Particle Filter Based Joint STTC Decoding and Blind Estimation for Free Space Optical Communication

In order to restrain the influence from atmosphere turbulence and channel time-varying character on free space optical communication system, a novel universal scheme with transmitting diversity and receiving diversity is put forward, into which STTC is introduced to fully make use of the characteristic of spatial diversity and time diversity. In order to reducing the decoding complexity, a modified particle filter is adopted, and trellis codeword structure is fused into the importance distribution of particle Alter to decode with joint maximum posterior distribution. Monte Carlo simulation indicates that STTC based on particle filter can effectively decrease the mean BER, greatly improve the channel capacity, and nearly approach to the optimal BER performance with the minimum complexity.