Hsdpa Wireless Communication System In The Cell Selection And Admission Control

HSDPA is introduced as one of the evolution of WCDMA to meet the rapidly developing needs of data service. HSDPA provides a new channel called HS-DSCH, through which downlink rate can reach 10.8Mb/s. The definition of physical layer of HSDPA in the first stage is almost completed, but Radio Resource Management is under development.FCS has been proposed for HSDPA. With FCS, only one cell is selected by UE to provide UE with HS-DSCH service at any time, but UE can update the cell selection once every 3.33ms and change serving cell rapidly. In the performance analysis of 3GPP, only the tradition serving cell selection is considered, which is only based on SIR. However, 3GPP recommends that determination of the best cell not only be based on radio propagation conditions but also available resources. In FCS, UE selects one and only one cell from its active set. Though the handoff of HS-DSCH is hard handoff, the update of active set is the same as soft handoff. The admission control for real time service is not defined in 3GPP and there are few literatures on it.In Charter 2, a system model is set up according to the definition and allocation of resources in HSDPA. In the model, average load factor and service time is defined. In Charter 3, Short Service Time Cell Selection is proposed based on the summarization of the methods of serving cell selection in existence and the definition of service time in Charter 2.In the simulation built up by OPNET, the results show that Short Service Time Cell Selection is better than the traditional method only based on SIR and LA-CSS/LA-HO proposed by A. Sang on the whole, making good use of spare resources and reducing the packet delay. Another result shows that with condition B, ongoing call blocking probability is reduced at the cost of higher new call blocking probability, but the total blocking probability is reduced while the QoS doesn't degrade. The research of HSDPA is valuable as HSDPA is a typical wireless packet access system.However, the Radio Resource Management is under development. Service cell selection and admission control is one of the most important RRM techniques. Short Service Time Cell Selection and Admission Control Condition B proposed in this thesis is one of the suggestions of RRM solution.