| At the cell edge area, the handoff and user’s communication experience are two mostimportant issues for cellular wireless communication systems. With the rapid developmentof Chinese high-speed railways, and the rise of variety of mobile terminal equipment andbusiness, how to provide an anytime, anywhere high-quality mobile communicationsservices is particularly important. An accurate handoff model is required to model andanalyze the handoff process in cellular networks. This result can provide a theoreticalbasis for the design of high-performance handoff algorithm. On the other hand, the impactof interference in the area of the cell edge severely limits the performance of the user atthis area. It is necessary to design a complete simulation platform to verify the variousoptimization algorithms in MIMO environment which is used to improve the cell edge andoverall performance.First, this thesis studys the handover process of a two-cell system. Using the statetransition modeling idea and the conventional hard switching algorithm, we derive ananalytical expression of handover success rate and the average handoff times when theuser moves along a certain trajectory in the overlapping area in the cell with a constantspeed. Furtheromore, some simulation is carried out and performance is analyzed. Base onabove results, an adaptive handoff algorithm which can be applied to high-speed railenvironment is developed. The handoff threshold is optimized to improve handoffperformance by our proposed algorithm. Simulation under the influence of the differentspeed is valided at last.Finally, based on a multi-cell cooperative user scheduling algorithm, a cooperativemulti-cell computer simulation platform is developed, which contains a hardware part anda software part. Through the platform, we verify the algorithm mentioned above whichcan improve the edge users’ performance, but also provides a platform that can be rapidlyextended to the next step advanced algorithm design. |
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