Vol. 77, n° 3-4, March-April 2022
Content available on Springerlink

Lattice-based undeniable signature scheme

Swati Rawal¹, Sahadeo Padhye¹, Debiao He²
(1) Department of Mathematics, Motilal Nehru National Institute of Technology Allahabad, Prayagraj, India
(2) School of Cyber Science and Engineering, Wuhan University, Wuhan, China

Abstract In this paper, we propose a lattice-based undeniable signature where security is based on the hardness of the ISIS problem. The security requirements for an undeniable signature scheme are clearly described, and the proposed scheme is proved to enjoy completeness, soundness, unforgeability, and invisibility properties.

Keywords  Lattice-based cryptography · Digital signature · Undeniable signature · ISIS problem

Secrecy sum rate maximization for UAV-aided NOMA communication systems

Tuan Van Phu¹, Hyung Yun Kong²
(1) Department of Information & Communication Engineering, Kongju National University, Cheonan, South Korea
(2) Department of Electrical Engineering, University of Ulsan, Ulsan, South Korea

Abstract This article studies the secure communication of a non-orthogonal multiple access (NOMA) system with the help of an unmanned aerial vehicle (UAV). The UAV flies from an initial location to a final location and assists the NOMA communication between terrestrial nodes, including a source, a near user, and a far user, in the presence of an eavesdropper. Artificial noise (AN) is inserted into the transmitted signal of the UAV to enable secure communication for the users. To maximize the system secrecy sum-rate (SSSR), an algorithm is proposed to optimize key system parameters, such as the UAV’s trajectory, the power–allocation factors, and the transmit powers of the source and the UAV. Since the objective function of the SSSR maximization problem is non-convex, the successive convex optimization (SCO) and block coordinate descent (BCD) methods are applied to find efficient approximate solutions. The effectiveness of the proposed algorithms is confirmed by simulation results.

Keywords  Wireless networks · Unmanned aerial vehicles · Secrecy performance optimization · NOMA · Physical layer security

An SDN-based energy-aware traffic management mechanism

Alex B. Vieira¹, Wallace Nascimento Paraizo¹, Luciano Jerez Chaves¹, Luiz H. A. Correia², Edelberto Franco Silva¹
(1) Computer Science Department, Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil
(2) Computer Science Department, Universidade Federal de Lavras, Lavras, Brazil

Abstract Green computing is a central theme in many computer science areas, including computer networks. Dynamic solutions that can properly adjust network resources can prevent infrastructure over-provision and mitigate power consumption during low-demand periods. In this work, we propose DTM (Dynamic mechanism for Traffic Management), an energy-aware dynamic mechanism for traffic management, built upon the SDN paradigm. DTM continuously monitors the use of network links to concentrate traffic and disconnect idle equipment without degrading the offered quality of service. Our simulations show that the mechanism can save up to 46% of energy, on average, in the links’ capacities of homogeneous and heterogeneous scenarios. In scenarios with average to high traffic demands, the mean energy savings are 36.72% and 17.86%, respectively. Compared to a well-known existing mechanism, our approach is up to 7% better for medium-demand scenarios, and approximately 4% better for high-demand scenarios.

Keywords  Green computing · Power consumption · Software-defined networking · Traffic management

Product of two GaussianQ-functions as sum of exponentials and its applications

Supriya Aggarwal¹
(1) Department of Electronics and Communication Engineering, MANIT, Bhopal, India

Abstract In this paper, product of two Gaussian-Q functions is represented as sum of exponentials. It is further used to evaluate error probabilities of modulation techniques in fading distributions. The knowledge of moment generating function (MGF) is sufficient enough to derive closed-form solution to integrals appearing in symbol error probability (SEP). Numerical results demonstrate accuracy improvement over other existing competing approximations. Furthermore, the proposed solutions are fairly simple as MGF of fading models comprises of fundamental mathematical functions.

Keywords  AWGN · Symbol error probability · Fading distributions · Modulation techniques

Wi-Sense: a passive human activity recognition system using Wi-Fi
and convolutional neural network and its integration in health
information systems

Muhammad Muaaz¹, Ali Chelli¹, Martin Wulf Gerdes¹, Matthias Pätzold¹
(1) Faculty of Engineering and Science, University of Agder, Grimstad, Norway

Abstract A human activity recognition (HAR) system acts as the backbone of many human-centric applications, such as active assisted living and in-home monitoring for elderly and physically impaired people. Although existing Wi-Fi-based human activity recognition methods report good results, their performance is affected by the changes in the ambient environment. In this work, we present Wi-Sense—a human activity recognition system that uses a convolutional neural network (CNN) to recognize human activities based on the environment-independent fingerprints extracted from the Wi-Fi channel state information (CSI). First, Wi-Sense captures the CSI by using a standard Wi-Fi network interface card. Wi-Sense applies the CSI ratio method to reduce the noise and the impact of the phase offset. In addition, it applies the principal component analysis to remove redundant information. This step not only reduces the data dimension but also removes the environmental impact. Thereafter, we compute the processed data spectrogram which reveals environment-independent time-variant micro-Doppler fingerprints of the performed activity. We use these spectrogram images to train a CNN. We evaluate our approach by using a human activity data set collected from nine volunteers in an indoor environment. Our results show that Wi-Sense can recognize these activities with an overall accuracy of 97.78%. To stress on the applicability of the proposed Wi-Sense system, we provide an overview of the standards involved in the health information systems and systematically describe how Wi-Sense HAR system can be integrated into the eHealth infrastructure.

Keywords  Channel state information · Convolutional neural network · Doppler effect · Health information systems ·
Human activity recognition · Principal component analysis · Radio frequency sensing · Spectrogram

Iterative interference alignment with spatial hole sensing in MIMO
cognitive radio networks

Mustafa Namdar¹, Arif Basgumus¹, Sultan Aldirmaz-Colak², Eylem Erdogan³, Hakan Alakoca⁴, Seda Ustunbas⁵,
Lutfiye Durak-Ata⁴
(1) Department of Electrical and Electronics Engineering, Kutahya Dumlupinar University, Kutahya, Turkey
(2) Department of Electronics and Communications Engineering, Kocaeli University, Kocaeli, Turkey
(3) Department of Electrical and Electronics Engineering, Istanbul Medeniyet University, Istanbul, Turkey
(4) Informatics Institute, Istanbul Technical University, Istanbul, Turkey
(5) Department of Electronics and Communications Engineering, Istanbul Technical University, Istanbul, Turkey

Abstract This paper investigates the performance of iterative interference alignment (IA) with spatial hole sensing in K-user multi-input multi-output (MIMO) cognitive radio (CR) networks. In the considered network, there are some unused degrees of freedom (DoF) or equivalently spatial holes in the primary network (PN) where the secondary network (SN) users communicate without causing harmful interference to the PN receivers. First, the generalized likelihood ratio test method is utilized to determine the availability of the unused DoFs; then, it is decided whether individual primary streams are present in the PN. With the aid of precoding and suppression matrices generated by an iterative IA approach, the interferences in the PN that are caused by the SN are aligned, and due to the secondary transmission, interference leakage on the k^th primary receiver decreases below 10^− 6. The effects of the detection threshold values and the number of transmitter and receiver antennas are investigated in terms of detection and false alarm probability. Finally, the amplify-and-forward (AF) relaying scheme in the SN is evaluated and the impact of the relaying architecture on the system performance is analyzed.

Keywords  Amplify-and-forward relaying · Cognitive radio · Detection and false alarm probability · Iterative interference alignment
· Spatial hole sensing

Performance analysis of full-duplex decode-and-forward two-way
relay networks with transceiver impairments

Ba Cao Nguyen^1,2 · Xuan Nam Tran¹ · Dinh Tan Tran²
(1) Le Quy Don Technical University, Hanoi, Vietnam
(2) Telecommunications University, Khanh Hoa, Vietnam

Abstract In this paper, we analyze the performance of an in-band full-duplex (IBFD) decode-and-forward (DF) two-way relay (TWR) system whose two terminal nodes exchange information via a relay node over the same frequency and time slot. Unlike the previous works on full-duplex two-way relay systems, we investigate the system performance under the impacts of both hardware impairments and imperfect self-interference cancellation (SIC) at all full-duplex nodes. Specifically, we derive the exact expression of outage probability based on the signal to interference plus noise and distortion ratio (SINDR), thereby determine the throughput and the symbol error probability (SEP) of the considered system. The numerical results show a strong impact of transceiver impairments on the system performance, making it saturate at even a low level of residual self-interference. In order to tackle with the impact of hardware impairments, we derive an optimal power allocation factor for the relay node to minimize the outage performance. Finally, the numerical results are validated by Monte Carlo simulations.

Keywords  Full-duplex two-way relay · Self-interference cancellation · Decode-and-forward · Outage probability · Symbol error probability
· Hardware impairments

Federated learning-based scheme for detecting passive mobile attackers in 5G vehicular edge computing

Abdelwahab Boualouache¹, Thomas Engel¹
(1) Faculty of Science, Technology, and Medicine (FSTM), University of Luxembourg, Esch-sur-Alzette, Luxembourg

Abstract Detecting passive attacks is always considered difficult in vehicular networks. Passive attackers can eavesdrop on the wireless medium to collect beacons. These beacons can be exploited to track the positions of vehicles not only to violate their location privacy but also for criminal purposes. In this paper, we propose a novel federated learning-based scheme for detecting passive mobile attackers in 5G vehicular edge computing. We first identify a set of strategies that can be used by attackers to efficiently track vehicles without being visually detected. We then build an efficient machine learning (ML) model to detect tracking attacks based only on the receiving beacons. Our scheme enables federated learning (FL) at the edge to ensure collaborative learning while preserving the privacy of vehicles. Moreover, FL clients use a semi-supervised learning approach to ensure accurate self-labeling. Our experiments demonstrate the effectiveness of our proposed scheme to detect passive mobile attackers quickly and with high accuracy. Indeed, only 20 received beacons are required to achieve 95% accuracy. This accuracy can be achieved within 60 FL rounds using 5 FL clients in each FL round. The obtained results are also validated through simulations.

Keywords  5G vehicular edge computing · Machine learning · Federated learning · Security · Privacy · Passive attacker detection

A novel offline indoor acoustic synchronization protocol: experimental
analysis

Zahi Nakad¹, Mohammad Ali Sayed¹, Anthony Yaghi¹, Harag Margossian¹, Wissam Fawaz¹
(1) Lebanese American University, Byblos, Lebanon

Abstract Smart electronic devices are playing a fundamental role in modern home and industrial applications. The increased reliance on such devices, especially in time critical and secure applications, intensifies the need for time synchronization among multiple devices. This work presents a novel audio-based, cheap, offline synchronization method, whereby multiple slaves synchronize simultaneously to a master within a single room. Synchronization is carried out under the proposed protocol in a way that is independent of the physical location of the target devices, which in turn are not required to have any sort of network connectivity. The proposed method relies on the transmission of a De Bruijn sequence that holds the information required for the slaves to synchronize. The effectiveness of the proposed synchronization protocol is validated through an in-house experimental setup. Synchronization at distances of up to 250 cm between the master and a slave was achieved.

Keywords  Audio signals · De Bruijn sequence · Synchronization

A noise reduction orthogonal multi-user CDSK communication system based on frequency domain processing

Gang Zhang¹, Jiangtao Dong¹, Lifang He¹
(1) School of Communication and Information Engineering, Chongqing University of Posts and Telecommunications, Chongqing, China

Abstract In this paper, a noise reduction orthogonal multi-user correlated delay shift keying (NR-OMU-CDSK) noncoherent communication system based on frequency domain processing is proposed. In NR-OMU-CDSK, chaotic signal generated in frequency domain is converted to time domain through inverse Fourier transform, and then the real and imaginary components of the time domain signal are simultaneously modulated to two phase-orthogonal branches. The transmission rate and security performance of each branch are further improved by switches and Walsh code. In the receiver, moving average filter is used to reduce the variance of interference term in the decision variable, and information bits are obtained through relevant demodulation. The bit error rate (BER) performance of NR-OMU-CDSK is evaluated in AWGN channel and multipath Rayleigh fading channel. The research results show that the theoretical BER is basically consistent with the simulation results. The transmission rate of NR-OMU-CDSK is improved by 4N×100% (N is the number of users), and the signal-to-noise ratio is improved by nearly 4dB for the same BER performance, when NR-OMU-CDSK is compared with conventional CDSK in AWGN channel. Moreover, compared to other multi-user systems, this system has also obvious advantages in various system performance and avoids RF delay line problems.

Keywords  Chaotic communication system . Frequency domain processing . Orthogonal multi-user . Noise reduction
. Quadrature modulation