Sec.  27.1220   Transmission standards.

   The width of a channel in the LBS and UBS is 5.5 MHz, with the exception of
   BRS channels 1 and 2 which are 6.0 MHz. The width of all channels in the MBS
   is 6 MHz. However, the licensee may subchannelize its authorized bandwidth,
   provided that digital modulation is employed and the aggregate power does
   not exceed the authorized power for the channel. The licensee may also,
   jointly with other licensees, transmit utilizing bandwidth in excess of its
   authorized bandwidth, provided that digital modulation is employed, all
   power spectral density requirements set forth in this part are met and the
   out-of-band emissions restrictions set forth in  Sec. 27.53 are met at the edges
   of the channels employed.