Active Queue Management for Reducing Downlink Delays in WiMAX

In WiMAX networks, the base station (BS) is a likely bottleneck for downlink (DL) TCP connections due to difference in available bandwidth between the fixed network and the wireless link. This may result in buffer overflows or excessive delays at the BS, as these buffers are connection-specific. In order to avoid buffer overflows, different active queue management (AQM) methods may be applied at the BS. This paper presents an analysis of several AQM mechanisms and proves that they are indeed very useful: AQM reduces considerably DL delays at the WiMAX BS without sacrificing TCP goodput.