The Research And Simulation Of Radio Admission Control In WCDMA System

The WCDMA technology is one of the main standards of the third Generation mobile communication system (3G) while Radio Resource Management (RRM) is an important way for its implementation. This thesis briefly introduces the key technology of system RRM and further research is done with the Radio Admission Control (RAC) policy and also its application in Hierarchical Cell System.WCDMA is an interference-limited system. A setting up of new call connection will result in the load enhancement of both uplink and downlink and affect quality of service of the present activated calls in the system. The access of new call may lead to the breaking off to the present call connection and the instability of system when the system is loaded heavily. In order to ensure acquiring the maximum system capacity while the system is at the stable state, we must adopt Radio Admission Control policy that judges whether to access a new call according to the present load and requirement stability of system. Radio Admission Control is the key technology to ensure the quality of multi-class service and improve system capacity.This thesis analyse the Radio Admission Control algorithm that based on interference—threshold. It does further research about the realization process of the algorithm in admission control process of new call service and the test results validate its feasibility and validity through WCDMA system test. And referenced data are provided for the design of the real WCDMA system.And then, the thesis analyses separately the Uplink interference of macro-cell and micro-cell combining the characteristic of hierarchical cell system of WCDMAThe algorithm that based on interference—threshold is applied to the hierarchical cell system. System timely deals with the call requests according to the interference level of local cell and adjacent cells, which ensure the communication quality of present activated calls and the stability of system.Two typical services including voice and data are simulated using OPNET network simulation software and get the result that the block radio of voice service and ftp data service in new calls and handover calls. The simulation resultvalidates the feasibility and validity of this algorithm. And referenced models and algorithm are provided for the programming and design of the hierarchical cell system of WCDMA.