The invention relates generally to communication systems and in particular to radio frequency (RF) architectures. Some embodiments of the invention are directed towards a multi-channel inter-BS communication system. The multi-channel inter-BS communication system includes a plurality of co-existing wireless regional area network (WRAN) cells, wherein each of the plurality of co-existing WRAN cells includes a plurality of data frames and at the end of each of the plurality of data frames is a slotted co-existence window. Additional embodiments of the invention include CB frames, fixed-slot host scheduling and modulo scheduling.