PERFORMANCE OF MULTIUSER DETECTION FOR OPTICAL CDMA .1. ERROR PROBABILITIES

Characterization of optimum multiuser performance in intensity-modulat ion direct-detection optical CDMA channels is addressed. Analysis is b ased on some simple bounds on optimum performance provided by receiver s with side-information or by a linear ''decorrelating'' receiver. Num erical comparisons of the performance bounds are obtained via applicat ion of saddlepoint approximations to the multiuser photocount statisti cs. General analytical relations comparing these approximations to sim ilar asymptotic approximations based on the Chernoff-bound are also de rived. The numerical results illustrate the fundamental importance of two of the performance bounds, which are shown to be asymptotically ti ght in Part II of this paper. In addition, the numerical error probabi lity results verify the relevance of the asymptotically-based performa nce analysis for optical CDMA in Part II.