无线自组织网络可靠组播MAC协议

为了在无线自组织网络的MAC层中更好地提供可靠组播,在尽量少修改IEEE 802.11协议的原则下提出了一个可靠组播MAC协议RMMP(reliable multicast MAC protocol).首先由源节点组播RRTS(reliable RTS)帧,各接收节点依次回复RCTS(reliable CTS)帧;源节点在收到所有RCTS后,组播N个RDATA(reliable DATA)帧,各接收节点收到第N个要求回复的RDATA帧后依次回复RACK(reliable ACK)帧,然后源节点重传丢失帧.RMMP协议提高了MAC层组播可靠性.最后运用NS-2仿真软件对该协议进行验证,结果表明,RMMP在包投递率、吞吐量性能上都有很大的提高,实现了MAC层可靠组播,其代价是平均端到端时延略大.

Reliable MAC layer multicast protocol in wireless Ad Hoc networks

In order to provide MAC(medium access control) layer reliable multicast in wireless Ad Hoc networks,a new reliable multicast MAC protocol(RMMP) based on IEEE 802.11 is proposed.In this protocol,a sender multicasts a reliable RTS(RRTS) frame and the receivers reply with reliable CTS(RCTS) frames according to the designated sequence.Then the sender sends N reliable DATA(RDATA) frames and the receivers reply with reliable ACK(RACK) frames sequentially after receiving the N-th RDATA frame in which an acknowledgement frame RACK is demanded.The sender then retransmits the lost frames which are indicated in the RACK frame.The network simulator NS-2 was used to simulate to demonstrate the performance of the protocol.The results show that this protocol achieves reliable multicast at MAC layer by providing higher packet delivery ratio and throughput while slightly increasing average end-to-end delay.