Performance analysis of atmospheric optical PPM CDMA systems

We propose atmospheric optical code-division multiple-access (CDMA) systems. We analyze the bit-error rate of the proposed system using pulse-position modulation (PPM) with considering the effects of the scintillation, avalanche photodiode noise, thermal noise, and multi-user interference. We show that the atmospheric optical CDMA systems can realize high-speed communications when the logarithm variance of the scintillation is small. When (sigma)/sub s//sup 2/ is large, we need to use forward-error correction codes.