Prolonging network lifetime has become a real challenge in Mobile Wireless Sensor Networks (MWSNs) as sensors have limited energy. In this paper, we propose a Cluster-based Energy-efficient Scheme (CES) for electing a cluster-head to evenly distribute energy consumption in the overall network and therefore obtain a longer network lifetime. In CES, each sensor calculates its weight based on k-density, residual energy and mobility and then broadcasts it to its 2-hop neighborhood. The sensor node with the greatest weight in its 2-hop neighborhood will become the cluster-head and its neighboring sensors will then join it. We performed simulations to illustrate the effects of sensor mobility on LEACH and LEACH-C's performance. Unfortunately, our findings showed that sensor mobility had a significant impact on both protocols' performance, but CES provided good results in terms of the amount of data packets received at the sink when compared with LEACH and LEACH-C.
We propose a method to manage transmission power in nodes belonging to a wireless sensor network (WSN). The scenario contem- plates uncoordinated communications using impulse radio ultra wide- band (IR-UWB). Transmission power is controlled according to the sta- tistical nature of the multiple access interference (MAI) produced by the nodes in the close vicinity of the communicating nodes. The statistical nature of the MAI is a function of the node population density within the area of coverage of the WSN. We show that when the node population density is high enough transmission power savings are possible.
Overlay networks are becoming widely used for delivering content, since they provide effective and reliable services that are not otherwise available. However, overlay management systems face the challenges of increased complexity and heterogeneity due to the numerous entities that are involved in realizing overlay services. We believe that autonomic management is a key solution for dealing with the complexity of overlay management. In this paper, a management architecture for service specific overlay networks is proposed. Overlays are viewed as a dynamic organization for self-management in which self-interested nodes can join or leave according to their goals. The objective of this architecture is to create autonomic overlays that are driven by different levels of policies. Policies are generated at different levels of the autonomic management hierarchy and enforced on the fly. The proposed autonomic management dynamically adapts the behavior of the overlay network to the preferences of the user, network, and service providers. A description of our novel achitecture that addresses these challenges is presented.
Power savings are nowadays crucial in embedded system contexts such as Wireless Sensor Networks (WSN) in order to increase the lifetime of sensor nodes. In this paper, we propose a new hardware structure called "Power-On Controller" (POC) for applying advanced control strategies for the "idle to active" node state transition. The proposed POC allows an optimization of power control by using event accumulation and spatial selectivity mechanisms. These new features allow to reduce the dynamic power consumption of roughly 60% compared to state-of-the-art power management solutions for a typical WSN applicative context, without altering the quality of service. The POC structure can be easily integrated in any sensor node based on system-on-chip design.
Technological advances in miniaturization and wireless networking have enabled the utilization of distributed wireless sensor networks (WSN) in many applications. WSNs often use clustering as a means of achieving scalable and efficient communications. Cluster head nodes are of increased importance in these network topologies because they are both communication and coordination hubs. Much of the research into maximizing WSN longevity and efficiency focuses on dynamically clustering the network according to the residual energy contained within each node. This is a result of the commonly held assumption that battery depletion is the primary cause of node failure. In this work, we consider that there are applications in which threats may significantly impact node survival. In order to cope with these applications, we present a threat-aware clustering algorithm, extending the Hybrid Energy Efficient Distributed clustering algorithm (HEED) that minimizes the exposure of cluster heads to threats in the network environment. Simulation results indicate that our extended threat-aware HEED, or t-HEED, improves both the longevity and energy efficiency of a WSN while incurring minimal additional overhead. Our research demonstrates and motivates the need for a general framework for adaptive context-aware clustering in WSNs.
Networks with frequent and long duration partitions prevent common Internet protocols from working successfully. For protocols to work properly in these Delay/Disruption Tolerant Networks (DTNs), a new protocol layer was proposed that acts on top of the transport layer for the end-to-end exchange of messages (called bundles) taking advantage of scheduled, predicted, opportunistic or permanent connectivity. In this paper, we propose and evaluate a multicast extension to the DTN's unicast PROPHET protocol. A multicast protocol is useful to reduce the number of copies of packets when they are sent to multiple destinations. We show by simulation that by using just one byte for transferring mobility information between nodes, a good clue about the region where mobile nodes are is given, which can be used by the multicast protocol to decide where to forward messages. Additionally, we show that if the number of contacts between nodes is above a minimum threshold, a pseudo multicast tree will exist, multicast works efficiently and message replications are minimized.
Wireless sensor and ad hoc networks are gaining a lot of attention in research lately due to their importance in enabling mobile wireless nodes to communicate without any predetermined infrastructure. Routing protocol in wireless sensor and ad hoc networks discover a multi-hop route between source and destination nodes. This paper presents RAS: a Reliable routing protocol for wireless Ad hoc and Sensor networks. In the RAS protocol, increased reliability is achieved by the maintenance of a reliability factor by the nodes. The value of this factor is increased when nodes participate successfully in data transmissions. This is determined through the use of positive and passive acknowledgements. During the path discovery process, an intermediate node only extends the request message to nodes that have a minimal reliability factor which is specified by the source. Additional optimizations are included in order to increase the efficiency and performance of the network.
Wireless Sensor Networks are prone to many security attacks. The most complex among them is the node compromise attack. Networks enhanced with services like aggregation and security require a different intrusion detection mechanism than the generally used solutions and there is a possibility of a compromised node producing false intrusion detection alarms. Therefore we need suitable mechanisms to detect intrusion and to securely confirm the same. We propose two major schemes: 1) a post-deployment key distribution based permanent key establishment scheme 2) two on-the-fly key establishment schemes. The simulation results and analysis show that on-the-fly schemes are better suited for intrusion confirmation in energy constrained sensor networks. A simple and practical intrusion defense scheme also is suggested.
Wireless sensor actor networks (WSANs) consist of a large number of resource-constrained nodes (sensors) and a small number of powerful resource rich nodes (actors). This paper investigates the case where sensors are organized into clusters and mobile actors are used for maintaining an energy efficient topology by periodically manipulating their geographical position. We present an elegant technique that allows actor nodes to find an optimal geographical location with respect to their associated cluster heads such that the overall energy consumption is minimized. The simulation results demonstrate that the technique proposed in this paper significantly minimizes energy Consumption and extends the network lifetime compared with traditional cluster-based WSN deployments.
Recently, wireless sensor networks (WSNs) have attracted attentions of many researchers since they can be used for wide range of applications such as environmental monitoring, security, disaster prevention, environmental control in office buildings, and precision agriculture. Control mechanisms for WSNs should adapt to a variety of communication patterns which reflect application requirements and the situation. In this paper, we propose ARCP (Ant-based rendezvous communication protocol), a novel communication protocol for WSNs. ARCP is designed to be adaptive to a variety of communication patterns by taking the rendezvous-based approach, where sensor data are collected and delivered through nodes marked as rendezvous points. At the same time, ARCP acquires robustness to failures and scalability with respect to network size by adopting AntHocNet, which is an ad-hoc routing protocol inspired by foraging behavior of ants. Through simulation experiments, we show that ARCP outperforms existing communication protocols in adaptability, robustness, and scalability.
A WSN (Wireless Sensor Networks) consists of a large number of sensor nodes. Each sensor node has limited battery, small storage, and short radio range. Many researchers have proposed various methods to reduce energy consumption in sensor nodes, since it is difficult to replace sensor node power sources. Generally, a sensor node consumes its energy during processing, receiving.. transmitting and overhearing of messages that are directed to other nodes. Among those, overhearing is not necessary for correct operation of sensor networks. In this paper we propose a new synchronized wakeup scheme to reduce the overhearing energy consumption using different wakeup time scheduling for extending sensor network lifetime. The results of our simulation show that there is a trade-off between reducing overhearing energy and delay time. Therefore we propose Double Trees Structure, called DTS, having two routing trees, one based on Short Rings Topology and the other on Long Rings Topology. DTS has multi routing paths from base station to children nodes. If a node which is on the next routing path does not wakeup in time to receive the data, the sender node selects another path to connect to the destination. We can save the wait time until the next destination node wakes up. In the simulation result, our wakeup scheduling reduces overhearing energy consumption more than the S-MAC protocol. Using the double trees structure reduces the delay time.
Ad hoc and sensor networks is a new area of research which is rapidly growing due to the development of new technologies in inexpensive sensors. These electronic devices have increased capabilities in processing speed, memory, communication and networking [21][22]. Such sensor networks have a vast amount of applications including environmental monitoring, military, ecology, agriculture, inventory control, robotics and health care. This paper discusses the issues and challenges in the use of this new and very promising technology in the protection and monitoring of the critical and essential infrastructures of pipelines carrying oil, gas, water, and other important resources. The paper presents an architectural model that can be used to provide this monitoring and control functions. The model includes an overview of networking and routing protocols that can be used to provide the necessary communications. In addition, the paper provides discussions and recommendations concerning network reliability and the use of different wireless sensor technologies and protocols.
In this research, we have suggested the Localization Algorithm using Probable Filtering Schema of RSSI without additional hardwares. The existing method has been filtering with only average and feedback of received RSSI values. This method was not considering about the variation of RSSI when obstacles are moving at indoor environment. In this research, we have suggested the probable filtering algorithm which is considered factors of errors at indoor environment and we have demonstrated the superiority of this algorithm through the examination. It presents 14.66
In this paper, we present an security protocol for Wireless Sensor Networks (WSNs). It is based on the forward and backward property of RC4 states and achieves data confidentiality, data authentication, data integrity, and data freshness with low overhead and simple operation. Furthermore, an RC4-based hash function for the generation of Message Authentication Code (MAC) is presented. The proposed protocol is an ideal solution for wireless sensor networks and other resource-constrained devices where the communication nodes have limited power resources and computational capabilities, and can be widely used in the applications of one-to-one communications as well as broadcasting and multicasting.
Many works related with mobile and ad-hoc networks routing protocols present new proposals with better or enhanced features, others Just compare them or present an application environment, but this work tries to give another point of view. Why don't we see the network as a whole and split it intro groups to give better performance to the network regardless of the used routing protocol?. First, we will demonstrate, through simulations, that grouping nodes in a mobile and ad-hoc networks improves the whole network by diminishing the average network delay and also the routing traffic received by the nodes. Then, we will show which one of the actual fully standardized protocols (DSR [1], AODV [2] and OLSR [3]) gives better performance to the whole network when there are groups of nodes. This paper starts a new research line and urges the researchers to think on it and design group-based protocols.
A wireless sensor network for automatic meter reading needs to satisfy two contradicting requirements, i.e., long lifetime and prompt detection and notification of emergency. We propose a sensor network protocol for this purpose, in which sensor nodes operate on a low duty cycle while the latency of transmission is guaranteed to be less than a certain bound. In this protocol, each node is assigned a time slot in which it receives messages from other nodes. To accomplish slot assignment where nodes further from a BS are assigned earlier time slots for a packet to be transmitted to the BS in one cycle, we propose a slot assignment function with which a node can determine its own slot in a distributed way. We explore several slot assignment functions to find one which gives low and homogeneous contention over a grid network. The simulation results show that our protocol performs well close to the optimal case.
Early researches focused on the security of homogenous sensor networks. However, recent works have demonstrated that the presence of heterogeneous sensor nodes gives better performance than homogenous ones in terms of energy consumptions, storage overhead, and network connectivity. In this paper, we propose a hierarchical key management scheme named HERO which is based on random key pre-distribution. HERO aims to construct a secure tree instead of complete connected graph as in existing schemes. Thanks to this realistic assumption, Our key management scheme reduces considerably the number of pre-loaded keys assigned to each node while maintaining high security level at the same time. The preliminary simulation results using TOSSIM demonstrates that our scheme outperforms existing ones with respect to storage overhead.
The reliability of communication can be enhanced by increasing the network connectivity. Topology control and node sleep scheduling are used to reduce the energy consumption. This paper considers the problem of maintaining k-connectivity of WSN at minimum energy level while keeping only a subset of sensor nodes active to save energy. In our proposed scheme, each node is assumed to have multiple power levels and neighbor proximity not exact location information is adopted. Firstly the network partition is attained by power based clustering, and next nodes are divided into equivalent classes according to the role of data forwarding to different adjacent clusters. Then Node Scheduling and Power Adjustment (NSPA) algorithm selects a subset of nodes with different power levels to construct the local minimum energy graph while maintaining network connectivity. If the number of intra-cluster nodes which have adjacent clusters exceeds a certain threshold, k-NSPA is employed. Finally, a k-connected topology can be obtained. The simulation shows that our scheme can obtain the redundant nodes while maintaining network k-connected and it is more energy efficient compared with previous work.
In wireless ad hoc networks, nodes are both routers and terminals, and they have to cooperate to communicate. Cooperation at the network layer means routing (finding a path for a packet), and forwarding (relaying packets for others). However, because wireless nodes are usually constrained by limited power and computational resources, a selfish node may be unwilling to spend its resources in forwarding packets that are not of its direct interest, even though it expects other nodes to forward its packets to the destination. In this paper, we propose a game-theoretic model to facilitate the study of the non-cooperative behaviors in wireless ad hoc networks and analyze incentive schemes to motivate cooperation among wireless ad hoc network nodes to achieve a mutually beneficial networking result.
A Wireless Sensor and Actor Network (WSAN) is composed of sensor and actor nodes distributed in a geographic area of interest; the sensors are involved in monitoring the physical environment, while the actors can execute a designated task in accordance to the data collected and reported by the sensors during an event. To achieve a balanced performance, a WSAN architecture must implement an efficient cooperative communication strategy to allow the nodes to collaborate in the optimal assignment of resources and to execute tasks with the lowest possible delay. Such collaboration must take place by exchanging information and generating negotiated decisions while trying to extend the WSAN lifetime. The main contribution of this work is the proposal of a coordination mechanism taxonomy for WSANs; this taxonomy provides a framework for the classification of coordination mechanisms designed for WSAN environments. Based on this taxonomy, a comparative analysis is presented to study some of the most representative coordination mechanisms proposed in the area of WSANs up to this date.
