Mobile-to-mobile channels: Statistical and empirical models
In this dissertation, we first present statistical models for cascaded Rayleigh Isotropic fading channels with and without line-of-sight (LOS). These models contain two individual summations and are, therefore, easy to implement with lower complexity. Detailed statistical properties, including auto- and cross-correlations of the in-phase, quadrature components of the channels, envelopes, and squared envelopes are derived. The time-average statistical properties and the corresponding variance are also investigated to justify that the proposed models achieve good convergence performance. Then, we present mobile-to-mobile (M2M) channel measurements at 2.1GHz and 700MHz bands in suburban and forest environments. Four test scenarios are considered for the transmitter (Tx) and receiver (Rx) placed inside traveling vehicles or on a test cart pushed at a walking speed. Channel models are proposed for path loss, shadowing, small-scale fading based on measurements. The path loss exponents were found between 1.2 to 7.7, and the reference path loss is found larger due to the placement of antenna inside vehicle. The mean of shadowing is close to 0, and the variance varies from 1.8 to 4.9. Measurements suggest that small-scale fading follows distributions of the Weibull and cascaded Rayleigh with LOS. The level crossing rate and average fading duration are also justified using the measurements. Finally, we extend the work to study Non-Isotropic channels. New models are proposed based on cascaded Rayleigh with NLOS and LOS. We derived its statistical properties similarly to was done for the Isotropic channels. The mean absolute errors was adopted to verify the performance. Power spectrum analysis brought additional insight on this kind of channels.
Thesis (Ph.D.)--Wichita State University, College of Engineering, Dept. of Electrical Engineering and Computer Science