On exploiting asymmetric wireless links via one-way estimation

A substantial percentage of links in wireless networks, especially low-power ones, is asymmetric. For the low-quality direction of asymmetric links, we observe based on testbed experiments that the reliability of synchronous acknowledgments is considerably higher than that of asynchronous messages. Thus the norm of estimating link quality in both directions via asynchronous beacons such as in ETX-based routing potentially underestimates the link reliability of asymmetric links. This leads us to investigate how to exploit asymmetric links in order to improve network functions such as convergecast routing in sensor networks via one-way link estimation. We propose a new one-way link metric ETF (for the expected number of transmissions over forward links) and present a local procedure for its estimation. We use ETF to identify high reliability forward links and use dynamic retransmission thresholding for error control and observe an improvement in convergecast routing over ETX. This is qu...

• Type: Conference
• Year: 2007
• Where: MOBIHOC
• Authors: Lifeng Sang, Anish Arora, Hongwei Zhang
• Keywords: Asymmetric Links, Link Metric Etf, MOBIHOC 2007, One-way Link Estimation, Wireless Networks