Sadayuki Abeta

Global interest continues to grow regarding Open RAN, which uses open and standardised wireless base-station specifications to enable the devices and systems of multiple telecom vendors to be interconnected in mobile networks. 

However, operators constructing networks incorporating devices from just a single vendor are now facing technical and verification challenges in their efforts to implement Open RAN. Today, NTT DOCOMO is leveraging its expertise to support the Open RAN efforts of operators worldwide.

Earlier in 2023, DOCOMO adopted the OREX (Open RAN Ecosystem Experience) brand to strengthen the support scheme for international telecom operators in delivering the Open RAN system.

“OREX provides the Open RAN solution, creating a new network experience that is truly open to the world,” explains Sadayuki Abeta, NTT DOCOMO’s Global Head of Open RAN and OREX Evangelist. “OREX is committed to making 2023 the defining year for Open RAN. Our ultimate goal is to eliminate global communication gaps through the OREX initiative.”

NTT DOCOMO is the number one mobile operator in Japan. Having launched its first-generation service in 1979, since then the company has pioneered new technologies. 

Today DOCOMO has three business segments: enterprise, smart life, and telecommunications. It has 87m subscribers, with 20m subscribers enjoying its 5G Open RAN services, with a total revenue of around US$44bn.

An expert in the mobile industry for more than 25 years, Abeta’s career at NTT DOCOMO started as a researcher for 4G in 1997. 

“My career at NTT DOCOMO started as a researcher for 4G in 1997,” he explains. “Then, we brought our ideas to 3GPP and I participated in 3GPP standardisation from 2005. 

“With 3GPP, I served as the Vice Chair of 3GPP RAN1 and the rapporteur of LTE and LTE-A. After the completion of the LTE standard specification, I led the development of eNB and gNB commercial products and network optimization in the commercial network as the General Manager of the Radio Access Network Development department.”

In 1997 the second-generation mobile system was introduced in Japan. Instead of GSM, Japan utilised the Personal Digital Cellular (PDC) system. “During this time, data services over the mobile network were initiated, but the data rate was incredibly low, starting at only 2.4kbps,” Abeta explains. “It's hard to imagine today, but at that time, only small text messages could be transferred over the mobile network. Eventually, the data rate increased to 28.8kbps.

“In 1999, we launched the i-mode service, marking the beginning of internet services over the mobile network.”

In 2000, 3G was introduced, with DOCOMO playing a significant role in contributing to the 3GPP standard specification work. “We led technical discussions and managed the discussions as one of the officials, serving as the Chair. We were the first operator to deploy 3G networks nationwide and provided rich content via the 3G network. However, the data rate was still limited to 64Kbps or 384kbps. Later, HSPA technology was introduced, enabling much higher throughput.

“Moving forward, we proposed LTE together with our partners and launched 4G services in 2010,” Abeta describes. “Our 4G radio access network (RAN) was fully multi-vendor interoperable. We defined interfaces that were not initially defined by 3GPP, making us the first operator to deploy a multi-vendor interoperable RAN. The rise of smartphones in conjunction with our 4G services revolutionised the user experience, and its benefits are well-known.”

While DOCOMO’s communication services continued to thrive, the company also expanded its non-communication services, evolving into the smart-life service segment.

When it comes to the rollout of 5G, DOCOMO has contributed not only to 3GPP but also to the O-RAN alliance to realise multi-vendor interoperable Open RAN solutions. “In 2018, we established the 5G Open Partner Program, aiming to create new services and address social issues by collaborating with vertical players,” Abeta adds. “Currently, this program has attracted participation from 5,300 companies and organisations.”

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