Abstract: With the objective of enhancing receiving performance of a receiver with respect to pulse signals spread by spread codes, the receiver comprises an RF front-end section which performs amplification, an AD converter section which AD-converts signals outputted from the RF front-end section, a baseband section which inversely spreads the output of the AD converter section and performs signal detection and demodulation thereon, a reception environment measuring section which measures reception environment using the input signals of the baseband section, and a parameter setting section which sets parameters for respective parts on the basis of signals outputted from the reception environment measuring section. The parameter setting section sets the parameters for the respective parts to the optimum according to the environmental condition measured by the reception environment measuring section.

Abstract: In a system for measuring a time difference of arrival of signals for positioning, an accurate time difference is measured by a receiver which is reduced in power consumption, size, and cost. The system comprises a node (under measurement) for transmitting a positioning signal, a reference station for transmitting a reference signal, and a plurality of access points for receiving the positioning signal and reference signal, and a server connected to the plurality of access points through a network. Each of the plurality of access points measures a time difference between the reception of the positioning signal and the reception of the reference signal, and a frequency deviation from the reference station, using a clock signal and a signal for shifting the clock signal, and the server calculates the position of the node based on the measured time difference and frequency deviation.

Abstract: In a wireless network system, the nodes share a frequency hopping pattern. A method comprises providing a channel list table which includes, for each transmitting node, one or more channel lists, each channel list containing conditions of the channels of the shared frequency hopping pattern that include at least one available channel for communications with a target node; selecting a channel of a next allocated time slot from the shared frequency hopping pattern at the transmitting node; selecting the channel list for the target node from the channel list table, to which the transmitting node transmits; checking if the selected channel is available based on the selected channel list; setting the selected channel at the transmitting node if the selected channel is available; and calculating a substitute channel from the channel list if the selected channel is not available.

Abstract: In a system for measuring a time difference of arrival of signals for positioning, an accurate time difference is measured by a receiver which is reduced in power consumption, size, and cost. The system comprises a node (under measurement) for transmitting a positioning signal, a reference station for transmitting a reference signal, and a plurality of access points for receiving the positioning signal and reference signal, and a server connected to the plurality of access points through a network. Each of the plurality of access points measures a time difference between the reception of the positioning signal and the reception of the reference signal, and a frequency deviation from the reference station, using a clock signal and a signal for shifting the clock signal, and the server calculates the position of the node based on the measured time difference and frequency deviation.

Abstract: An invention for estimating the first path of an arrival signal by a method and device with a simple structure and lower power consumption. In this method, the nominal pulse repetition frequency or its integer multiple are A/D converted at a frequency less than the multiplicative inverse of the pulse width, the AD conversion timing is offset by time resolution ?t and the receive signal measured, data stored in a RAM, and the first path output time is estimated based on sequentially rearranging of the stored waveform data.

Abstract: In a system for measuring a time difference of arrival of signals for positioning, an accurate time difference is measured by a receiver which is reduced in power consumption, size, and cost. The system comprises a node (under measurement) for transmitting a positioning signal, a reference station for transmitting a reference signal, and a plurality of access points for receiving the positioning signal and reference signal, and a server connected to the plurality of access points through a network. Each of the plurality of access points measures a time difference between the reception of the positioning signal and the reception of the reference signal, and a frequency deviation from the reference station, using a clock signal and a signal for shifting the clock signal, and the server calculates the position of the node based on the measured time difference and frequency deviation.

Abstract: The present invention conducts the initial synchronization acquisition of the rapid and high precision ultra-wideband signal without complicatedness of hardware and increase in power consumption. For this purpose, a communication apparatus for exchanging information with an intermittent pulse train signal searches all phases among the pulses in the predetermined search resolution in the process to acquire initial synchronization of the input pulse, estimates the region where the peak phase of the largest output value exists, narrows the region where the peak phase exists up to the predetermined range by repeating the search for all phases in the estimated region in the next step, and conducts acquisition of detailed synchronization in the estimated region. In every step, the threshold value for judging existence of signal or a gain in the analog circuit is controlled for each step.

Abstract: To correct a sensor data acquisition time with a simple hardware configuration, provided is a wireless sensor-network system including: a base station; and a plurality of sensing terminal nodes, the base station transmitting a beacon at predetermined intervals to the plurality of sensing terminal nodes, the plurality of sensing terminal nodes measuring data and transmitting, based on a reception of the beacon transmitted from the base station, the sensor data thus obtained to the base station, in which the plurality of sensing terminal nodes obtain, based on an internal clock, a time at which the beacon is received and transmit the time to the base station, and the base station corrects, based on the reception time transmitted from each of the plurality of sensing terminal nodes, the sensor data acquisition time.

Abstract: With the objective of enhancing receiving performance of a receiver with respect to pulse signals spread by spread codes, the receiver comprises an RF front-end section which performs amplification, an AD converter section which AD-converts signals outputted from the RF front-end section, a baseband section which inversely spreads the output of the AD converter section and performs signal detection and demodulation thereon, a reception environment measuring section which measures reception environment using the input signals of the baseband section, and a parameter setting section which sets parameters for respective parts on the basis of signals outputted from the reception environment measuring section. The parameter setting section sets the parameters for the respective parts to the optimum according to the environmental condition measured by the reception environment measuring section.

Abstract: A communications apparatus which ensures a predetermined communication quality even when an external environment changes dynamically, and enhances a throughput for overall system, thereby achieving favorable transmission efficiency. A communications apparatus having a receiver and a transmitter and carries out sending/receiving by use of a pulse train is provided with a communication environment measuring section to measure a communication status based on an output from the receiver. The transmitter is configured such that it transmits a transmission signal, in which the transmission rate of data to be transmitted and the pulse energy have been controlled in association with each other, according to a result of the measurement.

Abstract: With the objective of enhancing receiving performance of a receiver with respect to pulse signals spread by spread codes, the receiver comprises an RF front-end section which performs amplification, an AD converter section which AD-converts signals outputted from the RF front-end section, a baseband section which inversely spreads the output of the AD converter section and performs signal detection and demodulation thereon, a reception environment measuring section which measures reception environment using the input signals of the baseband section, and a parameter setting section which sets parameters for respective parts on the basis of signals outputted from the reception environment measuring section. The parameter setting section sets the parameters for the respective parts to the optimum according to the environmental condition measured by the reception environment measuring section.

Abstract: A pulse generator for UWB transmission, lower power consumption, and suppression of LO leakage by nonuse of the LO signal. The pulse generator includes a clock generator (CLK) for giving clock of a predetermined period; a delay circuit (DLY) equipped with a function of controlling a delay time and for delaying the clock; a square-wave pulse generation circuit (SWPG) that receives information being spread by a spread code and modulates phases of square wave pulses that have a pulse width corresponding to a differential delay for one stage of the delay circuit; and an amplitude control unit (AMPC) that outputs an impulse sequence having the pulse width of the square wave in a predetermined amplitude and combines the impulses; and outputs pulses that have a predetermined envelope form.

Abstract: A radio communication system having an interference reduction function and enabling random access is constructed without complicating a terminal structure. A base station has an interference signal detection function, performs interference signal detection intermittently and transmits a beacon signal when no interference signal is detected. A terminal starts up from a sleep mode before transmitting data, performs reception waiting, transmits data only immediately after reception of the beacon signal, transits to the sleep mode again if the beacon signal is not received and repeats the abovementioned sequence after a predetermined time elapses.

Abstract: A node location system for detecting a node by receiving two or more access points. The node location system includes a node, a reference station, multiple access points, a server, and a network. After receiving a location signal, the reference station sends a reference signal, and the access points receive a position measurement signal and a reference signal, and detects a specified pattern from the received location signal and reference signal, and measures the time from detecting the specified pattern from the location signal until detecting the time from the reference signal, and sends the signal-receive-time information including that measured time to the server, and the server calculates the difference between the time the reference station received the location signal and the time that the access points received the location signal, and then calculates the node position based on this calculated differential.

Abstract: A positioning system having a node (subject to positioning) transmitting a positioning signal; a reference station transmitting a reference signal; at least three base stations having a receiving part receiving the aforementioned positioning signal and the aforementioned reference signal; and a server connected to the base stations by a network; wherein the aforementioned server measures, using a clock signal and a signal shifting the concerned clock signal, the time difference with which the aforementioned positioning signal and the aforementioned reference signal are received by the aforementioned plurality of base stations as well as the frequency deviation with the aforementioned base stations; decides whether to carry out a correction with respect to the aforementioned measured time difference, on the basis of the measurement result of the aforementioned positioning signal; and computes the position of the aforementioned node, based on the aforementioned time deviation for which appropriate processing

Abstract: An invention for estimating the first path of an arrival signal by a method and device with a simple structure and lower power consumption. In this method, the nominal pulse repetition frequency or its integer multiple are A/D converted at a frequency less than the multiplicative inverse of the pulse width, the AD conversion timing is offset by time resolution ?t and the receive signal measured, data stored in a RAM, and the first path output time is estimated based on sequentially rearranging of the stored waveform data.

Abstract: A node position measuring system according to this invention includes a node, a reference station, base stations, a server that calculates a position of the node, and a network. The reference station includes a positioning signal reception module and a reference signal generation module that transmits a reference signal after the positioning signal reception module receives the positioning signal. Each of the base stations includes a signal reception module, a reception time measuring module that detects specific patterns from the positioning signal and the reference signal received by the signal reception module to measure a detection time, and a communication module that transmits time information, which is generated from the time measured by the reception time measuring module, to the server. The server includes a position calculation module that calculates the position of the node based on the time information transmitted from the base station.

Abstract: A location system of a configuration that facilitates initial introduction, maintenance, and system expansion. A terminal location system basically has at least (N+1) base station (here, N=1 to 3) and a location server and finds a position of a terminal performing wireless communication in N-dimensional coordinates. Further, the terminal location system calculates distances among the at least (N+1) base stations, finds relative coordinates of the base stations, evaluates the obtained relative coordinates, determines switching to terminal location processing of finding the position of the terminal, and finds the position of the terminal using propagation times of radio signals transmitted/received among the terminal and the base stations and the obtained relative coordinates of the base stations.

Abstract: The present invention conducts the initial synchronization acquisition of the rapid and high precision ultra-wideband signal without complicatedness of hardware and increase in power consumption. For this purpose, a communication apparatus for exchanging information with an intermittent pulse train signal searches all phases among the pulses in the predetermined search resolution in the process to acquire initial synchronization of the input pulse, estimates the region where the peak phase of the largest output value exists, narrows the region where the peak phase exists up to the predetermined range by repeating the search for all phases in the estimated region in the next step, and conducts acquisition of detailed synchronization in the estimated region. In every step, the threshold value for judging existence of signal or a gain in the analog circuit is controlled for each step.

Abstract: In a system for measuring a time difference of arrival of signals for positioning, an accurate time difference is measured by a receiver which is reduced in power consumption, size, and cost. The system comprises a node (under measurement) for transmitting a positioning signal, a reference station for transmitting a reference signal, and a plurality of access points for receiving the positioning signal and reference signal, and a server connected to the plurality of access points through a network. Each of the plurality of access points measures a time difference between the reception of the positioning signal and the reception of the reference signal, and a frequency deviation from the reference station, using a clock signal and a signal for shifting the clock signal, and the server calculates the position of the node based on the measured time difference and frequency deviation.