Ahmed Yassin Al-Dubai

Recent Advances in Indoor Localization: A Survey on Theoretical Approaches and Applications

The availability of location information has become a key factor in today’s communications systems allowing location based services. In outdoor scenarios, the mobile terminal position is obtained with high accuracy thanks to the global positioning system (GPS) or to the standalone cellular systems. However, the main problem of GPS and cellular systems resides in the indoor environment and in scenarios with deep shadowing effects where the satellite or cellular signals are broken. In this paper, we survey different technologies and methodologies for indoor and outdoor localization with an emphasis on indoor methodologies and concepts. Additionally, we discuss in this review different localization-based applications, where the location information is critical to estimate. Finally, a comprehensive discussion of the challenges in terms of accuracy, cost, complexity, security, scalability, etc. is given. The aim of this survey is to provide a comprehensive overview of existing efforts as well as auspicious and anticipated dimensions for future work in indoor localization techniques and applications.

A new dynamic counter-based broadcasting scheme for Mobile Ad hoc Networks

Broadcasting is an essential operation in Mobile Ad hoc Networks (MANETs) to transmit a message (data packet) from the sender to the rest of the network nodes. Although flooding is the simplest mechanism for broadcasting, where each node retransmits every uniquely received message exactly once, it is usually costly and results in serious redundancy, contention and collisions in the network. These problems are widely referred to as the broadcast storm problem. In the light of this, this study introduces a new counter-based broadcasting scheme to achieve efficient broadcasting in MANETs. This is achieved by using a counter-based scheme with a dynamic threshold to increase the successful delivery rate of packets and enhance the throughput of the network. Extensive simulation experiments have been conducted. Our results show that the new scheme outperforms the well known exiting schemes, namely the two counter-based broadcasting scheme and blind flooding.

A new probabilistic broadcasting scheme for mobile ad hoc on-demand distance vector (AODV) routed networks

Broadcast is a fundamental operation used in Mobile Ad hoc NETworks (MANETs) for many services, such as route discovery and sending information messages. The direct method to perform broadcast is a simple flooding, which can decrease the performance of MANET. Recently, a probabilistic approach to flooding has been proposed as one of most important suggested solutions to solve the broadcast storm problem, which leads to the collision, contention and duplicated messages. This paper presents the Smart Probabilistic Broadcasting (SPB) as a new probabilistic method to improve the performance of existing on-demand routing protocols by reducing the RREQ overhead during the rout discovery operation. The simulation results show that the combination of AODV and a suitable probabilistic rout discovery can reduce the average end-to-end delay as well as overhead, while achieving low normalized routing load, compared to AODV that uses fixed probability and blind flooding. Simulation experiments have been conducted to examine our proposed scheme. The results show that SPB outperforms its counterparts and opens up a promising framework towards optimal probabilistic broadcasting.

GLBM: A new QoS aware multicast scheme for wireless mesh networks

Wireless mesh networks (WMNs) have been attracting significant attention due to their promising technology. The WMN technology is becoming a major avenue for the fourth generation of wireless mobility. Communication in large-scale wireless networks can create bottlenecks for scalable implementations of computationally intensive applications. A class of crucially important communication patterns that have already received considerable attention in this regard are group communication operations, since these inevitably place a high demand on network bandwidth and have a consequent impact on algorithm execution times. Multicast communication has been among the most primitive group capabilities of any message passing in networks. It is central to many important distributed applications in science and engineering and fundamental to the implementation of higher-level communication operations such as gossip, gather, and barrier synchronisation. Existing solutions offered for providing multicast communications in WMN have severe restriction in terms of almost all performance characteristics. Consequently, there is a need for the design and analysis of new efficient multicast communication schemes for this promising network technology. Hence, the aim of this study is to tackle the challenges posed by the continuously growing need for delivering efficient multicast communication over WMN. In particular, this study presents a new load balancing aware multicast algorithm with the aim of enhancing the QoS in the multicast communication over WMNs. Our simulations experiments show that our proposed multicast algorithm exhibits superior performance in terms of delay, jitter and throughput, compared to the most well known multicast algorithms.

Performance Modelling and Analysis of Cognitive Mesh Networks

A new analytical model is proposed to investigate the delay and throughput in cognitive mesh networks. The validity of the model is demonstrated via extensive simulation experiments. The model is then used to evaluate the effects of the number of licensed channels and channel utilisation on the network performance.

An efficient neighbourhood load routing metric for wireless mesh networks.

Abstract The Wireless Mesh Network (WMN) is a highly capable technology that can offer low-cost and easy-deployable network connectivity to both small-size community networks and large-scale metropolitan networks. As a key emerging technology to provide the next generation broadband networking, WMN combines the advantages of both mobile ad hoc network (MANET) and traditional fixed network, attracting significant industrial and academic attentions. In WMN, the load balancing has already shown its key role in enhancing communication quality by providing reduced latency, jitter and error rate as well as improving bandwidth utilisation and allocation polices. Although there are a number of proposals on using load-aware strategy in WMN, the neighbourhood load has not been considered within the context of load balancing and high efficient WMNs. In this paper, we propose a Neighbourhood Load Routing metric to further improve the performance of existing routing protocols such as AODV in WMN. We have conducted extensive simulation experiments and our results confirm the superiority of our proposed scheme over its well-known counterparts, especially in grid topologies.

A QoS aware multicast algorithm for wireless mesh networks

Wireless mesh networks have been attracting significant attention due to its promising technology. It is becoming a major avenue for the fourth generation of wireless mobility. Communication in large-scale wireless networks can create bottlenecks for scalable implementations of computationally intensive applications. A class of crucially important communication patterns that have already received considerable attention in this regard are group communication operations, since these inevitably place a high demand on network bandwidth and have a consequent impact on algorithm execution times. Multicast communication has been among the most primitive group capabilities of any message passing networks. It is central to many important distributed applications in Science and Engineering and fundamental to the implementation of higher-level communication operations such as gossip, gather, and barrier synchronisation. Existing solutions offered for providing multicast communications in WMN have severe restriction in terms of almost all performance characteristics. Consequently, there is a need for the design and analysis of new efficient multicast communication schemes for this promising network technology. Hence, the aim of this study is to tackle the challenges posed by the continuously growing need for delivering efficient multicast communication over WMN. In particular, this study presents a new load balancing aware multicast algorithm with the aim of enhancing the QoS in the multicast communication over WMNs.

New adaptive counter based broadcast using neighborhood information in MANETS

Broadcasting in MANETs is a fundamental data dissemination mechanism, with important applications, e.g., route query process in many routing protocols, address resolution and diffusing information to the whole network. Broadcasting in MANETs has traditionally been based on flooding, which overwhelm the network with large number of rebroadcast packets. Fixed counter-based flooding has been one of the earliest suggested approaches to overcome blindflooding or the “broadcast storm problem”. As the topological characteristics of mobile networks varies instantly, the need of an adapted counter-based broadcast emerge. This research argues that neighbouring information could be used to better estimate the counter-based threshold value at a given node. Additionally results of extensive simulation experiments performed in order to determine the minimum and maximum number of neighbours for a given node is shown. This is done based on locally available information and without requiring any assistance of distance measurements or exact location determination devices.

Wireless Body Area Network (WBAN): A Survey on Reliability, Fault Tolerance, and Technologies Coexistence

Wireless Body Area Network (WBAN) has been a key element in e-health to monitor bodies. This technology enables new applications under the umbrella of different domains, including the medical field, the entertainment and ambient intelligence areas. This survey paper places substantial emphasis on the concept and key features of the WBAN technology. First, the WBAN concept is introduced and a review of key applications facilitated by this networking technology is provided. The study then explores a wide variety of communication standards and methods deployed in this technology. Due to the sensitivity and criticality of the data carried and handled by WBAN, fault tolerance is a critical issue and widely discussed in this paper. Hence, this survey investigates thoroughly the reliability and fault tolerance paradigms suggested for WBANs. Open research and challenging issues pertaining to fault tolerance, coexistence and interference management and power consumption are also discussed along with some suggested trends in these aspects.

Performance Evaluation of RPL Objective Functions

Recently, IETF standardised a powerful and flexible Routing Protocol for Low Power and Lossy Networks (RPL). It selects the ideal routes from a source to a destination node based on certain metrics injected into the Objective Function (OF). In this study, the performance of RPL has been investigated in terms of two OFs (i.e. Minimum Rank with Hysteresis Objective Function (MRHOF) and Objective Function Zero (OF0)) in various topologies (grid, random) which makes this work distinctive. To study the RPL OFs performance, various parameters are considered Packet Delivery Ratio (PDR), Power Consumption and RX. The evaluation has been conducted based on these parameters (RX, topology) and compared for both OFs. The simulation results revealed that these parameters have a great impact on the PDR and achieved saved energy levels in the given networks. Our results have also indicated that the performance of RPL within light density networks for MRHOF can provide a better RPL behavior that OF0 could not provide.