Lessons Learnt through using a Physics Based Macro Model for Analysis of Radio Wave Propagation in Wireless Transmission

This paper summarizes the lessons learnt in using a physics based macro model in studying electromagnetic wave propagation over an imperfectly conducting ground in cellular wireless communication. Firstly, it has ben observed that the path loss exponent is independent of the nature of the ground parameters inside the cell of interest. Secondly, the electrical parameters of the environment have little effect on the path loss exponent in the cellular band. Thirdly, it is observed that lowering the base station antenna towards the ground provides a larger signal in the near field within the cell of interest. Furthermore, tilting the transmitting antenna towards the sky enhances the signal strength. Tilting the antenna towards the ground increases the signal strength but in addition enhances the interference pattern and hence is not a good solution. A typical path loss inside the cell is 30 dB per decade of distance and outside the cell it increases to 40 dB per decade. By bringing the antenna closer to the ground and then tilting it towards the sky provides a good non intuitive solution. In such scenarios, a path loss of 20 dB per decade for some components of the field, the lowest possible, can be achieved for certain orientation and deployment of the base station antenna. In addition, it is shown that operating an antenna inside a metallic box eliminates its radiation capabilities and hence has no physical meaning even though it is claimed in the contemporary literature that it simulates a rich multipath environment. Lastly, a note on the proper interpretation of the term channel capacity and its implications are delineated.