The numerical solution of the partial differential equation (PDE) of the received signal strength from fixed transmitting stations as derived from Maxwell’s wave equation is presented in this paper. The received signal strength level (RSSL) at a defined distance from a source point (base transceiver station) was simulated for two real environments described as Sites 1 and 2. The values of RSSL were taken at different nodes and at different radial directions away from the source point using the Finite Element Method (FEM) tool of the MATLAB package. The hexagonal geometry with no describing function was assumed for the cell. A 3-D model of the power received versus distance was obtained, and the numerical solution of the model presented. The numerical results obtained from the 3-D model were compared with the results of the drive test conducted in Sites 1 and 2 for functional GSM radio networks in the areas. The suitability of the method was justified for the two sites with a 5.55dB standard deviation of error for network A in Site 1 and 8.36dB and 3.40dB standard deviations of error for networks A and B respectively for Site 2.