Research And Simulation Of Handoff Algorithm In ROF Cell System

In the last decades, the shortage of radio resource became increasingly serious while wireless communication techniques are widely used. Strategies that aim to improve spectrum efficiency are always hot research topics. This thesis focuses on the technologies of handoff schemes in one of the solutions for future mobile communication, Distributed ROF System. Some new algorithms have been proposed to improve handoff performance.Based on deep research in the handoff technology of the traditional mobile communication system, this thesis first analyzed the changes of handoff schemes. According to the architecture of ROF system, the antenna adding and removing technology is used to achieve handoff instead of the choosing base station.Some handoff algorithms in distributed ROF system are proposed based on the researches of the handoff technology in Distributed Wireless Communication System. These algorithms include single cell handoff algorithm under single-mode service and single cell handoff algorithm under multi-mode service, ROF cell group handoff algorithm and dynamic cell group handoff algorithm. Furthermore, this thesis compared these handoff algorithms by experiment. The simulation results shows that, comparing to single-mode service, the algorithms under multi-mode service can effectively reduce the number of handoffs, and increase the average signal strength. Under multi-mode service, ROF cell group handoff algorithm can provide better handoff performance than single cell algorithm; dynamic cell croup algorithm can effectively improve the antenna utilization rate.Finally, base on the research of single-user situations, a mathematical model which is used to analyze the system blocking rate of multi-user situations is designed. The simulation shows that dynamic cell group handoff algorithm can reduce the system blocking rate.