A plausible approach to determine most suitable spreading codes for a direct-sequence CDMA system


Ciftlikli C., Develi I.

KUWAIT JOURNAL OF SCIENCE & ENGINEERING, cilt.31, ss.235-259, 2004 (SCI İndekslerine Giren Dergi) identifier

  • Cilt numarası: 31 Konu: 2
  • Basım Tarihi: 2004
  • Dergi Adı: KUWAIT JOURNAL OF SCIENCE & ENGINEERING
  • Sayfa Sayısı: ss.235-259

Özet

It is well known that the exponential chip weighting waveforms used in a direct-sequence/eode-division multiple aceess (DS/CDMA) receiver are designed for the purpose of multiple access interference (MAI) rejection based on the concept that the despreading sequence emphasizes the transitions in the received spreading sequence of interest. In this study, it is observed that better bit error rate (BER) performances might be achieved for a DS/CDMA system which employs exponentially weighted despreading sequences by selecting proper codes as references in a given code set. A plausible approach is introduced to determine the spreading codes which are most suitable to use as references in a code assignment process. Throughout this study, it is assumed that the receivers are perfectly capable of regenerating the transmitted codes corresponding to each of the users' transmissions and as such all synchronization issues are ignored. The accuracy of the proposed approach is tested on various code sets having different code lengths. Numerical results show that the approach presented in this work could distinguish the most suitable reference spreading codes in a given code set precisely.
It is well known that the exponential chip weighting waveforms used in a direct-sequence / code-division multiple access (DS/CDMA) receiver are designed for the purpose of multiple access interference (MAI) rejection based on the concept that the despreading sequence emphasizes the transitions in the received spreading sequence of interest. In this study, it is observed that better bit error rate (BER) performances might be achieved for a DS/CDMA system which employs exponentially weighted despreading sequences by selecting proper codes as references in a given code set. A plausible approach is introduced to determine the spreading codes which are most suitable to use as references in a code assignment process. Throughout this study, it is assumed that the receivers are perfectly capable of regenerating the transmitted codes corresponding to each of the users’ transmissions and as such all synchronization issues are ignored. The accuracy of the proposed approach is tested on various code sets having different code lengths. Numerical results show that the approach presented in this work could distinguish the most suitable reference spreading codes in a given code set precisely.