Yazar "Qaraqe, Khalid A." seçeneğine göre listele

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    Beam selection for ambient backscatter communication in beamspace mmWave symbiotic radio
    (Institute of Electrical and Electronics Engineers Inc., 2023) Janjua, Muhammad Bilal; Abbas, Hasan Tahir; Qaraqe, Khalid A.; Arslan, Hüseyin
    The Internet of Things revolution has profoundly impacted wireless communication systems. Access to high data rates is now just as important as low power operation. The use of incident millimeter-wave (mmWave) signals for ambient backscatter communication (AmBC) has shown significant promise for delivering high data rates. However, due to channel sparsity, incident signal availability to backscatter devices (BDs) at mmWave is erratic. In order to address the incident signal inaccessibility problem and enable high data-rate AmBC, this letter presents an efficient beam selection method in the beamspace millimeter-wave symbiotic radio system. The proposed method improves the overall system's sum-rate performance by up to 30% while ensuring signal accessibility to BDs.
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    On the performance of subcarrier allocation techniques for multiuser OFDM cognitive networks with reconfigurable antennas
    (Institute of Electrical and Electronics Engineers Inc., 2014) Yılmaz, Mustafa Harun; Abdallah, Mohamed M.; Qaraqe, Khalid A.; Arslan, Hüseyin
    Reconfigurable antennas (RA) have been viewed as a hardware-efficient alternative solution to multiple-input multiple-output systems whereby network users can vary the antenna radiation patterns using a single antenna element to maximize the received signal strength. In this paper, we study the potential benefits of employing RA in multiuser orthogonal frequency division multiple access cognitive heterogeneous networks (Het-Nets) in terms of the overall network capacity. In cognitive HetNets, a secondary (unlicensed) network is allowed to share the spectrum with the primary (licensed) network under the condition that the interference level at the primary network is below a predetermined value. To account for this interference constraint, the secondary user (SU) can limit their transmission power and thus reducing substantially its performance. Moreover, the large number of users expected for next generation network brings dense interference to the secondary network and thus even efficient interference mitigation and resource allocation techniques can fail in maintaining the required performance level. Therefore, in this paper, we consider utilizing an RA at the SUs that acts as an additional resource which can be optimized by selecting the best state that maximizes the signal strength among the SUs and limits the mutual interference between the secondary and primary network. In particular, we propose a game theoretical framework for selecting the subcarriers based on best allocation techniques as well as the random antenna state selection that maximizes the overall capacity of the network while obeying the interference level in the primary network. We use potential games which guarantee the Nash equilibrium existence. Our results show that by selecting the optimal RA state and the subcarriers for each user, the capacity of the secondary network increases substitutionally with limited hardware complexity.
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    Secure pilot allocation for integrated sensing and communication
    (Institute of Electrical and Electronics Engineers Inc., 2022) Janjua, Muhammad Bilal; Memisoglu, Ebubekir; Qaraqe, Khalid A.; Arslan, Hüseyin
    Sensing and physical layer security are among the key features of sixth-generation wireless networks. New security issues are emerging due to the proliferation of integrated sensing and communication applications, particularly in human activity monitoring and environment imaging. One way to achieve sensing is utilizing the communication signals' channel state information (CSI), namely CSI-based sensing. A malicious node with access to pilot information can obtain CSI and perform sensing to get vital information about a target. Therefore, the pilot information must be secured to prevent the acquisition of CSI by a malicious node for secure sensing and communication. This paper proposes a secure pilot allocation method to conceal the pilot location information from malicious nodes while securing communication and sensing data. Additionally, an adaptive power allocation method is provided to overcome the performance deterioration that occurs during the receiver's pilot location detection. Finally, the proposed algorithms' performance gains are investigated, and insightful conclusions are drawn.
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    Spatially distributed channel shortening aided physical layer security
    (Institute of Electrical and Electronics Engineers Inc., 2023) Solaija, Muhammad Sohaib J.; Salman, Hanadi; Qaraqe, Khalid A.; Arslan, Hüseyin
    Wireless networks have become imperative in all areas of human life. As such, one of the most critical concerns in next-generation networks is ensuring the security and privacy of user data/communication. Cryptography has been conventionally used to tackle this, but it may not be scalable (in terms of key exchange and management) with the increasingly heterogeneous network deployments. Physical layer security (PLS) provides a promising alternative but struggles when an attacker boasts a better wireless channel as compared to the legitimate user. In this work, a spatially distributed channel shortening approach is leveraged to address this problem. Specifically, the user data is split into multiple parts, where each part is sent using a different transmission point. This ensures that at least one of the illegitimate links experiences worse propagation channel as compared to the legitimate one. Additionally, a channel shortening filter is applied w.r.t legitimate links, which results in inter-symbol interference being introduced at the receiver. Results show significant enhancement of the achievable secrecy capacity as compared to state-of-the-art channel shortening-based PLS methods.