Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/11
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Conference Object Carrier Frequency Offset Based Shared Randomness for Secure Transmission in M-Psk Noma(IEEE, 2023) Göztepe, Caner; Karabulut Kurt, Güneş; Özbek, BernaPower domain non-orthogonal multiple access (NOMA) enhances spectral efficiency by superposing multiple users in the same time-frequency resource block at the expense of exposing the users' data. However, current approaches to improve the secrecy levels of users are limited to rate reduction. This paper proposes a secure NOMA system based on the shared randomness extracted from the reciprocal carrier frequency offsets (CFOs) between the transmitter-receiver pairs for M-ary phase-shift keying. As multiple users will have physically separated oscillators, it will result in independent CFOs among users. This randomness is used to introduce a constellation rotation in the transmitted symbols. We show that under ideal CFO estimates, the proposed approach achieves perfect secrecy among all NOMA users without introducing any rate reduction. We also demonstrate the practical applicability of the proposed approach by using a software-defined radio-based test bed. © 2023 IEEE.Conference Object Citation - WoS: 1Citation - Scopus: 3Hybrid Beamforming for Secure Multiuser Mmwave Mimo Communications(Institute of Electrical and Electronics Engineers, 2020) Erdoğan, Oğulcan; Özbek, Berna; Busari, Sherif Adeshina; González, JonathanSecure communication is critical in wireless networks as the networks are prone to eavesdropping from unintended nodes. To address this challenge, physical layer security (PLS) is being employed to combat information leakage. In this paper, we present the performance evaluations based on the secrecy rate and the secrecy outage probability for multiuser multiple-input multiple-output (MIMO) millimeter-wave (mmWave) communications by employing hybrid beamforming (HBF) at the base station, legitimate users and eavesdropper. Using a 3-dimensional mmWave channel model and uniform planar antenna arrays (UPA), we employ artificial noise (AN) beamforming to jam the channels of eavesdropper and to enhance the secrecy rate. The transmitter uses the minimum mean square error (MMSE) precoder to mitigate multiuser interference for the secure MIMO mmWave systems. It is shown that the overall system performance highly depends on the power allocation factor between AN and the signal of legitimate users. © 2020 IEEE.Conference Object Citation - WoS: 3Citation - Scopus: 3Space-Frequency Grouping Based Key Extraction for Mimo-Ofdm Systems(IEEE, 2017) Topal, Ozan Alp; Karabulut Kurt, Güneş; Özbek, BernaLatest developments in wireless communication networks push the limits of conventional security methods. Security can be improved with a secret key that is dynamically generated based on the surrounding physical environment. With this objective, physical layer security approaches can be implemented by means of simple signal processing methods. In this paper, we propose novel key extraction approaches based on spatial and frequency characteristics of the wireless environment. In a 2x2 MIMO-OFDM system, low key disagreement rates and key error rates are observed, proving the potential of physical layer key extraction techniques.