Study of Quality of Service Routing in Wireless Sensor Networks

A wireless sensor network is a collection of a large number of sensors nodes densely deployed. Sensor nodes are used to sense environmental data and collect information at a central place. Sensors have been a regular part in our daily life, they can be very much used in isolation to solve many problems like in car, ac, and to measure temperature, sound, pollution levels, humidity, wind speed direction and pressure. They can be used in isolation. But the important focus is on some crucial applications where human life is associated, environmental is associated for example the battlefields, earth quick monitoring, flood monitoring, weather forecasting etc. These are some of the biggest applications which need the invention of sensor nodes rather than manual human forces. Here sensor nodes cannot work in isolation because one sensor cannot gather appropriate data. Therefore, it is needed to deploy a large number of sensor nodes, which can exchange data through some communication strategy or protocol, and thereafter the data should be maintained to a common place where some action should be taken. For providing efficient applications among these sensor nodes, an efficient routing protocol or algorithm needs which could provide the QoS to the end user. Most of the routing protocols for WSNs are designed without explicitly considering the Quality of Service (QoS) of the generated routes. It has been observed that such routing protocols are inadequate at the time of data delivery route which requires guaranteed QoS. QoS routing requires discovering a route from source to destination to fulfill the QoS necessities. QoS is more complicated to assurance in sensor network due to dynamic topology and energy constraints. In this paper, recent issues and challenges have been considered in terms of research gap yet, QoS routing approaches have been deliberated, distribution of literature over recent years and QoS parameters distribution over recent years have been exposed, which are valuable for researchers for further investigation.