Capacity of DS-CDMA versus TH-PPM for Multi-User Ultra-Wideband Systems

This paper focuses on the channel capacity of direct sequence code division multiple access (DS-CDMA) and time-hopping pulse position modulation (TH-PPM) for ultra-wide band (UWB) communication systems over multiple-access and additive white Gaussian noise (AWGN) channel. Based on Gaussian approximation for the multiple access interference, an expression of the signal-to-noise ratio is derived for the UWB system using 2nd derivative Gaussian pulse. The information theoretic capacity of the UWB system is expressed as a function of system parameters. Analytical and simulation results show that the capacity of DS-CDMA outperform the capacity of TH-PPM UWB system for high demand environment