CAMPUS — Cognitive access of media with power control for unlicensed users through switching

This paper proposes a cognitive access of media with power control for unlicensed users through switching (CAMPUS), a scheme to overcome spectrum scarcity and to allow secondary users (SUs) to access a channel when coexisting with primary users (PUs). CAMPUS is a novel hybridization of interweave and underlay transmissions for spectrum access and management. Under this scheme, SUs sense the operating channels and the coverage range of access point (AP) in primary unlicensed network IEEE 802.11 and switch on unoccupied, non-overlapping spectrum, in order to avoid interference with primary users. If the channel is not available or gets occupied while SU is in communication, the conversation is completed with power controlled transmission, such that SU and PU signals do not interfere. CAMPUS in an alternative to the basic IEEE 802.11b protocol, where SU signal does not cause disruption to PU network and is designed to support continuous transmission to its intended destination. A region of restricted operation is also found, in case PU occupies all the channels of the considered band and the SU exist on the overlapping boundaries.