A QoS-Aware Power Optimization Scheme in OFDMA Systems with Integrated Device-to-Device (D2D) Communications

This paper proposes a power optimization scheme with joint resource allocation (i.e. subcarrier and bit allocation) and mode selection in an OFDMA system with integrated D2D communications. Through the proper control of the base station (BS), users can communicate with each other either directly or via the BSs as in traditional cellular networks. Particularly, an optimization problem is formulated to minimize total downlink transmission power constrained by users´ QoS demands; while a heuristic scheme exploiting joint subcarrier allocation, adaptive modulation and mode selection is contrived to solve the problem. Simulation results show that our proposed scheme may not only conserve total downlink transmission power effectively, but also save overall power consumption of BSs significantly, compared with existing algorithms used in traditional OFDMA systems.