Hi~ I am confusing about CSMA using in TinyOs 1.x with iMote2 I tried to modify the application within the TinyOs 1.x 1.CntToLedsAndRfm 2.RfmToLeds
I made my own app with combine 1 and 2 so my app can transmit and receive. My experiment: 1.Using 3 iMote2 to send packets (only using timer to change sending rate). 2.Using 1 iMote2 to receive packets and using iMoteConsole with trace function to print the debug message. Question: When I set all the 3 send nodes at same rate (ex. 20 packets/sec)(timer=50ms) The receiver can receive all the packets without drop. (I tried to observe the packet's sequence no. at receiver) "But" when I tried to using different rate (ex.18,20,22 packets/sec) Some packet will just lost, is that cause by collision? The TinyOs 1.x with CC2420 stack should has CCA enable as default, can CCA prevent this kind packet loss? Or it is not cause by collision? other reason? Hope any expert can help me out. PS:There is no sync. process involved in the experiment. 3 send nodes also turn on randomly.(manually) (turn on means the switch on the battery pack for iMote2) Thank you Henry
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