From running limited trials to commercial rollouts and laying the future roadmap for the technology, Open RAN is a significant talking point for the telecoms industry. Twimbit even expressed a detailed report on Open RAN covering the “8 highlights of the Global Open RAN market by 2030”. In addition, it reflects upon the opportunities for Open RAN over the next 10-years, including forecasts for various segments, 4G, 5G, and geographic regions.

Here, we aim to help you understand the basics of Open RAN, its key features, growth drivers, and the ecosystem.

Open RAN is:

• A network architecture focused on disaggregating radio access network components, specifically the baseband, into the distributed unit (DU) and centralised unit (CU).
• A process that decouples software from the underlying hardware, better known as virtualisation, is key to enabling a split architecture.
• This disaggregation with an open fronthaul interface facilitates equipment interoperability from a diverse vendor ecosystem.
• DU and CU components, which may be deployable in cloud environments.

Evolution of Open RAN

vRAN – Decoupling software from hardware and virtualising a part of or the complete baseband unit (BBU) for cloud deployment while the interfaces remain in the proprietary domain.

Open RAN – Opens the transport interfaces between the different baseband processing functions and remote radio units (RRUs), which theoretically allows network operators and equipment vendors to mix and match between units.

Open vRAN – Combines both vRAN and Open RAN for open and virtualised baseband processing functions to maximise deployment flexibility and reduce market time.

Open RAN architecture by O-RAN alliance

Components of Open RAN

O-RU

O-RU is a logical node hosting the Low-PHY layer and RF processing on a lower layer functional split, with a front haul interface sending processed radio frequencies to the O-DU.

O-CU

O-CU is a logical node that hosts a large number of protocols: radio resource control (RRC), service data adaptation protocol (SDAP), and packet data convergence protocol (PDCP).

O-DU

O-DU is a logical node hosting another set of protocols: radio link control (RLC) protocol, medium access control (MAC) protocol, and the physical interface (PHY).

O-Cloud

O-Cloud is a cloud computing platform encompassing a collection of physical infrastructure nodes that fulfill O-RAN specifications, host O-RAN functionalities and support software, management, and orchestration activities.

Radio Intelligence Controller (RIC):

Both non-real-time and near-real-time RICs are different kinds of RICs, in which both are logical functions that control and optimise ORAN elements.

Near-RT RIC is a logical function, enabling fine-grained data gathering and actions over an E2 interface for near-real-time control and optimisation of RAN elements and resources. The E2 interface connects near-real-time RIC with the O-CU and O-DU.

• xApp is an application designed to run on the Near-RT RIC (where the ‘x’ stands for any application). It acts as an independent software plug-in to the Near-RT RIC platform to provide functional extensibility to the RAN by third parties.

The Non-RT RIC allows for non-real-time control and optimisation of RAN elements and resources, AI/ML workflow, model training and updates, and policy-based application/feature guidance in the Near-RT RIC.

• The Non-RT RIC allows applications to be carried out on it, called rApps, where ‘r’ stands for RAN.

SMO

SMO is a Service Management and Orchestration system responsible for RAN domain management. Within the O-RAN, it enables managed functions to communicate and interoperate. Additionally, the SMO is in charge of connecting to and managing the RICs, O-Cloud, O-CU, and O-DU.

Benefits of Open RAN

1. Vendor flexibility:
   1. Telcos can avoid vendor lock-in by replacing vendor-proprietary interfaces with a completely disaggregated RAN based on open standards.
   2. Open RAN allows carriers to collaborate with both established vendors and new entrants, thus increasing industry competition to provide the best solutions for the operators.
   3. Open RAN helps operators quickly scale in network deployment and expand existing network infrastructure.

2. Total Cost of Ownership (TCO):
   1. Allows general-purpose hardware and commercially of the shelf servers (COTS), making Open RAN cost-efficient compared to the traditional vendor proprietary hardware.
   2. Network automation is key to bringing down the TCO through reducing energy use, resource distribution and increasing operational efficiency.

3. Innovation:
   1. Enables robust application and product innovation
   2. Faster market time- As the network infrastructure is software-based, new features can be added more quickly for end-users.

Current status of Open RAN

Open RAN deployments

Open RAN growth drivers

1. Disaggregated and virtualised networks
   1. Split or distributed architecture is a prerequisite for 5G networks
   2. Open RAN will benefit from the fast virtualisation of RAN
2. TCO optimisation & vendor flexibility
   1. Use of general-purpose hardware and commoditisation of radio
   2. Vendor diversity to break market monopolies
3. Rural deployment
   1. Bridging the digital divide by extending network coverage in rural areas is much easier for operators with the lower deployment cost of Open RAN
4. Government incentivisation
   1. US: Injected US$ 750 million in funding over 10 years to accelerate the development of Open RAN solutions 
   2. UK: Multiple grants released through OFCOM for Open RAN lab, R&D, trials, and deployment incentives
   3. India: The Indian government has encouraged local vendors to develop local telecom equipment supply chains under its “Make in India” incentives 

Open RAN vendor ecosystem

Challenges of Open RAN

With a broad range of solutions from multiple vendors, integration and interoperability between the different equipment used in the Radio Access Network become the primary challenge, followed by:

1. Performance and feature consistency
2. Legacy and backward compatibility
3. Secure, consistent network performance
4. Maintenance and effective operation of the network

Twimbit analysis

1. Early adopters and deployment trials drive the founding growth of the Open RAN market.
2. Low market share remains in the early stages as mobile industries are sceptical of multiple complications arising from the multi-vendor structure.
3. Market penetration is expected to grow up to 3X from 2023 – 2027, as momentum continues forward to the end of the decade, where Open RAN dominates more than half of the total RAN market.

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Head to our quiz via the link: Open RAN fundamentals quiz