An orthogonal space-time block code with Q-PPM modulation

Orthogonal space-time block code (OSTBC) can greatly improve transmit speed rate and mitigate the effect caused by atmospheric turbulence, furthermore it can reduce the error rate in the wireless optical communication system. In this paper, the model of the multiple input multiple output (MIMO) wireless optical communication about the Gaussian channel is proposed. And an orthogonal space-time block codes using pulse position modulation (PPM) is advised. Then the maximum likelihood decision rule and the symbol error probability (SEP) is deduced. At last, the feasibility of this technique is proved by simulation experiment, and moreover our code is compared with the complement orthogonal space-time block code (COSTBC). The experiment results show that our code is an effective fading-mitigation technique to overcome scintillation effect and can achieve the 1 speed rate transmission in free space optical communication system.