Study And Simulation Of Mobile Communication Channel Models

Mobile communication as one of the main roles in the future personal communication is widely applied. In mobile communication, for the movement of the mobile terminal, the received signals are affected by the multi-path fading and shadow effect. Thereby the communication channel between the base station and the mobile terminal constrains the performance of the whole system. Researching the propagation and variability of the electromagnetic wave and constructing the channel model can simplify the calculation of fading parameters, supply the reliable reference for system design, and select the optimal modulation, error coding and multiple accesses.A new statistical model for non-frequency mobile radio channel is presented in this paper. The study contains three aspects as follows: 1. The paper introduces Suzuki process as the basic model in wireless channels. In the model, the shadow affects the component of the multi-path. The shadow affect is logarithmic normal distribution, and the multi-path fading is Rayleigh distribution. The model conforms to the real transmission environments of electromagnetic wave better. The paper gives the probability density function of the envelope of received signal and the approximate expressions of Level-Crossing Rate and Average Duration Fades.2. The paper establishes the deterministic simulation model using the theory of sine summation. The model parameters are determined using the Method of Equal Distances and the Method of Equal Areas. The paper explains the reasonableness of the model through comparison of autocorrelation function. At the same time, a wideband model is put forward. 3. The paper studies the digital transmission technology i.e. modulation and demodulation technology in the typical channel. Based on the analysis of error bit performance of different modulation technology in this channel, the paper derives the error bit rate formula of the channel model assuming the compound effect of the multi-path fading and the shadow. At last, the paper analyzes the error bit rate of QPSK modulation in DS/CDMA system. The advantages of spreading frequency QPSK modulation are discussed. The conclusion is important to the mobile communication system for designing, analyzing and evaluating performance.