OS design challenges & research opportunities in real-time WSNs & approach for real time support in Nano-RK

In recent years, wireless sensor network has become an important research domain. WSNs were initially proposed in domains where ordinary networks (not necessarily wired) are not convenient, either because of the missing infrastructures, or when numerous nodes (in the order of hundreds or thousands) are needed to achieve the assigned task. Nowadays WSNs represent a new generation of distributed embedded systems with a broad range of real-time applications. Some of the applications include process control, fire monitoring, border surveillance, medical care, asset tracking, agriculture, highway traffic coordination etc. Such systems need heavy computations & must meet new kinds of timing constraints under severe resource limitations & limited communication capabilities in highly dynamic environments. Bounded end-to- end delay and guaranteed Quality of Service is also expected. So it is highly necessary to have a common software framework that allows smooth and speedy development of the wide range of proposed sensor applications. An operating system can serve this purpose. Operating systems for WSNs should comprise abstractions that handle digital and analog sensors, provide a communication protocol stack, and make efficient use of the system's limited energy capability. Moreover, OSs should provide an interface and a simple configuration system for application developers [2]. The purpose of this survey is to highlight major concerns pertaining to OS design & research challenges in OS for WSNs in real time applications