The invention concerns an automatic access and starting system for a motor vehicle, comprising an on-board access management system and at least one identifier (3) such as an electronic key, the access management system being configured to detect and authenticate the identifier (3) when it is close to the vehicle (1), the identifier (3) being configured to emit an authentication signal in response to an interrogation signal emitted by the management and access system, the identifier (3) comprising a memory for storing an instruction relative to a command issued by the carrier of the identifier (3) if this command is issued during the phase of detection and authentication by the on-board system, the instruction being stored temporarily in order for the identifier to be able to emit a signal related to the command when the detection and authentication phase is complete.

According to certain examples, a circuit-based wireless communications system provides secure access to a vehicle by way of certain circuitry configure to compare a first RF background observed for a vehicle-located RF receiver that is part of a vehicle-located circuit secured to a vehicle, with a second RF background observed for a wireless-communications vehicle-access circuit that includes another RF receiver. In response, a distance metric is generated to indicate a degree of similarity between the first RF background and the second RF background, and based on whether this metric satisfies a threshold, access to the vehicle may be granted via the wireless-communications vehicle-access circuit.

A system for includes master and sniffer devices. The master device includes: first antennas with different polarized axes; a transmitter transmitting a challenge signal via the first antennas from the vehicle to a slave device, where the slave device is a portable access device; and a receiver receiving a response signal in response to the challenge signal from the slave device. The sniffer device includes: second antennas with different polarized axes; and a receiver receiving, via the second antennas, the challenge signal from the transmitter and the response signal from the slave device. The sniffer device measures when the challenge signal and the response signal arrive at the sniffer device to provide arrival times. The master or sniffer device estimates at least one of a distance from the vehicle to the slave device or a location of the slave device relative to the vehicle based on the arrival times.

A method of controlling a smart key, including a low frequency (LF) receiver receiving an LF signal from a vehicle, a radio frequency (RF) transmitter transmitting an RF signal to the vehicle in response to the LF signal, a sensor unit sensing a motion, and a micro control unit controlling operations of the LF receiver, the RF transmitter, and the sensor unit, includes receiving, by the LF receiver, the LF signal from the vehicle and controlling, by the micro control unit, a turn-on/off operation of each of the LF receiver, the RF transmitter, and the sensor unit on the basis of the received LF signal.

A remote keyless entry system includes an in-vehicle device including an in-vehicle device controller, an in-vehicle device transmitter that transmits an in-vehicle device signal, and an in-vehicle device receiver that receives a portable device signal, and a portable device including a portable device controller, an acceleration sensor, a portable device receiver, and a portable device transmitter, wherein the portable device controller calculates a distance from the in-vehicle device to the portable device based on the in-vehicle device signal, calculates a first travel distance based on acceleration, and causes the portable device transmitter to transmit the portable device signal including at least the distance, the in-vehicle device controller receives the portable device signal multiple times and calculates a second travel distance based on distances included in received portable device signals, and whether a relay attack is performed is determined based on the first travel distance and the second travel distance.

According to an embodiment, a first device includes: a first transceiver configured to transmit two or more first carrier signals using an output of a first reference signal source and to receive two or more second carrier signals; and a calculation unit, and a second device includes: a second transceiver configured to transmit the two or more second carrier signals using an output of a second reference signal source that operates independently of the first reference signal source and to receive the two or more first carrier signals. A frequency group of the two or more first carrier signals and a frequency group of the two or more second carrier signals are identical or substantially identical to each other, and the calculation unit calculates the distance between the first device and the second device based on a phase detection result obtained by receiving the first and second carrier signals.

A first device includes: a first reference signal source; a first transmitting/receiving unit which transmits two or more first carrier signals and receives two or more second carrier signals using an output of the first reference signal source; and a calculating unit. A second device includes: a second reference signal source configured to be operated independently from the first reference signal source; and a second transmitting/receiving unit configured to transmit two or more second carrier signals and receive two or more first carrier signals using an output of the second reference signal source. A frequency group of two or more first carrier signals and a frequency group of two or more second carrier signals differ from each other. The calculating unit calculates a distance between the first device and the second device based on a phase detection result obtained by receiving the first and second carrier signals.

The performance of an action for a transportation vehicle, wherein a relay attack is prevented. In response to a transmission of a first radio signal at a first frequency, on the one hand, a second radio signal at a second frequency is received from an ID transponder authorized for the transportation vehicle and, on the other hand, a further radio signal at the first frequency is received. The action is performed for the transportation vehicle only in response to the second radio signal originating from an ID transponder authorized for the transportation vehicle and only in response to the signal strength of the further radio signal lying below a predefined signal strength threshold.

There is provided a method and a system for authorizing a user device to send a request to a vehicle in order to prevent a physical layer relay attack. The system comprises a vehicle comprising an acoustic transducer and an RF transceiver and a user device comprising an acoustic transducer and an RF transceiver. The method relates to a signaling scheme using a combination of acoustic and RF signals for preventing a successful physical layer relay attack.

A method of transmitting signals from a first node having multiple transceivers to a second node is disclosed. The method comprises receiving a message from the second node at the first node, wherein the message is received by each of a plurality of transceivers of the first node; and transmitting by each of the plurality of transceivers a respective data frame to the second node in response to the message; wherein each transceiver initiates the transmission of its respective data frame a predetermined time period after receipt of the message by the transceiver; and wherein the transmissions of the data frames from the plurality of transceivers overlap. The data frames may form part of a two-way ranging exchange.