Two decode-and-forward relaying schemes for cooperative cognitive radio systems

In this paper, two cognitive cooperative decode-and-forward (DF) relaying schemes are proposed based on corresponding cooperative cognitive radio models. The two models named Model A, and Model B are the extensions of the conventional cooperative relaying model, where Model A and B are based on the division of the time duration and spectrum bandwidth. The cognitive cooperation schemes, which are composed of the necessary cooperation conditions and the resource allocation algorithms, are given for each model, respectively. These schemes aim to maximize secondary uesr's (SU) own transmission data rate while keeping the data rate of the primary user (PU). Numerical results show that under the same constraints, the scheme for model A can bring higher data rate of SU; the scheme for model B brings more energy saving of the PU; in the two schemes, the data rates of SU's own transmission both reach the top when the secondary transmitter (ST) of the SU is located in the middle between the primary transmitter (PT) and the primary receiver (PR).