The need to improve the agility, scalability and flexibility of networks has been growing. To this end, solutions such as open radio access network (RAN) and cloud have gained traction in recent years.

Open RAN is expected to deliver a plethora of economic and technical benefits over legacy RAN, including solution flexibility, scalability and supply chain efficiency, alongside reducing vendor lock-in and spurring competition and innovation in RAN infrastructure.

Given the potential benefits of open RAN, telecom operators around the world have announced plans to switch from le­gacy RAN to more efficient network architecture. Open RAN has now become a re­a­lity, as both greenfield and brownfield de­p­loy­ments are happening globally. While the technology is still at a nascent stage and is yet to achieve widespread commercialisation, there is growing commitment fr­om numerous stakeholders, including governments, to accelerating its adoption. Ac­c­ording to a report by the Dell’Oro Group, open RAN is projected to approach 15 per cent of total RAN by 2026. Mean­while, a report by ABI Research forecasts that the market for open RAN will surpass the traditional RAN market by 2027 or 2028.

In this scenario, complementary technologies, namely, software-defined networking (SDN) and network function virtualisation (NFV), are significantly simplifying the management and deployment of open RAN.

Virtualising RAN

Mobile network operators (MNOs) are leveraging technologies such as virtualisation for the automation of the software co­m­ponents of open RAN architecture. Vir­tua­lisation involves decoupling the software and hardware elements of networks. The technology uses common hardware with virtualised RAN (vRAN).

vRAN and open RAN are interrelated efforts to abstract radio network operation into software functions. A fully virtualised RAN can bring substantial harmonisation be­nefits and simplify network management, reducing operations and maintena­n­ce costs. Additionally, it offers an opportunity to employ established solutions available in public cloud technologies for non-RAN-specific functions. This eliminates the need for costly vendor-specific solutions. vRAN also offers higher flexibility in terms of deployment of enhanced functionality and capacity. Cloud technologies can facilitate such flexibility. Moreover, with the separation of network functions and processing hardware, RAN functions from multiple vendors can even run on

sh­a­r­ed hardware, further increasing the flexibility for telecom providers. Finally, widespread adoption of open platforms can en­able cross-domain innovation, fostering development of new use cases and services.

As per industry reports, the global vRAN market is expected to grow fr­o­m  $1.1 billion in 2020 to $6.4 billi­on by 2030, driven by the expanding adoption of digitised technology and internet of things (IoT)-connected devices, coupled with increasing data traffic.

Network softwarisation

Network softwarisation can be expressed as a holistic approach to the design, dep­loyment, control, management and orch­es­tration of network components by software. Softwarisation is radically changing the design and operations of communication infrastructure, spurring innovation and dynamic service creation. It is being propelled by the maturity of technologies such as NFV and SDN. Softwari­sa­tion of networks is one of the key en­ab­lers of the future internet evolution, pav­ing the way from 5G to next-generation communication systems such as 6G.

Cloudification and open RAN

Telco cloudification essentially means hosting or using network resources and services from the cloud. They could be private, public or hybrid. There are various levels of cloudification, such as cloud-enabled, whe­re­in some services continue using legacy systems while others are provided through the cloud; cloud-based, wherein the entire network is in the cloud; or cloud-native, whe­rein services are built in the cloud.

Only a few years ago it was believed that cloud computing had no place in telecom networks, which were considered the domain of specialised, purpose-built appliances. However, the emergence of NFV enabled the entry of cloud as a core component of future telecom networks. The first step in an MNO’s journey to the cloud is virtualisation and softwarisation of networks. NFV and SDN are two key pillars of telco cloudification. The third pillar is open source development, as it accelerates cloudification by providing the necessary innovation and development in a timely manner.

Cloudification is a core component of open RAN networks. A modern cloud-native implementation of open RAN wou­ld rely on securing the underlying micro­services-based architecture. To this end, open RAN has open cloud embedded in its architecture, which is a cloud computing platform made up of physical infrastructure nodes employing open RAN architecture. Cloud RAN, then, involves realising RAN functions over a generic compute platform instead of a purpose-specific ha­rd­ware platform. It is a virtualised RAN designed to be cloud-native. It is built with future-proof architecture and incorporates key elements such as microservices and containerisation.

Two recent trends have advanced the cloudification of telecom networks. First, operators have started leveraging cloud business and cloud management practices such as infrastructure-as-a-service for their network functions. Second, cloud-native software, in the form of microservices and Kubernetes containers, has proliferated in the design of virtualised network functions.

The merits of cloud in the network ecosystem are indisputable. A cloud-native open RAN solution enables workflow or­chestration and network automation, whi­ch is required for simplification of network management and to ensure the scalability and agility of operations. It offers long-term benefits for MNOs, including zero-touch provisioning, continuous integration/continuous delivery, artificial intelligence- and machine learning-enabled network monitoring and optimisation. Clou­di­fication is becoming increasingly crucial for telcos to cut IT operating costs.

Industry trends

According to experts, the involvement of a big public cloud can provide enormous impetus to the adoption of open RAN. In addition, several prominent cloud vendors, including Amazon, Google and Microsoft, have partnered with telecom service provi­ders to support the migration to cloud-na­tive open RANs.

As per industry reports, Asia Pacific is expected to dominate the open RAN market with about a 35 per cent share, reaching $11.5 billion by 2030. While Japan is ex­pected to drive the Asia-Pacific market initially, China will emerge as a leader in this region by 2030. Meanwhile, North Ame­rica and Europe will grow by over 45 per cent, but they will account for around 31 per cent and 26 per cent of the market, respectively.

Developments in India

In India, the open RAN environment is developing gradually. The Telecommuni­ca­tion Engineering Centre, a technical arm of the Department of Telecommuni­ca­tions, signed a five-year MoU in May 2022 with an Indian product engineering and manufacturing company that works in 5G, networking and IoT. The MoU will allow registered start-ups, innovators, and mic­ro, small and medium enterprises working in open RAN to test their products at the company’s labs for interoperability bet­we­en open RAN components from various vendors. Components inclu­de the (remo­te) radio unit, the distributed unit and the central unit.

Further, the Centre for Development of Telematics has signed an agreement with VVDN Technologies and the IIT Hy­de­rabad-incubated start-up WiSig Net­works to develop 5G open RAN products and other equipment.

Moreover, Indian telecom players are eyeing open RAN as a viable method to reduce network-related costs as they up­gra­de their networks to 5G technology. All the three major telcos of India have a presence in the O-RAN Alliance and are ex­plo­ring the open RAN domain. Bharti Air­­tel was the first operator in India to co­­m­mercially deploy an open vRAN solution based on disaggregated and open architecture defined by the O-RAN Alliance. In April 2022, it conducted India’s first open RAN-based live 5G network validation in partnership with Mavenir.

Challenges and outlook

Several concerns need to be addressed while planning the deployment and management of networks based on open RAN architecture. These include ensuring interoperability, manageability, optimisation and end-to-end performance in a mul­tivendor environment. Additionally, there exists the possibility of facing incompatible configurations due to the multiple possible combinations of software and hardware. More­over, operators’ expenses on testing in a mul­tivendor environment are likely to rise. Troubleshooting may also become difficult, as operators will re­quire vendor-indepen­de­nt validation and troubleshooting to resolve network performance issues, which might not persist in traditional single-vendor networks. Further, operators will need to integrate multivendor testing processes from the lab to the field to fully realise the benefits of open network architecture.

Movement towards open RAN has progressed significantly in just a few years. Tra­nsition from traditional RAN to open RAN gained significance in 2020, and the mo­men­tum with commercial deployments and the broader movement has continued ever since, supporting the idea that the industry is embracing cloudification of networks and deployment of open RAN solutions.