State of the art mobile radio channel sounding and data analysis

Radio channel measurements are fundamental for the design of wireless communication networks. As higher data rates are required to provide immersive user experiences and heterogeneous networks are expected to dominate the next generation of cellular networks, multi-band channel sounders are needed to provide the necessary measurements for the design of such systems. In this tutorial the requirements of wideband channel sounding in multiple bands from low frequencies in the TV band to the mmWave band are outlined. Examples of state of the art channel sounder architectures which enable both active radio propagation measurements and passive spectrum monitoring are discussed. Active measurements are enabled through the transmission of a wideband signal using either single or multiple antennas and reception with either single or multiple antennas for the characterisation of multipath parameters such as time delay spread and angular spread. The estimation of path loss and shadowing effects are also enabled through such measurements. As the demand for spectrum efficiency increases, spectrum sensing for cognitive radio applications is increasing in importance. Channel sounders which employ a fast frequency sweep can be used in the passive mode to sense the occupancy of the spectrum and to model and predict the availability of the spectrum in space, time and frequency.