About O-RAN O-DU Testing
Open RAN (ORAN) architecture disaggregates and splits traditional RAN into CU (Centralized Unit), DU (Distributed Unit) and RU (Radio Unit), supporting standardized open and interoperable interfaces, and allowing key functions to run as virtualized software functions on vendor-neutral hardware. This avoids single-vendor dependency by opening the architecture to multiple suppliers.
The DU sits between the CU and one or more RUs. The DU is a logical node hosting RLC/MAC/High-PHY layers based on a lower layer functional split. A single DU can manage many RUs. DUs can be virtualized and deployed on vendor-neutral COTS hardware. Disaggregated architecture, open interfaces, virtualization, multi-vendor interworking, and cloud deployments are some of the many challenges that mandate comprehensive testing of the DU.
The DU can be tested in isolation, in wraparound testing mode. In this case, Landslide emulates all the network functions surrounding the DU, including RUs & UEs, Core network, eNBs/gNBs, neighboring CUs and RIC. The Core network emulation can be 5GC for SA mode or it could be the EPC for NSA mode.
Key Features
The Landslide DU Testing feature set includes the following capabilities:
• Single UI controls all functional blocks
• Standalone (SA) modes
• Emulation of UEs, CUs, RUs and 5GC and/or 4G EPC to surround the DU being tested
• Relevant interfaces 7.2x. F1-C, F1-U, E2, O1 are supported
• Control plane and user plane testing
• Functional, performance & capacity testing
• Support for intra-DU & inter-DU mobility scenarios
• High performance solution that can be scaled to multiple RUs, each RU with up to 256 emulated UEs
• Call modeling capabilities to shape test traffic as needed, for control and user planes
• Highly customizable, with ability to edit messages onsite as needed
• Automation through RESTful or Tcl API
Benefits
Landslide DU testing provides a flexible, scalable, high- performance solution for comprehensively testing the DU for compliance, functionality, performance & capacity. With the need to interoperate with network functions from different vendors, compliance to the specification is of paramount importance. The continuously evolving specifications are sometimes subject to interpretation. As such, components like Information Elements (IE) might be included or excluded from certain procedures, depending on the vendor. Message editing capabilities provided by Landslide empower users to make on-the-fly modifications to adjust for these situations. Powerful traffic modeling capabilities allow users to shape the traffic as needed, both for the control and user planes. This enables easy replication of live network traffic conditions, patterns, and scenarios in the lab.
Some of the key use cases that can be addressed include:
• DU, EPC, 5GC, eNBs and gNB interoperability
• CU DU capacity
• DU Performance
• Mobility
• Single UE and aggregate data throughput
• Real-world user plane traffic performance (such as HTTPS, FTP, and application traffic such as Facebook, YouTube, Zoom, etc.)
• Voice and video quality
• Ability to manage real world traffic mix and different types of mobility events
• DU robustness for handling abnormal, non-compliant messages & scenarios for negative testing and security
• CI/CD automation pipeline integration
Test Cases
An intuitive, easy-to-use graphical interface enables quick configuration & execution of tests and analysis of test results. Landslide also provides robust automation options including RESTful & Tcl APIs. - Using the RESTFul API , Using the TCL API
RIC (RAN Intelligent Controller) Node test case -RIC Node Emulator Configuration , RIC Node Parameters
RIC (RAN Intelligent Controller) Nodal test case - RIC Nodal Test Configuration, RIC Nodal Parameters
DU Nodal test case : - DU Nodal Testing
External Data support for UE Emulator - UE Emulator Data Node Emulator Configuration , DU Nodal Testing
Alternative O-RU Emulation via Spirent Vertex Baseband Synchronizer.
Technical Specifications
Landslide DU Testing is compliant to specifications:
ORAN Alliance Interfaces 7.2x. F1-C, F1-U, E2, O1 (E2 and O1 are H1/23)
Definitions:
- ORAN – Open RAN
- O-CU - (Centralized Unit) - O-RAN Central Unit – a logical node hosting PDCP, RRC, SDAP and other control functions. This can be considered short-hand for the O-CU-CP and O-CU-UP in an O-RAN system.
- O-DU – (Distributed Unit) - O-RAN Distributed Unit: a logical node hosting RLC/MAC/High-PHY layers based on a lower layer functional split. O-DU in addition hosts an M-Plane instance.
- O-RU – (Radio Unit) - O-RAN Radio Unit: a logical node hosting Low-PHY layer and RF processing based on a lower layer functional split. This is similar to 3GPP’s “TRP” or “RRH” but more specific in including the Low-PHY layer (FFT/iFFT, PRACH extraction). O-RU in addition hosts M-Plane instance.
- C-Plane - Control Plane: refers specifically to real-time control between O-DU and O-RU, and should not be confused with the UE’s control plane.
- S-Plane - Synchronization Plane: Data flow for synchronization and timing information between nodes
- U-Plane - User Plane: refers to IQ sample data transferred between O-DU and O-RU
- NSA - Non-Stand-Alone network mode that supports operation of SgNB attached to MeNB
- SA - Stand-Alone network mode that supports operation of gNB attached to a 5G Core Network
5G Glossary Acronyms, Terms and Specifications in 5G-Glossary