Cooperative Resource Management in Cognitive WiMAX with Femto Cells

WiMAX with femto cells is a cost-effective next generation broadband wireless communication system. Cognitive Radio (CR) has recently emerged as a promising technology to improve spectrum utilization by allowing dynamic spectrum access. There will be large potential benefits by applying the CR technique to WiMAX with femto cells, which are barely explored in the literature. In this paper, we propose a novel cognitive WiMAX architecture with femto cells, where the base station and users are equipped with CRs and intelligently adjusts power, channel, and other resources to accommodate the entire network ecosystem. In this new design, we develop an optimization framework for location-aware cooperative resource management, by jointly employing multi-hop cooperative communication, power control, channel assignment, primary user protection, buffer management, and fairness, and incorporating user, channel, and cooperative diversities. To achieve optimality, it is designed based on stochastic Lyapunov optimization, aiming to take advantage of the radio flexibility and fully utilize the spectrum. Evaluated by the rigorous analysis and extensive simulations, our resource management protocol is near-optimal with closed-form bounds, with which cognitive WiMAX achieves substantial performance improvement.