Channel Coding Gains in High Throughput and Long Reach Optical Transmission Systems

Abstract

— The main objectives of the project is the investigation of two main types of coding schemes with the aim of maximizing optical signal to noise ratio (OSNR) gains in long reach optical transmission systems. The project will start with a study of the various coder/decoder schemes followed by the identification of the main types e.g. direct mapping schemes and/or Trellis Coded Modulation schemes for Quadrature Phase Shift Keying (QPSK). Trellis coded modulation (TCM) and parallel concatenated (PC)-TCM. A TCM encoder and decoder were created and its performance simulated for bit error rate (BER) against various signal to noise ratio (SNR) measurements. A sequence for the setup was created, transmitted and successfully decoded. A TTCM encoder and decoder were created. Further tuning is needed for the TTCM decoder However, implemented coders also require investigation and implementation of algorithms required for the decoders (e.g. Viterbi and Forward backward algorithm). Finally, the implemented encoder/decoder schemes are evaluated in an 112Gbit/s QPSK/8PSK single mode fiber recirculating loop setup for BER and OSNR validation