网络拓扑MAC协议信道非均等抢占率优化模型

Optimization Design and Simulation of Channel Access Strategy Based on MAC Protocols

MAC协议采用的传统网络技术是将每个节点在信息传输过程中都看作目标节点,使每个这些基点拥有同等的信道访问机会。而对于访问方式为树状的无线传感器网络技术,均等的信道访问机会就会造成信道、信息能量等信息资源的浪费。针对MAC协议的CSMA/CA信道访问的信息传输方式与无线传感器网络技术的树状传输特点不能完全匹配问题,提出了一种网络拓扑的MAC协议信道优化模型。首先构建了传输层中每层的最小竞争窗口值来改变每个节点的信道抢占概率,将每个节点的均等信道访问方式变为信道的非均等访问方式,同时研究了节点最小竞争窗口值计算模型,给出了最小竞争窗口上限值,使信道访问方式达到与树状拓扑无线传感器网络的匹配,从信息丢包率及吞吐量等方面分析说明该优化提高了信道资源利用率。

The traditions network technical based on MAC protocol considered every node as the aim node, which make every node has the same chance on channel access. In wireless senor networks, we analyzed the conflict between Carrier Sense Multiple Access with Collision Avoidance （CAMA/CA） based MAC protocols and the tree structured transmission in wireless sensor networks. Based on the address of the transmission feature of wireless sensor networks, we proposed a MAC layer optimal algorithm. And the algorithm improves the equal channel access strategy in CAMA/CA and adjusts the channel access strategy based on the location of the nodes in the transmission tree to fit the transmission feature of wireless sensor networks, which enhance the network fairness. The objective of the algorithm is to improve MAC efficien- cy, including loss ratio, throughput. The performance on data loss ratio and the throughput of the algorithm are verified via the simulation results.