QoS in Wireless Sensor Networks

Wireless Sensor Networks (WSNs) have been envisioned as a new and effective means for creating and deploying previously unimaginable applications. These networks generally have the capabilities of observing the physical phenomena, communication, data processing and dissemination. Limited resources of sensor nodes like energy, bandwidth and processing abilities, make these networks excellent candidates for incorporating QoS framework. The possible applications of WSNs are numerous while being diverse in nature which makes analyzing and designing QoS support for each application a nontrivial task. At the same time, these applications require different type of QoS support from the network for optimum performance. A single layer cannot address all these issues, hence, numerous researchers have proposed protocols and architectures for QoS support at different network layers. In this chapter, the authors identify the generic QoS parameters which are usually supported at different layers of WSNs protocol stack and investigate their importance in different application models. A brief overview of significant research contribution at every network layer is provided. It is worthwhile to mention that same QoS parameter may be supported at multiple layers, hence, adequate selection of suitable mechanism would be application’s choice. On the other hand, it is quite possible that a single QoS parameter, such as energy conservation or real-time delivery, can be efficiently supported through interaction of multiple layers. It is difficult, if not impossible to optimize multi layer QoS architecture. Hence, a number of researchers have also proposed the idea of cross layer architecture for providing QoS support for a number of sensor applications, which is also discussed in this chapter. At the end, the authors highlight the open research issues that might be the focus of future research in this area.