查看文章

We investigate the ergodic uplink resource allocation problem for secure communication in relay-assisted orthogonal frequency-division multiple access (OFDMA)-based cognitive radio networks (CRNs) in the presence of a set of passive eavesdroppers where relay nodes assist the legitimate users to transmit their messages. Previous works have commonly assumed the availability of channel state information (CSI) for this type of problems. However, due to the decentralized nature of CRNs and hidden activities of eavesdroppers, the assumption of availability of exact values of CSI is not realistic. In this paper, we consider uncertainty on the estimated values of CSI between different transmitters and receivers, e.g., CSI between each legitimate transmitter and its corresponding receiver and CSI of each legitimate user and each eavesdropper. We utilize the worst-case robust formulation to find power and sub-carrier …