Abstract: 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.

Abstract: 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<2M, 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.

Abstract: 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.

Abstract: A method for generating a codebook includes applying a unitary rotation to a baseline multidimensional constellation to produce a multidimensional mother constellation, wherein the unitary rotation is selected to optimize a distance function of the multidimensional mother constellation, and applying a set of operations to the multidimensional mother constellation to produce a set of constellation points. The method also includes storing the set of constellation points as the codebook of the plurality of codebooks.

Abstract: 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.

Abstract: 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 signalling interval, and has a second value when averaged across more than one and fewer than 100 signalling 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.