near-RT RIC

The near-RT RIC is where O-RAN puts the fast, data-driven control logic that used to be buried inside a vendor's base station. It hosts xApps — modular bits of optimisation software — and connects to the O-CU and O-DU over the E2 interface. The "near-real-time" window is the defining constraint: it acts on a loop somewhere between about 10 ms and a second, fast enough to influence scheduling, handover, and load decisions but not fast enough to be in the per-slot critical path (that stays in the O-DU).

Think of the division of labour this way: anything sub-10 ms is too quick for the RIC and lives in the DU's MAC scheduler; anything slower than a second is handled by the non-RT RIC up in the SMO. The near-RT RIC owns the middle. It subscribes to telemetry from the RAN nodes over E2, runs xApp logic, and sends back control or policy. It also takes guidance from the non-RT RIC over A1 — high-level policies and ML models it then enforces on the faster timescale.