Enhancing the error performance of optical SSK under correlated channel condition

This paper presents ways of enhancing the performance of spatial shift keying (SSK) in optical wireless communication systems with correlated channel gains. One method involves varying the pulse width and the other involve varying the pulse amplitude to provide additional differentiation to the signal transmitted by each optical source. Closed form expressions are derived for the error performance and are validated with computer based simulations. When compared with the conventional SSK for the correlated channel gains under consideration, these enhancements methods could result in up to 20 dB reduction in signal-to-noise ratio at a symbol error ratio of 10-6 for a four-transmitter, one-receiver configuration.