车辆自组织网络中新型NP-CSMA随机多址协议研究分析

智能交通的出现使得车辆自组织网络受到越来越多的关注。车辆自组织网络的动态拓扑结构变化非常剧烈,这对网络的吞吐率、传输速率等性能提出了很高的要求。提出1种具有握手机制协议的自适应多通道双时钟NP-CSMA随机多址接入协议。该协议首先区分2种P-CSMA协议,握手机制成功解决了隐藏的终端问题,双时钟机制减少了平均空闲时间,多通道机制增加通道数量和划分用户优先级的同时提高了系统吞吐率,自适应机制能够使系统在高负载下保持稳定吞吐率。还对该协议的传输速率进行了分析,得出该协议的传输速率相对较高的结论。通过平均周期方法推导吞吐率和传输速率的计算公式,仿真结果与理论推导一致。

A new NP-CSMA random multipleaccess protocol based on VANETs

With the emergence of intelligent transportation, VANETs have received more and more attention. The dynamic topological structure of VANETs changes sharply, which makes high demands on network performance, such as the throughput rate and transmission rate. We propose an adaptive multi channel dual clock NP CSMA random multiple access protocol with RTS/CTS mechanism. We first define two kinds of P CSMA protocols. The RTS/CTS mechanism solves the hidden terminal problem, the dual clock mechanism reduces average idle time, and the multi channel mechanism increases channel number, identifies priorities of users and improves the throughput rate. The adaptive mechanism enables the system to maintain stable throughput rate under high load. We also analyze transmission rate, which is proved to be relatively high. The calculation formulas of throughput rate and transmission rate are derived through the average period method, and the simulation results are consistent with the theoretical derivation.