The same direction multi-hop downloading network flow model was proposed for vehicle communication range and channel competition under forwarding. According to the model and video streaming media characteristic, the same & opposite direction cooperative downloading quality of service (SODCD-QoS) scheme was presented. First, the same direction vehicles helped the target vehicle to achieve multi-hop cooperative downloading. It can reduce the waste of time which the target vehicle has to wait for opposite direction cooperative vehicle. Secondly, the next base stations loaded data into eligible opposite direction vehicles according to vehicles option strategy based on time first or picture quality first. Then the opposite direction vehicles helped the target vehicle to achieve one-hop cooperative downloading. NS simulations show that the SODCD-QoS scheme is better than DSRelay and VCoDS algorithm in terms of download time. Further, the new scheme can maintain good picture quality PSNR.%针对车辆通信范围及转发状态下信道竞争问题,建立了同向多跳下载流量模型.根据该模型与视频流媒体特点,提出了一种基于服务质量的双向协助下载方案.首先,同向车辆对目标车辆进行多跳协助下载,减少目标车辆等待对向协助车辆到达所消耗的时间.其次,后方基站根据时间优先或画质优先的选车策略,向符合条件的对向车辆加载数据,对向车辆与目标车辆相遇时进行一跳协助下载.NS 仿真表明,所提方案在下载耗时方面优于DSRelay 算法与VCoDS 算法,并能将画质参数PSNR 值维持在较好水平.
展开▼
