US 7,600,171 B2 · Method of controlling FEC in EPON

Abstract

A method of controlling a Forward Error Correction (FEC) operation including: configuring a FEC frame to be transmitted between an OLT and an ONU comprising a FEC frame identifier indicating whether FEC should be performed, data, a first flag indicating that FEC should be performed, and a second flag indicating that the FEC frame is to be FEC encoded; initializing the OLT by disabling a FEC function; determining whether the ONU requires FEC to be performed based on a FEC frame identifier received from the ONU; IPG stretching the FEC frame when the ONU requires to FEC to be performed; and transmitting the FEC frame to the ONU after FEC encoding based on the second flag of an input frame to a PCS sublayer from an upper layer. The method controls an effective operation of a FEC of an ONU and an OLT without changing a Round Trip Time (RTT) according to optical link quality in an EPON. Accordingly, FEC is used only if necessary, thereby simplifying the managing of a link, and preventing an excessive 35% reduction of throughput caused by use of unnecessary FEC.

Claims9

Dependent claims

A method of controlling a Forward Error Correction (FEC) operation of an OLT, comprising:

configuring a FEC frame to be transmitted between an OLT and an ONU, said FEC frame comprising data, a first flag indicating that FEC encoding is to be provided, and a second flag requiring the OLT and the ONU to encode the FEC frame;
determining, at the ONU, whether FEC encoding is required based on a FEC frame identifier received from the OLT;
performing IPG stretching at the ONU when FEC encoding is required;
and
transmitting the FEC frame to the ONU after FEC encoding based on the second flag of the FEC frame to a physical coding sublayer from an upper layer.

2 more elements

A method of controlling a Forward Error Correction (FEC) operation of an OLT with respect to transmitting between the OLT and an ONU a FEC frame comprising data, a first flag indicating that FEC encoding is to be provided, and a second flag requiring the OLT and the ONU to encode the FEC frame, a third flag indicating that the FEC frame is an IPG stretched frame, the method comprising:

when the ONU does not perform FEC encoding, the ONU disabling the first and the second flags and proceeding discovery with the OLT;
when the ONU does perform FEC encoding, the ONU disabling a data path to a physical coding sublayer, and determining whether to perform an error monitoring according to a state of a first flag of a frame received from the OLT, said state being one of enabled and disabled;
when the first flag of the frame received from the OLT is disabled, enabling, at the ONU, the first flag of the frame transmitted to the OLT, enabling the data path;
when the first flag of the frame received from the OLT is enabled, performing error monitoring at the ONU;
and
when the error monitoring is performed, determining, at the ONU, whether to use FEC encoding based on a Bit Error Rate (BER), enabling the data path, and allowing the discovery.

3 more elements

Dependencies are inferred from the claim text.

Method of controlling FEC in EPON

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Method of controlling FEC in EPON

Life of this patent

Abstract

Claims9