The Research On Call Blocking Performance Of Wireless System Traffic Model

In the modern network communication system, the quality of service (QoS) of each user becomes more important according to the increase of the bearer services of network. Call blocking probability is very important to determine the QoS of each user. The research of the network model is also the important precondition to guarantee QoS.Many measurements from the work packet networks have been collected and analyzed during the past several years. These studies proved that traditional models neglected an important characteristic—self-similarity. The characteristic of traffic has a great effect on the analysis, design, control, and performance evaluation of computer networks. The formula of Erlang B is speculated to hold for any M/G/C/C system with general service time distribution, but rigorous proof is absent. In this thesis, several mathematical definitions of self-similarity are given; some of their features are described. The simulation of M/P/C/C queuing system has been researched, especially considering the situation that the number of servers is huge. We use a kind of data structure named red-black tree to solve the time-consuming problem caused by overlong sequence and huge number of servers C. And event-driven time scheduling simulation method is adopted. The simulation result coincides well with Erlang B formula. This lays the foundation of further research on using simulation methods to study the performance of self-similarity network traffic.It is demanded to support the broadband multimedia service in 3rd Generation (3G), such as voice, video, and data. In wireless systems, according to the increase of mobile users, it is more and more important that avoiding network congestion, decreasing voice losing and guaranteeing the QoS. In integrated service systems, it's quite crucial to get the new call and handover call blocking probability quickly and accurately under the Real-time Call Admission Control,when such parameters as the number of cell channels, the number of guard channels and both new and handover calls'load are specified. Propose a new algorithm of the new call and handover call blocking probability in a specifically integrated service systems model based on the channel reservation strategies, this study also considers the problem of the typical handover strategies. The model is simulated, and the result coincides well.