State of the Art on Energy-Efficient and Latency-Constrained Networking Protocols for Wireless Sensor Networks
Annette Böhm · KTH Publication Database DiVA (KTH Royal Institute of Technology) · 2007
Advances in the development and integration of small battery-powered sensing devices have enabled the design of applications where a group of sensors cooperate in monitoring their environment. Wireless sensor networks (WSN) are today used in a wide variety of areas like e.g. habitat monitoring, battle field surveillance, disaster management, health monitoring or industrial control. Their applicability is often reduced by limitations in the sensor nodes power supply, communication bandwidth, processing capabilities and buffer size. Many researchers have put effort in overcoming these shortcomings, with a special focus on maximizing the battery lifetime of a single node as well as the lifetime of the network as a whole. A list of possible applications can be found in [Akyildiz]. As applications become more and more mission-critical, it is crucial that the collected sensor data arrive at the sink within a specified time limit. Guaranteeing a certain quality of service (QoS) to a user or an application is difficult because of the unpredictable nature of the wireless link and the often unstable topology of the sensor network (due to node failure or mobility). Very little research has been done in the field of QoS for WSNs [Chen] [Wang] and many interesting research questions are still unanswered. This state-of-the-art document aims at giving an overview on routing and medium access issues in WSNs and at summarizing some of the most interesting solutions. The requirements on WSN protocols are very dependent on the application in which the WSN will be used. Aspects as energy-efficiency, latency, Quality of Service (QoS), mobility, distribution density or cost all influence the choice of protocol and its parameters. There is therefore no single protocol that matches all types of WSN and the best results can only be achieved by tailoring the protocol for a specific application or scenario. In this state-of-the-art report, we make certain assumptions, loosely based upon the requirements of a surveillance application.