Identification of LOS and NLOS for wireless Transmission

Distinguishing the transmission status of the communication as line-of-sight (LOS) and non-LOS (NLOS) is of great importance for the wireless communication systems. It is known that for LOS and NLOS, some statistical characteristics of the transmission differ from each other. If the distinction between LOS and NLOS can be made as quick and accurate as possible, ranging based applications and adaptive radio systems like cognitive radios can make use of this information to increase their performances significantly. In this study, a numerical and computationally low complex method for coherent receivers is proposed to discriminate the LOS/NLOS status of the transmission depending on the autocorrelation properties of individual paths. The proposed method is tested for both noise-free and noisy conditions with sum-of-sinusoids (SoS) and inverse discrete Fourier transform (IDFT) based simulation models. It is observed that the proposed method gives good results even for relatively low signal-to-noise ratio (SNR) values