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Delay tolerant networks (DTNs) is a network evolved from mobile networks. Differing from the traditional network, which has a stable end‐to‐end transmission path, DTNs are sparse and intermittently connected mobile ad hoc network, which are widely used in harsh environments, such as battlefields, seabed, space communication networks, and so on. In DTNs, intermittent connectivity, partitioned network, long delays and node mobility characteristics make the network fail to communicate frequently, therefore, how to successfully forward the message is of extreme importance. Up to now, almost all the traditional models in DTNs use the store‐carry‐forward method. This paper proposes a novel clustered DTN routing model based on sensing node relationship strength. The routing mechanism takes advantage of the number of other nodes encountered by the nodes in the process of movement and the changes in the number of nodes to calculate the strength of the relationship between nodes, and clusters DTN routing according to the strength of the relationship between nodes. Moreover, the relationship between nodes in a cluster and other clusters is used to transmit messages between clusters, and messages are transmitted within clusters according to the strength of the relationship between nodes. Simulation results show that the routing mechanism not only increases the success rate of message transmission, but also reduces the transmission delay of messages and improves network performance. [ABSTRACT FROM AUTHOR]

In unmanned aerial vehicle ad‐hoc network (UANET), the node speed of unmanned aerial vehicles (UAVs) may reach up to 400 km/h. The fast or slow movement of UAV nodes leads to different speeds of topology change of the nodes. Traditional optimized link state routing (OLSR) protocol cannot adaptively adjust the routing update period when the network topology changes, which may lead to the nodes calculating incorrect routing tables. This increases the average end‐to‐end delay and packet loss rate for packet transmission. To enhance the adaptability of OLSR routing protocol to network topology changes, this paper proposes a multi‐agent independent deep deterministic policy gradient‐OLSR (MA‐IDDPG‐OLSR) routing protocol based on distributed multi‐agent reinforcement learning. The protocol deploys DDPG algorithm on each UAV node, and each UAV node adaptively adjusts the Hello and TC message sending intervals, according to the one‐hop neighbouring nodes as well as its own state. Simulation results show that the proposed protocol is able to improve the throughput and reduce the packet loss rate as compared to traditional AODV, GRP, OLSR, and distributed multiple‐agent independent proximal policy optimization‐OLSR (MA‐IPPO‐OLSR), distributed multiple‐agent independent twin delayed deep deterministic policy gradient‐OLSR (MA‐ITD3‐OLSR) routing protocols. Since MA‐IDDPG‐OLSR relies only on local information, there is a minor performance degradation in MA‐IDDPG‐OLSR compared to centralized single‐agent DQN‐OLSR routing protocol. But it is more suitable to a completely distributed UAV network without a centralized node. [ABSTRACT FROM AUTHOR]

Processing queries in wireless sensor networks causes quality of service challenges such as data latency and validity. In fact, this paper is going to shed light on identifying the right trade‐off between latency and the freshness of the data. For this purpose, a fuzzy logic‐based decision‐making system that assigns incoming queries either to the sensor network, where the queries are waiting to be processed into a queue, or a central database which provides stored and potentially stale data or to a cache server which in turn provides acceptable latency and recent data, is provided. Thus, a new rule‐based system decision is introduced, that minimizes the request latency and returns the most recent data. In addition, a comparison between the approach and other work that is restricted to the database server and sensor network with no focus on the caching server is provided. This paper is going to carry on with the theory of Markov Chain which is more complicated compared to the fuzzy logic system. This approach is confirmed in the basis of an experience is developed with python. [ABSTRACT FROM AUTHOR]

Summary The cluster networking protocols are the roots that embed intelligent decision‐making and enhance the lifespan of wireless sensor networks (WSNs). Wireless sensors with limited capabilities face several challenges due to the heterogeneous application environments. Especially, the mobility‐incorporated sensors in most situations trouble the cluster network's robustness. Many cluster networking protocols have been presented in the past to enhance the network lifespan and data delivery ratio. However, they lack a dedicated and efficient mechanism for mobility assistance, an adequate cluster management process and cluster head selection criteria. To overcome these issues and for the uniform energy load distribution, we propose a mobility‐compatible cache controlled cluster networking protocol (MC‐CCCNP) in this paper. It is an energy‐efficient cluster networking protocol that supports sensor movement. Network resource management and routing are controlled distributively by an optimal number of cache nodes. It defines a new strategy for cache node deployment based on neighbour density as well as a weight formula for cluster head selection and cluster formation based on the residual energy, the distance to the base station and the node velocity. It also includes techniques for detaching and reconnecting a mobile node to an appropriate cluster cache if it crosses the cluster boundary. We simulate and compare the performance of our protocol with the centralised energy‐efficient clustering routing, energy‐efficient mobility‐based cluster head selection protocol and dual tier cluster‐based routing protocols over different network configurations with varying mobility, scalability and heterogeneity. The MC‐CCCNP showed remarkable improvements in energy utilisation uniformity and energy consumption. With the improved network lifespan, it also maintains a higher data throughput rate of 95% or more in almost all network configurations. [ABSTRACT FROM AUTHOR]

Summary: The main aim of this paper is to address the problem of redundant broadcast packets using the extension of rough set concept. In general, a rough set is a mathematical tool for dealing with issues of uncertainty. In MANET, mobile nodes are moving from one place to another place in a simulation environment; hence, it creates uncertainty issues. Due to the fast mobility of mobile nodes, network metrics such as bandwidth and hop count vary. The findings were useful in identifying and improving the network's performance. The proposed NRS‐based route selection approach has been compared with conventional techniques such as rough set, covering rough set (CRS). The reduced control packets are obtained using pruning concept based on selection of one‐hop and two‐hop nodes. Eventually, the proposed approach proved that it attains a higher throughput (85%), reducing the route request packets (3406) and delay of data transmission (0.02274 s). Also, two well‐known ad hoc routing protocols were used such as Dynamic Source Routing (DSR) and Ad Hoc On‐Demand Distance Vector (AODV) protocols. [ABSTRACT FROM AUTHOR]

Summary: A routing protocol for cognitive radio ad hoc networks (CRAHNs), namely, primary user supported routing (PSR) is demonstrated in this research. Unlike existing routing protocols for CRAHN, where routing of cognitive users (CUs) is accomplished within CUs, in this proposed protocol, some of the primary users (PUs) support CUs to communicate, by forwarding CU packets. This service provided by PU is of voluntary nature. However, such assistance shall be provided by the PUs, only when they are idle, thereby, preserving the principles of cognitive radio networks (CRNs), which indicates that the operation of PU should not be disturbed by the CU activities. The proposed work is compared with cognitive ad hoc on‐demand distance vector (CAODV) protocol. The performance parameters considered are routing overhead, rate of loss of packets, and e2e packet delay. PSR outperforms CAODV in all these performance parameters. There has been on average 26.25% improvement in routing overhead, 34.12% decrease in loss, and 27.01% improvement in e2e delivery in the proposed PSR. [ABSTRACT FROM AUTHOR]

Wireless sensor networks (WSNs) are made of spatially distributed autonomous sensors, which cooperate to monitor physical or environmental parameters and to deliver such data to one or more data sinks. A promising field of application of WSNs is planetary exploration, characterized by a continuous monitoring of the surface to have clear notion of planet conditions and prepare for future manned missions. The potentially large size of the region to be monitored and the line-of-sight limitations (as, for instance, on the Moon, which is the case study discussed in the paper) hamper the possibility of having 1-hop sensor-sink communications. Therefore, to allow sensed data to reach the sink(s), the sensors must be able to create and maintain a multi-hop ad hoc network. This paper proposes an ad hoc routing algorithm applicable to WSNs for planetary exploration, aiming at (i) assuring any-cast communications with multiple data sinks, (ii) minimizing the control overhead for routing maintenance, (iii) being light in terms of memory/computational requirements, to be installed into low-power and low-memory/processing devices, (iv) being rapid to reconfigure in the presence of node failures and (v) optimizing the choice of the paths, to achieve energy balancing and saving. Extensive simulations show the efficiency of the proposed approach. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The performance of backoff scheme plays an important role in designing efficient Medium Access Protocols for ad hoc networks. In this paper, we propose an adaptive backoff scheme and evaluate the performance of the proposed scheme for ad hoc networks. The backoff mechanism devised by us grants a node access to the channel based on its probability of collision for a transmitted frame in comparison to the nodes in the two-hop contention area. We use both an analytical model and simulation experiments to evaluate the performance of our adaptive backoff mechanism in an ad hoc network. The results show that our protocol exhibits a significant improvement in power saving, end-to-end goodput, packet delivery ratio, and hop-put, compared with the existing IEEE 802.11 DCF. Copyright © 2010 John Wiley & Sons, Ltd. In this paper, we propose an adaptive backoff scheme and evaluate the performance of the proposed scheme for ad hoc networks. The backoff mechanism devised by us grants a node access to the channel based on its probability of collision for a transmitted frame in comparison to those of nodes in the two-hop contention area. We use both an analytical model and simulation experiments to evaluate the performance of our adaptive backoff mechanism in an ad hoc network. The results show that our protocol exhibits a significant improvement in power saving, end-to-end goodput, packet delivery ratio, and hop put, compared to the existing IEEE 802.11 DCF. Copyright © 2010 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The messages in vehicular ad hoc networks (VANET) are vulnerable to attack in the open wireless environment. Group communication in VANET is receiving more attention, which confronts many security issues. First, only users who have passed legal authentication can communicate in the group. The ring signature is an effective solution. In addition, the group membership in the vehicular self-organising network changes rapidly, which leads to dynamic adjustment of group members. It is necessary to consider the computing power and communication capability of each node in the group members. To speed up the authentication process, a roadside unit with more computing power and communication capability than vehicles is selected as the signature agent, which effectively reduces the computational load of vehicles and accelerates the communication throughput. Meanwhile, the computational task and communication overhead have not been well-solved. To address these issues, this paper proposed an efficient proxy ring signature scheme for VANET to achieve higher signature efficiency and lower transmission overhead. The scheme allows both privacy protection and original signer tracing. Security analysis shows that the proposed scheme meets the security requirements of VANET. [ABSTRACT FROM AUTHOR]

In this paper, we investigate a multicast routing problem with quality of service constraints on ad hoc vehicular networks. An integer programming formulation for the problem is proposed that forms the basis of a relax‐and‐fix heuristic designed with the goal of producing feasible solutions of good quality. In addition, preprocessing procedures relying on simple and constrained shortest paths are developed that reduce the model size to the point of making it viable to compute. Computational experiments on benchmark instances generated to mimic realistic settings are reported. The results highlight the effectiveness of the relax‐and‐fix heuristic and the importance of the preprocessing routines for the computability of the proposed mathematical model. [ABSTRACT FROM AUTHOR]

This paper reports about our experience in designing and developing Chameleon, a highly portable and adaptable group communication framework for smartphones. Chameleon owes its level of portability to several design choices, including the following: (i) a layered architecture, where the headers of each layer have a standard XML-based format, enabling automatic, error-resistant generation of efficient serialization code in any platform; (ii) reliance only on the J2ME library, which serves as least common denominator for Java dialects and facilitates automatic translation to.NET; (iii) having flexible membership models; and (iv) supporting multiple concurrent protocol stacks.Through a single codebase, Chameleon is currently available as an open-source project for J2ME, J2SE, Android,.NET CF, and.NET. Chameleon is easily extendable and is bundled with tools, configurations, and third-party code tuned in a way that lifts some of the burden normally associated with multiplatform development for smartphones. Both the header generation from XML and automatic translation to.NET features of Chameleon are readily available to any application that is based on it. Chameleon's threading model separates between execution of internal layers and application's code and by that protects one from the other. As we describe in the paper, it simplifies layers' development and allows the protocol stack to easily block application calls when this is required by internal algorithms. Additionally, this model simplifies testing, and an extensive testing framework is supplied along with Chameleon, which is also usable for testing of application-specific layers. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A mobile ad hoc computational grid is a distributed computing infrastructure that allows mobile nodes to share computing resources in a mobile ad hoc environment. Compared to traditional distributed systems such as grids and clouds, resource allocation in mobile ad hoc computational grids is not straightforward because of node mobility, limited battery power and an infrastructure-less network environment. The existing schemes are either based on a decentralized architecture that results in poor allocation decisions or assume independent tasks. This paper presents a scheme that allocates interdependent tasks and aims to reduce task completion time and the amount of energy consumed in transmission of data. This scheme comprises two key algorithms: resource selection and resource allocation. The resource selection algorithm is designed to select nodes that remain connected for a longer period, whereas the resource assignment or allocation algorithm is developed to allocate interdependent tasks to the nodes that are accessible at the minimum transmission power. The scheme is based on a hybrid architecture that results in effective allocation decisions, reduces the communication cost associated with the exchange of control information, and distributes the processing burden among the nodes. The paper also investigates the relationship between the data transfer time and transmission energy consumption and presents a power-based routing protocol to reduce data transfer costs and transmission energy consumption. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

One of the significant challenges of the Radio over fibre (RoF) Medium Access Control (MAC) protocol is the propagation delay. This delay can lead to serious issues, such as higher propagation delay resulting in collisions and unnecessary retransmissions. Quantum entanglement is an excellent candidate to overcome the propagation delay of the RoF MAC protocol. A new quantum MAC protocol is proposed, named the Quantum Entanglement‐based MAC protocol (QE‐MAC), in which Quantum Teleportation is utilised to address the propagation delay. Four entanglement states are employed to represent the control packets of the classical MAC protocol, and data is transmitted over the classical channel. Instead of using control packets such as acknowledgement, request to send, and Clear to send, state transitions are employed. This approach avoids the delay and collision issues associated with control packets, resulting in a significant improvement in network performance. The delay, duty cycle (DC), and power consumption of the proposed QE‐MAC protocol are formulated and derived. The protocol is evaluated in terms of delay, DC, and power consumption, demonstrating superior performance compared to the classical RoF MAC protocol. In comparison to published works, our proposed approach has successfully reduced both delay and power consumption by 35%. [ABSTRACT FROM AUTHOR]

The escalating issue of forest fires poses severe risks to ecosystems and human habitats, primarily due to the greenhouse effect and sudden climate changes. These fires, mostly occurring naturally, necessitate prompt detection and control. Addressing this, the authors introduce the Forest Fire Detection, Prediction, and Behaviour Analysis (FDPA) system, an innovative Internet of Things (IoT) solution. The FDPA system leverages a wireless sensor network to efficiently detect and analyse fire behaviour, providing real‐time data on fire spread, speed, and direction. Uniquely, it can anticipate natural fires hours before they occur by monitoring ecological parameters such as humidity, temperature, and using the Chandler Burning Index (CBI) for quantifying fire danger. Designed for the challenging forest environment, the FDPA system prioritises minimal power usage and simple components, crucial in areas with limited power resources. Its resilient design ensures the wireless sensor network and sensor nodes withstand harsh weather and fire conditions, maintaining functionality and reliability. Field tests of the FDPA system in various Jordanian forest locations, including Burgish–Ajloun, have demonstrated its effectiveness. The trials revealed the system's capability in early fire detection, low latency response, predicting fire behaviour, and determining fire spread direction. Continuous monitoring of the forest ecosystem and rapid detection allow authorities to act swiftly, preventing potential fires from escalating. Furthermore, the system tracks ecological changes within the forest, offering insights into imminent natural fires. This feature enables proactive measures to mitigate fire spread, safeguarding the environment and nearby communities. The strategic placement of sensor nodes and the use of durable yet straightforward components reduce the risk of system damage due to environmental extremities. Overall, the FDPA system emerges as a promising tool for forest fire management. Its ability to detect, predict, and analyse forest fires in real‐time positions it as a vital asset in minimising the detrimental impacts of forest fires on the environment and human settlements. [ABSTRACT FROM AUTHOR]

Providing optimal resource utilization while minimizing costs involved for wireless networks remains a challenging issue. Particularly mobile ad hoc environments subject to multi-path fading and characterized by a dynamic topology need better resource management mechanisms. The focus of this paper is the performance evaluation of IEEE 802.11e MAC layer modeling under slow time-varying Rayleigh fading channel via both layered and multi-layered design approaches via a non-Markovian Stochastic Petri Nets modeling. We propose two MAC IEEE 802.11e models considering service differentiation features. The first one is non cross-layer based, whereas the second is cross-layer based. The cross-layer design approach adopted permits us to deal with both collisions and fading. We show the impact of the virtual load on the expected throughput. Compared to the conventional approach, our cross-layered design approach provides significant performance gains. Copyright © 2010 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, we derive throughput of a threshold-based transmission policy, namely load-regulated carrier sense multiple access (CSMA), taking into account the propagation delay of the medium and the offered load at different probabilities of the fading channel. In case of the saturated load-regulated CSMA, a trivial relationship between deterministic offered load to the channel at a particular fading channel condition and the maximum possible offered load has been shown. We further extend the load regulation concept into multi-channel domain. Both single and multi-channel load-regulated CSMA improves the throughput of the system compared with the existing CSMA system, which does not consider channel fading to control the packet transmissions. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The expansion of a communication area and the provision of services to wide districts can be expected if ad hoc networks are connected to established networks. In this environment, two types of routes exist between mobile stations that compose ad hoc networks: routes using wireless links only and routes via base station and the established networks. However, most routing protocols decide a route simply by the minimum hop counts between mobile stations without taking the differences of communication performance between the established network and ad hoc networks into account. This paper presents a new routing protocol that uses simple formulas to decide which route is effective, a route using wireless links only, or a route via the established networks. The formulas are derived from the results of simulation on the communication performance of some routes that uses IEEE802.11b as wireless links and Ethernet of 100 Mb/s as wired links. The performance of our proposed routing protocol, which is realized as an extension of ad hoc on-demand distance vector (AODV), is evaluated by simulation. The results show that the proposed routing protocol is effective especially under a high data rate situation compared with AODV. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(10): 47– 56, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20363 [ABSTRACT FROM AUTHOR]

In this paper we propose a new broadcasting algorithm. In the proposed method we significantly reduce the broadcast overhead and also improve the broadcast delivery ratio in mobile networks. A novel traffic isolation method has been used which reduces the control message exchange. The proposed broadcasting method is based on a clustering method called ‘stability-based clustering algorithm’ which had been proposed before. The broadcasting traffic is divided into internal (flow inside a cluster) and external traffic (flow among the clusters). For internal flooding traffic, cluster-heads and gateways are responsible for re-broadcasting but for external type, border nodes may perform the forwarding function as well. This simplifies the gateway selection method through the local selection of gateway nodes by its cluster head. Therefore, a cluster head selects gateway in its own cluster without any knowledge of other clusters. Considering the effect of mobility and node density, simulations have been conducted in a number of wireless environments. Simulation results show the broadcast coverage is close to 100% at different node speeds. Moreover, we study the broadcast parameters in light and dense networks and show improvement of the overhead and the number of forward nodes in comparison to other broadcasting methods. Copyright © 2005 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, we address the problem of broadcast routing in mobile ad hoc networks from the viewpoint of energy efficiency. In an ad hoc wireless network, each node runs on a local energy source which has a limited energy lifespan. Thus, energy conservation is a critical issue in ad hoc networks. One approach for energy conservation is to establish routes which require lowest total energy consumption. This optimization problem is referred as the minimum-energy broadcast routing problem (MEBRP). In this paper, we propose new efficient algorithms for the construction of energy-efficient trees for broadcast in mobile ad hoc networks. These algorithms exploit the broadcast nature of the wireless channel, and address the need for energy-efficient operations. Empirical studies show that our algorithms are able to achieve better performance than algorithms that have been developed for MEBRP. Copyright © 2004 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Clustering algorithm is the primary technology used in target clustering and group status analysis which are key features of the Unmanned Aerial Vehicles (UAVs) control system. Due to variable application environment, the stability of the algorithm in the UAVs control system needs to be considered. K‐means clustering is a widely used method in intelligent systems. However, K‐means algorithm is susceptible to the local optimum due to the influence of the initial centroid. For this problem, the predecessors have proposed various effective solutions. These algorithms perform better on real and large‐scale datasets, but they are unable to achieve optimum results with unbalanced datasets. Herein, a simpler and more effective algorithm for seed initialization is proposed, it has a better accuracy rate than the alternative algorithms.Moreover, after running tests multiple times with each algorithm independently, it has the highest stability and the lowest overall volatility. With unbalanced datasets, the proposed algorithm performs significantly better than several other algorithms and therefore can solve the problems that other algorithms have with unbalanced datasets. [ABSTRACT FROM AUTHOR]

IP header compression schemes offer a valuable measure for bandwidth preservation. Such schemes have been practically implemented in infrastructure-based IP networks for point-to-point links. However, minimal research and practical implementation efforts have been conducted in the direction of an IP header compression strategy that can meet the peculiar requirements of multihop ad hoc wireless networks. In this paper, we present a practically implemented multi-hop IP header compression scheme using the Robust Header Compression (ROHC) protocol suite. The scheme runs on a novel identifier (ID) based networking architecture, known as an ID-based ad hoc network (IDHOCNET). IDHOCNET additionally solves a number of bottlenecks of pure IP-based ad hoc networks that have emerged owing to IP address autoconfiguration service, distributed naming and name resolution, and the role of an IP address as an identifier at the application layer. The proposed scheme was tested on a multi-hop test bed. The results show that the implemented scheme has better gain and requires only O (1) ROHC contexts. [ABSTRACT FROM AUTHOR]

SUMMARY In ad hoc networks, directional antennas offer many benefits compared with classical omnidirectional antennas. Those include significant increases in spatial reuse, coverage range, and subsequently network capacity as a whole. Most of the proposed directional medium access control methods assume that all the nodes in the network have homogeneous antenna types. However, it is quite unusual that a sudden change will occur, and every laptop, palmtop, computer, and other similar device will be turned into a directional antenna holding device. There will always be a possibility of heterogeneous antenna used in the deployed nodes of the network. In this paper, we have proposed a medium access control protocol that deals with the new challenges introduced into heterogeneous networks in the form of deaf and hidden node problems. Using Optimized Network Engineering Tools 16.0, we have simulated three ad hoc network scenarios. These scenarios have different ratios of omnidirectional and directional nodes. We evaluated the performance of these scenarios by varying the ratio. We found that when we increase the directional nodes in the network, the performance increases. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Poisson multi‐Bernoulli Mixture (PMBM) filter has been known as an available or practical point and multiple extended target tracking (METT) method. The authors present an improved PMBM filter with adaptive detection probability and adaptive newborn distributions, accompanying with an associated distributed fusion strategy for the tracking extended multiple targets. First, the augmented state of unknown and changing target detection probability is assumed as Gamma (GAM) distribution. Second, extended states are described by Inverse Wishart (IW) distribution based on this augmented state, accompanying with dynamic states presented by Gaussian distribution. And then, an adaptive newborn distribution is adopted to describe the newborn targets appearing arbitrarily. Consequently, the closed‐form solutions of the proposed filter can be derived by approximating the intensity of newborn and potential targets to the Gamma Gaussian Inverse Wishart (GGIW) form. Moreover, the fused means that Generalised Covariance Intersection (GCI) is performed in such a large‐scale aquaculture sensor network. Experiments are presented to verify the availability of the GCI‐GGIW‐PMBM method, and comparisons with other METT filters also demonstrate that tracking behaviours are improved largely. [ABSTRACT FROM AUTHOR]

Green communication has recorded much attention in industry, academia and government. It has been recorded that information communication and technology nodes consume roughly 3% of the world‐wide energy supply and are responsible for 2% of the global carbon dioxide (CO2) emission. As a result, researchers have devoted huge attention to prevent its growth. In order to address this problem we studied coded packet approach, which is the current method of minimising energy in wireless multicast networks. Then, we propose novel approaches that are based on data envelopment analysis (DEA) to further optimise energy consumption in wireless multicast networks. We found that existing approaches to energy efficient multicast are unsuitable for evaluating efficiency adequately. This paper takes the position that true efficiency evaluation is obtained when both inputs and outputs with multiple variables are considered in measuring performance using ratios of weighted outputs to weighted inputs. As a result, we developed the input‐oriented variable return to scale (VRS) envelopment with slacks models for energy efficiency in ad hoc wireless multicast networks. We explored the random linear network coding (RLNC) based on simulation approach and compared the results with the input‐oriented VRS DEA envelopment with slacks approach. The results show the DEA approach substantially saves energy compared to the RLNC. Furthermore, we show that DEA method has the capability to identify which ad hoc network is inefficient and projected them onto the efficient frontier. [ABSTRACT FROM AUTHOR]

SUMMARY Random waypoint (RWP) mobility model is widely used in ad hoc network simulation. The model suffers from speed decay as the simulation progresses and may not reach the steady state in terms of instantaneous average node speed. Furthermore, the convergence of the average speed to its steady state value is delayed. This usually leads to inaccurate results in protocol validation of mobile ad hoc networks modeling. Moreover, the probability distributions of speed vary over the simulation time, such that the node speed distribution at the initial state is different from the corresponding distribution at the end of the simulation. In order to overcome these problems, this paper proposes a modified RWP mobility model with a more precise distribution of the nodes' speed. In the modified model, the speeds of nodes are sampled from gamma distribution. The results obtained from both analysis and simulation experiments of the average speed and the density of nodes' speed indicate that the proposed gamma random waypoint mobility model outperforms the existing RWP mobility models. It is shown that a significant performance improvement in achieving higher steady state speed values that closely model the pre-assumed average speeds are possible with the proposed model. Additionally, the model allows faster convergence to the steady state, and probability distribution of speed is steady over the simulation time. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, an analytical model is proposed to calculate the network throughput of dedicated control channel protocols that are designed to schedule multiple packets to be transmitted on different data channels simultaneously. Based on the analytical model, a scheme by tuning the initial contention window size is proposed to maximize the network throughput. We also present a novel multi-channel MAC protocol for single-hop scenario. Simulation results show that the proposed model is capable of modeling the behaviors of dedicated control channel protocols accurately. Furthermore, the proposed scheme can reduce the cost of collisions and enhance the network throughput up to 22% for 1 kB packet size and 80 nodes. Compared with other dedicated control channel protocols, the proposed protocol can schedule more control packets and use multiple channels more efficiently. Copyright © 2010 John Wiley & Sons, Ltd. An analytical model is proposed to calculate the network throughput of dedicated control channel protocols that are designed to schedule multiple packets to be transmitted on different data channels simultaneously. Based on the analytical model, a scheme by tuning the initial contention window size is proposed to maximize the network throughput. We also present a novel multi-channel MAC protocol for a single-hop scenario. Copyright © 2010 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Mobile Ad hoc NETwork (MANET) presents a constrained communication environment due to fundamental limitations of client resources, insufficient wireless bandwidth and users' frequent mobility. Caching of frequently accessed data in such environment is a potential technique that can improve the data access performance and availability. Co-operative caching, which allows the sharing and co-ordination of cached data among clients, can further explore the potential of the caching techniques. In this paper, we propose a novel scheme, called zone co-operative (ZC) for caching in MANETs. In ZC scheme, one-hop neighbours of a mobile client form a co-operative cache zone. For a data miss in the local cache, each client first searches the data in its zone before forwarding the request to the next client that lies along routing path towards server. As a part of cache management, cache admission control and value-based replacement policy are developed to improve the data accessibility and reduce the local cache miss ratio. An analytical study of ZC based on data popularity, node density and transmission range is also performed. Simulation experiments show that the ZC caching mechanism achieves significant improvements in cache hit ratio and average query latency in comparison with other caching strategies. Copyright © 2006 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper investigates the issues of QoS routing in CDMA/TDMA ad hoc networks. Since the available bandwidth is very limited in ad hoc networks, a QoS request between two nodes will be blocked if there does not exist a path that can meet the QoS requirements, even though there is enough free bandwidth in the whole system. In this paper, we propose a new scheme of using multiple paths between two nodes as the route for a QoS call. The aggregate bandwidth of the multiple paths can meet the bandwidth requirement of the call and the delays of these paths are within the required bound of the call. We also propose three strategies by which to choose a set of paths as the route, namely, shortest path first (SPF), largest bandwidth first (LBF), and largest hop-bandwidth first (LHBF). Extensive simulations have been conducted to evaluate the performance of the three strategies in comparison with a traditional single path routing algorithm. The simulation results show that the proposed multiple paths routing scheme significantly reduces the system blocking rates in various network environments, especially when the network load is heavy. Copyright © 2005 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In recent years, constructing a virtual backbone by nodes in a connected dominating set (CDS) has been proposed to improve the performance of ad hoc wireless networks. In general, a dominating set satisfies that every vertex in the graph is either in the set or adjacent to a vertex in the set. A CDS is a dominating set that also induces a connected sub-graph. However, finding the minimum connected dominating set (MCDS) is a well-known NP-hard problem in graph theory. Approximation algorithms for MCDS have been proposed in the literature. Most of these algorithms suffer from a poor approximation ratio, and from high time complexity and message complexity. In this paper, we present a new distributed approximation algorithm that constructs a MCDS for wireless ad hoc networks based on a maximal independent set (MIS). Our algorithm, which is fully localized, has a constant approximation ratio, and O(n) time and O(n) message complexity. In this algorithm, each node only requires the knowledge of its one-hop neighbours and there is only one shortest path connecting two dominators that are at most three hops away. We not only give theoretical performance analysis for our algorithm, but also conduct extensive simulation to compare our algorithm with other algorithms in the literature. Simulation results and theoretical analysis show that our algorithm has better efficiency and performance than others. Copyright © 2005 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In recent years, a variety of new routing protocols for mobile ad hoc wireless NETworks (MANETs) have been developed. Performance evaluation and comparison of many of these routing protocols have been performed using detailed simulation models. Zone routing protocol (ZRP) is one of these routing protocols, which is a hybrid routing protocol that proactively maintains routing information for a local neighbourhood (routing zone), while reactively acquiring routes to destinations beyond the routing zone. The studies on ZRP have assumed homogeneous scenarios where all mobile nodes have uniform mobility and are statistically identical, lacking the studies on heterogeneous scenarios where mobile nodes move with non-uniform mobilities in the same network. In this paper, we study the performance of ZRP in such scenarios. We propose an efficient scheme for ZRP to adapt to the non-uniform mobilities scenario and study its performance for different mobility scenarios, network loads and network sizes. Copyright © 2003 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The rigid body localization (RBL) technique is capable of estimating the state of a rigid body, including its translation and orientation, by utilizing the interactions between sensors and landmarks. The prevalent RBL methods employ precise time‐of‐flight measurements (or range measurements) to estimate the state. However, the clock offsets in range measurements in asynchronous networks are unavoidable, leading to performance degradation for state estimators. Therefore, range difference measurements have been adopted to solve the RBL problem. However, existing approaches struggle to achieve desirable performance while maintaining computational efficiency. To address this issue, a new closed‐form state estimator for asynchronous networks is introduced. The proposed algorithm leverages the Taylor‐series expansion technique to enhance accuracy while keeping computational overhead low. Numerical experiments demonstrate that the proposed method achieves state‐of‐the‐art performance with high computational efficiency under small Gaussian noises. [ABSTRACT FROM AUTHOR]

Given the observed developments of novel communication modes and the establishment of next‐generation cellular networks, mobility modelling and ad hoc routing requirements have emerged. Flying ad hoc networks are key pivots in enabling technological leaps in the domain of on‐demand communications, especially in emergency scenarios; as such, resorting to application‐ and mobility‐aware routing is a promising enabler of this emerging set of use cases. This article investigates swarm mobility modelling, and applicable routing protocols, conducting comparative analysis that leads to the introduction of the new Anchored Self‐Similar 3D Gauss‐Markov Mobility Model (ASSGM‐3D), which incorporates a novel set of spatio‐temporal statistical metrics. [ABSTRACT FROM AUTHOR]

The idea of aggregate signcryption was first proposed by Selvi. The aggregation process reduces the communication overhead and hence, it is efficient in low‐bandwidth communication networks such as wireless sensor networks and vehicular ad‐hoc network VANET. The goal of this study is to propose a secure provably identity based aggregate signcryption scheme ID‐ASC without pairings over the elliptic curve cryptography. The proposed scheme is provable secure against confidentiality and unforgeability under random oracle model. Moreover, the proposed ID‐ASC reduced the computational complexity when compared to other schemes in literature. [ABSTRACT FROM AUTHOR]

A wireless ad hoc network consisting of one‐hoping relay channel and some interfering nodes with possible arbitrary correlation between wireless channels coefficients is studied. By exploiting a novel approach called Copula theory, enabling us to describe joint probability distribution function for arbitrarily correlated random variables, the authors derive a closed‐form expression for success probability in different dependence structures of channels. Specifically, by applying the Farlie–Gumbel–Morgenstern (FGM) Copula and the popular Archimedean (Clayton, Gumbel, and Frank) Copulas, they analyse the network performance in terms of success probability, and show that the channels correlation improves the performance of success probability so that whenever the dependence structure tends to higher values, the performance improvement is increased. Besides, it is found that the investigation of channel correlation effects by FGM Copula is more tangible compared to Archimedean Copulas. Finally, the efficiency of the analytical results is illustrated numerically. [ABSTRACT FROM AUTHOR]

Cooperative spectrum sensing (CSS) among secondary users (SUs) in cognitive radio ad hoc networks exhibits an essential trade‐off minimising the misdetection probability of the primary user and maintaining a reasonable false alarm probability to obtain efficient spectrum utilisation. In this study, distributed coalition formation game with a genetic algorithm is proposed to select the optimal coalitional head. It provides an incentive to SUs that improve their detection performance and cooperation among SUs. Since spectrum sensing will incur a cost for SUs, an incentive mechanism is necessary to motivate active participation. Consider the CSS problem as a non‐transferable coalition game and it is used to allow the SUs to self‐organise into disjoint coalitions while accounting for the CSS. The authors calculate payoff for each SU to form minimum winning coalition and to analyse their strategy profile for joining in coalition based on its utility maximisation. Simulation results reveal that the proposed algorithm has significantly improved sensing accuracy, minimised energy consumption and thereby enhanced CSS. [ABSTRACT FROM AUTHOR]

Owing to the limited network resources in ad hoc networks, improving network throughput is the key to solve network congestion and increase network transmission efficiency. Back‐pressure routeing, as an optimal routeing strategy for throughput, has recently received substantial attention for joint routeing and scheduling over multi‐hop wireless networks. However, the inefficient routeing decision and complex queueing management of back‐pressure routeing make it unsuitable for practical applications. This study proposes an improved back‐pressure routeing algorithm with one first‐input–first‐output (FIFO) queueing structure using the shortest‐path decision. By making use of the shortest‐path knowledge, the feasible routes quickly converge to the shortest path when the network is lightly loaded. On the other hand, when the network load is heavy, the proposed algorithm remains optimal for exploring all the feasible paths between each source and destination. The back‐pressure routeing design based on a single‐FIFO queue architecture greatly simplifies the complexity of packet queueing management. The authors' results indicate that the proposed routeing algorithm achieves lower end‐to‐end delay than that of some other back‐pressure algorithms without reducing the network throughput performance. [ABSTRACT FROM AUTHOR]

In this study, the authors address the problem of combining hierarchical and flat techniques to construct and maintain nodes' connectivity as well as links' symmetry (bidirectionality) in a wireless sensor network (WSN) comprising static nodes. They propose a localised and asynchronous self‐stabilising hybrid message passing a solution that seamlessly merges three well known connectivity control techniques for such ad hoc networks, namely k ‐hop clustering (k≥1), power control (transmission range adjustment) and sleep/wake scheduling. Their stigmergy‐based strategy (i.e. inspired from ants' pheromone‐based communication, division of labour and swarming behaviours) allows a WSN to simultaneously cope with issues such as scalability, fault tolerance, transmission range minimisation, energy hole problem (i.e. premature node deaths in the vicinity of the sink), channel overhearing and signalisation reduction. To the best of their knowledge, such a solution does not exist in the literature. The few self‐stabilising hybrid connectivity control protocols currently proposed use only two of the above‐mentioned techniques. The authors formally prove the correctness of their scheme and its self‐stabilisation property under an unfair distributed daemon. Simulation results show that the proposed scheme has a low average convergence time, is energy efficient and can prolong network lifetime. [ABSTRACT FROM AUTHOR]

Location aware sensor routing (LASeR) protocol is a novel solution to the challenges of routing in mobile wireless sensor networks (MWSNs). It addresses the high reliability and low latency requirements of emerging applications. The protocol uses location information to maintain a gradient field even in highly mobile environments, whilst reducing the routing overhead. This allows the protocol to utilise a blind forwarding technique to propagate packets towards the sink. The protocol inherently utilises multiple paths simultaneously to create route diversity and increase its robustness. LASeR is designed for use in a high variety of MWSN applications with autonomous land, sea or air vehicles. Analytical expressions are derived and evaluated against the simulations. Extensive modelling and simulation of the proposed routing protocol has shown it to be highly adaptable and robust. It is compared with the recent MWSN proactive highly ambulatory sensor routing protocol, the high performance mobility adaptive cross‐layer routing protocol, as well as ad‐hoc on‐demand distance vector and optimised link state routing. Protocols are evaluated on packet delivery ratio, end‐to‐end delay, overhead, throughput and energy consumption. The results highlight both the high performance of LASeR in various challenging environments and its superiority over the state‐of‐the‐art. [ABSTRACT FROM AUTHOR]

This study introduces a geographical multi‐layered clustering protocol for ad hoc wireless sensor networks (WSNs), where the size of clusters is variable so that the closer clusters to the base station (BS) have a smaller size than farther ones. Moreover, in each cluster, using some intelligent fuzzy rules and in a decentralised way, a novel sub‐tree strategy is determined. In this way, some parent nodes are chosen that are responsible for collecting and aggregating data from their adjacent ordinary nodes and sending them to its cluster head, directly or via other parent nodes, which substantially decreases intra‐cluster communication energy costs. Furthermore, these two compatible techniques can fairly mitigate the hot spot problem resulting from multi‐hop communication with the BS. The simulation results demonstrate that the proposed protocol outperforms two energy‐efficient protocols named DSBCA and LEACH in terms of functional network longevity for both small‐scale and large‐scale sensor networks. [ABSTRACT FROM AUTHOR]

In this study, the impact of route length on the performance of a routing protocol and flow admission control is analysed. First, the authors present an end‐to‐end available‐bandwidth‐based proactive routing protocol for ad‐hoc wireless sensor networks. The routing protocol maintains the best data forwarding path in terms of the end‐to‐end available bandwidth. Second, to determine the impact of route length on a routing protocol's performance, they modify the routing protocol. The modified available‐bandwidth‐based protocol trades‐off the end‐to‐end available bandwidth against the route length. Third, they integrate a state‐of‐the‐art flow admission control algorithm with the proposed protocols and a shortest hop‐count‐based protocol. Through simulations they evaluate the following: (i) performance of the proposed protocols and a state‐of‐the‐art available‐bandwidth‐based opportunistic protocol and (ii) the effectiveness of a state‐of‐the‐art flow admission control algorithm over proposed protocols and a shortest hop‐count‐based protocol. The simulation results demonstrate the following drawbacks of not considering the hop‐count metric: longer data forwarding paths, higher number of retransmissions, and reduced effectiveness of the admission control algorithm. The modified available‐bandwidth‐based proactive protocol provides the best overall performance. Therefore, using their results they conclude that route length impacts the performance of routing and flow admission control algorithms, but is not a singularly decisive factor. [ABSTRACT FROM AUTHOR]

According to the disadvantages of real time and continuity for multimedia services in ad hoc networks, a delay constraint multipath routing protocol for wireless multimedia ad hoc networks, which can satisfy quality of service (QoS) requirement (QoS multipath optimized link state routing [MOLSR]), is proposed. The protocol firstly detects and analyzes the link delay among the nodes and collects the delay information as the routing metric by HELLO message and topology control message. Then, through using the improved multipath Dijkstra algorithm for path selection, the protocol can gain the minimum delay path from the source node to the other nodes. Finally, when the route is launched, several node-disjoint or link-disjoint multipaths will be built through the route computation. The simulation and test results show that QoS-MOLSR is suitable for large and dense networks with heavy traffic. It can improve the real time and reliability for multimedia transmission in wireless multimedia ad hoc networks. The average end-to-end delay of QoS-MOLSR is four times less than the optimized link state routing. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

To form cognitive radio nodes into a wireless ad‐hoc network, generally, globally or locally common channels are assumed to be available or some channels are dynamically selected as locally common ones. However, a cognitive radio node is not licensed to any channel for communication. With dynamic channel availability, neither locally nor globally common channels could be assumed available. Therefore, in this study, a new approach for cognitive radio network formation is presented that is not constrained by the availability of common channels. The proposed approach is based on the 'group' concept. Activated cognitive radio nodes form multiple 'groups' according to some criteria. Each group consists of a head node, some gateway nodes and ordinary nodes. During sensing phase, nodes sense channels and negotiate the channel and time slot assignment; thus, during data transmitting phase, each node is able to communicate with its different neighbour nodes in assigned channels during given time slots. Hence, nodes can be connected together to form a network without common channels and the network connectivity is improved. This study presents the network forming process including neighbour node detection, node communication, group formation, time slot assignment, channel assignment and medium access control protocol. Finally, simulations are conducted to investigate the network connectivity. [ABSTRACT FROM AUTHOR]

Outage probability performance of multiple‐input multiple‐output (MIMO) ad‐hoc network with quantised beamforming and finite rate feedback is analysed with the assumption that the nodes are uniformly distributed with random topology. In quantised beamforming, each receiver sends the label of the best beamforming vector obtained from the codebook to the transmitter through a finite rate limited feedback. The code book is shared between the desired users to prevent decoding of other user's information in a MIMO ad‐hoc network. In such a practical environment, feedback links can only convey finite number of bits, from which transmit beamformer designs are investigated using either the outage probability or average signal to interference ratio as the figure of merit. In this study, a mathematical analysis for the estimation of the interference power statistics and the corresponding outage probability in MIMO wireless ad‐hoc networks with random position of interference nodes is carried out. In lieu of validating the obtained simulation results, theoretical results have also been compared. [ABSTRACT FROM AUTHOR]

In an ad hoc network, selfish nodes do not cooperate in packet forwarding of other nodes to maximise their own welfare. Such nodes will have a negative effect on the performance of the network. In this study, an enhanced node cooperation technique (ENCT) is proposed which is a hybrid technique of reputation‐based mechanism and incentive‐based mechanism. It evaluates relaying nodes' behaviour, calculates its reputation and outwitting selfish nodes by utilising receipts submitted by each relaying node in the path to a centralised authority rather than using promiscuous mode. A mathematical analysis is provided which demonstrates that the expected gain of reputation for a particular node is maximum if it adopts cooperative behaviour. To motivate nodes for cooperation, variable incentives are provided proportionate to their reputation and current behaviour. Simulation results demonstrate modification of reputation and incentive with varying number of selfish nodes, traffic connections, and topology with static and dynamic behaviour of selfish nodes. The result shows that the ENCT is robust, fair and efficient technique. [ABSTRACT FROM AUTHOR]

In this study, the authors propose a cluster‐based trust management model that efficiently detects the malicious nodes and restricts them to be on a route in wireless ad hoc networks. In contrast to previous works, the trust of a node is calculated using various trust attributes having substantial effect on reliable routing in the networks. In the proposed model, each node periodically predicts the value of each trust attribute about other nodes using autoregression. Subsequently, the direct trust is estimated using the weighted combination of trust attributes and it is fine tuned using proportional–integral model. All these recommendation trusts, from common neighbours, are collected and combined by the clusterhead to quantify the trust, and hence the routing is reliable and secure in the proposed model. Simulation results show that the proposed trust model provides better throughput and packet delivery ratio in presence of malicious nodes compared to other existing schemes. [ABSTRACT FROM AUTHOR]

In this study the authors consider the energy consumption of mobile agents operating in wireless local area network (WLAN) environment. They present an energy model of an ad hoc WLAN based on the IEEE 802.11 standard and analyse both per‐device and WLAN‐wide energy consumption. With this model the authors investigate 'features' of the 802.11 protocol (such as frame fragmentation, preamble/header lengths and power‐save schemes) on energy consumption in the context of a mobile agent management domain. They also consider 'clustering' as a means of optimising energy consumption. [ABSTRACT FROM AUTHOR]

In ad hoc wireless networks, most data are delivered by multi-hop routing (hop by hop). This approach may cause long delay and a high routing overhead regardless of which routing protocol is used. To mitigate this inherent characteristic, this work presents a novel ad hoc network structure that adopts dual-card-mode, self-organization with specific IP naming and channel assignment to form a hierarchical star graph ad hoc network (HSG-ad hoc). This network not only expedites data transmission but also eliminates the route discovery procedure during data transmission. Therefore, the overall network reliability and stability are significantly improved. Simulation results show that the proposed approach achieves substantial improvements over DSDV, AODV, and DSR in terms of average end-to-end delay, throughput, and packet delivery ratio. Copyright © 2009 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We study the connectivity properties of a family of random graphs that closely model the Bluetooth's device discovery process, where each device tries to connect to other devices within its visibility range in order to establish reliable communication channels yielding a connected topology. Specifically, we provide both analytical and experimental evidence that when the visibility range of each node (i.e. device) is limited to a vanishing function of n, the total number of nodes in the system, full connectivity can still be achieved with high probability by letting each node connect only to a ‘small’ number of visible neighbors. Our results extend previous studies, where connectivity properties were analyzed only for the case of a constant visibility range, and provide evidence that Bluetooth can indeed be used for establishing large ad hoc networks. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

An ad hoc network is a collection of nodes that do not need to rely on a predefined infrastructure to keep the network connected. Nodes communicate amongst each other using wireless radios and operate by following a peer-to-peer network model. In this article, we propose a multifold node authentication approach for protecting mobile ad hoc networks. The security requirements for protecting data link and network layers are identified and the design criteria for creating secure ad hoc networks using multiple authentication protocols are analysed. Such protocols, which are based on zero-knowledge and challenge-response techniques, are presented through proofs and simulation results. Copyright © 2007 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We consider ad hoc wireless networks and the topology control problem defined as minimizing the amount of power needed to maintain connectivity. The issue boils down to selecting the optimum transmission power level at each node based on the position information of reachable nodes. Local decisions regarding the transmission power level induce a subgraph of the maximum powered graph Gmax in which edges represent direct reachability at maximum power. We propose a new algorithm for constructing minimum-energy path-preserving subgraphs of Gmax, i.e. ones minimizing the energy consumption between node pairs. Our algorithm involves a modification to the medium access control (MAC) layer. Its superiority over previous solutions, up to 60% improvement in sparse networks, demonstrates once again that strict protocol layering in wireless networks tends to be detrimental to performance. Copyright © 2005 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]