CTH12-3: Gaussian Chip Waveform Together with Markovian Spreading Codes Improve BER Performance in Chip-Asynchronous CDMA Systems

Performance of chip-asynchronous DS/CDMA system depends on chip waveform as well as spread spectrum (SS) codes. In case of rectangular chip waveform, SS codes generated by a Markov chain were shown to improve bit error rate (BER) performance. However, in commercial CDMA systems, a band-limited root raised cosine (RRC) pulse is used, where the superiority of Markov codes is reduced. RRC pulse fulfills inter-chip interference (ICI)-free condition. In CDMA systems, multiple-access interference (MAI) is of crucial importance. Gaussian pulse used in conjunction with Markovian codes reduces MAI although it does not has the ICI-free property. Computer simulations show that Gaussian pulse with same excess bandwidth energy as the RRC pulse significantly reduces BER.