Performance analysis for optical wireless communication systems using subcarrier PSK intensity modulation through turbulent atmospheric channel

This paper compares the performance of on-off keying (OOK) modulation and subcarrier phase shift keying (PSK) modulation through an optical wireless channel. The bit error rate (BER) for a turbulent channel is derived for optical wireless communication systems employing OOK or subcarrier BPSK. A lower bound is derived for BER performance when fixed-threshold OOK is used. It is also shown that the BER performance of the optical wireless communication system, employing subcarrier PSK modulation, is more than 3 dB better than that of a compatible system employing fixed-threshold OOK modulation at BER=10/sup -6/ and with turbulence parameter /spl sigma/=0.1. When /spl sigma/ is 0.2 and fixed-threshold OOK is employed, the BER performance never falls down to 10/sup -4/. The BER performance degradation of optical wireless communication systems employing subcarrier BPSK between /spl sigma/=0.1 and /spl sigma/=0.2 is only 2.5 dB at BER=10/sup -6/.