The four key components of Cloud RAN
5G calls for new levels of flexibility in architecting, scaling and deploying telecom networks. Cloud technology provides interesting possibilities to complement the existing tried and trusted technologies in the RAN domain. Cloud RAN refers to realizing RAN functions over a generic compute platform instead of a purpose-built hardware platform.
5G calls for new levels of flexibility in architecting, scaling and deploying telecom networks. Cloud technology offers new innovative alternatives for such Radio Access Network (RAN) deployments complementing existing proven purpose-built solutions. Open RAN is an industry term for open radio access network architecture with open interoperable interfaces and hardware-software disaggregation, which enable big data and AI-driven innovations in the RAN domain. To realize this in scale requires leveraging cloud technologies and web-scale paradigms which leads us to Cloud RAN.
Cloud RAN refers to realizing RAN functions over a generic compute platform instead of a purpose-built hardware platform and managing the RAN application virtualization using cloud-native principles. Cloudification of RAN begins with running selected 5G RAN network functions in containers through Commercial off-the-shelf (COTS) hardware platforms. It starts with control plane and user plane in the Centralized Unit and continues with latency sensitive radio processing functions in the Distributed Unit. In this journey, Cloud RAN will adopt leading practices and become a foundation for openness and enable innovation in 5G.
In this blog post we will explore:
- The four components of Cloud RAN
- Key considerations in Cloud RAN
- The value Ericsson brings into Cloud RAN
The four components of Cloud RAN
Ericsson has broken down Cloud RAN into four components that create the foundation for a successful Cloud RAN implementation.
- COTS hardware including accelerators – selecting the right hardware platform and environment.
- Cloud native architecture –realizing RAN functions as microservices in containers over bare metal servers using cloud native technologies such as Kubernetes and applying DevOps principles.
- Management, orchestration and automation - bringing end-to-end life cycle management of services across Cloud RAN, transport, 5G core and underlying cloud infrastructure.
- RAN programmability – deploying non-RAN functions in the virtualized system to add new functionality and additional value.
COTS hardware including accelerators
Selecting the right hardware platform and the virtualization environment is an important first step. Commercial-off-the-shelf server hardware with processors, Network Interface Cards (NICs) and hardware accelerators is the foundation. Specific server configurations are based on workload demands, especially for Distributed Units (DU) with its higher processing demands and stricter requirements on latency. This requires the use of accelerators to manage Layer 1 pipeline functions and is especially critical to meet the demands of Massive MIMO radios.
In coming blogposts, we will discuss in more detail different types of processing architectures including how to best realize an efficient hardware architecture for Cloud RAN.
Cloud native architecture
Disaggregating RAN software and hardware in Cloud RAN has the potential of independent innovation on software and hardware. However, simply forklifting existing 5G RAN software to a COTS platform is not enough. To really realize the value of Cloud RAN one needs to embrace cloud native architecture.
Cloud native architecture facilitates RAN functions to be realized as microservices in containers over bare metal servers, supported by technologies such as Kubernetes. Such software modularity and decomposition allow for:
- Independent life cycle management following DevOps principles and Continuous Integration and Continuous Delivery (CI/CD)
- Scaling of component RAN microservices
- Application-level reliability with platform abstraction
- Simplified operations and maintenance with network automation
Management, orchestration and automation
As the industry is transforming and introducing 5G networks, the management, orchestration and automation has become a cornerstone of 5G networks. With the introduction of Cloud RAN, edge compute, container-based architectures, and network slicing, the management and orchestration systems have become critical for success. These systems will now have to manage physical network functions (PNF), virtual network functions (VNF), cloud native network functions (CNF) and end-to-end life cycle management of services across Cloud RAN, transport, 5G Core and underlying cloud infrastructure.
Under this context, Cloud RAN management is not just about managing hybrid network functions in RAN, but also about bringing cloud native principles, programable networks and model driven management and orchestration systems. This brings key values needed in 5G networks such as automation, flexibility, faster time to market, managing complex networks, and better customer experience.
In an upcoming blogpost, we will elaborate more about how we enable automation, management and orchestration to deliver 5G services across all industries.
RAN programmability is essentially the capacity to tailor the behavior and performance of the RAN through applications with access to multi-domain information. This will also open up the RAN environment to a broader ecosystem and allows developers to build applications completely independently from innovations in the RAN domain. This unlocks new innovation value, enhancing the CSPs role and creates opportunities for monetization.
Programmability of RAN can be done both within the framework of 3GPP and within the complementary specifications of O-RAN. The O-RAN architecture includes two flavors of RAN Intelligent Controller to aid programmability of RAN:
- Non-Real Time RAN Intelligent Controller (Non-RT RIC) – operating in the control loop of 1 second and above.
- Near Real Time RAN Intelligent Controller (Near-RT RIC) – operating in the control loop of 100s of milliseconds
Ericsson sees that the Non-RT RIC is offering the greatest benefit. With its placement higher up in the architecture, it can access a larger pool of RAN data as well as external data sources such as weather, traffic, first responder events etc. to provide policy guidance to RAN on radio resource allocation and the 1 second control loop is short enough to capture almost all possible use-cases.
Given the benefits of being able to bring multidomain knowledge at higher layers, Ericsson is currently focusing its R&D efforts on the Non-RT RIC, as opposed to the Near-RT RIC which overlaps considerably with RAN functionality already provided in feature rich RAN offerings as offered by Ericsson.
Key considerations in Cloud RAN
Cloud RAN journey
Evolution to Cloud RAN is a multi-year journey. A key learning from the virtualization journey of the core is that pre-verified solutions work best and are the most efficient, and that customer unique cloud environments come with additional work, cost and TTM overloads. The Ericsson approach to Cloud RAN is built to be cloud agnostic but to extract maximum value, CSPs should consider a balanced approach to disaggregation. From a technology maturity perspective, Cloud RAN will benefit greatly from clear industry practices and O-RAN innovation with a high degree of alignment towards 3GPP architecture. Ericsson actively contributes to several of these alliances in order to enable innovation at global scale for the benefit of the whole industry. From our experience and domain expertise, we see a five-step journey towards Cloud RAN.
- Evaluate the key use cases and deployment scenarios to decide the right cloud infrastructure. This typically includes the infrastructure hardware, cloud platform and RAN applications that will be hosted on it and the interworking and compatibility with current installed base.
- Virtualization of Central Unit (CU) and especially CU-UP. This is the lower risk starting point and opens up for flexible distributed edge placement of vCU-UP and virtual User Plane Function (vUPF).
- Fully cloud-native realization of both CU-CP and CU-UP. This provides independent scaling for centralized control and user planes and creates locational flexibility in deployments
- Cloud-native realization of the DU function. This brings challenges around server and accelerator selection, cloud infrastructure and OAM, capacity dimensioning, power efficiency planning and security planning.
- Introduce Cloud Native SMO (Service Management and Orchestration) in parallel – Bring RAN programmability to the network and start to capitalize on this foundation for innovation.
Building a disaggregated system
Building a disaggregated system, that actually works as a cohesive entity is complex. The disaggregation of hardware and software means that the RAN solution no longer has a unified node concept, instead consisting of software functions, NFVI and hardware versions, all with their own life cycles and release cadence. Additionally, Radio Access Networks have rather specific processing needs and requirements compared to typical IT applications or even core network workloads.
To build and integrate such a system requires telecom expertise, the ability and experience to deliver pre-verified solutions and solid network evolution capabilities and skills. Cloud RAN will be introduced into live networks with multiple radio access technologies, running predominantly as physical functions, with no impact on the quality of experience for its users. This demands strong knowledge not only of Cloud RAN but of the entire existing telecom stack.
To do this with an IT-focused approach at scale is unproven and current business models do not cater for back-to-back support agreement with RAN component suppliers, indicating an area where Ericsson can contribute to the maturity of the industry over time.
Why partner with Ericsson in your Cloud RAN journey?
Ericsson is a partner for your entire Cloud RAN journey, from design, solution creation, implementation and operations.
- Global RAN expertise: Ericsson brings significant RAN expertise and experience from delivering leading and robust networks throughout the globe.
- Cloud RAN industry practices: Ericsson is a leading contributor to the most important open forums, actively supporting efforts to establish industry practices in Cloud RAN.
- Cloud RAN processing: We bring deep understanding of the demanding processing requirements in 5G RAN and active adoption of cloud technologies for application in the RAN domain.
- Cloud RAN compatibility: Ericsson brings a leading radio portfolio meeting the unique needs of widely different networks and bring features that ensure Cloud RAN interworks seamlessly with installed base. One great example is the unique Ericsson Spectrum Sharing solution.
- Ericsson pre-verified solutions: Ericsson can deliver a pre-verified Cloud RAN solution ranging from cloud infrastructure, RAN software, COTS hardware and accelerators and Radio gateways for optimized transport performance.
- Cloud-native transformation experience: We have successfully helped our customers through a similar multiyear cloud-native core transformation journey.
We have a leading 5G position and rich knowledge of building and running several generations of robust and reliable radio access networks globally. We are delighted to share our expertise and help our customers unveil a whole new world of possibilities with Cloud RAN.