The capability of the OFDM PHY implementation to operate in
the three U-NII bands. Coded as an integer value of a three bit
fields as follow:
bit 0 .. capable of operating in the lower (5.15-5.25 GHz)
U-NII band.
bit 1 .. capable of operating in the middle (5.25-5.35 GHz)
U-NII band.
bit 2 .. capable of operating in the middle (5.725-5.825 GHz)
U-NII band.
For example, for an implementation capable of operating in the
lower and middle bands, this attribute would take the value 3.