Is it possible to fit modulation/demodulation, error handling and MAC protocol stuff on FPGA?

Hi all
I’m doing the project on USRP, a digital data transmission system. I use
RFX2400
daughterboard. I want to implement something like 802.11b/g system, but
I would like to put all the modulation/demodulation work, error
detection/correction and MAC protocol on FPGA, in order to make the
system independent from PC. I will feed a data stream to the USRP and
want to use the fastest rate possible, and I want the receiver to send
only some sort of acknowledgement for the received packets (cumulative
acks may be considered). The first question is, is it possible to fit
such a program on USRP’s Cyclone? As I understand, existing code takes
almost all the space on FPGA, but it’s possible to remove unused parts
(for ex., I don’t need all the channels) and free some space. Another
question is which modulation technique will take least space while
doing the job (i need at least 25 meters range)? And I also wonder if
the multipath propagation will be a big problem? If yes, is there an
easy way to deal with it?
Any help will be appreciated! Thanx in advance for your answer

Andrey Brandis