RuSIM - O-DU Testing Solution - Emulating the O-RU over the O-RAN Fronthaul

O-RAN Fronthaul Validation Made Simple

Keysight Technologies is a founding member and active contributor for  O-RAN Alliance Work Group 4, primary editor of the O-RAN Alliance WG4 Fronthaul Conformance and Interoperability Test Specification.

For testing over the O-RAN fronthaul interface, Keysight has successfully deployed with multiple industry players the RuSIM, a 4G and 5G UE and O-RU emulator. RuSIM enables infrastructure vendors, chipset providers and mobile operators and integrators to easily run functional testing, conformance testing and performance testing of O-RAN Distributed Unit over the option 7.2x functional split fronthaul interface.

For testing over the O-RAN fronthaul interface, Keysight has successfully deployed with multiple industry players the RuSIM, a 4G and 5G UE and O-RU emulator. RuSIM enables infrastructure vendors, chipset providers and mobile operators and integrators to easily run functional testing, conformance testing and performance testing of O-RAN Distributed Unit over the option 7.2x functional split fronthaul interface.

RuSIM enables network verification by generating IP traffic load, simulating applications running on multiple concurrent devices operating real voice and data sessions. Full protocol stack assessment is possible for 5G NR (NSA/SA) over eCPRI. O-DU full-stack testing can be performed with an optional wrap-around testing configuration, using CuSIM, the Keysight’s  O-CU emulator. CoreSIM, the Keysight core emulator, makes O-DU+O-CU wrap-around testing possible.

Validate 5G RAN functionalities, conformance and performance over the  O-RAN fronthaul interface

• Virtualized, migrating to Cloud

• Full protocol stack assessment

• Functional testing

• Performance and load testing

• Protocol conformance testing

• Compliance testing against interoperability specifications

• O-DU or O-DU-O-CU wrap-around testing options

O-DU Testing challenges

Despite the standard interface, O-DU testing presents several challenges.

• O-DUs bring-up sequence, due to lose O-RAN standard in this area

• Front-haul timing, given the tight requirements of O-RU, specifically for features like TDD, MIMO and multi-RU Carrier Aggregation

• M-Plane implementation, where the intentional specification flexibility creates significant interoperability issues (i.e. YANG Object Models have 6,000+ parameters, with less than 3% mandatory)

• CU-Plane, with O-DUs designed to work with very specific O-RU capabilities (i.e. only one O-RU category, or beamforming model sets)

• MU-MIMO, requiring close cooperation with O-DU vendor due to vendor specific operational aspects (e.g.: SRS-based + Beam weights) despite standardized communications across O-RAN interface.

Complete Protocol Implementation

Keysight RuSIM implements the functional splits 7.2a and 7.2b over fronthaul interface.

It simulates the CUS and M-Plane interfaces defined by the specifications under O-RAN Alliance.

• M-plane: All YANG models are supported

• S-plane: Full PTP synchronization to a Master residing in the DU (LLS-C1) or elsewhere in the fronthaul network (LLS-C2 through LLS-C4) is supported.

• C-plane and U-plane: Support for multiple downlink and uplink endpoints and alternate numerologies, as well as static and weight-based dynamic beamforming and other advanced O-RU features.