need a help on uwb transmitter design software

hi friends now i'm working with uwb transmitter design.,
with following things
a fully digital txr freq range 3.1 -10.6Ghz
1.low power consumption
2.using gaussian pulses
3.using mcml configuration for delay generation
overall i,am working in cmos transistor level so, please sugges any software to simulate this one...

i'm working wit uwb transmitter design with following things
a fully digital transmitter with mcml configuration for delay
working with cmos transistor level desgin
it have gaussian pulses
need a suitable software for simulation