Search results for "Shared medium"
showing 2 items of 2 documents
Kalman filtering applied to Profibus-DP systems. Multirate control systems with delayed signals
2008
In networked control systems several devices (controllers, sensors and actuators) share a common communication resource. This feature can introduce variable and even random delays when those devices try to transmit information through the shared medium. The limited bandwidth capabilities of the transmission medium also can restrict the freedom to set the sampling periods in the control loop. An attempt to reduce the significance of the signal delays and save to some bandwidth can be based on high values of sampling periods. Usually this solution has remarkable effects in the system performance because with higher sampling periods closed loop response capabilities are decreased. This paper p…
Achieving Fair Bandwidth Distribution in WiFi Networks: A Game Theoretical Approach
2011
International audience; Achieving fair bandwidth distribution among uplink and downlink ows in IEEE 802.11 infrastructure networks is a complex issue, due to the well-known features of the Distributed Coordination Function (DCF) which regulates the access to the shared medium. Indeed, the dynamic adaptation of the contention windows causes phenomena of short-term unfairness, while the use of homogeneous contention parameters among the contending nodes makes the aggregated downlink bandwidth equal to the uplink bandwidth of a single node. We propose a dynamic tuning of the contention parameters used by the nodes, based on simple network monitoring functionalities and rational strategies. Spe…