Thanks a lot Paul. That was really helpful and I now have a place to start.
I am implementing some routing ideas in an application similar to SoundLocalize and needed for this. Can you also guide me with ReadStream and MicStream interfaces which might be more suited to my application since I need to actually deal with buffers and a set of values rather than just 1 ? please let me know if you would be willing to help me since I have been posting many queries on this forum for the past few days but have not heard back much. Thanks a lot once again. I really appreciate your help. Sincerely Akankshu Dhawan On Tue, Nov 10, 2009 at 10:54 PM, Paul Johnson <[email protected]> wrote: > Akankshu, > > It really depends on a lot of factors. An environment with lots of > obstacles(trees, cubicles, buildings, cars, etc) can cause severe multipath > effects which make estimation difficult. But as a start, you can look at > free space propagation loss models. These will give you a *minimum* loss > that any omnidirectional signal will experience as it travels through free > space (no obstacles near transmitter, receiver, or anywhere inbetween). > There are more complicated models that you can look into but that would > probably be my first start. The general principle of Free Space Propagation > is that each time the distance doubles (goes from 1 meter to 2, 2 to 4, 4 to > 8, etc) the signal experiences a 3dB loss. This means that Received Signal > Strength (RSS) rapidly decrease as you first begin to move away from a > transmitter, then decrease more slowly as you get further and further away. > The signal strength loss between 1 meter and 2 meters is (approximately) the > same as the signal strength loss between 200 meters and 400 meters. > > As for reliable reception, that depends on a lot of factors too (noise, > multipath signals arriving out of phase and at differing power levels, > etc). In a perfect world, as long as the RSS is above the radio > sensitivity, then you should be able to correctly detect and decode the > packet, but in reality, noise, interference and multipath effects lower the > effective sensitivity of the radio because it makes it harder to decode the > signal from the noisy environment. > > Mathematical models can give you a basis to start your tests, but are never > going to be a replacement for actual experiments. Slight differences in > hardware between motes can also play a role in the transmission range. Hope > this helps. > > -Paul > > Akankshu Dhawan wrote: > > Hi All > I know we can set the transmission power levels of different motes. I want > to know what is the correlation factor between the transmission power level > and distance that it can reliably propagate ? > > I am using MICAZ motes and MTS310 sensorboard. > > Thanks > Akankshu > > -- > First they ignore you, then they laugh at you, then they fight you, then > you win. > - Mahatma Gandhi > > ------------------------------ > > _______________________________________________ > Tinyos-help mailing > [email protected]https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help > > > -- First they ignore you, then they laugh at you, then they fight you, then you win. - Mahatma Gandhi
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