Showing papers in "Wireless Personal Communications in 2011"

Internet of Things: Applications and Challenges in Technology and Standardization

Abstract: The phrase Internet of Things (IoT) heralds a vision of the future Internet where connecting physical things, from banknotes to bicycles, through a network will let them take an active part in the Internet, exchanging information about themselves and their surroundings. This will give immediate access to information about the physical world and the objects in it--leading to innovative services and increase in efficiency and productivity. This paper studies the state-of-the-art of IoT and presents the key technological drivers, potential applications, challenges and future research areas in the domain of IoT. IoT definitions from different perspective in academic and industry communities are also discussed and compared. Finally some major issues of future research in IoT are identified and discussed briefly.

Security Challenges in the IP-based Internet of Things

Abstract: A direct interpretation of the term Internet of Things refers to the use of standard Internet protocols for the human-to-thing or thing-to-thing communication in embedded networks. Although the security needs are well-recognized in this domain, it is still not fully understood how existing IP security protocols and architectures can be deployed. In this paper, we discuss the applicability and limitations of existing Internet protocols and security architectures in the context of the Internet of Things. First, we give an overview of the deployment model and general security needs. We then present challenges and requirements for IP-based security solutions and highlight specific technical limitations of standard IP security protocols.

A Study on Greenhouse Automatic Control System Based on Wireless Sensor Network

Abstract: The system proposed in this paper collects temperature of leaves and humidity on leaves of crop. As well as greenhouse environmental information such as temperature, humidity, etc. Crop diseases, especially, have deep relationship not only with indoor environmental factors but also with humidity lasting time on leaves and temperature of leaves. Accordingly, monitoring crop itself is as important as monitoring indoor environments. Using these collected greenhouse environmental data, indoor environments can be more effectively controlled, and monitoring crop itself can contribute to improve productivity and to prevent crops from damages by blight and harmful insects. In addition, it will be possible for farmers to do control plant growth through closely studying relationship between indoor environmental information and monitored information on crop itself. Collected data can be stored to database either in server installed in greenhouse or to remote server. It is made possible to collect information and control effectively and automatically greenhouse in the site or from a remote place through web browser. System components are: temperature sensor, humidity sensor, leaf temperature sensor, leaf humidity sensor, Zigbee based wireless sensor node, relay nodes for automatic control, and data server to store greenhouse information. The system is implemented using low power wireless components, and easy to install.

Cluster Based Routing Protocol for Mobile Nodes in Wireless Sensor Network

Abstract: Mobility of sensor nodes in wireless sensor network (WSN) has posed new challenges particularly in packet delivery ratio and energy consumption. Some real applications impose combined environments of fixed and mobile sensor nodes in the same network, while others demand a complete mobile sensors environment. Packet loss that occurs due to mobility of the sensor nodes is one of the main challenges which comes in parallel with energy consumption. In this paper, we use cross layer design between medium access control (MAC) and network layers to overcome these challenges. Thus, a cluster based routing protocol for mobile sensor nodes (CBR-Mobile) is proposed. The CBR-Mobile is mobility and traffic adaptive protocol. The timeslots assigned to the mobile sensor nodes that had moved out of the cluster or have not data to send will be reassigned to incoming sensor nodes within the cluster region. The protocol introduces two simple databases to achieve the mobility and traffic adaptively. The proposed protocol sends data to cluster heads in an efficient manner based on received signal strength. In CBR-Mobile protocol, cluster based routing collaborates with hybrid MAC protocol to support mobility of sensor nodes. Schedule timeslots are used to send the data message while the contention timeslots are used to send join registration messages. The performance of proposed CBR-Mobile protocol is evaluated using MATLAB and was observed that the proposed protocol improves the packet delivery ratio, energy consumption, delay and fairness in mobility environment compared to LEACH-Mobile and AODV protocols.

5G Based on Cognitive Radio

Abstract: Both the cognitive radio (CR) and the fifth generation of cellular wireless standards (5G) are considered to be the future technologies: on one hand, CR offers the possibility to significantly increase the spectrum efficiency, by smart secondary users (CR users) using the free licensed users spectrum holes; on the other hand, the 5G implies the whole wireless world interconnection (WISDOM--Wireless Innovative System for Dynamic Operating Megacommunications concept), together with very high data rates Quality of Service (QoS) service applications. In this paper, they are combined together into a "CR based 5G". With this aim, two novel ideas are advanced: the 5G terminal is a CR terminal and the CR technology is chosen for WISDOM concept. Thus, the 5G takes CR flexibility and adaptability and makes the first step through a commercial and tangible form.

Multi-Source Temporal Data Aggregation in Wireless Sensor Networks

Abstract: Data aggregation has been emerged as a basic approach in wireless sensor networks (WSNs) in order to reduce the number of transmissions of sensor nodes.This paper proposes an energy-efficient multi-source temporal data aggregation model called MSTDA in WSNs. In MSTDA model, a feature selection algorithm using particle swarm optimization (PSO) is presented to simplify the historical data source firstly. And then a data prediction algorithm based on improved BP neural network with PSO (PSO-BPNN) is proposed. This MSTDA model, which helps to find out potential laws according to historical data sets, is deployed at both the base station (BS) and the node. Only when the deviation between the actual and the predicted value at the node exceeds a certain threshold, the sampling value and new model are sent to BS. The experiments on the dataset which comes from the actual data collected from 54 sensors deployed in the Intel Berkeley Research lab made a satisfied performance. When the error threshold greater than 0.15, it can decrease more than 80% data transmissions.

Remote Patient Monitoring Within a Future 5G Infrastructure

Abstract: Systems of wearable or implantable medical devices (IMD), sensor systems for monitoring and transmitting physiological recorded signals, will in future health care services be used for purposes of remote monitoring. Today, there exist several constraints, probably preventing the adoption of such services in clinical routine work. Within a future 5G infrastructure, new possibilities will be available due to improved addressing solutions and extended security services in addition to higher bandwidth in the wireless communication link. Thus 5G solutions can represent a paradigm shift regarding remote patient's monitoring and tracking possibilities, with enhancement in transmitting information between patients and health care services. Some aspects of new possibilities are highlighted in describing a realistic scenario within a future 5G framework.

Cost-Effective Frequency Planning for Capacity Enhancement of Femtocellular Networks

Abstract: The femto-access-point, a low-cost and small-size cellular base-station, is envisioned to be widely deployed in subscribers homes, as to provide high data-rate communications with improved quality of service. As femtocellular networks will co-exist with macrocellular networks, mitigation of the interference between these two network types is a key challenge for successful integration of these two technologies. In particular, there are several interference mechanisms between the femtocellular and the macrocellular networks, and the effects of the resulting interference depend on the density of femtocells and the overlaid macrocells in a particular coverage area. While improper interference management can cause a significant reduction in the system capacity and can increase the outage probability, effective and efficient frequency allocation among femtocells and macrocells can result in a successful co-existence of these two technologies. Furthermore, highly dense femtocellular deployments--the ultimate goal of the femtocellular technology--will require significant degree of self-organization in lieu of manual configuration. In this paper, we present various femtocellular network deployment scenarios, and we propose a number of frequency-allocation schemes to mitigate the interference and to increase the spectral efficiency of the integrated network. These schemes include: shared frequency band, dedicated frequency band, sub-frequency band, static frequency-reuse, and dynamic frequency-reuse. We derive an analytical model, which allows us to analyze in details the users outage probability, and we compare the performance of the proposed schemes using numerical analysis.

Interoperability of Security-Enabled Internet of Things

Abstract: The future Internet will embrace the intelligence of Web 3.0 and the omnipresence of every day connected objects. The later was envisioned as the Internet of Things. Security and interoperability concerns are hindering the service innovations using the Internet of Things. This paper addresses secure access provision to Internet of Things-enabled services and interoperability of security attributes between different administrative domains. In this paper we proposed a layered architecture of Internet of Things framework where a semantically enhanced overlay interlink the other layers and facilitate secure access provision to Internet of Things-enabled services. The main element of semantic overlay is security reasoning through ontologies and semantic rules. Finally the interoperability of security aspect is addressed through ontology and a machine-to-machine platform. This paper provides implementation details of security reasoning and the interoperability aspects and discusses crucial challenges in these areas.

Economic Approaches for Cognitive Radio Networks: A Survey

Abstract: Efficient resource allocation is one of the key concerns of implementing cognitive radio networks. Game theory has been extensively used to study the strategic interactions between primary and secondary users for effective resource allocation. The concept of spectrum trading has introduced a new direction for the coexistence of primary and secondary users through economic benefits to primary users. The use of price theory and market theory from economics has played a vital role to facilitate economic models for spectrum trading. So, it is important to understand the feasibility of using economic approaches as well as to realize the technical challenges associated with them for implementation of cognitive radio networks. With this motivation, we present an extensive summary of the related work that use economic approaches such as game theory and/or price theory/market theory to model the behavior of primary and secondary users for spectrum sharing and discuss the associated issues. We also propose some open directions for future research on economic aspects of spectrum sharing in cognitive radio networks.

Intersection-Based Routing Protocol for VANETs

Abstract: Vehicular ad hoc network (VANET) is an emerging wireless communications technology that is capable of enhancing driving safety and velocity by exchanging real-time transportation information. In VANETs, the carry-and-forward strategy has been adopted to overcome uneven distribution of vehicles. If the next vehicle located is in transmission range, then the vehicle forwards the packets; if not, then it carries the packets until meeting. The carry mostly occurs on sparsely populated road segments, with long carry distances having long end-to-end packet delays. Similarly, the dense condition could have long delays, due to queuing delays. The proposed intersection-based routing protocol finds a minimum delay routing path in various vehicle densities. Moreover, vehicles reroute each packet according to real-time road conditions in each intersection, and the packet routing at the intersections is dependent on the moving direction of the next vehicle. Finally, the simulation results show that the proposed Intersection-Based Routing (IBR) protocol has less end-to-end delay compared to vehicle-assisted data delivery (VADD) and greedy traffic aware routing protocol (GyTAR) protcols.

LUCA: An Energy-efficient Unequal Clustering Algorithm Using Location Information for Wireless Sensor Networks

Abstract: Over the last several years, various clustering algorithms for wireless sensor networks have been proposed to prolong network lifetime. Most clustering algorithms provide an equal cluster size using node's ID, degree and etc. However, many of these algorithms heuristically determine the cluster size, even though the cluster size significantly affects the energy consumption of the entire network. In this paper, we present a theoretical model and propose a simple clustering algorithm called Location-based Unequal Clustering Algorithm (LUCA), where each cluster has a different cluster size based on its location information which is the distance between a cluster head and a sink. In LUCA, in order to minimize the energy consumption of entire network, a cluster has a larger cluster size as increasing distance from the sink. Simulation results show that LUCA achieves better performance than conventional equal clustering algorithm for energy efficiency.

Design and Validation of an Efficient Authentication Scheme with Anonymity for Roaming Service in Global Mobility Networks

Abstract: Designing a user authentication protocol with anonymity for the global mobility network (GLOMONET) is a difficult task because wireless networks are susceptible to attacks and each mobile user has limited power, processing and storage resources. In this paper, a secure and lightweight user authentication protocol with anonymity for roaming service in the GLOMONET is proposed. Compared with other related approaches, our proposal has many advantages. Firstly, it uses low-cost functions such as one-way hash functions and exclusive-OR operations to achieve security goals. Having this feature, it is more suitable for battery-powered mobile devices. Secondly, it uses nonces instead of timestamps to avoid the clock synchronization problem. Therefore, an additional clock synchronization mechanism is not needed. Thirdly, it only requires four message exchanges between the user, foreign agent and home agent. Further, the security properties of our protocol are formally validated by a model checking tool called AVISPA. We also demonstrate that this protocol enjoys important security attributes including prevention of various attacks, single registration, user anonymity, no password table, and high efficiency in password authentication. Security and performance analyses show that compared with other related authentication schemes, the proposed scheme is more secure and efficient.

A Simple and Robust Vertical Handoff Algorithm for Heterogeneous Wireless Mobile Networks

Abstract: Wireless networking is becoming an increasingly important and popular way of providing global information access to users on the move. One of the main challenges for seamless mobility is the availability of simple and robust vertical handoff algorithms, which allow a mobile node to roam among heterogeneous wireless networks. In this paper, motivated by the facts that vertical handoff procedure is done on mobile nodes and battery power may be one crucial parameter for certain mobile nodes, a simple and robust two-step vertical handoff decision algorithm is proposed for heterogeneous wireless mobile networks. To the best of our knowledge, this is the first vertical handoff algorithm that takes the classification of mobile nodes into consideration, one is resource-poor mobile nodes, and the other is resource-rich mobile nodes. This new feature makes it more applicable in the real world. In addition, dynamic new call blocking probability is firstly introduced by this paper to make handoff decision for wireless networks. The experiment results have shown that the proposed algorithm outperforms traditional algorithms in bandwidth utilization, handoff dropping rate and handoff rate.

Reflections on Trust in Devices: An Informal Survey of Human Trust in an Internet-of-Things Context

Abstract: Trust is an essential component of every interaction we make. For some transactions we need very little trust, while for others we may be quite risk averse. In this paper we investigate trust in an Internet-of-Things environment. Can we trust devices? How can we quantify trust in devices?

A Distributed Energy-Aware Routing Protocol for Underwater Wireless Sensor Networks

Abstract: The design of routing protocols for Underwater Wireless Sensor Networks (UWSNs) poses many challenges due to the intrinsic properties of underwater environments. In this paper we present DUCS (Distributed Underwater Clustering Scheme), a new GPS-free routing protocol that does not use flooding techniques, minimizes the proactive routing message exchange and uses data aggregation to eliminate redundant information. Besides, DUCS assumes random node mobility and compensates the high propagation delays of the underwater medium using a continually adjusted timing advance combined with guard time values to minimize data loss. The theoretical and simulation studies carried out demonstrate its effectiveness.

Diversity Analysis of Relay Selection Schemes for Two-Way Wireless Relay Networks

Abstract: One-way wireless relay networks have recently received a lot of attention due to their ability to provide spatial diversity in fading wireless environment. Moreover, performing single-relay selection is a very attractive method due to its cost effective implementation and superior performance. However, one-way relay networks with the half-duplex signalling suffer from a spectral efficiency loss. To overcome such a drawback, two-way wireless relay networks have been proposed and these are also the networks considered in this paper. The paper analyzes the diversity orders of various relay selection schemes, including the best-relay selection, best-worse-channel selection, and maximum-harmonic-mean selection. The analysis is done for the amplify-and-forward protocol and under the two-step and three-step transmission procedures. In particular, it is shown that full diversity orders of R and R + 1 can be achieved in a R-relay wireless network with the two-step and three-step procedures, respectively. Numerical and simulation results are provided to verify our analysis.

Statistical Models for Fading and Shadowed Fading Channels in Wireless Systems: A Pedagogical Perspective

Abstract: A unified analysis of statistical models for describing fading, shadowing, and shadowed fading channels is presented from a pedagogical viewpoint. The different probability density functions such the Rayleigh, Nakagami, gamma, generalized gamma, Weibull, lognormal, Nakagami-lognormal, K distribution, generalized K distribution, and Nakagami inverse Gaussian distribution are presented and the relationships among them are detailed. These density functions are compared in terms of two quantitative measures, namely the amount of fading and outage probability. A general approach to fading and shadowed fading channels using a cluster based approach is also presented to link several of the distributions. It is expected that this overview will be very helpful to students and educators who are engaged in the study of wireless systems and the adverse impact of fading and shadowing in wireless data transmission.

Energy Efficient Wireless Networks Towards Green Communications

Abstract: Wireless networks have become an essential part of the modern life. However, currently, 3% of the world-wide energy is consumed by the ICT infrastructures which causes about 2% of the world-wide CO2 emissions. The transmitted data-volume increases rapidly and wireless communications are used extensively while network design rules have practically ignored the energy efficient network design approach to limit CO2 emissions. This approach is currently named Green Communications. Significant energy savings in mobile networks can be expected by defining and standardizing energy efficiency metrics and combining energy aware flexible radios and networks. This paper discusses several techniques such as cross layer approach, multiple antennas, cell size reduction and cognitive radio, from the system-wide energy efficiency point of view, outlining challenges and open issues.

A Practical Implementation Attack on Weak Pseudorandom Number Generator Designs for EPC Gen2 Tags

Abstract: The Electronic Product Code Generation 2 (EPC Gen2) is an international standard that proposes the use of Radio Frequency Identification (RFID) in the supply chain. It is designed to balance cost and functionality. As a consequence, security on board of EPC Gen2 tags is often minimal. It is, indeed, mainly based on the use of on board pseudorandomness, used to obscure the communication between readers and tags; and to acknowledge the proper execution of password-protected operations. In this paper, we present a practical implementation attack on a weak pseudorandom number generator (PRNG) designed specifically for EPC Gen2 tags. We show that it is feasible to eavesdrop a small amount of pseudorandom values by using standard EPC commands and using them to determine the PRNG configuration that allows to predict the complete output sequence.

Privacy Analysis of Forward and Backward Untraceable RFID Authentication Schemes

Abstract: In this paper, we analyze the first known provably secure Radio Frequency Identification (RFID) authentication schemes that are designed to provide forward untraceability and backward untraceability: the L-K and S-M schemes We show how to trace tags in the L-K scheme without needing to corrupt tags We also show that if a standard cryptographic pseudorandom bit generator (PRBG) is used in the S-M scheme, then the scheme may fail to provide forward untraceability and backward untraceability To achieve the desired untraceability features, we show that the S-M scheme can use a robust PRBG which provides forward security and backward security We also note that the backward security is stronger than necessary for the backward untraceability of the S-M scheme

5G: Service Continuity in Heterogeneous Environments

Abstract: This paper introduces service continuity as the main driver for 5G systems. It addresses user- and service-aspects in recently opened LTE networks, and identifies the system challenges. The main challenges are related to radio coverage, especially for the provision of high data rates for indoor users. The paper covers also network-, user- and service-authentication as well as user and society requirements. 5G is addressed as a system of systems in order to provide service continuity. It addresses both technology challenges, user related issues and operator revenue. Collaborative radio and a system availability beacon are discussed to cope with heterogeneity in 5G. As the SIM card has evolved towards a third-party offering for storage, authentication and payment, functionality of this future SIM is elaborated providing SIM-based service examples. The paper finally addresses service optimization based on light-weight semantic reasoning.

Spectrum Sensing Framework for Cognitive Radio Networks

Abstract: Spectrum sensing feature of cognitive radio devices represents a cornerstone characteristic facilitating real-time and accurate spectrum occupancy measurements in cognitive radio networks. It practically enables the cognitive radio devices to detect vacant spectrum holes and use them for their communication purposes. There are numerous spectrum sensing methods proposed in the literature ranging from local based ones to cooperative strategies among several devices increasing the confidence level of the detected spectrum. This paper gives a general spectrum sensing framework for cognitive radio networks, classifies and explores different spectrum sensing techniques and approaches and shows practical examples, from authors' own experience, of realized spectrum sensing engines and strategies along with some obtained results.

A Street Broadcast Reduction Scheme (SBR) to Mitigate the Broadcast Storm Problem in VANETs

Abstract: In urban vehicular wireless environments, several vehicles can send warning messages and so every vehicle within the transmission range will receive the broadcast transmission, possibly rebroadcasting these messages to other vehicles. This increases the number of vehicles receiving the traffic warning messages. Hence, redundancy, contention, and packet collisions due to simultaneous forwarding (usually known as the broadcast storm problem), can occur. In the past, several approaches have been proposed to solve the broadcast storm problem in wireless networks such as Mobile ad hoc Networks MANETs. In this paper, we present Street Broadcast Reduction SBR, a novel scheme that mitigates the broadcast storm problem in VANETs. SBR also reduces the warning message notification time and increases the number of vehicles that are informed about the alert.

Cloud Based Infrastructure, the New Business Possibilities and Barriers

Abstract: Realization of the cloud computing infrastructure requires access to data anywhere, anytime at any device at a sufficient perceived quality of service. Many Western European countries, such as Denmark, have a high percentage of individuals (inhabitants and companies) that has access to broadband internet via cable, satellite and mobile. This gives a unique position in roll-out and deploying intelligent cloud based services that can be applied for a number of purposes, but where lack of sufficient capacity/quality and IT readiness will be barriers in realization of the "Global Information Multimedia Communication Village (GIMCV)". Broadband is here defined as more than 2 Mbps. In this paper, the combination of e-commerce, cloud computing and broadband infrastructure has our focus, and its unique possibilities for the overall IT society. However, it is also about a significant number of Small and Medium sized Enterprises (SMEs) that today applies manual billing systems or Excel like systems in combination with severe lacks of sufficient IT skills. This means that the most commonly used systems are the ones requiring the most of our time. Therefore, the move for the SME towards e-commerce and electronic processes has a significant economical potential for the SMEs. E-commerce and other internet based services will simplify their business, and hence allow the SMEs to focus on their core business which was their raison d'etre. In addition to this can be added other fundamental IT systems that will help their business, but that is outside the scope of this paper. Furthermore, this paper focuses on infrastructural barriers and cloud computing; not only focusing on bandwidth, but also the entire issue of service offering. Services offered via cloud computing solutions will minimize the SMEs investment in own hardware (HW), software (SW) and maintenance. The focus is also the upgrade to a superior infrastructure that provides the platform for efficient cloud computing, for e-commerce, and beyond.

A Collision Alleviation Scheme for IEEE 802.11p VANETs

Abstract: IEEE 802.11p protocol, also known as Wireless Access for the Vehicular Environment provides dedicated short range communication for future Vehicular Ad Hoc Networks (VANETs). According to the IEEE 802.11p standard, the highest priority traffic transmission often suffers from the consecutive collisions in bursty arrival or congested scenarios because of the naive pre-assumption of a low level of congestion in the system, and thus results in emergent messages delayed. In this paper, we propose a simple, but yet well performing collision alleviation scheme to alleviate intensive collisions between highest priority access categories which usually used to schedule emergency message since safety is the most critical and promising issue in VANET. In addition to theoretical analysis, simulations are conducted to evaluate its performance. The simulation results show that the proposed scheme can not only increase the achievable channel throughput of the legacy protocol at most 15%, but also reduce the average packet access delay of the legacy protocol at least 5% and the packet collision probability at most 60% in congested VANET environments.

IP Flow Mobility in PMIPv6 Based Networks: Solution Design and Experimental Evaluation

Abstract: The ability of offloading selected IP data traffic from 3G to WLAN access networks is considered a key feature in the upcoming 3GPP specifications, being the main goal to alleviate data congestion in cellular networks while delivering a positive user experience. Lately, the 3GPP has adopted solutions that enable mobility of IP-based wireless devices relocating mobility functions from the terminal to the network. To this end, the IETF has standardized Proxy Mobile IPv6 (PMIPv6), a protocol capable to hide often complex mobility procedures from the mobile devices. This paper, in line with the mentioned offload requirement, further extends PMIPv6 to support dynamic IP flow mobility management across access wireless networks according to operator policies. Considering energy consumption as a critical aspect for hand-held devices and smart-phones, we assess the feasibility of the proposed solution and provide an experimental analysis showing the cost (in terms of energy consumption) of simultaneous packet transmission/reception using multiple network interfaces. The end-to-end system design has been implemented and validated by means of an experimental network setup.

Uncertainty Management in Context-Aware Applications: Increasing Usability and User Trust

Abstract: Uncertainty in context-aware computing is mainly a consequence of the complexity of context acquisition mechanisms and context processing. The presence of uncertainty may harm the users' confidence in the application, rendering it useless. This paper describes a three-phase strategy to manage uncertainty by identifying its possible sources, representing uncertain information, and determining how to proceed, once uncertain context is detected. We conducted an experiment to assess the impact and utility of uncertainty management in a location-aware museum guide that incorporated the approach proposed. The impact was measured by comparing the number of erroneous location estimations and the number of interactions performed by users. A survey was used to measure user friendliness, the utility of the application and user trust among 118 museum visitors who participated in the experiment. Results suggest that uncertainty management helps improve the accuracy of context estimates and the user's perception on the reliability of the application.

Mobile IP-Based Protocol for Wireless Personal Area Networks in Critical Environments

Abstract: Low-power Wireless Personal Area Networks (LoWPANs) are still in their early stage of development, but the range of conceivable usage scenarios and applications is tremendous. That range is extended by its inclusion in Internet with IPv6 Low-Power Personal Area Networks (6LoWPANs). This makes it obvious that multi-technology topologies, security and mobility support will be prevalent in 6LoWPAN. Mobility based communication increases the connectivity, and allows extending and adapting LoWPANs to changes in their location and environment infrastructure. However, the required mobility is heavily dependent on the individual service scenario and the LoWPAN architecture. In this context, an optimized solution is proposed for critical applications, such as military, fire rescue or healthcare, where people need to frequently change their position. Our scenario is health monitoring in an oil refinery where many obstacles have been found to the effective use of LoWPANs in these scenarios, mainly due to transmission medium features i.e. high losses, high latency and low reliability. Therefore, it is very difficult to provide continuous health monitoring with such stringent requirements on mobility. In this paper, a paradigm is proposed for mobility over 6LoWPAN for critical environments. On the one hand the intra-mobility is supported by GinMAC, which is an extension of IEEE 802.15.4 to support a topology control algorithm, which offers intra-mobility transparently, and Movement Direction Determination (MDD) of the Mobile Node (MN). On the other hand, the inter-mobility is based on pre-set-up of the network parameters in the visited networks, such as Care of Address and channel, to reach a fast and smooth handoff. Pre-set-up is reached since MDD allows discovering the next 6LoWPAN network towards which MN is moving. The proposed approach has been simulated, prototyped, evaluated, and is being studied in a scenario of wearable physiological monitoring in hazardous industrial areas, specifically oil refineries, in the scope of the GinSeng European project.

Weighted Steiner Connected Dominating Set and its Application to Multicast Routing in Wireless MANETs

Abstract: In this paper, we first propose three centralized learning automata-based heuristic algorithms for approximating a near optimal solution to the minimum weight Steiner connected dominating set (WSCDS) problem. Finding the Steiner connected dominating set of the network graph is a promising approach for multicast routing in wireless ad-hoc networks. Therefore, we present a distributed implementation of the last approximation algorithm proposed in this paper (Algorithm III) for multicast routing in wireless mobile ad-hoc networks. The proposed WSCDS algorithms are compared with the well-known existing algorithms and the obtained results show that Algorithm III outperforms the others both in terms of the dominating set size and running time. Our simulation experiments also show the superiority of the proposed multicast routing algorithm over the best previous methods in terms of the packet delivery ratio, multicast route lifetime, and end-to-end delay.