Markov Decision Processes with Applications in Wireless Sensor Networks: A Survey

Wireless sensor networks (WSNs) consist of autonomous and resource-limited devices. The devices cooperate to monitor one or more physical phenomena within an area of interest. WSNs operate as stochastic systems because of randomness in the monitored environments. For long service time and low maintenance cost, WSNs require adaptive and robust methods to address data exchange, topology formulation, resource and power optimization, sensing coverage and object detection, and security challenges. In these problems, sensor nodes are to make optimized decisions from a set of accessible strategies to achieve design goals. This survey reviews numerous applications of the Markov decision process (MDP) framework, a powerful decision-making tool to develop adaptive algorithms and protocols for WSNs. Furthermore, various solution methods are discussed and compared to serve as a guide for using MDPs in WSNs

A critical analysis of research potential, challenges and future directives in industrial wireless sensor networks

In recent years, Industrial Wireless Sensor Networks (IWSNs) have emerged as an important research theme with applications spanning a wide range of industries including automation, monitoring, process control, feedback systems and automotive. Wide scope of IWSNs applications ranging from small production units, large oil and gas industries to nuclear fission control, enables a fast-paced research in this field. Though IWSNs offer advantages of low cost, flexibility, scalability, self-healing, easy deployment and reformation, yet they pose certain limitations on available potential and introduce challenges on multiple fronts due to their susceptibility to highly complex and uncertain industrial environments. In this paper a detailed discussion on design objectives, challenges and solutions, for IWSNs, are presented. A careful evaluation of industrial systems, deadlines and possible hazards in industrial atmosphere are discussed. The paper also presents a thorough review of the existing standards and industrial protocols and gives a critical evaluation of potential of these standards and protocols along with a detailed discussion on available hardware platforms, specific industrial energy harvesting techniques and their capabilities. The paper lists main service providers for IWSNs solutions and gives insight of future trends and research gaps in the field of IWSNs

Cooperative Medium Access Mechanisms and Service-oriented Routing in Multi-hop Wireless Networks

Doktorgradsavhandling i informasjons- og kommunikasjonsteknologi, Universitetet i Agder, Grimstad, 2011Multi-hop wireless networks have been regarded as a promising path towards future wireless communication landscape. In the past decade, most related work has been performed in the context of mobile ad hoc networks. In very recent years, however, much effort has been shifted to more static networks such as wireless mesh networks and wireless sensor networks. While significant progress has been achieved through these years, both theoretically and experimentally, challenges still exist in various aspects of these networks. For instance, how to use multi-hop networks as a means for providing broadband Internet services with reliability and balanced load remains as a challenging task. As the number of end-users is increasing rapidly and more and more users are enjoying multimedia services, how to provide Quality of Service (QoS) with user satisfaction in such networks remains also as a hot topic. Meanwhile, another direction which has recently attracted lots of efforts in the international research community is the introduction of cooperative communications. Cooperative communications based on relaying nodes are capable of improving network performance in terms of increased spectral and power efficiency, extended network coverage, balanced QoS, infrastructure-less deployment, etc. Cooperation may happen at different communication layers, at the physical layer where the received signal is retransmitted and at the MAC and routing layers where a packet is forwarded to the next hop in a coordinated manner towards the destination, respectively. However, without joint consideration and design of physical layer, MAC layer and network layer, the benefit of cooperative communication cannot be exploited to the maximum extent. In addition, how to extend one-hop cooperative communication into multi-hop wireless network scenarios remains as an almost un-chartered research frontier. In this dissertation, we enhance the state of the art technologies in the field of multi-hop wireless networks from a layered perspective. While efficient scheduling mechanisms are proposed at the MAC layer, elaborate routing protocols are devised at the network layer. More specifically, by taking into account of cross layer design we cope with network congestion problems in wireless mesh networks mainly at the network layer. In order to further improve the performance of cooperative wireless networks, we propose a contention-based cooperative MAC protocol in the presence of multiple relay nodes. Since a large majority of existing cooperative MAC protocols are designed based on widely-used IEEE 802.11 MAC protocol which exhibits inherent design constraint when applied in multi-hop wireless networks, it is imperative to develop a novel cooperative MAC protocol which is appropriate for multi-hop network scenarios. Next, we propose a TDMA-based MAC protocol supporting cooperative communications in static multi-hop wireless networks. Furthermore, a cooperative lifetime maximization MAC protocol is proposed to cope with the energy hole problem in wireless sensor networks

Over-the-air software updates in the internet of things : an overview of key principles

Due to the fast pace at which IoT is evolving, there is an increasing need to support over-theair software updates for security updates, bug fixes, and software extensions. To this end, multiple over-the-air techniques have been proposed, each covering a specific aspect of the update process, such as (partial) code updates, data dissemination, and security. However, each technique introduces overhead, especially in terms of energy consumption, thereby impacting the operational lifetime of the battery constrained devices. Until now, a comprehensive overview describing the different update steps and quantifying the impact of each step is missing in the scientific literature, making it hard to assess the overall feasibility of an over-the-air update. To remedy this, our article analyzes which parts of an IoT operating system are most updated after device deployment, proposes a step-by-step approach to integrate software updates in IoT solutions, and quantifies the energy cost of each of the involved steps. The results show that besides the obvious dissemination cost, other phases such as security also introduce a significant overhead. For instance, a typical firmware update requires 135.026 mJ, of which the main portions are data dissemination (63.11 percent) and encryption (5.29 percent). However, when modular updates are used instead, the energy cost (e.g., for a MAC update) is reduced to 26.743 mJ (48.69 percent for data dissemination and 26.47 percent for encryption)

Emerging Communications for Wireless Sensor Networks

Wireless sensor networks are deployed in a rapidly increasing number of arenas, with uses ranging from healthcare monitoring to industrial and environmental safety, as well as new ubiquitous computing devices that are becoming ever more pervasive in our interconnected society. This book presents a range of exciting developments in software communication technologies including some novel applications, such as in high altitude systems, ground heat exchangers and body sensor networks. Authors from leading institutions on four continents present their latest findings in the spirit of exchanging information and stimulating discussion in the WSN community worldwide

A Comprehensive Analysis of Literature Reported Mac and Phy Enhancements of Zigbee and its Alliances

Wireless communication is one of the most required technologies by the common man. The strength of this technology is rigorously progressing towards several novel directions in establishing personal wireless networks mounted over on low power consuming systems. The cutting-edge communication technologies like bluetooth, WIFI and ZigBee significantly play a prime role to cater the basic needs of any individual. ZigBee is one such evolutionary technology steadily getting its popularity in establishing personal wireless networks which is built on small and low-power digital radios. Zigbee defines the physical and MAC layers built on IEEE standard. This paper presents a comprehensive survey of literature reported MAC and PHY enhancements of ZigBee and its contemporary technologies with respect to performance, power consumption, scheduling, resource management and timing and address binding. The work also discusses on the areas of ZigBee MAC and PHY towards their design for specific applications