Optimal and Suboptimal Resource Sharing Schemes for Underlaid D2D Communications

Being attracted by offloading local services to adjacent users, the operator allows two proximity users to build up a direct communication link, which is a new supplementary to current cellular network and called device-to-device (D2D) communication. Due to the low power radiation and occupation of the licensed band, D2D users can share the resource with cellular users fully controlled by cellular network to improve the local frequency efficiency. Due to the combinatorial and nonconvex nature of formulated problem, solving such problem optimally is a nearly impossible task. However, we propose an upper bound computation method, which can be seen as a benchmark for resource sharing scheme design. We also propose another two suboptimal schemes, i.e., suboptimal resource sharing scheme I with parallel computation structure which can achieve optimality in the most cases, and suboptimal resource sharing scheme II with relatively low complexity at the cost of acceptable performance loss. Moreover, through extensive numerical results, we find that both suboptimal resource sharing schemes can outperform the existed works. To conclude, our work actually provide a tradeoff between complexity and performance.