Systems for improved spectral efficiency in multi-carrier communication systems
First Claim
1. An optical transceiver comprising:
- an optical transmitter coupled to an optical link, including;
a transmitter-side optical comb generator configured to generate a plurality of transmitter-side carrier signals, the plurality of transmitter-side carrier signals being equally spaced in frequency, wherein;
a frequency spacing between any two adjacent transmitter-side carrier signals is less than a baud rate of data modulated on each of a plurality of transmitter-side modulated carrier signals, andthe transmitter-side optical comb generator generates the plurality of transmitter-side carrier signals using a first pilot carrier signal received from a remote transceiver to which the plurality of transmitter-side modulated carrier signals are transmitted,a modulator configured to modulate data onto each of a first subset of the plurality of transmitter-side carrier signals generated using the first pilot carrier signal to generate the plurality of transmitter-side modulated carrier signals,wherein the transmitter is configured to transmit the plurality of transmitter-side modulated carrier signals and a second subset of the plurality of transmitter-side carrier signals over the optical link, wherein the second subset is disjoint from the first subset;
an optical receiver coupled to the optical link configured to receive a second pilot carrier signal and a plurality of received modulated carrier signals including;
a receiver-side optical comb generator configured to utilize the second pilot carrier signal to generate a plurality of receiver-side carrier signals,wherein the plurality of receiver-side carrier signals are equally spaced in frequency,andeach of the plurality of receiver-side carrier signals has the same frequency as one of the plurality of received modulated carrier signals,a plurality of optical mixers, each optical mixer configured to mix one of the plurality of receiver-side carrier signals with a corresponding one of the plurality of received modulated carrier signals to generate a set of output signals, anda demodulator configured to demodulate the set of output signals based on the respective amplitudes and phases of the output signals to generate output data.
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Accused Products
Abstract
This disclosure provides systems, methods, and apparatus for improving spectral efficiency of a communication system. The communication system can include a transmitter, a receiver and a communication link for communicating data between the transmitter and the receiver. The transmitter can employ a multi-carrier technique to transmit data to the receiver. The transmitter can generate a plurality of carrier signals using a receiver-side comb generator, one of which is sent to the transmitter as a pilot carrier signal combined with modulated carrier signals over an optical link. At the receiver the receiver-side comb generator uses the pilot carrier signal to generate a plurality of receiver-side carrier signals, which are used for detecting the modulated carrier signals. As the phase noise in the modulated carrier signals and the phase noise in the receiver-side carrier signals have the same characteristics, the phase noise is cancelled at the receiver, resulting in improved detection.
41 Citations
13 Claims
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1. An optical transceiver comprising:
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an optical transmitter coupled to an optical link, including; a transmitter-side optical comb generator configured to generate a plurality of transmitter-side carrier signals, the plurality of transmitter-side carrier signals being equally spaced in frequency, wherein; a frequency spacing between any two adjacent transmitter-side carrier signals is less than a baud rate of data modulated on each of a plurality of transmitter-side modulated carrier signals, and the transmitter-side optical comb generator generates the plurality of transmitter-side carrier signals using a first pilot carrier signal received from a remote transceiver to which the plurality of transmitter-side modulated carrier signals are transmitted, a modulator configured to modulate data onto each of a first subset of the plurality of transmitter-side carrier signals generated using the first pilot carrier signal to generate the plurality of transmitter-side modulated carrier signals, wherein the transmitter is configured to transmit the plurality of transmitter-side modulated carrier signals and a second subset of the plurality of transmitter-side carrier signals over the optical link, wherein the second subset is disjoint from the first subset; an optical receiver coupled to the optical link configured to receive a second pilot carrier signal and a plurality of received modulated carrier signals including; a receiver-side optical comb generator configured to utilize the second pilot carrier signal to generate a plurality of receiver-side carrier signals, wherein the plurality of receiver-side carrier signals are equally spaced in frequency, and each of the plurality of receiver-side carrier signals has the same frequency as one of the plurality of received modulated carrier signals, a plurality of optical mixers, each optical mixer configured to mix one of the plurality of receiver-side carrier signals with a corresponding one of the plurality of received modulated carrier signals to generate a set of output signals, and a demodulator configured to demodulate the set of output signals based on the respective amplitudes and phases of the output signals to generate output data. - View Dependent Claims (2, 3, 4)
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5. An optical receiver coupled to an optical link and receiving a plurality of modulated carrier signals and a pilot carrier signal over the optical link, comprising:
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a receiver-side optical comb generator configured to utilize the pilot carrier signal to generate a plurality of receiver-side carrier signals, each receiver-side carrier signal having the same frequencies as respective modulated received modulated carrier signal, wherein a frequency spacing between any two adjacent receiver-side carrier signals is less than a baud rate of data modulated on each of the plurality of modulated carrier signals; a plurality of optical mixers, each optical mixer configured to mix one of the plurality of receiver-side carrier signals with a corresponding one of the plurality of modulated carrier signals to generate a set of output signals; a demodulator configured to demodulate the set of output signals based on the respective amplitudes and phases of the output signals to generate output data and a transmitter for transmitting one of the receiver side carrier signals as a second pilot carrier signal to a remote transmitter that transmits the modulated carrier signals. - View Dependent Claims (6, 7, 8)
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9. A method for communicating optical signals, comprising:
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receiving a plurality of modulated carrier signals over an optical link; receiving an unmodulated carrier signal over the optical link; generating a plurality of receiver-side carrier signals using an optical comb generator, which in turn uses the unmodulated carrier signal as a seed signal, wherein; a frequency spacing between any two adjacent receiver-side carrier signals is less than a baud rate of data modulated on each of the plurality of modulated carrier signals; demodulating the plurality of modulated carrier signals using the plurality of receiver-side carrier signals based on the respective amplitudes and phases of the respective modulated carrier signal; and optically communicating one of the generated receiver-side carrier signals to a remote transmitter from which the modulated carrier signal was received for use by the remote transmitter as a seed signal for a transmitter-side comb generator. - View Dependent Claims (10, 11, 12, 13)
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Specification