In TinyOS 2.0.1 the Ack LPL version should not stop sending its wake-up transmission to the broadcast address, ensuring all nodes in the vicinity receive the broadcast packet. The LPL layer, when sending to the broadcast address, disables acknowledgement requests and shouldn't even check acknowledgements on its internal sendDone() events.
Preambles, or more aptly named "wake-up transmissions" are packetized (there's nothing preamble about it). In the TinyOS 2.0.1 "Ack" version, on the other hand, will simply transmit the packet it is trying to actually deliver. If acknowledged right away, it stops. In this sense it's just transmitting at 100% throughput. The "NoAck" LPL version will initiate another full wake-up transmission lasting the duration of a receive check. You're correct in assuming that a more efficient method for the "NoAck" version is for it to realize that because it just delivered a packet to a node, it should send the next packet with no packetized wake-up transmission. I'll ensure this gets documented. -David -----Original Message----- From: Murray, Ben [mailto:[EMAIL PROTECTED] Sent: Wednesday, October 31, 2007 1:44 AM To: 'David Moss'; Murray, Ben; 'Tinyos help Forum (E-mail)' Subject: RE: [Tinyos-help] successive messages in LPL - do they use the preamble or do they not need to? Will/Should the second send initiate a second preamble within LPL or will/should LPL decide to send the message straight away (can't really use the ACK'd LPL as a number of the messages are basically broadcast so if I ACK then I run the risk of only the node that ACK'd receiving properly if the rest wake at different times). Ideally it would realise it had recently (or recently-enough) performed a long preamble so could just start transmitting straight away? thanks for the replies! -Ben > -----Original Message----- > From: David Moss [mailto:[EMAIL PROTECTED] > Sent: 30 October 2007 19:25 > To: 'Murray, Ben'; 'Tinyos help Forum (E-mail)' > Subject: RE: [Tinyos-help] successive messages in LPL - do > they use the > preamble or do they not need to? > > > If you get a sendDone() event and call your next send() event quickly > (within tens of milliseconds) then both radios will still be > awake and you > will be communicating at 100% throughput. Both radios will > remain active as > long as there is useful communication taking place. In this manner, > multiple packets will be received during the same wake-up period. > > -David > > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On > Behalf Of Murray, > Ben > Sent: Tuesday, October 30, 2007 10:48 AM > To: Tinyos help Forum (E-mail) > Subject: [Tinyos-help] successive messages in LPL - do they > use the preamble > or do they not need to? > > [tos2, micaz] > > When using low power listening if I wish to send two packets > over the radio, > it is there a special way in which I can make sure they will > both be sent > after the same preamble such that all receiving motes that > caught preamble > in front of the first message also received the subsequent > second message > before they go to sleep again on will LPL/TOS take care of > this internally? > > i.e. if my code look something like this: > setRxSleepInterval(500) > send(pkt1) --> senddone (confirming send accepted for pkt1) > send(pkt2) (does this have to wait for the senddone from pkt1 > or will it be > put in a queue? > > Will a LPL node that wakes during the preamble receive both > pkt1 and pkt2 > during the same transmission in quick succession for (or at > least during te > same wake period) > > Many Thanks > Ben > > > > ************************************************************** > ************** > *** > Please consider the environment before printing this email. > ************************************************************** > ************** > *** > This email and any files transmitted with it are intended > solely for the use > of > the individual or entity to whom they are addressed and may > not be divulged > to > any third party without the express permission of the > originator. Any views > expressed in this message are those of the individual sender, > except where > the > sender specifically states them to be the views of Thales Research & > Technology > (UK) Limited. > ************************************************************** > ************** > *** > > _______________________________________________ > Tinyos-help mailing list > [email protected] > https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/t inyos-help _______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
