Sensitivity of the System Performance to the Propagation Parameters in LOS Microcellular Environments

Propagation loss is a fundamental phenomenon that affects the performance of any wireless network. Although propagation characteristics in line-of-sight (LOS) microcellular systems are well known, so far, only a few papers have investigated its effect on system performance in a comprehensive manner. In this paper, the impact of both system parameters (i.e., cell size, antenna height, operating frequency, and reuse factor) and propagation loss parameters (i.e., breakpoint distance, path loss exponents, standard deviation of the shadowing component, signals correlation, and effective road height) on the performance of both time-division multiple access (TDMA)- and code-division multiple access (CDMA)-based LOS microcellular networks is studied. Performance is evaluated in terms of outage probability in TDMA-based systems and in terms of the other-cell interference factor in CDMA-based systems. This paper includes substantial numerical results and new insights into the behavior of wireless system performance. For instance, novel insights into the impact of both distance-dependent shadowing and the effective road height on system performance are provided. In particular, nontypical fluctuational and discontinuous behavior on performance metrics are observed, and at microwave frequencies, the spectral efficiency is greater for heavy vehicular traffic conditions (i.e., during daytime) than for light vehicular traffic conditions (i.e., during nighttime). Such an understanding of interference engineering issues is vital for the planning, designing, dimensioning, and the optimization of mobile LOS microcellular networks for present and future wireless systems beyond third generation.