一种无线局域网DCF扩展算法——ExDCF

Extension to DCF for wireless local area networks——ExDCF

在基于IEEE802.11的无线局域网(WLAN)中,所有节点只能和接入点(AP)直接通信,即使在直接通信范围内的无线节点,其相互通信也要通过接入点进行转发,从而导致无线局域网的吞吐率大大降低。针对这一问题,提出一种分布协调功能(DCF)扩展算法——ExDCF算法:当两个通信节点在同一传输范围内时,两节点间的数据传输不需要接入点转发;即使两个节点不在一个通信范围内,两节点间数据传输需要接入点转发,但是接入点不需要再次竞争信道。该算法可以将节点间的吞吐率至少提高2倍。理论分析和仿真结果表明该算法能有效地提高无线网络的整体性能,并且能够与标准DCF很好地兼容。

In typical installation of an 802.11 based Wireless Local Area Network （ WLAN）, mobile hosts would access the network through Access Points （ AP）. Since the communication link between two mobile stations in the same WLAN effectively becomes a two-hop path, even if they can hear each other, the throughput degrades significantly. In this paper, ExDCF protocol as an extension to standard Distributed Coordination Function （DCF） protocol in WLAN was proposed, which could improve the throughput between two mobile stations more than twice. In ExDCF, when two mobile nodes are in the same transmission range, the data packets will be sent directly by the source to the destination without AP. Reversely, the data packets need forwarding by AP. However, AP can relay them without contention of the channel. Theoretical analysis and simulation results show that our ExDCF works better in WLAN than the standard DCF while remaining compatible to the standard DCF.