This project is part of Berkeley WEBS: Wireless Embedded Systems

NEST Weekly Updates
May 5, 2002

Phil Levis
I have implemented the first half of a reliable transport mechanism --
using  link-level retransmissions and implicit acknowledgements to deliver
a packet to the base station with improved reliability over single
transmission routing. I'm halfway finished with the end-to-end explicit
acknowledgement; after that is completed, I will add some simple routing
tree heuristics.

It is imperative that, for this protocol to work, the network  not have a
depth greater than 6; explicit routes are maintained in data packets for
backwards propagation of explicit end-to-end ACKs.
 

Luca Schenato
I used the data from magnetic sensor that Rob collected and I ran a  simple
position estimation algorithm. The results are so and so mainly  because
the sensors are not calibrated and some are dead. I can show some  plots
tomorrow.
 

Kamin Whitehouse
I completed TOF ranging  with simple calibration in the testbed environment, meaning that I can localize the nodes on the 1ft x 1ft grid of the testbed to within about 1.5 inches using centralized calculations. This is done using manual calibration and  assumes some anchor nodes. It requires  each node to chirp only about 5-10 times each, and includes a graphical display. TOF_RANGING component has been started and the ranging protocol has been completed.  To Do: 1)  push the calculations for both ranging and  localization into the mote 2) design a  localization protocol 3)improve the calibration to be robust enough to leave the testbed environment.

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