Propagation in cellular networks

Received signal level measurements are frequently used to check the performance and the Quality Of Service (QOS) inside the coverage area in cellular networks. These expensive time consuming measurements are carried out using actual drive tests to assess the coverage area of a base station for a given cell and thus evaluate the QOS. In a drive test measurement system, a receiving antenna is placed on top of a vehicle and the vehicle is then driven along radial and circular lines around the base station to measure the received power and thus assess the QOS. These drive test measurements are also used to tune the empirical models in the radio planning tools which have to be carried out for various types of environments. In this paper, it is shown that an electromagnetic macro modeling of the environment can provide simulation results comparable to the data as one would obtain in an actual drive test measurement for a cellular environment. The input parameters for the electromagnetic macro model can be generated using only the physical parameters of the environment like the height of the transmitting and receiving antennas over the ground, their tilts towards the ground, and the electrical parameters of the ground. Such analysis can provide realistic plots for the received power versus separation distance between the receiving and the transmitting base station antennas without any statistical or empirical curve fitting or an adhoc choice of a reference distance. A method of moments-based integral equation solver code has been used to simulate the effects of the macro parameters of the environment on the propagation path loss of the signals emanating from a base station antenna. This code is based on Sommerfeld Green's function to treat the imperfectly conducting planar ground.