  Future broadband networks need to provide high capacity at low cost with
increased revenue through enhanced services. WiMAX came up as one of the
leading technologies, however, the 2.3 GHz and 2.5 GHz frequency bands
allocated create two serious coexistence issues with the adjacent 2.4 GHz ISM
band. First problem is to address radio interfaces that are located on two
independent platforms and still possess the potential for mutual interference
owing to close proximity to each other. The Adaptive Frame Reservation Scheme
presented here extends the CTS frame reservation signaling defined in 802.11
specifications to a demand based and adaptive scheme. Second issue is to
address the coexistence problem in multi-radio platforms where two or more
radios are co-located, creating an even worse interference scenario. This can
be managed by hardware signaling that can be made available between radio
interfaces through OS control. The development of a smart Co-located
Coexistence Controller is explored which continuously receives transmission,
reception and sleep requests from attached interfaces and in return grant
permissions.
