Research On Key Technology Of Femto-Cell

Along with the booming of mobile internet, users'desire of high-speed mobile data services is ever-growing. The technical specifications of 3G and LTE networks stress on improving transmit rate in mobile data services. Indoor coverage of wireless communication system has been an unsettling issue for a long time; however, in the context of pursuing high-speed data transmission, it becomes an urgent task to upgrade indoor signal quality. Because of its excellent system-capacity-extending capability, high quality voice and data services and better user experiences, Femto-Cell is a very competitive candidate for indoor coverage.This paper investigates Femto-Cell technology in environment noise and interference management along with access and handover control.In research of environment noise and interference management, cognitive radio is introduced into femto-cell, resulting in the concept of femto-cell with cognitive capability. The cognitive capability to understand radio environment in cognitive radio can be used to deal with inter-cell interferences when widely deploying Femto-Cells. Game theory is employed to model interaction behavior between FBSs, and an uncooperative game with carefully designed utility function is proposed. Existence and uniqueness of Nash equilibrium of this game are proved; a distributed power control algorithm based on this uncooperative game model is put forward. Then cooperative game theory is used to optimize the uncooperative solution. By associating power control with spectrum sharing, a distributed resource allocation algorithm on basis of cooperative game model is designed. These two algorithms are simulated under different scenarios. The simulation results proves the correctness and effectiveness of the uncooperative-gaming-based distributed power control algorithm, and also shows that the cooperative-gaming-based distributed resource allocation algorithm can solve the problem in uncooperative game and assures system stability.In research of access and handover control, we firstly present problems and technical difficulties of handover control in wireless communication system with femto-cell. A schema based on femto-cell network architecture is given out to help design handover control method, which is aiming to solve handovers between adjacent femto-cells and from femto-cells to macro-cell. Then we choose widely-deployed W-CDMA technical specification as object of study on physical layer access technology in femto-cell. According to access procedure of Femto-Cell, we study cell search procedure and baseband pre-processing in W-CDMA system; and we implement a W-CDMA subsystem on hardware platform. In pre-processing module of baseband receiver, algorithms are proposed to deal with frequency offset of received signal and sampling frequency offset in receiver. In cell search module and RAKE receiver module, improvements and optimization are made on the basis of existed algorithms to reduce computational complexity, which is good for implementation on hardware.A multi-mode Femto-Cell experiment platform is given out at the end of this paper. With a unified hardware system framework, different wireless communication systems are implemented in software. This kind of design improves flexiblility and scalability of the platform. We implement part of a W-CDMA system on the proposed platform, showing that it is feasible for development of wireless communication system on basis of this experiment platform, which is of some certain of practical value.