Device-Free Sensing in OFDM Cellular Network

Qin Shi, Liang Liu, Shuowen Zhang, Shuguang Cui

Research output: Journal article publicationJournal articleAcademic researchpeer-review

12 Citations (Scopus)


This paper considers device-free sensing in an orthogonal frequency division multiplexing (OFDM) cellular network to enable integrated sensing and communication (ISAC). A novel two-phase sensing framework is proposed to localize the passive targets that cannot transmit/receive reference signals to/from the base stations (BSs), where the ranges of the targets are estimated based on their reflected OFDM signals to the BSs in Phase I, and the location of each target is estimated based on its ranges to different BSs in Phase II. Specifically, in Phase I, we design a model-free range estimation approach by leveraging the OFDM channel estimation technique for determining the delay values of all the two-way BS-target-BS paths, which does not rely on any BS-target channel model. In Phase II, we reveal that ghost targets may be falsely detected in some cases as all the targets reflect the same signals to the BSs, which thus do not know how to match each estimated range with the right target. Interestingly, we show that the above data association issue is not a fundamental limitation for device-free sensing: under the ideal case of perfect range estimation in Phase I, the probability for ghost targets to exist is proved to be negligible when the targets are randomly located. Moreover, under the practical case of imperfect range estimation in Phase I, we propose an efficient algorithm for joint data association and target localization in Phase II. Numerical results show that our proposed two-phase framework can achieve very high accuracy in the localization of passive targets, which increases with the system bandwidth.

Original languageEnglish
Article number9724258
Pages (from-to)1838-1853
Number of pages16
JournalIEEE Journal on Selected Areas in Communications
Issue number6
Publication statusPublished - 1 Jun 2022


  • 6G
  • Integrated sensing and communication (ISAC)
  • data association
  • device-free sensing
  • ghost target
  • localization
  • networked sensing
  • orthogonal frequency division multiplexing (OFDM)

ASJC Scopus subject areas

  • Computer Networks and Communications
  • Electrical and Electronic Engineering


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