A New Relay-Assisted Spectrum Sharing Scheme for Bidirectional Communication

In this paper, we propose a new relay-assisted spectrum sharing protocol where a pair of secondary users and a pair of primary users bidirectionally communicate. A secondary relay is deployed to assist the secondary transmissions and improve the secondary access to the spectrum. We employ a time division access technique to make primary and secondary users communicate with no interference. The proposed scheme is then compared to the axiomatic and simple scheme where the secondary users communicate in an underlay mode with the assistance of the relay . We study and compare the performances of the two schemes in terms of outage probability. Our simulation results show that the proposed scheme significantly outperforms the underlay spectrum sharing scheme while in both schemes, the primary outage probability is kept identical to the case where secondary users are absent.