Mahamod Ismail

Universiti Kebangsaan Malaysia | ukm · Department of Electrical, Electronic and Systems Engineering

A heterogeneous vehicular network (HetVNET) is a promising network architecture that combines multiple network technologies such as IEEE 802.11p, dedicated short-range communication (DSRC), and third/fourth generation cellular networks (3G/4G). In this network area, vehicle users can use wireless fidelity access points (Wi-Fi APs) to offload 4G lon...

Non-orthogonal multiple access (NOMA) is a Fifth Generation (5G) technique that allows many users to simultaneously access the same time–frequency separating channels via successive interference cancellation (SIC) receiver. Cooperative NOMA (CNOMA) is an effective tool to prevent performance degradation of far users by allocating minimal power to u...

With the promising advances in the telecommunication and automotive industries, there are increasing concerns on the reliability of Intelligent Transportation Systems (ITS) applications and standardization efforts. Nowadays, vehicles are empowered with innovative communications and sensing capabilities to accelerate next-generation Connected and Au...

Relaying is a promising technique introduced in LTE-advanced network for coverage extensions, throughput and data rate enhancement. However, the current relay deployment tends to be non-optimal in term of the number of relays and their position between evolved Node B (eNB) and User Equipment (UE). In this study, we propose optimal relay deployment...

Cooperative Relay is a promising enhancement to modern radio technologies which has been considered in LTE-Advanced and IEEE 802.16m technologies. Cooperative Relay is one of the technologies that used to improve coverage in downlink mobile network. The work is done by designing numerous environments for LTE-Advanced networks involving relays, wher...

5G mobile communications is a paradigm shift in communication and internet technology. It aims to enable the networked society so that users, device, and machine can connect to high speed internet at anytime from anywhere. Nevertheless, the full description of the 5G is still emerging and issues related to the challenges that might face or confront...

Relaying is a promising technique introduced in LTE-advanced network for coverage extensions, throughput and data rate enhancement. However, the current relay deployment tends to be non-optimal in term of the number of relays and their position between evolved Node B (eNB) and User Equipment (UE). In this study, we propose optimal relay deployment...

Multi-path fading is a severe issue that causes fluctuations in the amplitudes of the received signals. For combating this issue, several researchers have used cooperative communication in the Long-Term Evolution (LTE)-advanced system. To further decrease the degradative effects of transmitted signals, various error correction techniques can be use...

Non-orthogonal multiple access (NOMA) is a Fifth Generation (5G) technique that allows many users to simultaneously access the same time–frequency separating channels via successive interference cancellation (SIC) receiver. Cooperative NOMA (CNOMA) is an effective tool to prevent performance degradation of far users by allocating minimal power to u...

This paper addresses a path loss prediction and optimization by means of Lee's model for Jiza town, south of Amman city, Jordan. Data were collected from mobile companies in Jordan in the frequency band of 900, and 1800 MHz. The calibrated Lee's, Hata, and Egli's path loss models were compared with respect to the original collected data. It is foun...

Wireless body area networks (WBANs) are an upcoming technology for achieving effective healthcare. The security and privacy of patient-related data are two essential aspects of WBAN system security. Storing data on a single server is simple but may lead to a single point of failure (whether a typical failure or a failure due to security attacks). I...

Inter-Cell Interference (ICI) could affect the performance of the LTE-Advanced (LTE-A) system and can be evaluated according to the user’s Signal to Interference and Noise Ratio (SINR). Owing to this, the power and frequency allocation schemes can be utilized in order to attain an optimum trade-off within the obtained SINR and the resulting interfe...

Vehicular Ad Hoc Networks (VANETs) have emerged as an exciting research and application area. Increasingly vehicles are being equipped with embedded sensors, processing and wireless communication capabilities. This has opened major possibilities for powerful and potential life-changing applications on safety, efficiency, comfort, public collaborati...

This paper proposes a new precoding approach that utilizes two-dimension (2D) Angle of Arrival (AOA) based precoding (beamforming) approach for multi-cell massive Multiple Input Multiple Output (m-MIMO) systems. The proposed approach enhances the performance of m-MIMO systems by overcoming pilot contamination that is caused by corrupted Channel Sta...

Vehicular Ad Hoc Networks (VANETs) is an important field of study nowadays. VANETs attracts attention of vehicles communication researcher due to its potential to improve vehicle road safety, enhance traffic and travel efficiency, and provide convenience and comfort for passengers and drivers. Due to the fact that modern life, especially when trave...

This work presents a three-dimensional ray tracing algorithm for propagation prediction in indoor wireless networks. The algorithm uses a mathematical model to represent the building constructions with different types of materials. The model also represents the propagation of electromagnetic signals by using the geometry theory of diffraction. The...

Modern wireless communication like 5G systems are expected to serve a wider range of scenarios than current mobile communications systems. One of the major network applications related to 5G is Vehicle-to-Vehicle (V2V) communication that improves vehicle road safety, enhances traffic and travel efficiency, and provides convenience and comfort for p...

Vehicular communication networks is a powerful tool that enables numerous vehicular data services and applications. The rapid growth in vehicles has also resulted in the vehicular network becoming heterogeneous, dynamic, and large-scale, making it hard to meet the strict requirements, such as extremely latency, high mobility, top security, and enor...

Flood is the most frequent disaster in the world. The impact of floods is very large, like human and animal death, the villages vanished and other environments damaged. In disaster preparedness, it is very necessary to divide the stages of the disaster status level. Therefore the public can prepare themselves according to these stages. The stage of...

Femtocells have become an integral part of mobile heterogeneous network which is now being widely utilized as solution of coverage and bandwidth limitation. Coverage area could be expanded, and enormous volumes of traffic can be relieved from macro cell. Coexistence of numerous femtocells in macrocells coverage area certainly need a robust mechanis...

The demand for higher data traffic is exponentially growing. Since last 2 years or so, new research movements have emerged towards LTE-B (Release 13 and beyond) and 5th generation (5G) networks. As the next generation of cellular networks are going to be an integration of different radio access technologies and denser in term of space and frequency...

span>It is worth mentioning that the use of wireless systems has been increased in recent years and supposed to highly increase in the few coming years because of the increasing demands of wireless applications such as mobile phones, Internet of Things (IoT), wireless sensors networks (WSNs), mobile applications and tablets. The scarcity of spectru...

Abstract—In order to overcome the spectrum scarcity in 5G networks, spectrum sharing is being studied relying on Cognitive Radio (CR) technology. Even with the new spectrum resources (millimeter-wave) for future networks, sharing the spectrum below 6 GHz and above will be necessary. The four stages as processes to achieve spectrum sharing were clas...

Ensuring a reliable and stable communication throughout the mobility of User Equipment (UE) is one of the key challenges facing the practical implementation of the Fifth Generation (5G) networks and beyond. One of the main issues is the use of suboptimal Handover Control Parameters (HCPs) settings, which are configured manually or generated automat...

To handle the huge traffic in cellular networks and increase the offered bandwidth for User Equipment (UE), we proposed two enhanced methods to simultaneously access the channels in Heterogeneous Bands (HetBands). The Enhanced Dual Band Femtocell (EDBF) is utilized in single Radio Access Technology (RAT) that comprises Long Term Evolution (LTE) onl...

Received signal strength (RSS)-based was proposed in this paper by adopting attribute handover decision algorithm to investigate network selection decision model based on lifetime connectivity that makes the mobile user equipment (MUEs) stay longer in a preferred network. Quality of service (QoS) as an important parameter is achieved by introducing...

Wireless sensor networks (WSNs) have received significant attention in the last few years in the agriculture field. Among the major challenges for sensor nodes’ deployment in agriculture is the path loss in the presence of dense grass or the height of trees. This results in degradation of communication link quality due to absorption, scattering, an...

In this paper, an Adaptive Handover Margin algorithm based on Novel Weight Function (AHOM-NWF) is proposed through Carrier Aggregation operation in Long Term Evolution—Advanced system. The AHOM-NWF algorithm automatically adjusts the Handover Margin level based on three functions, f(SINR),f(TL)andf(v), which are evaluated as functions of Signal-to-...

The upcoming fifth-generation wireless mobile systems are projected to be commercialized in the year 2020 and are set to play the main role in massive multiple input-multiple output (mMIMO) integrated with the technologies of beamforming antenna arrays. However, the performance of mMIMO is constrained by inter-cell interference from adjacent cells...

In this paper a low profile patch antenna has been designed for 5G communication application. The resonating frequency has been chosen as 3.5 GHz for 5G application. FR4 epoxy material with permittivity of 4.3 has been chosen for the substrate material which has fire redundant property. The size of the substrate is 25.2×48 mm ² . The main radiating...

Wireless sensor network is consisting of power-limited sensors that sense the surrounding environment and transmit data to another sensor or to the particular gateway. Thus, a considerable amount of energy is dissipated which impact the overall performance and network lifetime. In order to mitigate the failure-based energy, routing and clustering m...

The large network architecture of today consists of thousands of computers connected together through many interconnecting router and switches. As many of them communicate concurrently, congestion over the channels may increase. In order to maintain the fairness among the transmission control protocol (TCP) based packets being sent, during congesti...

Beamforming (BF) technique in cooperative multiple input multiple output (MIMO) antenna arrays improves signal to noise ratio (SNR) of the intended user. The challenge is to design transmit beamforming vectors for every user while limiting the co-channel interference (CCI) from other users. In this paper, we proposed cooperative beamforming based o...

One of the most notable challenges in wireless communications is energy scarcity, which has attracted considerable attention in Fifth Generation (5G) wireless network research. This paper investigates the performance of energy harvesting (EH) relays under the best relay selection (BRS) scheme. The results show degradation of spectral efficiency (SE...

Convergence of typical wireless networks (MANET and WSN) is paving the way towards brand-new cooperative platforms for Internet of Things (IoT) communications. The IoT enables the global connectivity of a wide variety of heterogeneous objects in accordance with their battery capacity, processing capabilities, and mobility to serve people in a colla...

The massive multiple-input-multiple-output technology relies on many antennas at base stations to offer high throughput to meet fifth-generation (5G) network requirements. However, each base station requires accurate channel state information (CSI) during channel estimation. Pilot contamination is one of the significant challenges that limit higher...

The large network architecture of today consists of thousands of computers connected together through many interconnecting router and switches. As many of them communicate concurrently, congestion over the channels may increase. In order to maintain the fairness among the transmission control protocol (TCP) based packets being sent, during congesti...

The use of wireless sensor networks (WSNs) in modern precision agriculture to monitor climate conditions and to provide agriculturalists with a considerable amount of useful information is currently being widely considered. However, WSNs exhibit several limitations when deployed in real-world applications. One of the challenges faced by WSNs is pro...

Millimeter wave bands have been introduced as one of the most promising solutions to alleviate the spectrum secrecy in the upcoming future cellular technology (5G) due the enormous amount of raw bandwidth available in these bands. However, the inherent propagation characteristics of mmWave frequencies could impose new challenges i.e. higher path lo...

p>Millimeter wave bands have been introduced as one of the most promising solutions to alleviate the spectrum secrecy in the upcoming future cellular technology (5G) due the enormous amount of raw bandwidth available in these bands. However, the inherent propagation characteristics of mmWave frequencies could impose new challenges i.e. higher path...

Cooperative Non-orthogonal multiple access (NOMA) is an effective solution to prevent the degradation in performance of the far users, by allocating less power to users with better channel conditions. The challenge for the base station is to decide how to allocate the power among the individual information waveforms, so we proposed cooperative NOMA...

This paper investigates the performance of Energy Harvesting (EH) relaying with link adaptation for two combining schemes based on amplify-and-forward relaying systems. The first scheme defined as All Relay Participate (ARP), where the destination combines the received signals from all the relays, while the second scheme is known as Best Relay Sele...

The aim of this paper is to present a simulation and analysis of a rectangular microstrip patch antenna with three different structural modifications to reduce the size of the antenna. We have tried to decrease the size of the antenna by inducing three different shaped slits inside the patch of the antenna. All these models have been designed and a...

Energy harvesting is an alternative approach to extend the lifetime of wireless communications and decrease energy consumption, which results in fewer carbon emissions from wireless networks. In this study, adaptive modulation with EH relay is proposed. A power splitting mechanism for EH relay is used. The relay harvests energy from the source and...

Single-tube loop coil (STLC) and multi-turn copper wire coil (MTCWC) wireless power transfer (WPT) methods are proposed in this study to overcome the challenges of battery life during low-power home appliance operations. Transfer power, efficiency, and distance are investigated for charging mobile devices on the basis of the two proposed systems. T...

When localizing wireless sensor networks (WSNs), estimating the distances of sensor nodes according to the known locations of the anchor nodes remains a challenge. As nodes may transfer from one place to another, a localization technique that can measure or determine the location of a mobile node is necessary. In this paper, the distance between a...

In wireless localisation, time-based Location Determination Technology (LDT) with minimum error is one of the crucial techniques that can be used to improve resource management and quality of services. This study aims to improve the location accuracy of mobile user by using a hybrid time-based LDT. In this paper, minimising of the mobile estimation...

The increasing use of smartphones, tablets, and other vehicular network applications with varied capabilities and the associated growth in the use of all types of data-hungry multimedia services pose a significant challenge to cellular infrastructure operators. Vehicular Wi-Fi offloading (VWO) is one of the potential solutions for offloading cellul...

There are many platforms in licensed and license free spectrum that support LPWA (low power wide area) technology in the current markets. However, lack of standardization of the different platforms can be a challenge for an interoperable IoT environment. Therefore understanding the features of each technology platform is essential to be able to dif...

High vehicular mobility causes frequent changes in the density of vehicles, discontinuity in inter-vehicle communication, and constraints for routing protocols in vehicular ad hoc networks (VANETs). The routing must avoid forwarding packets through segments with low network density and high scale of network disconnections that may result in packet...

The increasing demand for wireless networks calls for the use of heterogeneous networks in order to fulfil user requirements. Mobility management is considered one of the important entities for such networks. The handover is one of the main features of mobility management in regard to the long term evolution advanced (LTE-A) system, which depends p...

High vehicular mobility causes frequent changes in the density of vehicles, discontinuity in inter-vehicle communication, and constraints for routing protocols in vehicular ad hoc networks (VANETs). The routing must avoid forwarding packets through segments with low network density and high scale of network disconnections that may result in packet...

Spectrum and infrastructure sharing among multiple mobile network operators is a vital solution to substantially and sustainably improves cost and network efficiency. However, such approach may face several challenges, such as the imposed restrictions on the independence of operators, the complexity of spectrum management policies and the mutual in...

One of the challenges in massive-MIMO system is pilot contamination during the channel estimation process. Pilot contamination can cause error or inaccurate channel estimation process for future fifth generation (5G) downlink transmissions. This paper considers using a Wiener-based filter to smooth and predict the channel estimation to reduce the p...

The handover is one of the basic elements in the mobility management of Long Term Evolution Advanced (LTE-A) wireless systems. It permits the user equipment (UE) to wander between LTE-A wireless networks. LTE-A purely depends on the hard handover, which may cause disconnection to occur if the handover is not fast enough. In this paper, an advanced...

Network densification is one of the imperative mechanisms expected to enable next generation 5G networks to meet the highly foreseen 1000-fold increase in capacity. In this regard, densification of femtocells is a promising concept to meet growing mobile service requirements and for sustainability of users’ Quality of Service (QoS), especially for...

This book addresses space science and communication – one of the main pillars of space science sustainability, an area that has recently become of great importance. In this regard, research and development play a crucial role in sustainability development. However, obtaining essential data in the physical world to interpret the universe and to pred...

The high demand of using wireless communication leads to establish a new technique of modulation to enhance the throughput of the system and to have a high data rate communication. One of the modern wireless modulation techniques is the Orthogonal Frequency Division multiplexing (OFDM) which considered a suitable technique of modulation in modern w...

Relay stations play an important role in throughput increase data rate and extending coverage for LTE-advanced. One solution to throughput increase data rate and extend the coverage is to use the fixed relays to transmit data between the eNB and UE through multi hop communication. In this study, we propose new study focusing on the optimal deployme...

The IEEE 802.22 Standard targets rural and sparsely populated regions exploiting Television white space (TVWS) technology. In these regions, there are fewer mobile users per density and end-users traffic is light. Hence, there is a need to adopt traffic aware algorithm leveraging on the end-users nonuniform traffic attributes and in essence, promot...

In MANETs, data routing is a critical issue due to frequent network’s topological changes and the unbalanced load distribution among nodes. The hybrid MultiPath Optimized Link State Routing protocol version two (MP-OLSRv2), which is the most recent and popular protocol proposed in this area, and is represented an effective solution to such issues b...

Spectrum trading is an important aspect of Television White Space (TVWS) and it is driven by the failure of spectrum sensing techniques. In spectrum trading, the Primary Users (PUs) lease their unoccupied spectrum to the Secondary Users (SUs) for a market fee. Although spectrum trading is considered as a reliable approach, it is confronted with a s...

In wireless Ad hoc networks, congestion occurs frequently at intermediate nodes when forwarding data packets between source-destination pairs. This traffic incurs higher packet loss, longer transmission delay, and faster energy resources depletion, thus degrades the performance of the network. This paper analyzes the performance of our hybrid Multi...

The increasing demand for mobile communication calls for improvements to network operating services in terms of capacity, coverage, and Quality of Services (QoS). Ensuring QoS is one of the challenges faced by wireless network operators, which include the provision of high mobility speeds, thus the implementation of a seamless and fast handover bet...

System information (SI) acquisition is a mandatory component for inbound handover (HO) to closed subscriber group femtocells in LTE/LTE-Advanced networks. In this paper, we analyze theoretically and numerically several existing SI acquisition schemes such as scheduled, semi scheduled and autonomous SI acquisition scheme. We found that using those s...

Rainfall is a major destructive factor which severely reduces the quality and reliability of propagated signals in satellite communications. Hence, rain-attenuation prediction plays a vital role in the satellite radio link planning and engineering. The accuracy of the rain-attenuation prediction models depends on two things; (i) the accuracy of rai...

Wireless sensor networks (WSNs) can be used in agriculture to provide farmers with a large amount of information. Precision agriculture (PA) is a management strategy that employs information technology to improve quality and production. Utilizing wireless sensor technologies and management tools can lead to a highly effective, green agriculture. Ba...

Ubiquitous smart devices with embedded sensors are paving the way for mobile ad hoc networks (MANETs) that enable users to communicate directly, thereby playing a key role in Smart City and Internet of Things applications. In such smart environments, people with smart devices (nodes) can freely self-organize and form self-configuring MANETs to send...