Subcarrier sharing scheme for overlay anc cooperative D2D communication in cellular networks

Device-to-device (D2D) is a new communication paradigm which has evolved recently to meet the capacity requirements of 4G/beyond 4G cellular networks. In a generic D2D framework, two cellular users living in close proximity can form a direct link for data transmission without routing it through the base station (BS). However control or signaling information between the users will still be carried out by the BS. In this paper, we augment the development of D2D communication by proposing an orthogonal frequency division multiplexing (OFDM) based subcarrier sharing scheme to facilitate D2D communication between cellular users. Analytical expressions for outage probability for two different D2D frameworks namely overlay and cooperative D2D have been derived. Through the obtained results, we can determine the exact number of subcarriers available for D2D communication while fulfilling the target rate and outage probability constraint of cellular system. It also has been shown that for low cellular outage constraint, overlay performs better than cooperative D2D whereas for high cellular outage constraint, the cooperative D2D framework completely outperforms the overlay D2D framework.