iETT: A Quality Routing Metric for Multi-Rate Multi-Hop Networks

Routing metrics are critical to select a path that yields a high throughput in multi-rate multi-hop wireless networks. This paper illustrates the weaknesses of existing routing metrics and proposes a new routing metric called Improved Expected Transmission Time (iETT). iETT addresses two key characteristics of a routing path that other routing metrics ignored: 1) a high discrepancy in packet loss rates of links and 2) the position of the links with different packet loss rates. By capturing these two characteristics, the iETT metric is able to choose a route with a better performance than shortest path, Expected Transmission Count (ETX) and Expected Transmission Time (ETT) metrics.