Research On MIMO Spatial Multiplexing Techniques In TD-LTE System

The Multiple Input Multiple Output (MIMO) is a communication system with plurality ofantennas at the transmitting end and receiving end. Generally, multi-antenna systems such asMultiple Input Single Output (MISO), Single Input Multiple Output (SIMO) can also be viewed asa special case of MIMO. MIMO can effectively improve the channel capacity, improve systemperformance, so it is considered to be an important way for future mobile communications toachieve high-speed data transmission, and improve the transmission quality.Long Term Evolution (LTE) as the fourth-generation mobile communication technology, canachieve high data transfer rate. Most important technologies such as OFDM and MIMO areconsidered as the most important reason why LTE can achieve such a high peak data rate. Mainlythere are two application modes of the MIMO in the LTE System, one method for improving thelink quality, which is the MIMO transmitting diversity; another method for improving data transferrate, which is the MIMO space division multiplexing.In this thesis, we study the three application modes of the multi-antenna technology, includingreceiving diversity, transmitting diversity, and space division multiplexing in the common wirelesscommunication system otherwise the LTE system. Then, we study a variety of key technologiesrespectively in physical layer of TD-LTE system associated with the application of MIMO inTD-LTE system respectively. In order to study the principles of OFDM technology, this thesisestablished a simple OFDM simulation model to simulate the process of sending and receiving forOFDM systems, and analysed its anti-noise performance. Especially, we analysis and make acomparison among various application modes of MIMO technology in TD-LTE system in detail.In the next move, we derived the channel capacity formula for MIMO system using themathematical methods, and make a simulation and analysis on MIMO channel capacity and systemperformance. And the relationship with the channel capacity and the number of transmittingantennas and receiving antennas is given in the three-dimensional coordinate. The thesis alsodiscussed the different effect of waterflood algorithm and average power allocation algorithm onMIMO channel capacity.TD-LTE protocol supports both the pre-coding techniques of the codebook-based andnon-codebook. The thesis mainly discusses the several channel decomposition based pre-codingalgorithm, including the singular value decomposition algorithm, geometric mean decomposition algorithm, uniform channel decomposition algorithms and LDL~H algorithm, all of which belong tothe category of non-codebook precoding technique.