Abstract: An optical transmission system includes a plurality of optical nodes that transmits wavelength multiplexing light including a plurality of signal light components having different wavelengths, wherein each of the optical nodes includes superimposed signal light generation circuit which superimposes a low frequency signal having a common frequency on a corresponding signal light component included in the wavelength multiplexing light; low frequency signal extraction circuit which extracts a low frequency signal having a frequency of a given range from a corresponding signal light component; and pass-through node number measurement circuit which measures, for each of the signal light components, a pass-through node number based on the frequency of the low frequency signal extracted by the low frequency signal extraction circuit, the pass-through node number being the number of optical nodes through which the signal light component has passed before being transmitted to a specific optical node.

Abstract: In an optical transmission apparatus, a light-emitting laser varies its output wavelength when applied with a wavelength control signal for switching wavelengths. A wavelength controller outputs the wavelength control signal, and a filter unit subjects the wavelength control signal to a filtering process to remove high-frequency noise superimposed on the wavelength control signal. The filter unit stops the filtering process during the wavelength control and executes the filtering process during the operation.

Abstract: A method for multi-level data transmission includes encoding a data signal to be transmitted into N multi-level signals in accordance with an encoding table, where the data signal is characterized with a stream of binary data segments each of which has a data length of M bits, transmitting simultaneously the N multi-level signals through N data transmission channels, respectively; and decoding the N multi-level signals into the data signal by comparing each two of the N multi-level signals transmitted through the two data transmission channels to obtain a respective bit of the M bits of each binary data segment of the data signal based on comparison between the two corresponding multi-level signals.

Abstract: The present invention provides an aperiodic channel quality information sending method and a mobile terminal. The method comprises: a mobile terminal and network side pre-appointing one or more transmission modes which support the forming of dual flow beam, and aperiodic channel quality information CQI feedback mode(s) corresponding to the transmission modes; the network side indicating the mobile terminal with one pre-appointed transmission mode to be adopted, wherein when the mobile terminal receiving the indication of adopting the one pre-appointed transmission mode, the mobile terminal adopts the aperiodic CQI feedback mode corresponding to the one pre-appointed transmission mode to feed back the CQI information to the network side. The method of the present invention facilitates the reduction of signaling overhead and feedback overhead, the increase of the feedback dimensionality of the channel information, and the improvement of the throughput of the system.

Abstract: Methods for compensation of imbalance between I (In-phase) and Q (Quadrature) signal paths (12a, 12b, 605a, 605b) in a quadrature receiver (8) and a quadrature transmitter (600) are disclosed. In the receiver case, the imbalance is compensated for by means of post-distortion in the digital domain. In the transmitter case, the imbalance is compensated for by means of pre-distortion in the digital domain. The methods can be carried out with a relatively low computational complexity. Signal-processing devices (30, 610) for carrying out the methods are disclosed as well. The same basic internal structure may be used for the signal-processing device (30) in the receiver case as for the signal processing device (610) in the transmitter case.

Abstract: The present invention discloses an OFDM signal demodulation method and device thereof.

Abstract: In a particular embodiment, a method of providing redundancy for error recovery in multi-carrier wireless communications includes transmitting a primary version of information via a first carrier, transmitting a first portion of a redundancy version of the information via a second carrier, and transmitting a second portion of the redundancy version of the information via a third carrier. The primary version is encoded using a first encoding scheme and the redundancy version is encoded using a second encoding scheme. The primary version, the first portion, and the second portion are transmitted substantially simultaneously.

Abstract: Embodiments of an OFDM transmitter and method of reducing the effects of interference on subcarriers in an OFDM system by symbol loading are disclosed herein. A linear transformation is performed on a group of two or more input data symbols to generate a corresponding two or more output data symbols. Each of the output data symbols has an increased number of constellation points and are configured for transmission within one of the different signal dimensions using two or more antennas. Each of the two or more output data symbols carry the information of each of the input data symbols of the group. This coding together of input data symbols that are mapped to different signal dimensions may provide improved reliability against fading and severe interference. The different signal dimensions may comprise a frequency, a time and/or a space dimension.

Abstract: The frequency of a digital data signal, such as a digital video signal, is intentionally varied or hopped before being sent over a network. This frequency hopping may be performed in accordance with a frequency hopping pattern shared with only intended receivers. The digital data signal may be further intentionally pre-distorted in accordance with a pre-distortion pattern which is also shared with only intended receivers. The frequency hopping and/or the pre-distortion patterns may be used to vary the frequency and modulation, respectively, on a periodic basis, such as a symbol-by-symbol or packet-by-packet basis.

Abstract: Methods are described for near optimal Antenna and/or sensor selection via population-based probabilistic evolutionary algorithms such as estimation of distribution algorithm (EDA) and bio-inspired Optimization (BIO). The aspects of the invention includes a method for joint transmit and receive antenna selection using EDA; and an enhanced EDA, which uses cyclic shift register and biased estimation of distribution; and methods for joint transmit and receive antenna selection using improved population-based optimization. The proposed EDA-based and bio-inspired selection methods results in performances that are close to the ESA (exhaustive search algorithm) and yet impose mush less computational burden than ESA. Another advantage of our methods is that they can be easily implemented on parallel processors.

Abstract: An OFDM modulation/demodulation method in a transmission system that transmits data from a transmission source to a transmitting destination through OFDM modulation/demodulation is provided, which includes an extension step of extending, by the transmission source, a symbol period by copying an OFDM-modulated symbol in a predetermined place of the OFDM-modulated symbol for a predetermined length; a transmission step of transmitting, by the transmission source, the OFDM-modulated symbol that includes the extended symbol period to the transmitting destination; a demodulation performance step of receiving, by the transmitting destination, the OFDM-modulated symbol from the transmission source and performing OFDM demodulation of the received OFDM-modulated symbol from a plurality of time points; and a selection step of selecting, by the transmitting destination, the demodulation result of the OFDM demodulation to be adopted on the basis of the demodulation results of the OFDM demodulation from the plurality of ti

Abstract: A method for processing user symbols with Tomlinson Harashima precoder (THP) in a base station, of a wireless system having K user terminals (UEs) which communicate with the base station via an uplink channel and corresponding downlink (DL) channel, comprises estimating a DL channel matrix Hk; determining receiver processing matrix Vk; computing an effective matrix DL channel Heff; performing QR decomposition of Heff; computing THP matrices; calculating scalar weights for the UEs; processing user symbols by the THP having the THP matrices to produce an output of filtered vector symbols for the UEs; directing output of the THP to the channel represented by the DL channel matrix through which communications occur in the wireless system with the UEs; performing additional receiver processing on the transmitted signals at the UEs based on Vk for each of the K UEs; and using the scalar weights on the transmitted signals at the UEs.

Abstract: There is provided a method of interactive compression using multiple compression state information entries. The method comprises receiving a request for data from a communicating party; retrieving the data; identifying, for use in compressing the data, at least two compression state information entries shared between the parties to the communication; compressing the data with each of the at least two compression state information entries; determining, from the set of compression state information entries, a preferred compression state information entry that provides a greatest compression ratio; and transmitting the data, compressed in accordance with the preferred compression state information entry to the communicating party.

Abstract: A transmitter is for use with multiple transmit antennas and includes a precoder unit configured to precode data for a transmission using a precoding matrix selected from a codebook, wherein the codebook corresponds to the following three transmission properties for an uplink transmission: 1) all precoding elements from the precoding matrix have a same magnitude, 2) each precoding element from the precoding matrix is taken from a set of finite values and 3) there is only one non-zero element in any row of the precoding matrix. The transmitter also includes a transmit unit configured to transmit the precoded data.

Abstract: A method for adaptively learning a sparse impulse response (100) of a continuous channel to which an input signal (x(t)) is applied and which delivers an output signal (y(t)), comprising the following steps: low-pass filtering the input signal and the output signal and obtain a filtered input signal (xF(t)) and a filtered output signal (yF(t)) sampling the filtered input signal and the filtered output signal with a sampling rate below the Nyquist rate and obtaining a sampled input signal (xS(t)) and a sampled output signal (yS(t)) retrieving from the sampled input signal (xS(t)) and the sampled output signal (yS(t)) an estimate (400) of the sparse impulse response (100) of the continuous channel.

Abstract: A method, apparatus and system are disclosed herein for channel classification and adaptation.

Abstract: A headend transmitter that transmits 1024 QAM including a 256 QAM modulator which has been modified to have more aggressive forward error correction processing. The 256 QAM modulator outputs 256 QAM points to a summer. Another data modulator receives additional data to be transmitted in a separate, substantially less complex constellation. This modulator processes the additional data to do forward error correction thereon and then maps the encoded data into a less complex constellation such as QPSK, 16 QAM etc. The additional data constellation points are then amplified in a variable gain amplifier and fed to a summer where each additional data point is added by vector summation to one 256 QAM point. The output 1024 QAM point is filtered and shifted to the desired transmission frequency. Legacy cable modem receivers can still receive the 256 QAM point since the addition of the new data just appears to be noise which they can overcome using the parity bits encoded in the transmitted symbols.

Abstract: The invention relates to information transmission methods, in particular to the communication interfaces of electronic devices. The inventive method makes it possible to increase the communication range and reliability by improving noise protection through the compensation of a noise signal during the transmission and reading of the signal in both wires of a communication line. The inventive method involves connecting the first pole of a voltage supply source to the first wire of a two-wire transmission line via a first resistor and connecting the second pole of said voltage supply source to the second wire of the two-wire transmission line via a second resistor. Moreover, the first and second resistors have the equal resistance values, and a receiver is connected to the two-wire transmission line between a transmitter and the voltage supply source and is provided with two current sensors. A reading signal is defined as the sum of absolute values of the measured currents.

Abstract: A method and apparatus for reducing the amplification of the duty cycle distortion of high frequency clock signals when is provided. A data signal is sent to a receiver via a first channel. A clock signal is sent to the receiver via a second channel. The clock signal is filtered to substantially remove therefrom low frequency components before the clock signal is used by the receiver to recover data from the data signal.

Abstract: A carrier frequency offset (CFO) estimation and synchronization method and apparatus of an orthogonal frequency division multiplexing (OFDM) receiver receiving an OFDM modulated signal. The OFDM receiver's CFO synchronization method includes step (a) performing an initial CFO estimation pull-in step using double correlation, step (b) performing a coarse residue CFO estimate acquisition step using independent combination of the double correlation and auto-correlation, and step (c) performing a small residue CFO tracking step by using the double correlation. Aspects of the invention solves the problems in the related art that a CFO tracking range cannot be reliably used in practice when the CFO tracking range is too narrow and a CFO estimation error increases when the CFO tracking range is too wide.