Hi Stefano, Thank you. I am now clearly understand the situation of the RSSI measurements. Your paper also helps me a lot to the understanding.
Thanks again. Cheers, Yusnaidi On Wed, Jun 16, 2010 at 5:34 PM, Stefano "Kismet" Lenzi <kismet...@gmail.com > wrote: > Hi Yusnaidi, > > The value shown by the Java application are the RSSI value read by the > receiving node, that is a value generated by the radio chip according > to its datasheet. Because the value is calculated by using signal > strength it is influenced by the output power settings of the > transmitting node, but it depends also on many others environment > factors: distance, multi-path, fading, and so on, for further > investigation I would suggest you to look at the paper [1] were > Figure 2 shows how the RSSI changes even if the distance between nodes > do not change. > If you want to convert the value shown by java to the dBm value you > have to look at the datasheet of the radio chip that is used by your > nodes. For example, in case of the IRIS which uses the AT86RF230 radio > the return value should be decrease by 91, thus if the java > application running on an IRIS shows 35 it means that the received > value is -56 dBm. > > Best regards, > Stefano "Kismet" Lenzi > > [1] - http://wnlab.isti.cnr.it/paolo/papers/ICC09-Final.pdf > > On Wed, Jun 16, 2010 at 14:34, Yusnaidi Md Yusof <yusnaid...@gmail.com> > wrote: > > Hi All, > > > > I need a help here. I have gone through the RssiDemo application and able > to > > observe the RSSI value. > > > > Some of the values I got were: -9, -20, -10, 0, etc. I am just wondering > is > > it this value represents the output power value sent by the sending > motes? > > If so, is the value is in dBm format? I have checked with the Output > Power > > Programming settings in the Chipcon CC2420 datasheet (rev 1.2), > 2004-06-09, > > page 50. The table shows the output power settings and typical current > > consumption of the 2.45GHz radio. Some of the values of the Output Power > in > > the table are: 0, -1, -3, -5, -7, -10, -15, and -25. > > > > Thus, are these values represents the similar value I got from the > RssiDemo > > application (I am using the micaz motes)? If not, is there any reference > can > > I refer to translate the equivalent output power (in dBm) from the values > I > > got? > > > > Many thanks in advance for any kind help. > > > > Yusnaidi > > > > _______________________________________________ > > Tinyos-help mailing list > > Tinyos-help@millennium.berkeley.edu > > https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help > > >
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