Game-based communication in Network Control Systems

Network based Control Systems (NCSs) are more and more often selected in designing distributed control systems due to both economic and practical reasons. Today designs of NCSs frequently involve the non-expensive wireless communication instead of traditional wired links. Such systems are usually calledWireless Sensor Networks (WSNs) and are used for many other purposes as well. While convenient in installation and management, wireless links are susceptible to noise and not very reliable. While common approach of data delivery relies on routing (proactive or reactive), this paper presents a different approach to designing wireless NCSs. In the proposed approach every node takes an independent decision as a result of a game between the nodes. Unlike the routing solutions, the nodes never create any path, and even have no knowledge concerning network topology

An optimal sliding mode congestion controller for connection-oriented communication networks with lossy links

A new discrete-time sliding-mode congestion controller for connection-oriented networks is proposed. Packet losses which may occur during the transmission process are explicitly taken into account. Two control laws are presented, each obtained by minimizing a different cost functional. The first one concentrates on the output variable, whereas in the second one the whole state vector is considered. Weighting factors for adjusting the influence of the control signal and appropriate (state or output) errors are incorporated in both the functionals. The asymptotic stability of the closed-loop system is proved, and the conditions for 100% bottleneck node bandwidth utilization are derived. The performance of the proposed algorithm is verified by computer simulations

Active queue management with discrete sliding modes in TCP networks

In this paper, a new active queue management (AQM) algorithm for data traffic control in TCP/IP networks is developed. The algorithm design is based on the principles of discrete sliding-mode control. Unlike majority of earlier studies, the design procedure considers the effects of both non-negligible delay in transferring data and feedback information and unpredictable capacity variations. The switching function is selected to incorporate a delay compensation mechanism, which ensures efficient network operation even for large bandwidthdelay product connections. The proposed algorithm, implemented as a packet marking scheme, is tested in discrete event ns-2 simulator. The results show that the algorithm provides fast convergence to steady state after sudden, unanticipated capacity changes. By generating smaller overshoots, the proposed algorithm also allows for reducing buffer space requirements to avoid packet loss as compared to the benchmark AQM solutions