Panasonic Corporation

Tadao Inoue

Yoichi Nakagawa

Takashi Fukagawa

Hirohito Mukai

Takayuki Matsui

Taro Mikami

A wireless distance measurement system and a wireless distance measurement method that measure the distance between a base station and a terminal without clock synchronization between a plurality of base stations, and without requiring input of the position relationships between a plurality of base stations. Clock phase shift section () shifts a clock that is used to generate transmission pulses is phase-shifted by a specific amount every 100 nanoseconds, and A/D conversion section () converts a signal re-radiated from terminal () to a digital signal using the shifted clock. Correlation calculation section () performs correlation calculation between the digital signal and the transmission pulse and creates a delay profile by adding digital signals in the shifted phases between same phases, and incoming wave detection section () detects peaks of the pulses in the delay profile. Distance calculation section () calculates the distance to terminal () based on the timings to transmit the pulses and the timings to detect peaks of the pulses.

Wireless distance measurement system and wireless distance measurement method

In measurement of wireless channels in an IEEE 802.11 wireless local area network (WLAN), in the case of multi-channel measurement as in North America in which eight wireless channels Ch1 through Ch8 are available, channel measurement according to a predetermined algorithm is made in which odd-numbered channels Ch1, Ch3, Ch5 and Ch7 are first measured, and if radio interference occurs in channel Ch5, channels Ch4 and Ch6 adjacent to channel Ch5 are measured. This shortens the measurement time that conventionally corresponds to measurement of the eight channels to the time of six channels, i.e., the sum of the measurement time for the odd-numbered channels and that for the channels adjacent to the interference-occurring channel.

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Hyogo, Japan

Tadao Inoue