Asynchronous low power listening has been implemented in Crossbow's MoteWorks, using tinyOS1.x syntax.
For more information, please see: http://www.xbow.com/Products/productdetails.aspx?sid=154 Ning On 2/20/07, Jiakang Lu <[EMAIL PROTECTED]> wrote:
Hi all, Is there any module that implements this CC2420 LPL strategy on Tinyos-1.x? Have anyone written such a radio stack? Thanks. Jiakang David Moss wrote: > Asynchronous low power listening similar to the behavior of B-MAC has been > introduced for the CC2420 radio in TinyOS 2.x. This LPL CC2420 stack is not > B-MAC or X-MAC, by the way. The 'experimental' version is still located in > tos/chips/cc2420_lpl, but a more reliable and robust version can be found in > tinyos-2.x-contrib/rincon/tos/chips/cc2420_lpl. That version is going to > get a few more features before getting put back into the baseline. > > The CC2420 LPL strategy is to use clear channel assessments to determine if > a transmitter is nearby and modulating the channel. If modulation is > detected with valid 802.15.4 data, the radio is left on for a brief moment > to attempt to capture a packet. If a packet is received successfully, the > radio is left on as long as communications are taking place. After a few > moments of inactivity, the radio will continue to duty cycle. > > There isn't much literature on the design of the CC2420 radio stack. Maybe > I'll put something together sometime. Basically it's a standard radio stack > though: A bunch of layers down the send branch, a bunch of layers up the > receive branch, and a bunch of layers to control power. Some layers can be > added and removed from the stack as needed. > > The main reason LPL was not implemented for a long time was because it was > impossible to implement B-MAC on the 2420 radio - specifically, the radio > could not extend its preamble for a long duration of time. A new strategy > had to be developed, and there were many people involved with evolving the > CCA receive check strategy. > > Moteiv's Boomerang features time sychronized CC2420 radio duty cycling, > which is much more efficient than the current asynchronous CC2420 duty > cycling. > > -David > > > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Antonis > Lambrou > Sent: Monday, February 12, 2007 10:27 AM > To: [email protected] > Subject: [Tinyos-help] CC2420 radio stack > > > I am currently conducting research for MAC protocols designed for Wireless > Sensor Networks and I would appreciate some guidance from tinyos-help. > > In your FAQ you have the following answer for the MAC design: > > "Support for the CC2420 radio was introduced in TinyOS 1.1.7. The CC2420 > uses B-MAC. However, the CC2420 radio does not have the Low Power Listening > functionality; it does have the MacControl and MacBackoff interfaces but, > again, the underlying functionality is not implemented." > > If Low Power Listening is not implemented does that mean that the radio is > listening constantly for incoming packets? What are the reasons for not > implementing LPL on the CC2420 radio stack? > > Where can I find more documentation on the design for the CC2420 radio stack > on TinyOS? I have read so far the paper "Versatile Low Power Media Access > for Wireless Sensor Networks", which describes the B-MAC protocol, but as I > understand the protocol is slightly changed on the CC2420 radio stack. > > Thank you, > > [EMAIL PROTECTED] > > > > _______________________________________________ > Tinyos-help mailing list > [email protected] > https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help > > > _______________________________________________ > Tinyos-help mailing list > [email protected] > https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help > _______________________________________________ Tinyos-help mailing list [email protected] https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
_______________________________________________ Tinyos-help mailing list [email protected] https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
