Adel Aldalbahi | King Faisal University (original) (raw)

Papers by Adel Aldalbahi

2019 International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob)

This paper presents an initial study on using diversity coding schemes for virtual network functi... more This paper presents an initial study on using diversity coding schemes for virtual network function (VNF) link and node failure recovery in 5G and beyond networks. In contrast to conventional link recovery methods, the proposed scheme offers near-instantaneous recovery times without retransmission requirements. Furthermore, the recovery scheme provides significant reduction in routing and capacity costs, at reduced number of redundant links and high number of traffic requests. Hence reliable recovery, node resiliency, reduced delays and ultra-low latency are achieved here. In addition, a mixed liner integer programming (MILP) optimization formulation model is also proposed for the VNF failure restoration.

Applied Sciences

Fog-radio access networks (F-RANs) alleviate fronthaul delays for cellular networks as compared t... more Fog-radio access networks (F-RANs) alleviate fronthaul delays for cellular networks as compared to their cloud counterparts. This allows them to be suitable solutions for networks that demand low propagation delays. Namely, they are suitable for millimeter wave (mmWave) operations that suffer from short propagation distances and possess a poor scattering environment (low channel ranks). The F-RAN here is comprised of fog nodes that are collocated with radio remote heads (RRHs) to provide local processing capabilities for mobile station (MS) terminals. These terminals demand various network functions (NFs) that correspond to different service requests. Now, provisioning these NFs on the fog nodes also yields service delays due to the requirement for service migration from the cloud, i.e., offloading to the fog nodes. One solution to reduce this service delay is to provide cached copies of popular NFs in advance. Hence, it is critical to study function popularity and allow for content...

2019 IEEE 9th Annual Computing and Communication Workshop and Conference (CCWC)

Millimeter Wave bands suffer from various channel impairments, such as path loss and blockage sen... more Millimeter Wave bands suffer from various channel impairments, such as path loss and blockage sensitivity. Hence, mmWave channels have widely been termed as sparse channels, composed of limited number of rays and clusters. Therefore, analog beamforming architectures become less practical due to its single beam transmission, which can result in link failure due to blockage effects. However, analog beamforming requires very efficient power and energy consumption levels, as compared to digital and hybrid solutions. Hence in this paper, a novel multi-beam analog beamforming transmission technique is proposed that increases the scattering intensity in mmWave sparse channels. This in return allows analog beamforming channels to be increasingly rich-scattering. Namely, grating lobes are deliberately generated for an analog beamformer to increase the scattering intensity in non-line of sight environments, and hence increasing the number of scattering (rays and clusters) in the received signal power delay profile. Simulation results show that channel intensity significantly increases when grating lobes are enabled at one-wavelength antenna spacing, as compared to half-wavelength spacing.

Applied Sciences

Millimeter wave (mmWave) bands formulate the standalone (SA) operation mode in the new radio (NR)... more Millimeter wave (mmWave) bands formulate the standalone (SA) operation mode in the new radio (NR) access technology of 5G systems. These bands rely on beamforming architectures to aggregate antenna array gains that compensate for dynamic channel fluctuations and propagation impairments. However, beamforming results in directional transmission and reception, thus resulting in beam management challenges, foremost initial access, handover, and beam blockage recovery. Here, beam establishment and maintenance must feature ultra-low latencies in the control and data planes to meet network specifications and standardization. Presently, existing schemes rely on arrays redundancy, multi-connectivity, such as dual-beam and carrier aggregation, and out-of-band information. These schemes still suffer from prolonged recovery times and aggregated power consumption levels. Along these lines, this work proposes a fast beam restoration scheme based on deep learning in SA mmWave networks. Once the pr...

IEEE Transactions on Engineering Management

2018 IEEE International Symposium on Signal Processing and Information Technology (ISSPIT), 2018

Millimeter Wave systems face significant challenges for robust signal transmission in the presenc... more Millimeter Wave systems face significant challenges for robust signal transmission in the presence of aggregated path loss and penetration losses. Namely, once the link between the mobile and base stations is successfully established, i.e., based upon initial access schemes that determine the optimum beamforming and combing vectors at which the optimum signal level is detected. However, the signal associated with the optimum link can rapidly degrade due to increased obstacles in the link of various densities and sizes. This yields in reduced signal levels and link failure, consequently resulting in communication loss during control- or user-planes. This paper presents efficient link recovery scheme based upon diversity coding for multi-beam transmissions to overcome blockage effects. The proposed scheme features near-instantaneous link recovery times without the need for repeated beam search over all spatial directions, as compared to traditional recovery schemes that perform exhaustive and iterative beam to determine the new optimum direction.

2021 IEEE Global Conference on Artificial Intelligence and Internet of Things (GCAIoT), 2021

IEEE Access, 2022

Machine learning algorithms represent the intelligence that controls many information systems and... more Machine learning algorithms represent the intelligence that controls many information systems and applications around us. As such, they are targeted by attackers to impact their decisions. Text created by machine learning algorithms has many types of applications, some of which can be considered malicious especially if there is an intention to present machine-generated text as human-generated. In this paper, we surveyed major subjects in adversarial machine learning for text processing applications. Unlike adversarial machine learning in images, text problems and applications are heterogeneous. Thus, each problem can have its own challenges. We focused on some of the evolving research areas such as: malicious versus genuine text generation metrics, defense against adversarial attacks, and text generation models and algorithms. Our study showed that as applications of text generation will continue to grow in the near future, the type and nature of attacks on those applications and their machine learning algorithms will continue to grow as well. Literature survey indicated an increasing trend in using pre-trained models in machine learning. Word/sentence embedding models and transformers are examples of those pre-trained models. Adversarial models may utilize same or similar pre-trained models as well. In another trend related to text generation models, literature showed effort to develop universal text perturbations to be used in both black-and whitebox attack settings. Literature showed also using conditional GANs to create latent representation for writing types. This usage will allow for a seamless lexical and grammatical transition between various writing styles. In text generation metrics, research trends showed developing successful automated or semi-automated assessment metrics that may include human judgement. Literature showed also research trends of designing and developing new memory models that increase performance and memory utilization efficiency without validating real-time constraints. Many research efforts evaluate different defense model approaches and algorithms. Researchers evaluated different types of targeted attacks, and methods to distinguish human versus machine generated text.

2018 14th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob), 2018

Cellular networks at millimeter wave frequencies experience tremendous propagation impairments an... more Cellular networks at millimeter wave frequencies experience tremendous propagation impairments and channel fluctuations. One major challenge here is the aggregated path loss levels attributed to obstacles of various shapes and density in the propagation links, i.e., link blockage. Therefore, once the base and mobile stations establish the optimum beamforming and combining vectors during the initial beam access procedure in the control-plane, efficient link maintenance techniques are required to maintain communication sessions with sufficient signal levels at various blockage densities. Hence this paper presents a novel link recovery scheme based upon beam aggregation during link transitions from line-of-sight to non-line-of-sight (NLoS) environments. The proposed scheme utilizes circular antenna arrays and hybrid beamforming designs to achieve near-instantaneous recovery times without the need for repeated beam scanning. Simulation results show that the proposed recovery scheme exhibits significant improvements compared to alternative traditional methods in terms of signal-to-noise ratios and recovery times.

IEEE Access, 2020

From recent research work, it has been shown that neural network (NN) classifiers are vulnerable ... more From recent research work, it has been shown that neural network (NN) classifiers are vulnerable to adversarial examples which contain special perturbations that are ignored by human eyes while can mislead NN classifiers. In this paper, we propose a practical black-box adversarial example generator, dubbed ManiGen. ManiGen does not require any knowledge of the inner state of the target classifier. It generates adversarial examples by searching along the manifold, which is a concise representation of input data. Through extensive set of experiments on different datasets, we show that (1) adversarial examples generated by ManiGen can mislead standalone classifiers by being as successful as the state-of-the-art whitebox generator, Carlini, and (2) adversarial examples generated by ManiGen can more effectively attack classifiers with state-of-the-art defenses. INDEX TERMS Adversarial examples, machine learning, neural network, manifold.

IEEE Access, 2021

The operation of unmanned aerial vehicles (UAV) imposes various challenges on radio spectrum mana... more The operation of unmanned aerial vehicles (UAV) imposes various challenges on radio spectrum management to achieve safe operation, efficient spectrum utilization, and coexistence with legacy wireless networks. Current spectrum schemes have limitations when applied to UAV networks due to the dynamic nature of UAV networks that require adaptive spectrum decisions and robust schemes that provide seamless and reliable services. Existing surveys mostly focus on UAV applications, channel models, and security challenges, with a lack of studies on spectrum management in the context of UAV networks. Further, current spectrum efforts focus on terrestrial networks that feature fixed infrastructure and less dynamicity as compared to UAV networks. This motivates the need to revisit existing approaches and identify suitable schemes that allow for the rapid integration of UAVs with existing wireless technologies. Motivated by this observation, this article presents a comprehensive survey on spectrum management for UAV operations. It identifies suitable management schemes that align with UAV features and requirements to enable safe and efficient usage of the radio spectrum. The article assumes coexistence with prevalent wireless technologies that occupy the spectrum. It first presents the ruling from policymakers and regulators and discusses operation bands and radio interfaces. It then introduces deployment scenarios (applications and architectures) as standalone or heterogeneous networks. This is followed by a systematic structure for the management tools that employ deterministic, opportunistic, and competitive schemes. In addition, network monitoring, patrolling, and enforcement schemes are identified. The survey also specifies key tools that can be leveraged for spectrum management solutions such as optimization and blockchain. Finally, it recognizes open research directions and challenges that need to be tackled to advance UAV communications.

2019 International Symposium on Networks, Computers and Communications (ISNCC), 2019

Routing protocols in wireless sensor network are vulnerable to various malicious security attacks... more Routing protocols in wireless sensor network are vulnerable to various malicious security attacks that can degrade network performance and lifetime. This becomes more important in cluster routing protocols that is composed of multiple node and cluster head, such as low energy adaptive clustering hierarchy (LEACH) protocol. Namely, if an attack succeeds in failing the cluster head, then the entire set of nodes fail. Therefore, it is necessary to develop robust recovery schemes to overcome security attacks and recover packets at short times. Hence this paper proposes a detection and recovery scheme for selective forwarding attacks in wireless sensor networks using LEACH protocol. The proposed solution features near-instantaneous recovery times, without the requirement for feedback or retransmissions once an attack occurs.

2017 IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), 2017

Millimeter wave channels suffer from large path losses, penetration losses and atmospheric attenu... more Millimeter wave channels suffer from large path losses, penetration losses and atmospheric attenuation. Although beamforming techniques can significantly enhance link margins here, they also introduce initial beam access problems at the base and mobile stations prior to data transmission. Hence this paper presents an effective access scheme inspired by the Hooke Jeeves direct pattern search for analog beamforming cascaded codebooks. Simulation results show that the proposed algorithm delivers substantial performance improvements versus existing solutions in terms of computational complexity, access times and power and energy consumption.

2019 SoutheastCon, 2019

Directional transmission in standalone millimeter wave networks provides aggregated gains that co... more Directional transmission in standalone millimeter wave networks provides aggregated gains that compensates for channel impairments and path losses. However, this saliency results in initial access and handover challenges. Namely, narrow beam transmission is vulnerable to link blockage, user mobility, sparse received power profile, increased latencies and power consumption. Hence, this paper presents a novel handover scheme that utilizes primary and redundant beams transmission at the mobile station. Here, the redundant beam is used in different modes based upon link state. Foremost, once blockage is introduced to the primary beam, then an instantaneous self-handover procedure is performed by the redundant beam to a new base station. This maintains communication sessions without the requirement for repeated beam search. Meanwhile, the redundant beam is aggregated with the primary beam for enhanced spectral efficiencies in the absence of blockage effects. The scheme deploys hybrid and digital beamforming architectures at the mobile station (MS) and base station (BS), respectively, i.e., using uninform circular arrays. The proposed scheme yields enhanced spectral efficiencies, high received power profiles, and near-instantaneous recovery times, as compared to conventional recovery schemes.

2019 2nd International Conference on Computer Applications & Information Security (ICCAIS), 2019

In this paper, the performance of Fast Orthogonal Frequency Division Multiplexing (FOFDM) over di... more In this paper, the performance of Fast Orthogonal Frequency Division Multiplexing (FOFDM) over dispersive Intensity Modulation (IM) and Direct Detection (DD) channel is evaluated using various modulation formats. The results obtained are compared with those from a similar system using OFDM modulation. At the same spectral efficiency, FOFDM proves to be more resilient to ISI and signal distortion, mainly at lower transmission distances.

2019 IEEE 10th Annual Ubiquitous Computing, Electronics & Mobile Communication Conference (UEMCON), 2019

Conventional initial beam access schemes for millimeter wave systems suffer from high computation... more Conventional initial beam access schemes for millimeter wave systems suffer from high computational complexity and prolonged access times. Hence this paper proposes an efficient beam access algorithm based upon simultaneous dual-beam codebook transmission and beam coding. The spatial search space is formulated as an optimization problem and a novel direct-pattern search is proposed here, i.e., the algorithm adapts the beam search by conquering the observed cluster profile. Simulation results show that the algorithm significantly overcomes major access methods.

Electronics, 2021

The use of beamforming technology in standalone (SA) millimeter wave communications results in di... more The use of beamforming technology in standalone (SA) millimeter wave communications results in directional transmission and reception modes at the mobile station (MS) and base station (BS). This results in initial beam access challenges, since the MS and BS are now compelled to perform spatial search to determine the best beam directions that return highest signal levels. The high number of signal measurements here prolongs access times and latencies, as well as increasing power and energy consumption. Hence this paper proposes a first study on leveraging deep learning schemes to simplify the beam access procedure in standalone mmWave networks. The proposed scheme combines bidirectional recurrent neural network (BRNN) and long short-term memory (LSTM) to achieve fast initial access times. Namely, the scheme predicts the best beam index for use in the next time step once a MS accesses the network, e.g., transition from sleep to active (or idle) modes. The scheme eliminates the need f...

IEEE Access, 2021

Millimeter wave communications technology is an essential component of the new radio (NR) standar... more Millimeter wave communications technology is an essential component of the new radio (NR) standard for standalone 5G networks, i.e., frequency range 2 (FR2) bands. This technology provides contiguous bandwidth at the detriment of high path loss and blockage sensitivity. Hence beamforming architectures are leveraged to compensate for the channel impairments. However, beamforming introduces significant challenges in terms of initial beam access and beam adaptation requirements. Namely, the base station (BS) and mobile station (MS) are compelled to search the entire spatial directions to specify the pointing directions (optimum beamforming and combining vectors) that yield in the strongest impinged signal levels. This search process results in a high computational complexity, extended delay periods, high power consumption and energy inefficiency. Hence this paper proposes a novel sector (beam) prediction scheme that leverages the synergistic combination of convolutional neural networks (CNN) and long shortterm memory (LSTM). The goal is to propose ultra-low access times for FR2-bsaed 5G networks, thus enhancing mmWave bands to operate independently as a standalone network without reliance on Frequency Range 1 (FR1) bands, e.g., dual-connectivity. The proposed scheme here predicts the primary sector with the highest popularity class at the BS, which is affiliated with the mostly used beamforming vector. This retrieves information about the sector locations with the highest MS traffic, thereby the BS can eliminate the spatial search over locations of scarce MS densities. Consequently, this process reduces the beam scanning search at the BS, while performing conventional search at the MS. The proposed scheme yields in reduced complexity and access times as compared to prominent existing methods. INDEX TERMS Beamforming, convolutional neural networks, deep learning, initial access, long short-term memory, millimeter wave communications, uniform planar array.

2019 2nd International Conference on Computer Applications & Information Security (ICCAIS), 2019

In this paper, the performance of different nonlinear electrical compensation techniques is evalu... more In this paper, the performance of different nonlinear electrical compensation techniques is evaluated. The goal is to enhance the transmission quality of intensity modulation (IM) and direct detection (DD) optical orthogonal frequency division multiplexing (OOFDM). The overall performance results are compared versus linear compensator equalizers. Also, studies here include the looking at the capability of Volterra based electrical equalizers for transmitted signal recovery.

Electronics, 2019

In this paper, a comprehensive design and simulation of an all-photonic XOR logic gate is propose... more In this paper, a comprehensive design and simulation of an all-photonic XOR logic gate is proposed. The design is based on the third-order Kerr nonlinear effect in highly nonlinear fiber, i.e., utilizing the self-phase and cross-phase modulations phenomena. This work presents the first photonic logic gate based on highly nonlinear fiber component only that achieves a data rate of 20 Gbps. Moreover, the design is based on two input binary bit sequences, narrow pulsed by a Gaussian distribution as 8-bit incoming data streams. Also, optical cross connectors with different coupling coefficients are used to generate pump and probe signals and tuneable optical band pass filters are leveraged to perform the logic gate functionalities. Remarkable performance outcomes are concluded from the eye pattern diagram and bit error rate analyzers. Simulation results show that the proposed XOR optical logic gate design is achieved at very low power penalties, low bit error rates, a significant Q-fact...

2019 International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob)

This paper presents an initial study on using diversity coding schemes for virtual network functi... more This paper presents an initial study on using diversity coding schemes for virtual network function (VNF) link and node failure recovery in 5G and beyond networks. In contrast to conventional link recovery methods, the proposed scheme offers near-instantaneous recovery times without retransmission requirements. Furthermore, the recovery scheme provides significant reduction in routing and capacity costs, at reduced number of redundant links and high number of traffic requests. Hence reliable recovery, node resiliency, reduced delays and ultra-low latency are achieved here. In addition, a mixed liner integer programming (MILP) optimization formulation model is also proposed for the VNF failure restoration.

Applied Sciences

Fog-radio access networks (F-RANs) alleviate fronthaul delays for cellular networks as compared t... more Fog-radio access networks (F-RANs) alleviate fronthaul delays for cellular networks as compared to their cloud counterparts. This allows them to be suitable solutions for networks that demand low propagation delays. Namely, they are suitable for millimeter wave (mmWave) operations that suffer from short propagation distances and possess a poor scattering environment (low channel ranks). The F-RAN here is comprised of fog nodes that are collocated with radio remote heads (RRHs) to provide local processing capabilities for mobile station (MS) terminals. These terminals demand various network functions (NFs) that correspond to different service requests. Now, provisioning these NFs on the fog nodes also yields service delays due to the requirement for service migration from the cloud, i.e., offloading to the fog nodes. One solution to reduce this service delay is to provide cached copies of popular NFs in advance. Hence, it is critical to study function popularity and allow for content...

2019 IEEE 9th Annual Computing and Communication Workshop and Conference (CCWC)

Millimeter Wave bands suffer from various channel impairments, such as path loss and blockage sen... more Millimeter Wave bands suffer from various channel impairments, such as path loss and blockage sensitivity. Hence, mmWave channels have widely been termed as sparse channels, composed of limited number of rays and clusters. Therefore, analog beamforming architectures become less practical due to its single beam transmission, which can result in link failure due to blockage effects. However, analog beamforming requires very efficient power and energy consumption levels, as compared to digital and hybrid solutions. Hence in this paper, a novel multi-beam analog beamforming transmission technique is proposed that increases the scattering intensity in mmWave sparse channels. This in return allows analog beamforming channels to be increasingly rich-scattering. Namely, grating lobes are deliberately generated for an analog beamformer to increase the scattering intensity in non-line of sight environments, and hence increasing the number of scattering (rays and clusters) in the received signal power delay profile. Simulation results show that channel intensity significantly increases when grating lobes are enabled at one-wavelength antenna spacing, as compared to half-wavelength spacing.

Applied Sciences

Millimeter wave (mmWave) bands formulate the standalone (SA) operation mode in the new radio (NR)... more Millimeter wave (mmWave) bands formulate the standalone (SA) operation mode in the new radio (NR) access technology of 5G systems. These bands rely on beamforming architectures to aggregate antenna array gains that compensate for dynamic channel fluctuations and propagation impairments. However, beamforming results in directional transmission and reception, thus resulting in beam management challenges, foremost initial access, handover, and beam blockage recovery. Here, beam establishment and maintenance must feature ultra-low latencies in the control and data planes to meet network specifications and standardization. Presently, existing schemes rely on arrays redundancy, multi-connectivity, such as dual-beam and carrier aggregation, and out-of-band information. These schemes still suffer from prolonged recovery times and aggregated power consumption levels. Along these lines, this work proposes a fast beam restoration scheme based on deep learning in SA mmWave networks. Once the pr...

IEEE Transactions on Engineering Management

2018 IEEE International Symposium on Signal Processing and Information Technology (ISSPIT), 2018

Millimeter Wave systems face significant challenges for robust signal transmission in the presenc... more Millimeter Wave systems face significant challenges for robust signal transmission in the presence of aggregated path loss and penetration losses. Namely, once the link between the mobile and base stations is successfully established, i.e., based upon initial access schemes that determine the optimum beamforming and combing vectors at which the optimum signal level is detected. However, the signal associated with the optimum link can rapidly degrade due to increased obstacles in the link of various densities and sizes. This yields in reduced signal levels and link failure, consequently resulting in communication loss during control- or user-planes. This paper presents efficient link recovery scheme based upon diversity coding for multi-beam transmissions to overcome blockage effects. The proposed scheme features near-instantaneous link recovery times without the need for repeated beam search over all spatial directions, as compared to traditional recovery schemes that perform exhaustive and iterative beam to determine the new optimum direction.

2021 IEEE Global Conference on Artificial Intelligence and Internet of Things (GCAIoT), 2021

IEEE Access, 2022

Machine learning algorithms represent the intelligence that controls many information systems and... more Machine learning algorithms represent the intelligence that controls many information systems and applications around us. As such, they are targeted by attackers to impact their decisions. Text created by machine learning algorithms has many types of applications, some of which can be considered malicious especially if there is an intention to present machine-generated text as human-generated. In this paper, we surveyed major subjects in adversarial machine learning for text processing applications. Unlike adversarial machine learning in images, text problems and applications are heterogeneous. Thus, each problem can have its own challenges. We focused on some of the evolving research areas such as: malicious versus genuine text generation metrics, defense against adversarial attacks, and text generation models and algorithms. Our study showed that as applications of text generation will continue to grow in the near future, the type and nature of attacks on those applications and their machine learning algorithms will continue to grow as well. Literature survey indicated an increasing trend in using pre-trained models in machine learning. Word/sentence embedding models and transformers are examples of those pre-trained models. Adversarial models may utilize same or similar pre-trained models as well. In another trend related to text generation models, literature showed effort to develop universal text perturbations to be used in both black-and whitebox attack settings. Literature showed also using conditional GANs to create latent representation for writing types. This usage will allow for a seamless lexical and grammatical transition between various writing styles. In text generation metrics, research trends showed developing successful automated or semi-automated assessment metrics that may include human judgement. Literature showed also research trends of designing and developing new memory models that increase performance and memory utilization efficiency without validating real-time constraints. Many research efforts evaluate different defense model approaches and algorithms. Researchers evaluated different types of targeted attacks, and methods to distinguish human versus machine generated text.

2018 14th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob), 2018

Cellular networks at millimeter wave frequencies experience tremendous propagation impairments an... more Cellular networks at millimeter wave frequencies experience tremendous propagation impairments and channel fluctuations. One major challenge here is the aggregated path loss levels attributed to obstacles of various shapes and density in the propagation links, i.e., link blockage. Therefore, once the base and mobile stations establish the optimum beamforming and combining vectors during the initial beam access procedure in the control-plane, efficient link maintenance techniques are required to maintain communication sessions with sufficient signal levels at various blockage densities. Hence this paper presents a novel link recovery scheme based upon beam aggregation during link transitions from line-of-sight to non-line-of-sight (NLoS) environments. The proposed scheme utilizes circular antenna arrays and hybrid beamforming designs to achieve near-instantaneous recovery times without the need for repeated beam scanning. Simulation results show that the proposed recovery scheme exhibits significant improvements compared to alternative traditional methods in terms of signal-to-noise ratios and recovery times.

IEEE Access, 2020

From recent research work, it has been shown that neural network (NN) classifiers are vulnerable ... more From recent research work, it has been shown that neural network (NN) classifiers are vulnerable to adversarial examples which contain special perturbations that are ignored by human eyes while can mislead NN classifiers. In this paper, we propose a practical black-box adversarial example generator, dubbed ManiGen. ManiGen does not require any knowledge of the inner state of the target classifier. It generates adversarial examples by searching along the manifold, which is a concise representation of input data. Through extensive set of experiments on different datasets, we show that (1) adversarial examples generated by ManiGen can mislead standalone classifiers by being as successful as the state-of-the-art whitebox generator, Carlini, and (2) adversarial examples generated by ManiGen can more effectively attack classifiers with state-of-the-art defenses. INDEX TERMS Adversarial examples, machine learning, neural network, manifold.

IEEE Access, 2021

The operation of unmanned aerial vehicles (UAV) imposes various challenges on radio spectrum mana... more The operation of unmanned aerial vehicles (UAV) imposes various challenges on radio spectrum management to achieve safe operation, efficient spectrum utilization, and coexistence with legacy wireless networks. Current spectrum schemes have limitations when applied to UAV networks due to the dynamic nature of UAV networks that require adaptive spectrum decisions and robust schemes that provide seamless and reliable services. Existing surveys mostly focus on UAV applications, channel models, and security challenges, with a lack of studies on spectrum management in the context of UAV networks. Further, current spectrum efforts focus on terrestrial networks that feature fixed infrastructure and less dynamicity as compared to UAV networks. This motivates the need to revisit existing approaches and identify suitable schemes that allow for the rapid integration of UAVs with existing wireless technologies. Motivated by this observation, this article presents a comprehensive survey on spectrum management for UAV operations. It identifies suitable management schemes that align with UAV features and requirements to enable safe and efficient usage of the radio spectrum. The article assumes coexistence with prevalent wireless technologies that occupy the spectrum. It first presents the ruling from policymakers and regulators and discusses operation bands and radio interfaces. It then introduces deployment scenarios (applications and architectures) as standalone or heterogeneous networks. This is followed by a systematic structure for the management tools that employ deterministic, opportunistic, and competitive schemes. In addition, network monitoring, patrolling, and enforcement schemes are identified. The survey also specifies key tools that can be leveraged for spectrum management solutions such as optimization and blockchain. Finally, it recognizes open research directions and challenges that need to be tackled to advance UAV communications.

2019 International Symposium on Networks, Computers and Communications (ISNCC), 2019

Routing protocols in wireless sensor network are vulnerable to various malicious security attacks... more Routing protocols in wireless sensor network are vulnerable to various malicious security attacks that can degrade network performance and lifetime. This becomes more important in cluster routing protocols that is composed of multiple node and cluster head, such as low energy adaptive clustering hierarchy (LEACH) protocol. Namely, if an attack succeeds in failing the cluster head, then the entire set of nodes fail. Therefore, it is necessary to develop robust recovery schemes to overcome security attacks and recover packets at short times. Hence this paper proposes a detection and recovery scheme for selective forwarding attacks in wireless sensor networks using LEACH protocol. The proposed solution features near-instantaneous recovery times, without the requirement for feedback or retransmissions once an attack occurs.

2017 IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), 2017

Millimeter wave channels suffer from large path losses, penetration losses and atmospheric attenu... more Millimeter wave channels suffer from large path losses, penetration losses and atmospheric attenuation. Although beamforming techniques can significantly enhance link margins here, they also introduce initial beam access problems at the base and mobile stations prior to data transmission. Hence this paper presents an effective access scheme inspired by the Hooke Jeeves direct pattern search for analog beamforming cascaded codebooks. Simulation results show that the proposed algorithm delivers substantial performance improvements versus existing solutions in terms of computational complexity, access times and power and energy consumption.

2019 SoutheastCon, 2019

Directional transmission in standalone millimeter wave networks provides aggregated gains that co... more Directional transmission in standalone millimeter wave networks provides aggregated gains that compensates for channel impairments and path losses. However, this saliency results in initial access and handover challenges. Namely, narrow beam transmission is vulnerable to link blockage, user mobility, sparse received power profile, increased latencies and power consumption. Hence, this paper presents a novel handover scheme that utilizes primary and redundant beams transmission at the mobile station. Here, the redundant beam is used in different modes based upon link state. Foremost, once blockage is introduced to the primary beam, then an instantaneous self-handover procedure is performed by the redundant beam to a new base station. This maintains communication sessions without the requirement for repeated beam search. Meanwhile, the redundant beam is aggregated with the primary beam for enhanced spectral efficiencies in the absence of blockage effects. The scheme deploys hybrid and digital beamforming architectures at the mobile station (MS) and base station (BS), respectively, i.e., using uninform circular arrays. The proposed scheme yields enhanced spectral efficiencies, high received power profiles, and near-instantaneous recovery times, as compared to conventional recovery schemes.

2019 2nd International Conference on Computer Applications & Information Security (ICCAIS), 2019

In this paper, the performance of Fast Orthogonal Frequency Division Multiplexing (FOFDM) over di... more In this paper, the performance of Fast Orthogonal Frequency Division Multiplexing (FOFDM) over dispersive Intensity Modulation (IM) and Direct Detection (DD) channel is evaluated using various modulation formats. The results obtained are compared with those from a similar system using OFDM modulation. At the same spectral efficiency, FOFDM proves to be more resilient to ISI and signal distortion, mainly at lower transmission distances.

2019 IEEE 10th Annual Ubiquitous Computing, Electronics & Mobile Communication Conference (UEMCON), 2019

Conventional initial beam access schemes for millimeter wave systems suffer from high computation... more Conventional initial beam access schemes for millimeter wave systems suffer from high computational complexity and prolonged access times. Hence this paper proposes an efficient beam access algorithm based upon simultaneous dual-beam codebook transmission and beam coding. The spatial search space is formulated as an optimization problem and a novel direct-pattern search is proposed here, i.e., the algorithm adapts the beam search by conquering the observed cluster profile. Simulation results show that the algorithm significantly overcomes major access methods.

Electronics, 2021

The use of beamforming technology in standalone (SA) millimeter wave communications results in di... more The use of beamforming technology in standalone (SA) millimeter wave communications results in directional transmission and reception modes at the mobile station (MS) and base station (BS). This results in initial beam access challenges, since the MS and BS are now compelled to perform spatial search to determine the best beam directions that return highest signal levels. The high number of signal measurements here prolongs access times and latencies, as well as increasing power and energy consumption. Hence this paper proposes a first study on leveraging deep learning schemes to simplify the beam access procedure in standalone mmWave networks. The proposed scheme combines bidirectional recurrent neural network (BRNN) and long short-term memory (LSTM) to achieve fast initial access times. Namely, the scheme predicts the best beam index for use in the next time step once a MS accesses the network, e.g., transition from sleep to active (or idle) modes. The scheme eliminates the need f...

IEEE Access, 2021

Millimeter wave communications technology is an essential component of the new radio (NR) standar... more Millimeter wave communications technology is an essential component of the new radio (NR) standard for standalone 5G networks, i.e., frequency range 2 (FR2) bands. This technology provides contiguous bandwidth at the detriment of high path loss and blockage sensitivity. Hence beamforming architectures are leveraged to compensate for the channel impairments. However, beamforming introduces significant challenges in terms of initial beam access and beam adaptation requirements. Namely, the base station (BS) and mobile station (MS) are compelled to search the entire spatial directions to specify the pointing directions (optimum beamforming and combining vectors) that yield in the strongest impinged signal levels. This search process results in a high computational complexity, extended delay periods, high power consumption and energy inefficiency. Hence this paper proposes a novel sector (beam) prediction scheme that leverages the synergistic combination of convolutional neural networks (CNN) and long shortterm memory (LSTM). The goal is to propose ultra-low access times for FR2-bsaed 5G networks, thus enhancing mmWave bands to operate independently as a standalone network without reliance on Frequency Range 1 (FR1) bands, e.g., dual-connectivity. The proposed scheme here predicts the primary sector with the highest popularity class at the BS, which is affiliated with the mostly used beamforming vector. This retrieves information about the sector locations with the highest MS traffic, thereby the BS can eliminate the spatial search over locations of scarce MS densities. Consequently, this process reduces the beam scanning search at the BS, while performing conventional search at the MS. The proposed scheme yields in reduced complexity and access times as compared to prominent existing methods. INDEX TERMS Beamforming, convolutional neural networks, deep learning, initial access, long short-term memory, millimeter wave communications, uniform planar array.

2019 2nd International Conference on Computer Applications & Information Security (ICCAIS), 2019

In this paper, the performance of different nonlinear electrical compensation techniques is evalu... more In this paper, the performance of different nonlinear electrical compensation techniques is evaluated. The goal is to enhance the transmission quality of intensity modulation (IM) and direct detection (DD) optical orthogonal frequency division multiplexing (OOFDM). The overall performance results are compared versus linear compensator equalizers. Also, studies here include the looking at the capability of Volterra based electrical equalizers for transmitted signal recovery.

Electronics, 2019

In this paper, a comprehensive design and simulation of an all-photonic XOR logic gate is propose... more In this paper, a comprehensive design and simulation of an all-photonic XOR logic gate is proposed. The design is based on the third-order Kerr nonlinear effect in highly nonlinear fiber, i.e., utilizing the self-phase and cross-phase modulations phenomena. This work presents the first photonic logic gate based on highly nonlinear fiber component only that achieves a data rate of 20 Gbps. Moreover, the design is based on two input binary bit sequences, narrow pulsed by a Gaussian distribution as 8-bit incoming data streams. Also, optical cross connectors with different coupling coefficients are used to generate pump and probe signals and tuneable optical band pass filters are leveraged to perform the logic gate functionalities. Remarkable performance outcomes are concluded from the eye pattern diagram and bit error rate analyzers. Simulation results show that the proposed XOR optical logic gate design is achieved at very low power penalties, low bit error rates, a significant Q-fact...