Wireless Sensor Networks (WSNs) consist of small nodes with sensing, computation, and wireless communications capabilities. Many routing, power management, and data dissemination protocols have been specifically designed for WSNs where energy awareness is an essential design issue. The focus, however, has been given to the routing protocols, which might differ depending on the application and network architecture. Overall, the routing techniques are classified into three categories based on the underlying network structure: flat, hierarchical, and location-based routing. Furthermore, these protocols can be classified into multipath-based, query-based, negotiation-based, QoS-based, and Coherent-based depending on the protocol operation. In this paper, WE present a survey on the QOS-based routing technique in WSNs. We first outline the design challenges for QOS-based routing protocols in WSNs followed by future possibilities in QOS-based routing techniques. We study the design tradeoffs between energy and communication overhead savings in this techniques. We also highlight the advantages and performance issues of this routing technique.
