基于MATLAB的TDMA/CSMA混合协议仿真分析

摘要

TDMA and CSMA are two kinds of common multiple accesses protocols of Ad Hoc network,they have both advantages and disadvantages.TDMA can avoid collision among different nodes,but average delay becomes longer when network scale expands,at the same time,if some nodes don't have transmission requirement in its slots,there will be free slots.CSMA uses competition pattern,but collision probability of nodes increases when network scale expands.According to two kinds of protocols,this paper presents a kind of mixed multiple accesses protocol which combines TDMA with CSMA.Using fixed distribution and dynamic distribution to improve network efficiency and decrease average delay.Using MATLAB software to simulate and prove its property.%TDMA(时分多址)和CSMA(载波侦听)是两种常见的Ad Hoc网络多址接入方式,两种方法各有利弊.TDMA避免了节点之间的冲突,但是平均时延随着网络规模的扩大而急剧增长,当某节点在给定的时隙内没有发送请求时,会产生空时隙,造成资源浪费;CSMA采用竞争的方式,当网络规模扩大时,节点的碰撞概率很大,信道利用率降低.根据两者的特点,提出了TDMA/CSMA混合多址接入协议,采用固定分配和动态分配相结合的方式,进一步提高网络吞吐量、降低平均时延,并通过MATLAB软件对协议进行仿真建模,验证其性能.