移动WiMAX网络中的VoIP调度机制

移动微波存取全球互通(WiMAX)网络使用了5种调度机制来保证服务质量,其中的3种被设计用于实时性业务。但是,这3种调度机制都缺乏公平性。在资源不足的时候,通过丢弃新用户的请求来保证旧用户的服务质量(QoS)。为此,针对WiMAX中的因特网语音(VoIP)服务提出了一种基于优先权的新调度机制。该机制中,不同用户的业务请求将被赋予不同的优先权。新旧用户同时请求资源时,新用户的请求拥有更高的优先权;资源分配中心再根据优先权的高低为用户分配资源,从而在最大限度上保证了资源分配的公平性。仿真结果显示,新调度机制可以将网络中的因特网语音服务的连接数和总吞吐量分别提高15%和11%左右。

Scheduling mechanisms for VoIP in mobile WiMAX networks

Five scheduling mechanisms have been proposed to ensure Quality of Service (QoS) in WiMAX network. Three of them are designed for real-time applications. However, fairness has not been considered while assigning resources in these scheduling mechanisms. In order to guarantee the existing services, new service requests will be rejected when lacking network resources. For resolving this problem, a new scheduling mechanism was proposed for Voice over Internet Protocol (VoIP) service, in which a Priority Decision Maker (PDM) was implanted. When new services and the existing services requested resources simultaneously, higher priority would be assigned to new service requests; and resource allocation would be achieved based on different level priorities by a resource distribution center for guaranteeing fairness. Detailed performance analysis was performed. The simulation results show the proposed scheduling mechanism could significantly increase number of VoIP connections and total throughput, about 15% and 11% respectively.