VoWLAN中QoS延迟性能分析与改进

VoWLAN（VoIP over WLAN）技术是一种利用无线局域网（WLAN）来传输VoIP帧的技术。VoWLAN中的语音业务是对延时较为敏感的实时业务，因此对其作延迟分析尤为重要。重点介绍了VoWLAN系统中AP节点处延迟产生过程，并采用一种新的具有优先级的M/G/1排队分析模型对AP节点处的延迟进行详细分析，该模型比以往所采用的单一的基于泊松过程的分析模型更精确；探讨了减少延迟的方法，提出新的点协调功能（PCF）方式下站点轮询算法，该算法可以更好的支持VoWLAN系统的VoIP等实时业务；最后用OPNET仿真工具进行了验证。

Analysis and improvement of the Qos delay performance in VoWLAN

VoIP over Wireless LAN(VoWLAN) has become increasingly popular as a medium to connect portable devices to the network.Since voice packets are extremely delay sensitive,it is important to characterize the delay properties occur in a VoWLAN network.The multimedia packets access delay incurred was analyzed in the Access Point(AP) based on a prioritized M/G/1 analysis model,which was more accurate than the classical single Poisson-based model to calculate the mean multimedia packets access delay incurred in AP.Then an improved Point Coordination Function(PCF) polling-scheduling algorithm was developed for improving the WLAN's multimedia traffic application by reducing the access delay.Finally,simulation results based on OPNET were presented to show the effect of this method on WLAN's multimedia traffic application like VoIP,etc.