Cooperative device-to-device communications in cellular networks

To meet the increasing demand of wireless broadband applications in 4G/beyond 4G cellular networks, D2D communication can serve as a candidate paradigm to improve spectrum efficiency. By reusing the spectrum of cellular users, two D2D users can form a direct data link without routing base stations and core networks; thus, the spectral efficiency can be improved. Further, when the cooperation between cellular users and D2D users is enabled, a win-win situation can be achieved to make all users better off. Thus motivated, we propose a cooperative D2D communication framework in this article, which introduces the cooperative relay technique to conventional underlay/overlay D2D communications. Adaptive mode selection and spectrum allocation schemes are also presented to ensure better performance for both cellular and D2D users. Extensive numerical results show the effectiveness of the proposed framework for a variety of scenarios.