| In the framework of IMT-Advanced (International Mobile Telecommunication-Advanced, abb. IMT-A) standardization,3GPP (The 3rd Generation Partnership Project) launched LTE-Advanced (abb. LTE-A) standardization after LTE (Long Term Evolution) in order to totally meet the systematic requirements of IMT-A. LTE made a technical revolution compared to 3G (The 3rd Generation Mobile communication), by adopting advanced wireless transmission technologies, such as MIMO (Multiple-Input Multiple-Output) and OFDM (Orthogonal Frequency Division Multiplexing) and a new form of flattened network architecture, leading to a substantial increase in data rates and system capacity; As a further enhancement technology of LTE, LTE-A is a smooth evolution based on LTE and will be the candidate of 4G (The 4th Generation Mobile Communication) standards submitted to ITU by 3GPP. LTE and LTE-A is a succession of evolution plan of 3GPP aimed to 4G.The topic of this dissertation comes from "IMT-Advanced Technology Program Research and Key Technology Evaluation", the 11th five-year key project of Ministry of Industry and Information Technology. The topic is mainly to design and implement a link level simulation platform for LTE/LTE-A downlink based on specifications and requirements of 3GPP R8 and R9 on physical layer and data link layer, and then evaluate performance of key technologies, to support IMT-A technology proposal and the following standardization.In this dissertation, we first outline the standardization process and technical overview of LTE/LTE-A, and give a brief introduction of theory, methods and tools of the link level simulation. Then, we discuss the total design and modular design and implementation of LTE/LTE-A downlink link level simulation platform, simulate and analyze the performance of related technology of some modules, such as channel encoding and decoding, modulation and demodulation, MIMO-OFDM and AMC/HARQ (Adaptive Modulation and Coding/Hybrid Automatic Repeat Request) mechanism.Finally, we research some key technologies of LTE/LTE-A downlink, including space-time coding, MIMO channel modeling and channel estimation. In detail, we discusse non-codebook and codebook based space-time pre-coding technology, simulate and analyze pre-coding performance and feedback overhead; we realize IMT-Advanced channel modeling, simulate and analyze the channel characteristics of different test scenarios; at last, we study Wiener filter based channel estimation algorithm, showing the reasons of its excellent estimation performance. |
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