Systems and methods for data transport, including encoding streams of input data using generalized low-density parity check (GLDPC) encoders, the one or more GLDPC encoders being configured to generate GLDPC coded data streams using a plurality of component local codes to improve error correction strength, employ single-parity checks and two or more local block codes during generation of the GLDPC codes, and enable continuous tuning of code rate using the generated GLDPC codes. Signals may be generated using mappers, the mappers configured to assign bits of signals to signal constellations and to associate the bits of the signals with signal constellation points. The signal may be modulated using an I/Q or 4-D modulator composed of one polarization beam splitter, two I/Q modulators, and one polarization beam combiner. The modulated signals are multiplexed using a mode-multiplexer, transmitted over a transmission medium, and the signals are received and decoded using GLDPC decoders.