Fault-impact models based on delay and packet loss for IEEE 802.11g

In this paper we derive fault-impact models for wireless network traffic as it could be used in the control traffic for smart grid nodes. We set up experiments using a testbed with 116 nodes which uses the protocol IEEE 802.11g. We develop models for packet loss, the length of consecutive packet loss or non-loss as well as for packet transmission time. The latter is a known challenge and we propose a sampling technique that benefits from the wireless as well as wired connections between the nodes in the testbed. The data obtained shows similarity with previous measurements. However, we progress the state of the art in two ways: we show measurements of packet transmission times and fit models to those and we provide some more detailed insight in the data. We find that with increasing link quality, the distributions of lossy and loss-free periods show major fluctuation. It is shown that in those cases, phase-type distributions can approximate the data better than traditional Gilbert models. In addition, the medium access time is also found to be approximated well with a PH distribution