Link Metrics

Links in wireless networks are exposed to many external interferences, e.g., weather conditions, higher attenuation than in wired networks, or noise. The quality of the links is therefore changing over time. Routing protocols cannot simply base their routing decisions on the network topology and apply a shortest path routing approach. If the nodes are mobile or there are other moving objects, the topology is additionally constantly changing.

Several advanced routing/path/link metrics have been proposed that consider the quality of links, the available bandwidth, and/or congestion in the network: ETX, ETT, WCETT, etc. Our routing protocols implemented on the DES-SERT routing framework currently provide hop count and ETX as metrics with some other variants of them. An implementation of further metrics and a performance study is required.

Objectives

• Get familar with our routing protocol implementation
• Read literature about link metrics and summarize the current state
• Run some inital simple experiments to get an understanding of the DES-Testbed
• Measure the link quality in the testbed and evaluate your data
• Implement further metrics
• Run an experiement series
• Evaluate your study