We have a question on monitoring of environment by reading RSSI values
continuously from RSSI register. We ran an experiment, where two nodes
exchange messages between them and continuously read the RSSI values from
both the received packet and RSSI register. We could not observe any change
in RSSI values, when there is packet loss between motes. Sometimes, there
was not much variation in the RSSI values, but still there was some
packet-loss.
RSSI Values obtained by us are like this:

-99,-99,-99,-99,-98,-65,-56,-86,-99,-99,-98..........

According to our understanding, as the sensitivity threshold of CC2420 radio
is -95dBm, mote should lose packets, if the RSSI is less than -95dBm ( i.e,
-96dBm,-97dBm,...........). But, in reality though the RSSI values are less
than the -95dBm, packets are being received by the receiver successfully and
sometimes though the RSSI value is something like -76dBm, the packets are
getting lost. We couldnot understand why the RSSI register values are less
than -95dBm even when we are receiving packets?

Any suggestions on how to estimate the channel quality using the RSSI
values?


Thanks--
Madhu,
Trisul

On 2/9/07, Philip Levis <[EMAIL PROTECTED]> wrote:

On Feb 8, 2007, at 2:09 PM, Joe Polastre wrote:

> In 5.1, which manufacturer(s) provided the nodes in the testbed?
> Mixing nodes from different manufacturers (ie, Berkeley Telos, Moteiv
> Tmote Sky, and/or TelosB clones from others) can be the cause of the
> "stray" node.

Those are all Berkeley TelosB nodes; they are the Omega testbed.

Section 6.1 reports the variations across the mirage testbed of micaz
nodes.

We have data for telosb's from a variety of manufacturers (moteiv,
crossbow, berkeley, etc.); I'll ask the student involved to take a
look at the moteiv numbers.

Phil
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--
Madhu Mudigonda
Research Assistant,
SE-Lab,Fenn College, CSU.
Ph.# 216-856-0127
Fax.#: 360-233-0127
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