Denso Corporation

National Institute of Information and Communications Technology, Incorporated

Masprodenkoh Kabushikikaisha

Masahiro Kuwabara

Manabu Sawada

Minoru Okada

Masayuki Fujise

Yutaka Aoki

Hiroshi Harada

Kunihiko Sasaki

Hirotaka Naruse

Toru Sakamoto

A disclosed wireless communication device includes an antenna for communication, a transmission unit, a reception unit, a transmission/reception switchover unit, a communication control unit, a diagnosis start determination unit, a loopback path forming unit, a reception level determination unit, a reception duration determination unit, and a fault assertion unit. When a loopback path, which inputs a transmission signal outputted from the transmission unit into the reception unit, is formed by the loopback path forming unit, the reception level determination unit detects a signal level of a reception signal received by the reception unit, and determines whether or not the signal level is normal. The reception duration determination unit measures a reception duration of the reception signal in the reception unit, and determines whether or not the reception duration has exceeded a threshold value for abnormality determination.

Wireless communication device using a loopback path for fault diagnosis

A disclosed wireless communication device performing transmission and reception in a time-division manner includes an antenna, a transmission unit, a reception unit, a transmission/reception switchover unit, a first path switchover unit, a directional coupler, a second path switchover unit, a first fault diagnosis unit, and a second fault diagnosis unit. The second fault diagnosis unit causes the second path switchover unit to form a reflection signal input path; causes a second transmission signal level-adjusted for fault diagnosis to be outputted from the transmission unit; acquires a signal level of a reflection signal from the antenna inputted from the directional coupler into the reception unit; and determines whether or not a transmission radio wave is normally emitted from the antenna based on the signal level of the reflection signal.

Wireless communication device

A receiver device for a packet communication system receives a packet signal appended at its head with a known number (N) of repetition signals. A correlation value of a received signal is outputted from a normalizing correlator and compared with a threshold value in a comparator. The output of the comparator is inputted to a synchronization signal generating circuit, which includes M (&#x2266;N&#x2212;1) delay elements connected in series and an AND circuit for taking the logical product of the outputs of the delay elements. When the output of the comparator is high-level and the outputs of the M delay elementsare also all high-level, a synchronization signal at symbol timing is outputted from the AND circuit.

Signal synchronization method and receiver device for packet communication

A vehicle-vehicle communication system includes an in-vehicle wire LAN established in a vehicle. The in-vehicle wire LAN includes a plurality of devices connected by optical fiber links. A terminal for radio vehicle-vehicle communication is connected to the in-vehicle wire LAN by the optical fiber link. The terminal receives an optical digital signal in a predetermined format from the in-vehicle wire LAN. The terminal includes a light controlled oscillator and applies the received optical signal to the light controlled oscillator. The light controlled oscillator outputs a transmission signal of a frequency shifted from a predetermined frequency according to the intensity of the applied optical signal. Thus the terminal generates the transmission signal using FSK-modulation technique without converting the format of the optical signal into another format. The transmission signal is transmitted to a device in another vehicle via radio waves.

Communication system including a wire network linked with another network via radio waves

A diversity OFDM communication is performed between a base terminal and a mobile terminal, both having a horizontal polarization antenna and a vertical polarization antenna forming two transmission channels. In the base terminal, data signals to be transmitted are divided into two channels to transmit the data signals through either one of the channels having a higher transmission performance for each sub-carrier. Common pilot signals are transmitted through both channels. The data signals received by the mobile terminal are phase-adjusted using the common pilot signals. The phase-adjusted data signals in both channels are synthesized and then demodulated.

OFDM communication system and transmitter-receiver for use in the system

Communication between a stationary terminal such as an on-road terminal and a mobile terminal mounted on an automotive vehicle is performed under an OFDM system. Before transmitting data signals from the mobile terminal to the stationary terminal, a control signal indicating the number of sub-carries used in the data transmission is sent to the stationary terminal. The number of sub-carriers is decreased in accordance with increase of the moving speed to avoid deterioration in communication quality due to the moving speed increase. A modification formula and/or an error-correction-code coding rate used in the data transmission may be varied according to the moving speed in place of or together with varying the number of sub-carriers.

Communication system and device under OFDM system

A Micro-cell is formed to include a plurality of spot-cells. Communication is executed between a micro-cell base station and a mobile terminal in the micro-cell, and between a spot-cell base station and the mobile terminal in the spot cell. The micro-cell base station and spot-cell base stations are connected to an integrated base station. A signal transmitted to the micro-cell base station from the mobile terminal is transferred to the integrated base station and information transmitted to the mobile terminal is transferred to the micro-cell base station and/or spot-cell base station from the integrated base station. The respective integrated base stations are connected to a server via a dedicated backbone to enable a large-capacity transmission.

Communication system, communication method and mobile terminal

After the OFDM signal for MMAC is received by a receiving unit , an FFT processing unit converts such OFDM signal into the signal Y(l, k) in the frequency axis direction. A data extracting unit extracts a data signal Y(l, kd) and a pilot extracting unit extracts a pilot signal Y(l, kp). A complex dividing unit divides the extracted pilot signal with a pilot signal X(l, kp) having the identical amplitude and phase as that in the transmitting side. An interpolating unit performs a linear interpolation by using a transmission path response H(l, kp) of the pilot signal in order to calculate the transmission path estimation value H'(l, k) of the data signal. A complex dividing unit divides the extracted data signal with the transmission path estimation value of the data signal in order to calculate the data signal Y&#x2032;(l, kd) that is compensated in the amplitude and phase.

Growing community of inventors

Yokosuka, Japan

Masahiro Kuwabara