3. Propagation Prediction of Electromagnetic Waves in Outdoor Environments.

P.Thirumaraiselvan, R.Rameshkumar and V. Jayavardhanavelu

To achieve optimum performance of a wireless communication system, understanding of the propagation channels is necessary. Even though accurate evaluation of onsite performance is possible with direct measurements, it requires a considerable amount of time and efforts.
Therefore, a computer tool that could characterize the wireless channel from the building plans and material properties would be a good solution. This paper considers an approach for developing such a simulation tool for propagation prediction of electromagnetic waves in an outdoor environment and to predict the path loss characteristics. The simulator has been implemented in Matlab. The electromagnetic waves are modelled as rays, assuming that the scattering objects are much larger than their wavelength. Rays are launched from the transmitter in all directions. Interactions of rays with the surroundings, i.e. specular reflections and transmissions, are tracked using a three dimensional shoot-and-bounce ray tracing technique. At the receiver, reception sphere is used to check for signal reception. A ray is said to be received if it intersects the properly sized reception sphere. From the results of ray tracing, received field strength is computed based on the theory of Geometrical Optics.