Delay-Based Admission Control Using Fuzzy Logic for OFDMA Broadband Wireless Networks

In this paper, we present a fuzzy logic-based admission control algorithm for orthogonal frequency division multiple access (OFDMA)-based broadband wireless networks. The system under consideration is compatible with the IEEE 802.16 standard in the TDD-OFDMA mode of operation. The proposed admission control algorithm considers various traffic source parameters (i.e., normal rate, peak rate and probability of peak rate) and packet-level delay requirements for the traffic to decide whether an incoming connection can be accepted or not. We formulate a queueing model to investigate the impacts of physical layer parameters (e.g., channel quality and number of allocated subchannels) on the radio link layer performances (e. g., average queue length, delay and throughput). The inference rules for resource allocation in the proposed fuzzy logic admission control are defined based on these queueing performance measures. The performance of the proposed admission control algorithm is analyzed by simulations and also compared to those of the traditional schemes.