基于网络编码的车联网商业应用时延控制方案

Controlling delay scheme for VANETs business application based on network coding

网络编码被认为是改善网络性能的新兴技术。在车联网VANETs中,带宽被认为是最重要的网络资源。为此,利用网络编码技术提高VANETs中非安全应用的带宽利用率。当两个源节点同时向同一区域广播数据时,转发节点(Relay)就利用网络编码技术降低重播次数和带宽消耗。当转发节点Relay接收到数据包时,它有两个选择:等待编码机会,节省带宽;或直接发送数据包,降低时延。针对这两个选择,提出了两个不同的时延控制方案,分别命名为缓冲区域控制方案BSCS和时间控制方案TCS,用于降低数据包每一跳的时延和提高带宽利用率。仿真结果表明,两个方案能较好地控制时延,且带宽利用率提高了38%。

Network coding is an emerging technique known to improve the network performance in many aspects. In Vehicular Ad-hoc Networks（ VANET）, the bandwidth is considered to be one of the most important network resources. This paper proposes a net-work coding technique to improve the bandwidth utilization for non- safety applications in VANET. In a scenario where there are two sources broadcasting the data into the same area at the same time, the relay will use the network coding technique to decrease the number of rebroadcasting events and the consumption of the bandwidth. However, a fundamental problem for the relay when it receives a packet, is whether to wait for a coding opportunity and save the bandwidth or send the packet directly and reduce the delay. In order to address such tradeoff, we introduce two versions of our protocol, named buffer size control scheme（BSCS） and time control scheme（ TCS）. By both versions we aim to control the delay that is experienced by the packet at each hop, while achieving better bandwidth utilization. Up to 38 % improvement in the bandwidth utilization has been recorded, and both schemes have shown a considerable amount of control on the imposed delay.