How to increase transmit output power density?

Hello decawavers,
I have question about how can we create a design with DW1000 whose tranmitter output power density will violate the UWB regulation level (-41.3 dBm\Mhz) and will increase approximately minus twenties (-21 dBm\Mhz) level ?
Actually, I have some confused.
-What is the reason of Using Smart Transmit Power Control? Can we get desired level (-21 dBm\Mhz) by only changing the control register values?
-Should we add some external circuit such that power amlifier?
All in all, my problem is that how I can get transmitter output power density in level of -21 dBm\Mhz? by manipulating control register of the module OR adding some external circutry?