Search

Recently, Wireless Sensor Networks (WSNs) grow to be one of the dominant technology trends; new needs are continuously emerging and demanding more complex constraints in a duty cycle, such as extend the life time communication . The MAC layer plays a crucial role in these networks; it controls the communication module and manages the medium sharing. In this work we use OSC-MAC tackles combining with the performance of cooperative transmission (CT) in multi-hop WSN and the Wi-Lem technology

In this paper, we describe the impact of black-hole attack on LEACH protocol and direct transmission using C++ language and some tools from ns3. The results are showed in the number of packet received by the base station; and we try to protect the network from this type of network using the minimum energy and less modification in the original algorithm.

Wireless Sensor Network (wsn) performances have progressed over the last few years, aiming at expanding the lifetime nodes. Among the important studied parts on wsn is the congestion degree that can be identified by several algorithms such as HTAP (Hierarchical Tree Alternative Path), which is the target in the current study. It is important to mention that besides the variations observed between the four HTAP deployments of this classical algorithm ( detailed on the rest of paper ) , there is a possibility that other factors, such as energy efficiency, network lifetime are affected by the node displacements in the HTAP phases ( in case of the route change caused by the isolated dead nodes to the sink ) , which give the idea to reduce this undesirable problem by designing a new algorithm called Hierarchical Tree Congestion degree with Speed sending and Sum costs link Quality (HTCSLQ) by reducing the energy consumption , according to the choice of the lower Congestion degree , optimal Speed sending and Sum costs link Quality values from the source to destination.

Today the world is moving towards wireless system. Wireless networks are gaining popularity to its peak today, as the users want wireless connectivity irrespective of their geographic position. Vehicular ad-hoc networks (VANETs) are considered to be the special application of infrastructure-less wireless Mobile ad-hoc network (MANET). In these networks, vehicles are used as nodes. In this paper, we examine and analyze the performance of Ad-hoc On-Demand (AODV), Dynamic Source Routing (DSR) and Destination-Sequenced Distance Vector (DSDV) routing in terms of Packet Delivery Ratio, Average End to End Delay, Latency and Throughput. The objective of this study is to find the best routing protocol over all circumstances. Based on our validated results, AODV performs the best among all evaluated protocols.

In wired networks there are different physical devices routing the traffic centrally. By consequence, we can create paths in the network by using multiple management rules, but in Ad-Hoc network nodes this work must be done in an autonomous way. For that there are three types of routing protocol proactive, reactive and hybrid. The first one continuously calculates the possible paths to be available at the time of transmission. The second one creates the roads only when they are needed. And the last one is a combination between the two methods. In this study we will focus on three routing protocols AODV, OLSR and ZRP; and compare their performance in terms of loss packets and energy efficient.

In mobile Ad-Hoc networks, each node of the network must contribute in the process of communication and routing. However this contribution can expose the network to several types of attackers. In this paper, we study the impact of one attack called BLACK-HOLE, on Ad hoc On-Demand Distance Vector routing protocol. In this attack a malicious node can be placed between two or several nodes, and begin dropping all packets from a source and breaking communications between nodes. The vulnerability of the route discovery packets is exploited by the attacker with a simple modification in the routing protocol, in order to control all the traffic between nodes. In this study we simulate the attack with NS2, taking into account the mobility of the network and the attacker, the position of the attacker and finally the number of the attackers. We will also see the impact of this attack in a higher number of loss packet compared with AODV in normal situation.