FR3119284A1 - Method and device for near field data transfer. - Google Patents

Abstract

Title: Method and device for near field data transfer. The invention relates to a method and a device for transferring data from a mobile terminal (TM_E) equipped with a near-field communication module (NFC'). The mobile terminal is capable of positioning itself in an NFC mode (M_NFC ) or in an IBC mode (M_IBC) to perform contactless transactions. The method is characterized in that it comprises, on the mobile terminal (TM_E), the following steps:- selecting (E50) the NFC mode or the IBC mode;- positioning (E52) the mobile terminal in NFC reader mode;- transmitting (E55) an invitation message (WUP_IBC) according to an IBC near-field communication type (NFC-IBC); - deactivate (E56) the NFC reader mode; - receive (E57) a pairing message (ACK_IBC) on a return channel (CR) separate from the near field channel; - transfer (E58) the data on the return channel (CR). fig. 8

Description

Method and device for near field data transfer.

Field of the invention

The invention relates generally to telecommunications, and more specifically to contactless communications using short-range radio technologies, in particular of the NFC (Near Field Communication) type. It applies more particularly to terminals equipped with physical and software resources including a microprocessor and a near field communication module (Near Field – NF) receiving an electromagnetic field.

Prior Art

Near-field communications, usually called NFC, based mainly on the ISO (International Standard Organization) 14443 standard and on the ISO/IEC 18092 standard, use wireless technologies to allow an exchange of information between two peripherals far from each other. a short distance, typically less than ten centimeters. Communications of this type offer many applications in the fields of payment or transport, for example.

Recently in this field, new wireless communication techniques have appeared using the human body as a channel. In these technologies, which are grouped under the generic term of IBC (from English: Intra-Body Communication ) or even BCC (for Body Channel Communication ), the human body also acts as a conductor to transmit information from one point to another. It is therefore no longer necessary to approach the IBC terminal to its counterpart to establish communication: it can be kept in the pocket, in a bag, etc. of the wearer. By approaching the hand of an NFC reader terminal, the individual wearing the IBC terminal establishes secure communication between his terminal and the reader terminal. Document WO2017/093639 describes such a system, for example.

But the wearer may be required to carry out IBC communications between his mobile terminal and another mobile terminal, in particular to transfer data. This is not possible today.

There is therefore a need to ensure communication between two mobile terminals equipped with an IBC functionality.

The invention improves the state of the art.

To this end, it proposes a method for transferring data from a mobile terminal equipped with a near-field communication module, said mobile terminal being capable of positioning itself in an NFC mode or in an IBC mode to carry out contactless transactions.
the method being characterized in that it comprises, on the mobile terminal, the following steps:
- select NFC mode or IBC mode;
- position the mobile terminal in NFC reader mode;
- send an invitation message according to a type of near-field communication IBC;
- disable NFC reader mode;
- receive a pairing message on a return channel separate from the near-field channel;
- transfer the data on the return channel.

Advantageously according to the invention, a specific protocol is set up between the transmitting mobile terminal and another mobile terminal, receiver, operating in IBC mode. The transmitting mobile terminal can be positioned in NFC mode or in IBC mode. In IBC mode, he keeps his terminal close to his body, which carries the near-field signal. To establish communication, his body must be brought closer to that of the wearer of the receiving terminal. In NFC mode, he keeps his terminal in his hand. To establish communication, its terminal must be brought closer to the body of the wearer of the receiving terminal. In both cases, it sends an invitation message in IBC format, and opens the call on a separate return channel, upon receipt of the return message from the destination IBC terminal. It is positioned in NFC reader mode for a limited time at the start of the IBC transaction. Indeed, the NFC reader mode consumes a lot of energy, so it is advisable to deactivate it as soon as the pre-pairing is finished, either just after sending the invitation message, or after receiving the pairing request.

Advantageously, it is thus possible to transfer data which may be voluminous between, on the one hand, a transmitting terminal positioned in NFC or IBC mode and, on the other hand, a receiving terminal positioned in IBC mode, i.e. say it is in the pocket, bag, etc. of the user of the receiving terminal.

By “mobile terminal” is meant here a mobile terminal equipped with an NFC module. It can be, for example, a mobile phone, or smartphone, or even a connected object. The transmitting mobile terminal can be positioned in NFC mode or in IBC mode. By " IBC " or IBC mode, we mean near-field communication passing through the body of the user. The term is used as opposed to the " NFC " mode which corresponds to the standard mode of an NFC communication, in which the terminal which includes the NFC device (classically, a mobile terminal, or smartphone) is in physical proximity to its vis-à-vis. -NFC screws.

By “near-field communication module” is meant a controller, or NFC component (CLF for ContactLess Frontend ) constituting a near-field communication module like an electromagnetic transponder and comprising software components (firmware, etc.) necessary for the implementation of NFC communications. Such a component is associated with an antenna, which transmits the NF signals received to the NFC component.

By “type of near-field communication” is meant a communication of the standard NFC type, or of the IBC type, that is to say a communication established in the near field according to the standard NFC type or according to the IBC type intended for the transmission of electromagnetic waves through the user's body.

“Reader mode” means a terminal equipped with an NFC module capable of positioning itself in NFC reader mode as defined by the NFC standards. In reader mode, the terminal uses its own RF field to communicate. It is said to be active. On the contrary, in card emulation mode, the terminal responds to a command from the initiator/reader in a passive mode using load modulation.

According to a particular embodiment of the invention, the method as described above further comprises, after the step of positioning the mobile terminal in NFC reader mode:
- a step of arming a reader mode timer;
- a reader mode deactivation step if the timeout is exceeded.

Advantageously according to this mode, the method arms a reader mode timeout. Such a delay, corresponding to the maximum duration of time during which the mobile terminal can remain in reader mode, makes it possible to prevent the mobile terminal from remaining too long and unnecessarily in this mode which consumes a lot of energy, which would exhaust its batteries. .

According to another particular embodiment of the invention, which may be implemented cumulatively or alternatively with the previous ones, the method as described above is further characterized in that the IBC or NFC mode is selected via a man-machine interface of the mobile terminal.

Advantageously according to this mode, the terminal can be positioned by default, or temporarily, in one mode or the other. It is particularly interesting to position it in IBC mode by default, because the user who has the IBC mode may no longer wish to use the standard NFC mode, since the IBC allows him to keep his terminal in his pocket. A default positioning can be ensured for example via the configuration parameters of the terminal. The user can leave this default mode by reactivating the other mode (via a menu, a push button, a slider , etc.) The terminal can also be positioned by the user in one or the other mode of temporarily: for a certain duration, or for a set of transactions, or for a single transaction.

According to another particular mode of implementation of the invention, which may be implemented cumulatively or alternatively with the previous ones, the method as described above is further characterized in that a type of IBC application is selected via a man-machine interface of the mobile terminal.

Advantageously according to this mode, an IBC application, for example data transfer via IBC, can be positioned by default, or temporarily, by the user. An application can be selected for example via the configuration parameters of the terminal (via a menu, a push button, a slider , etc.), or an on-screen menu, etc. The selection of such an application, or option, makes it possible to launch the appropriate program, for example for transferring content, when such content (a video, a Web site, an address book, etc.) is selected at the screen by the user.

According to another particular embodiment of the invention, which may be implemented cumulatively or alternatively with the previous ones, the method is characterized in that said invitation message contains one or more data from among:
- a hazard to establish the return channel;
- a type of IBC application;
- a type of return channel;
- a service parameter.

Advantageously according to this mode, the hazard, or random data, can be used to reinforce security when establishing the return channel: if the same hazard is shared by the transmitting mobile terminal and the receiving mobile terminal, the communication can be placed securely on the return channel. The hazard, also called "challenge" takes the form of a parameter allowing a blase calculation of secret cryptographic keys, the result of which is compared by the two entities before establishing the communication.

Advantageously according to this mode, the type of IBC application (for example IBC-S) can also be transported in the invitation message. This makes it possible to define a number of different transactions for the IBC (transport, payment, game, data transfer, etc.) and to verify at the receiver level that the type of application is indeed the one it expects. The existing NFC standard can be reused by using for example a reserved field, or a field already defined for proprietary applications, which therefore does not disturb the operation of a receiver which would only be of the NFC type, and makes it possible to easily add IBC mode and its different applications.

Advantageously, according to this mode, the return channel can also be specified (Wi-Fi, Bluetooth, cellular channel 4G, 5G, etc.). This notably allows the transmitter to know on which channel he must listen to the response, and the receiver to know on which channel he must request pairing.

The invention also relates to a device for transferring data from a mobile terminal equipped with a near-field communication module, said device being capable of positioning the mobile terminal in an NFC mode or in an IBC mode to carry out transactions without contact, characterized in that it is configured to implement at the level of the mobile terminal:
- select NFC mode or IBC mode;
- position the mobile terminal in NFC reader mode;
- send an invitation message according to a type of near-field communication IBC;
- disable NFC reader mode;
- receive a pairing message on a return channel separate from the near-field channel;
- transfer the data on the return channel.

The invention also relates to a transmitting mobile terminal comprising such a data transfer device.

The invention also relates to a method for receiving data on a mobile terminal equipped with a near-field communication module, said mobile terminal being capable of positioning itself in an IBC mode to carry out contactless transactions, the method being characterized in what it includes on the mobile terminal the following steps:
- position the mobile terminal in IBC mode;
- receive an invitation message according to a type of near-field communication IBC;
- send a pairing message on a return channel separate from the near-field channel;
- receive data on the reverse channel.

Advantageously according to the invention, the receiving terminal, positioned in IBC mode, receives the data transfer invitation message from the transmitting terminal. If it is correctly positioned in IBC mode, and authorizes the data transfer application, it responds on the return channel and receives the data on this channel, once communication is established.

According to a particular embodiment of the invention, the reception method as described above is further characterized in that the IBC mode is selected via a man-machine interface of the mobile terminal.

Advantageously according to this mode, the receiving terminal can be positioned in the IBC mode by default, or for a certain duration, or for a set of transactions, or for a single transaction, by the user, as described for the transmitting terminal.

According to a particular embodiment of the invention, the reception method as described above is further characterized in that an IBC application type is selected via a man-machine interface of the mobile terminal and/ or received in the invitation message.

Thus, the user may have selected the type of IBC-S application to authorize this application on the receiving mobile terminal and/or read it in the invitation message.

According to a particular embodiment of the invention, the reception method as described above is further characterized in that the type of return channel is received in the invitation message.

Advantageously, the return channel is specified in the invitation message, which allows the receiving terminal to know on which channel (for example Bluetooth) to request pairing.

The invention also relates to a device for receiving data from a mobile terminal equipped with a near-field communication module, said device being able to position the mobile terminal in an IBC mode to carry out contactless transactions, characterized in that that it is configured to implement at the mobile terminal level:
- position the mobile terminal in IBC mode;
- receive an invitation message according to a type of near-field communication IBC;
- send a pairing message on a return channel separate from the near-field channel;
- receive data on the return channel.

The invention also relates to a receiver terminal comprising such a reception device.

The invention also relates to a system comprising a transmitting mobile terminal equipped with a transfer device as described previously and a receiving mobile terminal equipped with a receiving device as described previously, characterized in that the transfer of data is triggered when the transmitting mobile terminal positioned in NFC mode comes close to the body of the user of the receiving mobile terminal.

The invention also relates to a system comprising a transmitting mobile terminal equipped with a transfer device as described previously and a receiving mobile terminal equipped with a receiving device as described previously, characterized in that the transfer of data is triggered when the body of the user of the transmitting mobile terminal positioned in IBC mode comes into proximity to the body of the user of the receiving mobile terminal

The invention also relates to computer programs comprising instructions for the implementation of one of the above methods according to any one of the particular embodiments described, when said program is executed by a processor. The method can be implemented in various ways, in particular in wired form or in software form. This program may use any programming language, and be in the form of source code, object code, or intermediate code between source code and object code, such as in partially compiled form, or in any other desirable form.

The invention also relates to a recording medium or information medium readable by a computer, and comprising instructions of a computer program as mentioned above. The recording media mentioned above can be any entity or device capable of storing the program. For example, the medium may comprise a storage means, such as a ROM, for example a CD-ROM or a microelectronic circuit ROM, or else a magnetic recording means, for example a hard disk. On the other hand, the recording media may correspond to a transmissible medium such as an electrical or optical signal, which may be conveyed via an electrical or optical cable, by radio or by other means. The programs according to the invention can in particular be downloaded from an Internet-type network.

Alternatively, the recording media may correspond to an integrated circuit in which the program is incorporated, the circuit being adapted to execute or to be used in the execution of the method in question.

List of Figures

Other characteristics and advantages of the invention will appear more clearly on reading the following description of particular embodiments, given by way of simple illustrative and non-limiting examples, and the appended drawings, among which:

There illustrates the context of the invention according to an IBC mode and an NFC mode.

There illustrates an architecture of an IBC/NFC mobile terminal according to a particular embodiment of the invention.

There illustrates an architecture of a reader terminal, or IBC/NFC terminal, according to a particular embodiment of the invention.

There illustrates initialization steps of the IBC/NFC communication method according to one embodiment of the invention.

There illustrates the IBC/NFC communication initialization frame according to a particular embodiment of the invention.

There illustrates a transfer of data between two IBC mobile terminals according to one embodiment.

There illustrates a transfer of data between two IBC mobile terminals according to another embodiment.

There illustrates the steps of a data transfer method between two IBC mobile terminals according to one embodiment.

Description of an embodiment of the invention

General principle of the invention

The general principle of the invention consists in using a specific protocol between the reader terminal and the IBC/NFC mobile terminal to initialize a communication according to one mode or the other, in the case of a mobile terminal which is capable of operate in both modes, which is the case with most mobile phones, or smartphones, on the market. In particular, by receiving an IBC type communication request, the mobile terminal will establish the software and hardware actions necessary to allow the transaction by the body, while by receiving an NFC communication request, it will establish standard NFC communication, according to the 'state of the art. To this end :

1. the mobile terminal is positioned in NFC or IBC mode. It may command the NFC-IBC component of the mobile so that it is positioned in the correct mode; Indeed, the reception of an IBC message can take place in an NFC hardware mode, but the message will be of poor quality if no adaptation has been made. Then it carries out a “pooling”, that is to say that it listens until it receives an appropriate message. If it is in one of the two modes and receives an initialization message in this mode, it launches the transaction. On the other hand, if it is in one of the two modes and receives the initialization message in the other mode, it remains awaiting an appropriate message.
2. The reader terminal, which does not a priori know how to distinguish an NFC transaction from an IBC transaction, sends NFC and IBC messages periodically, thereby respecting the "polling" protocol defined by the NFC standards. Depending on the response it receives, it deduces one of the two modes, and can initiate the transaction. In particular, if he receives an NFC response, he knows that he is dealing with an NFC mobile terminal, if he receives a message on another radio channel, in particular a pairing request, he knows that he has dealing with an IBC mobile terminal. This return channel can be Bluetooth, Wi-Fi, Li-Fi, 4G or 5G cellular, etc. as long as it is a "short" distance transmission channel, for example less than 10 meters, different from the near field channel.

Particular embodiments of the invention.

There illustrates the context of the invention, respectively in IBC and NFC modes.

In both modes, the user (2) carrying the mobile terminal equipped with an NFC-IBC module approaches until almost touching the reader terminal TP to implement a service, for example a monetary transaction. The TP and TM terminals are able to communicate directly in the near field (NFC) or via an electromagnetic field (NF) using the user's body (IBC).

The reader terminal TP can be for example a TPE (for Electronic Payment Terminal), or even a mobile terminal having an NFC module positioned in reader mode, a connected object (in English, IOT), a personal computer, a computer mouse computer, a home gateway, etc. It is capable of transmitting NFC type radio signals via an NFC antenna. In this example, the reader terminal (TP) comprises a surface constituted by the optionally protected antenna and adapted to react when the user touches it or comes into proximity with it in IBC mode, for example by approaching the hand, or when he approaches his mobile in NFC mode. The term "surface" is in no way limiting and given for illustrative purposes, the antenna being the only means essential to the operation of the device.

The mobile terminal TM is according to this example a mobile terminal equipped with an NFC-IBC module. By NFC-IBC module we mean a near-field reception module, capable of receiving an electromagnetic wave either directly (NFC mode) or after it has passed through the user's body (IBC mode). A conventional NFC component is capable of receiving IBC signals with degraded quality, but there are also techniques for improving the quality of the signal received in IBC mode by software and/or hardware adaptation of the NFC component and its antenna. It is also capable of establishing a bidirectional return channel (for example Bluetooth) with the reader terminal. According to another example, this mobile terminal TM could be a computer, a connected object, a tablet, etc.

In the IBC mode shown on the left of the , denoted M_IBC, the IBC module behaves like a portable device naturally capable of receiving radio carrier waves, via an antenna, through the body of the user (2). To this end, the mobile terminal is located in the immediate vicinity of the user (2), without necessarily being in direct contact with the latter. For example, the mobile terminal is placed inside a user's pocket. It could also be placed in a bag, or around his neck, etc. In these configurations, it is estimated that the mobile terminal is not more than a few centimeters away from the body of the user (2). The distance is for example less than 5 cm. When the user performs a movement towards the reader terminal, typically by touching or brushing with the hand the receiving surface comprising the NFC antenna of the reader terminal, a radio carrier wave is transmitted from the reader terminal through the body of the user. . Two phases are linked on the mobile terminal in a transparent way for the user, in order to provide the service. First of all, a contactless phase of the IBC type, which can be considered as a pre-pairing, is initiated. The mobile terminal receives an IBC type message, and if the message is correct, pairs up, or pairs up, on the return channel with the reader terminal to allow two-way communication between the two terminals. Indeed, it is not possible to transmit a voluminous response message via the body of the user from a mobile terminal. Such a dialogue, consisting of a pairing phase followed by the establishment of a two-way communication using a Bluetooth link, is described in the document WO2017/093639, included here by reference.

In the “classic” NFC mode shown in , on the right (M_NFC), the bearer performs the transaction by physically approaching the mobile terminal to the reader terminal. Communication is naturally two-way on the NFC channel, but the volume of data exchanged remains very limited.

The use of either mode must be transparent for the user, i.e. he must be able to carry out the transaction with the reader terminal either in IBC mode while keeping the mobile in his pocket, or in NFC mode by taking the mobile terminal out of its pocket and bringing it closer to the reader terminal, without intervening on his mobile terminal. The embodiments described in more detail below allow this transparency, and automation of the process.

There illustrates an architecture of the mobile terminal TM according to a particular embodiment of the invention.

The mobile terminal TM has the classic architecture of a mobile telephone, of the smartphone type, and notably comprises a memory MEM, a processing unit equipped for example with a processor PROC, and controlled by the computer program PGR stored in MEM memory. On initialization, the code instructions of the computer program PGR are for example loaded into a memory before being executed by the processor PROC. The processor PROC of the processing unit UT notably implements the steps of the adaptation method according to any one of the particular embodiments described in more detail below, according to the instructions of the computer program PGR.

The mobile terminal also includes the following modules:

• an NFC module for managing NFC and IBC communications. This module conventionally comprises a contactless communication integrated circuit (CLF: Contactless Front-End) associated with an ANT antenna initially provided for receiving NFC signals; the circuit formed by the CLF and the antenna can be adapted to receive IBC signals with better quality via the human body.
• a DNF module for managing IBC/NFC near field communications. This module is in particular in charge of the IBC or NFC mode selection steps, either directly (for example from the user via an HMI of the mobile terminal) or by a so-called "pooling" mechanism, which consists for the mobile terminal positioning itself in a mode (for example IBC) then listening on the near-field communication channel, and validating this mode if a message received corresponds to the selected mode.
• a PIBC module for the specific management of IBC communications. This module notably executes the steps necessary for decoding the IBC initialization message and establishing the return channel to carry out the transaction in IBC mode. Optionally, it is also able to control the adaptation of the NFC circuit (CLF component and its antenna) to improve IBC reception.
• a PNFC module for managing NFC communications. This module notably executes the steps classically necessary for establishing and executing the NFC transaction. It places the mobile terminal in card emulation mode or in reader mode, depending on the prerequisites of the targeted application.
• a communication module distinct from the NFC module, for example Bluetooth (or Wi-Fi, Li-Fi, etc.) denoted CR in the figure, to ensure the return channel, and therefore the bidirectionality of the IBC communication. The CR module is connected to an antenna, either directly or via the mobile phone:

• in the first case, the module CR is for example associated with the NFC component, possibly on the same substrate. For example, it is connected to the output of the antenna demodulator, possibly through other circuits. It receives the demodulated data and possibly processed by a microprocessor, and is responsible for establishing a Bluetooth communication channel.
• in the second case, the module CR is located elsewhere, for example in the mobile terminal. The demodulated antenna signals are transmitted to the microprocessor of the mobile terminal which is responsible for establishing the return channel (Bluetooth, Wi-Fi, cellular radio, etc.). Advantageously in this case, the corresponding module present natively on the mobile terminal can be reused.

• an HMI user interface, suitable for transmitting instructions or information messages to the user and receiving information from him. For example, the user interface is the screen of the smartphone. In another exemplary embodiment, the interface is an audio interface making it possible to receive messages and instructions. The HMI can also include a keyboard, a microphone, etc. For example, it can be arranged to enter the preferred mode (IBC or NFC) of the user, temporarily, for a transaction or a set of transactions.

There illustrates an architecture of a reader terminal, or IBC/NFC terminal, according to a particular embodiment of the invention;

The reader terminal TP has the classic architecture of a computer, and notably comprises a memory MEM', a processing unit equipped for example with a processor PROC', and controlled by the computer program PGR' stored in memory MEM '. On initialization, the code instructions of the computer program PGR' are for example loaded into a memory before being executed by the processor PROC'. The processor PROC' of the processing unit UT' notably implements the steps of the adaptation method according to any one of the particular embodiments described, according to the instructions of the computer program PGR'.

The reader terminal also includes:

• an NFC’ module for the management of near field communications, NFC or IBC. This module conventionally comprises a contactless communication integrated circuit (CLF: Contactless Front-End) and an ANT antenna provided for transmitting and receiving NFC signals.
• a DNF’ module for managing IBC/NFC near field communications. This module is in particular in charge of the IBC or NFC mode selection steps by means of a so-called "pooling" mechanism, which means here that the reader terminal periodically transmits messages of a certain type (NFC or IBC) and listens to the response on a return channel. If it has sent an IBC frame and receives a response on the return channel (Bluetooth), it can initiate IBC communication. Otherwise, if he has sent an NFC frame, and receives a response on the NFC channel, he typically has to check the NFC message (the type of card emulated, etc.) according to a well-known pooling mechanism of the state art and described in the "NFC Activity Technical Specification" of the NFC forum (NFC Forum-TS-Activity-1.0 2010-11-18)
• a PIBC’ module for managing IBC communications. This module performs in particular the steps necessary for the establishment of the IBC prompt message which will be detailed in support of Figure 5, the insertion of this message in the polling mechanism, in cooperation with the module PNFC ', and the establishment of the return channel with the mobile terminal, to carry out the transaction in IBC mode.
• a PNFC' module for managing NFC communications. This module notably executes the steps conventionally necessary for the NFC transaction according to the state of the art constituted in particular by the NFC 14443 standard and the technical specification mentioned above. The main steps for initializing NFC communication between a transmitter and the card are described in part 3 of the standard ( ISO 14443-3 - Identification cards — Contactless integrated circuit(s) cards — Cards proximity — Part 3: Initialization and collision avoidance ). It also positions the reader terminal in NFC reader mode.
• a module CR' intended to transmit and receive data on the return channel. The module is in particular arranged to implement the steps of reception/transmission of messages relating to the transaction on the return channel.
• optionally, an HMI user interface, suitable for transmitting instructions or information messages to the user. For example, the user interface is a screen on which messages and instructions are displayed. In another exemplary embodiment, the interface is an audio interface making it possible to play the messages and instructions. The HMI can also include a keyboard, a microphone, etc. For example, it can be arranged to implement an invitation step of the communication process.

It will be noted that any reader terminal on the market can advantageously be used, provided that it benefits from the PIBC' modules allowing it, by a simple update of the software of the reader terminal, to make it capable of transmitting a message having the characteristics of the IBC invitation message according to the invention, and to insert it into the polling mechanism, via its NFC antenna.

It will also be noted that the reader terminal TP can be a transmitting mobile terminal whose architecture is similar to that of the device TP described here. However, a mobile terminal is not suitable for being positioned in reader mode for a long time because this mode drains the batteries. Figures 6 to 8 propose an embodiment which solves this problem.

There illustrates steps of the NFC/IBC adaptation method according to one embodiment of the invention.

According to this embodiment, a mobile terminal TM seeks to validate an electronic transaction according to one of the two contexts presented respectively in , that is to say that the transaction is carried out either in NFC if the user 2 approaches his mobile terminal to the reader terminal (M_NFC), or in IBC if he keeps his mobile terminal in his pocket (M_IBC).

Remember that NFC communications can cover two types of applications related to two different operating modes on an NFC device:

- The first mode, called reader mode, relates to the reading of data on devices of the transponder type, or NFC cards. The device in this mode is active. It transmits commands to a mobile terminal as it would send them to a contactless card according to the ISO 14443 (or Felica) standard. It generates a magnetic field which, in contact with the antenna of the passive card, induces an electric current which powers the card.

- The second mode, called emulation mode, implements emulation of a near-field communication module, typically to secure electronic transactions between an application stored on the device and an external reading terminal, or reader terminal; in this mode, the device's NFC equipment is used passively. It simulates the behavior that a passive contactless card would have.

In addition, NFC devices meeting the ISO 14443 standard communicate using a range of respective distinctive feature technologies. The generic NFC standard is subdivided into three sub-standards NFC-A, NFC-B and NFC-F. These three sub-standards use a 13.56 MHz field. They differ by the way of modulating this field in amplitude, by the coding of the transmitted symbols as well as by the bit rate. An NFC-compatible mobile terminal, such as a mobile telephone, generally supports several, or even all, of the sub-standards. Similarly, a commercial reader terminal generally supports several types of cards.

The NFC standards, in particular the aforementioned NFC Activity Technical Specification, specify a protocol for establishing the technology to be used when more than one technology is available (NFC–A, NFC–B, NFC–F) on the reader terminal. This is called “polling”. The protocol constrains the reader terminal to send a near-field invite message, which requests a response to one of the available sub-standards, starting with NFC-A. The listening mobile device (or card) will only respond if it is able to communicate using NFC–A; the reader terminal reacts in a limited time interval to the absence of response by transmitting a second invitation signal in a second technology, for example NFC-B. This process is repeated until the listening mobile terminal responds with an invitation response signal indicating compatibility with an NFC sub-standard.

The embodiment described here adds a new NFC-IBC substandard to the existing substandards. This new sub-standard integrates with the polling mechanism while maintaining compatibility with existing NFC sub-standards.

Thereafter, we will call “NFC mode” one of the sub-modes defined by the NFC forum, and “IBC mode” the additional sub-mode as set out in the embodiments of the present invention.

We will now describe the in support of the following steps E0 to E25:

During an initialization step E20, the reader terminal positions itself in reader mode and prepares its WUP invitation message (for Wake-UP) for the type of sub-standard targeted (NFC-B, NFC-A, NFC -F or NFC-IBC) with the aim of initiating a dialogue between the reader terminal and the mobile terminal, in NFC or IBC mode, in accordance with NFC standards, enriched according to the invention with a new IBC message integrated into the mechanism of polling.

During an initialization step E0, the mobile terminal TM activates its NFC module and positions itself in card emulation mode. Then he chooses to position himself either in IBC mode (M_IBC) or in NFC mode (M_NFC). Then the mobile terminal TM is approached to the terminal (NFC mode) or the user's hand is approached to the terminal (IBC mode) thereby authorizing the transmission of the carrier wave of the invitation message through his body. In both cases, the mobile terminal receives the electromagnetic field generated by the reader terminal, as explained above.

During a step E21, the reader terminal enters a polling process as described above, that is to say it transmits successively (and cyclically), until obtaining a response, an invitation of the type corresponding to the sub-standards it implements (NFC-A, NFC-B, NFC-F, NFC-IBC, etc.) This invitation is noted in figure WUP_X, where X takes the value A, B, F, IBC . NFC sub-standard messages are specified by the standard and will not be detailed here.

The new IBC initialization message follows the message format of the standard. According to an example, detailed later in support of the , it is an NFC-B type message so the fields are reused to advantage to indicate the new type of communication (IBC) and optionally service data and/or in a non-exhaustive manner a random number intended for the subsequent pairing on the return channel, a type of return channel (CR) to use (BT, Wi-Fi, 5G, etc.), etc. Thus, in the NFC mode, the messages exchanged between the reader terminal and the mobile terminal are not modified. In IBC mode, the new initialization message, when it is received by the mobile terminal, makes it possible to launch the IBC communication procedure: pairing and continuation of the transaction on the return channel (Bluetooth for example).

During a step E1, the mobile terminal TM receives the initialization message, WUP_X with X=IBC or NFC-(A, B, F);

During a step E2, it determines the type of message received (X); if X=NFC, it starts the NFC recognition procedure defined from step E10, otherwise it starts the IBC recognition procedure defined from step E3.

During step E10 (X=NFC, the message received is an NFC invitation), a test can be performed to find out whether the mobile is actually positioned in NFC. If this is not the case, a return to step E0 is performed, otherwise the classic NFC procedure begins with step E11. It should be noted that this step is optional insofar as, if the mobile TM receives an NFC message while it is positioned in IBC mode, it does not matter whether it responds to the NFC message since this response will not be received by the reader terminal . Indeed, such a response signal will be too attenuated by the distance between the mobile terminal, positioned in card emulation mode, and the reader terminal (they are separated in IBC mode by the user's body). Indeed, the mobile terminal operates in load modulation, that is to say by induction. The 14443 standard indicates that, in such a situation, the mobile terminal in emulation and the reader terminal can no longer communicate if they are more than approximately 10 cm apart. Thus the reader terminal cannot receive such a message, and therefore returns to step E20 or E21 at the end of the time defined by the NFC “polling” mechanism.

During steps E11 and E12, a standard NFC type transaction is carried out, with in E11, the mobile terminal sending the NFC acknowledgment if the type of NFC request corresponds to the capacities of the mobile terminal (for example ACK-A for confirm operation in NFC-A mode), then, if the reader terminal validates the communication during step E22, upon receipt of the response message, the conventional execution of the NFC transaction during steps E12 and E23, by example the validation of a contactless payment.

During step E3 (X=IBC, the message received from the reader terminal is an IBC invitation of the WUP-IBC type), a test can be performed to find out whether the mobile is actually positioned in IBC. If this is not the case (it is in NFC mode), a return to step E0 is performed, otherwise the classic IBC procedure begins with step E4. It will be noted that this step E3 is optional insofar as, if the mobile TM receives an IBC message while it is positioned in NFC mode, it cannot respond to this message which does not correspond to an expected format in NFC (defined per standard 14443). Thus the reader terminal does not receive a response and therefore returns to step E20 or E21 at the end of the time defined by the NFC/IBC “polling” mechanism.

If the test is positive in E3 (if X = IBC and the mobile is in IBC mode), step E3 (or step E2 if step E3 is not implemented) is followed by step E4 at during which the mobile terminal decodes the message (hazard, type of service, etc.), then initializes the return channel: it possibly activates the channel (for example by opening Bluetooth or Wi-Fi on the terminal if this is not is not already done), requests a pairing from the reader terminal on this channel (BT, etc.) by transmitting for example an IBC transaction confirmation, denoted ACK_IBC on this channel. This ACK_IBC message may in particular include the encrypted random number used to secure the return channel. These steps are described in document WO2017/093639, included here by reference.

Then, if the reader terminal validates the communication during step E24 upon receipt of the response message, in particular because it has received a message on the expected return channel with the expected randomness; the communication continues on this return channel during steps E4 and E24, for the reception/transmission of messages relating to the IBC transaction (to validate a payment, a ticket balance, or exchange any other message required for the communication, etc. .)

There illustrates an IBC initialization message according to one embodiment.

The main steps for initializing NFC communication between a transmitter and a card are defined in part 3 of ISO 14443-3. For a type B card, the reader terminal sends an identification request (called “REQB” or “WUPB”) and waits for a response (called “ATQB”) from the mobile terminal.

The invention proposes to reuse such a protocol message, so as to insert an indication of the "IBC" type and optionally a certain number of data necessary for the subsequent IBC communication (hazard, type of request, type of IBC application, type return channel, etc.).

As shown in , and detailed in the aforementioned standard 14443-3, the standardized REQB/WUPB message contains:

• a start of frame byte, SOF;
• an APf anti-collision prefix byte (of fixed value, in hexadecimal 0x5);
• a byte called “AFI” indicating the application family representing the type of application targeted by the NFC reader (all applications – code 00, transport, finance, telecommunications, etc.) Only proximity cards with applications of the type indicated by the AFI are authorized to respond to a REQB/WUPB command with an AFI other than "00". When AFI is "00", all proximity cards must process REQB/WUPB. These coding rules are specified in table 12 of the aforementioned standard 14443, reproduced below;
• a “param” byte indicating in particular the type of request (REQB or WUPB);
• a "CRC_B" byte on two bytes comprising a code allowing errors to be detected and corrected.

There illustrates a possible reuse of these fields, concerning a particular mode of implementation.

The IBC initialization WUP_IBC message contains, according to the first example (WUP_IBC (1)), the start of frame (SOF) message immediately followed by the data bytes (DATA1, DATA2, DATA3, etc. necessary for the establishment of the IBC request. As the AFI field is overwritten, a card or a type B mobile terminal will not respond to this request. The data fields may include in particular the hazard, IBC service information, the type of IBC application (transport, file transfer, etc.), etc. The message also contains a "CRC_IBC" byte on two bytes containing a code allowing errors to be detected and corrected.

The IBC initialization WUP_IBC message contains, according to the second example (WUP_IBC (2)):

• a first byte of anti-collision prefix APf, unmodified (although the anti-collision algorithm is of little use in the case of the IBC, because it can hardly be several users whose hand is present simultaneously in front of the reader terminal) ;
• the "AFI" byte adapted for the IBC while maintaining compatibility with the standard. With reference to table 12 of the aforementioned standard 14443, reproduced above, the value 0x0 of the first half-byte corresponds to a private subfamily of the type specified in the second half-byte. We can therefore use this second half-byte to specify the type of IBC application, keeping the standardized values (for example '1' for transport, '2' for finance, etc. by analogy with the values from '1' to ' 9' of the first half-byte of the table.)

Naturally, these two examples are in no way limiting and those skilled in the art could imagine any adaptation of this WUPB/REQB message or of another NFC initialization message. For example :

• the hexadecimal values 0x9 to 0xF of the first half-byte of the AFI field are reserved; it is therefore possible without encroaching on the standard to use one of these reserved values, for example 0x9 for IBC applications, in general, the second half-byte of the field comprising the type of IBC application;
• a modification of the value of the SOF field would allow the mobile terminal to immediately detect a non-NFC message
• etc

Figures 6 and 7 illustrate IBC communication according to another embodiment, for data transfer between two mobile terminals.

The receiving mobile terminal TM_R can have the type of architecture presented in . The sender mobile terminal TM_E can have the type of architecture presented in , that is to say that it is capable of behaving like a reader terminal capable of polling invitation messages.

According to this embodiment, the user of the receiving mobile terminal TM_R is positioned in IBC mode. For example, he makes this choice by checking a box in the parameters of his mobile terminal, as shown in the or 7. The user of the TM_E sending terminal can choose to position his terminal in NFC or IBC mode. For example, he makes this choice by checking a box in the terminal settings, as shown in the or 7: the configuration of the mobile terminal authorizes, according to this example, an NFC mode (which is already present on most mobile terminals on the market) or an IBC mode for the connectivity of the mobile terminal to be ticked. According to the example, it is also possible to select a BT (Bluetooth) mode, useful in particular for the IBC return channel. In addition, in IBC mode, a new application is authorized, represented in the figure by “IBC-S” which signifies that the mobile is authorized to use a data transfer application in IBC. This type of service indication can also be proposed for example in the data field, or in the "type" field of the invitation message proposed to the . Naturally, there could be many other IBC services such as gaming services, streaming services, etc.

It should be noted that in IBC mode, optionally, the user does not need to activate the CR module of the return channel (according to the example, Bluetooth - BT) before using his mobile in IBC because the application IBC can take care of it for him, automatically when connecting IBC, then after the data transfer, the return channel can be deactivated.

The two mobile terminals TM_R and TM_E seek to communicate in order to exchange data, in particular voluminous data which could not be transmitted according to near-field technology, the bit rate capacities of which are limited. Indeed, the maximum speed offered by NFC is 424 kb/s, which is not sufficient to allow a transfer of large data. In addition, a transaction of this type carried out using NFC or IBC means that the mobile terminal or the user's hand remains resting on the reader terminal, which is uncomfortable and requires high positioning precision.

According to this example, the user 2' of the terminal TM_E wishes to transmit a video P to the terminal TM_R of the user 2 (alternatively it could be any document such as sound, Web pages, photos, etc.)

In the context of the , the two users are positioned in IBC. They both activated the IBC option and the IBC-S application on the TM_R and TM_E terminals. When user 2' touches user 2 (or vice versa, regardless of the moment they come into proximity in the sense of the IBC), his mobile terminal, temporarily positioned in reader mode, transmits the frame IBC which passes through his body, then through that of user 2, and reaches the mobile terminal of user 2, TM, positioned in emulation mode. By recognizing the IBC frame, thanks to the protocol that has been detailed in support of the , or the simplified protocol proposed in support of the , the mobile terminal TM_R of the user 2 establishes the communication IBC with that of the user 2′, TM_E, via the activation of the return channel CR, according to the Bluetooth example. The first user can stop touching the second, the file P is transferred and the return channel optionally closed.

In the context of the , the TM_E user is positioned in NFC and the other in IBC. When the user 2' touches the user 2 with his mobile terminal TM_E (or the reverse, it does not matter as long as the mobile terminal TM_E and the user 2 are close in the NFC sense), this mobile terminal, positioned transiently in reader mode, transmits the IBC frame which passes through the body of the user 2, and reaches the mobile terminal of the user 2, TM_R, positioned in emulation mode. By recognizing the IBC frame, thanks to the protocol that has been detailed in support of the , or the simplified protocol proposed in support of the , the mobile terminal of the user 2 establishes the communication IBC with that of the user 2′, TM_E, via the activation of the return channel CR, for example in Bluetooth. The first user can stop touching the second, the P file is transferred and the return channel closed.

Optionally, in both cases, the closing of the channel is accompanied by the deactivation of the corresponding means of communication (Bluetooth, Wi-Fi, mobile data), in particular if it was deactivated before the start of data transfer.

It will be noted that it is rare for a mobile telephone to position itself in reader mode because the power required during “polling” is high, and therefore prohibitive for the battery. However, if the user 2' has checked the IBC-S application, the mobile terminal TM_E can be positioned in reader mode in a controlled manner, either for a limited period of time, or for the sole duration of sending the message d 'IBC invitation, which reduces the problem of power consumption, and therefore battery. There illustrates this aspect.

There illustrates steps of a data transfer method in IBC mode according to one embodiment of the invention.

According to this embodiment, a mobile terminal TM_E equipped with NFC and IBC of a user 2' seeks to transmit voluminous data to another mobile terminal TM_R equipped with IBC of a user 2, according to one of the two contexts presented respectively in FIGS. 6 and 7, that is to say that the transaction takes place when the user 2′ approaches either his mobile terminal TM_E ( ), or his hand ( ), of user 2 who for his part keeps his mobile terminal TM_R in his pocket.

We will now describe the in support of the following steps E30 to E58:

During an initialization step E30, the receiving mobile terminal TM_R activates its NFC module (CLF and antenna). By default, the “card emulation” mode is generally chosen on a mobile terminal. Then he positions himself in IBC mode (M_IBC) and selects the “IBC-S” option which corresponds to an IBC data transfer application. According to the example of figures 6 and 7, he ticks the two corresponding boxes on the screen of his smartphone, via the HMI module, for example in the parameters of the mobile terminal (checkbox in the connectivity options of the terminal), or on screen for the duration of the transaction. The IBC mode and the IBC-S application can therefore be positioned by default for the TM_R mobile terminal, i.e. it can operate for several transactions without user intervention.

During an initialization step E50, the mobile terminal TM_E has activated its NFC module (CLF and antenna). By default, the “card emulation” mode is generally chosen on a mobile terminal. Then he positions himself in IBC (M_IBC) or NFC (M_NFC) mode and selects the “IBC-S” option which corresponds to an IBC data transfer application. According to the example of figures 6 and 7, he ticks the corresponding boxes on the screen of his smartphone, via the HMI module, for example in the parameters of the mobile terminal (checkbox in the connectivity options of the terminal for example) , or on screen for the duration of the transaction. IBC mode ( ) or NFC mode ( ), as well as the IBC-S option (FIGS. 6 and 7) can be positioned by default for the mobile terminal TM_E, that is to say that it can operate for several transactions without user intervention.

During a transfer initialization step E51, the user decides to use the “IBC-S” option to effectively transfer data P to the mobile terminal TM_R of user 2, which is in his pocket . The user 2′ launches an application for this purpose, for example an APP_IBC-S applet of the PGR′ program. The applet can be selected by the user (for example on the screen of his smartphone) or launched automatically when he selects a content to be transferred, for example via a menu selection which appears on the screen to indicate that the content (P) can be transferred in IBC, or any other possibility to initiate the transfer of the content (P) to the user 2 in IBC mode.

During a step E52, the mobile terminal TM_E is positioned in NFC reader mode, as defined previously. Such positioning is done automatically and cyclically on some of the NFC mobile terminals on the market during the polling phase, which is preferably very short because it consumes energy. On other mobile terminals on the market, the polling phase is only triggered when a contactless card is detected. Positioning in reader mode of step E52 is therefore either automatic or forced.

During a step E53, the method arms a timer (T_LEC) of the reader mode. Such a delay, corresponding to the maximum duration of the time during which the mobile terminal can remain in reader mode, is also called “time-out”. It is conventionally monitored in the background by the system processor associated with a clock. For example, T_LEC can take the value 10 seconds. Indeed, the TM_E mobile terminal cannot remain in reader mode for long, which would drain its batteries. This step is optional because it is possible to deactivate the reader mode after the transmission of the IBC invitation message. However, it is useful in the event that this transmission fails, because it prevents the mobile terminal from remaining unnecessarily long in reader mode.

Throughout the duration of the process, during step E54, the mobile terminal TM_E therefore tests the time elapsed since the arming of the timer T_LEC. It can perform this step in the background. If the time is exceeded, it deactivates reader mode and returns for example to step E50 or E51.

During a step E55, the method prepares the invitation message WUP_IBC for the type of sub-standard targeted, in this case IBC (since, even if the mobile terminal TM_E is in M_NFC mode, its recipient, the mobile terminal TM_R, is in M_IBC mode), in order to transfer content (video P). The WUP_IBC message can contain the IBC application type, here IBC-S, (as proposed in the "Type" field of the WUB_IBC(2) message of the ). It can also contain a random value, the type of return channel to use, and/or any other data useful for the operation of the service.

Then the user 2 comes into proximity to the user 2', either by approaching his mobile terminal TM_E, or by approaching a part of his body, thereby authorizing the transmission of the carrier wave of the WUP_IBC invitation message to through the user's body 2'. For example, one of the 2 or 2' users puts their hand on the other's shoulder, or they shake hands, etc. The mobile terminal TM_R receives the electromagnetic field, and therefore the WUP_IBC message, generated by the mobile terminal TM_E.

According to this embodiment, the method deactivates the reader mode as soon as the message is transferred, during step E56. The TM_E mobile terminal, whether in NFC or IBC mode, is repositioned in card emulation mode.

The WUP_IBC invitation message is received by the mobile terminal TM_R in step E31.

During step E32, the mobile terminal TM_R decodes the message received (type of communication, hazard, type of service, etc.). He can in particular verify that it is indeed an IBC invitation message (as explained for example in support of Figures 4 and 5), and that the type of IBC application received (IBC-S) corresponds to its configuration. It can also read and encrypt the random number received, and find out the type of return channel desired. If the invitation message is correct, it initializes the return channel (BT, Wi-Fi, etc.) and sends an IBC transaction confirmation, possibly accompanied by the encrypted random number, denoted ACK_IBC, on this channel.

The mobile terminal TM_E validates or not the communication during step E57 upon receipt of the response message, depending on the content of said response message (it is indeed an IBC acknowledgment on the correct channel with the correct random number, etc.). Then he deactivates reader mode.

The communication continues on the return channel during steps E33 and E58, for the reception/transmission of messages relating to the transfer of the file P.

When the transfer is complete, the file P can be displayed for example on the screen of the mobile terminal TM_R. Optionally, a text or sound message can be communicated to user 2 of the TM_R terminal. Then optionally, the CR return channel is closed and the IBC-S option may or may not be unchecked.

It goes without saying that the embodiments which have been described above have been given purely as an indication and in no way limiting, and that many modifications can be easily made by those skilled in the art without departing from the scope. of the invention.

Claims (15)

Method for transferring data from a mobile terminal (TM_E) equipped with a near-field communication module (NFC'), said mobile terminal being capable of positioning itself in an NFC mode (M_NFC) or in an IBC mode (M_IBC ) to perform contactless transactions, the method being characterized in that it comprises, on the mobile terminal (TM_E), the following steps:
- select (E50) the NFC mode (M_NFC) or the IBC mode (M_IBC);
- positioning (E52) the mobile terminal in NFC reader mode;
- send (E55) an invitation message (WUP_IBC) according to a type of near-field communication IBC (NFC-IBC);
- deactivate (E56) the NFC reader mode;
- receive (E57) a pairing message (ACK_IBC) on a return channel (CR) separate from the near-field channel;
- transfer (E58) the data to the return channel (CR). Method for transferring data from a mobile terminal (TM_E) according to the preceding claim, characterized in that it further comprises, after the step of positioning (E52) the mobile terminal in NFC reader mode:
- a step (E53) of arming a reader mode timer (T_LEC);
- a step (E54) for deactivating reader mode if the timeout is exceeded. Method for transferring data from a mobile terminal (TM_E) according to one of the preceding claims, characterized in that the IBC or NFC mode is selected (E50) via a man-machine interface (HMI') of the mobile terminal. Method for transferring data from a mobile terminal (TM_E) according to one of the preceding claims, characterized in that an IBC application type (IBC-S) is selected (E51) via a man-machine interface of the terminal mobile. Method according to one of the preceding claims, characterized in that said invitation message (WUP_IBC) contains one or more data from among:
- a hazard to establish the return channel;
- an IBC application type (AFI, Type, IBC-S);
- a type of return channel (BT, Wi-Fi);
- a service parameter. Device for transferring data from a mobile terminal (TM_E) equipped with a near-field communication module (NFC'), said device being capable of positioning the mobile terminal in an NFC mode (M_NFC) or in an IBC mode ( M_IBC) to perform contactless transactions, characterized in that it is configured to implement at the mobile terminal:
- select (E50) the NFC mode (M_NFC) or the IBC mode (M_IBC);
- positioning (E52) the mobile terminal in NFC reader mode;
- send (E55) an invitation message (WUP_IBC) according to a type of near-field communication IBC (NFC-IBC);
- deactivate (E56) the NFC reader mode;
- receive (E57) a pairing message (ACK_IBC) on a return channel (CR) separate from the near-field channel;
- transfer (E58) the data to the return channel (IBC). Method for receiving data on a mobile terminal (TM_R) equipped with a near-field communication module (NFC'), said mobile terminal being able to position itself in an IBC mode (M_IBC) to carry out contactless transactions, the method being characterized in that it comprises on the mobile terminal (TM_R) the following steps:
- positioning (E30) the mobile terminal (TM_R) in IBC mode (M_IBC);
- receiving (E31) an invitation message (WUP_IBC) according to a type of near-field communication IBC (NFC-IBC);
- Transmit (E32) a pairing message (ACK_IBC) on a return channel separate from the near-field channel;
- receive (E58) the data on the return channel (IBC). Method for receiving data on a mobile terminal according to Claim 7, characterized in that the IBC mode is selected (E30) via a man-machine interface (HMI) of the mobile terminal (TM_R). Method for receiving data on a mobile terminal according to Claim 7 or 8, characterized in that an IBC application type (IBC-S) is selected (E30) via a man-machine interface of the mobile terminal and/or received in the invitation message. Method for receiving data on a mobile terminal according to one of Claims 7 to 9, characterized in that the type of return channel is received in the invitation message (WUP_IBC). Device for receiving data from a mobile terminal (TM_R) equipped with a near-field communication (NFC) module, said device being capable of positioning the mobile terminal in an IBC mode (M_IBC) to carry out contactless transactions, characterized in that it is configured to implement at the mobile terminal:
- positioning (E30) the mobile terminal (TM_R) in IBC mode (M_IBC);
- receiving (E31) an invitation message (WUP_IBC) according to a type of near-field communication IBC (NFC-IBC);
- Transmit (E32) a pairing message (ACK_IBC) on a return channel separate from the near-field channel;
- receive (E58) the data on the return channel (IBC). System comprising a transmitting mobile terminal (TM_E) equipped with a transfer device according to claim 6 and a receiving mobile terminal (TM_R) equipped with a receiving device according to claim 11, characterized in that the data transfer is triggered when the transmitting mobile terminal positioned in NFC mode comes close to the body of the user of the receiving mobile terminal. System comprising a transmitting mobile terminal (TM_E) equipped with a transfer device according to claim 6 and a receiving mobile terminal (TM_R) equipped with a receiving device according to claim 11, characterized in that the data transfer is triggered when the body of the user of the transmitting mobile terminal positioned in IBC mode comes into proximity to the body of the user of the receiving mobile terminal. Computer program capable of being implemented on a transmitting mobile terminal equipped with a transfer device according to claim 6, the program comprising code instructions which, when the program is executed by a processor, carry out the steps of the method defined according to one of claims 1 to 5. Computer program capable of being implemented on a receiving mobile terminal equipped with a reception device according to claim 11, the program comprising code instructions which, when the program is executed by a processor, carry out the steps of the method defined according to one of claims 7 to 10.