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/.
[1]
Robert C. Harney,et al.
Burst-mode atmospheric optical communication
,
1980
.
[2]
John G. Proakis,et al.
Digital Communications
,
1983
.
[3]
R. S. Lawrence,et al.
A survey of clear-air propagation effects relevant to optical communications
,
1970
.
[4]
Joseph M. Kahn,et al.
Free-space optical communication through atmospheric turbulence channels
,
2002,
IEEE Trans. Commun..
[5]
L. Andrews,et al.
Laser Beam Propagation Through Random Media
,
1998
.
[6]
Masao Nakagawa,et al.
Atmospheric optical communication system using subcarrier PSK modulation
,
1993,
Proceedings of ICC '93 - IEEE International Conference on Communications.