A Distributed Approach to Interference Mitigation Between OFDM-Based 802.16 Systems Operating in License-Exempt Spectrum

An approach to mitigating interference between 802.16 license-exempt systems is proposed in this paper. More specifically, the approach focuses on solving problems which arise when two or more 802.16 systems operate on the same channel in close proximity to each other. The essence of the approach is a distributed mechanism which can apportion the available OFDM subcarriers between the different 802.16 systems. Simulation results show that the topology and the distributions of base stations (BSs) and the subscriber stations (SSs) have a significant impact on the system performance. Also, the system is very sensitive to the order in which the different nodes in the system are activated. Furthermore, the system with the given parameters can operate satisfactorily for up to 6 BSs in the same area, but scalability problems arise if more BSs are added.