On Propagation Path Loss Models For 3-G Based Wireless Networks: A Comparative Analysis

This paper studies comparatively, the most commonly used path loss models among others, for UMTS based cellular systems, with the goal of reporting through computer simulation, the most reliable one, suitable for efficient coverage planning. We experiment these path loss models using empirical data for macro-cellular (urban) environments. We observe that the Lee path loss model has an improved coverage performance compared to the COST-231 and ECC-33 path loss models respectively. The simulator could generically be adapted for other propagation environments. Third Generation (3G) wireless networks are based on the Universal Mobile Telecommunication System (UMTS) technology and are currently being installed in many countries with the aim of improving upon past technologies and fulfilling users' requirements. The current deployment of UMTS networks is not in many cases ubiquitous and is only concentrated in the congested urban business areas. They are used to provide either the special higher rate data services or increased capacity for handling the voice traffic in specific locations and are therefore complementary and supplemental to the GSM networks. The GSM networks are anticipated to stay around and even continue to grow and expand for at least the next half decade given the huge investments already made by the operators in the GSM infrastructure networks and their fine capability to handle voice, though not with the same spectral efficiency as the Wireless Code Division Multiple Access (WCDMA). This means that the island deployment of UMTS networks will be the trend for some time to come, and hence the requirement for the seamless roaming, handover, and inter-operation with the existing GSM networks to provide service coverage continuity and load sharing. Therefore, the elaborate interoperability and coordination mechanisms and features provided by the equipment need to be exploited by network planners to effectively result in the pooling of the resources, and hence produce the most efficient utilization of the limited expensive radio spectrums. The high throughput and capacity demand of the services anticipated for the 3G networks and the interference-limiting environment of the UMTS based systems require highly skilled radio planning practices and the use of spectral efficiency measures. Signal propagation models are used extensively in network planning, particularly for conducting feasibility studies and performing initial system development (1). The planning of cellular networks requires an understanding of basic concepts concerning the use of Radio signals. The path traveled by the signal from one point to another through or along a medium is called propagation (2). In cellular networks, a signal is propagated to and from a base station. When a signal is transmitted through space, it gets weaker with the distance traveled, resulting in the received power being significantly less than the original transmitted power. This phenomenon is referred to as propagation loss. The propagation path between the transmitter and the receiver may vary from simple line-of-sight (LOS) to very complex one due to diffraction, reflecting and scattering, (3). To estimate the performance of wireless channels, propagation models (4) are often used. The radio wave propagation or path loss models, the properties of the base station and the properties of the mobile station are required to calculate the radio coverage for a chosen base station. Path loss models represent a set of mathematical equations and algorithms which are applied for radio signal