Performance analysis and comparison of optical IDMA and optical CDMA techniques using unipolar transmission scheme

Interleave-division multiple-access (IDMA) has been recently proposed as a new spread spectrum multiple-access technique in optical communication systems. However, IDMA has not been studied for intensity modulation/direct detection (IM/DD) optical networks. In this paper, we introduce modifications to traditional IDMA decoding algorithm so as to make it suitable for IM/DD optical communication systems. In addition, we compare the performance, in terms of the bit-error rate (BER), of optical IDMA systems to the corresponding systems adopting optical CDMA. Our results reveal that under the above modifications, optical IDMA systems show significant improvement in the BER performance when compared to that of optical CDMA systems under same conditions.