Enhancement of Constant Amplitude Coding for Multicode Wideband CDMA Systems

Su Il KIM  Gill Young JUNG  Soon Young YOON  Hwang Soo LEE  

IEICE TRANSACTIONS on Communications   Vol.E83-B   No.11   pp.2550-2555
Publication Date: 2000/11/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Wireless Communication Technology
muticode wideband CDMA,  constant amplitude transmission,  HPA,  peak-to-average power ratio,  PAPR,  

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A constant amplitude transmission scheme for multicode wideband CDMA systems is proposed. Multicode wideband CDMA systems result in large amplitude fluctuation because the multicode signal is the sum of constituent code channel signals. This large amplitude fluctuation brings out large non-linear distortion and then, if unaccounted, can significantly degrade the bit error rate (BER) performance. Constant amplitude transmission, achieved by using a Walsh code and parity generator, is proposed to combat the large amplitude fluctuation and reduce the peak-to-average power ratio (PAPR). Unlike other constant amplitude transmission scheme, the proposed scheme does not use a redundant code channel. Computer simulation results show that the proposed scheme improves BER performance significantly and that the proposed scheme is extremely effective to the non-linear distortion of high power amplifier (HPA).