On the Performance Di erence Between Long and Short Spreading Codes in DS-CDMA Systems

The performance of cellular DS-CDMA systems using long and short spreading sequences is compared in terms of the distribution of the bit error probability, both with and without forward error correction. For the short code case, both conventional and MMSE detectors are considered. The MMSE receiver clearly outperforms both of the conventional receivers. Furthermore, for the conventional receiver, the short code system has a higher performance variability among the user population than the corresponding long code system, which requires attention when designing a short code system. Code hopping as a technique to mitigate this is investigated.