Coding and modulation for the additive exponential noise channel

Communication across an additive exponential noise (AEN) channel is studied. Constellations are designed for low signal-to-noise ratio, where the minimum energy per bit is not universally attained by all modulations, and for high signal-to-noise ratio, where an equiprobable non-uniform constellation 0.76 dB away from capacity is described. The pairwise error probability for binary codes is similar to that in an equivalent discrete-time Gaussian channel of identical signal-to-noise ratio.