Synchronous CDMA for Optical Subscriber Systems Using Block-Interleave and Redundancy Code Sequences

Tetsuya ONODA  Noriki MIKI  

IEICE TRANSACTIONS on Communications   Vol.E76-B   No.8   pp.969-983
Publication Date: 1993/08/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Spread Spectrum Techniques and Applications)
spread spectrum,  CDMA,  optical subscriber network,  point to multi-point,  multi-point multiplexing,  block-interleave,  

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A new type of synchronous code division multiple access (S/CDMA) scheme for optical subscriber systems is reported. Passive channel multiplexing is promising for optical subscriber systems because it realizes high system performance at low cost. Unfortunately, passive channel multiplexing suffers from phase differences among the upstream channels, and these differences prevent the usage of traditional synchronous CDMA techniques that reduce cross channel interference. This paper proposes the new technique of block-interleaving & redundancy code sequences to overcome this problem. This combination realizes S/CDMA even in the presence of phase differences and eliminates cross channel interference completely. Therefore, in an optical subscriber system using the new type S/CDMA, the bit error rate performance is independent of phase difference levels and the number of multiplexed channels.