Error analysis for a hybrid DS/TH impulse radio UWB multiple access system

A hybrid direct-sequence time-hopping (DS/TH) impulse radio (IR) ultra-wideband (UWB) multiple access system is proposed and a simple error analysis is presented for the system. The error analysis facilitates to obtain simple-to-evaluate and accurate error probabilities based on Holtzman´s simplified improved Gaussian approximation (SIGA), a method that has previously mainly been used in DS-CDMA. In this paper, we show that the method can also be used effectively for IR UWB multiple access systems that use signals of low duty-cycle. It is shown that despite having the same processing gain, which is the multiplication of the number of frames per bit and chips per frame, different combinations of the parameters result in different performances. System performances are presented for various duty-cycles of the signals considering equal and unequal powers of the users and the validity of standard Gaussian approximation (SGA) is examined at those situations. The theoretical results are validated by Monte Carlo simulations.