Application Of Time-Domain Numericalalgorithm For The Wireless Channel Analysis

Wireless communication is a popular orientation of communication research; as the transmission medium, the radio channel has significant influences on it. Therefore, it is necessary to do a research on the radio channel. Traditional measuring method costs too much, and the channel characteristics of specific environment can not obtained from statistic modeling; however, deterministic modeling is a very important method, which can remedy the defects of the two modeling methods above. Two time-domain numerical algorithm are applied to establish the deterministic model of radio channel, including finite-difference time-domain method (FDTD) and time-domain finite-element method (TDFEM). On the basis of deterministic modeling, the CLEAN algorithm is used to analyze the time-domain characteristics of radio channel.For details, see as below:(1) Based on domestic and foreign literatures, the research methods of radio channel are reviewed, and the deterministic modeling methods are introduced, consisting of FDTD and TDFEM.(2) In the thesis, the FDTD is applied to model the radio channel, and the waveforms of receiving points are calculated; meanwhile, in comparison with the result of software simulations, our radio channel simulation program, which is based on FDTD, is proved to be correct. However, there are some shortcomings on analyzing the complex geometry by FDTD based on Yee grid, such as the difficult modeling on the complex geometric boundaries. In this case, dense partition is indispensable, but this leads to much more complex calculations. For this issue, we use the TDFEM method, which can fit to the geometric boundaries better, and apply the method to radio channel. Taking the tent and tunnel mode for example, we use this method to obtain the waveforms of receiving points, and compare the results obtained by FDTD method. At last, the accurateness and effectiveness of TDFEM on analysis of radio channel are verified.(3) On the basis of time-domain data processing program of CLEAN algorithm, impulse response of actual radio channel is extracted. Furthermore, the improved deterministic multi-template method is used, in order to extract the channel impulse response of the tent model. The parameters related to radio channel are obtained, such as the mean excess delay, RMS delay spread, multi-path number under 10dB peak and the factor of path loss. Eventually, the accurateness is verified by comparing to existing software results.