Research On Indoor MIMO Wideband Radio Channels

The Multiple-Input Multiple-Output (MIMO) is one of the key techniques for the fourth and fifth generation of wireless communication systems. It can be used to increase the communication capacity without increasing the transmission power and play an important role in relieving the pressure caused by the lacking of frequency spectrum resources. On the other hand, with the development of Internet of Things and promotion of intelligent terminals, wireless transmission in the indoor environment increased significantly, and the high quality of wireless communication were required. Therefore,, the research of MIMO radio channel is important for future communication system. MIMO channel modeling is the most important way to study MIMO technique which can provide the reference in link and system level simulations, network optimization and design for new radio systems.The summary of MIMO channel models has been studied in this thesis first, and then and the Tapped Delay Line (TDL) models for indoor environment in the Line-Of-Sight (LOS) and Non-Line-Of-Sight (NLOS) scenarios have been proposed and the characteristic of indoor MIMO channel has been analyzed. The main research contents and innovative work in this paper are as follows:Firstly, the MIMO radio channel modeling approaches are summarized, including the advantages and disadvantages of each approach and their deployment cases are presented. An improved sliding correlation method is applied to achieve the MIMO channel impulse responses (IRs). By using the measurement data with noise cut in different indoor scenarios, radio channel parameters are analyzed and comparisons are made between the simulation and measurement results.Secondly, the radio propagation characteristics of indoor scenarios have been studied. The power attenuation law is analyzed in both of the LOS and NLOS indoor scenarios and the TDL model are proposed. Validation of the TDL models is made by various ways. The advantages and disadvantages of the TDL models are presented by discussing the tap correlation and frequency correlation functions.Thirdly, the indoor MIMO radio channel characteristics are studied by analyzing radio channel parameters in both of the LOS and NLOS indoor scenarios, e.g. power delay profile, delay characteristics, tap amplitude distribution, number of multipath, tap Doppler spectrum, K-factor and channel capacity. Studies shows that the distribution of power delay profile, tap amplitude distribution, taps correlation, tap Doppler spectrum are significantly different between the LOS and NLOS scenarios, and the distributions of root mean square (RMS) delay spread, K-factor and the number of multipath follow the same distributions in the LOS and NLOS scenarios, respectively. MIMO channel capacity in the LOS and NLOS indoor scenarios has no big difference but both are smaller than the ideal i.i.d channel.The research on the indoor MIMO channel models and characteristics in this thesis can provides good reference in the link and system level simulations, network design for new indoor wireless systems.