Average channel capacity analysis of BDF relaying over alpha-mu fading channels

Average channel capacity for the bit-detect-and-forward (BDF) cooperative protocol over α-μ fading channels is analyzed. Novel closed-form approximate ergodic capacity expression is here obtained for a 3-way free-space optical (FSO) communication setup when the irradiance of the transmitted optical beam here considered is susceptible to moderate-to-strong turbulence conditions, following a gamma-gamma (GG) distribution of parameters a and b, or pointing error effects, following a misalignment fading model where the effect of beam width, detector size and jitter variance are considered. Moreover, we present novel asymptotic expressions at high signal-to-noise ratio (SNR) by using the asymptotic expansion of H-fox function as well as at low SNR for the ergodic capacity of BDF cooperative protocol. A greater and robust capacity is achieved compared to a direct path link without cooperative communication when line of sight is available.