Queueing Analysis of OFDM Subcarrier Allocation in Wireless Multimedia Networks

There are two major contributions in this paper in the context of Orthogonal Frequency Division Multiplexing (OFDM) subcarrier allocation. The first is to perform a tele- traffic queueing analysis for OFDM subcarrier allocation in wireless multimedia networks. In the literature, a variety of issues related to OFDM have been studied. However, the OFDM system performance is rarely investigated. Call connection requests are differentiated into two types: narrow-band and wide-band. For either class of call, the traffic process is characterized as batch arrival because each call may request multiple subcarriers to satisfy its Quality-of-Service (QoS) requirements. The batch size is a random variable following a probability mass function (pmf) with a realistic maximum value. In addition, the service times for various classes are different. Consequently, in OFDM- based broadband wireless multimedia networks, the system are formulated as multiclass multiserver batch arrival queueing systems. The second contribution is the investigation of two call admission control algorithms, the batch blocking scheme and the partial blocking scheme. Formulae are developed for the following significant performance metrics: the probability that a call will be blocked and bandwidth utilization. Numerical investigations are presented to demonstrate the key interaction between key parameters and performance metrics. The analytical model was validated by the simulation results; consequently, it provides an efficient tool for building future-generation broadband wireless access networks.