车载网络中提高公平性的数据包大小自适应调节方案

双向路的车载网络中,两个方向上的数据流在竞争信道时存在严重的不公平现象,使得网络性能急剧下降.针对这种不公平问题,本文经理论分析得出数据包大小Packet与相向行驶车辆间的相对速度V、数据流接入信道几率P及数据流的平均吞吐率Throughput存在的函数关系,提出一种数据包大小自适应调节方案.模拟仿真表明,该方案有效的提高了信道竞争的公平性并能够保证每条数据流相对较高的平均吞吐率.而后本文定义了"SRTS/SCTS"并给出了车辆间相对速度V的获取过程.

An Adaptive Packet-Size Adjusting Scheme for Improving Fairness in Vehicle Networks

Data streams in two sides of a two-way road endure severe unfairness problem due to the competition of holding channel resource among neighbor vehicles,which leads to very low network performance.In order to solve this problem,the relationship between the packet size and relative velocity of each way's vehicles,and the effect of packet size on the probability of successfully competing for the wireless channel as well as the throughput of each data stream are analyzed in this paper.Based on the analysis,an adaptive packet-size adjusting scheme is proposed to improve the fairness of vehicle networks.The simulation results show that the fairness of competing for the channel has been improved greatly and the throughput of each stream is kept relatively high by this scheme.Finally,the "SRTS/SCTS" is defined and the procedure of obtaining the relative velocity is given.