Buffer management for WiMax/802.16 subscriber stations

Quality of service (QoS) is a critical feature of WiMax/802.16. It guarantees a certain level of performance (bandwidth and delay) to a service flow in accordance with traffic contract parameters. WiMax/802.16 QoS guarantees are achieved by multiple management modules: base station (BS) scheduler, BS buffer manager, subscriber station (SS) scheduler and SS buffer manager. In the previous work, the first three management modules have been addressed, but SS buffer management for outgoing traffic is not mentioned. A WiMax/802.16 system without a SS buffer management scheme for outgoing traffic cannot completely provide QoS guarantees to multiple kinds of WiMax/802.16 service flows. The topic of this research is buffer management for outgoing traffic in a WiMax/802.16 SS. The first goal is to minimize the packet-loss-rate for real-time traffic flows. The second goal is to lower the overall packet-loss-rate caused by a lack of buffer space. The third goal is to achieve a QoS guarantee. In this thesis, we propose a new buffer management scheme called admission control and dynamic buffer allocation (ACDB) for outgoing traffic in a WiMax/802.16 SS. It consists of two parts: an admission control (AC) algorithm and a dynamic buffer allocation (DBA) algorithm. Simulation results demonstrate that our proposed buffer management scheme achieve the above three goals and provide QoS guarantee for multiple types of service flows.