Graph-based joint mode selection and resource allocation scheme for D2D and cellular hybrid network using SCMA

Abstract

Enabling device-to-device (D2D) communication in cellular network is shown to be a promising candidate in the future fifth generation (5G) wireless network. Specifically, the hybrid architecture leads to flexible and efficient resource allocation for cellular users and D2D users, thereby enhancing utilization of spectrum resources. However, if not properly handled, mutual interference will be significantly raised with the proliferation of devices, which bottlenecks the performance of the hybrid system. In this paper, joint mode selection and resource allocation is considered for a sparse code multiple access (SCMA) enabled uplink cellular network. Targeting at maximizing system sum rate, we formulate a joint optimization problem, which, however, is shown to be a mixed-integer nonlinear programming (MINLP) problem. To solve the problem, we propose a graph-based joint mode selection and resource allocation (GMR) algorithm. GMR is an interference-aware algorithm. In particular, when GMR is applied, D2D users reuse SCMA resources only when the interference level to cellular users is below a predefined threshold. Otherwise, dedicated resources are allocated to D2D users to avoid the overwhelming mutual interference. Simulation results have confirmed the efficacy of GMR in enhancing spectrum efficiency and system sum rate in the hybrid system.