Nec Corporation

Mitsubishi Electric Corporation

Nec Communication Systems, Ltd.

Shinji Masuda

Toshiyuki Tamura

Satoshi Sasaki

Kazuaki Nakajima

Akinori Taira

Kazumasa Suzuki

Hiroyasu Sano

Yukihiro Hara

Shusaku Umeda

Kenki Takagi

Akinori Nakajima

Hidemi Ishikawa

Masayuki Shinsho

Yohei Miyama

Tomonori Kumagai

A radio transmission device includes: a known signal generating unit that generates a first known signal and a second known signal mapped in such a manner that subcarriers for transmitting a first signal not being 0 do not overlap with each other in symbols of one time band; an IDFT unit that converts the first known signal and the second known signal from a frequency domain signal into a time domain signal; a GI inserting unit that inserts a guard interval into the first known signal and the second known signal converted into time domain signals; a transmission antenna that transmits the first known signal in which the guard interval is inserted; and a transmission antenna that transmits the second known signal in which the guard interval is inserted.

Radio transmission device, radio reception device, radio communication device, radio communication system, radio transmission method, control circuit, and recording medium

A base station, which is a transmission device according to the present invention, includes a space-time block coding unit that performs space-time block coding on a transmission symbol to generate a transmission block, a differential unit that performs a differential operation on the transmission block, a code multiplication unit that multiplies the transmission block by a code, a selection unit that selects one of the transmission block after the differential operation and the transmission block after the code multiplication, and wireless transmission units that transmit the transmission block selected.

Transmission device, receiving device, and wireless communication system

An object is to provide a monitor device capable of reducing threat of DoS attacks on a mobile network. A monitor device () according to the present invention includes a signal monitor unit () for estimating a specific base station communicating with a communication terminal () attacking a mobile network according to the number of times an ATTACH procedure is rejected, in which the ATTACH procedure is for registering information about a communication terminal () communicating with a base station () in a communication device () located in the mobile network, and a base station control unit () for causing the specific base station to determine whether to execute the ATTACH procedure related to a communication terminal served by the specific base station according to communication terminal identification information set in a signal transmitted from the communication terminal served by the specific base station.

Monitor device, base station, monitoring method, control method, and non-transitory computer readable medium

A transmitter includes: a first mapping unit to allocate modulation symbols to orthogonal frequency division multiplexing subcarriers; a first differential block coding unit to perform differential block coding on a part of the modulation symbols allocated; a second differential block coding unit to perform, by using output of the first differential block coding unit as a start symbol, differential block coding on a remaining modulation symbol excluding the part of the modulation symbols subjected to differential block coding by the first differential block coding unit; and a second mapping unit to convert output of the second differential block coding unit into a transmit signal that is transmitted from a plurality of antennas.

Transmitter, control circuit, recording medium, and subcarrier mapping method

A base station includes a wakeup signal transmission part transmitting transmission signal information to a wireless terminal by wireless communication. The transmission signal information includes a wakeup signal starting a given function included by the wireless terminal. The wakeup signal transmission part transmits the transmission signal information including connection information in addition to the wakeup signal to the wireless terminal. The connection information is information for causing the wireless terminal of a destination of transmission of the wakeup signal to connect by wireless communication using the given function.

Base station, wireless terminal, communication system, communication method, and program

The present invention provides a multiprocessor ATM exchange which permits an ATM exchange to be configured with multiple processors to provide high capacity. The CLP state management section of the common signaling processor collects load state information from the CLP load monitoring section of call control processors to manage the load state thereof, and manages the normal or abnormal state of the call control processors. The signal floating function section, when receiving an initial address message, selects a call control processor suitable for processing said call based on the contents of the CLP state management section. On receiving the initial address message, the B-ISUP body of a selected call control processor generates an origination signal identifier from an incoming internal call reference number and the clp number of the call control processor and appends the signal identifier to the signal to send it.

Multiprocessor ATM exchange

A charge detecting circuit includes a plurality of photodiodes, and a first multiplexer having a plurality of inputs connected to the photodiodes, respectively and operative to selectively connect one of its inputs to its output. Further, there are provided dummy capacitors of the same number as that of the photodiodes, each of the dummy capacitors having substantially the same capacitance as one corresponding photodiode, and a second multiplexer having a plurality of inputs connected to the dummy capacitors respectively, and operative to connect one of its inputs to its output. A differential amplifier is connected at its first input to the output of the first multiplexer and at its a second input to the output of the second multiplexer, so as to generate a photodetection signal.

Charge detecting circuit

A constant voltage generator includes a resistance adjustable resistor having a series connection of a main resistor and sub-resistors, a circuit cooperating with the series connection to produce a constant voltage, a plural number of transistors having a collector-emitter path connected to corresponding one of the sub-resistors, and a plural number of semiconductor memories applying voltages to bases of the transistors, respectively, in accordance with stored information, whereby the resistance of the resistance adjustable resistor is adjusted by the stored information to control the output constant voltage.

Constant voltage generator using memory transistors

An operational amplifier has a bias stage, a sampled differential stage, and a push-pull cascode stage. Unlike the conventional operational amplifier, the sampled differential stage is adopted in place of a differential stage has switches and capacitors. An input signal is transferred to the push-pull cascode stage through the capacitors in cooperation with the switches operated in response to clock signals phase-shifted by 180.degree., thereby applying optimal bias voltages to the push-pull cascode stage and providing a wide frequency bandwidth.

Operational amplifier

A leakage current between the inverting input terminal and the output terminal of an operational amplifier having a switch between the two terminals is prevented from flowing by equalizing the potentials at the two terminals of the switch when it is open. This is accomplished by dividing the switch into two and inserting an additional switch between the intermediate node of the divided two switches and a reference potential point.

Growing community of inventors

Tokyo, Japan

Shinji Masuda