Patent ID: 9698939
Date: 2017-07-04
CPC Classifications: H04B,H04L

Claim:
1. A method of transmitting a data signal using an optical transmitter of an optical communications system, the method comprising: processing an N-bit input vector in accordance with a first mapping to generate a corresponding M-bit data stream, wherein N≦M; processing the M-bit data stream in accordance with a predetermined Forward Error Correction (FEC) encoding scheme to generate an encoded signal; mapping the encoded signal to symbol values in accordance with a modulation scheme to generate a corresponding symbol stream; and a modulator of the optical transmitter modulating a carrier light in accordance with the symbol stream to generate an optical signal for transmission through the optical communications system, wherein the first mapping comprises a tree code implemented by a plurality of nodes arranged in layers, each node having an input connected to receive a signal from a node in a previous layer and at least two outputs, the nodes of each layer being further configured to receive a respective bit of the N-bit input vector and implement a memoryless logical operation which divides the signal received via its input between each of its outputs based on the value of the received bit of the N-bit input vector.