BER Evaluation for Parallel-Relayed Underwater Wireless Optical Communication Systems Over GGD Oceanic Turbulence

In this paper, the average bit-error-rate (BER) performance of a two-hop parallel-relayed underwater wireless optical communication (UWOC) systems with on-off keying (OOK) was analyzed in generalized gamma distribution (GGD) oceanic turbulence. First, a hybrid fading channel model that includes GGD oceanic turbulence, and fading free impulse response (FFIR) implicit path loss plus multipath effect was proposed; Subsequently, the mathematical closed-form expressions of the average BERs of the parallel-relayed UWOC systems with equal gain combining (EGC) at the destination node under the proposed hybrid fading were derived in detail by using the higher transcendental Fox-H function. Theoretical analysis and numerical simulation results show that the introduction of parallel relaying nodes and combining receiving can effectively improve the BER performance of the UWOC systems especially in a long-distance communication environment. Moreover, the average end-to-end BER curves of the UWOC systems calculated by the derived closed-form formulas have nearly the same changing trends and little performance gap compared with that obtained through Monte Carlo computer simulations.