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Location Based Notification (LBN) aims to alert the users in a target area with the information of interest to them. With a wide range of applications, LBN has been gaining more and more attraction among wireless users and service providers. The mainstream centralized solution based on cellular networks may incur high service cost. In this paper, we present an innovative scheme called Phoenix, which does not rely on any infrastructure, to implement for location based notification service. In our design, devices (users) across the target area form a dynamic peer-to-peer network, where a user can be a message source, a message carrier, or a message subscriber. When a user meets the message carrier, the user can get a copy of the message. Phoenix keeps messages of interest being circulated in the target area, hence users are being notified. To achieve desired notification performance, Phoenix adaptively controls when a user should take the carrier role and help disseminating a message in order to keep the message ``alive", given the fact that message carriers may leave the target area and drop the message. Extensive simulations have been conducted to show the efficacy of Phoenix notification system.

It has been shown that sink mobility provides an energy-efficient approach to data delivery in wireless sensor networks (WSNs). Most of the approaches targeted to WSNs with mobile sinks (MSs) addressed the problem of data delivery where only a few messages are reported during a long time frame. However, transmitting streaming data is becoming relevant in WSNs, as more and more multimedia sensor nodes - equipped with image, audio, and video capabilities - are being used to characterize the sensing environment. In this scenario, a sequence of messages propagates into the network, hence the problem of finding an effective routing path for delivering data to MSs becomes even more challenging, since the communication overhead for reaching the MS might also be significant. In this paper, we present an energy-efficient streaming data delivery (SDD) protocol for cluster-based WSNs with MSs. Different from existing works, we focus on the mobility support for the delivery of streaming data in hierarchical WSNs. By introducing a cross-cluster handover mechanism and a path redirection scheme, SDD maintains the end-to-end connectivity between the source and the MS, while avoiding the constant transmission of the MS location as it moves across multiple clusters. We evaluate the performance of the proposed SDD protocol, and compare it with a hierarchical cluster-based data dissemination protocol. Simulation results demonstrate its effectiveness, in terms of both end-to-end delivery delay and energy-efficiency.

This paper presents a cross-platform solution of smartphone-based mobile sink for wireless sensor networks, named uSink. With a cross-platform SD card, named uSD card, any smartphone with SD interface can be empowered with the capability to communicate with wireless sensor nodes. Furthermore, a middleware on mobile phone, named uSinkWare, is also designed to provide a typical mobile sink's functionalities, including sensor detection, topology monitoring, routing, sensor data collection and sensor control, etc. Thanks to Qt, uSinkWare can also work on many popular mobile platforms, such as Symbian, Maemo, Windows mobile and embedded Linux. uSink has been implemented, and its performance has been verified by experiments. The experiment results show that current high-end smartphones have enough capabilities to work as mobile sinks, and uSink can be regarded as an attempt on this aspect.

Usually, sensor data needs to be disseminated from the source sensors to data collectors (e.g., sink nodes), making those spatially distributed sensor data available for applications to access. The widespread and ubiquitous nature of mobile devices, e.g., PDAs and cell phones around the world, makes them attractive to be used as mobile data collectors (MDCs) to collect and deliver the sensor data. The goal of this work is to design a dissemination protocol that leads to efficient data delivery from the source sensors to ubiquitous MDCs. We propose the Wait-Focus-Spray (WFS) scheme for wireless sensor networks with ubiquitous MDCs. The main objective of WFS is to balance the data delivery latency and transmission overhead when considering the existence of ubiquitous MDCs. In WFS, we also propose a corresponding mechanism-probabilistic scattered binary spraying (PSBS), to reduce the spatial redundancy when spraying data copies, which can increase the probability of meeting a MDC. Through extensive simulations, we demonstrate that our WFS scheme reduces the transmission cost per message while provides comparable delivery delay compared with the existing work.

In the application layer of ad hoc network, a location based video source switching algorithm is designed, by which mobile users can get the interested video content from other mobile devices. The algorithm is applied in a gymnasium scenario, for a point to point multi-hop video sharing application in ad hoc network that is self-organized by the mobile terminals. A prototype is implemented for this scenario. We demonstrate the feasibility of the proposed algorithm and analyze the performance of end-to-end packet loss rate and RTT (Round-trip time) in 1-hop and 2-hop cases.

Recent developments of information technologies are leading the advent of mobile device oriented context-aware applications??which means using context to realize some novel applications on mobile devices. The context-aware application needs a framework for context information management. In this paper, we propose a mobile device oriented framework for context information management to solve the problems on context shortage and communication inefficiency. It consists of four main functional components: data collector, context processor, context manager and local context consumer. By using the framework, data collector collects data from internal and external sensors, then the context processor and manager extract and manage context, finally the local context consumer develops context-aware applications and provides appropriate services to the mobile users. The propose framework realizes real time application with quick data access, power efficiency, personal privacy protection, data fusion of internal and external sensors and simplicity in usage. In order to show the feasibility of the proposed system, an example scenario is given, which is applied to a context-diary system.

In this paper, meeting position aware routing (MPAR) is proposed for query-based mobile enabled wireless sensor network (mWSN). We consider mWSNs with dense sensor nodes deployed in the sensing field. A mobile sink (MS) moving through the sensing field with random speed queries a specific area or a point of interest for information from physical world. Queried data over a area is aggregated to a source node and delivered to the mobile sink via multi-hop communication. The feature of MPAR is that the mWSNs can predict the position of the mobile sink at the time it meets the data packet. The queried data packet is delivered towards this predicted position from the source node during the propagation. We compared MPAR with the existing routing protocol for the similar sce- narios. Analysis was conducted to discover the conditions under which MPAR demonstrates the optimal performance. Extensive simulations were also conducted to evaluate the performance of the routing mechanism as well as to compare it with existing method. Evaluation results show that MPAR outperforms the existing mechanism in that it provides less end-to-end delivery latency, and consequently reduces the energy consumption. The robustness to variation of MS velocity is also improved. Index Terms—Wireless sensor networks; query-based data collection; mobile sink

Location service provides position of mobile destination to source node so that position based routing can be applied. Several quorum-based location services have been proposed. These location service protocols suffer from complex structure with high overhead, or host location foreknowledge, and difficulty in quorum construction. To overcome those deficiencies, we propose a novel quorum-based location service. In the proposed scheme, location databases are stored in the network nodes themselves, which form a self-organizing virtual backbone network. Quorum system is constructed on the virtual backbone network in conformity to irregular grid rule. Every mobile node will notify its location update information to irregular grid quorum system so that other hosts can obtain the mobile node location through irregular grid quorum system. The simulation results show that our proposed location service leads to high success rate, appropriate quorum size and good load.

Location service provides position of mobile destination to source node so that position based routing can be applied. Several quorum-based location services have been proposed. These location service protocols suffer from complex structure with high overhead, or host location foreknowledge, and difficulty in quorum construction. To overcome those deficiencies, we propose a novel quorum-based location service. In the proposed scheme, location databases are stored in the network nodes themselves, which form a self-organizing virtual backbone network. Quorum system is constructed on the virtual backbone network in conformity to irregular grid rule. Every mobile node will notify its location update information to irregular grid quorum system so that other hosts can obtain the mobile node location through irregular grid quorum system. The simulation results show that our proposed location service leads to high success rate, appropriate quorum size and good load.

We describe a framework for wireless sensor network (WSN) based mobile mashup applications. The framework consists of four functional components: WSN, mobile gateway, context management platform, and mashup server. The WSN deployed in the application domain senses the physical phenomena and the human-environment interaction and expresses them in sensor readings. The mobile phone is used as the gateway to the WSN, which can directly communicate with the sensor nodes and collect the user related sensor data. On the mobile phone, the raw sensor data is preprocessed and the user-centric contexts are extracted. The context management platform stores all contexts according to the predefined context ontology, detects the inconsistent information, deduces the high level knowledge using heuristic rules and provides web service application programming interfaces (APIs) to mashup server. The mashup server integrates the context information obtained from the context management platform with the information from other mashup data sources, and provides services to users through mobile phone. The proposed framework can be used in exhibition center, shopping mall, smart office/home, and many other scenarios.

Utilizing mobile devices such as PDAs, cell phones to collect and deliver sensor data is considered as a promising application in future ubiquitous computing environment. In such application scenarios, the human factor is becoming increasingly important. In this paper, we propose a group-level incentive scheme targeted for encouraging mobile users to collect sensor data. Such idea of widening the scope of incentive from device-level to group-level is inspired by the incentive scheme of blood donation in real life. Mobile users earn credits by collecting and delivering sensor data with their mobile devices and they may consume the credits to access the services provided by wireless sensor networks applications. The main idea of the group-level incentive scheme is to group mobile users into social groups and share credits so that credits earned by one user can be consumed by another user in the same group. Through theoretical analysis and simulation we illustrate the potential of the proposed solution.

With the increasing demand for realtime multicast service in mobile wireless sensor networks (mWSN), it is needed to provide new Rendezvous Point (RP) Selection Schemes for mWSN. Due to the arbitrary node mobility in mWSN, where mobile nodes usually go beyond someone RP’s coverage, multicast algorithm requires not only end-to-end constrained latency, but also short RP-switch time and low routing cost to guarantee the uninterrupted real time data streaming. The paper proposes a quick looking-up RP scheme for multicast algorithm based on quorum system. Results obtained through simulations demonstrate that the algorithm reduces RP-switch time and average routing cost.

In the paper, a new range-boundary aware mobility-assisted localization(RAML) scheme is presented to make mobile sink identify the location of sensor nodes which are deployed in a random mode within a certain geographical area. Not like other localization techniques, the presented localization scheme works without any additional hardware and achieves better efficiency through broadcasting special beacon messages for single hop acknowledgement. Sensor node location is calculated after two specific time-stamps are obtained, one time-stamp once the sink just enters into the communication range of the sensor node and another one once it leaves. We present detailed description of RAML as well as its implementation approach in real-world and simulation environments, respectively. Simulation in ns-2 is conducted to verify the efficiency and correctness of RAML.

The combined and separated research advancement in the fields of sensing, communication, and computing have driven the research efforts in wireless sensor networks (WSN) in recent years. According to the traditional definition of WSNs, a dense, static, and prohibitively expensive sensor deployment is implicitly required, which has limited the feasibility of WSNs in non-military approaches. Aside from stationary sensor and sink deployment, the introduction of mobility of mobile terminals into WSNs can be leveraged to alleviate the burden of certain static sinks in order for efficient information repository, dissemination and sharing. In this paper, an architecture of multi-radio enabled mobile wireless sensor network (MEMOSEN) has been introduced, which has taken the heterogeneity and mobility of sensors and sinks into account. The capacity gain due to mobility in MEMOSEN has been addressed, and the design challenges and potential applications of MEMOSEN have been analyzed as well.