Nippon Telegraph and Telephone Corporation

Fuji Television Incorporated

Hiroshi Sakamoto

Tomoaki Ogawa

Makoto Umeuchi

Hiroyuki Nakamura

Shinya Otsuki

Junichi Iwatani

Masayoshi Nabeshima

Tomoki Murakami

Masaru Miyamoto

Masamichi Hosoda

Tadashi Mori

Yasushi Hanakago

Chiharu Kamise

A predetermined radio base station and subordinate radio terminals detect signals (beacons) regularly transmitted by other radio base stations, transmit information about radio channels and base station identifiers of the detected signals, and position information about the radio terminals to an interference area detection device to aggregate the information and the position information as a base station-base station detection list and a terminal-base station detection list. The interference area detection device compares the lists, determines, for each of positions of the subordinate radio terminals to the predetermined radio base station, whether both of the signal of the predetermined radio base station and a signal of another radio base station, which cannot be detected by the predetermined radio base station, are detected or not, and determines that a position where both of the signals are detected is within an interference area if the predetermined radio base station and the other radio base station detected at the position use the same radio channel.

Interference area detection method for wireless communication system, interference area detection system, interference area detection device, and interference area detection program

Provided is a position estimation method in which a measurement signal and a response signal are transmitted and received between multiple n wireless stations respectively provided with known antennas installed at known positions different from each other and a wireless terminal station provided with a terminal antenna, RTT, which is a round-trip delay time of the transmission and reception, and RSSI, which is a strength of received radio waves of the signals, are measured, and a position of the wireless terminal station is estimated. The method includes: obtaining, as the position of the wireless terminal station, a solution of simultaneous equations of an RTT evaluation function ffor evaluating the estimate value of the position of the wireless terminal station that is estimated based on the RTT measured between the wireless terminal station and the known antenna i (i=1, 2, . . . , n), and an RSSI evaluation function ffor evaluating the estimate value of the position of the wireless terminal station that is estimated based on the RSSI, or a value obtained by searching for an estimate value so that an error evaluation function fobtained by combining the RTT evaluation function and the RSSI evaluation function is minimum.

Position estimation method, position estimation system, position estimation server, and position estimation program

A plurality of access points configured to communicate with a subordinate wireless LAN terminal, an information collecting device configured to collect a frame respectively transmitted and received between the plurality of access points and the wireless LAN terminal, and extract information on communication quality of an access point of the plurality of access points from a header of the frame, and an information collecting server configured to acquire the information on the communication quality of the access point from the information collecting device, analyze the information to determine whether the communication quality is good or bad for each of the plurality of access points, and execute processing of externally displaying or notifying a result that is determined are included.

Wireless LAN communication system, access point communication quality determination method, and information collection server

There are provided a plurality of radio devices detecting an interference source signal transmitted by an interference source and generating pieces of air time information showing whether the interference source signal exists or not for each predetermined time unit; and an aggregation device estimating air time of the interference source by acquiring the pieces of air time information from the plurality of radio devices and aggregating/integrating the acquired pieces of air time information for each predetermined unit time, matching timings.

Wireless communication system, aggregation device, interference source air time acquisition method, and interference source air time acquisition program

A wireless base station and a first wireless terminal include means for collecting first wireless performance information regarding wireless communication in both a downstream direction and an upstream direction and transmitting the first wireless performance information to a wireless performance measurement device. The wireless base station and a second wireless terminal include means for collecting second wireless performance information regarding wireless communication in both the downstream direction and the upstream direction and transmitting the second wireless performance information to the wireless performance measurement device. The wireless performance measurement device includes means for obtaining a first comparison result by comparing the first wireless performance information regarding the upstream direction and the downstream direction, obtaining a second comparison result by comparing the second wireless performance information regarding the upstream direction and the downstream direction, and determining the location where an abnormality occurred in accordance with a result of a comparison of the first comparison result and the second comparison result. The location is determined from among the wireless base station, the first wireless terminal, the second wireless terminal, and a wireless propagation environment between the wireless base station and the first wireless terminal and between the wireless base station and the second wireless terminal.

Radio performance measurement system, radio performance measurement method, radio performance measurement device, and radio performance measurement program

There are provided an information collecting device configured to collect a frame A transmitted and received between a wireless LAN base station that is an evaluation target and a wireless LAN terminal subordinate to the wireless LAN base station that is the evaluation target and a frame B transmitted and received between a wireless LAN base station that is a non-evaluation target and a wireless LAN terminal subordinate to the wireless LAN base station that is the non-evaluation target, and extract radio information on communication quality of each of the wireless LAN base stations from a header of a corresponding one of the frames A and B, and a wireless LAN communication quality estimation device configured to acquire, from the wireless LAN base station that is the evaluation target, information on the number of currently connected wireless LAN terminals, acquire, from the information collecting device, the radio information on the communication quality of each of the wireless LAN base stations, and analyze the information to estimate whether the communication quality of the wireless LAN base station that is the evaluation target is good or bad.

Wireless LAN communication quality estimation method, wireless LAN communication quality estimation system, information collection device, and wireless LAN communication quality estimation device

In a wireless information collecting method executed by at least one user terminal device that measures wireless information used in a site survey and a server device that stores the wireless information and performs the site survey, the user terminal device performs a step of periodically measuring a current position and transmitting positioning information indicating the current position to the server device, and a step of measuring the wireless information in accordance with a wireless information measurement number instructed by the server device and transmitting wireless information including a position and time to the server device. The server device performs a step of associating a position of the user terminal device and time with the wireless information and creating and updating a condition map indicating a wireless information measurement number at a position and time at which a site survey is performed, and a step of collating the current position of the user terminal and the time with the condition map and transmitting an instruction for the wireless information measurement number based on the current position of the user terminal device and the time to the user terminal device.

Radio information collection method and radio information collection system

An object is to enable high-accuracy position estimation of a wireless terminal station by efficiently performing connection between a wireless base station and the wireless terminal station using multiple distributed antennas. A position estimation apparatus configured to estimate a position of a wireless terminal station between a wireless base station that can perform transmission and reception by switching between a plurality of distributed antennas arranged in a distributed manner via cables with known lengths, and the wireless terminal station configured to communicate with the wireless base station, includes: a means 1 for measuring a no-delay RTT or measuring a statistical processing RTT when the wireless base station exchanges a measurement signal and a response signal with the wireless terminal station in each of the distributed antennas and measures an RTT, which is a round trip time between the wireless base station and the wireless terminal station, a delay time having been removed from the no-delay RTT using a reception time of the measurement signal and a transmission time of the response signal, and the statistical processing RTT being measured using statistical processing for making the delay time constant using a plurality of instances of exchanging a measurement signal and a response signal; and means 2 for estimating the position of the wireless terminal station based on the no-delay RTT or the statistical processing RTT of each of the distributed antennas.

Position estimation method and position estimation apparatus

A key signal such as a TV signal or the like is provided to a liquid crystal TV panel, by which an image of a desired shape is displayed on the display screen of the liquid crystal TV panel at a position where an optical effect is intended to be produced. Light from a light source is applied to the liquid crystal TV panel, transmitted or reflected light therefrom is incident to an optical filter, and the image of transmitted light therefrom is picked up by a TV camera. The video output of the TV camera is mixed, by a video mixer, with a video signal of the image to be added with the optical effect.

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Musashino, Japan

Hiroshi Sakamoto