Sub-GHz Two-Way Ranging Based on Phase Detection for Remote Keyless Entry Systems

Ichiro Seto, Shoji Otaka, Hiroshi Yoshida, Katsuya Nonin, Masaki Nishikawa, Takayuki Kato, Yoshiharu Nito, Hideyuki Ishiwata, Tomoaki Otsuki

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Remote keyless entry systems have penetrated the vehicular market due to its convenience. However, its vulnerability against relay attacks exploiting the wireless channel is a serious threat. One of the prominent countermeasures is radio ranging between the key fob and the vehicle. Taking into account radio regulations, usability and power consumption among other things, a suitable approach is necessary to devise. This article proposes sub-GHz two-way ranging based on phase detection which offers high tolerance against reference clock offset between a pair of transceiver devices and a novel compensation scheme against multipath effects. We present the operation principle and theoretical performance under a two-path model of radio propagation and additive white Gaussian noise. In field experiments with prototype devices, the ranging accuracy is validated. We show that the proposed ranging produces sufficient performance for remote keyless entry systems, confirming if the key fob is within a few meters of the vehicle.

Original languageEnglish
Pages (from-to)9705-9720
Number of pages16
JournalIEEE Transactions on Vehicular Technology
Issue number9
Publication statusPublished - 2022 Sept 1


  • Sub-GHz
  • clock offset
  • multipath
  • phase detection
  • relay attack
  • remote keyless entry
  • two-way ranging

ASJC Scopus subject areas

  • Aerospace Engineering
  • Electrical and Electronic Engineering
  • Computer Networks and Communications
  • Automotive Engineering


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