Sensor Positionning using Spring Relaxation Algorithm (Oct. 2011)
Experimentations conducted on SensLab platforms. Here, the Spring Relaxation Algorithm (SRA) is based on Received Signal Strength Indicator (RSSI). Using RSSI as a distance metric involves errors in the measured values, resulting path-loss, fading, and shadowing effects. We underline the intrinsic limitations of RSSI as a distance metric, in terms of accuracy and stability. Contrary to what we assumed, collaborative localization protocol based on Spring-Relaxation algorithm can not smooth the distance-estimation errors obtained with RSSI measurements. The animation provided below presents a comparison between SRA based on close-to-real distance (left side) and SRA based on RSSI (right side).Video is available here:
- Sensor Positionning using Spring Relaxation Algorithm (real distance VS RSSI)
Dijkstra Self-Stabilizing Token Ring on WSN (March 2011)
We deployed the famous self-stabilizing token ring algorithm, described by Edsger Dijkstra in 1974, on 9 WSN430 sensors. Each node forwards the packet through the ring (the red or green led switchs on when a packet is received).Video is available here:
- Self-stabilazing Token Ring (Dijkstra, 1974)
Materials