Hitachi-kokusai Electric Inc.

Nec Corporation

Hitachi Denshi Kabushiki Kaisha

Kokusai Denki Electric Inc.

Tatsuhiro Nakada

Kei Ito

Hiroki Kato

Hiroyuki Takesue

Daiki Hoshi

Nobuo Tsukamoto

Keisuke Yamamoto

Toshiyuki Akiyama

Yohei Hasegawa

Atsushi Miyashita

Seiichi Sano

Satoru Ejima

Itsuo Ishida

Mikio Fujikura

Hisao Koda

The present invention allows a gain control to be appropriately effected even when a frame including no preamble signal block is used for wireless communications. The following processes are effected in a transmission power control unitof a transmission unit. Specifically, an automatic transmission gain control unitmultiplies a transmission signal by a gain value that is the difference between the power of a signal loop-backed from a power amplifierand the power of the transmission signal. A fixed transmission gain multiplying unitmultiplies the transmission signal by a predetermined gain value or by the gain value used in the automatic transmission gain control unitduring the preceding frame. A selection unitselects the transmission signal as gain-controlled by the automatic transmission gain control unitin a case of a preamble signal block being included in the frame of the transmission signal and selects the transmission signal as gain-controlled by the fixed transmission gain multiplying unitin a case of no preamble signal block being included in the frame of the transmission signal.

Wireless communication system, transmission method and reception method

[Problem] To propose a technology capable of appropriately demodulating, in a receiving device, a plurality of pieces of data multiplexed through the quasi-synchronous LDM method. [Solution] A transmission device generates a UL modulated signal by using an IFFT process of Npoints, generates an LL modulated signal by using an IFFT process of Npoints different from the Npoints, and transmits signals obtained by timing-adjusting the modulated signals such that the start timings thereof coincide with each other in a predetermined cycle, and combining the timing-adjusted signals at a predetermined power ratio. In addition, the receiving device performs an Npoint FFT process on the reception signal from the transmitting device, reproduces UL and generates UL reception replica, on the basis of the result, and performs an Npoint FFT process on a signal obtained by subtracting the UL reception replica from the reception signal, and reproduces LL on the basis of the result.

Data transmission system for multiplexing a plurality of pieces of data in a layered division multiplexing (LDM) method and transmitting multiplexed data, reception device used in the data transmission system, and data transmission method therefor

An optical transmitter includes: a plurality of client ports configured to receive a client signal from an end user device; a plurality of line ports configured to generate a line signal in which the client signal is stored, and transmit the line signal to an optical receiver; a switch configured to connect the plurality of client ports with the plurality of line ports; and a label provider configured to provide the client signal with a label for identifying a transmission destination in the optical receiver.

Optical transponder

In order to reduce the number of wires between blades, this blade device is provided with: a control blade for sending first information, which is at least one of control information for controlling a blade to be controlled and monitor information for monitoring the blade to be controlled, to the blade to be controlled by wireless communication; and the blade to be controlled which performs a process in accordance with the first information that has been received.

Blade device

In a base station, a signal synchronization unit detects a received timing of a signal from a mobile station. A correlation position protection unit corrects the received timing on the basis of time from a transmitting timing at which a signal transmitting operation to the mobile station is started to the received timing. A transmitting timing generation unit generates, on the basis of the received timing after the correction, a transmitting timing at which a subsequent signal transmitting operation to the mobile station is started. Further, an FB frame generation unit generates frame period information that indicates a correction value by the correlation position protection unit, and a transmitting processing unit transmits, to the mobile station, a signal including the frame cycle information in response to the generation of the transmitting timing.

Wireless communication system and wireless communication device

A communication device configured to include a communication unit a monitoring unit, a control unit, and an authentication unit. The communication unit transmits and receives an optical signal to and from an opposed device via a transmission line. The monitoring unit monitors a transfer state of the transmitted optical signal. The control unit transmits a signal based on a dummy pattern instead of actual data when the monitoring unit detects that a failure occurs in transfer of the optical signal. The authentication unit authenticates start of transmission of a signal based on the actual data, when the monitoring unit detects elimination of the failure, while the signal based on the dummy pattern is being transmitted. Moreover, the control unit transmits the signal based on the actual data instead of the dummy pattern when the start of transmission is authenticated by the authentication unit.

Communication device and communication method

A terminal apparatus () is provided with a coding unit (), a decoding unit (), and a control unit () for controlling the coding unit and the decoding unit individually. Under control of the control unit, the coding unit codes a payload, a first number of error corrections (), and identification information () that are to be transmitted, on the basis of a method indicated by the already-transmitted identification information to thereby generate first coded data. The decoding unit decodes newly-received second coded data on the basis of a method indicated by the identification information included in a decoding result of the already-received second coded data.

Terminal apparatus, control method therefor, and recording medium in which control program for terminal apparatus is stored

A reception device including reception antennas is provided. In the reception device, a demodulation unit is configured to calculate, for each of a plurality of antenna combinations of the reception antennas, log likelihood ratios of coded bits of error correction code obtained from reception signals of the reception antennas. A mutual information amount calculation unit is configured to calculate an average mutual information amount based on the log likelihood ratios corresponding to each of the antenna combinations. An antenna combination selection unit is configured to output determination information for specifying one of the antenna combinations for which the average mutual information amount is the maximum. A signal selection unit is configured to select the log likelihood ratios corresponding to the specified antenna combination based on the determination information, and a decoding unit is configured to decodes the selected log likelihood ratios.

Reception device and wireless communication system

A peak power reduction device includes a unit for dividing digital information to be transmitted into a plurality of streams; a unit for selecting the modulation level of the streams and distribution of transmission power according to a transmission state; a unit for performing singular-value decomposition on the transmission path characteristic of a streams and precoding the resultant data by a right singular value matrix; a unit for performing complex mapping on the subcarrier of a stream according to the modulation level; a unit for converting a complex mapping signal into a time domain signal; a first unit for storing a conversion result as a time domain signal; a second unit for calculating a peak time signal exceeding a predetermined threshold value from a peak value, if any exists, that exceeds a prescribed threshold value for the amplitude of the time domain signal.

Peak power reduction device in communication system

Disclosed is a reception apparatus that has solved a problem that fluctuations cannot be followed immediately after a commencement of turbo equalization in a high-speed fading environment. A reception apparatus includes a soft interference canceller, an MMSE equalizer, a likelihood calculator, a de-interleaver, an SISO decoder, an information bit hard decision unit, a subtracter, an interleaver, a soft estimation value calculator, a zero storage unit, a known signal memory unit, a transmission path estimator, and a plurality of switches. At the time of equalization, the transmission path estimator uses, as a reference signal, a known signal stored in the known signal memory unit or an output of the MMSE equalizer. Meanwhile, at the time of a first equalization, the soft interference canceller is given a '0' value from the zero storage unit as a reference signal.

Reception apparatus performing turbo equalizations

An optical signal transmitted by another terminal device that was used for compensation could be received by a device that is not the intended destination of said optical signal, resulting in the problem that confidentiality cannot be guaranteed for the information in said optical signal. This optical reception device is characterized by the provision of the following: a receiving means via which wavelength-multiplexed signal light is inputted; and a transmitting means that, in accordance with an identifier in an optical signal of a prescribed wavelength in the inputted wavelength-multiplexed signal light, forwards said optical signal.

Optical reception apparatus, optical transmission apparatus, optical communication system, optical communication method, and storage medium storing program

An object of the present invention is to generate a soft estimation value where missing of bit information is avoided and to implement turbo equalization processing in a wireless transmission apparatus and a wireless transmission system where termination processing is not performed in an error correction coding part and interleave processing over frames is performed. A wireless transmission system of the present invention includes a transmission apparatus and a reception apparatus. The transmission apparatus includes an error correction coding unit, a first interleave unit, a second interleave unit, and a digital modulation unit. The reception apparatus includes a unit that detects a reception signal, a demapper unit, a second deinterleave unit, a unit to store a received bit logarithm of likelihood ratio in a frame buffer, a frequency interleaver data extraction part that extracts data of a predetermined period, a decoding part, and a hard decision part.

Wireless transmission system and reception device

A first terminal-side routing control deviceis placed between a first communication networkand a first communication terminal. A second terminal-side routing control deviceis placed between a second communication networkand a second communication terminal. The first terminal-side routing control deviceincludes a first via information setting unitfor including, in data received from the first communication terminal, information for specifying a routing control deviceplaced on one side of a long-distance transmission pathas a via device. The second terminal-side routing control deviceincludes a second via information setting unitfor including, in data received from the second communication terminal, via information for specifying a routing control deviceplaced on the other side of the long-distance transmission pathas a via device.

Transmission system, routing control device and method for controlling routing

A receiver includes a first and a second amplification unit for amplifying a first and second received signals received by antenna units; a level variation detection unit for performing gain control of the first amplification unit; a maximum received signal level extraction unit for performing gain control of the second amplification unit; and a first and a second frequency conversion unit. The receiver further includes an interference frequency detection unit for detecting a frequency of interference in the second received signal; an interference frequency cut-off unit for cutting off the frequency of the interference; demodulation units for demodulating the respective received signals; noise amplitude calculation unit for calculating noise amplitudes from the respective received signals; equalizing units for correcting amplitudes and phases of the respective received signals; and a combining unit for combining demodulation results from the respective received signals on the basis of noise amplitude detection results.

Receiver

The present invention makes it possible to maintain the continuity of reception detection level and adjust the direction of a reception antenna even under the condition that the reception electric field is low and clock timing synchronization at a C/N ratio of 0 dB or less is lost. QAM modulation including a pilot carrier has higher correlativity in one symbol (1152 samples) correlation, and differential modulation with no pilot has higher correlativity in effective symbol (1024 samples) correction. Detection circuits are provided separately for the QAM modulation and the differential modulation, and in the differential modulation, autocorrelation with a 1024 FFT clock delay signal is performed. The higher of the respective correlation results is selected in the final stage.

Growing community of inventors

Tokyo, Japan

Tatsuhiro Nakada