Resource Management for an Integrated OFDMA Cellular System with MC-CDMA Based D2D Communications

Integration of device-to-device communications (D2D) into cellular networks improves the efficiency and flexibility of the overall system. Besides, D2D can provide partial solutions for some of the inherent problems of cellular systems, such as performance enhancement at cell edges. Similar to cellular systems, interference management is one of the key issues since it greatly affects the system performance. In this paper, we propose a novel and practical resource scheduling scheme for the integrated system. In such a system, multicarrier code division multiple access (MC-CDMA) is used as the multiple access scheme for D2D user equipment (UEs), while orthogonal frequency division multiple access (OFDMA) is used for cellular UEs. The basic idea is to eliminate interference between UEs using different domains (mainly frequency, code and power domains). Furthermore, the combination of resource management, power control, and frequency domain spreading (wideband transmission) leads to an efficient way to realize incell resource reuse between different modes of UEs. Network simulations show that critical interference between different modes of UEs can be well eliminated, while the general SINR performance is acceptable. Spectrum efficiency is improved as well. The proposed scheme provides a simple and practical solution for the integrated system. From both the SINR performance and latency points of view, the solution is robust and promising