Browsing by Author "Ikki, Salama"

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Citation - WoS: 11
Citation - Scopus: 14
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, Buşra; Canbilen, Ayşe Elif; Develi, Ibrahim; 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.
Citation - WoS: 2
Citation - Scopus: 2
Estimation of Random Channel Gain for Sisovisible Light Communications System
(Ieee Canada, 2023) Yaseen, Maysa; Canbilen, Ayse E.; Ikki, Salama
In this article, the estimation of random channel gain is studied for a single-input single-output (SISO) visible light communication (VLC) system. Five different estimators, namely maximum likelihood (ML), least square (LS), maximum posteriori probability (MAP), linear minimum mean square error (LMMSE), and minimum mean square error (MMSE), are proposed. The performances of these estimators are compared with the derived Bayesian Cramer-Rao lower bound (BCRLB), which can be used as a benchmark to evaluate the efficiency of the unbiased estimators. The presented analytical results, corroborated with Monte Carlo simulations, indicate that the MMSE estimator provides the best results. Additionally, the increasing number of pilot symbols as well as the ascending transmitted power improve the system performance. On the other hand, the noise variance has a negative effect on the channel estimation in terms of mean square error (MSE), and thus, it can dramatically reduce the performance of the estimators.
Citation - WoS: 1
Citation - Scopus: 7
Impact of Channel Correlation and Hardware Impairments on Large Intelligent Surfaces-Aided Communication Systems
(Ieee, 2021) Saleh, Emad; Alsmadi, Malek M.; Bouhlel, Asma; Canbilen, Ayşe E.; Abu Ali, Najah; Ikki, Salama
Large Intelligent Surfaces (LIS) are promising in terms of what they can offer to 6G and beyond communication networks. As such, they have recently attracted considerable attention in the research community. This technique allows the operators to control the environment in a strategic way so as to improve the communication system performance. This work studies the effect of hardware impairments (HWIs) on the LIS-Aided wireless communication system under correlated channel conditions. In specific, we look at the impact on the system performance. We also give a deterministic approximation function of the average bit error rate (ABER) for a large number of reflectors and a tight approximation of the outage probability (OP). Extensive Monte Carlo simulations are provided to verify the analytical results, which show that the system performance saturates at a high signal-to-noise ratio (SNR) due to the HWIs. Moreover, this degradation is exacerbated when the channels demonstrate strong correlation conditions. However, the HWIs have a dominant effect and the correlation impact diminishes with a larger number of reflectors.