A novel method for increasing the spectral efficiency of optical CDMA

Stefano Galli, Ronald Menendez, Russel Fischer, Robert J. Runser, Evgenii Narimanov, Paul R. Prucnal

Research output: Chapter in Book/Report/Conference proceedingConference contribution

11 Scopus citations


Given K users simultaneously active, an Optical CDMA (OCDMA) receiver needs to discriminate among K codes. Since the number of available codes C is always C≫K at any given time for an asynchronous OCDMA system employing quasi-orthogonal codes, there is always a set of unused codes and these codes can be exploited to increase the spectral efficiency of the system. This can be accomplished by exclusively assigning to each user a set of M codes which represent a log2(M)-tuple of bits so that each user effectively uses a multidimensional modulation (multiple information bits per code are conveyed). In this paper, we analyze the performance of such a system, and find that an upper bound on the probability of error can be expressed in terms of the performances of the conventional case where one code only per user is employed. Moreover, we also find that, under certain conditions, the multidimensional modulation here proposed allows us to obtain higher spectral efficiency, higher power efficiency, and lower bit-error rate (BER) than conventional OCDMA, which employs one code per user.

Original languageEnglish (US)
Title of host publicationGLOBECOM'05
Subtitle of host publicationIEEE Global Telecommunications Conference, 2005
Number of pages5
StatePublished - 2005
EventGLOBECOM'05: IEEE Global Telecommunications Conference, 2005 - St. Louis, MO, United States
Duration: Nov 28 2005Dec 2 2005

Publication series

NameGLOBECOM - IEEE Global Telecommunications Conference


OtherGLOBECOM'05: IEEE Global Telecommunications Conference, 2005
Country/TerritoryUnited States
CitySt. Louis, MO

All Science Journal Classification (ASJC) codes

  • General Engineering


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