Minimização do consumo de energia em sistemas de controle em rede sem fio

Abstract

One of the main 6G uses cases is known as URLLC, which has as necessary requirements the latency, reliability and availability that guarantees the resilience of the system against possible scenarios of unavailability. Also, because of cost and size restrictions at the time of implementation of these systems, it is common for wireless control systems to be powered by batteries. Then, the energy consumed by the system needs to be taken into consideration. Therefore, three scenarios were analyzed to solve the necessary requirements in wireless control systems. The first two scenarios this work focuses on minimizing the energy consumed per successfully transmitted bit, with the constraint that the stability of the control system must be guaranteed. The first scenario used a condition that is sufficient to obtain the stability of the system known as the residence time method. Where it was possible through the optimization of the outage probability, to minimize the power consumption per bit from a closed expression that relates the maximum outage probability that the system can operate with the stability of the control system. With the analysis made from the scenario of the dwell time method, it was concluded that the joint design of communications and control has lower energy consumption than the traditional method in the literature, of minimizing energy given a fixed target outage. The second scenario presented a wireless networked control system (WNCS) with time correlation. The minimization of the energy consumed per bit was given from the optimization of the probability of outage of distributed channels according to a Nakagami-𝑚 distribution correlated in time. Therefore, a closed form expression was obtained for the transmission power that minimizes the amount of energy consumed per bit in this WNCS scenario. The results show that the optimal parameters of outage probability and transmission power depend on the temporal correlation factor present in the communication channel in a wireless network control system. Finally, in the third scenario, we minimize the amount of energy used by a power source with multiple antennas that feed a system with predictive control. In this scenario, it was possible to determine the model of the wireless channel of energy and information transfer and the incident energy statistics for cases of instantaneous or average channel state information. For the respective scenarios, we modeled the probability of outage, taking into account that both links affect the system’s reliability. The results show that the minimum energy will depend on the amount of before in the energy source and the number of predictive control commands. And we concluded that the use of a channel with instant information has less energy is used by the source than a channel with average information.