Research On Some Key Technologies Of LTE System

Long Term Evolution (LTE) was introduced in 2004 and has been evolving afterwards. It's one of the topics with most concern from both academic and industrial field of telecommunications. The USA aims to deploy commercial use in 2011 and most advanced communication companies such as CMCC, Huawei, ZTE are working on it. LTE aims at enhancing the data rate while lowering the systematic latancy, working with higher capacity and dealing with the coverage issue of the cell edges. Also, the LTE has high compatability with 3G and 2G wireless telecommunication networkes.In LTE telecommunication systems, with the use of lots of novel technologies such as higher carrier frequency, more flexible bandwidth, it can provide hundreds of Mbps bandwidth. Also, the all IP-based architecture can provide higher compatability with 2G and 3G telecommunication systems.During the meantime, high compability means that all kinds of wireless communication systems such as GSM, WCDMA, CDMA2000, HSPA will co-exist in the same network. That means Radio resource management issue may become more and more important. The thesis mainly focuses on raido resrouce management and the GA based radio resource management issue in LTE. The thesis mainly consists of the following aspects:(1) LTE telecommunication systems is divided into several sub models. Systematic simulation setup is based on the sub models. The systematic simulation model provides reference for future research on LTE.(2) Theoretically analyzed the content and method of radio resourse management issue in LTE, especially the antenna pattern adjustment and power control issues. The user coverage issue in LTE is theoretically analyzed. Because of the co-existence of different wireless telecommunication systems and the support of high data rate applications, the throughtput issue and coverage issue are more complex. Theoretical reaseach on SINR, cell coverage and cell throughput are done based on the systematic model. The relevance of the transmission power of the base station and the cell throughput and cell coverage are investigated and verified by simulation.(3) GA module is set up based on the systematic simulatior of LTE system. By GA, by the reasonable design of single-objective and multi-objective fitness functions, combined by the use of semi-smart antennas, through which the transmission power is adjusted, the coverage and throught issues of the multi-cell model are optimized based on different user distribution scenarios.(4) Research on the frequency reuse of LTE telecommunication systems. The frequency reuse issue is of great importance based on its flexible bandwidth, supporting of various applications and good compatibility of the other wireless telecommunication systems. A novel frequency reuse scheme is proposed to enhance the system throughput. The scheme is testified by simulation based on the systematic simulator.(5) The optimized radio resource management results in LTE system are investigated. Because of the existence of random crossover, selection and mutation procedure of GA, the evolution route of GA may vary a lot. The robustness issue is theoretical analyzed and testified through simulation. The interference of crossover rate of the GA based LTE system is investigated. The value of crossover rate may interfere the constitution of the offsprings of GA, thus may change the evolution route and performance of GA. The interference of cross over rate on the GA is theoretically analyzed and testified throuth simulation and reasonable crossover set up is investigated in GA based LTE system to get the optimized radio resource management results effectively.