@InProceedings{IR-EE-RT_2007:043, author = {Maben Rabi and Luca Stabellini and Peter Almstr{\"o}m and Mikael Johansson},title = {Analysis of networked estimation under contention-based medium access},booktitle = {{IFAC} World Congress},year = {2008},month = July, address = {Seoul, South Korea},abstract = {We treat a problem in networked estimation where the focus is on sampling and transmitting measurements of the plant over a shared medium. The object is to choose the sampling rate at the sensor while taking the statistics of a contention based MAC protocol into account. In particular, we seek a trade-off between the reliable delivery of individual data packets and the input data load on the communication medium. Our analysis of the shared channel computes a probability of packet loss for an assumed IID loss process. This loss rate depends on the input packet stream intensities. We compute the estimation distortion with IID losses of periodically generated samples, as a function of the packet loss rate. This throws up a condition for stable estimator performance. We investigate the scalability limits of this stability as a function of the number of nodes. When stable estimation is possible, we provide a procedure that computes the input packet rate for the network that minimizes the average estimation distortion. We reproduce the analysis of estimation performance when the sensors sample asynchronously according to independent Poisson counters.},keywords = {Cross-layer optimization; Estimation over lossy links; Networked Estimation} }