Hi all, I have two questions about TinyOS CSMA backoff and low power listening strategies. (1) In CC2420.h, the units of back-off are defined as 10 jiffies (32kHz ticks). The initial back-off is 1-32 back-off units (300us - 10ms); the congestion back-off is 1-8 back-off (300us-2.5ms). Am I right? If congestions happen many times, what is the strategy to handle that situation? Is there a maximum times for doinging CCA or it will continue will finally get the clear channel?
(2) In DefaultLpl.h, a default parameter "MAX_LPL_CCA_CHECKS" is set to 400, I don't quite understand what is the reason for setting this number? Why It has to detect the channel 400 times before making the desision that no signal is on the air? The time of doing 400 times checks is about 50ms, is it set to cover the the maximum gap between two consecutive sending packet action, which is caused by radio backoff ? I am a little confused here. Thank you,
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