The performance of a DLL based code tracking algorithm in a realistic CDMA land mobile satellite channel

Abstract

The performance of a non-coherent DLL based code tracking algorithm for CDMA land mobile satellite systems under realistic channel conditions is studied by computer simulations. In this study the channel models used correspond to LEO satellite systems, which are typically influenced by extremely high Doppler effects due to the relatively high speed of satellite movement. Four different channel conditions were considered: good urban, bad urban, light shadowed rural and medium shadowed rural state. To get the insight of the performance of the code tracking algorithm the mean and standard deviation values of steady state code tracking errors were calculated. Also the convergence time of the recovered code phase from initial code phase error of 0.5 chips was calculated. According to the simulation results the performance of the non-coherent DLL as a code tracking algorithm was found to be satisfactory in realistic mobile satellite channel.