Demodulator quantization of coded OOK FSO systems over atmospheric turbulence channels

This paper addresses a practical aspect of coded on-off keying free-space optical communication systems: quantization of demodulator outputs in receiver. Receivers with and without knowledge of channel state information (CSI) are considered. Proposed quantization schemes for soft decision decoding with CSI are uniform with quantization intervals proportional to channel gains. The schemes are studied and compared under the criterion of the cut-off rate of the discrete channel created by quantization.