DCF and PCF

[calafate]

Hi,

I have some doubts concerning PCF and DCF:

-Can an AP not implement PCF?
-In the CP, stations associated with the AP still have to forward all packets through it or can they send it directly to destination (as in ad-hoc mode)?
-Can the AP transmit in the CP using DCF?
-If a station is in ad-hoc mode but has an Ethernet card and is therefore used as an Internet gateway, the BSS therefore formed is and Independent BSS, Infrastructure BSS or what?

Thanks for the help,

Carlos Calafate
UPV, Spain