QoE-Centric Multimedia Relay in Energy Efficient NOMA Wireless Communications

In Non-Orthogonal Multiple Access (NOMA) downlink the Base Station (BS) transmits to multiple User Equipments (UEs) at the same time and the same frequency with different power levels. However making full use of the promising NOMA technology to relay multimedia contents for UEs in wireless media service is an open issue. In this paper, a Quality of Experience (QoE)-centric multimedia relaying scheme is proposed, where the NOMA is not only applied at the downlinks between the BS and UEs, but also at the Device-to-Device (D2D) relay links among UEs during the relaying phase. By mathematically analyzing the Signal to Interference plus Noise Ratio (SINR) model in downlinks and D2D relay links, we show that the new QoE-centric relay scheme would significantly improve the multimedia QoE of UEs, especially for the UEs with low SINR. In addition, the QoE and energy consumption models are developed in order to comprehensively analyze the system performance. Finally, through numerical simulation we quantitatively analyze the energy efficiency and QoE performance of UEs in different NOMA systems with various numbers of UEs.