Impact of a Concrete Room on the Performance of Cellular Telephone Communications for Low Bit Rate Applications

In this paper, a new propagation model, in macrocellular wireless communication systems, is derived. The model characterizes the base station to mobile radio channel when the propagated signal is being obstructed by lossy concrete room in which the mobile phone moves. The analysis is performed by using ray-tracing techniques combined with uniform theory of diffraction (UTD), in addition to using a UTD modified heuristic diffraction coefficient for non-perfectly conducting wedges. The maximum considered ray reflections are three, single and double diffractions are also considered in this study. Therefore, all expected significant ray contributions in multipath channel are included. These rays include direct, reflected, refracted and diffracted paths, or any combination of the mentioned paths. The mathematical propagation model is derived, after which the model is implemented by different computer programs written in Matlab. For low bit rate applications (narrowband systems), the attenuation and fading of the propagated signal are the main causes of signal degradation. Therefore, the signal strength, as a function of mobile location inside the room, was computed for base station with an antenna array. The depolarization effect on propagated signal as well as the cumulative distribution function (CDF) and probability density function (PDF), that are useful for statistical prediction models, are studied. Details of the present model that may facilitate implementation are given. Comparison with measurements revealed acceptable agreement. The results of this research work should be useful in radio link design of macrocellular land mobile communication systems.