EP2359493A1

EP2359493A1 - Communication system for automobile

Info

Publication number: EP2359493A1
Application number: EP09756475A
Authority: EP
Inventors: Stephane Violleau
Original assignee: Valeo Securite Habitacle SAS
Current assignee: Valeo Comfort and Driving Assistance SAS
Priority date: 2008-11-21
Filing date: 2009-11-18
Publication date: 2011-08-24
Also published as: FR2938991B1; CN102232273A; US20110223863A1; JP2012509630A; FR2938991A1; WO2010057902A1

Abstract

The invention relates to a communication system for an automobile, that comprises: a receiver (R) housed in the automobile (1), said receiver (R) having at least two reception channels (C1, C2), each channel (C1, C2) being capable of receiving a piece of information transmitted at a predetermined radio frequency (f1, f2); at least one transmitter (E1, E2) capable of transmitting at least a piece of information. According to the invention, the transmitter is capable of transmitting said information at at least one of the two frequencies (f1, f2) that can be received by said reception channels (C1, C2) of said receiver (R).

Description

COMMUNICATION SYSTEM FOR A MOTOR VEHICLE

The present invention relates to a communication system for a motor vehicle equipped with control and monitoring devices.

Motor vehicles are currently equipped with numerous control and monitoring devices, such as access control and / or hands-free remote control access control, tire pressure monitoring. These devices generally communicate with the vehicle by radio waves, between a portable transmitter or located on the vehicle, and a receiver housed in the vehicle.

In order to avoid, when the emissions of the different devices are simultaneous, that the emissions of the different transmitters do not interfere and cause the non execution of a command or a desired control, it was envisaged to use receivers multichannel.

Nevertheless, with the generalization of applications using radiofrequency communication means that they are automotive or foreign to the automobile, such as mobile telephony or home automation, and because of regulatory constraints limiting the frequency allocation ranges, a device operating close to a vehicle, but not specific to that vehicle, can easily cause interference interfering with the proper functioning of the control and monitoring devices operating for that vehicle. The object of the present invention is therefore to remedy this major drawback by proposing a communication system for a motor vehicle comprising:

a receiver housed in the motor vehicle, said receiver comprising at least two reception channels, each channel being able to receive information transmitted at a determined radio frequency,

a transmitter capable of transmitting at least one piece of information, characterized in that the transmitter is adapted to transmit said information on at least two determined frequencies adapted to be received by said receiving channels of the receiver.

Other characteristics and advantages of the invention will appear on reading the detailed description which follows, and figures in which:

- Figure 1 illustrates a communication system according to the state of the art;

FIG. 2 schematizes the process of exchanging information between a transmitter and a receiver for executing an action on a motor vehicle;

FIGS. 3a to 3c show frequency overlap curves between different transmissions for a communication system according to the state of the art; FIG. 4 illustrates a communication system according to the invention;

FIGS. 5a to 5c show frequency overlap curves between different transmissions for a communication system according to the invention.

FIG. 1 represents a communication system according to the state of the art in which a vehicle 1 is provided with at least one receiver R with at least two reception channels, C1 and C2, able to receive information transmitted to frequencies f1 and f2, respectively by emitters E1 and E2. The principle of the exchange between a transmitter E and a receiver R is shown schematically in FIG. 2. The transmitter E comprises a processing unit UT for generating the information to be transmitted. This processing unit UT is connected to a radiofrequency transmission stage EE which emits, via a transmission antenna AE, the information generated by the processing unit UT at the frequency f.

The receiver R has meanwhile a reception antenna AR and a reception unit UR to which the information received by the antenna AR are transmitted via an FPB bandpass filter centered on the transmission frequency f, thus defining a reception channel C.

The information at the output of this reception unit UR is sent to a controller CTRL which analyzes this information and controls the various functions of the vehicle associated with the information received.

In the example illustrated in FIG. 1, E1 is the emitter of a vehicle access remote control 2 and E2 is the emitter of a hands-free access and / or start-up badge 3 of the same vehicle 1.

The operation of an access remote control 2 and a hands-free badge 3 as well as their mode of exchanging information with the motor vehicle 1 are elements well known to those skilled in the art and will not be the same. The object of a detailed description apart from the elements necessary for the understanding of the present invention.

Also shown in Figure 1, near the vehicle 1, an automatic garage door 4, activated by a remote control 5 provided with an emitter E3 emitting at the frequency f3.

To better understand the rest of the description, it is specified that an emission spectrum centered on the frequency f and of width L, and an emission spectrum centered on the frequency f and of width L ', overlap at least partially if :

• in the case where f <f, we have: f - L72 <f + L / 2;

• in the case where f> f, we have: f + L72> f - L / 2;

• f = f

FIGS. 3a to 3c show schematically the emission spectra of the different emitters E1, E2 and E3.

The emission spectra of the emitters E1, E2 and E3 are respectively centered on f1 and L1 wide, centered on f2 and L2 wide, and centered f3 and L3 wide.

More precisely, FIG. 3a shows the emission spectra of the emitters E1 and E2 for the information transmitted at the frequencies f1 and f2 and received by the receiver R respectively on the channels C1 and C2. In accordance with the configuration of a prior art multi-channel receiver communication system, the emission spectra of transmitters E1 and E2 do not have a significant frequency overlap, i.e. C1 and C2 channels have been chosen sufficiently spaced in frequency so that, in the event of simultaneous transmission of the emitters E1 and E2, the information transmitted by each of the emitters is received by the receiver R on the respective channels C1 and C2 without disturbance, and that way each desired command can be executed.

When the remote control 5 of the garage door control device 4 is activated near the vehicle 1, control information is transmitted by the transmitter E3 at the frequency f3. If the emissions of E1 and E3 are simultaneous, as shown in Figure 3b, the respective spectrums overlap at least partially, and that finally the power levels of the emissions are of the same order of magnitude, the command transmitted by the transmitter E1 may not be executed, and the vehicle may not be locked or unlocked by the remote control 2 access system.

In the case where the emission spectrum of E3 at the frequency f3 overlaps with that of E2 at the frequency f2, the emissions are simultaneous, and the power levels of the emissions are of the same order of magnitude, the command transmitted by the Transmitter E2 may not be executed, and the vehicle may not be locked or unlocked, or start may not occur using the hands-free badge system 3.

FIG. 3c illustrates an even more critical situation, for which the emission spectrum of E3 at frequency f3 covers both that of E1 at frequency f1 and that of E2 at frequency f2, and where, therefore, when the remote control 5 of the garage door control device 4 is activated close to the vehicle, none of the access or starting devices 2 or 3, can function properly to the extent that the power levels of the emissions are of the same order of magnitude .

By way of illustration we have considered for a device according to the state of the art the following values: For the access remote control 2, the transmitter E1 has an information transmission spectrum which is centered on a frequency f1 of 433.6 MHz and of width 200 kHz; the information is, in a known manner, control information for locking or unlocking the doors (doors, trunk, tailgate ...);

For the hands-free badge 3, the emitter E2 has an information transmission spectrum which is centered on a frequency f2 of 434.2 MHz and of width 200 kHz; the information is, in known manner, response information to a request for authentication of the vehicle;

And for the garage door remote control 4, the transmitter E3 has an information transmission spectrum which is centered on a frequency f3 of 433.90 MHz and width 500 kHz; the information is, in known manner, a triggering information garage doors.

At the level of the receiver R, the channel C1 is able to receive the transmissions centered on a frequency of 433.6 MHz and of width 200 kHz and the channel C2 is able to receive the emissions centered on a frequency of 434.2 MHz and of 200 kHz width.

These values are therefore representative of the most critical situation, that is, in the case of simultaneous emissions of E1, E2 and E3, the emission spectra will at least partially overlap and the orders transmitted by 2 and 3 can not be executed. Figure 4 now illustrates the communication system according to the invention. The vehicle 1 is always provided with a receiver R with two reception channels C1 and C2 intended to receive information transmitted respectively at frequencies f1 and f2. Unlike the state of the art, each of the emitters E1 and E2 emits at the two specific frequencies f1 and f2. Transmission by the same transmitter at both frequencies can be simultaneous or sequential. On the other hand, and as illustrated in FIGS. 5a to 5c, the frequency spacing between the channel C1 and C2 is chosen so that the transmissions of the emitter E3 at the frequency f3 can not both cover the emissions of the transmitter E1 (E2) at the frequency f1 and the emissions of the transmitter E1 (E2) at the frequency f2.

As shown in FIG. 5b, in the case of simultaneous transmissions of the emitters E1 and E3, and when the transmissions of the emitter E3 at the frequency f3 cover the transmissions of the emitter E1 at the frequency f2, the information transmitted by the emitter E1 at the frequency f1 will be received without interference by the receiver R on the channel C1. This produces the desired command transmitted by the access remote control 2.

In the same way and as illustrated in FIG. 5c, in the case of simultaneous transmissions of the emitters E2 and E3, the transmissions of the emitter E3 at the frequency f3 cover the transmissions of the emitter E2 at the frequency f2, but the information transmitted by the transmitter E2 at the frequency f1, will itself be received without interference by the receiver R on the channel C1. Thus, the desired control, transmitted by the hands-free badge 3, is obtained. For illustration, we have considered for a device according to the invention the following values:

For the access remote control 2, the emitter E1 has a first transmission spectrum centered on a frequency f1 of 433.4 MHz and a width of 200 kHz and a second emission spectrum centered on a frequency f2 of 434, 1 MHz and 200 kHz wide; for each of the two emission spectra, the information is the same, namely control information for locking / unlocking the doors (doors, trunk, tailgate ...); For the hands-free badge 3, the emitter E2 has a first emission spectrum centered on a frequency f1 of 433.4 MHz and a width of 200 kHz and a second emission spectrum centered on a frequency f2 of 434.1 MHz and width 200 kHz; for each of the two emission spectra, the information is the same, namely a response information to a request of the vehicle; "And for the garage door remote control 4, the transmitter

E3 has an emission spectrum centered on a frequency f3 of 433.9 MHz and width 250 kHz.

At the level of the receiver R, the channel C1 is able to receive the transmissions centered on the frequency f1 of 433.4 MHz and of width 200 kHz and the channel C2 is able to receive the emissions centered on the frequency f2 of

434.1 MHz and 200 kHz wide. The spacing of the channels is therefore

500 kHz.

These values are therefore representative of a situation in which in case of simultaneous transmissions of E1 or E2 with E3, the channel C2 will be the seat of a collision between the different information transmitted at the frequency f2 and f3, and no command can be correctly interpreted. The C1 channel meanwhile will remain available on receipt and analysis of the information transmitted by E1 or E2 at the frequency f1.

In another embodiment not shown but with values identical to those previously presented, the hands-free badge

3, which also has a receiver capable of receiving information transmitted by the vehicle, when the badge is in the vicinity of the vehicle, will be informed, in addition to the request, that the channel C2 of the receiver R is currently cluttered. Following this request, the hands-free badge 3 will respond with a transmission at the frequency f1 able to be received by the channel

C1 available. This allows among other things to reduce the energy consumption of the badge hands-free. Indeed each emission produced by the electronic badge is energy consuming, so reducing the number of emissions to one emission, instead of two, reduces the energy consumption of the badge.

Moreover, it has surprisingly been found that in order to obtain the effects expected by the subject of the invention, it was necessary to configuring the communication system such that the reception channels C1 and C2 have a spacing of at least 300 kHz.

The examples that we have just described to illustrate our invention are not limiting. The communication system for a motor vehicle may also include other devices provided with radio transmitters specific to the vehicle such as a tire pressure monitoring device. This device is characterized in particular by the presence on each tire of a radiofrequency transmitter which transmits including information indicative of the relative pressure of the tire.

Claims

1) A communication system for a motor vehicle comprising:

a receiver (R) housed in the motor vehicle (1), said receiver (R) comprising at least two reception channels (C1,

C2), each channel (C1, C2) being able to receive information transmitted at a given radio frequency (f1, f2),

at least one transmitter (E1, E2) capable of transmitting at least one piece of information, characterized in that the transmitter is able to transmit said information on at least two distinct frequencies (f1, f2) able to be received by said channels of reception (C1, C2) of the receiver (R).

2) Communication system according to claim 1, characterized in that the transmitter (E1, E2) emits the two emission frequencies (f1, f2) simultaneously.

3) Communication system according to claim 1, characterized in that the transmitter (E1, E2) emits the two emission frequencies (f1, f2) sequentially.

4) Communication system according to one of claims 1 to 3, characterized in that the transmitter (E1, E2) is a remote control transmitter (2) for access to the vehicle.

5) Communication system according to one of claims 1 to 3, characterized in that the transmitter (E1, E2) is a transmitter of tire pressure monitoring systems of the vehicle. 6) Communication system according to one of claims 1 to 3, characterized in that the transmitter (E1, E2) is a hands-free badge transmitter (3).

7) A communication system according to claim 6, characterized in that the hands-free badge (9) is provided with a receiver adapted to receive a signal comprising information to indicate to the transmitter (E1, E2) to transmit information at a single frequency among the two frequencies (f1, f2) to which it is capable of transmitting said information. Communication system according to one of the preceding claims, characterized in that the frequency spacing of the channels C1 and C2 is at least 300 kHz.