Md. Arafatur Rahman

A simulation based performance comparison of routing protocol on Mobile Ad-hoc Network (proactive, reactive and hybrid)

Mobile Ad-hoc Network (MANET) is a collection of wireless mobile nodes which dynamically forms a temporary network without the use of any existing network infrastructure or centralized administration. Recently, there has been a tremendous growth in the sales of laptops, handheld computers, PDA and portable computers. These smaller computers nevertheless can be equipped with megabytes/gigabytes of disk storage, high-resolution color displays, pointing devices and wireless communications adapters. Moreover, since many of these small computers operate for hours with battery power, users are free to move without being constrained by wires. To support such type of scenario MANET has been designed. MANET has several characteristics such as, dynamic topologies, bandwidth-constrained, variable capacity links, energy-constrained operation and limited physical security. There are three types of routing protocols in MANET such as Proactive, Reactive, and Hybrid. In this paper, a detailed simulation based performance study and analysis is performed on these types of routing protocols over MANET. Ad Hoc On-Demand Distance Vector (AODV), and Dynamic MANET On-demand (DYMO) routing protocol (reactive), Optimized Link State Routing protocol (OLSR) (proactive) and Zone Routing Protocol (ZRP) is (hybrid) have been considered in this paper for the investigation and their relative performance is reported.

Joint path and spectrum diversity in cognitive radio ad-hoc networks

AbstractThe uncertain availability of the spectral resource imposes unique challenges in cognitive radio networks. One of the critical issues is to counteract the performance degradation experienced by cognitive users (CUs) due to the activity of primary users (PUs). Since the activity of PUs varies both in frequency and space domain, diversity techniques can represent an efficient way to address this issue. In this article, it is proposed to jointly exploit path and spectrum diversity for effective use of spectrum in cognitive radio ad-hoc networks (CRAHNs). By jointly exploiting both the diversities, CUs can switch dynamically to different paths and spectrum bands for communicating with each other in presence of frequency- and space-varying PU activity. This idea is adopted in a routing protocol, referred to as Dual Diversity Cognitive Ad-hoc Routing Protocol, and simulation results reveal the effectiveness of introducing joint path and spectrum diversity in CRAHNs.

Enabling drone communications with WiMAX Technology

With the popularity of winter tourism, the winter recreation activities have been increased day by day in alpine environments. However, large numbers of people and rescuers are injured and lost in this environment due to the avalanche accidents every year. Drone-based rescue systems are envisioned as a viable solution for saving lives in this hostile environment. To this aim, a European project named “Smart collaboration between Humans and ground-aErial Robots for imProving rescuing activities in Alpine environments (SHERPA)” has been launched with the objective to develop a mixed ground and aerial drone platform to support search and rescue activities in a real-world hostile scenarios. In this paper, we study the challenges of existing wireless technologies for enabling drone wireless communications in alpine environment. We extensively discuss about the positive and negative aspects of the standards according to the SHERPA network requirements. Then based on that, we choose Worldwide interoperability for Microwave Access network (WiMAX) as a suitable technology for drone communications in this environment. Finally, we present a brief discussion about the use of operating band for WiMAX and the implementation issues of SHERPA network. The outcomes of this research assist to achieve the goal of the SHERPA project.

Reliability Analysis of ZigBee Based Intra-Vehicle Wireless Sensor Networks

Reliability is one of the key issues in intra-vehicle wireless sensor networks, which is a promising research area due to the increasing demand of various safety and convenience applications in the vehicle. Most of the works about this mainly focus on wireless, sensor and computer networks. However, the reliability analysis on intra-vehicle wireless sensor networks is not similar to others because of the complex environment created by a large number of parts inside the vehicle. In this paper, we analyse the reliability for single link between a base station and a sensor node based on ZigBee standard. A robust system design can be achieved by utilizing the experimental analysis.

Big Data Reduction for a Smart City’s Critical Infrastructural Health Monitoring

Critical infrastructure monitoring is one of the most important applications of a smart city. The objective is to monitor the integrity of the structures (e.g., buildings, bridges) and detect and pinpoint the locations of possible events (e.g., damages, cracks). Regarding todays complex structures, collecting data using wireless sensor data over extensive vertical lengths creates enormous challenges. With a direct BS deployment, a big amount of data will accumulate to be relayed to the BS. As a result, traditional models and schemes developed for health monitoring are largely challenged by low-cost, quality-guaranteed, and real-time event monitoring. In this article, we propose BigReduce, a cloud based health monitoring application with an IoT framework that could cover most of the key infrastructures of a smart city under an umbrella and provide event monitoring. To reduce the burden of big data processing at the BS and enhance the quality of event detection, we integrate real-time data processing and intelligent decision making capabilities with BigReduce. Particularly, we provide two innovative schemes for health event monitoring so that an IoT sensor can use them locally; one is a big data reduction scheme, and the other is a decision making scheme. We believe that BigReduce will result in a remarkable performance in terms of data reduction, energy cost reduction, and the quality of monitoring.

Design of Wireless Sensor Network for Intra-vehicular Communications

The number of sensor nodes in the vehicle has increased significantly due to the increasing of different vehicular applications. Since, the wired architecture is not scalable and flexible because of the internal structure of the vehicle, therefore, there is an increasing level of appeal to design a system in which the wired connections to the sensor nodes are replaced with wireless links. Design a wireless sensor network inside the vehicle is more challenging to other networks, e.g., wireless, sensor and computer networks, because of the complex environment inside the vehicle. In this paper, we design a wireless sensor network for intra-vehicular communications. Firstly, we discuss about the link design between a base station and a sensor node and then we design a network scenario inside the vehicle for reliable communication. Finally, the performance is evaluated in terms of network reliability. The simulation results assist to design a robust system for intra-vehicular communications.

Link quality estimators for multi-hop mesh network

In this paper, the problem of estimating the link quality in mesh networks has been considered. Such a problem is a major task to develop an efficient network layer, since an accurate knowledge of the link qualities allows routing protocols to efficiently use neighbors as relays for multi-hop communications. In the last years, a number of link-quality aware routing metrics based on the packet delivery ratio have been proposed and analyzed. However, very few works have addressed the problem of correctly estimating the delivery ratio of a wireless link. Therefore, in this paper we resort to a 802.11b mesh network to carry on a performance comparison between two widely adopted delivery ratio estimators, namely the Simple Moving Average and the Exponentially Weighted Moving Average, and a recently proposed one based on the neural network paradigm.

Intergating Multiple Metrics to Improve the Performance of a Routing Protocol over Wireless Mesh Networks

Wireless Mesh Networks (WMNs) are dynamically self-organized and self-configured, with the nodes in the network automatically establishing an ad hoc network and preserving the mesh connectivity. There are several features which might help to design an efficient routing protocol suitable for wireless mesh networks such as improved performance metrics, link or path optimization, mobility management, scalability, cross-layer design etc. Since WMNs are permanent or semi-permanent network, an efficient and reliable path establishment is the core concern for such type of networks. By using the improved performance metrics, a reliable path can be established between source and destination. Minimum hop-count is the metric most commonly used by existing routing protocols. This approach implicitly assumes that links either work well or don’t work at all. While often true in wired networks, this is not a reasonable approximation in the wireless case; since many wireless links have intermediate loss ratios, interference problem, low throughput etc. For this reason, several performance metrics are already designed for WMNs such as Expected Transmission Count (ETX), Expected Transmission Time (ETT), Interference Aware Routing Metric (iAWARE), Link Type Aware (LTA) Metric, Success Probability Product (SPP) and so on. However, each individual routing metric consider some features and it is difficult to satisfy all the requirements of WMNs by using a single metric. Consequently, it is necessary to integrate multiple performance metrics into a routing protocol to attain optimal performance. This paper proposes a technique of integrating multiple routing metrics to improve the performance of a routing protocol. This technique is implemented in Ad hoc On-Demand Distance Vector (AODV) routing protocol and corresponding performance has been investigated in wireless mesh environment. Simulation results demonstrate significant performance improvement over standard AODV in WMNs.

Design a technique for minimizing unnecessary handoff in mobile wireless networks

Unnecessary handoff is one of the key issues in mobile wireless network, since it consumes the networks resources that degrades the performance of the network. Handoff appears when the Receive Signal Strength (RSS) of a mobile node becomes below threshold value (i.e., an acceptable level of RSS for ensuring communication). Subsequently, the mobile node starts scanning to discover a new RSS from neighbors Access Point (AP) to keep continuing the communication. However, traditional handoff algorithm is not accurate due to only depend on the RSS. It is affected by many factors (e.g., shadowing, scattering, reflection, etc.) that initiate unnecessary handoff decision. In this paper, a new technique is proposed to mitigate the unnecessary handoff. The simulation result confirms the effectiveness of the proposal.

Improved link repair technique for multicast routing in Wireless Mesh Network

Efficient multicasting over Wireless Mesh Network (WMN) is challenging due to dynamic and multi-hop wireless communication among multicast group members. Multicast Ad hoc On-Demand Distance Vector (MAODV) protocol is a tree based multicast routing protocol that enables dynamic, self-starting, multi-hop routing between participating mobile nodes wishing to join or participate in a multicast group in Wireless Mesh Network (WMN). The mobility of mobile nodes often causes link breakage in the tree-based protocols which sometime results in tree partitioning and poor performance. In MAODV, when a broken link is detected between two nodes on the multicast tree, the node downstream to the break is responsible for initiating the repair of the broken link. After link repair, it is likely that the previous distance between the nodes (nodes downstream to the link breakage) and the group leader will not remain same. The shortest path from the group leader to the nodes downstream to the node which initiates link breakage is not ensured. Moreover, if the node attempting to repair a tree link break does not receive a response after certain attempts, it assumes that the multicast tree is not repairable currently and this leads to tree partitioning. In this paper, an improved link repair technique is proposed which ensures shortest path from any node to the group leader. Simulation results demonstrate significant improvement in performance metrics compared to standard MAODV.