system. We conclude backlogs, idle computation resources, and switching costs could reflect the system performance adequately. They can evaluate radio resource usage, computation resource usage, and extra computation resource usage, respectively. Based on the evaluation model, the optimization algorithm is studied. In this paper, we propose a method to find the optimized load range for the BBUs. Taking switching quality into consideration, we propose a scheme that can adjust the BBU working load dynamically in an optimized range with less switching cost. The system performance variation under different switching intervals is also investigated. Finally, the effectiveness of the proposed optimization scheme is validated by simulation results.

中文翻译：

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在5G云无线电接入网络中通过VM迁移实现快速切换

云无线电接入网络（C-RAN）是5G网络的重要架构。在C-RAN系统中，基带单元（BBU）集中在BBU池中，而远程无线电头（RRH）通过前传链路与BBU池连接。BBU-RRH对等交换方案是C-RAN中的关键点，特别是对于快速交换方案而言。介绍了一种基于软件定义无线电（SDR）和虚拟机迁移的典型C-RAN系统作为系统模型。然后，我们分析影响C-RAN系统性能的因素，包括数据包延迟和功耗。我们得出的结论是，积压，空闲的计算资源和切换成本可以充分反映系统性能。他们可以分别评估无线电资源使用情况，计算资源使用情况和额外的计算资源使用情况。基于评估模型，研究了优化算法。在本文中，我们提出一种方法来找到BBU的最佳负载范围。考虑到交换质量，我们提出了一种方案，该方案可以在优化范围内动态调整BBU工作负载，并且交换成本较低。还研究了在不同切换间隔下的系统性能变化。最后，仿真结果验证了所提优化方案的有效性。还研究了在不同切换间隔下的系统性能变化。最后，仿真结果验证了所提优化方案的有效性。还研究了在不同切换间隔下的系统性能变化。最后，仿真结果验证了所提优化方案的有效性。