Date Added: Dec 2009
Cognitive Radio Networks (CRNs) have recently emerged as a promising technology to improve spectrum utilization by allowing secondary users to dynamically access idle primary channels. As progress is made and computationally powerful wireless devices are proliferated, there is a compelling need of enabling multicast services for secondary users. Thus, it is crucial to design an efficient multicast scheduling protocol in CRNs. However, state-of-the-art multicast scheduling protocols are not well designed for CRNs. First, due to primary channel dynamics and user mobility, there may not exist commonly available channels for secondary users, which inevitably make the multicast scheduling infeasible. Second, the potential benefits provided by user and channel diversities are overlooked, which leads to under-utilization of the scarce wireless bandwidth.