Multimedia Sensor Nodes Research Articles

An Acoustic-Visual Collaborative Hybrid Architecture for Wireless Multimedia Sensor Networks

Prolongation of the lifetime has become a key challenge in design and implementation of Wireless Multimedia Sensor Networks (WMSNs). The energy consumed in multimedia sensor nodes is much more than in the scalar sensors; a multimedia sensor captures images or acoustic signals containing a huge amount of data while in the scalar sensors a scalar value is measured (e.g., temperature). On the other hand, given the large amount of data generated by the visual nodes, both processing and transmitting image data are quite costly in terms of energy in comparison with other types of sensor networks. Therefore, energy efficiency is a main concern in WMSNs. In this paper an energy efficient collaborative mechanism for monitoring is proposed. The proposed scheme employs a mixed random deployment of acoustic and visual sensor nodes. Acoustic sensors detect and localize the occurred event/object(s) in a duty-cycled manner by sampling the received signals and then trigger the visual sensor nodes covering the objects to monitor them. Hence, visual sensors are warily scheduled to be awakened just for monitoring the object(s) detected in their domain, otherwise they save their energy.

A Novel Analytical Model for Provisioning QoS in Body Area Sensor Networks

Wireless Body Area Network (WBAN) has been an active area of research over the past few years due to its tremendous benefits particularly related to healthcare systems. The available research to evolve the QoS in WBAN is immature due to lack of sufficient methodology for modeling the behaviour of different kinds of traffic being generated from different kinds of events. It has been clearly demonstrated that traffic found in multimedia sensor nodes being used in WBAN is having bursty nature and cannot be modeled by using Poisson traffic distributions. However, most of the current available literature of traffic modeling related to Multimedia Wireless Sensor Networks (MWSNs) is based on Poisson distributions. To eliminate these kinds of performance evaluation limitations in MWSNs especially in time critical applications, this study proposes a novel analytical framework that relies on a traffic model resembling to an ON/OFF process. Proposed model exhibit self-similar behaviour and is capable to handle long range dependent traffic patterns. For providing enhanced QoS, proposed model deals with various traffic classes that has been judged in the current study through G/M/1 queuing system with a distinct scheduling strategy called as Low Latency Queuing (LLQ) to extract QoS performance metrics such as delay, queue length, throughput and packet loss rate (PLR). We also simulate the behaviour of traffic to further validate the proposed analytical framework.

Improving Path-Coverage for Moving Targets in Wireless Multimedia Sensor Networks

Aimed at the path coverage problem for wireless multimedia sensor networks, MTPCA (Moving Target based Path Coverage-enhancing Algorithm) algorithm is proposed. This algorithm introduces the improved probabilistic model into the virtual potential field based directional sensor network coverage. In order to correct the centroid position of sector area covered by sensor node in traditional probabilistic model, this algorithm puts forward the concept of coverage impact factor to obtain better coverage effect. Furthermore, in MTPCA, multimedia sensor nodes acquire the real-time position information of target point through the discretization of the path curve. In this way, we further adjust the moving directions of each sensor to completely cover all the points along with the path curve. And meanwhile, for the sensing overlapping regions, according to the master active node selection criteria, MTPCA makes no-master nodes asleep for the purpose of energy-saving. The simulation results show that the algorithm can optimize the resource allocation, achieve the satisfactory coverage ratio, and extend the network lifetime. Index Terms—Wireless multimedia sensor networks (WMSN), path coverage, moving target, energy efficiency, virtual potential force, probabilistic model

Node correlation clustering algorithm for wireless multimedia sensor networks based on overlapped FoVs

In this paper, a clustering algorithm is proposed based on the high correlation among the overlapped field of views for the wireless multimedia sensor networks. Firstly, by calculating the area of the overlapped field of views (FoVs) based on the gird method, node correlations have been obtained. Then, the algorithm utilizes the node correlations to partition the network region in which there are high correlation multimedia sensor nodes. Meanwhile, in order to minimize the energy consumption for transmitting images, the strategy of the cluster heads election is proposed based on the cost estimation, which consists of signal strength and residual energy as well as the node correlation. Simulation results show that the proposed algorithm can balance the energy consumption and extend the network lifetime effectively.

A Novel Image Mosaicking Algorithm for Wireless Multimedia Sensor Networks

The wisdom tourism is an important application of internet of things industry, and many cities in China have paid attention to the development of wisdom tourism, such as the national historic city of Zhenjiang. How to take advantage of the cooperation among sensor nodes to obtain the panoramic information of scenic spots is a challenging issue for the wisdom tourism. However, the existing image mosaic algorithms are not suitable for wireless multimedia sensor networks (WMSNs) due to the resource-constrained multimedia sensor nodes, such as energy, computing, and storage space. And hence an image mosaic algorithm based on phase correlation and weighted average (IMBPW) is proposed in this paper. The IMBPW algorithm uses the phase correlation based on Fourier transform to achieve the registration of translation, rotation, and scaling images. After the image registration, the adaptive weighted average algorithm is proposed to do the image fusion. The simulation experiments show that compared with homogeneous algorithms, the IMBPW algorithm has higher real-time and fast convergence speed. Furthermore, the simulation results also show that the proposed algorithm can improve the accuracy of image registration, reduce the complexity of the image mosaic, and prolong the network lifetime while providing better image quality.

Editorial for Chinacom2012 Special Issue

Editorial: This special issue focuses on the most recent advances in the frontier research of wireless communications and networking, and features five high quality papers selected from the conference CHINACOM2012 and open call. CHINACOM2012 is the 7th International Conference on Communications and Networking in China, which was held successfully in Kunming, China, in August 8–10, 2012. The conference has received 416 submissions from 15 countries and is composed of eight technical symposiums, five workshops and two popular tutorials. High quality papers were selected from the proceeding of CHINACOM2012, extended to a journal version and peer-reviewed. Submissions were also received from open call. Five featured outstanding papers are accepted for the publication in this special issue, covering various cuttingedge new techniques in wireless communications and networking, including beamforming, traffic classification, energy saving, routing and realization. The first paper “Robust Filter-and-Forward Beamforming Design for Two-Way Multi-Antenna Relaying Networks” by Zesong Fei, Niwei Wang, Chengwen Xing, Shuo Li, Jiqing Ni and Jingming Kuang investigates a system with multiple two-way relays assisting two terminals to exchange information. A robust filter-and-forward beamforming design is proposed for multi-antenna relays. Aiming at maximizing the signal-to-interference-plus-noise-ratio (SINR), the design problem can be solved by convex optimization tools. Simulation results show that the proposed scheme is less sensitive to the channel estimation errors. The second paper “FFT Traffic Classification-Based Dynamic Selected IP Traffic Offload Mechanism for LTE HeNB Networks” by Xue Han, Lin Han, Yiqing Zhou, Liang Huang, Manli Qian, Jinlong Hu and Jinglin Shi focuses on the traffic offloading in long term evolution (LTE) networks. A dynamic Selected IP Traffic Offload scheme is proposed, which combines the Fast Fourier Transform (FFT) based IP traffic classification scheme with the dynamic traffic offload path selection algorithm. The proposed scheme is shown to be able to realize on-line traffic classification with similar precisions using only less than 10 % of the time required by existing schemes. The third paper “Lifetime Optimization by Load-Balanced and Energy Efficient Tree in Wireless Sensor Networks” by Junhong Ye, Kai Peng, Chonggang Wang, Yake Wang, Liang Zhang, Xiaoqiang Ma and Hongbo Jiang focuses on energy efficient data gathering in wireless sensor networks. A LoadBalanced and energy efficient Tree algorithm is proposed to maximize the lifetime of sensor nodes. The upper bound of network lifetime is presented for data gathering without aggregation with tree-based topology. Simulations demonstrate that the proposed algorithm utilizes up to 98 % of the total energy and provides longer network lifetime than existing methods. The next paper “A Beacon-less Geographic Multipath Routing Protocol for Ad Hoc Networks” by Ping Dong, Huanyan Qian, Xiaofei Wei, Shaohua Lan and Cunlai Pu presents a multipath routing protocol to construct maximally nodedisjoint multiple paths. The proposed protocol utilizes location information to discover multiple paths, thus avoids lot of control messages caused by route discovery andmaintenance in the topology based protocols. Simulation results show that the proposed protocol improves the efficiency of the path discovery, reduces the control overhead and provides relatively short end-to-end delay. The last paper “Design Cooperative Awareness Nodes Using SOPC in Smart Multimedia Sensor Networks” by Yi Zhou, Huiping Li, ChunlinWan and Yandong Hou focuses on the design of the smart cooperative multimedia sensor node based on system on programmable chip (SOPC). Aiming at Y. Zhou (*) Wireless Communication Research Center, Institute of Computing Technology, Chinese Academy of Sciences, Beijing, China e-mail: zhouyiqing@ict.ac.cn

Design cooperative awareness nodes using SOPC in smart multimedia sensor networks

The design mind of SOPC (System on Programmable Chip), hardware & software co-design, will bring the system optimization with larger degree of freedom. It will establish the foundation on realizing the miniaturization and more efficient local preprocessing in smart cooperative sensor networks. In this contribution, a solution is proposed for smart multimedia sensor nodes based on the SOPC framework, aiming at improving the on-board processing capability and the degree of freedom in development. This paper mainly presents the structure and design method of the smart cooperative multimedia sensor node based on SOPC. The on-board feature extraction is realized and some correlative experimental data and results are presented as well. The experimental results evaluate the feasibility and efficiency of the proposed node design method.

In situ image processing capabilities of ARM-based micro-controllers

Dealing with visual data is the key for environmental monitoring tasks in Wireless Multimedia Sensor Networks (WMSNs). Tasks such as object detection, recognition, and/or tracking do require extracting and using the right information from the inherently large amount of visual data. The widely accepted solution of legacy WSNs, transmitting the acquired data to a central base station for further processing, would render a WMSN totally useless because of the unacceptable use of bandwidth and energy. Therefore, we consider the in situ processing as a viable solution for WMSNs. However, processing power and memory capacity restrictions of existing multimedia sensor nodes along with their power consumption are the limiting factors for wide-spread use of in situ processing. Nevertheless, recent technological improvements and introduction of the new ARM cores encourage us to evaluate the image processing capabilities of ARM7/ARM9/ARM11 based micro-controllers for in situ processing in WMSNs. In this work, we first discussed the architectural design differences among the various ARM cores. Then we classified image processing algorithms into three categories. Then, we evaluated the performance of each microcontroller by running a set of basic image processing algorithms necessary for object detection, recognition, and/or tracking. The test results show that ARM11 runs up to 6---30 times faster than ARM9 and ARM7, respectively. Besides, ARM11 consumes up to 5---7 times less energy than ARM9 and ARM7 for the same type of operations.

A collaborative node management scheme for energy-efficient monitoring in wireless multimedia sensor networks

Clustering in sensor networks provides energy conservation, network scalability, topology stability, reducing overhead and also allows data aggregation and cooperation in data sensing and processing. Wireless Multimedia Sensor Networks are characterized for directional sensing, the Field of View (FoV), in contrast to scalar sensors in which the sensing area usually is more uniform. In this paper, we first group multimedia sensor nodes in clusters with a novel cluster formation approach that associates nodes based on their common sensing area. The proposed cluster formation algorithm, called Multi-Cluster Membership (MCM), establishes clusters with nodes that their FoVs overlap at least in a minimum threshold area. The name of Multi-Cluster Membership comes from the fact that a node may belong to multiple clusters, if its FoV intersects more than one cluster-head and satisfies the threshold area. Comparing with Single-Cluster Membership (SCM) schemes, in which each node belongs to exactly one cluster, because of the capability of coordination between intersected clusters, MCM is more efficient in terms of energy conservation in sensing and processing subsystems at the cost of adding complexity in the node/cluster coordination. The main imposed difficulty by MCM, is the coordination of nodes and clusters for collaborative monitoring; SCMs usually assign tasks in a round-robin manner. Then, as second contribution, we define a node selection and scheduling algorithm for monitoring the environment that introduces intra and inter-cluster coordination and collaboration, showing how the network lifetime is prolonged with high lifetime prolongation factors particularly in dense deployments.

An interactive cluster-based MDS localization scheme for multimedia information in wireless sensor networks

A wide range of applications used in wireless sensor networks requires location information of multimedia sensor nodes. In general, the topographical location information of data acquired by a sensor is applied for smart, interactive multimedia services. However, conventional techniques employ GPS or other location-tracking devices installed on sensor nodes and thus incur additional costs, making it impractical for wireless sensor networks. In contrast, some methods provide location information by node connectivity only. One of these methods, called multidimensional scaling – MAP (MDS-MAP), provides the most accurate positioning to date. However, MDS-MAP has a computational overhead of O(n3) in a network of n nodes and, in particular, results in significant localization accuracy error in environments with holes. Thus, this paper proposes a cluster-based MDS (CMDS) for range-free localization that overcomes the shortcomings of MDS and yields smaller accuracy error in all environments. Simulations demonstrate the proposed CMDS approach provides up to 23% improvement in localization accuracy compared to the newest version of conventional MDS-MAP, hierarchical MDS (HMDS) in a sensor network environment with holes.

Perceptual quality‐based image communication service framework for wireless sensor networks

ABSTRACTWireless multimedia sensor networks (WMSNs) have an increasing variety of multimedia‐based applications including image and video transmission. In these types of applications, multimedia sensor nodes should ideally maximize perceptual quality and minimize energy expenditures in communication. For the required perceptual quality to be obtained, quality‐aware routing is a key research area in WMSNs. However, mapping the system parameters to the end user's perceptual quality‐of‐service measures is a challenging task because of incomplete identification metrics. Unfortunately, unless disputable assumptions and simplifications are made, optimal routing algorithm is not tractable. In this paper, we propose a novel image transmission framework to optimize both perceptual quality and energy expenditure in WMSNs. Our framework aims to provide acceptable perceptual quality at the end user by using an analytical distortion prediction model that is able to predict the image distortion resulting from any given error pattern. The innovation of the proposed scheme lies in the combined use of a content‐aware packet prioritization with an energy‐aware and quality‐aware routing protocol, named as image quality‐aware routing. Additionally, it does not only propose an energy‐efficient route selection policy but also manages the network load according to the energy residues of nodes, thus leading to a great energy economy. The results reveal that the framework is capable of identifying true metrics for mapping required image quality to network parameters. Copyright © 2011 John Wiley & Sons, Ltd.

A Method for Clustering and Cooperation in Wireless Multimedia Sensor Networks

Wireless multimedia sensor nodes sense areas that are uncorrelated to the areas covered by radio neighbouring sensors. Thus, node clustering for coordinating multimedia sensing and processing cannot be based on classical sensor clustering algorithms. This paper presents a clustering mechanism for Wireless Multimedia Sensor Networks (WMSNs) based on overlapped Field of View (FoV) areas. Overlapping FoVs in dense networks cause the wasting of power due to redundant area sensing. The main aim of the proposed clustering method is energy conservation and network lifetime prolongation. This objective is achieved through coordination of nodes belonging to the same cluster to perform assigned tasks in a cooperative manner avoiding redundant sensing or processing. A paradigm in this concept, a cooperative scheduling scheme for object detection, is presented based on the proposed clustering method.

A QoS-Based Multichannel MAC Protocol for Two-Tiered Wireless Multimedia Sensor Networks

Rapid penetration of small customized wireless devices and enormous growth of wireless communication technologies has already set the stage for large-scale deployment of wireless sensor networks. Offering precise quality of service (QoS) for multimedia transmission over sensor networks has not received significant attention. However offering some better QoS for wireless multimedia over sensor networks raises significant challenges. In this paper, we propose an adaptive Cross-Layer multi-channel QoS-MAC protocol to support energy-efficient, high throughput, and reliable data transmission in Wireless Multimedia Sensor Network (WMSNs). Our proposed protocol use benefit of TDMA and CSMA/CA to adaptively assign channels and timeslots to active multimedia sensor nodes in clusters. Simulations show that the proposed system achieves the performance objectives of WMSNs with increased network throughput at the cost of a small control and energy overhead.

Cross Layer Optimization for Data Gathering in Wireless Multimedia Sensor Networks within Expected Network Lifetime

The use of multimedia sensor nodes can significantly enhance the capability of wireless sensor networks (WSNs) for event description. In a number of scenarios, e.g., an erupting volcano, the WSNs are not deployed to work for an extremely long time. Instead, the WSNs aim to deliver continuous and reliable multimedia data as much as possible within an expected lifetime. In this paper, we focus on the efficient gathering of multimedia data in WSNs within an expected lifetime. An adaptive scheme to dynamically adjust the transmission Radius and data generation Rate Adjustment (RRA) is proposed based on a cross layer design by considering the interaction among physical, network and transport layers. We first minimize the end-to-end transmission delay in WSNs while using the minimum data generation rate. In this phase, an optimal transmission radius can be derived. Then, using this transmission radius, we adaptively adjust the data generation rate to increase the amount of gathered data. Simulation results show that the proposed RRA strategy can effectively enhance the data gathering performance in wireless multimedia sensor networks (WMSNs) by dynamically adjusting the transmission radius of sensor nodes and the data generation rate of source nodes.

Transmitting and Gathering Streaming Data in Wireless Multimedia Sensor Networks Within Expected Network Lifetime

Using multimedia sensor nodes in wireless sensor networks (WSNs) can significantly enhance the capability of WSNs for event description. Different kinds of holes can easily appear in WSNs. How to efficiently transmit multi-media streaming data and bypass all kinds of holes is a challenging issue. Moreover, some applications do not need WSNs to work for a long lifetime, e.g. monitoring an erupting volcano. These applications generally expect that WSNs can provide continuous streaming data during a relatively short expected network lifetime. Two basic problems are: (1) gathering as much data as possible within an expected network lifetime; (2) minimizing transmission delay within an expected network lifetime. In this paper, we proposed a cross-layer approach to facilitate the continuous one shot event recording in WSNs. We first propose the maximum streaming data gathering (MSDG) algorithm and the minimum transmission delay (MTD) algorithm to adjust the transmission radius of sensor nodes in the physical layer. Following that the two-phase geographical greedy forwarding (TPGF) routing algorithm is proposed in the network layer for exploring one/multiple optimized hole-bypassing paths. Simulation results show that our algorithms can effectively solve the identified problems.

Self-orienting wireless multimedia sensor networks for occlusion-free viewpoints

Wireless multimedia sensor networks (WMSN) are formations of a large number of compact form-factor computing devices that can capture multimedia content, such as video and audio, and communicate them over wireless channels. The efficiency of a WMSN heavily depends on the correct orientation (i.e., view) of its individual sensory units in the field. In this paper, we study the problem of self-orientation in WMSN, that is finding the most beneficial orientation for all multimedia sensors to maximize multimedia coverage. We propose a new algorithm to determine a node’s multimedia coverage and find the sensor orientation that minimizes the negative effect of occlusions and overlapping regions in the sensing field. Our approach enables multimedia sensor nodes to compute their directional coverage leading to an efficient and self-configurable sensor orientation calculation. By using simulations, we show that the occlusion-free viewpoint approach increases the multimedia coverage significantly. The self-orientation methodology is designed in the form of a distributed algorithm, making it a suitable candidate for deployment in practical systems.