高铁场景下基于缓存的无线云接入预下载机制研究

Research on Pre-downloading Mechanism of Cache-Based Wireless Cloud Radio Access in HSR Scenarios

云接入网(Cloud Radio Access Network,C-RAN)中有限带宽的前程链路无法有效应对高铁场景下乘客大量集中式的网络资源请求.针对这一不足,本文对C-RAN架构中的射频拉远头(Remote Radio Head,RRH)配置缓存设备使其具有存储转发资源的功能,利用列车运行信息可预知的先验条件,针对乘客数据通信提出基于缓存机制的预下载方案以提升网络系统的吞吐量.仿真结果表明,在前程链路拥挤情况下,基于缓存的预下载方案可明显提升资源的平均传输速率和高铁通信网络的吞吐量,进而提升了乘客的在途通信服务质量(Quality of Service,QoS).

The cloud radio access network(C-RAN)with limited-capacity fronthauls cannot cope with the large-scale centralized passenger resource requests efficiently in high-speed railway(HSR)scenarios.As such,this paper adds a cache device to the remote radio head(RRH)to enable the function of storing and forwarding resources.Moreover,a cache-based pre-downloading scheme for passenger data communication is proposed to improve the network throughput by using the predictive information of the train.The simulation results show that the proposed scheme can significantly boost the average transmission rate of resources,enhance the throughput of HSR communication network and improve passengers’in-journey communication quality of service(QoS)when the fronthaul link is congested.