Multi-hop Sensor Networks Research Articles

A ZigBee-based elderly health monitoring system: design and implementation

Internet of Things and its associated innovative technologies such as ZigBee, wireless sensor network, radio frequency identification, smart technologies (robotics), distributed databases and energy saving technologies have huge potentials in remote healthcare monitoring system and medical services to augment aging citizens' living style, safety, healthcare services and also reshape the future of our healthcare environments. This paper explores the intended system to achieve elderly health monitoring system. The designed system obtains, transmits, stores and analyses the elderly physiological conditions for healthcare providers exactly in real time intrusive or non-intrusively through tiny human wearable multi-hop sensor network. Hence collaborative remote healthcare services to identify common or critical health problems, sickness symptoms and remote diagnosis. It also provides supportive healthcare service with indigenous assimilation and booming out efficient service to prevent chronic disease and edifice a robust elderly healthcare monitoring system with appraisal, inspiration and assurance, etc. It guarantees the elderly life of integrated care and comprehensive remote health information management. The proposed system primarily depends on Internet of Things, ZigBee, wireless sensor network, body sensors, web applications and databases.

Scheduling multi-channel and multi-timeslot in time constrained wireless sensor networks via simulated annealing and particle swarm optimization

Timely communication in wireless multihop sensor networks requires high throughput and low delay, which can be achieved by exploiting multiple channels and time slots. Efficient scheduling becomes indispensable if multiple channels and time slots are utilized. Optimum scheduling of multiple channels and time slots in multihop networks is an NP-complete problem. We apply metaheuristic approaches to solve the scheduling problem because of the fact that not only the global solution but near-optimal solutions can satisfy a given end-to-end delay bound. We adopt simulated annealing (SA) and particle swarm optimization (PSO) to schedule the resources. Different measures and stopping conditions are explored to validate the feasibility of scheduling via SA and PSO, and to compare the performance of the two metaheuristics in satisfying the desired end-to-end delay. Although the purpose of this article is to compare SA and PSO, the simulation results demonstrate that PSO-based scheduling outperforms SA-based scheduling in terms of end-to-end delay.

멀티홉 센서 네트워크에서 에너지 상황을 고려한 시스템 수명 최대화 알고리즘

This paper addresses the system lifetime maximization algorithm in multi-hop sensor network system. A multi-hop sensor network consists of many battery-driven sensor nodes that collaborate with each other to gather, process, and communicate information using wireless communications. As sensor-driven applications become increasingly integrated into our lives, we propose a energy-aware scheme where each sensor node transmits informative data with adaptive data rate to minimize system energy consumption. We show the optimal data rate to maximize the system lifetime in terms of remaining system energy. Furthermore, the proposed algorithm experimentally shows longer system lifetime in comparison with greedy algorithm.

A practical approach for provenance transmission in wireless sensor networks

Assessing the trustworthiness of sensor data and transmitters of this data is critical for quality assurance. Trust evaluation frameworks utilize data provenance along with the sensed data values to compute the trustworthiness of each data item. However, in a sizeable multi-hop sensor network, provenance information requires a large and variable number of bits in each packet, resulting in high energy dissipation due to the extended period of radio communication. In this paper, we design energy-efficient provenance encoding and construction schemes, which we refer to as Probabilistic Provenance Flow (PPF). Our work demonstrates the feasibility of adapting the Probabilistic Packet Marking (PPM) technique in IP traceback to wireless sensor networks. We design two bit-efficient provenance encoding schemes along with a complementary vanilla scheme. Depending on the network size and bit budget, we select the best method based on mathematical approximations and numerical analysis. We integrate PPF with provenance-based trust frameworks and investigate the trade-off between trustworthiness of data items and transmission overhead. We conduct TOSSIM simulations with realistic wireless links, and perform testbed experiments on 15–20TelosB motes to demonstrate the effectiveness of PPF. Our results show that the encoding schemes of PPF have identical performance with a low bit budget (∼32-bit), requiring 33% fewer packets and 30% less energy than PPM variants to construct provenance. With a twofold increase in bit budget, PPF with the selected encoding scheme reduces energy consumption by 46–60%.

Performance Analyses and Improvements for IEEE 802.15.4 CSMA/CA Scheme in Wireless Multihop Sensor Networks Based on HTC Algorithm

Most of analyses for the IEEE 802.15.4 Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) scheme for multi-hop wireless sensor networks (WSNs) focus on how to avoid the impacts of hidden terminal problems rather than how to derive the exact multi-hop characters. In this paper, we propose a novel analysis model to analyze and improve the behaviors of multi-hop WSNs touching upon both avoiding the impacts of hidden terminals and acquiring the exact multi-hop behaviors. At first, a novel Hidden Terminal Couple (HTC) algorithm is proposed to avoid the impacts of hidden terminals, and a parallel access scheme is proposed to dispense with taking the routing overhead into account. Along with these two strategies, the accurate statistical performance metrics of throughput and delay of unsaturated, unacknowledged IEEE 802.15.4 beacon-enabled networks for 1-hop and 2-hop scenarios are then predicted based on the models which contains n modified semi-Markov chains and one macro-Markov chain, in which nodes are assumed to locate randomly over a circle plane according to Poisson distribution. Moreover, performance comparisons between our scheme (called HTC scheme) and other multi-hop CSMA/CA schemes which involve hidden terminal avoiding are also proposed. Comprehensive NS-2 simulations demonstrate that the analysis results of these models match well the simulation results, especially for larger transmission range and relatively higher node density. Besides, the analysis and comparison results show that delay behavior of HTC is improved largely relatively to other schemes, while throughput performance is improved in some cases of more node density and larger transmission range.

Channel-Aware Tracking in Multi-Hop Wireless Sensor Networks with Quantized Measurements

A channel-aware target tracking approach is proposed for multi-hop sensor networks based on M-bit quantized measurements. For two cases where the fusion center has the knowledge of the instantaneous fading channel gains and where only the knowledge of fading channel statistics is available, particle filtering (PF)-based channel-aware tracking algorithms are developed. Furthermore, the posterior Cramer-Rao lower bounds (PCRLBs) for the tracking filters are derived. The improved tracking accuracy and robustness of the proposed approach are demonstrated through simulations.

Non-uniform distribution of multi-hop sensor networks: performance improvement and energy hole mitigation

The authors consider that packet forwarding strategies drastically affect the traffic patterns in multi-hop wireless networks such as wireless sensor networks (WSN). The converge-cast nature of the WSN traffic pattern is an imbalanced pattern, which leads to many issues including: 1- energy holes 2- high delay 3- traffic blockage. In this study, the effects of the node's density on the total delay, throughput and consumed energy of a WSN is considered. Here the authors demonstrate that under a non-uniform distribution method the WSN encounters much lesser energy holes and prolongs the network life cycle. So Zipf distribution is used and the performance metrics and lifetime of a WSN for uniform and Zipf distribution are compared. The simulation results show that a WSN with Zipf distribution works more energy efficient than a uniform density network. Also the Zipf distribution with different characterising exponent reports a trade-off between network lifetime and end-to-end delay.

EHM: a novel efficient protocol based handshaking mechanism for underwater acoustic sensor networks

Underwater Media Access Control (MAC) protocol design faces more challenges due to the unique characteristics of acoustic communication such as the long propagation delay and limited bandwidth. The long propagation delay in underwater causes the hidden terminal and spatially unfair problem. In this paper, we propose an efficient MAC protocol for multi-hop underwater acoustic sensor networks, which we shall call the EHM--Efficient Handshaking Mechanism. It is a handshaking-based protocol that addresses the hidden terminal and spatially unfair problem, and the EHM protocol can improve the channel utilization by allowing a node to receive data packets from multiple potential senders simultaneously. This method can reduce the relative proportion of time spent on control packets. The performance of the proposed protocol is evaluated via simulations. Experiment results show that the EHM protocol outperforms in channel utilization, fairness of transmission and end-to-end packets delay.

Design of Mine Gas Remote Monitoring System Based on TinyOS

Monitoring system design of mine gas Monitoring System were designed according to the traditional lacked of the real-time and early warning functions and so on problems. A multi-hop sensor network based on TinyOS is designed. The system is based on hierarchical network architecture. The software design principle based on TinyOS is introduced, which can realize the multi-hop communication. A simple Ant colony algorithm is designed in this sensor network to improve the network lifetime. According to simulation results and Test Research, this system can efficiently realize the multi-hop data communication and reliable.

Lightweight Data Synchronization Scheme in Heterogeneous Sensor Networks

Data synchronization is critical for many sensor network operations including collaborative sensing, sensor scheduling and data fusion. Currently, large number of synchronization schemes have been proposed for the sensor network under the assumption that sensors work with the same network structure, network protocol and radio module. These techniques cannot survive in the heterogeneous sensor networks with the development of internet of things. In this paper, we propose a lightweight data synchronization scheme with low power which consists of two phases: first, we propose a heterogeneous clock synchronization algorithm based on the gateway which can synchronize the multi-hop sensor network with the TCP/IP network immediately without introducing amount of communication overhead; then, we also propose a synchronization control scheme in the gateway and we can balance the synchronization requirements through the adaptive buffer management. We implement the proposed scheme in real heterogeneous sensor network platform, and the experiment results show that our scheme can achieve high synchronization accuracy.

Efficient Scheduling for Periodic Aggregation Queries in Multihop Sensor Networks

In this paper, we study periodic query scheduling for data aggregation with minimum delay under various wireless interference models. Given a set <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> of periodic aggregation queries, each query <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i</sub> ∈ <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> has its own period <b xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</b> <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i</i> and the subset of source nodes <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Si</i> containing the data. We first propose a family of efficient and effective real-time scheduling protocols that can answer every job of each query task <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i</sub> ∈ <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> within a relative delay <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">O</i> ( <b xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</b> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i</sub> ) under resource constraints by addressing the following tightly coupled tasks: routing, transmission plan constructions, node activity scheduling, and packet scheduling. Based on our protocol design, we further propose schedulability test schemes to efficiently and effectively test whether, for a set of queries, each query job can be finished within a finite delay. Our theoretical analysis shows that our methods achieve at least a constant fraction of the maximum possible total utilization for query tasks, where the constant depends on wireless interference models. We also conduct extensive simulations to validate the proposed protocol and evaluate its practical performance. The simulations corroborate our theoretical analysis.

A New Cooperative Transmission Metric in Wireless Sensor Networks to Minimize Energy Consumption per Unit Transmit Distance

In this letter, we propose a new metric for energy-efficient cooperative transmission in wireless sensor networks (WSN) where the circuit energy consumption is taken into consideration. Under the guide of the new metric, we optimize the energy consumption per unit transmit distance by selecting the appropriate number of cooperative nodes and the transmit energy consumption. In this way, we provide a new point of view to achieve the energy-efficient cooperative transmission, and the proposed metric can be applied in clustered multi-hop sensor networks to transmit data to an appropriate next relay cluster far away from the former cluster.

Catching Packet Droppers and Modifiers in Wireless Sensor Networks

Packet dropping and modification are common attacks that can be launched by an adversary to disrupt communication in wireless multihop sensor networks. Many schemes have been proposed to mitigate or tolerate such attacks, but very few can effectively and efficiently identify the intruders. To address this problem, we propose a simple yet effective scheme, which can identify misbehaving forwarders that drop or modify packets. Extensive analysis and simulations have been conducted to verify the effectiveness and efficiency of the scheme.

Near Optimal Power and Rate Control of Multi-Hop Sensor Networks With Energy Replenishment: Basic Limitations With Finite Energy and Data Storage

Renewable energy sources can be attached to sensor nodes to provide energy replenishment for extending the battery life and prolonging the overall lifetime of sensor networks. For networks with replenishment, conservative energy expenditure may lead to missed recharging opportunities due to battery capacity limitations, while aggressive usage of energy may result in reduced coverage or connectivity for certain time periods. Thus, new power allocation schemes need to be designed to balance these seemingly contradictory goals, in order to maximize sensor network performance. In this paper, we study the problem of how to jointly control the data queue and battery buffer to maximize the long-term average sensing rate of a wireless sensor network with replenishment under certain QoS constraints for the data and battery queues. We propose a unified algorithm structure and analyze the performance of the algorithm for all combinations of finite and infinite data and battery buffer sizes. We also provide a distributed version of the algorithm with provably efficient performance.

Learning and Self-organization for Spatiotemporal Systems

This article deals with the modeling and management of spatiotemporal systems using machine learning and self-organization algorithms. Two application examples are the localization of objects from radio measurements using spatiotemporal models learned from data, and the self-organizing management of wireless multi-hop sensor networks. For both examples we show how machine learning and self-organization significantly increases accuracy and efficiency.

Cooperative Space-Time Block Codes for Wireless Video Sensor Networks

Wireless video sensor networks (WVSNs) are gaining popularity due to numerous potential applications such as video surveillance, environmental and habitat monitoring, and so on. Considering large-scale WVSNs, in which the sink node is not within the range of all other nodes, a multi-hop operation is desired. This paper proposes a novel cooperative system that uses space time-block codes to enhance the performance of multi-hop wireless video sensor networks. The proposed scheme is designed to deal with large-scale WVSNs, by adapting the cluster size and extending the cooperation between the cluster-heads. The performance comparison between the proposed system and a non-cooperative scheme is presented based on network lifetime for varying propagation scenarios, number of camera nodes, and on the quality of transmitted videos in a WVSN. Simulation results show an improvement in performance for the proposed system.

Data Compression by Temporal and Spatial Correlations in a Body-Area Sensor Network: A Case Study in Pilates Motion Recognition

We consider a body-area sensor network (BSN) consisting of multiple small, wearable sensor nodes deployed on a human body to track body motions. Concerning that human bodies are relatively small and wireless packets are subject to more serious contention and collision, this paper addresses the data compression problem in a BSN. We observe that, when body parts move, although sensor nodes in vicinity may compete strongly with each other, the transmitted data usually exist some levels of redundancy and even strong temporal and spatial correlations. Unlike traditional data compression approaches for large-scale and multihop sensor networks, our scheme is specifically designed for BSNs, where nodes are likely fully connected and overhearing among sensor nodes is possible. In our scheme, an offline phase is conducted in advance to learn the temporal and spatial correlations of sensing data. Then, a partial ordering of sensor nodes is determined to represent their transmission priorities so as to facilitate data compression during the online phase. We present algorithms to determine such partial ordering and discuss the design of the underlying MAC protocol to support our compression model. An experimental case study in Pilates exercises for patient rehabilitation is reported. The results show that our schemes reduce more than 70 percent of overall transmitted data compared with previous approaches.

On Energy for Progressive and Consensus Estimation in Multihop Sensor Networks

This paper addresses a transmission energy problem for distributed (or decentralized) estimation in multihop wireless sensor networks (WSN). A primary advantage of distributed estimation is its energy efficiency when compared to centralized estimation. Two distributed estimation schemes are considered in this paper: progressive estimation and consensus estimation. We develop a generalized energy planning algorithm for a progressive estimation method which exploits routing tree and channel state information. We also analyze the energy cost for a consensus estimation method used in broadcast multihop WSN. We demonstrate by analysis and simulation that, subject to an equivalent performance, the total energy cost for consensus estimation is typically much higher than that for progressive estimation, but the peak energy for the former can be less than that for the latter.

Energy-Efficient Algorithm for Sensor Networks with Non-Uniform Maximum Transmission Range

In wireless sensor networks (WSNs), the energy hole problem is a key factor affecting the network lifetime. In a circular multi-hop sensor network (modeled as concentric coronas), the optimal transmission ranges of all coronas can effectively improve network lifetime. In this paper, we investigate WSNs with non-uniform maximum transmission ranges, where sensor nodes deployed in different regions may differ in their maximum transmission range. Then, we propose an Energy-efficient algorithm for Non-uniform Maximum Transmission range (ENMT), which can search approximate optimal transmission ranges of all coronas in order to prolong network lifetime. Furthermore, the simulation results indicate that ENMT performs better than other algorithms.

Performance–lifetime tradeoff for source extraction in multihop sensor networks

AbstractThis paper intends to reveal the performance–lifetime tradeoff for source extraction in a multihop sensor network. The randomly deployed sensor network consists of multiple independent branches. The leaf node in each branch takes an observation from the sensing field. The observation is assumed to be a noisy instantaneous linear mixture of the sources. To account for the bandwidth constraint, each leaf node quantizes its observation and sends the quantized data to the sink in a multihop fashion. The observed mixtures are reconstructed at the sink and are utilized to extract the sources. The accumulated bit error probability in each branch depends on the number of hops and the bit error probability of each channel in that branch. The communication errors affect the accuracy of reconstructing mixtures, and hence affect the performance of source extraction. Network lifetime is defined and analyzed under both per‐sensor energy constraint and network energy constraint. The tradeoff between performance and network lifetime is described by optimization problems and the conditions for optimization are identified. As a by‐product, the conditions for maximizing the network lifetime are also identified. Simulation results demonstrate that the tradeoff exists under certain situations. Copyright © 2010 John Wiley &amp; Sons, Ltd.