Interference Management in Shared Spectrum for WiMAX Systems

Spectrum sharing methods, such as secondary spectrum access, are powerful candidates to improve spectrum utilization and efficiency. In this paper, we develop a novel resource allocation scheme for WiMAX networks, which is designed to maximize performance while limiting the received interference at each user. By defining different interference tolerances for different sets of users, the proposed allocation scheme can be exploited in a secondary spectrum access scenario where two WiMAX operators, one as the primary operator and the other one as the secondary operator, are using a shared band. The primary system benefits either by charging the secondary system for the use of its resources, or by some form of reciprocal arrangement allowing it to use the secondary system´s licensed bands when needed. Numerical results show our resource allocation approach to achieve an excellent fairness, while incurring only a slight reduction in system throughput compared with the theoretical upper limit of opportunistic scheduling.