Ciena Corporation

Nortel Networks Corporation

Iena Corporation

Christian Bourget

Michael Y Frankel

Lyndon Y Ong

Loudon Thomas Blair

David W Boertjes

Michael John Wingrove

Alberto Ginesi

Jamie Gaudette

Andrew Deczky

Fred Stacey

Shahab Oveis Gharan

James St Harley

Eric Maniloff

Mark Edward Rollins

Ian Mes

Song Zhang

Marc Veilleux

Ian Dublin

Francois Tremblay

James St Leger Harley

Steven Clarke

Yatish Kumar

Duncan Baird

Mohammad Pakravan

Kendal Zimmer

Hoang-Bao Le Van

Signal-to-noise ratio (SNR)-based bit error ratio (BER) calculations for reporting beyond a forward error correction (FEC) threshold include measuring signal-to-noise ratio (SNR) of a first signal; extrapolating the SNR of a first signal to determine an SNR of a second signal; and determining a pre-FEC bit error rate (BER) for the second signal based on the determined SNR of the second signal. The process can further include reporting the determined pre-FEC BER. The measuring and extrapolating can be used when the second signal is beyond the FEC threshold.

Signal-to-noise ratio-based bit error ratio calculation for reporting beyond a forward error correction threshold

A method performed at a transmitter comprises generating a set of digital signals representing a constellation point, each dimension of the point being uniquely represented by m bits, where m&#x3f5;{1, 2, 3}; applying a linear polyphase filter to a digital signal of the set, the linear polyphase filter pre-compensating for a linear transfer function of an electro-optic path of the digital signal and generating a first filtered signal having a roll-off factor &#x3b1;, where &#x3b1; is a positive real number satisfying &#x3b1;&#x2264;1; applying a nonlinear polyphase filter to the digital signal, in parallel to applying the linear polyphase filter to the digital signal, the nonlinear polyphase filter generating a second filtered signal representing nonlinear noise in the electro-optic path; calculating a pre-compensated digital signal from a difference between the first and second filtered signals; and transmitting an optical signal based on the pre-compensated digital signal.

Low-power pre-compensation of linear and nonlinear transmitter effects in narrow-spectrum optical signals

Systems and methods for path computation in an optical network include obtaining optical layer characteristics related to one or more optical paths in the optical network based in part on performance measurements in the optical network; responsive to service establishment or service restoration, determining a path from source to destination based on utilizing the optical layer characteristics to confirm physical validity of the path; and provisioning a service on the determined path from the source to the destination in the optical network.

Path computation based on dynamic performance monitoring systems and methods in optical networks

The present disclosure provides dynamic performance monitoring systems and methods for optical networks to ascertain optical network health in a flexible and accurate manner. The present invention introduces accurate estimations for optical channel performance characteristics based either on existing channels or with a dynamic optical probe configured to measure characteristics on unequipped wavelengths. Advantageously, the dynamic performance monitoring systems and methods introduce the ability to determine physical layer viability in addition to logical layer viability.

The present disclosure provides a multi-carrier optical transmitter, receiver, transceiver, and associated methods utilizing offset quadrature amplitude modulation thereby achieving significant increases in spectral efficiency, with negligible sensitivity penalties. In an exemplary embodiment, an optical transmitter includes circuitry configured to generate a plurality of optical subcarriers, a plurality of data signals for each of the plurality of subcarriers, and a plurality of modulator circuits for each of the plurality of subcarriers, wherein each of the plurality of modulator circuits includes circuitry configured to offset an in-phase component from a quadrature component of one of the plurality data signals by one-half baud period.

Multi-channel optical transceiver with offset quadrature amplitude modulation

Coherent probe and optical service channel systems and methods for optical networks

Dynamic performance monitoring systems and methods for optical networks

The present disclosure relates to coherent optical receiver systems and methods for determining and correcting for optical angle and magnitude imbalance and for delay imbalance between quadrature paths. The present invention iteratively determines and corrects imbalance error and differential delay entirely in the digital domain (after an analog to digital conversion) in the presence of all the other impairments (polarization mode dispersion, chromatic dispersion, polarization gain imbalance, and polarization delay imbalance) using only the corrupted received signal during normal operation, i.e. without the use of training data. The present invention provides an effective adaptive scheme to drive impairments to zero, without using of any calibration of training, and may be applied during normal operation of the receiver via electrical circuitry or the like.

Coherent optical receiver systems and methods

A system and method for optimizing the transmission of signals over a group of wires. In a preferred form of the present invention, a multi-wire bus connects a common card to a plurality of line cards. A framing protocol controls transmissions between the common card and the plurality of line cards. The framing protocol includes a frame having a prefix that identifies in which direction a given transmission will occur. The prefix also identifies over which wire or wires a given line card will receive data. Each of the line cards are configured to interpret the prefix so that at any given time data can be transmitted from the common card to one or more of the line cards by either transmission over a single wire or a plurality of wires.

Configuring data transmission over one or more line cards globally or individually

A circuit and method is provided for reducing the effect of having potentially different sizes for an Inverse Discrete Fourier Transform (IDFT) at a transmitter and a Discrete Fourier Transform (DFT) at a receiver in a telecommunications system without requiring a change in the DFT's size. The method includes following steps. The first step includes determining whether the IDFT size is greater than, equal to, or less than the DFT size. The second step includes selecting a target impulse response length from a predefined set of impulse response lengths in accordance with a result the previous step. The third step includes training an equalizer at the receiver to the target impulse response length. The circuit comprises hardware and software for implementing the method.

Equalization scheme for DSL receivers in presence of an under-sampled or over-sampled transmit IDFT

A single instruction, multiple data (SIMD) architecture for controlling the processing of plurality of data streams in a digital subscriber line (DSL) system has a memory for storing the data from the channels, a processor operatively coupled with the memory for processing data from the data streams, and a controller for controlling the processor. Storing the data in the memory de-couples the operating rate of the processor and the operating rate of the data streams.

Flexible buffering scheme for multi-rate SIMD processor

A system and method for reducing peak to average power ratio (PAR) in single and multi-carrier transmitters while accounting for the effect of the transmit filters without significantly affecting a requisite transmission Power Spectral Density (PSD) mask. To this end, in a multicarrier communication system, a DSL transmitter is provided that transmits a multicarrier symbol having a controlled peak-to-average power ratio (PAR) and which is a function of a plurality of information signals. The transmitter has a power reducer that reduces the PAR of the multicarrier symbol by modifying a selected information signal of a plurality of information signals, the modified signal including an information component, a peak reduction component, and a transmission channel response component.

Peak to average power ratio reduction in communication systems

A discrete multitone (DMT) receiver has a time domain equalizer (TDEQ) which is trained during initialization using an estimated channel impulse response (CIR). To eliminate wrap-around of the estimated CIR relative to the DMT frame alignment, and to remove leading zeroes, the estimated CIR is circularly advanced relative to the frame alignment for training the TDEQ. In subsequent communications of DMT symbols via the channel and the TDEQ, the equalized samples of the received DMT symbols are buffered to compensate, in a frame alignment of the received DMT symbols, for the advance of the estimated CIR in the initialization process and for a delay in the TDEQ.

Frame alignment and time domain equalization for communications systems using multicarrier modulation

A time domain equalizer for a discrete multi-tone modem that includes an estimation of the contribution of out of band noise and echo to the overall channel impulse response. At start up the modem estimates out of band noise and echo. Using a minimum mean square error analysis, the time domain equalizer taps can be determined, taking into account the estimated out of band contribution. As a result, less complex duplexing filters, and time domain equalizer, are required.

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Stittsville, Canada

Christian Bourget