Data synchronization in optical networks and devices
AssigneeInfinera Corporation
InventorsMehdi Torbatian, Yuliang Gao, Ahmed Morra, Han Henry Sun, Yeongho Park
Life of this patent
Estimating the term…
Abstract
Joint estimation of the framer index and the frequency offset in an optical communication system are described among various other features. A transmitter can transmit data frames using pilot and framer symbols. A receiver can estimate the framer index and frequency offset using the pilot and framer symbols, and identify the beginning of a header portion of a data frame. By identifying the beginning of the header portion of a data frame, the receiver can then process data received from the transmitter in a manner synchronous to the manner in which the data was transmitted by the transmitter.
Claims20
An apparatus comprising:
- a receiver circuit operable to receive a modulated optical signal carrying data indicative of a frame of symbols, the frame of symbols including a frame header and a payload, the frame header having header symbols and the payload having payload symbols, the receiver circuit being operable to provide an electrical signal based on the modulated optical signal;
- and
- a processor circuitry operable to:
- obtain the frame of symbols from the receiver circuit based on the electrical signal;
- obtain data indicative of an upsampling factor associated with the receiver circuit;
- and
- determine a framer index and a starting location of the frame header within the electrical signal based on the frame of symbols and the upsampling factor.
A receiver operable to communicate with a transmitting device over an optical network, the receiver comprising:
- an optics circuit configured to receive a signal comprising subcarrier signals, each of the subcarrier signals comprising data indicative of a data frame that comprises (i) a frame header comprising framer symbols and a first set of pilot symbols, and (ii) a payload comprising payload symbols and a second set of pilot symbols;
- and
- a digital signal processor operable to:
- configure a sliding window according to an upsampling factor associated with the optics circuit;
- determine, for each frame header, a starting location of the frame header within the received signal using the sliding window configured according to the upsampling factor associated with the optics circuit;
- and
- synchronize data transmission between the receiver and the transmitting device based on the starting location of the frame header.
An apparatus comprising:
- a polarization beam splitter operable to receive a signal comprising a plurality of subcarrier signals from a fiber optic cable, each of the subcarrier signals comprising data indicative of a data frame that comprises (i) a frame header comprising framer symbols and a first set of pilot symbols, and (ii) a payload comprising payload symbols and a second set of pilot symbols, wherein the polarization beam splitter is operable to separate the received signal into at least two polarization components;
- a laser operable to output a light signal;
- a first mixer operable to receive the light signal and a first component of the two polarization components, and to generate a first signal component;
- a second mixer operable to receive the light signal and a second component of the two polarization components, and to generate a second signal component;
- analog to digital conversion circuitry operable to receive and digitize the first signal component and the second signal component;
- and
- at least one processor operable to:
- obtain the first signal component and the second signal component from the analog to digital conversion circuitry;
- configure a sliding window according to an upsampling factor indicative of a ratio between a sampling rate of the apparatus to a symbol rate associated with the data frame;
- and
- determine, for each frame header, a starting location of the frame header within the received signal using the sliding window configured according to the upsampling factor and the first signal component and the second signal component.
Dependencies are inferred from the claim text.