The Research On The Leaky Bucket Algorithm To Improve The Quality Of Service In GPRS System

General Packet Radio Service (GPRS) is a digital technology, which is called 2.5G. Originally there was some thought to extend GPRS to cover other standards, but instead those networks are being converted to use the GSM standard, so that is the only kind of network where GPRS is in use. It provides moderate speed data transfer, by using unused TDMA channels GSM network. GPRS adds packet switching mode to GSM network. Based on GSM network and technology, GPRS make full ues of the wireless structure of CSMsystem and it greatly accelerates the convergence of wireless communication and data networking by inrroducing packet swritching mode to GSM network. GPRS system includes real-time service(including audio and video) and unreal-time service(including data). Because of the difference of QoS, the GPRS may congest. To meet the demand of QoS in GPRS system, the flow and congestion of GPRS networks become very important. This thesis discusses the flow control of integrated-service in GPRS.This paper mainly consists of two parts. In the first part, firstly I give a review of the GPRS mobile communication system and the request and structure of QoS in GPRS. Then I introduce in detail some relevant technology in GPRS networks including networks units,interface,terrace and protocol etc, Arming at the problem of the integrated-service in GPRS, I discuss its natrue and classification in detail. In the second part, the focus is on the network policing algorithm in GPRS and I have proposed two algorithms for integrated-traffic in GPRS networks, one is the single velocity leaky bucket algorithm and the other is the dual velocity leaky bucket algorithm. Three simulated model have been used, Poisson model for data service, ON-OFF model for audio and Markov model for video. By analyzing these two algorithms with queue theory , we obtain the analytical expression of the relation among the leaky bucket performance . the leaky bucket parameter and the statistical parameter of input traffic. Simulation with matlab indicates that QoS can be guaranteed by these two algorithms and the data service can get a high channel utilization ratio on the condition that the total service flow cannot exceed the value stipulated by the protocol. These two algorithms will meet the demand of QoS in GPRS better.