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Wireless mesh networks (WMNs) can act as a scalable backbone by connecting separate sensor networks and even by connecting WMNs to a wired network. The Hybrid Wireless Mesh Protocol (HWMP) is the default routing protocol for the 802.11s WMN. The routing protocol is one of the most important parts of the network, and it requires protection, especially in the wireless environment. The existing security protocols, such as the Broadcast Integrity Protocol (BIP), Counter with cipher block chaining message authentication code protocol (CCMP), Secure Hybrid Wireless Mesh Protocol (SHWMP), Identity Based Cryptography HWMP (IBC-HWMP), Elliptic Curve Digital Signature Algorithm HWMP (ECDSA-HWMP), and Watchdog-HWMP aim to protect the HWMP frames. In this paper, we have analyzed the vulnerabilities of the HWMP and developed security requirements to protect these identified vulnerabilities. We applied the security requirements to analyze the existing secure schemes for HWMP. The results of our analysis indicate that none of these protocols is able to satisfy all of the security requirements. We also present a quantitative complexity comparison among the protocols and an example of a security scheme for HWMP to demonstrate how the result of our research can be utilized. Our research results thus provide a tool for designing secure schemes for the HWMP. [ABSTRACT FROM AUTHOR]

This paper considers point-to-point secure communication over flat fading channels under an outage constraint. More specifically, we extend the definition of outage capacity to account for the secrecy constraint and obtain sharp characterizations of the corresponding fundamental limits under two different assumptions on the transmitter channel state information (CSI). First, we find the outage secrecy capacity assuming that the transmitter has perfect knowledge of the legitimate and eavesdropper channel gains. In this scenario, the capacity achieving scheme relies on opportunistically exchanging private keys between the legitimate nodes. These keys are stored in a key buffer and later used to secure delay sensitive data using the Vernam's one time pad technique. We then extend our results to the more practical scenario where the transmitter is assumed to know only the legitimate channel gain. Here, our achievability arguments rely on privacy amplification techniques to generate secret key bits. In the two cases, we also characterize the optimal power control policies which, interestingly, turn out to be a judicious combination of channel inversion and the optimal ergodic strategy. Finally, we analyze the effect of key buffer overflow on the overall outage probability. [ABSTRACT FROM AUTHOR]

Bluetooth Low Energy (BLE) is a recently developed energy-efficient short-range wireless communication protocol. In this paper, we discuss and compare the maximum peer-to-peer throughput, the minimum frame turnaround time, and the energy consumption for three protocols, namely BLE, IEEE 802.15.4 and SimpliciTI. The specifics and the main contributions are the results both of the theoretical analysis and of the empirical measurements, which were executed using the commercially available hardware transceivers and software stacks. The presented results reveal the protocols' capabilities and enable one to estimate the feasibility of using these technologies for particular applications. Based on the presented results, we draw conclusions regarding the feasibility and the most suitable application scenarios of the BLE technology. [ABSTRACT FROM AUTHOR]

Mobile ad hoc networks (MANETs) are very promising wireless technology and they support wide range of applications. Due to the dynamic nature of MANETS, their routing process faces several challenges. In this paper, we propose a new, Load and Stability Aware Ad Hoc on-demand Distance Vector protocol (LSA-AODV) for efficient data transmission in MANET. It applies fuzzy logic to stability metric and traffic density of the route. The ultimate intend is to select a reliable path for data communication and to reduce the number of route breakages, collisions and contention. It also utilizes stability and traffic density metrics to control broadcasting of routing messages. This protocol is compared with other similar routing protocols: LBAR and AODV. We use ns-2 for simulation. Our simulation results show that, the proposed protocol outperforms the existing routing protocols in terms of end-to-end delay and packet delivery ratio. It also considerably reduced the routing overhead. [ABSTRACT FROM AUTHOR]

Evaluating the performance of WCDMA wireless networks is important because it allows determining the types of applications that can be supported on such networks. BER of an average multi-hop route directly affects the ability of wireless network to support applications requiring a specific BER, for a given node transmission power and node spatial density. Given this feature, destination node can estimate stability of routes and can select the best and more stable route. Therefore we can reduce the delay and jitter of sending data packets. In this work, an attempt has been made to compare the performance of two prominent on demand reactive routing protocols and one proactive routing protocol for WCDMA scheme & these protocols are DSR, DSDV & AODV protocols. DSR and AODV is a reactive gateway discovery algorithm whereas DSDV comes under proactive category. A WCDMA scheme connects by gateway only when it is needed. our simulation results for all the three protocols based on metrics such as packet delivery rate, throughput, routing overhead and average end to end delay by using NS-2 simulator. [ABSTRACT FROM AUTHOR]

WirelessHART is considered to be one of the most promising wireless network protocols for its high robustness comparing to other similar wireless networks. The high robustness comes from its unique routing protocol and redundant superframe scheduling scheme. This paper focuses on the time-slot scheduling and channel assignment of WirelessHART and a graph route-based superframe scheduling scheme is proposed. In order to improve the communication reliability, our scheme applies hop-level retransmission mechanism in a multi-hop and multi-channel circumstance. Moreover, time-slot conflict and channel interference are considered and an effective solution strategy is proposed. To meet the real-time communication requirements, time-slots are assigned in the order of actual communication sequence which can effectively reduce the retransmission delay. Further more, we propose the implementation algorithm of our scheme. The performance analysis shows that our scheduling scheme has a higher robustness than the traditional non-redundancy scheme. [ABSTRACT FROM AUTHOR]

This paper presents the design, implementation and evaluation of the FreeMobility localization system-a distributed system that allows access points (APs) or cellular towers to dynamically determine the location of a mobile user using only received signal strength (SS) and mobility information (direction and traveled distance) from the mobile. FreeMobility does not require special infrastructure or installation, and it is readily applicable to commodity devices like laptops, PDAs and cell phones using existing Wi-Fi and/or cellular networks. This paper introduces mathematical methodology that dynamically predicts the location of the mobile; the paper also presents detailed analysis and experimental results that explore practical issues in implementing the system. FreeMobility was evaluated using: (1) measurements from IEEE 802.11 networks at both the University of South Carolina, Beaufort (USC Beaufort) and a residential neighborhood in Columbia, SC; and (2) online data resources from war-driving community and other research communities. The results demonstrate that FreeMobility provides reliable location estimates, and the localization error is comparable with other existing systems. With the assistance of the geographic information system (GIS), FreeMobility does not require dense tower deployment, and it is able to provide location attributes in addition to pure coordinates from most other systems. Copyright © 2009 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

SUMMARY When one considers the broad range of wirelessly connected mobile devices used today, it is clear that integrating such network-enabled devices into secure roaming over wireless networks is of essential importance. Over the years, many authentication protocols have been suggested to address this issue. Among these protocols, the recently proposed privacy-preserving universal authentication protocol, Priauth, exceeds the security and efficiency of other authentication techniques. This paper studies the existing roaming authentication protocols and shows that they are not strong enough to provide secure roaming services in three aspects. Further, using Priauth as an example, we propose efficient remedies that fix the weaknesses. The experimental results show that the proposed approaches are feasible in practice. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Wireless sensor networks (WSNs) have recently extended application areas to numerous sectors such as industrial automation, military applications, transportation systems, building management, and environment surveillance. In particular, WSNs provide flexible, reliable, cost-effective solutions to monitor the real-time status of automated manufacturing facilities. A facility-specific WSN for reliable monitoring and efficient management of industrial facilities is called the facility sensor network (FSN). In general, industrial facilities run various electromagnetic devices causing electromagnetic interference (EMI), which disturbs wireless data communication. To obtain accurate and reliable data in such environments, the FSN needs to deal with the EMI by proper deployment of sensor nodes and their validation and fusion. This paper proposes a data processing protocol, called Interfered Sensor Data Processing Protocol (ISDPP) to handle the EMI affecting wireless communication. ISDPP is developed with a data fusion algorithm and an exponentially weighted moving average/fuzzy logic-based error detection method to obtain reliable information from the FSN. To evaluate the performance, experiments in various settings are performed in a test-bed manufacturing facility. The experimental results indicate the interfered data, and outliers can be filtered out even if unexpected interferences occur in the facility. The FSN with the ISDPP can provide efficient real-time monitoring solutions for various industrial applications. [ABSTRACT FROM AUTHOR]

Abstract: Wireless mesh networking is an economic and convenient way to provide last mile Internet access through ad hoc peer-to-peer communication links. However, without systematic network configuration and channel resource management, these networks suffer from scalability, performance degradation and service disruption issues due to overwhelming co-channel interference, unscrupulous channel utilization and inherent network mobility. The IEEE 802.11 DCF and EDCA mechanisms based on CSMA/CA are the most widely used random channel access mechanisms, but unfortunately these cannot effectively eliminate hidden terminal and exposed terminal problems in multi-hop scenarios. Social network analysis techniques proposed for economic and social studies have recently been shown to be a successful approach for characterizing information propagation in multi-hop wireless networks. We propose a set of efficient resource allocation algorithms and channel access scheduling protocols based on Latin squares and social centrality metrics for wireless mesh networks (WMNs) with multi-radio multi-channel (MRMC) communication capabilities, called , which can coexist with IEEE 802.11 DCF and be effectively applied in large scale WMNs. Based on interference information provided by the interference graph, uses nodal degree centrality to form cliques for intra-cluster communication, and betweenness centrality to choose bridge nodes to form cliques for inter-cluster communication in WMNs, and then applies Latin squares to map the clique-based clustering structure to radios and channels for wireless communication purposes. Afterwards, again applies Latin squares to schedule the channel access amongst nodes within each cluster in a collision-free manner. We evaluate using simulations, and results show that achieves much better performance than existing IEEE 802.11 standards and other multi-channel access control protocols. [Copyright &y& Elsevier]

Wireless sensor networks have found their way to countless applications in many different fields. Due to the restricted power availability these systems are faced with, custom wireless protocols have been designed. Many different protocols have already been conceived, yet each application will impose different requirements. In inertial motion tracking, sensor nodes are applied on the body allowing full body posture reconstruction. These nodes must not hinder or restrict the movements of the user in any way, meaning that a wireless approach is desirable. A suiting protocol that insures robust simultaneous functionality of at least 15 nodes at a rate of 100Hz is required. A TDMA based protocol with master/slave hierarchy is presented for the application at hand. Nodes dynamically decide on their role within the network at startup and reassess the network state regularly. Conflicting situations are handled whenever they arise and nodes react accordingly creating a fully plug-and-play system. Careful implementation of the protocol in embedded software allows data transmission of 19 nodes while each of them consumes an average current of only 3mA. [ABSTRACT FROM AUTHOR]

Abstract: Wireless data broadcast is an important data dissemination method for distributing public information to mobile users. Due to the exponentially increasing number of mobile network users, it is necessary to develop efficient data retrieval protocols for end users to download data items effectively. In this paper, we concentrate on investigating scheduling algorithms for retrieving a set of data items from a multichannel wireless data broadcast system. As we know, the most important issues in mobile computing are energy efficiency and query response efficiency. However, in data broadcast the objectives of reducing access latency and energy cost can be contradictive to each other. Consequently, we define a new problem named Minimum Constraint Data Retrieval Problem (MCDR). We prove that MCDR is NP-hard, and then show a fixed parameter tractable algorithm which can balance two factors together. It has computational time , where is the number of channels, is the number of required data items, is the maximal time slot, and is the maximal number of channel switches. [Copyright &y& Elsevier]

This work addresses the radio resource allocation problem for cooperative relay assisted OFDMA wireless network. The relays adopt the decode-and-forward protocol and can cooperatively assist the transmission from source to destination. Recent works on the subject have mainly considered symmetric source-to-relay and relay-to-destination resource allocations, which limits the achievable gains through relaying. In this paper we consider the problem of asymmetric radio resource allocation, where the objective is to maximize the system throughput of the source-to-destination link under various constraints. In particular, we consider optimization of the set of cooperative relays and link asymmetries together with subcarrier and power allocation. We derive theoretical expressions for the solutions and illustrate them through simulations. The results show clear additional performance gains through asymmetric cooperative scheme compared to the other recently proposed resource allocation schemes. [ABSTRACT FROM AUTHOR]

Channel assignment is a crucial problem for wireless networks, especially for noncooperative wireless networks, in which nodes are selfish. While there have been a few studies of noncooperative, multiradio channel assignment, most existing studies are restricted to single collision domains only. In this paper, we study the design of incentive-compatible protocols for noncooperative, multiradio channel assignment in multiple collision domains. First, we show the necessity of designing incentive-compatible protocols for this problem. Specifically, we show that, if no incentive-compatible protocol is deployed, Nash Equilibria (NEs) may have undesired properties, such as Pareto suboptimality and low throughput. To prevent the system from converging to the NEs with undesired properties, we propose an incentive-compatible protocol for channel assignment in multiple collision domains. We rigorously show that our protocol guarantees that the system converges to NEs that are Pareto-optimal and have the maximum system-wide throughput. Our simulation results also verify that our protocols are effective in ensuring that the system converges to the desired NEs. [ABSTRACT FROM AUTHOR]

Wireless USB (WUSB) is the USB technology merged with WiMedia PHY /MAC. WUSB can be applied to wireless personal area network applications as well as PAN applications like wired USB. However, due to mobility of WUSB devices in multi-hop environment, DRP (distributed reservation protocol) reservation conflicts happen frequently among WUSB devices with three-hop distance. To solve this problem in large scale WUSB networks, we propose a new DRP reservation scheme using dual role devices and a new Operation Info bits for three-hop mobility support. It is shown by simulation and numerical results that throughputs of WUSB devices at three-hop range hidden DRP reservation conflicts are largely increased. [ABSTRACT FROM AUTHOR]

In this paper we raise and discuss a problem from the analysis done in Moen et al. (ACM SIGMOBILE Comput Commun Rev 8(2):76-83, ) about some weaknesses in the key scheduling in Wi-Fi protected access (WPA). [ABSTRACT FROM AUTHOR]

Widespread deployment of wireless local area networks and a gradual increase in streaming applications have brought about a demand for improved quality of service (QoS) in wireless networks. However, increasing user datagram protocol based high priority multimedia traffic and the class differentiation introduced in QoS protocols, has resulted into transmission control protocol (TCP) starvation and increased spurious timeouts. While today's Internet traffic is still dominated by TCP based applications, the negative effects of IEEE 802.11e enhanced distributed coordination function (EDCF) scheme on TCP performance in the presence of high priority traffic have not been extensively explored. In this paper, the performance of TCP in 802.11e WLAN competing with high priority traffic is examined. The prioritised adaptive enhanced scheme (PAD_EDCF) is proposed. The proposed scheme gives priority to TCP control packets in order to improve the low traffic transmission flow and acquires additional capability of adjusting the MAC parameters based on the traffic load condition. Simulation results demonstrate that the proposed scheme significantly improves TCP performances in terms of traffic efficiency, throughput and reduces delay. [ABSTRACT FROM AUTHOR]

Abstract: The underground communication in tunnels and mines is very challenging due to the hostile nature of the environments and to the propagation issues that electromagnetic waves suffer there. Communication is often unidirectional (e.g. in mines) or very costly (e.g. leaky feeder in road tunnels) and hard to install and maintain. This work proposes the use of multi-hop ad-hoc networks to provide multimedia communication between mobile nodes in such a hostile environments, relying on a complete hardware/software, cheap and easy-to-setup platform that can be used both as temporary or fixed infrastructure or as communication backbone in emergency scenarios like mine accidents or a tunnel collapse. The communication is based on the Real-Time Multi-hop Protocol (RT-WMP) and its QoS extension executed over several nodes equipped with specific hardware. This protocol manages delay sensitive messages and the node mobility across the network while the QoS extension is responsible for allowing the end-to-end voice communication. The specific topology and situation have driven to a specialization of RT-WMP to better perform in this type of environments, taking advantage of the a priori (partial) knowledge about the topology. This proposal was tested in a real application in the Somport tunnel, the about 8km-long railroad linking Canfranc, Spain with Pau, France. [Copyright &y& Elsevier]

Interference constitutes a major challenge to availability for communication networks operating over a shared medium. This paper proposes the medium access (MAC) protocol AntiJam, which achieves a high and fair throughput even in harsh environments. Our protocol mitigates internal interference, requiring no knowledge about the number of participants in the network. It is also robust to intentional and unintentional external interference, e.g., due to coexisting networks or jammers. We model external interference using a powerful reactive adversary that can jam a (1-\varepsilon)-portion of the time-steps, where 0<\varepsilon\leq 1 is an arbitrary constant. The adversary uses carrier sensing to make informed decisions on when it is most harmful to disrupt communications. Moreover, we allow the adversary to be adaptive and to have complete knowledge of the entire protocol history. AntiJam makes efficient use of the nonjammed time periods and achieves, if \varepsilon is constant, a \Theta(1)-competitive throughput. In addition, AntiJam features a low convergence time and has excellent fairness properties, such that channel access probabilities do not differ among nodes by more than a small constant factor. [ABSTRACT FROM PUBLISHER]

Wireless sensor networks are composed by large number of small battery powered sensors distributed in an environment. They are responsible to monitor and transmit its physical characteristics. These networks require robust wireless communication protocols that are energy efficient. Thus, it is a challenge for the self organization protocols to provide network survivability and redundancy features. In this paper, we present a novel clustering algorithm called HDED (hybrid distributed, energy-efficient, and dual homed clustering Algorithm), derived from DED (distributed, energy-efficient, and dual homed clustering) which aims some changes on this protocol to increase its performance. Better coverage, energy efficiency, minimum traffic from nodes to base station, balanced energy consumption are the main features of HDED to improve life time of WSN. Simulation results confirm that HDED is effective in prolonging the network lifetime as well as in improving throughput, than DED and EDED. [ABSTRACT FROM AUTHOR]

Cooperative relaying has been well appreciated to be a key concept of future wireless systems capable of yielding high network reliability and significant error rate reduction. However, in such paradigm of communication, the total limited power may be wasted without providing minimum performance requirements such as network lifetime if it is not well allocated between the cooperating nodes in an efficient way. In this work, we mainly address the problem of network lifetime limitation in wireless relay communication system by developing optimal power allocation techniques. In the communication scenario, a source sends information to a destination with the help of multiple relay nodes operating in amplify-and-forward relaying protocol. As a parameter of measurement, we particularly address the symbol error rate (SER) performance for MPSK signal using the concept of moment generating function. Due to the complexity of the closed-form SER expression, we then find a tight corresponding lower bound to show useful insights in terms of analysis. Next, we develop a cooperation strategy where only a best relay that maximizes the end-to-end signal-to-noise ratio assists the transmission to further improve the performance of the previous system. In addition, numerical results are presented to validate the theoretical analysis. [ABSTRACT FROM AUTHOR]

In recent years, many studies have proposed various ways to strengthen wireless networks' performance. In this paper, we identify some drawbacks arising from protocol improved location-aided routing (ILAR). Nodes around the borders of a given broadcast coverage might quickly and easily move out, resulting in a broken routing path. Another problem in ILAR is that, although it may have a better forwarding node available for use a relay node could fail. Therefore we propose a novel routing protocol integrated power balance scheme to help resolve the problems mentioned above. Furthermore, the scheme employs position information and a power-saving scheme to balance the energy of each node and to lengthen the entire network's life. To achieve these goals, there must be a reduction in the simultaneous loading of networks. Therefore, we also propose a cluster-based routing mechanism in mobile ad hoc networks. This mechanism can reduce the loading of networks, energy conservation, and increase the lifetime of nodes and networks. [ABSTRACT FROM AUTHOR]

Abstract: Security protocols operating over wireless channels can incur significant communication costs (e.g., energy, delay), especially under adversarial attacks unique to the wireless environment such as signal jamming, fake signal transmission, etc. Since wireless devices are resource constrained, it is important to optimize security protocols for wireless environments by taking into account their communication costs. Towards this goal, we first present a novel application of a signal-flow-based approach to analyze the communication costs of security protocols in the presence of adversaries. Our approach models a protocol run as a dynamic probabilistic system and then utilizes Linear System theory to evaluate the moment generating function of the end-to-end cost. Applying this technique to the problem of secret key exchange over a wireless channel, we quantify the efficiency of existing families of key exchange cryptographic protocols, showing, for example, that an ID-based approach can offer an almost 10-fold improvement in energy consumption when compared to a traditional PKI-based protocol. We then present a new key exchange protocol that combines traditional cryptographic methods with physical-layer techniques, including the use of “ephemeral” spreading codes, cooperative jamming, and role-switching. Utilizing signal flow analysis, we demonstrate that this new protocol offers performance advantages over traditional designs. [Copyright &y& Elsevier]

We study the capacity scaling laws for the cognitive network that consists of the primary hybrid network (PhN) and secondary ad hoc network (SaN). PhN is further comprised of an ad hoc network and a base station-based (BS-based) network. SaN and PhN are overlapping in the same deployment region, operate on the same spectrum, but are independent with each other in terms of communication requirements. The primary users (PUs), i.e., the ad hoc nodes in PhN, have the priority to access the spectrum. The secondary users (SUs), i.e., the ad hoc nodes in SaN, are equipped with cognitive radios, and have the functionalities to sense the idle spectrum and obtain the necessary information of primary nodes in PhN. We assume that PhN adopts one out of three classical types of strategies, i.e., pure ad hoc strategy, BS-based strategy, and hybrid strategy. We aim to directly derive multicast capacity for SaN to unify the unicast and broadcast capacities under two basic principles: 1) The throughput for PhN cannot be undermined in order sense due to the presence of SaN. 2) The protocol adopted by PhN does not alter in the interest of SaN, anyway. Depending on which type of strategy is adopted in PhN, we design the optimal-throughput strategy for SaN. We show that there exists a threshold of the density of SUs according to the density of PUs beyond which it can be proven that: 1) when PhN adopts the pure ad hoc strategy or hybrid strategy, SaN can achieve the multicast capacity of the same order as it is stand-alone; 2) when PhN adopts the BS-based strategy, SaN can asymptotically achieve the multicast capacity of the same order as if PhN were absent, if some specific conditions in terms of relations among the numbers of SUs, PUs, the destinations of each multicast session in SaN, and BSs in PhN hold. [ABSTRACT FROM AUTHOR]

Abstract: As the demand for mobile ad hoc wireless network (MANET) applications grows, so does their use for many important services where reliability and stability of the communication paths are of great importance. Therefore, a MANET must be able to establish reliable communication channels which are protected by failure recovery protocols. One approach for existing failure recovery protocols is based on using backup paths, or multi-paths. This technique provides for more stable communication channels for wireless services, in particular for MANET applications. But work on such multi-path protocols has focused on stability in the presence of link failure for MANETs. In this paper, we extend such protocols to maintain connection stability in the presence of node failure. Our work is focused on protecting the route of mobile wireless communications in the presence of node failure in order to improve their use in MANETs applications by discovering efficient stable communication channels with longer lifetimes and increased number of packets delivered. [Copyright &y& Elsevier]

Abstract: This paper considers a field with a number of isolated wireless sensor networks served by some mobile mules and base stations (BSs). Sensing data needs to be carried by mobile mules to BSs via opportunistic contact between them. Also, such contact may not be frequent. Thus there are four types of communications in this environment: (i) inter-node communications within a WSN, (ii) opportunistic WSN-to-mule communications, (iii) opportunistic mule-to-mule communications, and (iv) opportunistic mule-to-BS communications. In such disconnected WSNs, since sensors’ memory spaces are limited and data collection from isolated WSNs to mules and then to BSs relies on opportunistic communications in the sense that contact between these entities is occasional, storing and collecting higher-priority data is necessary. Therefore, there are two critical issues to be addressed: the data storage management in each isolated WSN and opportunistic data collection between these entities. We address the storage management problem by modeling the limited memory spaces of a WSN’s sensor nodes as a distributed storage system. Assuming that there is a sink in the WSN that will be visited by mobile mules occasionally, we address three issues: (i) how to buffer sensory data to reduce data loss due to a shortage of storage spaces, (ii) if dropping of data is inevitable, how to avoid higher-priority data from being dropped, and (iii) how to manage the data nearby the sink to facilitate the downloading jobs of mules when the downloading time is unpredictable. We propose a Distributed Storage Management (DSM) strategy based on a novel shuffling mechanism similar to heap sort. It allows nodes to exchange sensory data with neighbors efficiently in a distributed manner. For the opportunistic data collection problem, based on a utility model, we then develop an Opportunistic Data Exchange (ODE) strategy to guide two mules to exchange data that would lead to a higher reward. To the best of our knowledge, this is the first work addressing distributed storage strategy for isolated WSNs with opportunistic communications using mobile mules. We conduct extensive simulations to investigate the merit of DSM and ODE. The simulation results indicate that the level of data importance collected by our DSM is very close to a global optimization and our ODE could facilitate delivery of important data to BSs through mules. We also implement these strategies in a real sensor platform, which demonstrates that the simple and lightweight protocols can achieve our goals. [Copyright &y& Elsevier]

his paper proposes a time-frequency-based fingerprinting identification approach by extracting the transient characterizations regarding highly integrated wireless local area network (WLAN) cards. The transient energy envelope is derived from the slice of spectrogram in the time-frequency domain. Then this transient response is fitted to a polynomial under least square criteria, and the polynomial coefficients are regarded as the feature vector. A data acquisition system has been set up to capture IEEE 802.11b Wi-Fi (wireless fidelity) signals. The results exhibit an approving distinctiveness of up to 94% to classify different manufactories of WLAN cards and of 78.4% for the WLAN cards of the same manufactory. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

SUMMARY Password-authenticated group key exchange protocols enable communication parties to establish a common secret key (a session key) by only using short secret passwords. Such protocols have been receiving significant attention. This paper shows some security weaknesses in some recently proposed password-authenticated group key exchange protocols. Furthermore, a secure and efficient password-authenticated group key exchange protocol in mobile ad hoc networks is proposed. It only requires constant round to generate a group session key under the dynamic scenario. In other words, the overhead of key generation is independent of the size of a total group. Further, the security properties of our protocol are formally validated by a model checking tool called AVISPA. Security and performance analyses show that, compared with other related group key exchange schemes, the proposed protocol is also efficient for real-world applications in enhancing the security over wireless communications. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Authenticating spontaneous interactions between devices and users is challenging for several reasons: the wireless (and therefore invisible) nature of device communication, the heterogeneous nature of devices, and lack of appropriate user interfaces in mobile devices, and the requirement for unobtrusive user interaction. The most promising approach that has been proposed in literature involves the exploitation of the so-called auxiliary channels for authentication to bridge the gap between usability and security. This concept has spawned the independent development of various authentication methods and research prototypes, that, unfortunately, remain hard to compare and interchange and are rarely available to potential application developers. We present a novel, unified cryptographic authentication protocol framework (UACAP) to unify these approaches on using auxiliary channels and analyze its security properties. This protocol and a selection of auxiliary channels aimed at authentication of mobile devices has been implemented and released in an open-source ubiquitous authentication toolkit (OpenUAT). We also present an initial user study evaluating four of these channels. [ABSTRACT FROM AUTHOR]

Multihop wireless broadcast is an important component in vehicular networks. Many applications are built on broadcast communications, so efficient routing methods are critical for their success. Here, we develop the Distribution-Adaptive Distance with Channel Quality (DADCQ) protocol to address this need and show that it performs well compared to several existing multihop broadcast proposals. The DADCQ protocol utilizes the distance method to select forwarding nodes. The performance of this method depends heavily on the value of the decision threshold, but it is difficult to choose a value that results in good performance across all scenarios. Node density, spatial distribution pattern, and wireless channel quality all affect the optimal value. Broadcast protocols tailored to vehicular networking must be adaptive to variation in these factors. In this work, we address this design challenge by creating a decision threshold function that is simultaneously adaptive to the number of neighbors, the node clustering factor, and the Rician fading parameter. To calculate the clustering factor, we propose using the quadrat method of spatial analysis. The resulting DADCQ protocol is then verified with JiST/SWANS and shown to achieve high reachability and low bandwidth consumption in urban and highway scenarios with varying node density and fading intensity. [ABSTRACT FROM AUTHOR]

In this paper we propose high throughput collision free, mobility adaptive and energy efficient medium access protocol (MAC) called Collision Free Mobility Adaptive (CFMA) for wireless sensor networks. CFMA ensures that transmissions incur no collisions, and allows nodes to undergo sleep mode whenever they are not transmitting or receiving. It uses delay allocation scheme based on traffic priority at each node and avoids allocating same backoff delay for more than one node unless they are in separate clusters. It also allows nodes to determine when they can switch to sleep mode during operation. CFMA for mobile nodes provides fast association between the mobile node and the cluster coordinator. The proposed MAC performs well in both static and mobile scenarios, which shows its significance over existing MAC protocols proposed for mobile applications. The performance of CFMA is evaluated through extensive simulation, analysis and comparison with other mobility aware MAC protocols. The results show that CFMA outperforms significantly the existing CSMA/CA, Sensor Mac (S-MAC), Mobile MAC (MOB-MAC), Adaptive Mobility MAC (AM-MAC), Mobility Sensor MAC (MS-MAC), Mobility aware Delay sensitive MAC (MD-MAC) and Dynamic Sensor MAC (DS-MAC) protocols including throughput, latency and energy consumption. [ABSTRACT FROM AUTHOR]

Idle listening is one of the main factors for energy consumption in wireless sensor networks, and the duty cycle mechanism is widely used to reduce idle listening. In this paper, we present a new receiver-initiated duty cycling MAC protocol for wireless sensor networks, called reordering-passive MAC (RP-MAC), which includes receiver wake-up time estimation scheme and frame reordering scheme. We evaluate the performance of RP-MAC in ns-2 network simulator, and the simulation results shows that RP-MAC achieves higher energy efficiency, higher network throughput and lower end-to-end delay compared to other passive protocols, especially in case of heavy traffic or low duty cycle. [ABSTRACT FROM AUTHOR]

IPv6 mobility management is one of the most challenging research topics for enabling mobility service in the forthcoming mobile wireless ecosystems. The Internet Engineering Task Force has been working for developing efficient IPv6 mobility management protocols. As a result, Mobile IPv6 and its extensions such as Fast Mobile IPv6 and Hierarchical Mobile IPv6 have been developed as host-based mobility management protocols. While the host-based mobility management protocols were being enhanced, the network-based mobility management protocols such as Proxy Mobile IPv6 (PMIPv6) and Fast Proxy Mobile IPv6 (FPMIPv6) have been standardized. In this paper, we analyze and compare existing IPv6 mobility management protocols including the recently standardized PMIPv6 and FPMIPv6. We identify each IPv6 mobility management protocol's characteristics and performance indicators by examining handover operations. Then, we analyze the performance of the IPv6 mobility management protocols in terms of handover latency, handover blocking probability, and packet loss. Through the conducted numerical results, we summarize considerations for handover performance. [ABSTRACT FROM PUBLISHER]

Abstract: In this paper, the hardware implementations of six representative stream ciphers are compared in terms of performance, consumed area and the throughput-to-area ratio. The stream ciphers used for the comparison are ZUC, Snow3g, Grain V1, Mickey V2, Trivium and E0. ZUC, Snow3g and E0 have been used for the security part of well known standards, especially wireless communication protocols. In addition, Grain V1, Mickey V2 and Trivium are currently selected as the final portfolio of stream ciphers for Profile 2 (Hardware) by the eStream project. The designs were implemented by using VHDL language and for the hardware implementations a FPGA device was used. The highest throughput has been achieved by Snow3g with 3330Mbps at 104MHz and the lowest throughput has been achieved by E0 with 187Mbps at 187MHz. Also, the most efficient cipher for hardware implementation in terms of throughput-to-area ratio is Mickey V2 cipher while the worst cipher for hardware implementation is Grain V1. [Copyright &y& Elsevier]

Mobile ad hoc network is a collection of multi hop wireless mobile nodes that communicates with each other without centralized control or established infrastructure. It is the network with dynamically and frequently changing topologies as each node in it moves. Due to a no. of constraints in self organizing and self operating networks, routing. It is a challenging problem. To find optimum routes with minimum control overhead and networks resources, there are a lot of routing protocols namely DSDV, DSR, AODV etc. This review paper gives a review of existing routing protocols by giving their characteristics, functionality, benefits, limitations and the comparison between them. [ABSTRACT FROM AUTHOR]

Radio Frequency Identification (RFID) is a technology that is very popular due to the simplicity in its technology and high adaptability in a variety of areas. The simplicity in the technology, however, comes with a caveat - RFID tags have severe resource restrictions, which make them vulnerable to a range of security attacks. Such vulnerability often results in the loss of privacy of the tag owner and other attacks on tags. Previous research in RFID security has mainly focused on authenticating entities such as readers / servers, which communicate with the tag. Any security mechanism is only as strong as the encryption keys used. Since RFID communication is wireless, critical messages such as key exchange messages are vulnerable to attacks. Therefore, we present a mutual authentication protocol that relies on independent generation and dynamic updates of encryption keys thereby removing the need for key exchange, which is based on the concept of gene mutation and transfer. We also present an enhanced version of this protocol, which improves the security offered by the first protocol. The novelty of the proposed protocols is in the independent generation, dynamic and continuous updates of encryption keys and the use of the concept of gene mutation / transfer to offer mutual authentication of the communicating entities. The proposed protocols are validated by simulation studies and security analysis. [ABSTRACT FROM AUTHOR]

Many wireless sensor network applications require sensor nodes to be deployed on the ground or other surfaces. However, there has been little effort to characterize the large- and small-scale path loss for surface-level radio communications. We present a comprehensive measurement of path loss and fading characterizes for surface-level sensor nodes in the 400 MHz band in both flat and irregular outdoor terrain in an effort to improve the understanding of surface-level sensor network communications performance and to increase the accuracy of sensor network modeling and simulation. Based on our measurement results, we characterize the spatial small-scale area fading effects as a Rician distribution with a distance-dependent K-factor. We also propose a new semi-empirical path loss model for outdoor surface-level wireless sensor networks called the Surface-Level Irregular Terrain (SLIT) model. We verify our model by comparing measurement results with predicted values obtained from high-resolution digital elevation model (DEM) data and computer simulation for the 400 MHz and 2.4 GHz band. Finally, we discuss the impact of the SLIT model and demonstrate through simulation the effects when SLIT is used as the path loss model for existing sensor network protocols. [ABSTRACT FROM AUTHOR]

In a multi-hop ad hoc network, nodes contend for shared wireless channel with neighbors. The contention results in congestion and greatly degrades the performance of a network due to severe packet collisions. Several papers have shown that the performance of multi-hop ad hoc network is poor and the IEEE 802.11 scheme fails to achieve optimum scheduling for medium access contention. In this paper, we present a multi-hop packet scheduling framework to achieve high throughput, good packet delivery ratio, low routing load, and small link-failure probability in ad hoc environment. The routing information about the total hop count and the remaining hop count, required by a packet to reach its destination, is exploited by this scheme in the MAC layer to recalculate the contention window size of the nodes along routing path and to give priorities for the packets that are closer to their destination. Extensive simulations show that the proposed scheme is able to earn significant improvement over the conventional algorithm. [ABSTRACT FROM AUTHOR]

A group key agreement protocol is a group communication mechanism that allows a set of parties to determine a group key used for encrypting/decrypting subsequent communication messages through an insecure channel. Based on the rapid development of wireless and mobile technologies, researchers have proposed several group key protocols for mobile environments. In these protocols, the computational cost of each mobile device is fixed, but each mobile user must hold the public keys of all other users. This study proposes an identity-based authenticated group key agreement protocol for mobile environments based on bilinear pairings. In the proposed scheme, the public key of the user can be easily derived from the user's identity. Therefore, each user is not required to hold the public keys of the other entities. In this approach, the computational cost of each mobile user is independent of the number of mobile users; that is, the computational cost of each mobile user is fixed. The proposed protocol meets the usual security requirements and resists well-known attacks. [ABSTRACT FROM AUTHOR]

We propose and analyze a cross-layer integrated mobility and service management scheme called DMAPwSR in Mobile IPv6 environments with the goal to minimize the overall mobility and service management cost for serving mobile users with diverse mobility and service characteristics. The basic idea of DMAPwSR is that each mobile node (MN) can utilize its cross-layer knowledge to choose smart routers to be its dynamic mobility anchor points (DMAPs) to balance the cost associated with mobility services versus packet delivery services. These smart routers are just access routers for MIPv6 systems except that they are capable of processing binding messages from the MN and storing the current location of the MN in the routing table for forwarding service packets destined to the MN. The MN's DMAP changes dynamically as the MN roams across the MIPv6 network. Furthermore the DMAP service area also changes dynamically reflecting the MN's mobility and service behaviors dynamically. Unlike previous mobility management protocols such as HMIPv6 that focus only on mobility management, DMAPwSR considers integrated mobility and service management. We develop an analytical model based on stochastic Petri nets to analyze DMAPwSR and compare its performance against MIPv6 and HMIPv6. We validate analytical solutions obtained through extensive simulation including sensitivity analysis of simulation results with respect to the network coverage model, the MN's residence time distribution and the DMAP service area definition. [ABSTRACT FROM AUTHOR]

Broadband wireless technologies will soon become an integral part of daily life. In this paper we present the design rationale of a context-aware mobility management architecture for seamless handover in heterogeneous networks. Our proposal is a new cross-layer and interactive approach to seamless handover of users and their services. We present a simple though effective analytical model in typical deployment scenarios in heterogeneous networks with the use of the IEEE Media Independent Handover services. Such analytical model is used to evaluate the resulting handover delay when deploying common mobility protocols in our architecture, such as Mobile IP, Hierarchical MIP, and Proxy MIP. [ABSTRACT FROM AUTHOR]

Abstract: Due to their potential to create and extend pervasive communication applications to cognitive environments with distributed control, the emerging technology of cognitive wireless mesh networks is gaining significant attention from a growing research community. However, the major challenge in cognitive networks is the adaptation to time and space variability of the available resources, namely chunks of the frequency spectrum called channels. In particular, this problem is exacerbated in cognitive mesh networks because there exists no direct communication among devices which thereby cannot establish a global (common) control channel to coordinate the entire network. Instead, only local control channels that vary depending on the time instant and location, can be established to coordinate cognitive devices among themselves. This paper first analyzes the underlying challenges and existing approaches to address the absence of a static and global control channel, and then propose a novel Control channel formation protocol, called Connor. Our protocol Connor is a fully distributed coordination scheme where cognitive mesh devices self-organize into clusters based on the similarity of available channels and on topological constraints. Compared with the existing clustering algorithms, which requires synchronization, the proposed Connor performs better in most cases without imposing synchronization. [Copyright &y& Elsevier]

We propose a model-based description and analysis framework for the design of wireless system architectures. Its aim is to address the shortcomings of existing approaches to system verification and the tracking of anomalies in safety-critical wireless systems. We use Architecture Analysis and Description Language (AADL) to describe an analysis-oriented architecture model with highly modular components. We also develop the cooperative tool chains required to analyze the performance of a wireless system by simulation. We show how this framework can support a detailed and largely automated analysis of a complicated, networked wireless system using examples from wireless healthcare and video broadcasting. [ABSTRACT FROM PUBLISHER]

Multi-Radio Cooperative Automatic Retransmission Request (MC-ARQ) schemes are introduced in this paper within the context of hybrid networks combining long-range and short-range communications. Since the number of wireless devices is incessantly increasing, it is frequently possible to establish a spontaneous cooperative cluster in the close proximity of any wireless device. These devices forming the cluster are connected to both a cellular-based network such as WiMAX, 3G, or LTE and a short-range network based on technologies such as WLAN, Zigbee, Bluetooh, or UWB, among other possibilities. The main idea behind the proposed MC-ARQ scheme is that, upon transmission error through the cellular interface, retransmission can be requested from the wireless grid surrounding the destination device using the short-range interface instead of the primary cellular link. Therefore, besides the cooperative diversity attained with C-ARQ schemes, the traffic load in the cellular interface is reduced benefiting thus a high number of users and reducing both energy consumption and interference. The Persistent Relay Carrier Sensing Medium Access (PRCSMA) protocol is presented as an example of solution for the MAC layer in this emerging new topic. [ABSTRACT FROM AUTHOR]

Environment monitoring is an important wireless sensor network application. A traditional method for such applications is to deploy sensors all over a region and aim to cover as much area as possible. However, this method is not only a great waste of money and resources, but also unnecessary and unrealistic. It also invokes many data collisions and places a serious burden on the network protocols. In this paper, we propose a critical line based environment surveillance strategy. We deploy sensors along critical lines instead of all over the region. Our aim is to capture or detect a target or target event rather than tracking it. As coverage is an important factor impacting monitoring, we study boundary coverage capability under several conditions and consider different deployments of sensors. We also compare our surveillance strategy to the traditional one, and the results show that our strategy saves many sensors. Furthermore, we abstract a model of the problem, which provides an optimizing solution to surveillance applications. [ABSTRACT FROM AUTHOR]

With the explosive growth and wide-spread use of smartphones with Wi-Fi enabled, people are used to accessing the internet through Wi-Fi network interfaces of smartphones. Smartphones periodically transmit Wi-Fi messages, even when not connected to a network. In this paper, we describe the Mo-Fi system which monitors and aggregates large numbers of continuous Wi-Fi message transmissions from nearby smartphones in the area of interest using nonintrusive Wi-Fi sniffer sensors. In this paper, we propose an optimized Wi-Fi channel detection and selection method to switch the best channels automatically to aggregate the Wi-Fi messages based on channel data transmission weights and human presence activity classification method based on the features of human dwell duration sequences in order to evaluate the user engagement index. By deploying in the real-world office environment, we found that the performance of Wi-Fi messages aggregation of CAOCA and CACFA algorithms is over 3.8 times higher than the worst channel of FCA algorithms and about 76% of the best channel of FCA algorithms, and the human presence detection rate reached 87.4%. [ABSTRACT FROM AUTHOR]

In wireless sensor networks (WSN), Sybil attack can destroy the routing and data distributed storage mechanisms through fabricating identity information of legitimate nodes. This paper presents a chain key predistribution based approach against Sybil attack. To enhance the security of common keys between neighboring nodes, during the chain key predistribution phase, our approach uses a lightweight hash function to generate several chain keys by hashing the unique identity information of every node sequentially in the trusted base station. These chain keys construct a pool of chain keys. During the pairwise key authentication establishment phase, a node-to-node chain key based authentication and exchange (CK-AE) protocol is proposed, by which each node can share the unique pairwise key with its neighboring node. The CK-AE protocol is provably secure in the universally composable security model (UCSM). Finally, we analyze our approach from the resilience of network and the performance overhead, and the results show that our approach can not only enhance the ability of resilience to Sybil attack, but also reduce the communication overhead significantly at the cost of a certain amount of computational overhead. [ABSTRACT FROM AUTHOR]

The vehicular mobility is reflection and extension of the human social activity. Since human trajectories show a high degree of temporal and spatial regularity, thus vehicular driving paths are predictable to a large extent. In this paper, we firstly analyze the predictabilities of different types of vehicles and then propose a new driving path predication based routing protocol (DPPR). With hello messages to broadcast vehicles' driving path predication information to neighbor vehicles, DPPR can observably increase the successful ratio to find the proper next hop vehicles that move toward the optimal expected road in intersection areas. In roads with sparse vehicle density, DPPR utilizes vehicles to carry messages to roads with high vehicle density while the messages' forward paths partially coincide with the vehicles' driving paths. Moreover, as to messages that can tolerate long delay, they can be carried to destinations by vehicles whose driving paths will pass the messages' destination in order to optimize bandwidth utilization. Simulation results demonstrate the effectiveness of the proposed DPPR protocol. [ABSTRACT FROM AUTHOR]

Intervehicle communication gives vehicles opportunities to exchange packets within the limited radio range and self-organized in Ad Hoc manner into VANETs (Vehicular Ad Hoc Networks). However, due to issues such as the high mobility, insufficient market penetration ratio, and lacking of roadside units, connectivity is actually a big problem in VANETs. In addition, relying only on the direct connectivity in most of the previous works, say broadcasting which provides one-hop connections between nodes is far from the continuously growing application demands in VANETs, such as inter-vehicle entertainments, cooperative collision avoidances, and inter-vehicle emergency notifications. Therefore, the indirect connectivity from multihop forwarding is also a necessary complement especially for the case where direct connection is hardly achieved. In this paper, we define a new metric, that is, available connectivity, to consider both direct and indirect connectivity. After analyzing the statistical properties of direct and indirect connectivity in vehicular environment, the available connectivity is proposed and quantified for practical usage. Numerical results show that our available connectivity could provide correct and useful references for protocols design and performance improvements of different applications. [ABSTRACT FROM AUTHOR]

Due to the potentials in promoting the driving safety and easing the traffic congestion, vehicular networks, especially vehicle-to-vehicle (V2V) communications, have recently been receiving much attention. The data dissemination protocol for V2V applications should not only provide end-to-end transmissions with low error probability and high throughput but also offer antieavesdropping capabilities. To achieve this goal, we in this paper propose a secrecy-enhanced relaying protocol for vehicular environments. Based on the network topology and the velocity of the moving vehicles, the proposed scheme first generates the relay candidate set, from which a single relay is then selected opportunistically to assist the source. By using the superposition coding strategy, the selected relay jointly sends the source message and the artificial interference to enable secure communications. We derive the tight closed-form expressions for the upper and lower bounds of the secrecy outage probability, based on which we analyze the diversity order of the system. The method to generate the interference signal is introduced, and the choice of superposition weight factor is also given. The analytical and simulation results show that the proposed relay-aided protocol yields a better performance than the competing alternatives in terms of both the secrecy performance and the implementation complexity. [ABSTRACT FROM AUTHOR]