[Tinyos-help] asymmetric links

[Eli Katsiri]

Dear all,

I am running some tests trying to simulate "hidden nodes" or "asymmetric
links". Are there any rules that determine when a node is hidden from
another node, under TOSSIM (tinyos 2.x) radio model? For example, is it the
case that a link is hidden from another if their gains differ more than a
fixed constant, or if the absolute value of the gain is bigger or smaller
than a constant?

I thought that all nodes with gain bigger than -77dBM(CCA threshold value)
would be out of range of the source node.

For example, for the topology

0 1 -83
1 0 -85

I thought that 0 would not hear 1 and vice versa. However, in my results, I
have been able to exchange communication packets between them!
Also, if one node had very big gain, and the other node has a reasonably
small one, they seem to be both out of range from each other!

Are there some equations that I can use to calculate the asymmetric links,
or a node's range given their gains?

Many thanks,
Eli


-- 
Dr. Eleftheria Katsiri
Lecturer in Computer Science
Birkbeck College,
University of London
office: +44 (0) 207 631 6862
email: ekatsiri at cantab.net
web: www.dcs.bbk.ac.uk/~eli <http://www.dcs.bbk.ac.uk/%7Eeli>



-- 
Dr. Eleftheria Katsiri
Lecturer in Computer Science
Birkbeck College,
University of London
office: +44 (0) 207 631 6862
email: ekatsiri at cantab.net
web: www.dcs.bbk.ac.uk/~eli <http://www.dcs.bbk.ac.uk/%7Eeli>



-- 
Dr. Eleftheria Katsiri
Lecturer in Computer Science
Birkbeck College,
University of London
office: +44 (0) 207 631 6862
email: ekatsiri at cantab.net
web: www.dcs.bbk.ac.uk/~eli
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