[Smac-users] questions about SMAC simulation

[he lee]

Hi everyone:

I am now trying to simulate S-MAC on OPNET which is another network 
performance simulation tool as NS. Currently, I have two S-MAC documents 
which are used to refere my simulation design. They are "An Energy-Efficient 
MAC protocol for wireless sensor networks" and "Medium access control with 
coordinated adaptive sleeping for wireless sensor networks". The scenario I 
am using now is the two hop (5 nodes) topology.

For the same topology, I have found that the simulation parameters are 
different in the two papers. But the result curves are the same. Is there 
anyone coud please help me out? I have been in the following problems for 
more than a month.

(1) could anyone give me the following parameters:

     (a) packet size for  RTS, CTS, DATA, ACK and SYNC (includes 
pre_symoble+header+CRC)
     (b) the data rate and duty_cycle
     (c) the length of DIFS, SIFS and SLOTtime
(2) When a node is in DIFS time waiting before a RTS packet transmission, if 
the channel becomes busy, how is the node will be? In 802.11 the node will 
go to defer process and keep on monitoring the channel stat. I think in 
S-MAC to reserve energy the node should go to free stat to receive the 
packet which causes the interrupt. Then it can use the duration information 
in the received packet to set its NAV to go to sleep untill the end of 
current packet exchange process. am I right?
(3) After a successful packet transmission, does the transmittor or receiver 
need to go to backoff process to content the channel for further packert 
transmission?

Thanks

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