5G ORAN In-Building Network Design | Mobile Network Operator (MNO) Considerations | Corning

Top 3 Considerations for MNOs Designing a 5G ORAN In-Building Network

By Shirish Nagaraj
Published: July 6, 2022

As discussed in our prior blog on ORAN, while mobile network operators (MNOs) benefited tremendously from the shift to the Centralized RAN (CRAN) architecture from traditional RANs in the past decade, the advent of Open RANs (ORANs) may offer even greater benefits for MNOs. The MNOs are likely to adopt this new 5G ORAN architecture for their greenfield outdoor and indoor network builds going forward due to cost savings, network flexibility, scalability, speed, and ease of deployment reasons.

Given our extensive in-building deployments coupled with our active involvement within the O-RAN alliance, we are becoming a preferred partner for MNOs opting for 5G ORAN indoor networks. As network owners rationalize architecture choices, they often benefit from a checklist that can help them evaluate options and make a sound investment decision. In this article, we will discuss the Top 3 consideration for an MNO when opting for a 5G ORAN in-building network. In a subsequent blog, we will provide a similar guide from a building owner’s perspective knowing that the goals and objectives for a property owner can differ from that of an MNO.

While network owners globally are actively evaluating 5G ORANs, the discussions around open architecture will increasingly begin to focus on the “how” versus the “if.”   


For MNOs looking at cost savings and lower cost of ownership (TCO), the 5G ORAN ecosystem delivers the greatest savings given the reduced capital and operating expenditures required. Increased vendor competition and use of non-proprietary components lowers the capital cost of the components used. The ecosystem being created by ORAN is also something RAN OEMs can take advantage of due to the diversity of ODM partners providing ORAN compliant components. Use of virtualized RANs running on a cloud architecture ensures that operational costs remain low for any network upgrades and enhancements, utilizing the latest advances in cloud workload orchestration, networking, and management.

The great news is that the cost optimization will continue to happen as the server costs and transport network costs will benefit from economies of scale. This will lower the TCO over the ensuing years even further. Currently, with the inflation rates soaring, it is difficult to comprehend a scenario where the costs are lowered. However, over time, higher scale and experience of deploying such networks will bring the overall cost of the 5G ORAN down, driving further benefits for the MNOs.


Being an eco-system approach versus a vendor focused implementation, 5G ORAN promotes interoperability and non-proprietary component use. Besides, the 5G RAN will be highly virtualized with the disaggregation of the hardware and software components in the RAN. In a virtualized RAN, the baseband units (BBUs) primarily reside in either centralized cloud data centers or in a distributed edge cloud closer to the premises. The network functions are disaggregated into a centralized unit (CU) and distributed unit (DU).

The DU primarily takes care of the baseband functions along with user scheduling and medium access control (MAC) and radio link control (RLC) functionality. Given the latency critical and real-time nature of these functions, the DU is expected to be hosted closer to the radio unit (RU), either on-premises or on an edge cloud server. The CU carries Layer 3 radio resource control (RRC) control plane functionality along with packet data processing for the user plane and is not latency sensitive. As a result, much of the CU functions (especially the control plane) can be hosted on a centralized cloud server. RAN functionality can be made to be highly available and fault tolerant by using cloud native approaches to high availability. Since both the CU and DU can be centrally managed (configured and monitored) using cloud orchestration mechanisms, this topology enables a rapid deployment and seamless provisioning of the 5G network when compared with the traditional RAN or CRAN architectures.

With the real time and mission-critical functions typically residing in the DUs closer to the edge of the network, a well-designed 5G ORAN solution can be architected to scale effectively. For in-building networks, security is a key consideration since the radios and DU servers are on premises often without physical security guarantees, unlike in a Macro network. To this end, IPSEC encryption ensures secured mid-haul data connectivity for the control and management plane, while the inherent support of security in the Packet Data Conversion Protocol (PDCP) in the CU-DU split architecture ensures end-to-end data plane security. All in all, the bases are well covered for the MNO when evaluating 5G ORAN as the architecture for the future, especially for in-building networks.


RAN innovation has historically been constrained by the lack of competition. Vendor diversity opens the aperture with new possibilities, approaches and functionalities surfacing for the MNOs. For network owners and operators looking for innovative solutions, both today and in the coming years, the use of best-in-class and high-performing components in their networks will enable feature-rich applications and advanced capabilities in their networks. With increased product enhancements, the MNO’s service offerings will improve and the entire mobile experience for the subscribers will be elevated.

The road to private networks for the MNOs goes through RAN sharing and support of 5G ORANs. The promise of convergence on the outdoor and indoor networks, unification of the macro and urban deployments, and a host of other deployment scenarios will benefit from the innovation in the RAN which will be best delivered in the new open architecture. MNOs looking for innovation in their RAN will need to opt for 5G ORANs for future gains.


As we have taken the huge step towards an open architecture and embracing vendor diversity, the deciding factor will be in the ability to integrate the offerings and ensuring a high-performing 5G ORAN in-building network. System integration is a complex task and unless the whole solution is brought together seamlessly to work as one unified well-designed system, the benefits of openness will be dampened by lack of seamless interoperability. It is critical that the system is managed end-to-end and put together as if it came from a single vendor. The system integrator ecosystem’s ability to integrate the entire solution efficiently will become critical to the success of the 5G ORAN architecture deployment.

Aesthetics of the radio as well as space, cost, and energy consumption of the head-end (servers, switches, routers etc.) is an additional concern for the building-owners, and we will discuss the importance of these factors in the next write up. Ensuring a highly-secure, flexible, scalable, and lowest cost in-building 5G ORAN are areas of focus for our team, and we are always looking at ways to do in-building networks better.

We encourage you to follow our blog as we will continue to share pertinent 5G ORAN thought leadership over the coming weeks.

Until then, stay safe and healthy!


Shirish Nagaraj leads technology development for Corning Optical Communications’ Wireless business unit, which delivers world-leading in-building cellular products for Tier-1 operators. He has been instrumental in conceptualizing, architecting, and developing the 5G mmWave small-cell system that is now deployed commercially at high profile stadiums, private enterprises, and other such venues. His team develops radio access network (RAN) and distributed antenna systems (DAS) software and hardware, with development centers in the US, Israel, and India.

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