Quality Of Service In General Packet Radio Service

With the recent development of wireless technology and Internet,there arise increasing demands for radio packet service. And GPRS (General Radio Packet Service) as the 2.5 era mobile communication system has attract more attention form people. Based on the GSM, GPRS uses the idle channel to transfor the radio block. And as the transition to the third mobile communication system, GPRS is used widly.In the system of GPRS, There is not only the high level transferring protocol of packeted data, but also try to offer Quality of Service. Although GPRS defines several service levels, it does not describe the process of QoS control in detail. In this paper, firstly we will introduce the potocol and basic structure of GRPS. Then we will discuss several QoS mechanism which is already existed, including Access Control, Resource Obligate, Shape and Queue Management. We will describe them in detail in order of the level. After that we will present a new QoS solution in the whole GPRS network. The new solution is composed by the diff-serv model and inter-serv model. The traffics with the highest priority will be transfored by inter-serv model, and the network will reserve the channel to fullfill the demand of traffics. On the other side, the new solution use the diff-serv model to transfor the traffics with the lower priority. The nodes will service the traffics according to theirs priority. In this paper, we will use the Minimum Laxity Threshold Algorithm (MLT) on the PCU and Token Bucket Algorithm on the GGSN.