[Contiki-developers] ContikiMAC - timing for waiting the ACK

[Ana B. <Ana...@im...>]

Hello,

I would like to ask for a bit of help .

First, in the net/mac/contikimac.c code, the time to wait for the 
potential detected ack is :
#
#define AFTER_ACK_DETECTECT_WAIT_TIME      RTIMER_ARCH_SECOND / 1500 = 0.6ms
#
with the interpacket interval of tow successive packet transmissions :

#define INTER_PACKET_INTERVAL              RTIMER_ARCH_SECOND / 5000 = 
0.2 ms



The logic :

As we have the 802.15.4 framer , the 802.15.4 standard says that an 
ack-wait time  is supposed to be 12 symbols.

t ack_wait_time = 12 symbols
1 symbol = 4/250 ms
so, t ack_wait_time= 0.192 ms

<< Here I am confused. So,why the time inter-packets is smaller than the 
ack-wait time ?


Second, we have the following modes in contikimac : broadcast without 
ack and unicast with ack .
Is is right that  the sender in broadcast mode goes to sleep the time 
between data packets, whereas in unicast mode it stays on until it 
receives the ack?

Thank you in advance.

Regards,
Ana Bildea