Hi all,
Can anybody tell me if there is some relation between the link quality indiactor (LQI) and the probability of packet loss, between two motes? Or is there some method to find out the relation?
Thanks,
Venkat.___
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Tinyos-
Yes, there is *some* relation: they're positively correlated. But on
the CC2420 radio, LQI shows significant variance for a given packet
reception rate (PRR). You may be much better off using RSSI, which
shows far less variance for a given PRR.
You can use (logistic) regression to determine the
There is a graph that shows a dependence between distance and PRR,
LQI, and RSSI in the paper about Telos design (figure 5 in
http://www.polastre.com/papers/spots05-telos.pdf)
While it does not actually show the regression, and distance is made
explicit, it should at least give you a flavor of wha
The Telos graphs are nice in that they show the relationship between
some of these variables but some mental gymnastics are required to
make the leap from what's shown to PRR vs RSSI and PRR vs LQI. And,
given the variances involved, I'm not sure that everyone would come to
the same conclusion.
You're correct that the distance is just introducing confusion into
this discussion, it would have been much better to do plots of PPR v
LQi and PPR v. RSSI.
I would disagree however with your characterization that RSSI has a
better correlation with PPR (and you have not presented any actual
data
Actually, Rob, I think we're both right (and wrong). If you look at
the Telos data, RSSI shows much lower variance and much greater range
for short distances whereas LQI shows comparable variance but greater
range for medium and longer distances. If distance approximates PRR,
then RSSI would be
On 5/9/06, Prabal Dutta <[EMAIL PROTECTED]> wrote:
Actually, Rob, I think we're both right (and wrong). If you look at
the Telos data, RSSI shows much lower variance and much greater range
for short distances whereas LQI shows comparable variance but greater
range for medium and longer distances
TED]>Sent: Wednesday, May 10, 2006 2:19:59 AMSubject: Re: [Tinyos-help] LQI and probability of packet loss
Hi Venkat,We don't have a good equation and I'm not sure that it will be thatsimple because of the variances involved (these measures are allstatistical). Instead, what seems more
