Non-coherent UWB receiver for multi-level spectrally-encoded spread-time CDMA systems

Nowadays, ultra-wideband (UWB) communication systems are in focus because of their attractive features such as high capacity, low power consumption and robustness against fading. On the other hand, spectrally-encoded spread-time (SE/ST) systems with superior ability on interference suppression provide proper multiuser efficiency over UWB channels. Coherent SE/ST code division multiple access (CDMA) systems are widely addressed in the literature requiring accurate channel estimation and high implementation complexity. In this paper we propose multi-level SE/ST CDMA system with non-coherent detection and simple receiver structure. Our results demonstrate the effect of signal to noise ratio (SNR), code length and total number of users on the performance. We find some optimum values for code length minimizing the probability of error. Simulation results support the precision of our analytical derivations.