Line coding for optical transmission
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorsFabio Cavaliere, Enrico Forestieri
Life of this patent
Estimating the term…
Abstract
Digital data (11) is encoded to a set of five line symbols for optical transmission. The line symbols have amplitude values of 0, ±A1, ±A2, where |A2|>|A1|. A first binary value maps to the line symbols 0 and ±A2 and a second binary value maps to the line symbols ±A1. The amplitude values of the line symbols can be in the ratio A1:A2=1:sqrt(2). At a receiver, the received signal is photodetected to generate an electrical signal which can represent a set of three possible received symbols (RS1, RS2, RS3). Digital data (26) is recovered from the received symbols by comparing the electrical signal with a first amplitude threshold (TH1) and a second amplitude threshold (TH2).
Claims21
A method of line coding for optical transmission comprising:
- encoding digital data to a set of five line symbols;
- where the line symbols have amplitude values of 0, ±A1, ±A2, where |A2|>|A1|, where:
- a first binary value maps to the line symbols 0 and ±A2;
- a second binary value maps to the line symbols ±A1.
A method of receiving an optical signal in which digital data has been encoded to a set of five line symbols, where the line symbols have amplitude values of 0, ±A1, ±A2, where |A2|>|A1|, where a first binary value maps to line symbols 0 and ±A2 and a second binary value maps to line symbols ±A1, the method comprising:
- photodetecting the received signal to generate an electrical signal which can represent a set of three possible received symbols;
- recovering the digital data from the received symbols.
A line encoding apparatus for encoding a signal for optical transmission, the line encoding apparatus comprising processing circuitry, the processing circuit being configured to cause the line encoding apparatus to configured to:
- encode digital data to five line symbols;
- where the line symbols have amplitude values of 0, ±A1, ±A2, where |A2|>|A1|, wherein the apparatus is configured to map:
- a first binary value to the line symbols 0 and ±A2;
- a second binary value to the line symbols ±A1.
An optical receiver comprising:
- a photodetection stage which is configured to receive an optical signal and to output an electrical signal, wherein the optical signal carries digital data which has been encoded to a set of five line symbols, where the line symbols have amplitude values of zero, ±A1, ±A2, where |A2|>|A1|, where a first binary value is mapped to line symbols 0 and ±A2 and a second binary value is mapped to line symbols ±A1, and where the electrical signal can represent a set of three possible received symbols;
- a digital data recovery stage which is configured to recover the digital data from the received symbols.
Dependencies are inferred from the claim text.