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EP-4741868-A2 - METHOD FOR TRANSCEIVING A MESSAGE FOR UWB DISTANCE MEASUREMENT, METHOD AND SYSTEM FOR DISTANCE MEASUREMENT AND TRANSCEIVER FOR UWB DISTANCE MEASUREMENT

EP4741868A2EP 4741868 A2EP4741868 A2EP 4741868A2EP-4741868-A2

Abstract

Method for transceiving a message (M) for UWB distance measurement: transceiving a first information portion (A) via a narrowband channel; transceiving after the first information portion a second information portion (B) via a UWB channel, wherein the second information portion (B) comprises a distance pulse sequence being a pulse sequence to be used for distance measurement; wherein the first information portion (A) is transceived in the narrowband channel on a first carrier signal, wherein the second information portion (B) is transceived in the UWB channel on a second carrier signal, wherein the first carrier signal and the second carrier signal are generated by the same oscillator (12).

Inventors

  • DANEV, BORIS
  • BARRAS, DAVID

Assignees

  • Infineon Technologies Switzerland AG

Dates

Publication Date
20260513
Application Date
20220518

Claims (15)

  1. Device for receiving a message for UWB distance measurement, comprising : a receiver (RX) configured to receive a first information portion (A) via a narrowband channel and to receive after the first information portion (A) a second information portion (B) via a UWB channel, wherein the second information portion comprises a distance pulse sequence for distance measurement, wherein the receiver (RX) comprises a receiving circuit configured to be operated in a narrowband mode for receiving in the narrowband channel and in an UWB mode for receiving in the UWB channel, wherein the receiving circuit comprises an oscillator (12) configured to generate in the narrowband mode a first carrier signal for the narrowband channel as the carrier signal of the oscillator and in the UWB mode a second carrier signal for the UWB channel as the carrier signal of the oscillator (12).
  2. Device according to claim 1, wherein the receiving circuit comprises a mixer (22) configured, in the narrowband mode, to downmix the received radio signal with the first carrier signal obtained from the oscillator (12), and, in the UWB mode, to downmix the received radio signal with the second carrier signal obtained from the oscillator (12).
  3. Device according to claim 2, wherein the receiving circuit comprises an analogue to digital converter (24) configured to convert the downmixed signal into a digital signal, wherein the analogue to digital converter (24) uses in the narrowband mode a first sampling frequency and in the UWB mode a second sampling frequency, wherein the first sampling frequency is lower than the second sampling frequency, wherein the receiving circuit comprises a digital processor configured to process the digital signal.
  4. Device according to claim 3, wherein the receiving circuit comprises a filter (23) configured to generate a filtered signal by, in the narrowband mode, filtering out from the downmixed radio signal the frequencies outside of the narrowband channel before converting the downmixed signal in the analogue to digital converter (24) and, in the UWB mode, by filtering out from the downmixed radio signal the frequencies outside of the UWB channel before converting the downmixed signal in the analogue to digital converter (24).
  5. Device according to one of claims 1 to 4, wherein the receiver (RX) is a transceiver configured to transmit a first transmit information portion (A) via the narrowband channel and to transmit after the first transmit information portion (A) a second transmit information portion (B) via the UWB channel, wherein the second transmit information portion comprises a transmit distance pulse sequence for distance measurement, wherein the receiving circuit is a transceiving circuit comprising a signal generator (31) configured, in the narrowband mode, to modulate a narrowband signal and/or the first transmit information portion (A) on the first carrier signal received from the oscillator (12) and, in the UWB mode, to modulate an UWB signal and/or the second transmit information portion (B) on the second carrier signal received from the oscillator (12).
  6. Device according to the previous claim, wherein the transceiving circuit comprises: a transmission amplifier configured to amplify the modulated radio signal, an antenna configured to transmit the amplified modulated radio signal and configured to receive the radio signal; a receiving amplifier configured to amplify the radio signal received at the antenna before downmixing the received radio signal.
  7. Device according to one of the previous claims, wherein the receiver (Rx) determines a clock offset based on the first information portion (A), wherein the clock-offset defines the offset of the system clock of the receiver (RX) from a system clock of a transmitter of the message, wherein the receiver (RX) detects the second information portion (B) of the message using the system clock of the receiver (RX) and the clock-offset determined based on the first information portion (A), wherein the system clock of the receiver (RX) is defined by the frequency of the oscillator (12).
  8. Device according to the previous claim, wherein the receiver (RX) is configured to receive the second information portion (B) in the UWB channel without synchronization in the UWB channel.
  9. Device for transmitting a message for UWB distance measurement, comprising : a transmitter (TX) configured to transmit a first information portion (A) via a narrowband channel and to transmit after the first information portion (A) a second information portion (B) via a UWB channel, wherein the second information portion comprises a distance pulse sequence for distance measurement, wherein the transmitter (TX) comprises a transmitting circuit configured to be operated in a narrowband mode for transmitting in the narrowband channel and in an UWB mode for transmitting in the UWB channel, wherein the transmitting circuit comprises an oscillator (12) configured to generate in the narrowband mode a first carrier signal for the narrowband channel as the carrier signal of the oscillator and in the UWB mode a second carrier signal for the UWB channel as the carrier signal of the oscillator (12).
  10. Device according to the previous claim, wherein the transmitter circuit comprises a signal generator (31) configured, in the narrowband mode, to modulate a narrowband signal and/or the first information portion (A) on the carrier signal received from the oscillator (12) and, in the UWB mode, to modulate an UWB signal and/or the second information portion (B) on the carrier signal received from the oscillator (12).
  11. Device according to one of previous claims, wherein the narrowband channel has a carrier frequency between 5 GHz and 6 GHz or between 8.5 GHz and 9 GHz and the UWB channel has a carrier frequency between 6 GHz and 8.5 GHz.
  12. Device according to the previous claim, wherein the transmitter circuit comprises a transmission amplifier (32) configured to amplify the modulated radio signal.
  13. Device according to one of the previous claims, wherein the second information portion (B) does not contain a message portion header comprising a preamble, a start of frame delimiter and packet header.
  14. System for distance measurement between a verifier (V) and prover (P) comprising the verifier (V) and the prover (P), wherein the verifier (V) is configured to send a first message (C, M1) with a first pulse sequence (N, Nv) to the prover (P), wherein the prover (P) is configured, after having received the first message, to send a second message (R, M2) with a second pulse sequence (N, Np) to the verifier (V), wherein the verifier (V) is configured to measure the distance (ToF) between the verifier (V) and the prover (P) based on the verifier time difference (DTv), wherein the verifier time difference (DTv) is the time difference between sending the first message from the verifier (V) and receiving the second message at the verifier (V); characterized in that the verifier (V) comprises a device according to one of claims 5 to 8 for transmitting the first message (C, M1) and/or for receiving the second message (R, M2), and/or the prover (P) comprises a transceiver according to one of claims 5 to 8 for transmitting the second message (R, M2) and/or for receiving the first message (C, M1).
  15. Method for transceiving a message for UWB distance measurement, comprising the steps of : transceiving a first information portion via a narrowband channel, and transceiving after the first information portion a second information portion via a UWB channel, wherein the second information portion comprises a distance pulse sequence being a pulse sequence to be used for distance measurement, wherein the first information portion (A) is transceived in the narrowband channel on a first carrier signal, wherein the second information portion (B) is transceived in the UWB channel on a second carrier signal, wherein the first carrier signal and the second carrier signal are generated by the same oscillator (12).

Description

Technical Field The present invention relates to the field of ultrawideband (UWB) distance measurement, in particular for UWB secure distance measurement. Prior art UWB secure distance measurement is well known. A verifier V sends in an UWB channel a challenge message C1 with a challenge pulse sequence Nv to a prover P which sends a response message R1 with a response pulse sequence Np in the UWB channel back to the verifier V as shown in Fig. 1. Due to the verifier time difference DTv between sending the challenge message C1 and receiving the response message R1, the time of flight of the two messages C1 and R1 can be determined and thus the distance between the verifier and the prover. Owing to the use of the UWB channel, the challenge pulse sequence Nv and the response pulse sequence Np can be sent with very short pulses of a length of 1-2 ns so that the distance between the verifier and the prover can be determined with a small error. The authenticity of the prover P can be verified based on the response pulse sequence Np and on authentication information. The authenticity of the prover P can be verified by the verifier V for example with authentication information transmitted from the prover P to the verifier. This authentication information comprises for example the Nv received at the prover P, the response pulse sequence Np transmitted and a message authentication code (MAC) of the received Nv and the transmitted Np using a shared secret key K. This authenticated message is not time critical and can be sent by the prover using the UWB channel or out-of-band (oob) channel, typically a narrow-band channel for data communication. In modern cars an UHF (315/433 MHz) narrowband channel is used. The challenge message C1 and the response message R1 require in addition to the pulse sequences Nv and Np further additional message information which makes the transferred UWB messages much longer than the Nv and Np. As shown in Fig. 2, any message transmitted in a UWB channel (or any other channel) requires in the physical layer PHY of the OSI model a synchronization header SHR, a physical header PHR and in the physical payload P the data to be transmitted. In the messages exchanged for measuring the distance measurement, P contains the challenge/response pulse sequence. The physical payload comprises normally information about the source address, the destination address (also known as MAC header (MHR)), the service set identifier (SSID) and for the distance measurement the pulse sequence Np or Nv. When the secure distance measurement protocol requires in addition to exchange certain information, e.g. for authentication, like the encrypted response pulse sequence Np, the encrypted Nv or the encrypted SSID, the UWB messages get even longer. While the UWB channel has the advantage of the wide bandwidth for generating very short impulses for the precise determination of the distance and for the security of the measurement against malicious third parties, it has also some disadvantages. One major disadvantage is the high power consumption of the UWB communication especially at the receiver which needs to sample the received signal at a very high sampling rate to catch/capture the fast varying signal enabled by the large bandwidth of the UWB channel of large bandwidth of the UWB channel. An UWB receiver consumes in the same time around ten times more than a narrowband receiver (NB) on a similar carrier frequency. Therefore, even if the UWB channel can be used as a data exchange link, normally it is tried to send all data which are not relevant for the distance measurement via a separate out of band message O (typically a narrowband data link) as shown in Fig. 1. One advantage of the out of band O message is that this allows to correct bit errors in the Nv and/or Np during the UWB exchange and therefore increase the performance of the ultra-wideband measurement. The out of band message O is transferred thus via a separate communication channel which requires less power to transfer the data and may have more robust data communication capabilities. Normally a NB channel, e.g. with a UHF carrier frequency is used, or 2.4. GHz Bluetooth (BT) or Zigbee. This reduces the power consumption significantly. However, this has the disadvantage that the secure distance measurement requires not only a UWB communication chip, but also a NB communication chip like a BT or Zigbee chip. This increases the constructional complexity for the secure distance measurement and the coordination complexity between the different communication chips. In addition, the existing NB channels like BT or Zigbee are very slow and have a large communication management overload which makes the coordination with the UWB very difficult. Since the power consumption of the receiver depends also on the carrier frequency of the message, some secure distance protocols like in US2020/198580 use a wake-up message W at a low frequency (LF) carrier frequency with a N