# US 9,430,890 B2 · In-vehicle communication system, mobile device, communication system, and communication method

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- Number: US 9,430,890 B2
- Document ID: US9430890B2
- Status: Granted
- Kind: B2
- Application number: 14/359,769
- Filed: 2012-10-10
- Published: 2014-10-09
- Granted: 2016-08-30
- Earliest claimed: 2012-10-10
- Assignees: Mitsubishi Electric Corporation
- Applicants: Mari Ochiai; Akinori Taira
- Inventors: Mari Ochiai; Akinori Taira
- Web page: https://patentgrep.com/patent/US9430890B2

## CPC

- G07C 9/00182: {operated with unidirectional data transmission between data carrier and locks}
- B60R 25/24: using electronic identifiers containing a code not memorised by the user
- B60R 25/406: {Power supply in the remote key}
- G07C 9/00: Individual registration on entry or exit
- G07C 9/00309: {operated with bidirectional data transmission between data carrier and locks}
- H04W 52/0283: {with sequential power up or power down of successive circuit blocks, e.g. switching on the local oscillator before RF or mixer stages}
- G07C 2009/00365: {in combination with a wake-up circuit}
- G07C 2009/0038: {whereby the wake-up circuit is situated in the keyless data carrier}
- H04W 52/0229: {where the received signal is a wanted signal}
- H04W 76/28: Discontinuous transmission [DTX]; Discontinuous reception [DRX]
- Y02D 30/70: in wireless communication networks
- G07C: TIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE
- B60R: VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE

## 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.

## Claims

### Claim 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.

### Claim 2 (depends on 1)

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

### Claim 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.

### Claim 4 (depends on 3)

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