Link quality ranking: Getting the best out of unreliable links

Link quality estimation has been an active area of research within the wireless sensor network community. It is now well known that the estimation of reliable links requires few sample packets - less than 10, while the estimation of unreliable links require many more - above 50. In scenarios where unreliable links are ubiquitous, and a rapid transfer of data is needed, traditional estimation techniques are not a viable option. In such scenarios, it is instead sufficient to identify the best link available at any given time. Within this context, we propose Link Quality Ranking (LQR), a mechanism that identifies the best link available when only unreliable links are present. Our testbed results indicate that with one sample packet, the delivery rate of LQR - with respect to the best link available - is above 93%. With 10 sample packets, the performance is above 96%.