Showing papers by "Hiroshi Harada published in 2001"

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

Abstract: 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, communication method and mobile terminal

Abstract: 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.

Radio communication terminal, radio communication method, and program

Abstract: A radio communication terminal for radio communication using a frequency band suitable for line-of-sight communication and carried out even if an obstruction is present in the path of radio communication and even if the status of the radio wave propagation path dynamically changes. An initial judging section (102) of a radio communication terminal (101) judges whether or not the radio communication terminal (101) can communication with another communication terminal of an upper-level station mode. If it can, a lower-level station mode setting section (104) sets up a lower-level station mode, registers the another terminal in an upper-level terminal storage section (106), and sends a message to the effect that the radio communication terminal (101) is subordinate to the another communication terminal. If not, an upper-level station mode setting section (107) sets up an upper-level station mode. In the upper-level station mode, when a lower-level terminal registration section (108) receives a message to the effect that another terminal is subordinate to the radio communication terminal (101), the lower-level terminal registration section (108) registers the message in a lower-level terminal storage section (109). An upper-level station maintenance detection section (110) checks periodically if communication with a lower-level station is possible; a lower-level station maintenance detection section (111) checks if communication with an upper-level station is possible. If communication is impossible, an undetermined mode setting section (112) sets up an undetermined mode. A transmission section (113) transmits a message, and a receiving section (114) receives a message.

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

Abstract: 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.

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

Abstract: 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.

A design method of a 2-pole tapped resonator BPF with multiple attenuation poles and its miniaturization

Abstract: A design of a 2-pole bandpass filter (BPF) with multiple attenuation poles is performed. In this study, the multiple attenuation poles are realized by using the combination technique of two different tapped resonators. Miniaturization of the BPF with multiple attenuation poles is also realized on the basis of the loaded-element resonators (LERs). It is confirmed that our proposal is of great use for creating multiple attenuation poles by the few number of the resonators.

Data signal receiver compares parts of received signal corresponding to known and data signals with modulated known signal and modulated data signal parts to derive path characteristic

Abstract: The device has a receiver stage, a stage for estimating the transmission path characteristic, a distortion correction stage using the characteristic, a demodulation stage and a modulation stage. The estimating stage compares part of the received signal corresponding to a known signal with the signal resulting from modulating the known signal and compares a data signal part with part of the modulated signal corresponding to a data signal. The device has a receiver stage that receives a signal transmitted as the result of modulating a signal containing a known signal and a data signal, a stage for estimating the transmission path characteristic, a distortion correction stage using the characteristic, a demodulation stage and a modulation stage. The estimating stage compares part of the received signal corresponding to the known signal with the signal resulting from modulating the known signal and compares the data signal part with part of the modulated signal corresponding to the data signal. Independent claims are also included for the following: a method of receiving a data signal and an information recording medium that can be read by a computer containing a program.

Recepteur, procede de reception, et milieu d'enregistrement qui enregistre un programme pour recevoir des signaux de donnees

Abstract: Une section de reception (201) produit un signal recu. Une section d'estimation (202) estime les caracteristiques du chemin de transmission, en utilisant le signal recu et un signal de donnees module. Une section de compensation (203) produit un signal de donnees compense, en utilisant le signal recu et les caracteristiques du chemin de transmission. Une section de demodulation (204) demodule un signal de donnees module, en utilisant le signal de donnees compense. Une section de modulation (205) module un signal de donnees module, en utilisant le signal de donnees demodule. La section d'estimation (202) commence l'estimation en comparant un resultat obtenu en modulant des donnees connues et une partie de donnees connues du signal recu. La section de compensation (203) compense une partie du signal de donnees non compense, en utilisant les caracteristiques du chemin de transmission estimees.

A method for improving out-of-band characteristics of /spl lambda//2 microstrip line resonator bandpass filters

Abstract: Improvement of out-of-band characteristics for a bandpass filter (BPF) using /spl lambda//2 microstrip line (MSL) resonators is carried out. The basic operations of a tapped /spl lambda//2 resonator are examined theoretically and experimentally. The application to MSL resonator BPF with improved spurious responses are also examined. An extended 2-pole BPF with improved skirt characteristics and target spurious response is proposed and realized. It is confirmed that the present concept is great useful for improving out-of-band characteristics of the /spl lambda//2 resonator BPFs.

Kommunikationssystem, Kommunikationsverfahren und mobiles Endgerät

Abstract: Kommunikationssystem fur eine Kommunikation mit einem mobilen Endgerat (90), mit: einer Breitbereichszellen-Basisstation (10) zum Ausfuhren einer Kommunikation mit dem mobilen Endgerat (90) in einer Breitbereichszelle (M); einer Mehrzahl von Schmalbereichszellen-Basisstationen (20) zum Ausfuhren von Kommunikationen mit dem mobilen Endgerat (90) in einer Mehrzahl von in der Breitbereichszelle (M) enthaltenen Schmalbereichszellen (SP); und einer integrierten Basisstation (30) zum Ausfuhren von Kommunikationen mit der Breitbereichszellen-Basisstation (10) und den Schmalbereichszellen-Basisstationen (20), dadurch gekennzeichnet, das die Schmalbereichszellen-Basisstationen (20) Einwegkommunikationen mit dem mobilen Endgerat (90) ausfuhren.