Deutsche Telekom, Orange, Telefonica, TIM and Vodafone detail Open RAN interests—SMO, RIC, RAN hardware acceleration are focus areas
As Open RAN has becomes mainstream, the industry focus has shifted from supplying greenfield network builds to integrating new, open radio systems into brownfield networks. For Open RAN to be a success here, it’s important for standards bodies and vendors to align with the real world needs of operators. Fortunately, a group of major European operators have spelled out their technical priorities.
Deutsche Telekom, Orange, Telefonica, TIM and Vodafone are parties to a memorandum of understanding, initially executed in 2021 with TIM coming on board later, that details the companies’ commitments to deploying Open RAN. While deployment has already begun in many of the markets this group of operators serve, it’s a long-term commitment and, as such, the group have annually updated their technical priorities.
The fourth publication of technical priorities came from the quintet in June. Reiterating for the industry at large the goal of publishing these technical priorities, the group described the focuses as meant to “serve as guidance to the RAN supplier industry on where they can focus to accelerate market deployments in Europe, focusing on commercial product availability in the short term, and solution development in the medium term…which can then be developed with the industry at large to create requirements that can potentially be used as the basis for certification, promotion an efficient supply chain.”
With the fourth release, the European operators gave air to their thinking around service management and orchestration (SMO), including the non real-time RAN Intelligent Controller (RIC). Specific comments were on:
- An artificial intelligence (AI) and machine learning (ML) framework “for model training interaction and integration of the SMO, as well as the specific monitoring of a model’s behavior.”
- Integration with legacy radio equipment acknowledging that “the transition phase and virtualization steps are ongoing but cycles for legacy hardware replacement are long.” The group points out that because SMO, non real-time RIC and rApp capabilities “already exist for non-Open RAN systems” and are “more advanced in terms of full [Operations Support System (OSS)],” traditional and Open RAN systems should use the same interfaces.
- Network slicing requirements “were added related to interaction of rApps and the [RAN Network Slice Subnet Management Function (R-NSSMF)] and the mastership and synchronization of respective RAN parameter, which also relates to the Conflict Management.”
With regard to the ongoing industry debate around inline or look-aside RAN hardware acceleration, the European operators didn’t take sides, but rather observed, “Support for both options is not widely endorsed in the industry by RAN [software] and infrastructure vendors, who are choosing between these two to develop and implement their own stack. Standardization bodies are working on defining a framework…that will facilitate integration of both alternatives and even possibly support seamless transition from one option to the other one: however, this is still in early stages.” The summarized requirements are:
- Hardware/software “decoupling and abstraction at different levels…and among different [software] levels” following the O-RAN Alliance’s work on the Acceleration Abstraction Layer (AAL).
- Support for multiple radio access technology (multi-RAT) systems “with flexible distribution of compute between RATs.”
- “Multi-vendor support facilitating [software] portability and integration across different [hardware] using open interfaces.”
- Power consumption optimization based on traffic load.
- Network connectivity consideration, including input/output ports and speed, timing and synchronization capabilities and peripheral component interconnect (PCI) across form factors.
- And “independent lifecycles between hardware and software.”
“Operators require technology and vendor agnostic solutions,” they wrote. “Their choice for a specific solution for RAN [hardware] acceleration relies only on best-of-breed technology regarding performance, energy efficiency, hardware footprint, and technology evolution.” The “short-term assessment is [that the] ecosystem should evolve fulfilling these requirements to facilitate and embrace the principles of Open RAN, such as openness and multi-vendor approach. In parallel, but medium to longer term, [we] will suggest for introduction of more capabilities such as AI/ML functions, advanced automation and [silicon] integration to enhance and optimize [the] physical layer.”
Also included in the latest technical priorities were enhanced requirements for the O2 interface that connects the SMO to the open cloud platform, and the addition of new radio bands and power requirements to the open radio unit (oRU), among other items.
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