Optical CDMA using 2-D codes: the optimal single-user detector

We consider the error performance of an optical code-division multiple access network in which two-dimensional codes are generated in time and wavelength. We show from first principles that the optimum single-user detection scheme which yields is the AND detector. By replacing the widely considered SUM detector with the AND detector, the channel capacity can be at least doubled for a given data rate, number of active users, and bit error rate. We have also shown that the error performance of a random code gives a tight upper bound on the performance of deterministic code with the same weight and dimension.