Sounding techniques for wideband mobile radio channels: a review

A major prerequisite to the specification and design of any wideband digital mobile radio system is a thorough knowledge of the propagation characteristics of the mobile radio channel. The various methods of channel sounding are reviewed, with both narrowband and wideband techniques being discussed. The advantages and limitations of each method are highlighted and the swept time-delay cross-correlator (STDCC) technique is presented as the optimum choice. The main features of an experimental STDCC sounder are identified, factors that are considered essential to good system performance are discussed, and the interrelationships between the sounder parameters are emphasised. It is shown that extension of the power-delay profile prior to calculation of the frequency correlation function leads to the achievement of substantially improved frequency resolution. This is particularly relevant when the average power delay profile contains significant echoes at large excess time delays.<>