ctions enable home BS or femto-cells and plug- and-play form of operation for indoor BS (i.e., Multi-carrier functions enable control and operation of a number of adjacent or non-adjacent RF carriers (i.e., virtual wideband operation) where the RF carriers can be assigned to unicast and/ or multicast and broadcast services. A single MAC instantiation will be used to control several physical layers. The mobile terminal is not required to support multi-carrier operation. However, if it does support multi-carrier operation, it may receive control and signaling, broadcast, and synchronization channels through a primary carrier and traffic assignments (or services) via the secondary carriers. xi "Femto-cells are low-power wireless access points that operate in licensed spectrum to connect standard mobile devices to a mobile operator's network using residential DSL or cable broadband connections [25,26]. 3.2 The IEEE 802. 16m protocol structure IEEE 802.16m Air Interface Multi-Radio Device Radio i Radio i Radio j Radio j 802.16m Access Point Device Device Access Point inter-radio interface FIGURE 3-13 A generic multi-radio coexistence model [12] Multi-radio coexistence functions in IEEE 802.16m enable the MS to generate MAC management messages in order to report information on its collocated radio activities, and enable the BS to generate MAC management messages to respond with the appropriate actions to support multi-radio coexistence operation. Furthermore, the multi-radio coexistence functional block at the BS communicates with the scheduler functional block to assist proper scheduling of the MS according to the reported collocated coexistence activities. The multi- radio coexistence function is independent of the sleep mode operation to enable optimal power efficiency with a high level of coexistence support. However, when sleep mode provides sufficient collocated coexistence support, the multi-radio coexistence function may not be used (see Figure 3-13). Interference management functions are used to manage the int