In-vehicle communication system, mobile device, communication system, and communication method

Patent metadata

Field	Value
Publication number	US-9430890-B2
Application number	US-201214359769-A
Country	US
Kind code	B2
Filing date	Oct 10, 2012
Priority date	Nov 25, 2011
Publication date	Aug 30, 2016
Grant date	Aug 30, 2016

Abstract

An in-vehicle device stores a Wake Up pattern, which notifies a mobile device of a start of communication, in an area before a data storage area of a frame and transmits the frame, the mobile device includes a modulation/demodulation circuit and a microcomputer that perform a predetermined reception process on a reception signal, a pattern determination circuit that, when the reception signal includes a Wake Up pattern, determines to start communication and activates the modulation/demodulation circuit and the microcomputer, a power detection circuit that detects power of the reception signal, and, when power is detected for a certain period of time or longer, activates the pattern determination circuit, and a Wake-Up control unit that activates the power detection circuit for a predetermined time with a constant period during a time period other than during communication.

First claim

The invention claimed is:

1. A reader of a communication system comprising the reader and a tag that includes a reception processor that performs a reception process on a signal transmitted from the reader and that sets the reception processor to an activated state for a certain period of time with an intermittent operation period T, wherein
the reader transmits a transmission frame, which includes a preamble with a length of T/N (N is an integer equal to or larger than 2) and transmission data with a length shorter than T/N, N times within a time 2T such that transmission times do not overlap with each other.

2. The reader according to claim 1 , wherein the N is variable.

3. A reader of a communication system comprising the reader and a tag that includes a reception processor that performs a reception process on a signal transmitted from the reader and that sets the reception processor to an activated state for a certain period of time with an intermittent operation period T, wherein
the reader transmits a transmission frame, which includes a preamble with a length of T/N (N is an integer equal to or larger than 2) and transmission data with a length equal to or longer than T/N, N times within a certain period of time such that transmission times do not overlap with each other.

4. The reader according to claim 3 , wherein the N is variable.

Assignees

• Ochiai Mari
• Taira Akinori
• Mitsubishi Electric Corp

Inventors

• Ochiai Mari
• Taira Akinori

Classifications

• H04W76/048

  Electricity · mapped topic

• G07C2009/0038

  whereby the wake-up circuit is situated in the keyless data carrier · CPC title

• H04W52/0283

  with sequential power up or power down of successive circuit blocks, e.g. switching on the local oscillator before RF or mixer stages · CPC title

• G07C2009/00365

  in combination with a wake-up circuit · CPC title

• Y02B60/50

  Cross-Sectional Technologies · mapped topic