A priority control method for wireless multi-hop access using IEEE 802.11 DCF mechanism

Multi-hop communication systems have been widely studied and many of them are based on the IEEE 802.11 WLAN system. This paper explains the problem of throughput degradation of a relay station when IEEE 802.11 DCF is adopted in multi-hop communications. The relay stations loose some of their capacity compared to the stations that are not relaying data of other stations. Because all stations, under the CSMA/CA protocol, will have equal transmission opportunity, the relay stations have to send packets from other terminals. In this paper, we propose an autonomous priority control method that changes the contention window size depending on the number of relay stations and the number of hops to ensure that relay stations are offered the same transmission capacity as regular stations in the service area. Then its performance is evaluated by computer simulations.