Method for radio communication of a slave device with a master device

1. A method of radio communication of a slave device with a master device, the method being carried out by the slave device and comprising:

receiving a connection request sent by the master device comprising first communication parameters for communicating with the master device, the communication parameters being indicative of a sequence of frequency channels to be used during successive periods to communicate with the master device;

communicating with the master device using the first communication parameters,

during one of the periods, implementing a processing causing the master device to send a connection update comprising second communication parameters, the processing comprising an action on one of the frequency channels causing the master device to detect a degradation in communication quality on the frequency channel;

receiving the connection update; and

communicating with the master device using the second communication parameters in place of the first communication parameters.

2. The method according to claim 1 , wherein the processing comprises sending a connection update request to the master device, the action being selectively implemented when the slave device detects that the parameter update request has not been processed by the master device.

3. The method according to claim 1 , wherein the connection update request is encrypted by the slave device before being sent.

4. The method according to claim 1 , wherein the action on one of the frequency channels comprises the sending on the frequency channel of a message comprising a distorted content simulating a transmission error, such as a message comprising payload data and a cyclic redundancy code with a value indicating an error in the payload data.

5. The method according to claim 1 , wherein the action on one of the frequency channels comprises not sending a response expected by the master device on the frequency channel.

6. The method according to claim 1 , wherein the frequency channel on which the action is performed is randomly selected by the slave device from among several frequency channels.

7. The method according to claim 1 , further comprising a countermeasure step when the slave device does not receive the frequency connection update within a predetermined time or after receiving a predetermined number of packets sent by the master device, the countermeasure step comprising at least one of the following operations:

sending a connection interruption message to the master device,

sending an alert message informing the master device that the radio communication is not secure against relay attacks,

shutting down radio communication with the master device.

8. The method according to claim 1 , comprising:

after receiving the connection update, receiving by the slave device of N consecutive packets from the master device, where N≥1,

comparing the communication parameters used for the transmission of the N consecutive packets to the slave device against the second communication parameters,

when the compared parameters do not match, implementing by the slave device of a countermeasure step comprising at least one of the following operations:

sending a connection interruption message to the master device,

sending an alert message informing the master device that the radio communication is not secure against relay attacks,

shutting down radio communication with the master device.

9. The method according to claim 1 , wherein the slave device uses a low-power Bluetooth protocol to communicate with the master device.

10. A computer program product comprising program code instructions for executing the steps of the method according to claim 1 , when said program is executed by a master or slave device.

11. A non-transitory computer-readable memory storing instructions executable by the computer for the execution of the steps of the method according to claim 1 .

12. The method of claim 1 , wherein the connection update is transmitted by the master device to the slave device in at least one of the frequency channels.

13. A slave device ( 2 ) comprising:

a radio communication interface for:

receiving a connection request sent by a master device and comprising first communication parameters for communicating with the master device, the communication parameters being indicative of a sequence of frequency channels to be used during successive periods to communicate with the master device,

communicating with the master device using the first communication parameters;

receiving a connection update sent by the master device, wherein the connection update comprises second communication parameters,

communicating with the master device using the second communication parameters in place of the first communication parameters,

a processing unit configured to implement, during one of the periods, a processing capable of causing the master device to send the connection update, the processing comprising an action on one of the frequency channels capable of causing the master device to detect a degradation in communication quality on the frequency channel.

14. A system comprising:

a slave device according to the preceding claim 13 , and

a master device configured to send the connection update.