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Energy conservation is the main issue in wireless sensor networks. Many existing clustering protocols have been proposed to balance the energy consumption and maximize the battery lifetime of sensor nodes. However, these protocols suffer from the excessive overhead due to repetitive clustering resulting in high-energy consumption. In this paper, we propose energy-aware cluster-based routing protocol (ECRP) in which not only the cluster head (CH) role rotates based on energy around all cluster members until the end of network functioning to avoid frequent re-clustering, but also it can adapt the network topology change. Further, ECRP introduces a multi-hop routing algorithm so that the energy consumption is minimized and balanced. As well, a fault-tolerant mechanism is proposed to cope up with the failure of CHs and relay nodes. We perform extensive simulations on the proposed protocol using different network scenarios. The simulation results demonstrate the superiority of ECRP compared with recent and relevant existing protocols in terms of main performance metrics. [ABSTRACT FROM AUTHOR]

Fault resilient routing is a typical issue for underwater wireless sensor networks ( UWSNs ) due to contact of underwater creatures, mobility of nodes and natural disaster. In the existing studies, most of the researchers introduced routing scheme for routing the packets towards the base station through a cluster head. However, these schemes use static or mobile nodes for deployment, but nodes move from its original position to another position and get stuck in a particular region due to ocean current, natural disaster and environmental interference. Therefore, this leads to high energy depletion, link failure, disjoint path and overloaded data. To resolve this issue, we have proposed fault resilient routing based on moth flame optimization ( MFO ) scheme for transferring the packets towards the base station through autonomous underwater vehicles ( AUVs ). In this scheme, AUVs is used instead of cluster head to avoid the reclustering, overloading problem and it also feasible for large scale networks. There may be a disjoint path issue, so we have deployed additional mobile nodes with the help of AUVs within the network. Further, a novel fitness function is integrated with the MFO scheme to overcome the link failure problem. The proposed scheme is applied to select the best forwarding node for transmitting the packets towards the nearest AUVs using multi-hop acoustic links. In UWSNs , AUVs is placed to move the packets towards the BS from lower level to upper level. Performance evaluation of proposed scheme shows better result in terms of fault resilient, residual energy, network lifetime, packet delivery ratio and convergence rate than the existing scheme under the different network scenario. [ABSTRACT FROM AUTHOR]

The increasing usage of wireless sensor networks in human life is an indication of the high importance of this technology. Holes in wireless sensor networks are non-operating areas that can happen for a variety of reasons, like natural obstacles and disasters. Detection and packet routing in the presence of holes have always been the main challenges of facing this technology. As a result, most of the research on wireless sensor networks has been concerned with the problem of routing through bypassing routing holes. Considering the fact that the hole detection method for transmitting data in wireless sensor networks has a considerable impact on the energy consumption of the network, this paper attempts to provide a solution in the field of routing with the aim of increasing the network lifetime. In this method, considering networks with a dynamic hole, a distributed algorithm is proposed that can quickly determine and update the hole boundary. According to the hole, the packets are guided along an escape path around the hole which can improve and extend network lifetime. Results of experimental simulation are compared with the well-known and successful routing methods in the wireless sensor networks. This comparison shows that the proposed method reduces the dead nodes by at least 11% and 8% considering the effect of the time and the number of the nodes, in turn. Furthermore, the network lifetime has been improved by 2.71% based on the effect of the time and 1.47% based on the number of the nodes. [ABSTRACT FROM AUTHOR]

Multimedia transmission in wireless multimedia sensor network requires restricted quality of services (QoS) conditions. Where the resource-constrained nature of wireless multimedia sensor network (WMSNs) adds more challenges. Such a situation demands a routing strategy that can ensure QoS transmission and exploit the resources efficiently. At present, the single-path routing techniques cannot guarantee the end to end QoS requirements of video transmission causing the video quality degradation. Besides, the traditional network layers stack is not suitable for dynamic wireless sensor network environment, where important information is required from nonadjacent layers to enhance the routing decision. This paper proposes the design of cross-layer multipath routing (CLMR) scheme in order to ensure QoS and minimize energy consumption. CLMR is designed to determine the suitable multipath and to send the multimedia packets according to their importance. The cross-layer design between application, network and physical layers is adapted to obtain optimal routing decision. The simulation results show that the CLMR has a significant improvement in performance as compared to other similar existing protocols, where the obtained average delay with high delivery is less than 150 ms, while the energy consumption is reduced, and the PSNR values for the tested clips are more than 30 db. [ABSTRACT FROM AUTHOR]

In a wireless sensor network, one of the most important constraints on sensor nodes is their power source, which is a battery. Sensor nodes carry a limited and generally irreplaceable battery. When providing a routing protocol for WSNs, it is necessary to take the energy constraint of sensor nodes into consideration. In this paper, a new routing algorithm based on a mobile sink is proposed. In the proposed algorithm, data is forwarded from the sensor nodes to the sink, which moves on four determined paths, by using a virtual cellular structure. In this algorithm when the sink moves from one cell to another, the routing in the network can be updated with minimum energy consumption and delay. The simulation results show that the proposed algorithm is more efficient than similar ones. [ABSTRACT FROM AUTHOR]

Vehicular ad hoc network (VANET), a special type of mobile ad-hoc networks (MANETs), is characterized by a very high mobility. Due to the dynamic nature of vehicle nodes and unstable wireless links, the design of an efficient and effective routing scheme is serious challenging for VANETs. Thus, proposing a reliable routing protocol for important data dissemination is essential for VANETs. In this paper, a clustering-based routing protocol is introduced where nodes are clustered according to movement information such as node degree and velocity of vehicles by means of imperialist competitive algorithm. Then, the cluster head is selected by means of radial basis function neural network algorithm according to amount of free buffer space and expected transmission count. Simulation results indicated that the proposed scheme improves the other related algorithms in terms of the parameters of packet delivery rate, throughput and end-to-end delay. [ABSTRACT FROM AUTHOR]

In this article, we propose a novel routing algorithm for wireless sensor network, which achieves uniform energy depletion across all the nodes and thus leading to prolonged network lifetime. The proposed algorithm, divides the Region of Interest into virtual zones, each having some designated cluster head nodes. In the entire process, a node can either be a part of a cluster or it may remain as an independent entity. A non-cluster member transmits its data to next hop node using IRP-Intelligent Routing Process (based on the trade-off between the residual energy of itself as well as its neighbor, and the required energy to transmit packets to its neighbor). If on the transmission path, some cluster member is elected as a next hop, it rejects IRP and transmits the packets to cluster head, which later forwards them to sink (adopting multihop communication among cluster heads). Routing is not solely performed using clusters, rather they aid the overall routing process, hence this protocol is named as Cluster Aided Multipath Routing (CAMP). CAMP has been compared with various sensor network routing protocols, viz., LEACH, PEGASIS, DIRECT TRANSMISSION, CEED, and CBMR. It is found that the proposed algorithm outperformed them in network lifetime, energy consumption and coverage ratio. [ABSTRACT FROM AUTHOR]

Recently, Underwater Wireless Sensor Networks (UWSNs) has witnessed significant attention from both academia and industries in research and development, due to the growing number of applications for wide range of purposes including commercial, scientific, environmental and military. Some of the major applications include pollution monitoring, tactical surveillance, tsunami warnings and offshore exploration. Efficient communication among sensors in UWSNs is a challenging task due to the harsh environments and peculiar characteristics of UWSNs. Therefore, design of routing protocol for efficient communication among sensors and sink is one of the fundamental research themes in UWSNs. In this context, this paper proposes a location-free Reliable and Energy efficient Pressure-Based Routing (RE-PBR) protocol for UWSNs. RE-PBR considers three parameters including link quality, depth and residual energy for balancing energy consumption and reliable data delivery. Specifically, link quality is estimated using triangle metric method. A light weight information acquisition algorithm is developed for efficient knowledge discovery of the network. Multi-metric data forwarding algorithm is designed based on route cost calculation which utilizes residual energy and link quality. Simulations are carried out in NS-2 with Aqua-Sim package to evaluate the performance of RE-PBR. The performance of the proposed protocol is compared with the stat-of-the-art techniques: DBR and EEDBR. The comprehensive performance evaluation attests the benefit of RE-PBR as compared to the state-of-the-art techniques in terms of network lifetime, energy consumption, end-to-end delay and packet delivery ratio. [ABSTRACT FROM AUTHOR]

Delay tolerant networks (DTNs) are characterized by delay and intermittent connectivity. Satisfactory network functioning in a DTN relies heavily on co-ordination among participating nodes. However, in practice, such co-ordination cannot be taken for granted due to possible misbehaviour by relay nodes. Routing in a DTN is, therefore, vulnerable to various attacks, which adversely affect network performance. Several strategies have been proposed in the literature to alleviate such vulnerabilities-they vary widely in terms of throughput, detection time, overhead etc. One key challenge is to arrive at a tradeoff between detection time and overhead. We observe that the existing table-based reactive strategies to combat Denial-of-service (DoS) attacks in DTN suffer from two major drawbacks: high overhead and slow detection. In this paper, we propose three secure, light-weight and time-efficient routing algorithms for detecting DoS attacks (Blackhole and Grey-hole attacks) in the Spray & Focus routing protocol. The proposed algorithms are based on use of a small fraction of privileged (trusted) nodes. The first strategy, called TN, outperforms the existing table-based strategy with 20-30 % lesser detection time, 20-25 % higher malicious node detection and negligible overhead. The other two strategies, CTN_MI and CTN_RF explore the novel idea that trusted nodes are able to utilize each others' information/experience using their long range connectivity as and when available. Simulations performed using an enhanced ONE simulator reveals that investing in enabling connectivity among trusted nodes (as in CTN_RF) can have significant performance benefits. [ABSTRACT FROM AUTHOR]

In this paper, we propose SR3 (which means secure resilient reputation-based routing), a secure and resilient algorithm for convergecast routing in wireless sensor networks. SR3 uses lightweight cryptographic primitives to achieve data confidentiality and unforgeability. Security of SR3 has been proven formally using two verification tools: CryptoVerif and Scyther. We made simulations to show the resiliency of SR3 against various scenarios, where we mixed selective forwarding, blackhole, wormhole, and Sybil attacks. We compared our solution to several routing algorithms of the literature. Our results show that the resiliency accomplished by SR3 is drastically better than the one achieved by those protocols, especially when the network is sparse. Moreover, unlike previous solutions, SR3 self-adapts after compromised nodes suddenly change their behavior. [ABSTRACT FROM AUTHOR]

The characteristics of MANET such as decentralization, dynamic topology and openness are susceptible for security threats. To overcome the security threats and to provide a reliable network to transmit packets, a need for trust based routing arises. Moreover, the trust along with energy requirement on ad hoc on demand distance vector have paved way for the development of the newly proposed algorithm named as refined trust and energy based ad hoc on demand distance vector algorithm which is the refined form of the existing trust and energy based ad hoc on demand distance vector algorithms and the classical AODV. In this paper, the refinement parameter is the trust. Moreover, Bayesian probability is introduced in this paper for trust management due to its ability to handle uncertainty for obtaining the refined form of Trust calculation. The proposed algorithm routes the packets from the source to destination not through the shortest route but by selecting a reliable route which consumes low energy and trustful for sending the packets. The simulation results obtained from this work show that the proposed algorithm performs better than the existing algorithms in terms of Trust based routing and energy efficiency. [ABSTRACT FROM AUTHOR]

Owing to the growth in several applications, Wireless Mesh Networks (WMN) is emerging as a vital technology for future wireless networks. Wormhole attack is one of the major security threats, which can disturb majority of routing communications, even when placed strategically. Therefore, a technique that can find wormhole-free routes in the network is required. In order to achieve this, in this paper, we propose a Monitoring Technique for Wormhole-Free Routing and DoS Attack Defense in WMNs. Initially, finite state model is applied where the node keeps the information about its sender and neighborhood receiver. Then, wormhole-aware secure routing is implemented to find wormhole free routes in the network. Finally, the priority mechanism is applied where the data packets are transmitted based on their priority. Based on the finite state model and priority mechanism, the malicious or wormhole nodes in the network are removed. [ABSTRACT FROM AUTHOR]

Mobile Ad hoc Networks (MANET) is made up of mobile devices which form an infrastructure-less network. In MANET, the devices can change its location and configure itself at any time. Hence, there is a possibility for the network to be prone to abnormal network events due to certain factors like error in the links, overflow in the buffers, layers, and so forth. So, in this paper, a cross-layer based congestion detection and routing protocol is proposed using Fuzzy logic. In this protocol, whenever a network event occurs, the kind of event occurring is recognized in order to handle it accordingly. Next, the alternate routes for data transmission are determined by applying the concept of fuzzy logic on some of the critical factors. Based on the fuzzy inference rules, appropriate routes are selected and data messages are transmitted successfully. [ABSTRACT FROM AUTHOR]

In recent research, link stability is getting tremendous attention in mobile adhoc networks (MANETs), because of several impediments that occur in a reliable and robust network. Link stability metric is used to improve network performance in terms of end-to-end delay, data success delivery ratio (DSDR) and available route time (ART). Energy consumption, bandwidth and communication delay of major concern in ad hoc networks. A high mobility of MANET nodes reduces the reliability of network communication. In a dynamic networks, high mobility of the nodes makes it very difficult to predict the dynamic routing topology and hence cause route/link failures. Multicast in MANETs is an emerging trend that effectively improves the performance while lowering the energy consumption and bandwidth usage. Multicast routing protocol transmits a packet to multicast a group at a given time instant to achieve a better utilization of resources. In this paper, node mobility is considered to map better their movement in the network. So, the links with long active duration time can be identified as a stable link for route construction. Variation in signal strength is used to identify whether the direction of the node is towards or away from estimating node. We consider signal strength as QoS metric to calculate link stability for route construction. Efforts are made to identify the link with highly probable longer lifetime as the best suitable link between two consecutive nodes. We predict the movement time of nodes that define the route path to the node destination. Exata/cyber simulator is used for network simulation. The simulation results of the proposed routing protocol are compared with on-demand multicast routing protocol and E-ODMRP, which works on minimum hop count path. Analysis of our simulation results has shown improvement of various routing performance metrics such as DSDR, ART, routing overhead and packet drop ratio. [ABSTRACT FROM AUTHOR]

Routing in urban environment is a challenging task due to high mobility of vehicles in the network. Many existing routing protocols only consider density, link connectivity, delay, and shortest path information to send the data to the destination. In this paper, a routing protocol is proposed which uses the urban road network information such as multi-lane and flyover to send the data to the destination with a minimum packet forwarding delay. The next path for data forwarding is selected based on a path value calculated by the Road Side Unit for each path connected to a junction. This protocol uses Ground Vehicle to Ground Vehicle (GV2GV) communication, Flyover Vehicle to Flyover Vehicle (FV2FV) communication, and Flyover Vehicle to Ground Vehicle/Ground Vehicle to Flyover Vehicle (FV2GV/GV2FV) communication to enhance the routing performance. Simulation results show that proposed protocol performs better than P-GEDIR, GyTAR, A-STAR, and GSR routing protocols in terms of end-to-end delay, number of network gaps, and number of hops. [ABSTRACT FROM AUTHOR]

Due to the promising application of collecting information from remote or inaccessible location, wireless sensor networks pose big challenge for data routing to maximize the communication with more energy efficient. Literature presents different cluster-based energy aware routing protocol for maximizing the life time of sensor nodes. Accordingly, an energy efficient clustering mechanism, based on artificial bee colony algorithm and factional calculus is proposed in this paper to maximize the network energy and life time of nodes by optimally selecting cluster-head. The hybrid optimization algorithm called, multi-objective fractional artificial bee colony is developed to control the convergence rate of ABC with the newly designed fitness function which considered three objectives like, energy consumption, distance travelled and delays to minimize the overall objective. The performance of the proposed FABC-based cluster head selection is compared with LEACH, PSO and ABC-based routing using life time, and energy. The results proved that the proposed FABC maximizes the energy as well as life time of nodes as compared with existing protocols. [ABSTRACT FROM AUTHOR]

Routing in Vehicular Ad hoc Network (VANET) is a challenging task due to high mobility of vehicles. In this paper, a RVCloud routing protocol is proposed for VANET to send the data efficiently to the destination vehicle using cloud computing technology. In this protocol, vehicle beacon information is send to the cloud storage through the Road Side Unit (RSU). As vehicles have less storage and computing facility, the information of all the vehicles moving in the city is maintained by the cloud. Source vehicle sends the data to the destination by sending the data to the nearby RSU. After receiving the data, RSU sends a request to the cloud for an optimal RSU information, that takes minimum packet forwarding delay to send the data to the destination. Cloud provides location service by providing destination location and optimal RSU information. Then RSU sends the data to the optimal RSU using internet. By using the internet facility, packet forwarding delay and link disruption problem are reduced. Simulation results show that, RVCloud performs better than VehiCloud, P-GEDIR, GyTAR, A-STAR, and GSR routing protocols. [ABSTRACT FROM AUTHOR]

Due to the battery limitations, energy-efficient routing is one of the most important issues in WSNs. In this paper, a novel distributed clustering routing protocol (NODIC) is proposed. The algorithm makes three main contributions to literature. Firstly, a time-sharing approach for CH election is suggested differently from the studies in literature. The most effective parameters are combined in a time-sharing approach on the purpose of gaining the highest performance. Secondly, easy implementation and self-reliant decision of probabilistic schemes and the guarantee that iterative schemes issue about selecting the desired CHs are pieced together without using any of them. Finally, since CH decision is performed locally and dynamically, the clusters can make their decisions independently from the others. NODIC is compared with three common corresponding approaches in literature for various values of the number of nodes and under different traffic distributions. The algorithms are evaluated by using the number of living nodes and total energy consumptions per round. The results show that NODIC performs considerably better than the other approaches for all number of nodes and under all distributions up to 79 %. [ABSTRACT FROM AUTHOR]

Along with the development of the technologies of various kinds, wireless sensor networks are gradually entering into the practicalization phase. Therefore, whether its performance is good or not will directly affect the use of WSNs. Routing is one of the most important technologies. In addition, the routing performance is a significant part of the evaluation index system of wireless sensor networks. Energy efficiency is focused on in the traditional routing protocols, while quality of service (QoS) (i.e., delay, reliability, robustness) becomes important in practical application. Routing protocols should not only ensure the energy efficiency, but also realize QoS performances. As a consequence how to achieve the equilibrium between energy efficiency and other performances is the issue to be solved. In this paper, some performance trade-off mechanisms and methods that have existed in the routing protocols of wireless sensor networks are analyzed and summarized. At the same time, the related technical features of the routing protocols are mentioned, the purpose of which is to provide a better understanding of the current research issues within the field of performance trade-off mechanisms and to guide the researcher to develop the routing protocols with better performance in order to fulfill the actual requirements. [ABSTRACT FROM AUTHOR]

Routing protocols in vehicular ad hoc network (VANET) mainly depends on the correct information provided by the neighbor vehicles in the form of beacons. If the on board unit is soft faulty, it provides incorrect data and reduces the performance of the system. In this paper, a novel self soft fault detection based routing protocol is proposed for VANET in city environment to send the data quickly to the destination by detecting the soft faulty vehicles. The vehicle itself detects whether it is soft faulty or fault free by using the decisions made by the neighbor vehicles and exclude itself from the routing process. The data is forwarded through the fault free vehicles in a mostly connected path. The best path is selected at every junction by finding path values for the paths connected to the junction. The path with the minimum path value is selected as the next path through which the data is forwarded. The performance of the fault detection method is evaluated by fault detection rate and false alarm rate. Simulation results show that, proposed protocol performs better than GyTAR, A-STAR, P-GEDIR, and GSR routing protocols in terms of end-to-end delay, number of network gaps, and path length. [ABSTRACT FROM AUTHOR]

Routing the data efficiently in wireless sensor network (WSN) is the current area of research. Recently, many hybrid routing protocols have been proposed for WSNs. The key interest is on improving energy efficiency, network lifetime, deployment strategy, fault tolerance and latency. T-ANT clustering protocol is an efficient, scalable and robust data routing strategy. This protocol uses both hierarchical structure and biological inspiration. In this paper we investigate the effect of multi-path fading model on T-ANT clustering protocol and provide comparative study of results with the T-ANT protocol in isotropic model in a simulated environment on MATLAB platform. In particular, we are interested to investigate the effect of multi-path fading model on clustering fitness, cluster head election fitness and work load distribution among sensor nodes. The results show that T-ANT protocol in multi-path fading model performs little lower than the T-ANT protocol in isotropic model without affecting the clustering fitness properties. [ABSTRACT FROM AUTHOR]

Disasters create emergency situations and the services provided must be coordinated quickly via a communication network. Mobile adhoc networks (MANETs) are suited for ubiquitous communication during emergency rescue operations, since they do not rely on infrastructure. The route discovery process of on-demand routing protocols consumes too much bandwidth due to high routing overhead. Frequent route changes also results in frequent route computation process. Energy efficiency, quick response time, and scalability are equally important for routing in emergency MANETs. In this paper, we propose an energy efficient reactive protocol named Weighted-CDSR for routing in such situations. This protocol selects a subset of network nodes named Maximum Weighted Minimum Connected Dominating Set ( MWMCDS) based on weight, which consists of link stability, mobility and energy. The MWMCDS provides the overall network control and data forwarding support. In this protocol, for every two nodes u and v in the network there exists a path between u and v such that all intermediate nodes belong to MWMCDS. Incorporating route stability into routing reduces the frequency of route failures and sustains network operations over an extended period of time. With fewer nodes providing overall network control and data forwarding support, the proposed protocol creates less interference and consumes less energy. The simulation results show that the proposed protocol is superior to other protocols in terms of packet delivery ratio, control message overhead, transmission delay and energy consumption. [ABSTRACT FROM AUTHOR]

A mobile ad hoc network (MANET) does not have traffic concentration points such as gateway or access points which perform behaviour monitoring of individual nodes. Therefore, maintaining the network function for the normal nodes when other nodes do not forward and route properly is a big challenge. One of the significant attacks in ad hoc network is wormhole attack. In this wormhole attack, the adversary disrupts ad hoc routing protocols using higher bandwidth and lower-latency links. Wormhole attack is more hidden in character and tougher to detect. So, it is necessary to use mechanisms to avoid attacking nodes which can disclose communication among unauthorized nodes in ad hoc networks. Mechanisms to detect and punish such attacking nodes are the only solution to solve this problem. Those mechanisms are known as intrusion detection systems (IDS). In this paper, the suggested biological based artificial intrusion detection system (BAIDS) include hybrid negative selection algorithm (HNSA) detectors in the local and broad detection subsection to detect anomalies in ad hoc network. In addition to that, response will be issued to take action over the misbehaving nodes. These detectors employed in BAIDS are capable of discriminating well behaving nodes from attacking nodes with a good level of accuracy in a MANET environment. The performance of BAIDS in detecting wormhole attacks in the background of DSR, AODV and DSDV routing protocols is also evaluated using Qualnet v 5.2 network simulator. Detection rate, false alarm rate, packet delivery ratio, routing overhead are used as metrics to compare the performance of HNSA and the BAIDS technique. [ABSTRACT FROM AUTHOR]

The performance modeling study of Delay-Tolerant Network routing, in general, assumes the nodes to be homogeneous (in terms of features such as the coverage range) and uncompromised (in terms of forwarding messages). However, in realistic settings this may not be the case. The routing performance modeling of such realistic scenarios that involve multifariously-featured and egotistic nodes would be interesting and insightful. To this end, in this paper, we analytically model the routing behavior of such nodes using Ordinary Differential Equations for two different routing protocols namely, Epidemic Routing and Two-Hop Routing. Furthermore, we also study the degradation in the routing performance caused by an increase in the fraction of selfish nodes present in the heterogeneous node population. The proposed analytical model is validated via extensive simulations. [ABSTRACT FROM AUTHOR]

We present a new approach to secure routing in mobile ad-hoc networks based solely on the relative transmission times of overhead packets. Unlike most previous works aimed at securing route computation, we eliminate a key vulnerability (explicitly stated routing metrics) altogether. We introduce the Secure Time-Ordered routing Protocol (STOP), which uses time-based orderings to ensure the establishment of multiple loop-free paths between a source and a destination. STOP is the first routing protocol to use performance-based path selection without source routing, path vectors, or complete topology information, making it far more efficient that similar approaches. We prove that adversaries cannot take any action to manipulate the time-based ordering so as to unfairly gain control of the forwarding topology and, by design, nodes which drop data packets will be avoided. Furthermore, at convergence, traffic load is evenly distributed over the well-performing paths, so adversaries cannot gain complete control over the data flow through temporary good behavior. Simulation results show that the countermeasures in STOP are effective against a variety of attacks from independent and colluding adversaries, and that this improved security does not come at the expense of routing performance. [ABSTRACT FROM AUTHOR]

new approach for routing protocols operating in MANETs is presented in which flooding is not required to establish paths from sources to destinations on demand in MANETs of moderate size. The concept of ordered walk is introduced as a depth-first search (DFS) that does not rely on geographical or virtual coordinate information and is much more efficient than mere random walks. The benefits of using DFS as the building block of the signaling in MANET routing protocols are exemplified by the introduction of the Ordered Walk Search Algorithm (OSA), which is used as part of the proposed Ordered Walk with Learning (OWL) protocol. OWL integrates OSA with the learning of paths from prior successful and failed attempts, and performs one or multiple concurrent ordered walks to search for destinations. Simulation experiments are used to compare the performance of OWL against that of well-known MANET routing protocols based on BFS (e.g., OLSR and AODV). The results show that OWL can achieve a performance comparable to traditional protocols that rely on some form of flooding of link states or network-wide dissemination of distance information in terms of packet delivery ratios and average end-to-end delays, while incurring up to ten times less overhead than AODV. [ABSTRACT FROM AUTHOR]

The increasing use of wireless networks and the constant miniaturization of electrical devices has empowered the development of Wireless Body Area Networks (WBANs). In these networks various sensors are attached on clothing or on the body or even implanted under the skin. The wireless nature of the network and the wide variety of sensors offer numerous new, practical and innovative applications to improve health care and the Quality of Life. The sensors of a WBAN measure for example the heartbeat, the body temperature or record a prolonged electrocardiogram. Using a WBAN, the patient experiences a greater physical mobility and is no longer compelled to stay in the hospital. This paper offers a survey of the concept of Wireless Body Area Networks. First, we focus on some applications with special interest in patient monitoring. Then the communication in a WBAN and its positioning between the different technologies is discussed. An overview of the current research on the physical layer, existing MAC and network protocols is given. Further, cross layer and quality of service is discussed. As WBANs are placed on the human body and often transport private data, security is also considered. An overview of current and past projects is given. Finally, the open research issues and challenges are pointed out. [ABSTRACT FROM AUTHOR]