| Summary: | 碩士 === 國立臺灣科技大學 === 電子工程系 === 88 === The General Packet Radio Service (GPRS) is a new bearer service for GSM (Global System for Mobile Communications) that can greatly improve and simplify wireless access to the Internet. In the GPRS, the packet radio principle is applied to transfer user data packets in an efficient way between mobile stations (MSs) and packet data networks. The radio resources of a cell are shared by both the GPRS and GSM voice service. The allocation of physical channels to either packet-switched (GPRS) or circuit-switched (conventional GSM) services can be performed dynamically, depending on the traffic load and the service priority.
In this thesis, we will study the design of radio resources allocation between conventional GSM services and GPRS. The call admission controller and bandwidth allocation controller are employed to obtain good bandwidth utilization without affecting the QoS of conventional GSM services and GPRS. Static guard channels are used to prioritize GSM voice handoff calls. The static guard channel scheme has the drawback of low bandwidth utilization. Temporary allocation of these guard channels to GPRS users is discussed to solve this problem.
Compared with the channel allocation model without call admission controller and bandwidth allocation controller, our simulation results show that in low voice traffic load case, the proposed scheme can achieve lower voice call blocking probability, new and handoff, and better channel utilization whereas does not increase GPRS connection rejection rate when the GPRS connection requests is low. When voice traffic load is high, the new call blocking probability can still be kept below the target value.
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