Papers by Mohammad Abdellatif
Arabian journal for science and engineering, Jan 31, 2013
In this paper, we derive the error probability of multi-hop networks employing code-division mult... more In this paper, we derive the error probability of multi-hop networks employing code-division multiple access transmission in a multiuser environment. The standard Gaussian approximation is used to model the multiple access interference in the network. We consider multi-hop networks employing serial, parallel, and selection relaying using the decode-and-forward technique. For the selection relaying, we consider two schemes; namely, the threshold-based relay selection and the maximum relay selection. In addition, we investigate the effect of different system parameters on the error performance of the system, such as the spreading gain, the number of interfering users, and the path loss exponent. Results show that as the number of users increases, the improvement coming from the relaying decreases.
2022 5th Conference on Cloud and Internet of Things (CIoT)
2022 IEEE Global Conference on Artificial Intelligence and Internet of Things (GCAIoT)
Ain Shams Engineering Journal
2021 10th International Conference on Software and Information Engineering (ICSIE), 2021
As the number of wireless devices is increasing daily, the radio frequency spectrum is becoming m... more As the number of wireless devices is increasing daily, the radio frequency spectrum is becoming more crowded. Moreover, due to the stochastic nature of wireless communications technologies, some frequency bands which are allocated to services or users can be underutilized. On the other hand, some users may not be able to access the medium as all the frequency bands have been already allocated to different users. Cognitive radio has gained a lot of interest in the past few years as it tackles the problem of spectrum scarcity by taking advantage of spectrum holes that are available in the frequency spectrum. Spectrum Sensing is the tool that cognitive radio nodes use to find such holes. A cognitive radio node senses the frequency band, and if it is found to be free, uses it to transmit and receive data. There are two main sensing schemes, Energy Detection, and cooperative sensing. In this paper, we give an overview of these two main schemes focusing on their limitations and ways to optimize their performance in cognitive radio networks.
Journal of Communications
Vehicular Ad-hoc Networks VANETs are normally sparse, highly dense, and highly mobile with many d... more Vehicular Ad-hoc Networks VANETs are normally sparse, highly dense, and highly mobile with many different and ever-changing topologies. These characteristics impose a challenge on finding a routing algorithm that fits the requirements of such network. The aim of this work is to study the performance issues of VANETs under different scenarios using realistic mobility models. In this paper, a comparative study is done among Ad-hoc On- Demand Distance Vector (AODV), Optimized Link State Routing (OLSR) and position-based routing protocols, namely Greedy Perimeter stateless routing (GPSR), and Max duration Min angle GPSR (MMGPSR). The comparison is done using key quality of service QoS metrics such as average routing goodput, end-to-end delay, MacPhy overhead, and packet delivery ratio PDR. The study is conducted using Network Simulator 3 (NS3) and SUMO.
IEEE Access
In this article, the spectrum trading problem between primary users and secondary networks is inv... more In this article, the spectrum trading problem between primary users and secondary networks is investigated. The secondary network requests multiple channels with the targeted availability to satisfy its users' demands. Due to the uncertainty about the channels availability, stochastic optimization techniques are adopted to find the optimal set of channels for each secondary network for the lowest cost. Two different constraints on the secondary demand are defined. The first one is when the throughput has to be fully satisfied for a certain percentage of time, and the second one is when the expected value of the throughput has to exceed a certain percentage of the requested one. Also, the possibility for channel subleasing among the secondary networks is investigated to reduce the demand shortage. The results show that demanding simultaneous channels increases the cost as it reaches up to 20% higher than if the same resources were requested individually. Also, channels subleasing reduces the demand shortage probability and increases the achieved throughput, especially at low value of requested demand. In this case, the demand satisfaction probability increases by around 30% while the achieved throughput increases up to 40% compared to the scenario where channels subleasing is not allowed.
2021 10th International Conference on Software and Information Engineering (ICSIE), 2021
Telecommunication Systems, 2015
Wireless sensor networks (WSNs) may be made of a large amount of small devices that are able to s... more Wireless sensor networks (WSNs) may be made of a large amount of small devices that are able to sense changes in the environment, and communicate these changes throughout the network. An example of a similar network is a photo voltaic (PV) power plant, where there is a sensor connected to each solar panel. The task of each sensor is to sense the output of the panel which is then sent to a central node for processing. As the network grows, it becomes impractical and even impossible to configure all these nodes manually. And so, the use of self-organization and auto-configuration algorithms becomes essential. In this paper, three algorithms are proposed that allow nodes in the network to automatically identify their closest neighbors, relative location in the network, and select which frequency channel to operate in. This is done using the value of the Received Signal Strength Indicator (RSSI) of the messages sent and received during the setup phase. The performance of these algorithms is tested by means of both simulations and testbed experiments. Results show that the error in the performance of the algorithms decreases as we increase the number of RSSI values used for decision making. Additionally, the number of nodes in the network affects the setup error. However, the
2008 2nd International Conference on Signal Processing and Communication Systems, 2008
Multi-hop networks help in combating fading by employing a distributed space diversity system. Th... more Multi-hop networks help in combating fading by employing a distributed space diversity system. The performance of the system can be further enhanced by employing a good error control code such as convolutional codes, which provide low implementation complexity and short delays. In this paper we investigate the error performance of a convolutionally coded multihop ad-hoc network in an OFDM wireless environment with serial and selection relaying. In particular, we investigate the effect of relaying scheme, channel, bandwidth, and path loss exponent on the performance. Results show that the relaying improves the system greatly especially in the case of selection relaying and in high pat loss environments.
2013 IFIP Wireless Days (WD), 2013
Proceedings of the International Symposium on Wireless Communication Systems, 2012
Wireless Sensor Networks (WSNs) consist of small devices with processing, communication and sensi... more Wireless Sensor Networks (WSNs) consist of small devices with processing, communication and sensing capabilities. These devices interact together to carryout monitoring tasks. An example of such network is a photo-voltaic (PV) power plant where each solar panel has a sensor. The number of interconnected solar panels can become very large, and spread over a large area. Each sensor will sense the output of the panel and send this value to a central node for processing. In this paper we evaluate the performance of a wireless sensor network employing three different data collecting techniques. The study considers different networks, each with a different number of nodes and with different values for the offered load, estimating for each network size and offered load, network throughput, packet loss and end-to-end packet delay. Results show that as the size of the network grows and for higher values of the offered load, the best performance is achieved by using a polling based data collecting technique.
Arabian Journal for Science and Engineering, 2013
In this paper, we derive the error probability of multi-hop networks employing code-division mult... more In this paper, we derive the error probability of multi-hop networks employing code-division multiple access transmission in a multiuser environment. The standard Gaussian approximation is used to model the multiple access interference in the network. We consider multi-hop networks employing serial, parallel, and selection relaying using the decode-and-forward technique. For the selection relaying, we consider two schemes; namely, the threshold-based relay selection and the maximum relay selection. In addition, we investigate the effect of different system parameters on the error performance of the system, such as the spreading gain, the number of interfering users, and the path loss exponent. Results show that as the number of users increases, the improvement coming from the relaying decreases.
2014 13th Annual Mediterranean Ad Hoc Networking Workshop (MED-HOC-NET), 2014
Wireless Sensor Networks (WSNs) are made of a large amount of small devices that are able to sens... more Wireless Sensor Networks (WSNs) are made of a large amount of small devices that are able to sense changes in the environment, and communicate these changes throughout the network. An example of such network is a photo voltaic (PV) power plant, where there is a sensor connected to each solar panel. Because such a network covers a large area, the number of sensors can be very large. The task of each sensor is to sense the output of the panel which is then sent to a central node for processing. As the network grows, it becomes impractical and even impossible to configure all these nodes manually. And so, the use of self-organization and auto-configuration algorithms becomes essential. In this paper, two algorithms are proposed that can be used to allow each node in the network to automatically identify its closest neighbors as well as its relative location in the network using the value of the Received Signal Strength indicator (RSSI) of the messages sent back and forth during the setup phase. Results show that the error in neighbor identification decreases as we increase the number of RSSI values used for decision making. Additionally, the number of nodes in the network affects the setup error greatly. However, the value of the error is still acceptable even for high number of simulated columns.
Industrial controller systems are crucially essential to the cutting edge power systems industrie... more Industrial controller systems are crucially essential to the cutting edge power systems industries. Electric services are expected to determine the best media tool to be used for any distribution. The communication systems contribute towards a physical intermediary layer for transferring, controlling and acquirement of data within the system from distant locations. This paper discusses the Supervisory Control and Data Acquisition (SCADA) systems and proposes a similar system that is an IoT based industrial wireless controller. The proposed system can control multiple devices through the internet without the need to be physically near the devices. Because it uses simple and cheap devices, the system is low cost and easy to install. Additionally, the system is modular because extra microcontrollers can be added to the system to control more devices should the need arise.
2018 IEEE Global Conference on Internet of Things (GCIoT), 2018
Cellular networks may suffer from outage due to overload from user demands or from man made or na... more Cellular networks may suffer from outage due to overload from user demands or from man made or natural disasters. and so, researchers have been considering alternative scenarios for maintaining connectivity during such outage. Mobile ad hoc networks (MANETs) and Device-to-Device (D2D) communication are two of the main technologies considered. Such ideas are usually implemented in places with no infrastructure such as in oceans, forests, and deserts. However, they can also be used during network outage. This paper proposes a low cost wireless communications solution that enables users to make voice calls in uncovered areas or in the case of a disaster. A mobile App was designed to enables voice calls and to test the performance of the call using cellular networks, VOIP, or D2D communications. Moreover, the transmission delay of the D2D solution is experimentally calculated and a recommendation of the most suitable technology is highlighted based on the obtained results.
2019 International Conference on Advances in the Emerging Computing Technologies (AECT), 2020
Nowadays, technology has become more reliable that allowed human interaction to decrease while th... more Nowadays, technology has become more reliable that allowed human interaction to decrease while the machines have started to take over in many fields of interest. The Internet of things (IoT) represents the idea of machines ability to control entire systems without any human interactions. This paper proposes an IoT system that takes a picture of parked cars in a garage, extract the plate number and the location of the car, and places these information in a database. At the garage entrance, a terminal linked to the system allows the user to locate the parked car using the license plate no.. The system is tested for reading license plates several times, and is shown to perform with a low probability of error. The proposed IoT parking system is an integrated system combining the RPi operating system Motion Eye, with MATLAB segmentation code for character recognition, database tools, as well as web services all in order to make the user interface as friendly as possible.
2017 IEEE 13th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob), 2017
Dynamic Spectrum Access (DSA) has been proposed to increase the spectrum utilization efficiency a... more Dynamic Spectrum Access (DSA) has been proposed to increase the spectrum utilization efficiency and to solve the spectrum scarcity problem. However, due to the spectrum sharing and opportunistic access nature of the DSA networks, they are more vulnerable to security threats like jammers. In this paper, we propose an anti-jamming technique in which the secondary network coordinator groups the secondary users in smart collations over the different channels. By utilizing cooperative communication, the secondary users in these collations can boost their transmission against the effect of the jammer. The interaction between the secondary network and the jammer is modeled as a modified Colonel Blotto game in which the secondary network coordinators acts as the defender and the jammer as the attacker. A fictitious play based algorithm is used to find the mixed Nash strategy equilibrium solution of the game. The results show that utilizing cooperative communication enhances the performance ...
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Papers by Mohammad Abdellatif