WSANs provide the infrastructure for many applications of CPS. Lots of these applications use the IEEE 802.15.4 standard. However, it does not provide any means of differentiated services to improve QoS for time-critical and delay-sensitive events. A large amount of efforts have been made to address such issues. In this chapter, an overview on some interesting mechanisms used in existing adaptive and real-time protocols in compliance with IEEE 802.15.4 is presented. Careful examination of these research works reveals that by optimizing the original specifications and dynamically adjusting the protocol parameters, the total network efficiency can be significantly improved. Nevertheless, there are still certain challenges to overcome in pursuing the most appropriate protocol without introducing unacceptable side-effects. These standards have greatly encouraged to bridge the real-time physical world's applications/objects to cyber world for diverse range of time-critical applications. The communication and computing capabilities of cyber core are utilized to control/monitor real world's objects/applications.
KeywordsThe performance of CPS depends upon QoS of the underlying network. In practice, applications' requirements vary in different environments. For example, in case of environmental surveillance, alarm packet should be prioritized as compared to normal data readings. In WBANs, life critical physiological readings should be delivered on time to the health services provider. However, IEEE 802.15.4 does not have such