Non-binary LDPC-coded modulation for high-speed optical metro networks with backpropagation

Abstract

To simultaneously mitigate the linear and nonlinear channel impairments in high-speed optical communications, we propose the use of non-binary low-density-parity-check-coded modulation in combination with a coarse backpropagation method. By employing backpropagation, we reduce the memory in the channel and in return obtain significant reductions in the complexity of the channel equalizer which is exponentially proportional to the channel memory. We then compensate for the remaining channel distortions using forward error correction based on non-binary LDPC codes. We propose non-binary-LDPC-coded modulation scheme because, compared to bit-interleaved binary-LDPC-coded modulation scheme employing turbo equalization, the proposed scheme lowers the computational complexity and latency of the overall system while providing impressively larger coding gains.

Rate-Adaptive nonbinary-LDPC-coded modulation with backpropagation for long-haul optical transport networks

“…We particularly targeted long-haul optical communication links with reaches exceeding thousands of kilometers. For comparatively shorter-reach applications such as optical metro networks, we refer the interested readers to [7]. We considered QPSK, 8-SQAM and 16-SQAM modulation formats which resulted in a minimum of 200, 300 and 400 Gb/s aggregate information bit rates.…”