Channel Measurements and Modelling in a Military Cargo Airplane

The results of an ultrawideband (UWB) measurement campaign carried out in a Hercules C-130 military cargo airplane are presented. The environment encompasses several metallic surfaces resulting in a large number of multipath components. Path-loss factor n representing the distance dependence of the channel path-loss is calculated for various frequency centers and bandwidths. A pathgain calculation model based on the concept of seperability of distance and frequency variables is proposed and comparison to measurements is given. Furthermore, time dispersion parameters, namely mean excess delay and root mean square (r.m.s.) delay spread are examined and their dependence on transmitter-receiver antennas separation is investigated. A power law is then employed to model the relation between the number of multipath components and the r.m.s delay spread. The temporal correlation between adjacent path amplitudes is found to be negligible. A modified Saleh-Valenzuela model is invoked to describe the clustering of multipaths, where a different power decay factor is used for the rays of the first cluster as opposed to subsequent clusters. Moreover, the Weibull distribution models the small scale channel fading with a lognormally distributed shape parameter. The average values of this parameter imply severe fading conditions. Finally, simulation results of the proposed statistical model are compared to measured data demonstrating reasonable agreement. Received 6 August 2010, Accepted 17 September 2010, Scheduled 27 September 2010 Corresponding author: A. G. Kanatas ([email protected]). 70 Spiliotopoulos and Kanatas