What is the next generation UWB spec?

[kel8157]

Now I am reading into UWB from Wimedia, the MB-OFDM specs.
What's the next generation after current MB-OFDM? My google didn't give any clue.
Where can I find specifications?
:?:

 

[III]

What papers about WiMedia have U read, can U suggest some of them, perhaps a white paper or a good book.
I'm interested in the field.