Analysis of non-coherent code tracking for NPSK systems in presence of noise and fading

Given the recent interest in non-binary forms of spreading sequences, there is a gap in knowledge on code tracking techniques for noise-like spreading codes. This paper presents theoretical analysis and simulation results for non-coherent code tracking systems that employ the Noise Phase Shift Keying scheme. The theoretical analysis has been presented considering the channel is hindered by noise as well as slow Rayleigh fading. The effect of slow fading is reflected in the theoretical analysis and it is confirmed that the analytical results will simplify to the noise only case if the effect of Rayleigh fading is lifted. The theoretical control law for non-coherent code tracking for Noise Phase Shift Keying is also presented. The theoretical findings are verified by simulation results in terms of instantaneous and cumulative tracking estimation as well as tracking loop S-curves.