## 2 Related Work  
As mentioned earlier, how to design an efficient routing algorithm for WSANs that can satisfy both communication and control performances, focusing on the energy consumption of nodes in a network and the control system response is still an open research problem in the current literature. To the best of our knowledge, most research literature related to WSANs focuses on either communication or control separately. There are only a few papers considering the cooperation between the communication and the control in this WSAN research field. Moreover, the energy consumption indicating the lifetime of a network that can significantly influence the resulting control output is not studied in all existing works. A review of related works is given here. References [13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25] propose routing protocols for WSANs; however, the research methodologies of these studies are still similar to approaches in traditional wireless sensor networks (WSNs). They are only interested in communication viewpoints for designing routing algorithms without considering the functions of controllers, actuators and plants/physical systems. In these works, actuators do not perform any actions to change the behavior of environments. Accordingly, the effect of routing algorithms to the resulting control output is not explored. How these proposed routing protocols can appropriately be applied for control applications is still a research question. Reference [26] proposes an adaptive protocol for industrial control applications using WSNs. The design approach depends on a constrained optimization formulation problem. The objective function is to minimize the total energy consumption of nodes in a network, while reliability and latency thresholds are the constraints based on control application requirements. The reliability is defined by the probability of successful packet delivery. The latency is described by the probability of largest end-to-end delay less than the threshold. In [26], the reliability must be higher than 90% and the latency must be achieved at least with a probability of 95%. The experimental results from implemented Tmote testbed demonstrate that the proposed protocol outperforms the IEEE 802.15.4 solution. However, the work in [26] only focuses on wireless network mechanisms and doesn't consider the functions of controllers, actuators and plants in the designs and the implementations. References [29, 30] develop a control mechanism for industrial control systems with WSANs where the unreliable wireless transmission plays a major role. A Bernoulli random variable is employed to model the packet loss due to wireless communication among sensors and actuators. Optimal control decisions and the collaboration among actuators are significantly studied in these works. However, these works only focus on the problem of designing a control strategy to achieve control objectives/to meet user requirements. Wireless network protocols that can greatly influence the control system response are not considered in this investigation. In [3], simulation case studies of wireless networked control systems are presented. The applications considered are the building automation and target tracking cases. The objectives of the investigation are to provide the possibility to study, develop and test integrated wireless communication and control systems by using the simulation tool, namely PiccSIM [31]. This tool is a combination communication and control simulator which is the integration of network simulator version 2 (NS2) and MATLAB/Simulink. Wireless networks are simulated by NS2, while all control parts are simulated by MATLAB/Simulink. Both network protocols and control models are provided to study their performances in this latest work. Additionally, the performance evaluation of localizedmultiple next-hop routing (LMNR) and AODV algorithms in both control cases are explored.