Shaping and non-equiprobable signaling for intensity-modulated signals

Da-Shan Shiu, J.M. Kahn
IEEE GLOBECOM 1998 (Cat. NO. 98CH36250)  
The theory of shaping and nonequiprobable signaling, which has been developed for conventional electrical signals, must be modified to treat intensity-modulated (IM) signals. We show that for IM signals, the optimum shape of the constellation bounding region in N -dimensional (N -D) space is an N -D simplex. As N ! 1, the maximum achievable shape gain is 1.33 dB (in terms of transmitted power), and the resulting marginal signaling distribution on the one-dimensional (1-D) constituent
more » ... stituent constellation is exponential. We also investigate the tradeoffs between shaping and its negative consequences, and find that a 1-dB shape gain can be achieved while incurring reasonable increases in peak-to-average power ratio and constellation expansion ratio.
doi:10.1109/glocom.1998.775726 fatcat:my7rhbtnpzgodhuvnwva74wure