Linear Polarization Division Multiplexing Based Optical Wireless Communication Incorporating Improved DSP

Digital signal processing (DSP) is essential for realizing the full potential of multilevel modulation schemes in communication systems. It ensures that signals are reliably detected, corrected, and optimized for various channel conditions, making it possible to achieve higher data rates, improved spectral efficiency, and enhanced overall performance in modern communication networks. In this work, an improved DSP is introduced in the receiver of linear polarization division multiplexed (LPDM) 256-quadrature amplitude modulation (256-QAM) supporting inter-satellite optical wireless communication (IsOWC). Gram-Schmidt orthogonalization procedure (GSOP), time-domain equalization algorithm (TEDA), improved Viterbi algorithm (IVA), and least mean square (LMS) algorithms are employed in improved DSP. The proposed system is compared with the 256-QAM/conventional DSP (CDSP), and LPDM-256QAM/CDSP in terms of log BER. Results revealed that proposed system is highly efficient and covered 26,000 km at 160 Gbps in comparisons to 21,000 using 256-QAM/CDSP and 22,000 with LPDM-256-QAM/CDSP.