[Likely SPAM] Re: [Tinyos-help] CC2420 radio stack

[Ning Xu]

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 <jl9jb at cs.virginia.edu> 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: tinyos-help-bounces at Millennium.Berkeley.EDU
> > [mailto:tinyos-help-bounces at Millennium.Berkeley.EDU] On Behalf Of Antonis
> > Lambrou
> > Sent: Monday, February 12, 2007 10:27 AM
> > To: tinyos-help at Millennium.Berkeley.EDU
> > 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,
> >
> > Antonis.Lambrou at ncl.ac.uk
> >
> >
> >
> > _______________________________________________
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> > Tinyos-help at Millennium.Berkeley.EDU
> > https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
> >
> >
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> >
>
>
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