MIMO链路ad hoc网络中一种新的MAC协议

Novel MAC protocol for MIMO link ad hoc networks

针对支持MI MO的并行RTS处理(PRP)MAC中分组的冲突导致网络通过量减小的问题,提出了基于五阶段预约的改进MAC协议(FPR-PRP MAC).该协议采用同步的时间结构,通过五阶段预约使网络节点获得传输时隙号.在信息时隙,根据预约的结果,一部分节点可以优先发送RTS分组,其他节点再通过竞争发送RTS分组.接收节点根据收到的全部RTS决定允许各发送节点使用的数据流数目,并将此允许值携带在CTS中回复给发送节点.FPR-PRP MAC将预约与竞争相结合的机制减少了网络中RTS冲突,同步的时间结构消除了控制分组和数据分组的冲突,因此可以有效地改善网络性能.仿真结果表明,在网络比较繁忙的情况下,与PRP MAC相比,FPR-PRP MAC可以大幅增加网络中流控方式发送的分组数,并提高网络的通过量.

Considering the throughput reduction caused by the packet collision of the PRP MAC, a novel MAC based on five phase reservation （FPR-PRP MAC） is proposed. The FPR-PRP MAC adopts a synchronous time structure, and it allows the nodes in the network to acquire transmission slot numbers through five phase reservation. Then in information slots, some nodes can transmit RTS packets with higher priority according to the reservation results, and other nodes contend with each other to transmit RTS packets. A receiving node determines the maximum allowable number of data streams according to all the RTS packets it has received, and put this number in the CTS packet to reply to the transmitter. The mechanism of combining reservation with contention in FPR-PRP MAC reduces the collisions of RTS packets in the network. Moreover, the synchronous time structure in FPR-PRP MAC eliminates the collisions of the control packet with the data packet. Therefore, the proposed FPR-PRP MAC can improve the performance of the network effectively. Simulation results show that, in a heavy load situation, compared with the PRP MAC, the FPR-PRP MAC can transmit many more packets in a stream-controlled way, and increase the network throughput.