QoS-aware MAC protocols for wireless sensor networks: A survey <s> Background and QoS perspectives <s> Target tracking systems, consisting of thousands of low-cost sensor nodes, have been used in many application domains such as battlefield surveillance, wildlife monitoring and border security. These applications need to meet certain real-time constraints in response to transient events, such as fast-moving targets. While the real-time performance is a major concern in these applications, it should be compatible with other important system properties such as energy consumption and accuracy. Hence, it is desirable to have the ability to exploit the tradeoffs among them. This work presents the real-time design and analysis of VigilNet, a large-scale sensor network system which tracks, detects and classifies targets in a timely and energy efficient manner. Based on a deadline partition method and theoretical derivations of each sub-deadline, we are able to make guided engineering decisions to meet the end-to-end tracking deadline. To confirm our design and obtain an empirical understanding of these tradeoffs, we invest significant efforts to perform large-scale simulations with 10,000 nodes as well as a field test with 200 XSM motes, running VigilNet. The results from both analysis and evaluation can serve as general design guidelines to build similar real-time systems. <s> BIB001 </s> QoS-aware MAC protocols for wireless sensor networks: A survey <s> Background and QoS perspectives <s> The availability of low-cost hardware such as CMOS cameras and microphones has fostered the development of Wireless Multimedia Sensor Networks (WMSNs), i.e., networks of wirelessly interconnected devices that are able to ubiquitously retrieve multimedia content such as video and audio streams, still images, and scalar sensor data from the environment. In this paper, the state of the art in algorithms, protocols, and hardware for wireless multimedia sensor networks is surveyed, and open research issues are discussed in detail. Architectures for WMSNs are explored, along with their advantages and drawbacks. Currently off-the-shelf hardware as well as available research prototypes for WMSNs are listed and classified. Existing solutions and open research issues at the application, transport, network, link, and physical layers of the communication protocol stack are investigated, along with possible cross-layer synergies and optimizations. <s> BIB002 </s> QoS-aware MAC protocols for wireless sensor networks: A survey <s> Background and QoS perspectives <s> Holding the promise of making ubiquitous mobile access to IP-based applications and services a reality, wireless local area networks have been deployed in an unlimited way over the last few years. Due to their robust characteristics, distributed MAC protocols are the most widely used mechanisms to arbitrate access to the wireless channel. However, their ability to achieve high medium usage efficiency while providing services with meaningful performance assurances is being challenged by a wide range of existing and emerging applications that have lately migrated from other telecommunication networks to wireless environments. This article aims to provide a comprehensive study of the limitations and merits of mechanisms that have been proposed toward embedding QoS support to distributed wireless MAC protocols. A hybrid scheme that incorporates signaling and information sharing is proposed, and extensive simulation experiments are run to assess the efficiency of the access schemes in maximizing utilization of the wireless bandwidth while providing QoS support for heterogeneous applications. <s> BIB003 </s> QoS-aware MAC protocols for wireless sensor networks: A survey <s> Background and QoS perspectives <s> Improving the quality of healthcare and the prospects of "aging in place" using wireless sensor technology requires solving difficult problems in scale, energy management, data access, security, and privacy. We present AlarmNet, a novel system for assisted living and residential monitoring that uses a two-way flow of data and analysis between the front- and back-ends to enable context-aware protocols that are tailored to residents' individual patterns of living. AlarmNet integrates environmental, physiological, and activity sensors in a scalable heterogeneous architecture. The SenQ query protocol provides real-time access to data and lightweight in-network processing. Circadian activity rhythm analysis learns resident activity patterns and feeds them back into the network to aid context-aware power management and dynamic privacy policies. <s> BIB004 </s> QoS-aware MAC protocols for wireless sensor networks: A survey <s> Background and QoS perspectives <s> Visual sensor networks have emerged as an important ::: class of sensor-based distributed intelligent systems, ::: with unique performance, complexity, and quality of service ::: challenges. Consisting of a large number of low-power camera nodes, ::: visual sensor networks support a great number of novel ::: vision-based applications. The camera nodes provide information ::: from a monitored site, performing distributed and collaborative ::: processing of their collected data. Using multiple cameras in the ::: network provides different views of the scene, which enhances ::: the reliability of the captured events. However, the large amount ::: of image data produced by the cameras combined with the ::: network's resource constraints require exploring new means ::: for data processing, communication, and sensor management. ::: Meeting these challenges of visual sensor networks requires ::: interdisciplinary approaches, utilizing vision processing, communications ::: and networking, and embedded processing. In this ::: paper, we provide an overview of the current state-of-the-art in ::: the field of visual sensor networks, by exploring several relevant ::: research directions. Our goal is to provide a better understanding ::: of current research problems in the different research fields of ::: visual sensor networks, and to show how these different research ::: fields should interact to solve the many challenges of visual sensor ::: networks. <s> BIB005
Internet was initially designed for providing the best effort delivery of application data since average performance guarantees were sufficient for initial types of applications BIB003 . However, with the emergence of applications, such as Internet telephony and video streaming, that require high throughput, bounded delay, bounded delay jitter, and high reliability, best effort delivery has become insufficient to support these applications. Consequently, this has driven and enabled the development of algorithms, protocols and mechanisms that provide QoS support for diverse set of applications. A similar situation is currently observed in WSNs. Traditionally, WSNs have been used for monitoring applications based on low-rate data collection with low periods of operation. Current WSNs are considered to support more complex operations ranging from target tracking BIB001 to assisted living BIB004 which require efficient, reliable and timely collection of large amounts of data. Moreover, the recent advances in image sensor technology, have enabled the use of video sensors and this resulted in a new class of WSNs, called visual or multimedia sensor networks BIB002 BIB005 , that can be used for various potential applications, such as telepresence and surveillance. It is certain that, these networks also have tighter QoS requirements, such as low data delay and maximum reliability, compared to traditional WSNs BIB005 .