ORBIT-USER: Setting up Topologies

[Ivan Seskar]

Hi Reza,

I will let others respond to your particular topology question, but just
want to comment on the possibility of triggering carrier sense with
noise injection: it is certainly possible to increase noise level to a
point of triggering energy detection threshold (mode 1) in the cards
(especially for the nodes that are in the vicinity of injection
antennas). 

Regards,

Ivan.

PS; In addition to noise levels, you should also take into consideration
transmit power and CS threshold as knobs that can be used for topology
creation.

-----Original Message-----
From: owner-orbit-user at winlab.rutgers.edu
[mailto:owner-orbit-user at winlab.rutgers.edu] On Behalf Of Reza Lotun
Sent: Friday, August 24, 2007 5:16 PM
To: orbit-user at winlab.rutgers.edu
Subject: ORBIT-USER: Setting up Topologies

Hello,

I'd like to pose a general question to the list. Has anyone attempted
(and successfully) deployed arbitrary topologies on the grid.

A clarification. According to the orbit wiki, the Orbit approach to
creating arbitrary (multi-hop) topologies is to use noise injection:
http://www.orbit-lab.org/wiki/HowTo/UseNoise
As far as I can see, the idea is to inject constant background white
gaussian noise to raise the noise level, so that only more powerful
signals can be discerned.

I'm interested in simulating a real wireless network deployed in a large
space operating in convential infrastructure mode - this means that some
nodes will naturally be out of range of one another. Is there ever a
danger when injecting noise that the nodes will naturally back-off since
they sense transmission? Is anyone using orbit to test non-mesh-like
802.11 topologies, that is, the tree topology of
client->access_point common to infrastructure networks?

Thanks!
Reza