Congestion vs Channel losses

Hi,

I have few questions for you regarding optimizing TCP over wireless 
interface. I go through most of the documents posted on the IPLC 
working group web site (high speed scan). 

My first question is: TCP assume channel losses ~zero. 
Is this assumption is correct.

My second question is: Is any working group in IETF or other reseach 
group addresses congestion vs channel losses issue related to TCP.

My third question is: I think ECN addresses the congestion 
problem not channel losses: Is this assumption is correct.

Thanks,
Amin.