Design and Analysis of Transceiver for Combating Turbulence Induced Fading over Fso Links

In this paper, we investigate the cooperative diversity technique as a candidate solution for combating turbulence induced fading over Free-Space Optical (FSO) links. In particular, a one-relay cooperative diversity scheme is proposed and analyzed for non-coherent FSO communications with intensity modulation and direct detection (IM/DD). The error performance is derived in semi-analytical and closed-form expressions in the presence and absence of background radiation, respectively. Results show the enhanced diversity orders that can be achieved over both Rayleigh and lognormal fading models. In this transceiver design coherent transmitter and receiver design is carried out with the reference to q-ary PPM(pulse position modulation).performance analysis is carried out in all possible strategy.