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    Öğe
    Error Analysis of the Joint Localization and Synchronization of RIS-Assisted mm-Wave MISO-OFDM Under the Effect of Hardware Impairments
    (Ieee-Inst Electrical Electronics Engineers Inc, 2022) Ceniklioğlu, Büşra; Tubail, Deeb Assad; Canbilen, Ayşe Elif; Develi, İbrahim; Ikki, Salama S.
    This work investigates the theoretical bounds of the joint localization and synchronization processes in a reconfigurable intelligent surface (RIS)-assisted system. We address the case of millimeter-wave ( $mm$ -Wave) multiple-input single-output (MISO) orthogonal frequency-division multiplexing (OFDM) with non-ideal transceivers. Considering a single antenna mobile station (MS) aims to estimate the parameters of the downlinks from the base station (BS) and the RIS by observing a known sequence received by the MS directly from the BS and indirectly through the RIS. The theoretical bounds of the estimation process are assessed by using the Fisher information matrix (FIM). A transformation matrix is then used to convert the FIM of the downlink channel parameters to the FIM of the MS joint localization and synchronization parameters. Specifically, the transformation matrix is derived based on the geometric relationships that convert the estimated downlink channels' parameters to the position coordinates and clock offset. Next, the Cramer-Rao lower bound (CRLB) matrix of the joint localization and synchronization process is obtained by using the pseudo-inverse of the FIM. Thus, the position error bound (PEB), as well as the synchronization error bound (SEB), are calculated. Computer simulation results are provided to illustrate the adverse effects of the hardware impairments (HWIs) on the accuracy of localization and synchronization. These results are given in proportion to the effective signal-to-noise ratio (SNR), the number of pilot transmissions, and the number of the RIS elements.
  • [ X ]
    Öğe
    Error Bounds for 3D Localization and Maximum Likelihood Estimation of mm-Wave MISO OFDM Systems in the Presence of Hardware Impairments
    (Ieee-Inst Electrical Electronics Engineers Inc, 2022) Tubail, Deeb Assad; Ceniklioğlu, Büşra; Canbilen, Ayşe Elif; Develi, İbrahim; Ikki, Salama
    Millimeter-wave (mm-wave) multiple-input single-output (MISO) systems are expected to be extremely advantageous for the fifth generation (SG) cellular systems. In fact, these systems are considered key enablers of centimeter-level localization accuracy, even in the case of a single base station (BS). However, there are still fundamental issues that need to be addressed when applying mm-wave MISO systems to practical scenarios, namely the effects of hardware impairments (HWIs). In this study, the 3D localization accuracy of mm-wave MISO OFDM systems is investigated when there are HWIs at both the BS and the mobile station (MS). The localization is performed by estimating the downlink channel parameters of the line-of-sight (LOS) path using only a maximum likelihood (ML) estimator at the MS. We then transform these channel parameters into ones for localization. The Fisher information matrix (FIM) is employed to assess the accuracy of the estimation processes, considering also any non-LOS (NLOS) paths. The limit of localization is calculated in terms of the position error bound (PEB). Computer simulations demonstrate the destructive impacts of HWIs on the localization process. Moreover, it was proven that the effect of NLOS paths from unknown scatters on the localization process is related to the ratio between LOS and NLOS path gains.