支持QoS的无线局域网自适应MAC协议算法

Wireless LAN adaptive MAC protocol algorithm with QoS support

针对增强分布式接入(EDCA)机制在高负载网络中竞争窗口变化过于陡峭,导致网络性能大幅度下降这一问题,提出了一种自适应退避算法。在GDCF算法的基础上,用数据包最大退避阶段的均值来衡量当前网络拥塞状况,进而动态调整竞争窗口的重置方式,降低网络冲突,提升网络性能。所提算法额外开销较少,易于工程实现,在NS—2中仿真实验结果表明:改进算法能够显著提升EDCA机制在高负载网络下的性能,降低高优先级业务时延,提高各优先级业务吞吐量。

Aiming at the problem that the contention window of enhanced distributed channel access(EDCA)mechanism changes too steeply in high-load network,leading to a significant performance degradation of network,an adaptive backoff algorithm is proposed.On the basis of GDCF algorithm,the current network congestion status is measured by the mean value of the maximum backoff phase of the data packet,thus dynamically adjust the reset method of contention window.Such approach can reduce network collisions and improve network performance.The algorithm has less extra cost and is easy to be implemented,the simulation in NS—2 shows that the improved algorithm can significantly improve the performance of the EDCA mechanism in high-load network,reduce the delay of high-priority service,and improve the throughput of each priority service.