NOMA-Enabled CoMP Clustering and Power Control for Green Internet of Things Networks

In this paper, we investigate the clustering and power control problem for coordinated multipoint (CoMP) transmission in green non-orthogonal multiple access (NOMA) networks. NOMA is a promising multiple access technique to support massive connectivity in the case of a large number of Internet-of-things (IoT) devices. Recently, CoMP transmission is introduced into NOMA networks to improve network capacity, which enables multiple access points (APs) to simultaneously serve one device while not cutting off the association with other devices. However, non-orthogonal resource sharing brings interference in AP clusters, which further boosts up the transmit-power consumption. To tackle this issue, we propose a scheme to minimize the total transmit power of APs by jointly optimizing AP clustering and power control. Specifically, the AP clustering is modeled as a many-to-one matching problem with externalities. We design an exchange-matching based algorithm to iteratively update the AP clustering and finally achieve the matching with one-sided stability. Furthermore, we show that the power control with a given AP clustering can be solved by linear programming. Simulation results demonstrate that the proposed scheme can release the potential of CoMP in NOMA networks and effectively mitigate interference to save transmit power while ensuring rate requirements for all devices.