Research And Evaluation On Enhanced MIMO And Carrier Aggregation Technology For LTE-Advanced System

The next generation of wireless communication requires higher transmission rate and lower transmission power, but it is challenged by limited spectrum resources, discrete carrier frequencies and poor environment. In order to solve these problems, multiple-input multiple-output (MIMO) technology and carrier aggregation (CA) technology are proposed. Particularly, MIMO technology has the ability of supporting high-speed data transmission, improving spectral utility and increasing power efficiency, while CA can aggregate multiple discrete carriers to increase spectral utility and system bandwidth. Recently, MIMO and CA have become the hot issue in wireless communication research, and the core technology of LTE-Advanced system. With the support of research project, this thesis has performed the research and simulation of enhanced MIMO and CA following LTE-Advanced standardization. Achievements are stated as follows:1. Research on enhanced MIMO. To reduce co-channel interference of virtual MIMO and achieve optimal system throughput under Coordinated Multi-Point transmission and reception (CoMP) scenario, this thesis proposes a new user pairing scheme. The scheme is mainly based on particle swarm optimization algorithm and is designed for all CoMP-MU-MIMO scenarios. The performance and complexity of this scheme are analyzed by simulations. Furthermore, to improve the channel feedback accuracy and performance of SU-MIMO and MU-MIMO under enhanced MIMO scenario, this thesis proposes a closed-loop feedback scheme of user channel information based on codebooks. This scheme can feed back multiple PMIs to achieve optimal feedback both for SU-MIMO and MU-MIMO, and simulation results show that it can obtain the better performance than the original LTE feedback scheme.2. Research on CA technology. This thesis analyzes the effect of CA technology on hardware structure and RF link in LTE-A, and establishes a co-simulation platform of baseband and RF for LTE/LTE-A systems with MATLAB software and ADS software. This co-simulation utilizes strong data processing ability of MATLAB software and advanced RF simulation ability of ADS software skillfully. And the platform can support the 3GPP RAN4 BS conformance testing of occupied bandwidth, adjacent channel leakage power ratio, error vector magnitude and so on. What’s more, this thesis develops a method of testing the occupied bandwidth for large bandwidth system, which can satisfy the requirement of sweep span and resolution bandwidth in a certain period of time.