Exact error rate analysis of equal gain and selection diversity for coherent free-space optical systems on strong turbulence channels

Abstract

Exact error rate performances are studied for coherent free-space optical communication systems under strong turbulence with diversity reception. Equal gain and selection diversity are considered as practical schemes to mitigate turbulence. The exact bit-error rate for binary phase-shift keying and outage probability are developed for equal gain diversity. Analytical expressions are obtained for the bit-error rate of differential phase-shift keying and asynchronous frequency-shift keying, as well as for outage probability using selection diversity. Furthermore, we provide the closed-form expressions of diversity order and coding gain with both diversity receptions. The analytical results are verified by computer simulations and are suitable for rapid error rates calculation.

Terrestrial Coherent Free-Space Optical Communication Systems

“…A statistical model was developed in [49] considering spatial phase noise with log-normal turbulence and analyzed for capacity evaluation [50], [51]. In [52] and [53], the error rate performance of coherent FSO systems with MRC, EGC, and selection diversity reception in strong turbulence regions was studied. Spatial diversity techniques have been shown to be effective in mitigating the atmospheric turbulence-induced fading.…”

“…Thus, in a coherent FSO communication system, using the fact that the photocurrent from the receiver is the product of the responsivity R and incident optical power, we write the detected photocurrent from Fig. 1 as [53] …”

Field Conjugation Adaptive Arrays in Free-Space Coherent Laser Communications

“…R ecent advances in coherent optical communications in fiber transmission systems [1] have stimulated interest in applying coherent detection in free-space laser communications (see, e.g., [2][3][4][5][6][7][8][9]). In a coherent system, transmitted information can be encoded in the complex electric field, including amplitude, phase and polarization.…”

Digital equalization of time-delay array receivers on coherent laser communications

“…In general, given a fixed collecting area, the performance of the array should improve with an increasing number of apertures [3][4][5][6].…”