Performance of the Ad-hoc IEEE 802.11b Wireless LAN

摘要

The performance of the IEEE 802.1lb Wireless LAN (WLAN) is evaluated under Distributed Coordination Function (DCF) ad-hoc topology. A number of stations with different types of applications are used in the tests. The evaluated application types are maximum rate data transfer, H.263 video streaming, and Voice over IP (VoIP). UDP/IP protocols are exploited on transport and network layers. The performance results are acquired by simulations using a Specification and Description Language (SDL) simulation model and by practical testing. The results indicate that the ad-hoc WLAN divides the available bandwidth nearly equally with contenting stations. The average achieved throughput remains predictable as the number of active stations increases. For application requiring constant bit rate, such as VoIP, the transfer delay variance becomes a challenge when aggregate traffic load is increased on WLAN. For enabling these demanding applications, modified ad-hoc contention algorithms for differentiating Quality of Service (QoS) according to the traffic type seem potential.