MIMO Ad Hoc网络中基于正交阵列的拓扑未知多址接入协议

摘要

An orthogonal array based topology transparent MAC(Media Access Control)protocol named MIMO -O -TTMA(MIMO Supported Orthogonal Array Based Topology Transparent Multiple Access)is proposed for MIMO(Multiple Input Multiple Output)Ad Hoc networks.The protocol utilizes the orthogonal arrays to assign slots for network nodes,in each assigned slot,the transmitters determine the number of streams to be used by exchanging the RTS/CTS (Request To Send/Clear To Send)packets with their destination nodes,in this way,the nodes can opportunistically use the spatial multi-plexing(SM)of MIMO to enhance the network performances.In addition to ensuring at least one collision-free slot in a frame for each node,the MIMO -O -TTMA allows the frame length to be flexibly chosen in certain range,which provides favorable conditions for optimizing the protocol performances.To evaluate the performance the MIMO -O -TTMA,a proba-bility method is used to analysis the throughput of the protocol.Numerical results show that,compared with the existing to-pology transparent MAC,MIMO -O -TTMA can effectively improves the network throughputs.%针对支持MIMO（Multiple Input Multiple Output）的Ad Hoc网络，提出了基于正交阵列的拓扑未知多址接入协议MIMO－O－TTMA（MIMO Supported Orthogonal Array Based Topology Transparent Multiple Access）．协议利用正交阵列为节点分配若干时隙，在每个分配时隙中，节点通过与目的节点交互RTS／CTS（Request To Send／Clear To Send）分组来确定发送的数据流数，以机会地利用MIMO的空间复接来提升网络性能．MIMO－O－TTMA在保证节点在一帧内至少有一个时隙能够无干扰地传输的基础上，允许协议的帧长能在一定的范围内进行灵活选择，从而为协议性能的优化提供了更为有利的条件．为评估MIMO－O－TTMA的性能，利用概率方法分析了协议的吞吐量性能，数值结果表明，与已有拓扑未知MAC（Media Access Control）相比，MIMO－O－TTMA有效提升了网络吞吐量．