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RISS 인기검색어
- 검색키워드
- 저자 : Saleh Al-Araji (검색결과 5 건)
- 무료
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Measurements and Analysis of Fingerprinting Structures for WLAN Localization Systems
Nuha Al Khanbash,Nayef Al Sindi,Nazar Ali,Saleh Al-Araji 한국전자통신연구원 2016 ETRI Journal Vol.38 No.4
Channel-based radio-frequency fingerprinting such as a channel impulse response (CIR), channel transfer function (CTF), and frequency coherence function (FCF) have been recently proposed to improve the accuracy at the physical layer; however, their empirical performance, advantages, and limitations have not been well reported. This paper provides a comprehensive empirical performance evaluation of RF location fingerprinting, focusing on a comparison of received-signal strength, CIR-, CTF-, and FCF-based fingerprinting using the weighted k-nearest neighbor pattern recognition technique. Frequency domain channel measurements in the IEEE 802.11 band taken on a university campus were used to evaluate the accuracy of the fingerprinting types and their robustness to human-induced motion perturbations of the channel. The localization performance was analyzed, and the results are described using the spatial and temporal radio propagation characteristics. In particular, we introduce the coherence region to explain the spatial properties and investigate the impact of the Doppler spread in time-varying channels on the time coherence of RF fingerprint structures.
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Novel Approach for Modeling Wireless Fading Channels Using a Finite State Markov Chain
Ahmed Abdul Salam,Ray Sheriff,Saleh Al-Araji,Kahtan Mezher,Qassim Nasir 한국전자통신연구원 2017 ETRI Journal Vol.39 No.5
Empirical modeling of wireless fading channels using common schemes such as autoregression and the finite state Markov chain (FSMC) is investigated. The conceptual background of both channel structures and the establishment of their mutual dependence in a confined manner are presented. The novel contribution lies in the proposal of a new approach for deriving the state transition probabilities borrowed from economic disciplines, which has not been studied so far with respect to the modeling of FSMC wireless fading channels. The proposed approach is based on equal portioning of the received signal-to-noise ratio, realized by using an alternative probability construction that was initially highlighted by Tauchen. The associated statistical procedure shows that a first-order FSMC with a limited number of channel states can satisfactorily approximate fading. The computational overheads of the proposed technique are analyzed and proven to be less demanding compared to the conventional FSMC approach based on the level crossing rate. Simulations confirm the analytical results and promising performance of the new channel model based on the Tauchen approach without extra complexity costs.
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Adaptive threshold and optimal frame duration for multi-taper spectrum sensing in cognitive radio
Ahmed O. Abdul Salam,Ray E. Sheriff,Saleh R. Al-Araji,Kahtan Mezher,Qassim Nasir 한국통신학회 2019 ICT Express Vol.5 No.1
This paper delivers an accurate approximation for adaptive threshold and optimal frame detection algorithms based on the robust multi-taper method aiming at an efficient spectrum sensing in cognitive radio systems. An appropriate adaptive thresholding allows for seamless vacation of unlicensed secondary users from certain bands upon primary users’ requests, while arbitrary optimal frame detection contributes to the computational and throughput demands. Simulation exercises corroborate the given analysis over Rayleigh channel and multiple-input multiple-output configuration and emphasize the critical role of adopting applicable adaptive threshold and optimal frame detection policies.
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Joint Design of Precoder and Backhaul Quantizer in Cooperative Cognitive Radio Networks
Lee, Seongmin,Kang, Jinkyu,Jeong, Seongah,Kang, Joonhyuk,Al-Araji, Saleh IEEE 2017 IEEE Transactions on Vehicular Technology VT Vol.66 No.2
<P>In cooperative cognitive radio networks (CRNs), multiple secondary base stations are managed by a central unit (CU) via finite-capacity backhaul links, which performs joint encoding and precoding of the messages intended for the secondary users (SUs). In this paper, the limitation of backhaul links is handled with the implementation of compression strategies, by which precoding is followed at the CU. In particular, focusing on underlay cooperative CRNs, we propose the joint optimal design of precoding and backhaul quantization with the aim of maximizing the sum throughput of the secondary network under limited backhaul capacity, transmit power, and interference power constraints. Furthermore, both perfect and imperfect channel state information (CSI) available at the CU are considered. In the imperfect-CSI case, the uncertainty of the channels is explicitly accounted for via a robust or worst-case optimization formulation. The proposed algorithmic solutions leverage rank relaxation and majorization-minimization programming, whose performances are evaluated via numerical results.</P>
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