[ns] Two Q's of mac simulation on wireless network

["Paul Q.Xu" <qingxu@newton.me.berkeley.edu>]

Hi, everyone,
	I am working on simulation of of wireless network with ns-2 and I have 
two questions.

	1)I hope to simulate a MAC protocol which is the same as 802.11 
except that it does not do carrier sense, i.e. every agent sends the 
message as soon as the message is generated. How can I disable the CS 
part of the mac802_11.cc? 

	2)In the next step I would simulate another MAC protocol which is 
the same as the above one but it intentionally retransmits the message 
three times. The time slots to transmit is uniformly distributed btween 
the instant the message is generated and 50 ms after. The reason of the 
retransmission is to avoid collision, and I hope to find the optimal 
number of rettransmissions. Is there any way I can modify the 
mac802_11.cc to achieve it?

	Thanks a lot.

Qing Xu