A Radio Propagation Model for Dense Wireless Networks

Abstract

This paper proposes a model of radio frequency signal propagation in the free space that can be used not only in the far field region of the transmitting antenna like the Friis propagation model for large scale fading, but it can also be employed when the antennas are very close to each other. The modeling starts from a transfer function of the exact two-port network model used to represent the coupling between two antennas in free space. The Z parameter network of the system is used to model the power attenuation as function of the distance between the antennas. Subsequently, a new mathematical model is proposed and compared with the Z parameter network model and shown to have small mean squared error. Such model has the advantage of replacing the Friis formula without the restriction to avoid measuring signals in the near field of the antenna. Furthermore, some practical experiments are carried out in an open field environment and the results are compared. The validity of the new model is demonstrated which can be used for any distance between the antennas and, therefore, it can also be employed to model dense wireless networks.