Inter O-DUs Coordination for Scheduling of Massive Users in O-RAN

Open Radio Access Network (O-RAN) is a decentralized, intelligent, and open network architecture. RAN Network Functions (RNF) are split into Open Central Unit (OCU), Open Distributed Unit (O-DU), and Open Radio Unit (ORU), which are deployed on commercial hardware and cloud nodes as containerized Network Functions (CNFs). This paper presents a coordination architecture between O-RAN Distributed Units (O-DU) for scheduling massive number of users. We propose a Non-Orthogonal Multiple Access (NOMA) based access technique for interference avoidance and scheduling of such massive number of users through a cooperative strategy. This involves sharing individual scheduling tables to compute interference for subsequent User Equipment (UEs) transmissions in the network. The results of the interference calculations are then fed into ODU schedulers. The scheduler of each O-DU shares the radio resources among the UEs to have minimum interference. The proposed scheme's effectiveness in terms of throughput, energy efficiency, and connectivity is examined through simulations. The results show that the proposed method reduces the effects of interference, making it better suited to the needs of dense deployments. Users operating under the proposed approach experience up to +30% and -10% improvements in achieved user data rates and energy consumption, respectively, when compared to the absence of a coordination architecture.