Low-cost wireless link capacity estimation

Wireless link quality estimations are essential for the optimal operation of various network functions like routing and rate adaptation. In this paper, we present a new link quality metric named Effective Link Capacity (ELC), which predicts link capacity by utilizing information such as the packet delivery ratio (PDR) and the transmission count of data packets (TXC). ELC requires no active probing and hence incurs zero overhead, while using only locally-available information from the transmitting node. Using our conducted testbed, we evaluate the accuracy of ELC on both single link and hidden terminal scenarios, with different configurations of packet sizes, link rates and offered loads. We also corroborate our conducted testbed findings with an evaluation of ELC for varying amounts of offered load on a live wireless data link in an office environment and find that ELC is highly accurate, with a maximum Root Mean Squared Error (RMSE) of 4.43%. We also compare ELC against a known bandwidth estimation tool, PathChirp, and find that ELC's RMSE of 0.68% far outperforms Path Chirp's RMSE of 18.66%.