Compressive cognitive radio with causal primary message

摘要

Compressive sensing (CS) is an emerging theory in that it is possible to reconstruct sparse signals from far fewer measurements than traditional methods use. Existing studies utilizing CS in the field of cognitive radio network (CRN) mainly focus on spectrum sensing in interweave mode. However, few works concern about the application of CS in overlay CRNs. In this paper, we study the overlay CRN, which applies CS technology as a joint source-channel code. The secondary user (SU) not only sends its own message, but also employs decode-and-forward relaying strategy to help with primary transmission, where the primary message is obtained in a causal manner. Dirty paper coding is used to pre-cancel the interference of the primary message at the secondary receiver. We discuss the coding schemes when one SU and two SUs are in the CRN. To either case, we formulate the corresponding system optimization problem, which maximizes the secondary rate while satisfying the primary rate requirement. The performance of the proposed scheme is evaluated by numerical simulations and compared with the nonoptimal causal scheme and the non-causal scheme.