Multidimensional coded-modulation for high-speed optical transport over few-mode fibers

摘要

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.

主权项

1. A method for optical data transport, comprising:
formulating a signal constellation using a D-dimensional optimum signal constellation design (OSCD) method, wherein D is an integer, the method comprising including: determining a D-dimensional optimum source distribution for a given optical channel using an Arimoto-Blahut algorithm; generating D-dimensional training sequences from the optimum source distribution, with the D-dimensional training sequences being split into D-dimensional clusters of points; determining new signal constellation points as the center of mass for each D-dimensional cluster of points; and repeating the formulating steps until convergence or until a predetermined number of iterations has been reached; encoding one or more streams of input data using one or more low density parity check (LDPC) encoders; mapping one or more encoded data streams to symbols, wherein a mapper is configured to assign bits of the symbols to one signal constellation and to associate the bits of the symbols with signal constellation points; generating signal constellation points using a D-dimensional optimum signal constellation design (OSCD) method, storing coordinates obtained by the D-dimensional OSCD method for a plurality of optical signal to noise ratio (OSNR) values in a look-up-table (LUT); selecting a point from the LUT using encoded data streams; inputting the coordinates into a D-dimensional modulator after digital-to-analog conversion (DAC); and transmitting a modulated signal over a fiber-optic medium of interest.