Dear All, We are not able to figure out a reason why ETX values in CTP increases as wake-up interval of the LPL (BoXMaC-One) increases. We have a simple setup of a sender and a root node placed adjacent to each other. Nodes use maximum power of 0 dBm.
1) We are using IPI of 15s. We repeated the experiment at three different places with sevral runs runs at every location. Different wake-up intervals were tried back-to-back so that temporal variations are minimized. We used wake-up intervals of 10, 20, 40, 100, and 1000 (ms). 2) We also used "LPL.setRemoteWakeupInterval(&packet, WAKEUP_INTERVAL + 100)" but without any luck. 3) Our debug messages show that CTP's RetxmitTimer being fired quite a few times before sucessfully transmitting every packet. 4) I first thought that the loss of data packets in the BoXMAC's preamble could be the reason, but looking into the LPL code, I understand that preamble packet losses are not fed into the Link Estimator. 5) In some experimental runs, particularly when the wake-up interval is 1000ms, no packet go-through. Requires a hard reboot. 6) Searching the archieves for "CTP and LPL on tmote", I found that similar problem being discussed sometime in Dec 2008. The discussion suggests quite a few number of changes. http://mail.millennium.berkeley.edu/pipermail/tinyos-devel/2008-December/003510.html BTW, we are using the latest checkout from googlecode. Thanking you, D. Manjunath ################################################################################################################ *************************************************************************************************************** _______________________________________________ Tinyos-help mailing list Tinyos-help@millennium.berkeley.edu https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
