Conventional Radio Access Network (RAN) has been based on a closed and vertically integrated architecture in which all components consist of the same vendor equipment. Recognizing that in the 5th Generation Mobile Communication System (5G) era, there is a need for a more scalable and flexibly deployable network, as well as for improved communication performance, the awardees have proposed and promoted a conceptual shift to an open and horizontal division of work that enables the selection of different vendor equipment for each RAN component. (Figure 1)

In order to implement the concept, in February 2018 they established the O-RAN ALLIANCE (O-RAN), an industry organization that aims to make RAN more open and intelligent, in cooperation with mobile phone operators around the world, and have taken the lead in standardization(1). Further, in February 2021, they launched the 5G Open RAN Ecosystem(2) in cooperation with global vendors(3) with the aim of expanding Open RAN worldwide; in February 2022, they established Shared Open Lab that enables remote verification of virtualized base stations from overseas(4); in October 2022, they reached an agreement with Vodafone Group PLC to promote Open RAN(5) (a joint white paper on integration issues and service operations / orchestration issues was then published); and in September 2023, they announced the OREX® service lineup, which can reduce TCO by up to 30% and power consumption by up to 50%(6). In such ways, they have been leading the world in opening up RAN. (Figure 2)

Further, the awardees were the first in the world to successfully interconnect multi-vendors’ 5G base station equipment based on O-RAN specifications, and NTT DOCOMO launched a 5G pre-service employing the O-RAN ALLIANCE’s equipment interoperability interface specifications in September 2019(7). In March 2020, NTT DOCOMO launched its commercial 5G service, and in September 2020, it became the first company in the world to commercialize the 5G frequency Carrier Aggregation in multi-vendor RAN(8). In addition, in August 2022, it launched a 5G SA commercial service with maximum data rates exceeding 1 Gbps for both transmission and reception(9), and in September 2023, it started the commercial operation of virtualized base stations (vRAN) and RAN Intelligent Controllers (RIC), leading the spread and expansion of O-RAN specifications. (Figure 2)

With such expansion of the opening up of RAN, selecting RAN components from different vendors became possible. This allows for greater flexibility in functional expansion, cost savings through increased competition, and avoidance of supply chain and geopolitical risks. It also allows for greater transparency to ensure security.

References

1. NTT DOCOMO Technical Journal Vol.22 No.2 (Oct.2020) NTT DOCOMO Contributions to 5G Standardization
2. 5G Open RAN Ecosystem Whitepaper, 28. June.2021
   https://www.nttdocomo.co.jp/corporate/technology/whitepaper_5g_open_ran
3. NTT DOCOMO Press Releases (2021.2.3): Creation of "5G Open RAN Ecosystem" to Accelerate Open RAN to Operators Globally
4. NTT DOCOMO Press Releases (2022.2.28): DOCOMO Opens vRAN Verification Facility to Global Mobile Operators -Remotely accessible lab will help operators lower 5G base station deployment costs-
5. NTT DOCOMO Press Releases (2022.10.25): Vodafone and NTT DOCOMO sign MoU to cooperate to drive greater system integration and service efficiency in Open RAN
6. NTT DOCOMO Press Releases (2023.9.27): OREX Announces OREX® Open RAN Service Lineup
   -Achieves TCO reduction of up to 30% and reduces power consumption by up to 50%-
7. NTT DOCOMO Press Releases (2019.9.18): DOCOMO to Commence Deployment of World's First 4G/5G Multi-vendor Radio Access Network Conforming to O-RAN Specifications
   Facilitates multi-vendor interoperability, which will drive expansion of 5G coverage
8. NTT DOCOMO Press Releases (2020.9.30): Expanded Lineup of 5G Base Stations using O-RAN Specifications
   Realized multivendor connectivity with new CU/DU in DOCOMO commercial network environment
9. NTT DOCOMO Press Releases (2022.8.23): Launched 5G SA for Smartphones