A Robust Path Metric for Mobile Wireless Networks

In this paper, we propose and evaluate a path metric to select robust paths in mobile wireless networks. This path metric selects paths that offer a good trade-off between long routes consisting of many reliable links and short routes consisting of only few but unreliable links. In contrast to the widely used minimum hop count metric, which chooses arbitrarily among those paths with minimum length, our path metric estimates the reliability of a link based on the measured received signal strength (RSSI). Every node determines a preferred signal strength and assigns each neighbor a link cost depending on how close to this strength its RSSI value is. Using simulations with realistic mobility traces of a large city, we compare our path metric to the minimum hop count metric. With nodes moving at car speed, using our metric increases the average route lifetime by a factor of 7 and reduces the packet loss ratio due to route breaks during communication by a factor of up to 15.