系统分别对无线通信中的几种重要的多址接入协议进行了仿真，包括pure-ALOHA,slotted-ALOHA,CSMA以及ISMA，对每种协议的信噪比-误码率关系进行了分析。-Of wireless communications systems are in several important multiple access protocol simulation, including the pure-ALOHA, slotted-ALOHA, CSMA and ISMA, signal to noise ratio of each type of agreement- the relationship between bit error rate are analyzed.