Performance evaluation of IEEE802.16 protocol using FDD allocation scheme

WiMAX is currently one of the hottest technologies for Broadband Wireless Access (BWA) systems which propose a wireless high-speed and high performance access system, with service differentiation for distinct classes of traffic and QoS requirements. IEEE802.16 standard specifies the PHY and MAC layers for BWA system and provides the flexibility of TDD and FDD allocation schemes. However, in spite of including the possibility of QoS support, the standard does not define how to schedule different types of traffic. In this paper, we apply a modified scheme, based on a Reservation Priority Access Control (RPAC), using FDD allocation approach. The behavior of this modified reservation scheme is evaluated with the inclusion of variable priorities among stations. An analytical model to evaluate the performance of the proposed scheme is also developed. The performance of the modified scheme is compared with TDD allocation scheme. We note that FDD allocation scheme gives superior results, with respect of message waiting-time.