Improving QoS for BE traffics in WIMAX networks

WIMAX networks are aim to provide services with high throughput (up to 70 Mbps) and with a large coverage (up to 50 Km) To ensure QoS architecture has been designed and in the IEEE 802.16.e amendment they introduce the service differentiation by 4 service classes (UGS, rtPS, nrtPS and BE). Add to this an Admission control (AC) has been specified to avoid any degradation of the active connection. This mechanism is not defined in the literature and is let to the operators. Major implemented AC use the strict priority. The drawback of the strict priority is that it penalizes service classes with the lowest priority especially the BE. In this paper we propose to improve the AC of BE in WIMAX networks. To achieve this goal we propose to use the leaky bucket for both rtPS an nrtPS in order to reduce lightly the number of accepted connections and to improve considerably the number of BE accepted connection. We evaluate the performance of the proposed scheme by a markovian model.