传统的分布式Ad hoc网络的单信道媒体接入控制(MAC)协议在同一时刻一跳范围内只能允许一对节点通信,导致网络的冲突严重、吞吐量小和接入时延较大.为此,文中利用MIMO系统的多包接收能力,设计了一种新的分布式Ad hoc网络MAC协议,该协议利用二进制退避和共享退避机制进行信道预约和共享,在单信道自由竞争的Ad hoc网络中实现了多点对点的通信,大幅度提高了网络吞吐量.文中还推导了该协议的网络归一化饱和吞吐量的数学模型.理论分析和仿真实验证明,新协议的网络吞吐量比利用分层空时编码(BLAST)的CSMA/CA(k)协议有了较大的提高.
As the traditional medium access control(MAC) protocols allow only one pair of nodes to communicate in a neighborhood of distributed single-channel Ad hoc networks,serious collision,low throughput and large delay may occur in this kind of network.In order to solve these problems,a novel MAC protocol based on the multi-packet reception(MPR) of multiple-input multiple-output(MIMO) system is proposed.In this protocol,both the binary-backoff and the share-backoff mechanisms are used to reserve and share the physical channels,thus realizing the multipoint-to-point communication in distributed single-channel Ad hoc networks and significantly improving the network throughput.A mathematical model of the normalized saturation throughput is also established for the new protocol.Theoretical and simulated results indicate that the proposed protocol outperforms the CSMA/CA(k) protocol based on the Bell Laboratories layered space-time(BLAST) coding in terms of network throughput.