基于双忙音的多址接入协议的研究

在Ad Hoc网络中．隐藏终端和暴露终端的存在严重影响了网络的通信能力。双忙音多址接入（DBTMA）协议是采用RTS／CTS对话机制来预约信道，通过引入两个窄带带外忙音信号来避免分组间冲突，解决了隐藏终端和暴露终端问题。本文在两个方面进一步对DBTMA进行改进：第一，使用一个控制分组RTS来预约信道，通过目的节点所发接收忙音来响应RTS分组；第二，采用时隙ALOHA协议对RTS分组进行传输，通过改进，提高了控制分组成功传输的概率，经仿真研究分析表明，提高了网络的吞吐量，增强了网络性能。

Research of Multiple Access Protocol with Dual Busy Tone

In Ad Hoc networks,the hidden and exposed terminal problems can severely reduce the network capacity on the MAC layer.The operation of Dual Busy Tone Multiple Access(DBTMA) is based on the RTS/CTS packet and two narrow bandwidth,outofband busy tones.The RTS/CTS dialogue is used to reserve the channel.In addition,two narrow bandwidth,outofCD*band busy tones are employed to eliminate collisions between the RTS/CTS control packet and DATA packet transmissions,the scheme solves the hidden and the exposed terminal problems.In improved DBTMA,the RTS packet is acknowledged by the receive busy tone,and the RTS packet is transmitted in slotted ALOHA scheme instead of pure ALHOA scheme,which improves the probability of successful RTS reception.The result of simulation shows that improved DBTMA scheme increases the throughput and improves the performance.