DS-OCDMA receivers based on parallel interference cancellation and hard limiters

• Published in: IEEE transactions on communications Vol. 54; no. 9; pp. 1663 - 1671
• Main Authors: Goursaud, C., Julien-Vergonjanne, A., Aupetit-Berthelemot, C., Cances, J.-P., Dumas, J.-M.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-09-2006; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Cancellation; Codes; Coding, codes; Detection, estimation, filtering, equalization, prediction; Error probability; Errors; Exact sciences and technology; Hard limiter (HL); Hardware; High speed optical techniques; Information, signal and communications theory; Integrated optics; Interference; Interference cancellation; Multiaccess communication; Multiple access interference; multiple-access interference (MAI); optical code-division multiple access (OCDMA); Optical noise; optical orthogonal codes (OOCs); Optical receivers; Optical signal processing; Optical telecommunications; parallel interference cancellation (PIC); Permissible error; Receivers; Signal and communications theory; Signal, noise; Synchronous; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Transmission and modulation (techniques and equipments); Upper bounds; Performance evaluation; Multiple access; Error probability; Noise reduction; Bit error rate; Optical telecommunication; Wireless telecommunication; optical orthogonal codes (OOCs); Interference suppression; Signal interference; Orthogonal code; multiple-access interference (MAI); optical code-division multiple access (OCDMA); Code division multiple access; Parallel processing; Signal processing; Hard limiter (HL); Direct sequence; parallel interference cancellation (PIC); Limiter
• ISSN: 0090-6778; 1558-0857
• DOI: 10.1109/TCOMM.2006.881252

In an incoherent direct-sequence optical code-division multiple-access (DS-OCDMA) system, multiple-access interference (MAI) is one of the principal limitations. To mitigate MAI, the parallel interference cancellation (PIC) technique can be used to remove nondesired users' contribution. In this paper, we study four DS-OCDMA receivers based on the PIC technique with hard limiters placed before the nondesired users or before the desired user receiver, or both. We develop, for the ideal synchronous case, the theoretical upper bound of the error probability for the four receivers. Significant performance improvement is obtained by comparison with conventional receivers in the case of optical orthogonal codes. The paper highlights that the number of active users with null error probability is doubled, compared with conventional receivers. Finally, we show that, thanks to their good performances, the PIC structures permit considerably reducing the minimal code length required to have 30 users with bit-error rate <10 -9 . So, the hardware constraints are relaxed for realistic application