Short-distance radio communication system for vehicle

Patent metadata

Field	Value
Publication number	US-2016205498-A1
Application number	US-201615074012-A
Country	US
Kind code	A1
Filing date	Mar 18, 2016
Priority date	Oct 2, 2013
Publication date	Jul 14, 2016
Grant date	—

Abstract

This short-distance radio communication system for a vehicle includes an in-vehicle unit having more than one antenna and a portable unit performing radio communications with the in-vehicle unit. The in-vehicle unit transmits a first burst together with a call signal for calling the portable unit through a first antenna, and transmits a second burst subsequent to the first burst through a second antenna. The portable unit receives the signals transmitted from the in-vehicle unit, measures respective received signal strength indicators from the first burst and the second burst contained in the received signals, and responds to the in-vehicle unit according to results of comparing the respective indicators with given thresholds.

First claim

1 . A short-distance radio communication system for a vehicle, comprising:
an in-vehicle unit having a plurality of antennas; and a portable unit performing radio communications with the in-vehicle unit, wherein the in-vehicle unit has a first antenna as an in-vehicle antenna and a second antenna as an out-vehicle antenna, the in-vehicle unit transmitting a first burst together with a call signal for calling the portable unit through the first antenna, the in-vehicle unit transmitting a second burst subsequent to the first burst through the second antenna, and wherein the portable unit does not respond to the call signal to the in-vehicle unit (1) if a first received signal strength indicator measured from the first burst does not exceed a predetermined first threshold, or (2) if the first received signal strength indicator exceeds the predetermined first threshold and a second received signal strength indicator measured from the second burst exceeds a predetermined second threshold, when the portable unit receives signals transmitted from the in-vehicle unit, measures respective received signal strength indicators from the first burst and the second burst contained in the received signals, and responds to the call signal to the in-vehicle unit according to results of comparing the respective indicators with predetermined thresholds.

2 . The short-distance radio communication system for a vehicle of claim 1 ,
wherein the in-vehicle unit further includes a third antenna, which is an out-vehicle antenna different from the second antenna, and wherein the portable unit does not respond to the call signal to the in-vehicle unit (3) if the first received signal strength indicator exceeds the predetermined first threshold, the second received signal strength indicator does not exceed the predetermined second threshold, and a third received signal strength indicator measured from a third burst exceeds the predetermined second threshold.

3 . The short-distance radio communication system for a vehicle of claim 2 , wherein one of the second antenna and the third antenna is an out-vehicle driver's seat door handle antenna, and the other is an out-vehicle passenger's seat door handle antenna.

4 . The short-distance radio communication system for a vehicle of claim 1 , wherein the portable unit does not respond to the call signal to the in-vehicle unit by shifting the portable unit to a sleep state.

5 . The short-distance radio communication system for a vehicle of claim 2 , wherein the portable unit responds to the call signal to the in-vehicle unit at least (4) if the first received signal strength indicator exceeds the predetermined first threshold and both of the second received signal strength indicator and the third received signal strength indicator do not exceed the predetermined second threshold.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Takigawa Masami
• Hayashi Naoki
• Fujiyama Jun
• Nishimura Toru

Classifications

• H04W4/008 Primary

  Electricity · mapped topic

• H01Q1/32

  Adaptation for use in or on road or rail vehicles · CPC title

• G08C17/02

  using a radio link · CPC title

• B60R25/245

  where the antenna reception area plays a role · CPC title

• H04W4/80 Primary

  Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication · CPC title