Systems and methods for data transport are provided which encode streams of data using low density parity check (LDPC) encoders and map data streams to symbols, by assigning bits of symbols to a signal constellation and associating bits with constellation points. Constellation points are generated using a D-dimensional optimum signal constellation design (OSCD) method. The OSCD determines an optimum source distribution for an optical channel, generates D-dimensional training sequences from the optimum source distribution, determines new signal constellation points as the center of mass for each D-dimensional cluster of points, and repeats these steps until convergence or until a predetermined number of iterations is reached. Coordinates obtained by the D-dimensional OSCD method are stored in a look-up-table (LUT), points are selected from the LUT using encoded data streams, coordinates are input into a D-dimensional modulator after digital-to-analog conversion (DAC), and a modulated signal is transmitted over an optical medium.