Joint Physical – MAC Layer Resource Allocation Approach for Heterogeneous Traffics in OFDM

In this paper a novel cross layer resource allocation for downlink transmission with heterogeneous traffic in wireless networks is developed. The problem of efficient resource allocation for multiuser orthogonal frequency division multiplexing over Rayleigh fading channels is addressed. Subcarrier and power allocation are carried out sequentially to reduce the complexity. Assuming that the base station has all the channel information, an optimization problem for an adaptive sub-channel and power allocation scheme that maximizes weighted sum capacities of many traffic queues at the physical (PHY) layer while satisfying the required data rate of each user and the power constraint on each link is considered. The weights are determined using information from the medium access control (MAC) layer. Genetic algorithm, Particle Swarm Optimization and Ant Colony Optimization techniques are used to do subcarrier allocation. Simulation results show that the Hybrid PSO and ACO performance is better than GA in terms of system capacity, throughput and convergence.