Research On Radio Resource Management Of Femtocell In LTE-A System

With the development of Mobile Internet and some novel services, mobile users have new demands, such as the diversification of wireless services and high-speed of data. All demands promote the development of communication technology and3GPP has launch LTE/LTE-A evolution project to enhance the network coverage, to increase the energy efficiency and to improve the customer service quality further. Several researches have shown that in the next generation of wireless communication network, the indoor scenario will become the hot issue. Hence, the study of femtocell will become the focus of academic research, as well as the profit point of operators and equipment manufacturers.First of all, this thesis focuses on the basis of femtocell involved two-tier network in LTE-A system and analyzes the network architecture, access method and wireless radio resource management. Second, decrease of energy consumption and enhancement of network coverage are two main goals in LTE-A network. Therefore, this thesis studies from the perspective of joint radio resource management and coordinated multipoint transmission/process technology respectively.In the aspect of energy cost, the thesis proposes a joint radio resource management based on energy efficiency and realizes the trade-off between data rate and power consumption. This thesis designs a utility function based on energy efficiency. Furthermore, to guarantee the fairness in two-tier network, a pricing mechanism is introduced to protect links of femtocells. In the proposed algorithm, the joint wireless resource management could be converted into two-step iterative optimization problems. In the first step, based on the results of the scheduled sub-channel results, the supermodular game theory is utilized to guide power control. In the second step, the assigned power results are taken as conditions for sub-channel scheduling. Finally, the best resource allocation response is implemented through the iterative process, The simulation results show that joint radio resource management could guarantee user fairness in two-tier network and enhance system energy efficiency.In the aspect of network coverage, there exists serious intra-tier interferences cross-tier interferences in. femtocell involved two-tier network. The coordinated multipoint transmission technology could convert interferences to useful signals, increase the data rate of,cell edge users and enhance network coverage effectively. The semi-dynamic clustering strategy can guarantee the clustering performance, and reduce the clustering complexity and data exchanging cost. Further, a CSI based iterative scheduling algorithm and a coordinated degree based suboptimum scheduling algorithm are presented. The algorithms could make full use of limited channel information to realize the optimization of the scheduling process, the increase of data rate for users, especially edge users and the enhancement of network coverage.