Modelling And Measurement Of The MIMO Radio Channel Based On 3GPP LTE

3GPP is the most influential establisher of technical reports and technical specifications of 3G and B3G In recent years, kinds of systems like WCDMA, TD-SCDMA, and HSPA have been widely deploying all over the world, in addition, 3GPP initiated some new projects of long time evolutions including LTE, HSPA+, and LTE-Advanced.LTE system adopts MIMO and OFDM as its two most important fundamental techniques, so as to respond to the requirements of large capacity and high spectral efficiency. MIMO system adopts multi-antenna systems on both sides of sender and receiver, sending and receiving signals at the same time, fully making use of space resources, improving system performance without extra transmitting power and spectrum resource. MIMO more and more play an important role in the current development of wireless communications. Some relevant techniques of MIMO like signal processing, encoding/decoding, modulation/demodulation, and resource management are at the forefront of research and design of mobile communications. However, there are still many remaining problems of MIMO system are urgently wanted to be studied and solved. This dissertation mainly discusses the MIMO theories which are based on the framework of 3GPP LTE system, some new strategies are presented as follows:1. This part is mainly concerned with the systematic analysis of the signal correlations in MIMO channels, this analysis of signal correlations for the MIMO systems establishes solid theoretical basis for MIMO channel modeling, channel capacity, and so on. Firstly, providing four-antennas on receiver, mutual coupling, four kinds of classical PAS, and antenna spacing which characterise the MIMO systems, mathematically deducing and analyzing the expressions of signal correlations on receivers, so that explaining the relationships of correlations and parameters of MIMO systems; Secondly, explaining the differences between signal correlation and channel correlation based on the above-mentioned expressions and the Kronecker model, then analyzing the channel correlation by Kronecker theories; Thirdly, combining with some key techniques of MIMO, analyzing the root causes of the important role which the correlation plays in the performance of MIMO systems. 2. This part is mainly concerned with the MIMO wireless channel modelling. Firstly, discussing fundamental differences between traditional SISO channel modelling and MIMO channel modelling, the key methods of MIMO channel modelling theory; Secondly, analyzing some current classical MIMO channel models with basic modeling methods, and offers the validation procedures of simulation of MIMO channel models; Thirdly, based on the above-mentioned discussion, separately making use of ray-tracing and correlation matrix to model the MIMO channel based on the 3GPP 25.996 technical report, that is, expressions of channel transfer function of spatial diversity, polarization diversity, hybrid diversity and LOS situation are derived respectively by ray-tracing, based on the results, the expressions of spatial correlation matrix, polarization correlation matrix and time correlation matrix are derived; Finally, deducing and mathematically analyzing the impacts on the channel capacity from channel spatial correlation and time correlation, then offering the validation procedure of simulation of MIMO channel models which established by two the above methods respectively.3. This part is mainly concerned with the measurements and estimations of MIMO channel. The emphasis are: PDP, PDP shifts, DPSD, Doppler spread, BF, multi-path number, coherence bandwidth, coherence time, correlation of multi-path fading, power fading of the receiving signals, and correlation of CIRs of given antenna architectures, etc. Firstly, principles can be divided into three parts: l).How to get CIRs, PDP, by which other parameters can be obtained. 2). Proposing a simple and effect plan for estimating the Maximum Doppler spread, discussing the practical factors which influence the accuracy of the estimation of Doppler spread, validating the conclusions by simulation. 3). Proposing an improved plan and assessment ways for the BF algorithm under a limited CSI feedback MIMO system; Secondly, configuring communication scenarios based on above-mentioned principles and 3GPP LTE specifications, obtaining and analyzing the CIRs, PDP, and other channel parameters, so as to draw some conclusions about MIMO channel and propagation. Finally, introducing the whole framework of LTE prototyple's software system, and exemplifying its implementation on a simulation platform named Linkstar.