Comparative Study of the IEEE 802.16 Random Access Mechanisms

The WiMAX technology based on the IEEE802.16 standard is currently the most prospective candidate for broadband wireless access networks. One of the key issues is the design of the MAC layer, in particular the multiple access scheme. The IEEE 802.16 standard specifies different scheduling services with individual mechanisms for accessing the channel on the uplink. The non-real-time polling service and the best-effort service mainly rely on a contention mechanism to submit bandwidth requests to the base station. These two services are currently used for all types of traffic with unknown characteristics, i.e. typically all traffic except for some special VoIP connection with known codec. In this paper, we evaluate and compare the performance of the contention mechanisms for fixed and mobile WiMAX.