Research On Radio Resource Management Techniques In Ofdma-Based Femtocell Networks

With the rapid development of mobile communication technology and the popularization of various intelligent terminals, more and more mobile service happened in indoor, so it is more importment to provide better indoor coverage for users. The orthogonal frequency division multiple access (OFDMA)-based femtocell network can enhance the indoor coverage very well and improve indoor capacity. It has a very broad market prospect. Radio resource management is the key technology for femtocell network, which can effectively reduce the interference and improve the quality of service for users.In this paper, the technology of radio resource management for femtocell network in LTE-A network has been researched deeply. The advantages and disadvantages of previous indoor coverage solutions have been summarized and analyzed. The concept and key technologies of femtocell have also been introduced in this paper. In order to reduce the interference by allocating radio resource in femtocell network, two radio resource allocation algorithms are proposed:User Classifying-based Hybrid Spectrum Allocation (HSA) Algorithm and Downlink Power Control with Firefly Algorithm (PC-FA). Then the two algorithms are verified by system level simulation.A novel classification mechanism of users is proposed in HSA.The macro users are classified into several categories based on their geographic location, and femto users are classified according to the categories of macro users. Then, based on such user classifications,a new dynamic hybrid spectrum allocation algorithm is proposed in HSA.The simulation results show that the HSA can improve the outage and throughput performance of macro users,and achieve a good tradeoff between the performance of macro and femto users, comparing with previous methods.PC-FA has introduced swarm intelligence optimization theory and modeled the objective of power control with utility functions for macrocell and femtocell with considering the factor of area spectral efficiency. Firefly algorithm is employed in PC-FA to effectively solve the power allocation problem in Femtocell network. The simulation results show that PC-FA can improve the throughput performance of femto users and the total throughput performance of femtocell network with minor impact on macro users. Meanwhile, PC-FA also considers the performance of macro and femto users and achieves a good balance between them.