Subcarrier, Bit and Power Allocation for Multiuser OFDM-Based Multi-Cell Cognitive Radio Systems

The authors study the subcarrier, bit and power allocation problem for multiuser OFDM-based multi-cell Cognitive Radio (CR) systems in which one or more spectrum holes exist between multiple Primary User (PU) frequency bands. The Cognitive Radio Users (CRUs) are able to share any portion of the frequency band with other CRUs and the PUs as long as this does not interfere unduly with the PUs' transmissions. Both Cochannel Interference (CI) from other CRUs as well as Mutual Interference (MI) between the CRUs and the PUs are considered.