The SP implemented by Dr. Polastre support 802.15.4. Each node is a coordinator and send Beacon message. I think it works well for low power listening by synchronizing nodes in the network. Especially, every node will send beacon message with its schedule; others can receive the message and synchronize with it.
Regards, Hui On 8/8/2006, "[EMAIL PROTECTED]" <[EMAIL PROTECTED]> wrote: > >Yes I am also concerned about slotted ACKs. > >Section 5.2 considers the fact that it is not neccesary to fire a timer >every 20 symbols and proposes Adaptive Timer Resolution mechanism. but >later it quotes proposed mechanism could not solve the starvation problem >at the data rate of 2 frames/sec. > >As paper title gives a view that TinyOS concepts is the limitation for >supporting beacon mode. But I think the real bottleneck is hardware (MCU) >capabilities itself. I am also trying understand how any other modren >operating system with preemptive scheduling (for ex. t-kernel) can handle >the situation. > >Thanking you, >D. Manjunath > >On Tue, 8 Aug 2006, [iso-8859-1] Diego Bartolom� Arquillo wrote: > >> Hi all, >> I am agree with Phil about the section 5.1 of the paper. It is not neccesary >> to fire a timer every 20 symbols. I think the statement: "In order to >> communicate in a beacon-enabled network, a timer expiring every 20 symbols, >> i.e. 320 us, is needed" is not correct. The only real problem that I see, >> could be the related in section 5.3. If it is true that the transmission of >> an acknowledgment from software require 132 symbols, it will not be possible >> to carry out the timing requirements for slotted acknowledgments. >> BR, >> Diego >> >> -----Mensaje original----- >> De: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] En nombre de Philip Levis >> Enviado el: martes, 08 de agosto de 2006 0:00 >> Para: [EMAIL PROTECTED] >> CC: [email protected] >> Asunto: Re: [Tinyos-help] Re: IEEE-802.15.4 - Beacon Mode >> >> On Aug 5, 2006, at 4:30 AM, [EMAIL PROTECTED] wrote: >> >> > >> > Dear friends, >> > >> > The paper entitled "EVALUATING THE USE OF MOTES AND TINYOS FOR >> > A MOBILE SENSOR PLATFORM" >> > evaluates 802.15.4 (beaconmode) on a real sensor network of micaz and >> > telos motes. >> > Suprisingly, it says beacon mode can not be supported on >> > capabilities that present motes posses. Any comments on the paper >> > will be very useful....... >> > >> > please google for the paper as attachment mails are bouncing back!!!! >> >> I'm not sure if I understand all of the conclusions made in the paper; among >> other things, Jonathan Hui and Joe Polastre implemented >> 802.15.4 beaconing mode as part of the implementation of SP. >> >> For example, in section 5.1 you state that 15.4 requires a periodic 20 >> symbol timer, and that this makes it impossible to implement properly. I >> don't think your statement is correct. It requires a timer with a fidelity >> of 1 symbol, but there's nothing there that means that you need to fire a >> timer every 20 symbols... why would you need to do so? You're picking a >> random number in the range of random >> (2^(BE-1)) unit periods... >> >> Phil >> _______________________________________________ >> Tinyos-help mailing list >> [email protected] >> https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help >> >> >> >> -- >> This message has been scanned for viruses and >> dangerous content by MailScanner, and is >> believed to be clean. >> >> > >-- >This message has been scanned for viruses and >dangerous content by MailScanner, and is >believed to be clean. > > >_______________________________________________ >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
