Ciena Corporation

Apple Inc.

Mahmoud Taherzadehboroujeni

Kim Bryon Roberts

Shahab Oveis Gharan

Amir Keyvan Khandani

Jianglei Ma

Wen Tong

Peiying Zhu

Ming Jia

Dong-Sheng Yu

Hosein Nikopour

Akbar Ghasemi

William Martin Snelgrove

Maurice M O'Sullivan

Hosein Nikopourdeilami

Michael Andrew Reimer

Andrew D Shiner

Bertram Leesti

Methods and devices are provided for MIMO OFDM transmitter and receivers having odd and/even numbers of transmit antennas. Various methods for pre-coding information bits before space time coding (STC) are described for enabling transmission of information bits over all antennas. Methods of decoding received signals that have been pre-coded and STC coded are also provided by embodiments of the invention. Pilot patterns for downlink and uplink transmission between a base station and one or more wireless terminals for three transmit antenna transmitters are also provided. Variable rate codes are provided that combine various fixed rate codes in a manner that results in codes whose rates are dependent on all the various fixed rate codes that are combined.

System and method for mapping symbols for MIMO transmission

A transmitter of a communications system includes a first encoder configured to apply a shaping operation to a data signal to generate a shaped data signal, a second encoder configured to encode the shaped data signal according to a forward error correction (FEC) scheme to generate an encoded signal, and a constellation mapper configured to modulate the encoded signal to symbol values according to a modulation scheme to generate a corresponding symbol stream for transmission through the communications system. The shaping operation reduces average constellation energy for constellations of the modulation scheme.

Variable spectral efficiency optical modulation schemes

A method of data symbol recovery in a coherent receiver of an optical communications system includes processing data symbol estimates detected from a received optical signal, and determining recovered symbol values from the processed data symbol estimates. The recovered symbol values belong to a symbol constellation having a predetermined asymmetry. Processing the data symbol estimates compensates phase noise that is greater than one decision region of the symbol constellation. A coherent receiver of an optical communications system includes a module configured to process data symbol estimates detected from a received optical signal and a decision circuit configured to determine recovered symbol values from the processed data symbol estimates. The recovered symbol values belong to a symbol constellation having a predetermined asymmetry. Processing the data symbol estimates compensates phase noise that is greater than one decision region of the symbol constellation.

Minimum variance carrier recovery with increased phase noise tolerance

A method of transmitting a data signal using an optical transmitter of an optical communications system. A first encoder processes an N-bit input vector in accordance with a first mapping to generate a corresponding M-bit data stream. A Forward Error Correction encoder processes the M-bit data stream in accordance with a predetermined FEC encoding scheme to generate an encoded signal. A constellation mapper maps the encoded signal to symbol values in accordance with a predetermined modulation scheme to generate a corresponding symbol stream. A modulator modulates a carrier light in accordance with the encoded symbol stream to generate an optical signal for transmission through the optical communications system. The first mapping can be adjusted to maximize performance of the optical communications system.

A receiver of an optical communications system includes a set of two or more analog-to digital A/D converters, a respective transform block connected to an output of each A/D converter, and a summation block. Each A/D converter samples a respective low-bandwidth analog signal comprising a respective portion of a high-bandwidth data signal. Each transform block calculates a set of spectral components of the respective low-bandwidth analog signal. The summation block combines respective spectral components calculated by each transform block to construct spectral terms of a combined signal having a spectrum corresponding to that of the high-bandwidth data signal.

Frequency domain combination of parallel signal paths

In a coherent receiver of an optical communication system, a method of processing a detected symbol estimate to determine a most likely value of a corresponding transmitted data word, the transmitted data word comprising one or more data bits encoded in a transmitter using a predetermined constellation of at least two symbols. A set of two or more virtual constellation points are define in a decision region corresponding to a possible value of the data word. The detected symbol estimate is processed to find a most likely virtual constellation point given the detected symbol estimate. The most likely value of the corresponding transmitted data word is determined based on the most likely virtual constellation point.

Maximum likelihood decoding

A method of data symbol recovery. An optical signal is modulated by a transmitter using a modulation scheme comprising a symbol constellation having a predetermined asymmetry and detected at a receiver. Phase error estimates corresponding to data symbol estimates detected from the received optical signal are calculated. A phase rotation is calculated based on the phase error estimates, using a filter function, and the phase rotation applied to at least one data symbol estimate to generate a corresponding rotated symbol estimate. The phase error estimates model the asymmetry of the symbol constellation, such that the computed phase rotation can compensate phase noise that is greater than one decision region of the symbol constellation.

A method of transmitting a data signal using an optical transmitter of an optical communications system. The optical transmitter is configured to modulate an optical carrier in successive signalling intervals to generate an optical signal. A modulation scheme is provided which comprises a multi-dimensional symbol constellation. The modulation scheme is designed such that an average degree of polarization of a modulated optical signal output from the optical transmitter has a first value when averaged across a first signaling interval, and has a second value when averaged across more than one and fewer than 100 signaling intervals. The second value is less than 10 percent of the first value. During run-time, an encoder of the optical transmitter encoding a data signal to be transmitted as symbols of the constellation, and a modulator of the optical transmitter modulating available dimensions of the optical carrier in accordance with the symbols.

Optical modulation schemes having reduced nonlinear optical transmission impairments

A method of transmitting data. The method comprises preliminarily providing a modulation scheme comprising an N-symbol constellation defined in an M-dimensional space, wherein N&#x3c;2, and a composite distance between a given pair of symbols within the constellation increases with increasing Hamming distance between data words encoded in each of those symbols. During run-time, a data signal to be transmitted is encoded as symbols of the constellation, and modulated onto at least M dimensions of a carrier light in accordance with the symbols.

Noise-tolerant optical modulation

A frequency decimation block for processing an analog input signal including a high-bandwidth data signal to generate a parallel set of parallel output signals, in which each output signal represents a respective portion of the high-bandwidth data signal. A preamplifier is provided for amplifying the input signal. A frequency domain divider divides the amplified input signal to generate a set of frequency band signals including a low frequency band signal, a mid-frequency band signal, and a high frequency band signal. Each frequency band signal is supplied to at least one signal path. A respective non-linear processor is connected in each of M signal paths processes the input signal using a respective branch signal to yield a corresponding composite signal. A respective Low-Pass Filter (LPF) is connected in each signal path, for low-pass filtering at least the composite signals to generate corresponding ones of the parallel output signals.

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Ottawa, Canada

Mahmoud Taherzadehboroujeni