Gaussian chip shaping enhances the superiority of Markovian codes in DS/CDMA systems
Yutaka Jitsumatsu, Tohru Kohda · 2006
It is known that spreading codes generated by a Markov chain improve bit error rate performance of direct sequence/code division multiple access (DS/CDMA) systems if the chip pulse is rectangular. Real analysis tells us that a pair of the rectangular and sine functions is one of Fourier transform and its inverse Fourier transform and vice versa. On the other hand, Gaussian pulses have the self-duality property: they have the same expression in both time and frequency domains. Gaussian chip pulses sacrifice inter-symbol interference. However, the use of Markovian codes together with a Gaussian pulse increases the system performance approximately 30% in terms of the number of users