Near Field Communication (NFC) is a wireless communication technology using 13.56 MHz to support 2-way communications between two devices within ~10 cm. Such a short communication range may be considered as a shortcoming, but at the same time, this enables a secure data transfer within the connectivity region when compared to Bluetooth Low Energy (BLE) or Wi-Fi. Accordingly, NFC can be optionally utilized when secure data are transmitted in various services and applications focusing on ID validation. This demo presents a proof-of-concept for an alternative packet transmission method for achieving secure data exchange based on IP-over-NFC technology. For realizing this, there are a number of technical challenges. Utmost, the current NFC Linux kernel driver requires updates for supporting network-layer functionalities. Using such implementations, this demo demonstrates the procedures of transmitting secure data using NFC, while normal packet transmissions occur over WiFi simultaneously.

Differential equations play a noticeable role in engineering, physics, economics, and other disciplines. In this paper, a general approach is suggested to solve a variety of linear and nonlinear ordinary differential equations (ODEs). With the aid of certain fundamental concepts of mathematics, Fourier series expansion and metaheuristic optimization methods, ODEs can be represented as an optimization problem. The aim is to minimize the weighted residual function (error function) of the ODEs. The boundary and initial values of ODEs are considered as constraints for the optimization model. Generational distance metric is used for evaluation and assessment of approximate solutions versus exact solutions. Two ODEs and one mechanical problem are approximately solved and compared with their exact solutions. The optimization task is carried out using different optimizers including the particle swarm optimization and the water cycle algorithm. The optimization results obtained show that the metaheuristic algorithms can be successfully applied for approximate solving of different types of ODEs.

Many dissemination protocols on the mobility support in wireless sensor networks have been designed based on the assumption that the movement trace of sinks is random. However, the mobility of the sinks in many applications, for example, the movement traces of a soldier on operation in a battle field or a firelight on rescue operation in the disaster area, can be determined in advance since they move in accordance with the decided operation or the drill regulation to perform their task. In this paper, we propose a Predictable Mobility-based Data Dissemination protocol (PMDD) that enables data to directly route from source nodes to moving sinks by taking into consideration predictable movement behavior of the sinks. We also compare the performance of the PMDD with those of other dissemination protocols with random movement behavior of the sinks, and show the superiority of the PMDD based on network lifetime, data delivery ratio, and delay latency.

Typical wireless sensor networks consist of sensor nodes and base-stations (sinks). The sensors, sinks, and user nodes can orthogonally provide their own mobility environments. The existing studies take only sensor mobility, sink mobility, and event mobility into account. Inquirer mobility, however, can be possibly suggested as one of the mobility models. An inquirer is one of the existing entity for sensor networks as a user. Inquirer mobility and routing mechanism to support it are proposed in this paper. For that, possible mobility environment and characteristics are also analyzed. At the end of this paper, excellence of the proposed routing model is proved through simulation results.

Sensor networks are composed of a great number of sensor nodes. Since all sensor nodes are energy-restricted and hard to recharge, it is very important. However, the energy consumption may significantly increase if mobile sources or sinks exist in sensor networks. The reason is that the routing information for mobile sources and sinks needs to be update frequently for efficient data delivery. The routing algorithm supporting mobile sinks should consider not only continuous data delivery but also the energy consumption of sensor nodes. However, most of the existing research e.g. Fan Ye, et al. (Set. 2002), Zehua Zhou, et al., (Jun 2006) focuses on even energy consumption while the mobility of sinks and sources is rarely consider. In this paper, we propose an efficient routing protocol with multiple virtual grids to reduce energy consumption and improve packets delivery efficiency. Simulation results show that our algorithm can guarantee high data delivery ratio and lower average delivery delay, while consuming lower energy than existing routing protocols in sensor networks.

Fast Mobile IPv6 has been proposed to reduce latency and packet loss inherent to the handover process. However the previous research did not consider the packet loss according to the tunnel management for Fast Mobile IPv6. In the procedure of binding updates and fast binding updates, a mobile node has to establish new tunnels after receiving binding acknowledgement messages. While completing the tunnel creation and routing update, the mobile node can not handle packets incoming and outgoing through the new tunnels. This drawback causes packet loss of impeding the seamless handover. To reduce this packet loss, we have developed an effective tunnel management scheme called Dual Mode Tunneling (DMT). It employs decapsulation-only tunnels before using typical tunnels which can do an encapsulation and decapsulation. Through implementation and experimental study for vertical handover between 3G long term evolution and wireless local area network, we have evaluated the performance of the proposed scheme.

Void areas (holes) as an inevitable phenomenon exist in geographic routing of wireless sensor networks, because the unpredictable and harsh nature application environment or uneven energy consumption. Most of the existing schemes for the issue tend to construct a static detour path to bypass a hole. The static detour path may lead to uneven energy consumption of the nodes on the perimeter of the hole; thus it may enlarge the hole. At the same time, traffic would concentrate on the peripheral node of the hole; thus the nodes on the perimeter of the hole tend to be depleted quickly. In previous work, we have proposed a hole geometric model to reduce the energy consumption and packet collisions of the nodes on the hole boundary. This scheme, however, still has the static detour path problem. Therefore, we extend the previous work by constructing a dynamic detour path hole geometric model for wireless sensor networks in this paper. The location of hole detour anchor is dynamically shifted according to Gaussian function, just generating dynamic hole detour paths.

Geographic routing has been addressed in many literatures of ad hoc sensor networks due to its efficiency and scalability. Void areas (holes) bring geographic routing several problems such as excessive energy consumption and data congestion of hole boundary nodes. Holes are hardly avoided in wireless sensor networks because of various actual geographical environments, e.g., puddles, buildings or obstacles, or uneven energy consumption, even physical destruction. To bypass holes, most existing geographic routing protocols tend to route data packets along the boundaries of holes by perimeter routing scheme. This scheme consumes more energy of the nodes on the boundaries of holes, thus possibly enlarging the holes, we call this hole diffusion problem. In this paper, we propose anchor node based virtual modeling of holes in wireless sensor networks to solve the hole problems faced by geographic routing in wireless sensor networks. Simulation results show that the proposed protocol is superior to other protocols in terms of packet deliver ratio, control overhead, average delivery delay, and energy consumption.

Mobile IPv6 (MIPv6) used to support IP mobility in heterogeneous network such as the universal mobile telecommunications system (or long term evolution system) and 802.11 wireless local area networks (WLANs). But MIPv6 has well-known packet loss during movement detection and binding update, but it has another packet loss while creating new tunnel and updating routing path. That is, when the home agent sends a binding acknowledgement (BA) message to mobile node after receiving a binding update (BU) message, the new tunneled packets are also sent to MN with the BA message. After receiving the BA message, the MN creates new tunnel and modifies routing information. But while completing these procedures, the MN can not handle new tunneled packets incoming together the BA message. To solve this problem, this paper proposes the dual tunneling mechanism(DTM) to reduce the additional loss using the reception- only tunnel. In this paper, we analyze the packet delay time in overlay and non-overlay network in case of general mobile IPv6 and DTM, and observe the handover experimental result for the 3G LTE-WLAN network.

Geographic routing is attractive in wireless sensor networks especially for scalability, as it is possible to scale the network size without increasing the signaling overhead, because routing decisions are inherently localized. Geographic routing requires the sources nodes to be aware of the location of the sinks. Most of existing geographic routing protocols merely assume that the sources can get the location of sinks by some location service. How can source nodes obtain the location of sinks is not addressed in detail. In this paper, we propose an anchor node based sink location dissemination scheme for geographic routing in wireless sensor networks. In this scheme, a source node and a sink node send sink location announcement and query messages along two paths respectively by geographic routing. The node located on the crossing point of the two paths informs the source about the sink location. The challenge of this paper is that how to guarantee these two paths having at least one crossing point in any irregular profile of sensor network. Simulation results show that our protocol is significantly superior to other protocols in terms of energy consumption and control overhead.

In wireless sensor networks, a communication model that separate a sink collecting information from sensor nodes and a user using it has been proposed. In the model, a mobile user appoints a neighborhood sensor node as a dynamic sink, and the dynamic sink collects data from all sensor nodes and forwards the aggregated data to the mobile user. In this paper, we expand the model for single mobile user to support multiple mobile users. A core of the novel model is mapping between single dynamic sink and multiple mobile users. Namely, multiple mobile users appoint a dynamic sink and the sink collect information from all sensor nodes and forward them to the multiple mobile users. To design effectively the novel model, two issues should be solved. First, the multiple mobile users without any mutual communication channel should efficiently choose and appoint only one dynamic sink. Second, the single dynamic sink should forward the collected information to the multiple mobile users. This paper proposes a solution for those issues. The solution consists of three schemes: 1) data collection scheme, 2) tree-based multicast scheme, and 3) user mobility support scheme. The data collection scheme is to solve the first issue and the tree-based multicast scheme is to solve the second issue. Also, the user mobility support scheme is to guarantee data forwarding to mobile users.

Geographic routing has been considered as an efficient, simple, and scalable routing protocol for wireless sensor networks since it exploits pure location information instead of global topology information to route data packets. Geographic routing requires the sources nodes to be aware of the location of the sinks. How can source nodes get sinks locations with low overhead is a difficult issue in wireless sensor networks. In this paper, we propose a Sink Location Service for geographic routing in wireless Sensor Networks. In this scheme, a source node and a sink node send sink location announcement and query messages along two paths respectively by geographic routing. The node located on the crossing point of the two paths informs the source about the sink location. Then the source can send data packet to the sink by geographic routing. How to guarantee that these two paths have at least one crossing point in any irregular profile of sensor network is the challenge of this paper. Simulation results show that our protocol is significantly superior to other protocols in terms of energy consumption and control overhead.

Void areas (holes) are hardly avoided in wireless sensor networks because of various actual geographical environments, e.g., puddles, buildings or obstacles, or uneven energy consumption. To bypass holes, most existing geographic routing protocols tend to route data packets along the boundaries of holes by perimeter routing scheme. Such a scheme depletes the energy of nodes on the boundary of holes faster than others and is likely to result in earlier deaths, thus enlarging the hole sizes, a phenomenon we call the hole diffusion problem. Routing along the hole boundary may also lead to increased collisions especially if multiple data streams try to bypass a hole simultaneously. In this paper, we propose virtual circle based geometric modeling of holes for geographic routing to address these problems in wireless sensor networks. Our proposed algorithm avoids routing on the hole perimeter by selecting appropriate intermediate anchor nodes (close to the hole boundary) and routing via this anchor node. We show by simulation that our proposed algorithm provides significant savings in energy consumption, shorter routing delays, higher packet delivery ratio, all with comparable control overhead as compared with state-of-the-art techniques.

Wireless sensor networks traditionally consist of sensors perceiving data and sinks gathering the data. In addition, users receive required information from the sinks via infrastructure networks. The users, however, should receive the information from the sinks through multi hop communications of disseminated sensor nodes if such users move into the sensor networks without infrastructure networks. Unlikely, the previous works only considered mobility of sinks, which function users. Nevertheless, it is difficult for such approaches to mobility to exploit the existing data-centric routing algorithms and also for the mobile sinks to function as gateways to connect with infrastructure. To improve the shortcomings, we suggest a novel viewpoint of mobility for wireless sensor networks and propose a solution to support the mobility with multiple static sinks in this paper. The multiple static sinks, which are connected with each other via infrastructure, provide high throughput and low latency. Furthermore, they improve hotspot problems and prolong network lifetime. The proposed mechanism finally is evaluated by simulation results about throughput, latency, and network lifetime.

Wireless sensor networks are composed of a great deal of energy restricted sensor nodes and targets (events) at long- term usage such as environment monitoring. The failure of sensor nodes caused by energy exhaustion or physical destruction may lead to the reduction of sensor areas. In the wireless sensor networks, the nodes located on the edge of holes are relatively weaker than other sensor nodes since the geographic routing scheme tends to route data packets along the edge of holes by the right hand rule. It results in more energy consumption or even exhausts the energy of the hole edge nodes, so it may enlarge the holes. We call this, aholediffusionproblem. The right hand rule may also lead to data collisions on the hole edge nodes if multiple communication sessions need to bypass a hole simultaneously. In this paper, we propose hole modeling to handle the hole problem in wireless sensor networks. Our hole modeling can efficiently prevent the hole diffusion, avoid the local minimum faced by geographic routing protocols, and reduce data collisions on the hole edge nodes. Simulation results present our protocol is superior to the previous works in terms of control overhead, average delivery delay and energy consumption.

Void areas (holes) are hardly avoided in sensor networks either because of various actual geographical environments, e.g., puddles, buildings or obstacles, or uneven energy consumption. To bypass holes, most existing geographic routing protocols tend to route data packets along the boundaries of holes. Generally, a data packet will be either forwarded along a hole boundary by the right hand rule or pushed back to find another route to its destination when the data packet encounters the hole boundary. The right hand rule, on one hand, consumes more of the nodes' energy on the boundaries of holes, thus possibly enlarging the holes; on the other hand, it may incur data collisions if multiple communication sessions share the same boundaries of holes simultaneously. In this paper, we will propose a hole geometric modeling to solve hole problem in wireless sensor networks. Our hole geometric modeling has two goals: one is to prevent data packets from traveling along the boundaries of holes; the other is to avoid the problem of local minimum phenomenon. By achieving the first goal we can not only reduce the energy consumption of the nodes on the boundaries of holes, thus preventing holes' diffusion, but also reduce the data collisions in the nodes on the boundaries of holes. The second goal can reduce the packets rerouting overhead.

Overlay multicast protocols in mobile ad hoc networks (MANET) have advantages that are low overhead and robustness in dynamic network topology by using the unicast routing protocol between group members. However, overlay data paths in overlay multicast can remain static even though the underlying physical topology is changing. Overlay multicast may lead to sub-optimal overlay data paths, since the communicating group members are not aware of the underlying physical topology. Therefore, overlay multicast protocols requires periodic control messages for the overlay data path management in dynamic environment. In this paper, we propose an efficient overlay multicast protocol (EOMP) using unicast routing information. Multicast state information of each group member in EOMP is created by its unicast routing table. Therefore, multicast data packets between group members are delivered through the overall optimal paths in physical networks. Meanwhile, the overlay data path in EOMP can be managed without periodic control messages in the dynamic environment. Finally, we evaluate EOMP performance with other multicast protocols proposed for ad hoc networks. Simulations show enhanced results of proposed protocols

Typical sensor networks consist of a user, a sink, and a number of sensor nodes. The traditional communication architecture usually assumes that there is a legacy networks between a user and a sink. However, in many actual applications users like firefighters and soldiers move around sensor fields and they may not have any direct communication through legacy networks. In other words, a sensor network is the only communication channel between a user and a sink in a practical sensor field. Thus, it is essential to deliberate a novel architecture for the user mobility issue. In this paper, we present a novel communication architecture where a user operates around an infrastructureless sensor field. We, then, propose a new networking model to support user mobility on the novel architecture, named dynamic sink model. In the model a sink is temporarily selected among generic sensor nodes by a user when the user wants to get information from a sensor network. The selected sink gathers data from sensor nodes for interested tasks and propagates collected information to the user via the sensor network. We evaluate and analyze performance of the proposed dynamic sink model on the novel architecture with regard to efficiency of energy consumption, average delay, and delivery ratio, compared with the common static sink model on typical communication architecture

Stable multicast data delivery structure contributes high data delivery ratio and low control overhead in Mobile Ad Hoc Networks (MANETs). Due to dynamic topology of MANETs, to construct a stable multicast data delivery structure becomes a challenge in ad hoc environment. In this paper, we propose a stable overlay multicast protocol for MANETs based on modified Delayed Forwarding mechanism. In this protocol, each member node precalculates its stability according to remaining battery and local mobility of itself. A source rooted overlay multicast tree is created if source has to send data packets. The overlay creation follows the stability of each member node. By using modified Delayed Forwarding mechanism, a member node with relatively high stability will have highly populated subtrees, by this way to improve multicast routing stability. Data packets are transmitted via IP-in-IP tunnels between member nodes in the overlay tree.

A characteristic of mobile ad hoc networks, mobility leads to frequently update multicast routing information based on network multicasting. For the reason, comparatively lots of control signaling messages are generated, so bandwidth of wireless media and limited battery power of mobile nodes are inefficiently consumed. To improve the shortcomings, overlay multicast protocols on application layer has been proposed; however, some of them have another shortcoming which is that the number of unnecessary data forwarding among multicast members increases. Additionally, they hardly support network scalability. Thus, this paper proposes an implicit cluster-based overlay multicast protocol exploiting tree division (ICOM-TD) for mobile ad hoc networks to improve their shortcomings. Finally, we evaluate performance of ICOM-TD through numerical analysis about complexity of multicast routing and simulation in comparison with existing multicast mechanisms for ad hoc networks on end-to-end time delay, packet overhead, and delivery ratio.

Typical sensor networks consist of users, sinks, and a number of sensor nodes. The traditional architecture usually assumes that there is a legacy network between users and sinks. However, practical users like firefighters and soldiers move around sensor fields and they might not have any direct communication through legacy networks. In other words, sensor networks are the only communication channel between users and sinks in practical sensor fields. Now there are no researches with respect to architecture to support the user mobility. Thus it is necessary to deliberate a new architecture for such the issue. In this paper, a novel communication architecture was presented where a user operates around an infrastructureless sensor field. A new networking model was then proposed, named dynamic sink model, to support user mobility on the novel architecture. In the model a sink is temporarily selected among generic sensor nodes by a user when the user wants to get information from a sensor network. The chosen sink gathers data from sensor nodes for interested tasks and propagates collected information to the user via the sensor network. The performance of the dynamic sink model on the novel architecture was evaluated and explored with regard to average delay, delivery ratio, and network lifetime compared with the common static sink network model on typical communication architecture.

The previous tree-based and mesh-based multicasting in mobile ad hoc networks need to be improved because of their shortcomings of the mechanisms. One of them is lots of signaling overheads to modify multicast trees due to dynamic topology, and the other is inefficiently exploiting wireless network resources for delicately set paths. For the reason, overlay multicast mechanisms in mobile ad hoc networks are proposed to improve such shortcomings, yet they also result in the other problems, which are network scalability and inefficient transmission among dense multicast members. In this paper, An overlay multicast mechanism based on single-hop clustering and tree division (OMCD) in mobile ad hoc networks is proposed to improve all the problems. The OMCD exploits single-hop clusters to manage dense multicast members and to reduce overheads by broadcasting. The clusters are created and delegated by cluster leaders, based on location information. Also, multicast sources in OMCD deliver multicast data to only the leaders through overlay multicast tree (OMT) but not all multicast members. Finally, performance of the proposed OMCD is also evaluated by analysis and simulation in the end of this paper