BER performance of multiplexed CSK using linear/circular polarization in optical wireless communications

In this paper, Bit Error Rate (BER) performance of polarization multiplexed Code Shift Keying (CSK) in optical wireless communications is analyzed. The authors consider the linear polarization and the circular polarization for polarization multiplexing. They use Pseudo-Orthogonal M-Sequence pairs as the sequences for CSK and investigate a case where each polarization uses a mutually orthogonal sequence for CSK. They analyzed BER performance taking mismatch of the transmission axis directions between transmitter and receiver, and polarization change which occurs in the transmission channel, in to account. Consequently, they showed that mismatch of the transmission axis directions significantly affects the linear polarization system, and polarization change in the transmission channel significantly affects the circular polarization system.