Abstract: A coexistence controller which performs management and control of time division for coexistence, is provided in a power line communication modem which has a function as a QoS controller for a QoS type communication system and a power line communication modem for a best-effort type communication system. In the QoS type communication system, by controlling allocation of a communication band in accordance with priorities given to the communication systems by cooperation of the coexistence controller and the QoS controller, the power line communication systems having different schemes can coexist.

Abstract: A frequency band is divided into N subchannels. Sub-channels are first allocated for a power line communication system having a higher priority, such as public communication or the like. Sub-channels for a power line communication system having a relatively low priority, such as in-home communication or the like, are allocated from free subchannels. In this case, the subchannels used by the power line communication system having the high priority are limited to a plurality of consecutive subchannels from an upper side or a lower side of the frequency band.

Abstract: A power line communication apparatus is provided with an auto gain detector that detects a gain fluctuation of an AGC (Auto Gain Control) circuit that automatically adjusts a gain of a received signal; a retry ratio calculator that calculates a ratio of retry based on output from an ARQ (Automatic Repeat request) unit that detects an error in the received data and issues a repeat request; and a transmission rate calculator that calculates a transmission rate based on output from a channel estimation unit that calculates a CNR so as to estimate a transmission status. A display displays a transmission status, including the detected AGC noise fluctuation, retry ratio, transmission rate and the like.

Abstract: The present invention is provided to improve transmission efficiency by preventing interference between different networks during data transmission using a multicarrier communication method. A transmitter includes a phase vector setting unit and a multicarrier modulator. The phase vector setting unit rotates a phase of transmission data corresponding to each subcarrier signal in an OFDM multicarrier signal, by generating a randomized phase vector for each subcarrier signal. The multicarrier modulator modulates the multicarrier signal as transmission data by using an inverse Fourier transform or an inverse wavelet transform. The phase vector setting unit changes a phase vector according to the status of a transmission line or the status of another network.

Abstract: A relay apparatus includes a plurality of connecting terminals, such as a modem connecting terminal, a power line connecting terminal, an electric appliance connecting terminal and an antenna line connecting terminal; a selector that selects at least one connecting terminal from among the plurality of connecting terminals to transmit and receive a communication signal; and a control circuit that controls the selector. The relay apparatus further includes a first communication filter that passes signals in a frequency band used for communication by a power line communication modem and that blocks signals in other frequency bands, and a second communication filter that passes signals in a frequency band used for communication by another electric appliance and that blocks signals in other frequency bands.

Abstract: The invention provides a power-line carrier communication apparatus including a transmission unit with a signal point mapping device for mapping a plurality of bit streams produced from transmission data, a wavelet inverse transforming device for modulating the respective sub-carriers by wavelet waveforms which are orthogonal to each other for producing temporal waveform series data, and a D/A converter for converting the temporal waveform series data into an analog temporal waveform series signal; and a reception unit with an A/D converter for obtaining sampling-series waveform data from a power-line communication signal, a wavelet transforming device for wavelet-transforming the sampling-series waveform data into signal point data of the respective sub-carriers, and a symbol judging device for judging bit streams mapped by the signal point mapping device by inverse-mapping a plurality of these signal point data, and for synthesizing the judged bit streams with each other as a reception data series.

Abstract: A communication system includes a synchronizing signal generator that generates a synchronizing signal based on a timing of an alternating waveform in a power line, a data communicating circuit that performs the data communication, and a communication controller that controls to acquire a transmitting right utilizing a timing of the synchronizing signal and to control the communication circuit in accordance with whether or not the communication apparatus acquires the transmitting right.

Abstract: A receiving apparatus and receiving method employ a digital multi-carrier transmission technique utilizing a real coefficient wavelet filter bank in digital demodulation. The receiving apparatus may include a memory configured to store received waveform data corresponding to 2K symbols or more and a wavelet transformer configured to perform a wavelet transform based on the received waveform data stored in the memory, where K is an overlapping coefficient of a wavelet filter bank utilizing extended lapped transform (ELT).

Abstract: The invention provides a power-line carrier communication apparatus including a transmission unit with a signal point mapping device for mapping a plurality of bit streams produced from transmission data, a wavelet inverse transforming device for modulating the respective sub-carriers by wavelet waveforms which are orthogonal to each other for producing temporal waveform series data, and a D/A converter for converting the temporal waveform series data into an analog temporal waveform series signal; and a reception unit with an A/D converter for obtaining sampling-series waveform data from a power-line communication signal, a wavelet transforming device for wavelet-transforming the sampling-series waveform data into signal point data of the respective sub-carriers, and a symbol judging device for judging bit streams mapped by the signal point mapping device by inverse-mapping a plurality of these signal point data, and for synthesizing the judged bit streams with each other as a reception data series.

Abstract: The present invention relates to a transceiver and communication method involving a time division multiple transmission method, which performs data transmission among a plurality of transceivers. The transceiver includes a transmitter sending data, a receiver receiving data, a switch operable to switch among connecting the transmitter to a transmission line, connecting the receiver to the transmission line, or disconnecting both the transmitter and the receiver to the transmission line or connecting the transmission line to high impedance, and a controller operable to control the switch. The switch connects the transmitter or the receiver to the transmission line at a time that the transceiver has a relation to a communication designated by the time division multiplex transmission method.

Abstract: In case of disposing a pilot symbol in data transmission which depends on a DWMC transmission system, in a plurality of transmission symbols on a time axis, a pilot symbol, which becomes a signal of a sine wave, is configured, by giving contiguous identical data in a plurality of predetermined symbols. By transmitting a transmission signal with the use of this pilot signal, between a transmitting device and a receiving device, it is possible to carry out channel equalization by complex information which is obtained from a pilot symbol.

Abstract: When a pilot carrier is provided in data transmission according to the DWMC transmission system, continuous identical data are given in a sub-carrier pair having predetermined adjacent two sub-carriers as a unit in plural sub-carriers on a frequency axis, whereby pilot carriers P1, P2, . . . to be sine wave signals are formed. It is possible to perform clock shift compensation or the like between a transmitter and a receiver according to complex information obtained from the pilot carriers by transmitting a transmission signal using the pilot carriers between the transmitter and the receiver.

Abstract: A receiving apparatus and method for performing carrier detection in a frequency domain for a digital wavelet multi-carrier transmission. A wavelet transform of received data is performed to output complex data and then the complex data is delayed for one sampling period. Subsequently, the delayed complex data and delayed complex data are divided. A number of the divided complex data present within each of plural quadrants on orthogonal coordinates is calculated and a maximum number of data present within one of the quadrants is selected and compared with a threshold in order to decide whether the received data is intended data.

Abstract: In a multicarrier communication using a balanced transmission line such as a power line, a multicarrier communication method operable to select carriers on the basis of an SN-ratio and balancing of the transmission line is provided. Available carriers are selected in accordance with the balancing of the balanced transmission line, in which the balancing is measured at either a sending terminal or a receiving terminal or alternatively at both of them, and the SN-ratio measured between the sending terminal and the receiving terminal. More specifically, any frequency domain having poor balancing and a poor SN-ratio is treated as a non-carrier-employing domain, and consequently the available carriers are selected at other frequency domains. In addition, a modulation method having the greatest permissible multivalue is selected for each of the carriers. The carriers are selected in light of the SN-ratio and balancing, or alternatively in highest-to-lowest order of frequency.

Abstract: A communication apparatus has an A/D converter which converts an analog signal which was received, into a digital signal, a converter which converts a reception signal so as to enable handling of phase information, a carrier detector which detects presence or absence of the reception signal, a synchronous circuit which extract synchronization timing from the reception signal, an equalizer which corrects the reception signal so as to cancel influence of a transmission path, a transmission path estimator which estimates a state of a power line transmission path, and a judging unit which judges the reception signal, which was amended by the equalizer, by use of a threshold value.

Abstract: The present invention relates to a transmitter and method employing a multi-carrier transmission method, especially utilizing real coefficient wavelet filter banks. The transmitter includes a preamble data generator, a modulator, and a ramp processor. The preamble data generator generates preamble bit data, and outputs the preamble data. The modulator modulates the preamble data, generates a plurality of subcarriers, and outputs a composite wave of the time waves of the plurality of subcarriers. Subsequently, the ramp processor performs ramp processing on the composite wave with a certain delay period from a reference position of the composite wave.

Abstract: There is provided a communication network system which can set communication parameters which enable an operation under a maximum possible communication rate in a situation where a transmission path has cyclic noise/impedance fluctuations, without being influenced by such local noise/impedance fluctuations. A transmission/reception apparatus 100 transmits training packets for checking the state of the power line at two distinct points in time. Each time a training packet is received, a transmission/reception apparatus 101 analyzes SNR at each carrier frequency, and stores an SNR evaluation result. The transmission/reception apparatus 101 compares two SNR evaluation results which are obtained through two instances of a channel estimation algorithm, selects an SNR evaluation result which dictates a faster PHY rate, and transmits it to the transmission/reception apparatus 100. The transmission/reception apparatus 100 changes modulation/demodulation rules based on the received SNR analytical result.

Abstract: A receiving apparatus and method for compensating a clock-inconsistency between a transmitter and a receiver for a digital wavelet multi-carrier transmission. First and second wavelet transforms of received data are performed to output first and second transformed data and then a complex data generator generates the complex data by defining the first transformed data as in-phase components of complex information and the second transformed data as orthogonal components of the complex information and the complex data is output. Subsequently, an equalizer equalizes the complex data and outputs an equalized complex data a clock-inconsistency compensator compensates A clock-inconsistency between a receiver and a transmitter by using a result of a decision and the equalized complex data, and outputs a compensated complex data. A decision unit decides the compensated complex data, and outputs a result of the decision.

Abstract: A receiving apparatus and method for performing carrier detection in a frequency domain for a digital wavelet multi-carrier transmission. A wavelet transform of received data is performed to output complex data and then the complex data is delayed for one sampling period. Subsequently, the delayed complex data and delayed complex data are divided. A number of the divided complex data present within each of plural quadrants on orthogonal coordinates is calculated and a maximum number of data present within one of the quadrants is selected and compared with a threshold in order to decide whether the received data is intended data.

Abstract: The present invention aims at providing a multicarrier transmitter capable of processing complex information as send data.