Research And Simulation Of The Capacity And Coverage In HSPA+Networks

HSPA+is an important wireless network standard. The research on its capacity and coverage has great significance to the actual cellular network deployment and optimizaion. At present, most of these researches are realized through system-level simulation.In these simulations, a uniform user distribution is often assumed within a cell. However in a realistic cellular network, users are often not uniformly distributed as assumed by many previous studies. There are hot spots where there are more users trying to get access to the wireless network such as shopping malls, train stations, office buildings, downtown area and etc. This clustered feature of user distribution will lead to a different system performance from the uniform distributed one.Besides, since thelocation of a base station is depended on many factors such as available infrastructures, costs, feasibilities and etc. Hot spots may not always coincide with base station centers.The evaluation of users’ distribution on HSPA+network capacity needs to be handled with great care. In addition to user distributionpatterns, with the envolution of cellular systems, as well as enchanced processing capabilities of mobile terminals, users’ traffic diversifies, particularly in forms of the softwareapplicationsatthe mobile terminals side. It is also of great importance to evaluate the influence of different traffic models on network capacity.In this paper, in-depth study of different user distributioin models and traffic models are carried out. Combined with HSPA+network, the impact of each model on system capacity is also studied. The main work of this paper is as follows: ①Build a HSPA+system-level simulation platform that implements the user module, base station module, propagation module, scheduling module and data analysis module.②Proposed a two-dimensional truncated Gaussian user distribution model, compared its impact on system capacity under maximum carrier to influence scheduling and round robin scheduling. Simulation results show that with the decrease of user’s concentraton level, system capacity decreases significantly, and the decrease under round robin scheduling is faster than that under maximum carrier to influence scheduling. Meanwhile, the shift of users’distribution center also has great impact on system capacity. The more centralized the users, the faster the decline of system capacity with the shift of users’distribution center.③Studied two types of data traffic models:Full buffer traffic model and burst buffer traffic model. Analyzed and compared the capacity of HSDPA network under the two traffic models. Simulation results show that when users are uniformly distributed, the total system capacity under bursty raffic is largely influenced by traffic arrival rate. System capacity under full buffer is always better than that of burst buffer when users are non-uniformly distributed. Unlike full buffer traffic, under busrt buffer traffic, maximum carrier to influence schedulingis more affected by users’ uneven distributionthan round-robin scheduling.