Patent Document ID: 9621275
Application ID: 14320766
Patent Flag: 1

Claim One:
1. A computer-implemented method for generating a code for modulating signals transmitted for coherent optical communications, using a processor in connection with a memory, comprising: providing codewords represented by points in a constellation of the code into the memory; projecting the points in the constellation of the code onto a hyper-sphere by normalizing a sum of power over multiple dimensions to produce a multi-dimensional constellation, wherein the code is L-dimensional N-ary amplitude M-ary phase-shift keying including 4D-2A8PSK and 4D-2AQPSK, wherein amplitudes and phase offsets of the code are optimized, and wherein a sum of powers over L dimensions is constant for all codewords in the code; identifying point pairs having a smallest distance in the multi-dimensional constellation that limits a performance of the code; adjusting the point pairs in the multi-dimensional constellation to improve the performance of the code; and iterating the identifying and the adjusting until convergence, wherein the steps are performed in the processor.