Investigation of the IEEE 802.11 medium access control (MAC) sublayer functions

Analysis of the draft IEEE 802.11 wireless local area network (WLAN) standard is needed to characterize the expected performance of the standard´s ad hoc and infrastructure networks. The performance of the medium access control (MAC) sublayer, which consists of distributed coordination function (DCF) and point coordination function (PCF), is determined by simulating asynchronous data traffic in a 1 Mbps ad hoc network, and asynchronous data and packetized voice traffic in a 1 Mbps infrastructure network. The simulation models incorporate the effect of burst errors, packet size, RTS threshold and fragmentation threshold on network throughput and delay. The results show that the IEEE 802.11 WLAN can achieve a reasonably high efficiency when the medium is almost error-free, but may degrade appreciably under harsh fading. The results also show that time-sensitive traffic such as packet voice can be supported together with other intensive traffic such as packet data. However, an echo canceller is required for packet voice systems