National Institute of Information and Communications Technology, Incorporated

Denso Corporation

National Institute of Information and Communications Technology, Incorporated Administrative Agency

Communications Research Laboratory, Independent Administrative Institution

Panasonic Corporation

Kddi Corporation

Masayuki Fujise

Manabu Sawada

Hiroshi Harada

Fumihide Kojima

Minoru Okada

Yutaka Aoki

Ryuuhei Funada

Yoshihiro Suzuki

Kunihiko Sasaki

Chang-Jun Ahn

Masahiro Kuwabara

Tetsuya Kawakami

Hiroki Horiuchi

Kiyohito Yoshihara

Shinji Motegi

Katsuyoshi Sato

Hirokazu Okita

Yuji Murao

The present invention provides a radio node apparatus, a multi-hop radio system and a multi-hop radio system constructing method, capable of constructing a tree type multi-hop radio system in which mutual radio nodes determine a radio node which becomes a root node of a tree in an autonomous manner and the root node is set as a root in an autonomous manner. The radio node apparatus includes a storage unit for storing state information, used for constructing a multi-hop radio system, including information for specifying a root radio node apparatus positioned at a summit of the multi-hop radio system, with the radio node apparatus has a connection, and the number of hops from the root ratio node apparatus, a collection unit for collecting state information transmitted from surrounding radio node apparatus, and a selection unit for selecting a host connection-accepting radio node apparatus on the basis of the information for specifying the root radio node apparatus and the number of hops included in the collected state information.

Radio node apparatus, multi-hop radio system, and multi-hop radio system constructing method

A serial-parallel converterof a transmitter apparatus receives an input of a signal to be transmitted and serial-parallel-converts this to output m (m&#x2267;2) number of intermediate signals. A unitary matrix modulatormodulates the output m number of intermediate signals into a unitary matrix of m rows and m columns whose components other than diagonal components are 0 and outputs the obtained matrix. A splittersupplies the respective diagonal components of the output matrix to the input channels of an inverse Fourier transform unitas input signals. The inverse Fourier transform unitoutputs m number of inverse-Fourier-transformed signals obtained by performing inverse Fourier transform of the supplied input signals. A parallel-serial converterparallel-serial-converts the output m number of inverse-Fourier-transformed signals to output one transmission signal. A transmission unittransmits the output transmission signal. The difference between the frequency of any two channels of the inverse Fourier transform unitis equal to or larger than a predetermined coherent bandwidth.

Transmitter apparatus, receiver apparatus, transmitting method, receiving method, and program

Herein are disclosed a cable television system, mobile communication terminal, a relay apparatus, a center apparatus, and a method of providing a cable television service using the system, which enable a user operating a CATV mobile terminal () to receive a CATV service regardless of the service area of the CATV station where the user is located. When a vehicle () having a CATV mobile terminal () mounted thereon moves into a service area of a CATV station (), the CATV mobile terminal () is operated to transmit a log-in request to the CATV station (). The CATV station () is operated to inquire about the user to the subscriber station (), and the subscriber station () is operated to judge whether or not the user is authentic. Subscriber station () is operated to deliver common contents to the CATV mobile terminal () through the CATV station () when it is judged that the user is authentic.

Cable television system and method for providing cable television service using the system

A receiving unit of a receiving device receives a signal arriving thereto through a transmission path as a reception signal. A delay unit outputs a delay signal obtained by delaying the reception signal by a predetermined delay time. An estimation unit estimates a transmission path characteristic. An equalizer/demodulator compensates for the delay signal with the transmission path characteristic, demodulates the compensation result, and outputs the demodulation result as a transmission signal. A replica unit compensates for the reception signal with the transmission path characteristic, demodulates the compensation result, modulates the demodulation result, and outputs the modulation result as a replica signal. The estimation unit estimates a transmission path characteristic by comparing the reception signal with the replica signal. The predetermined delay time is equal to or smaller than a time required for the processes by the replica unit and the estimation unit.

Receiving device, receiving method, and program

A communication zone is defined by a plurality of cells, which are separated from one another and has respective fixed base stations. The base stations in the first cell and the last cell are capable of bidirectional communication with a mobile station, while other base stations are capable of unidirectional communication. The base stations are connected to a zone control station, which controls communications with the mobile station within the zone.

Radio communication using a plurality of base stations

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

The present invention is directed to improve convenience to the user. A path extending from the present location S of a mobile terminal to a destination D via a base station is calculated (S), distances between base stations on the calculated path and the present location are calculated, and the closest base station is determined as a contents delivery base station (S). Grace time for the mobile terminal to pass through the contents delivery base station is calculated. Then, scheduled time to deliver the contents to the mobile terminal is calculated (S). While monitoring a travel state of the mobile terminal (Sto S), the contents are delivered to the mobile terminal near the contents delivery base station (S).

Path predicting method for contents delivery apparatus

A receiving section outputs a received signal. An estimation section estimates transmission path characteristics, using the received signal and a modulated data signal. A compensation section outputs a compensated data signal, using the received signal and the transmission path characteristics. A demodulation section demodulates a modulated data signal, using the compensated data signal. A modulation section modulates a modulated data signal, using the demodulated data signal. The estimation section begins the estimation by comparing a result obtained by modulating known-data and a known-data portion of the received signal. The compensation section compensates for a non-compensated data signal portion, using the estimated transmission path characteristics.

Receiver, receiving method, and recording medium which records program for receiving data signals

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

A wireless communication terminal that ensures communication using a frequency band suitable for line-of-sight communication even if an obstruction is present in a wireless communication path or a status of a radio wave propagation path dynamically changes. An initial detecting section detects whether it is possible to communicate with another terminal of a master station mode. If communication is possible, a slave-mode setting section sets up a slave station mode, registers the other terminal in a master terminal storage section and transmits to the other terminal a communication indicating that a local terminal is subordinate to the master terminal. If communication is not possible, a master-mode setting section sets up a master station mode when a transmission is received indicating that the other terminal is subordinate to the local terminal. A slave terminal registration section registers the other terminal in a slave terminal storage section. A master station maintenance detection section checks regularly if communication with a slave station is possible. A slave station maintenance detection section checks regularly if communication with a master station is possible. If communication is not possible, an undetermined-mode setting section sets up an undetermined mode and a transmission section transmits a message that is received by a reception section.

Line-of-sight radio communication terminal, method and program

A multimode service radio communication apparatus, that provides a hand-held or vehicle-mounted terminal with radio communication and radio broadcasting information of a radio information and communication providing system including mobile communication systems and intelligent transport systems, includes a frequency division multiplexer that integration-converts individual radio or intermediate frequencies modulated for mobile telephones and broadcasts so that the modulated frequencies are included in a specific frequency band, and produces radio signals in the specific frequency band; supply device for supplying the radio signals; an antenna for receiving and transmitting the supplied radio signals; a shared antenna for receiving the transmitted radio signals; and terminals to which specific frequencies in the specific frequency band are selectively linked.

Multimode service radio communication method and apparatus

A channel evaluator acquires a change predicted value from a known symbol, and a compensator compensates for a first symbol using the change predicted value. A demodulator restores a portion corresponding to this symbol with another subcarrier. A replica generator acquires a transmission replica of the restored symbol. The channel evaluator performs complex division on the replica with the symbol to acquire an amplitude phase ratio. A detector compares the amplitude phase ratio with an amplitude phase ratio acquired immediately previously. In case where an elimination condition is satisfied, the detector disregards the amplitude phase ratio acquired currently and uses an immediately previous value instead, an averaging unit averages amplitude phase ratios to acquire a next change predicted value, and the compensator compensates for a next symbol using the change predicted value. Hereinafter, the sequence of processes is repeated.

Receiving apparatus, receiving method, program and information recording medium

A radio communication system between a mobile terminal station of a vehicle and a plurality of roadside fixed base stations is so constructed that communication areas of the base stations do not overlap with each other and satisfy the following two conditions. Condition (i): each communication area is defined so that there cannot be a plurality of terminal stations simultaneously. Condition (ii): it is needless to perform multiple access such as time division in the communication area and capable of affording the whole band and all the communication time allocated to one communication area to one terminal station and broad band communication becomes possible. Thus, each mobile terminal station can utilize all the frequency band allocated for service.

Growing community of inventors

Koganei, Japan

Masayuki Fujise