Communication apparatus, transmitter, receiver, and error correction optical communication system

Abstract

A communication apparatus includes a transmitter and a receiver, wherein the transmitter further includes: an interleaver that rearranges positions of bits of an information frame; an FEC encoder that performs an error correction encoding to the information frame whose bit positions have been rearranged; and a selector that inserts FEC parity into predetermined positions of the information frame, to thereby generate a transmission signal, whereas the receiver includes: a selector that extracts an information frame part and an FEC parity part from a reception signal; an interleaver that rearranges positions of the bits of the information frame part using the same rule as that used at that transmitter side; an FEC decoder that corrects an error of bits rearranged based on the error correction parity part; and a de-interleaver that reproduces an information frame by returning positions of error-corrected bits to original bit positions.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to an error correction optical communication system having a forward error correction (FEC) function, and, more particularly to an error correction optical communication system that transmits and receives a non-interleaved information frame. [0003] 2. Description of the Related Art [0004] An optical access system, a so-called “Fiber To The Home (FTTH)”, that transmits large-capacity information to houses and offices, is being distributed rapidly. Among others, the service of “Gigabit Ethernet (registered trademark, and hereinafter referred to as “Ethernet®”) PON (normally known as GE-PON)” that uses a “Passive Optical Network (PON)” system is being spread rapidly as a method of connecting Gigabit Ethernet® between a telecommunications house and plural users, since specifications are standardized in the IEEE Std 802.3ah. [0005] The GE-PON has a configuration that an “Optical Line Termina...

AI Technical Summary

Benefits of technology

[0002] The present invention relates to an error correction optical communication system having a forward error correction (FEC) function, and, more particularly to an error correction optical communication system that transmits and receives a non-interleaved information frame.

Problems solved by technology

Consequently, a bit error is likely to occur.

Furthermore, the fact that a laser diode having low performance is being used to decrease the cost is also likely to cause this bit error problem.

However, when a bit error occurs extending to nine bytes, the Reed-Solomon (255, 239) cannot correct the error.

In a transmission path of actual optical communications, bit errors occur continuously in some cases, due to a fluctuation of polarization, non-linearity of an optical fiber, or insufficient performance of a transmitter / receiver.

Even when the total number of bit errors that occur during a predetermined time is equal to or smaller than the number of bit errors that the Reed-Solomon (255, 239) error correction system can correct, the errors cannot be corrected when these bit errors are burst errors which occur during a short period of time.

This is because when the interleave of the Ethernet® data series is carried out, a system that does not have a de-interleaver (not using the FEC) at the reception side cannot receive the data.

In other words, the burst error tolerance is considerably low.

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