RF over CPRI (RFoCPRI)

Benefits of RFoCPRI

Modern cell sites have a distributed architecture where the base-station transceiver subsystem (BTS) is divided into two main elements:

• The Baseband Unit (BBU) is the digital processing system interfacing to the core of the network via the backhaul and to the remote radio unit (RRU) via the fronthaul, responsible mainly for Layer 1-3 communication functions.
• The Remote Radio Unit (RRU) is the radio system that interfaces with the BBU via the frounthaul and with the antenna system, performing digital-to-analog and analog-to-digital conversions, RF up/down conversions, amplification, and filtering to transmit and receive signals over-the-air on the assigned upllink and downlink carrier frequencies.

The BBU and RRU communicate via the common public radio interface (CPRI). As RF access is only available at the top of the tower, the ability to detect interference can be a challenging, dangerous, and expensive task.

RF over CPRI, or RFoCPRI, technology enables effective interference analysis from the base of the tower, minimizing tower climbs, reducing safety concerns, and lowering maintenance costs.

VIAVI introduced the RFoCPRI test function to enable radio access technicians to analyze uplink spectrum in real time and identify interference products, including passive intermodulaion (PIM). Using a non-intrueively approach, directly on the CPRI fronthaul, this solution support flexible CPRI mapping techniques implemented by different radio manufacturers, providing accurate visibility across multi-vendor and multi-version radio deployments.

VIAVI offers RFoCPRI testing on its field test solutions OneAdvisor 800 and T-BERD/MTS 5800 network tester