Mohamed Elalem
@elmergib.edu.ly
Electrical and Computer Engineering
Elmergib University
EDUCATION
PhD in Electrical and Computer Engineering, Ryerson University, Toronto, Canada
RESEARCH, TEACHING, or OTHER INTERESTS
Communication, Electrical and Electronic Engineering
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Mohamed Elalem and Tahani Jabir
IEEE
Cyber security in wireless communications can be an unwieldy subject, given the amount of malware that has been increasing rapidly in the last few years. This generates serious security problems for public agencies and the government institutions. In order to mitigate the influence of malware deployment and pervasiveness, new recent identification and classification algorithms for malware that adapt deep learning techniques are studied and figured out based on their features and behaviors. This study introduces a deep learning algorithm to identify different malware families. To implement the proposed approach, malware color-based images (RBG) are used directly. Then these malware images are identified and classified by considering the benefits of leveraged Convolutional Neural Networks (CNNs), which have the ability to automatically extract those features. A challenging malware classification experiment using the MaleVis dataset confirms that the adapted model outperforms better functional classification compared to the traditional machine learning models and achieves very good accuracy based on the MaleVis dataset.
Mohamed Elalem
IEEE
The performance of multichannel transmission in spectrum sharing system is studied in this paper. Both QoS constraints and interference limitations are considered. The activities of the primary users (PU)s are initially detected by secondary users (SU)s who perform sensing process over multiple channels. They transmit in a single channel at variable power and rates depending on the channel sensing decisions and the fading environment. The cognitive operation is modeled as a state transition model in which all possible scenarios are studied. The QoS constraint of the secondary users is investigated through statistical analysis. Analytical form for the effective capacity of the cognitive radio channel is found. Optimal power allocation and optimal channel selection criterion are obtained. Impact of several parameters on the transmission performance, as channel sensing parameters, number of available channels, fading and others, are identified through numerical example.
Mohamed Elalem and Lian Zhao
IEEE
In this paper, the performance of multichannel transmission in cognitive radio is studied. Both QoS constraints and interference limitations are considered. The activities of the primary user (PU) are initially detected by cognitive user (CU) who performs sensing process over multiple channels. The CU transmits over a single channel at variable power and rates depending on the channel sensing decision and the fading environment. The cognitive operation is modeled as a state transition model in which all possible scenarios are studied. The QoS constraint of the cognitive user is investigated through statistical analysis. Analytical form for the effective capacity of the cognitive radio channel is found. Optimal power allocation and optimal channel selection criterion are obtained. Impact of several parameters on the transmission performance, as channel sensing parameters, number of available channels, fading and others, is demonstrated through numerical example.
Mohamed Elalem and Lian Zhao
IEEE
Traditionally, the frequency spectrum is licensed to users who have the exclusive right to access the allocated band. However, an unlicensed (cognitive) user may share a frequency band with a licensed (primary) owner as long as the interference is below a certain threshold. This makes capacity analysis a critical important issue in these networks. Lots of research on cognitive radio (CR) networking have now focused on the satisfaction of quality-of-service (QoS) demands for cognitive users (CU). In this paper, we study how the delay QoS requirements affect the dynamic spectrum access (DSA) strategy on network performance. We treat the delay-QoS in interference constrained cognitive radio network by applying the effective capacity concept, focusing on one of the dominant DSA schemes: overlay. Optimal power allocation scheme is obtained. This scheme considers the transmit-power/interference-power constraints and the primary user activity. Performance analysis and numerical evaluations demonstrate the proposed effective capacity optimization on the DSA overlay scheme. The impact of delay QoS requirements and other related parameters are evaluated as well.
Mohamed Elalem and Lian Zhao
IEEE
Well-established fact shows that fixed spectrum allocation policy conveys to the low spectrum utilization. The cognitive radio technique promises to improve the low efficiency. This paper proposes an optimized access strategy combining overlay scheme and underlay scheme for the cognitive radio. We model the service state of the system as a continuous-time Markov model. Based on the service state, the overlay manner or the underlay manner is used by the secondary users. When the primary user is not transmitting and only one secondary user has the requirement to transmit, the secondary system adopts the overlay scheme. When the primary user is transmitting and the secondary users want to transmit simultaneously, an underlay scheme with an access probability is adopted. We obtain the optimal access probability which maximizes the overall system throughput.
M. Elalem and Lian Zhao
IEEE
As fundamental spectrum sensing and access techniques in cognitive radio networks (CRN) matured in last decade, the satisfaction of quality-of-service (QoS) demands for cognitive users (CU) has attracted lots of research attention. In this paper, we study how the delay QoS requirements affect the dynamic spectrum access (DSA) strategy on network performance. We first treat the delay-QoS in interference constrained cognitive radio network by applying the effective capacity theory, focusing on the dominant DSA scheme: underlay. We show that the roles that the transmit-power/interference-power constraints play in optimizing CUs' throughput vary significantly with the delay QoS requirements. Performance analysis and numerical evaluations are provided to demonstrate the effective capacity of CRN based on underlay scheme, taking into consideration the impact of delay QoS requirements and other related parameters.
Mohamed Elalem
IEEE
Traditionally, the frequency spectrum is licensed to users in a rigid manner where the licensee has the exclusive right to access the allocated band. However, an unlicensed (cognitive) user may share a frequency band with a licensed (primary) owner as long as the interference is below a certain threshold. This makes power control a critical important issue in these networks. In this paper, we consider a decentralized power control algorithm that satisfies the most two significant metrics in cognitive radio network, capacity of cognitive network and total interference to primary users. The problem might be formulated as a power optimization problem, where rate allocation and power control are modeled through the objective function in which each user utility depends not only on its variables but also on the variables of other user utilities. Geometric Programming (GP) Problem is used to convert nonconvex optimization problem to convex optimization problem by introducing auxiliary variables and adding extra equality constraints, thus transferring the coupling in the objective to coupling in the constraints, which can be decoupled by primal-dual decomposition method, then can be efficiently solved even with a large number of users. The benefits of the method are illustrated through numerical results.
Mohamed Elalem and Lian Zhao
IEEE
In order to utilize the spectrum efficiently, the FCC announced Cognitive Radio (CR) technology as a candidate to implement negotiated or opportunistic spectrum sharing. It has received a great attention due to the ability to improve the spectrum utilization. In such a CR network, power control can increase the efficiency by adjusting the transmission power of the secondary users (SU). In this paper, we propose an adaptive distributed power control scheme for CR networks where the conventional power control schemes used in cellular system are modified to be used in cognitive radio network to consider the QoS requirements of both the Primary User (PU) and the SU simultaneously. Since the transmission power of each SU is constrained so that the interference temperature at the primary receiver caused by all SUs does not exceed the interference tolerance of the PU. As a result, the QoS requirement for the PU is always guaranteed.
Mohamed Elalem, Lian Zhao, and Zaiyi Liao
IEEE
One of the challenging problems of cognitive radio networks is the interference which occurs when a cognitive radio accesses a licensed band but fails to notice the presence of the licensed user. To allow the cognitive radio to access the same spectrum band where the primary user is operating creates a problem, the cognitive radio may interfere with the primary system, and hence degrading the quality of service for the primary receiver. This paper presents an adaptive power control scheme for cognitive radio. The proposed scheme estimates the distance between the primary user and the cognitive radio, using the SNR as proxy for distance. On the basis of this information the cognitive radio adaptively changes its maximal transmit power to prevent the primary user from harmful interference. Numerical results are presented to demonstrate the effectiveness of the proposed algorithm.
Mohamed Elalem and Lian Zhao
IEEE
WCDMA is becoming widely accepted as one of the most promising solutions to meet the increasing demand for high-capacity wireless networks of the future. The most important inherent characteristic of WCDMA systems is their interference-limited capacity. The user distribution is a very important issue. In most previous studies it is assumed that the spatial distribution of the users is uniform within the cell. This paper presents a study of the effect of a selected user distribution on the performance of a WCDMA cellular system. A more realistic user distribution is chosen with specific parameters and a new interference distribution factor is developed as a function of these parameters. The capacity and coverage are compared for the uniform and nonuniform user distributions.