ORBIT-USER: Radio Reception

[Sanjit Krishnan Kaul]

I have pasted two links below, each corresponding to a rar file, with per
and rssi plots seen on the big grid for 200 or more nodes.

http://www.winlab.rutgers.edu/~sanjit/Documents/per.rar

http://www.winlab.rutgers.edu/~sanjit/Documents/rssi.rar

Rate 1M/ channel 3/ 34 byte mac payload/ 3000 packets transmitted in 3 secs.

The name of a jpg file is Results_<TX>_DailyTest_<date>.jpg.

The jpg file corresponds to the PER observed when TX transmits (no beacons
or any other mgmt frames, all that is suppressed at the transmitter) and all
other nodes receive (in monitor mode). The nodes in white were not a part of
the experiment. The transmitting mode is marked as TX on the plots. For the
RSSI plots the mode of the values received over 3000 transmitted packets is
plotted.

I have not looked into why certain nodes show PER, ideally they shouldn't
(no wireless reasons at least). The measurements were done on July 19.

In my plots 4-8 receives all from 5-11 but shows PER for certain other
transmitters. So it is possible that the node has a problem.

Hope that helps,

Sanjit

-----Original Message-----
From: owner-orbit-user at winlab.rutgers.edu
[mailto:owner-orbit-user at winlab.rutgers.edu] On Behalf Of Haris Kremo
Sent: Monday, August 28, 2006 6:21 PM
To: orbit-user at winlab.rutgers.edu
Subject: Re: ORBIT-USER: Radio Reception

Hi Chris,

Please keep in mind that the nodes are not calibrated, and we are
developing the procedure  these days. In a few weeks we will gradually
remove all nodes, one by one, from the grid and check for sloppy
cards.

In the meantime, I believe Sanjit's got the most experience with RSSI
logging, so he might know about these 2 nodes in particular.

In a few days we should have antenna pattern measurements done
(something we have to do outside Winlab) and that may also help in
regard to your problem.

Assuming you observed this for a single node, my bet is that the
reason is the card on that particular node.

I know this does not help much, but we are working on the issue.

H.

On 8/28/06, chris at orderonenetworks.com <chris at orderonenetworks.com> wrote:
> Hello All,
>
> Has anyone noticed that adjacent radios are much more likely to miss
> packets on the diagonal compared to side by side or up and down?. ie
> node4-8 missing packets from node5-7 orders of magnitude more often then
> from its other neighbors.
>
> I'm noticing this while broadcasting packets in an otherwise quiet
> environment (no beacons, etc).
>
> I need to do a bunch more testing to confirm this, but it could save me
> some time if someone else has already done the work. Or alternatively,
> knows why this might be the case (i.e some radios in the grid don't behave
> really well)
>
> Thanks,
> Chris
>
>