Performance modelling of a distributed approach to interference mitigation in license-exempt IEEE 802.16 systems

In this paper, three approaches to modelling a distributed approach to interference mitigation in 802.16 license-exempt (LE) systems are described. An interference-free (IF) approach in which no interference is permitted at any node of the system; a controlled-interference (CI-T) and a controlled-interference with fairness (CI-F) approaches where interference is permitted at nodes that do not benefit from receiving the current transmission. The results show that the CI-F and CI-T schemes result in much better overall performance that either the IF scheme or the distributed scheme. Further, they result in much greater levels of BS activity. Despite being very conservative, even the IF scheme performs better than the distributed scheme in terms of throughput. This can be attributed to the fact that the distributed scheme suffers from collisions