GNU Radio USRP Based MAC Implementation

There has been extensive research on MAC implementation on USRP using
GNU
Radio.

I found few solutions like:-

1.Using CLICK platform to have hybrid PHY MAC layer.

2.FPGA based MAC to remove jitters and delays while host PC and USRP
comunication.

I want to implement Cognitive Radio Network and have been designing own
modified CSMA for MAC implementation.

Should I implement it using GNU Radio /USRP or I should go for some
changes
to insure proper working.

What are the major design constraints?

Are there some working opensource implementation I can check out for and
concentrate more on algorithms rather engineering constraints?

Jay Prakash
Senior Undergraduate
Electronics Engineering
IIT (BHU)
VARANASI

+91-9559475258