Control-Aware Random Access Communication

Abstract

In modern control applications multiple wireless sensors need to efficiently share the available wireless medium to communicate with their respective actuators. Random access policies, where each sensor independently decides whether to access the shared wireless medium, are attractive as they do not require central coordination. However interference between simultaneous transmissions causes transmitted packets to collide, leading to control performance degradation or potentially instability. Given plant and controller dynamics, we derive a sufficient condition for the access policy employed by each sensor so that wireless interference does not violate stability of any involved control loop. Based on this decoupling condition we design random access communication policies that are control-aware by adapting to the physical plant states measured by the sensors online. The control performance of our design is illustrated in numerical simulations.

Wireless Network Design for Control Systems: A Survey

“…On the other hand, [173] derives experimental based models by using curve fitting techniques and validation through extensive experiments. An adaptive algorithm was also proposed to adjust the coefficients of these models by introducing a learning phase without any explicit information about data traffic, network topology, and Contention-based Access [212], [213], [175], [174], [214], [129], [84], [107], [215], [173], [125] [166], [202], [194], [195], [216], [196], [217] [204], [211], [206], [207], [208], [209], [210] Schedule-based Access [126], [127], [176], [177], [178] [4], [190], [203], [202], [192], [193] [81], [218], [205], [62], [83] Physical Layer Extension [6], [87], [183], [219], [220], [221] --Network Resource Schedule Scheduling Algorithm …”

“…Contention-based Access: The tradeoff between the level threshold crossings in the control system and the packet losses in the communication system have been analyzed in [204], [211], [206], [207], [208], [209], [210]. [204] studies the eventtriggered control under lossy communication.…”

Random access design for wireless control systems

“…Hence, system states have second moments that decay exponentially with rate ρ i < 1 and in the limit remain bounded by T r(P i W i )/(1−ρ i ), since the sum in (18) converges. As a technical sidenote, an advantage of the Lyapunov performance approach is that it defines a convex region (a lower bound) for the packet success rate in (11), which is easy to employ in our random access design (17).…”

Prioritized contention resolution for random access networked control systems

“…Careful design of p b is a well-studied topic, see e.g. [13], [19], but is out of scope of this work. Therefore, the probability that a subsystem i successfully transmits at a given time-step k is…”

“…However, prioritization in the original TOD formulation can be realized at the expense of having a centralized coordination unit, which is not often desired in large NCSs due to scalabality issues. Moreover, centralized coordination of medium access is not possible in many scenarios, such as establishing a network connection, which is performed in a decentralized fashion [12], [13]. Connection establishment is envisioned to be the dominating part of the end-to-end delay for future NCS applications, and fast random access is one of the challenges for the evolution of wireless networks towards 5G [12], [14].…”