Going forward, cultivating pioneering and adaptable talent will be more essential than ever.

Fumio Watanabe , Ph.D(Engineering)
Institute of Science Tokyo
Academy of Super Smart Society
Super Smart Society Promotion Consortium
Specially Appointed Specialist / Promotion Advisor

Until the 4G era, advances in mobile communications technology largely drove society’s needs. With 5G, however, the situation looks markedly different. We spoke with Dr. Fumio Watanabe—who has long been at the forefront of mobile communications and has also dedicated himself to training the next generation—about his expectations for a Beyond 5G society, the prospects for international standardization, and the direction Japan should take.

A Necessary Shift to Align with Society’s Needs and Wants

Looking at the potential impacts of a Beyond 5G-enabled society and the world it will shape, which domains do you view as particularly important or promising?

Watanabe:
When we talk about “G-generations” such as 5G or Beyond 5G, the discussion often centers on technical differences such as higher throughput, lower latency, or massive connectivity. Here, however, I would like to offer a distinct perspective.

Mobile communications originally served person-to-person communication, but, in the transition from 3G to 4G, it evolved into a system connecting people to servers, for example, for accessing Internet-based services. It then expanded to communication between machines and servers, and even machine-to-machine communication, giving rise to the Internet of Things (IoT). That is an essential hallmark of 5G.

Looking ahead to Beyond 5G, the most critical domain will be AI-to-AI communication. The network itself will function as a “Network for AI.”

The original goal of mobile communications allowing anyone to communicate with anyone else anytime and anywhere has already been achieved. But future development will not simply extend this trajectory. Until recently, mobile communication technology has guided society’s needs. It has progressed based on a provider-driven logic, and that approach is now reaching its limits. We are at a stage that demands a qualitative shift toward a direction that meets the needs and wants arising from today’s social challenges and conditions.

The Ministry of Internal Affairs and Communications envisions realizing Beyond 5G in the 2030s. How do you view the current situation?

Watanabe:
Up through 5G, progress occurred roughly every decade, and stakeholders set goals primarily around advances in wireless transmission technologies. When the international 3G standard was finalized in November 1999, I was serving as vice-chair of the working group. Around 1990, we set the 3G target data rate at 2 Mbit/s, and many argued it was unnecessarily high. Yet once 3G spread, demand for high-speed communication surged rapidly. We learned that if we provide powerful tools, use cases emerge afterward.

An analogous situation occurred with 4G. As communication speeds increased ten-fold to a hundred-fold, society transformed into one where nearly everything is conducted via smartphone. Up to that point, development was still led by the provider’s logic.

But 5G is different. We also set ambitious targets for throughput and latency for 5G, and companies are now applying the technology, for example, in the remote control of heavy machinery and in remote surgery. Even so, it has not yet produced what people would unmistakably call a transformative 5G experience. Deploying nationwide mobile coverage requires massive upfront investment, yet viable pathways to monetizing the unique capabilities of 5G remain unclear.

This suggests that applying the same provider-driven approach to Beyond 5G will lead to an impasse. Rather than asking what technologies we want to realize in the 2030s, we must instead ask:

• How should technology meaningfully serve society?
• What new industries can we create?
• Ultimately, how do we enhance human well-being?

We need to invert the traditional way of thinking: first envision society in the 2030s, then determine what infrastructure is required to support that vision.

For example, we might define a societal goal such as achieving a zero-accident transportation system by year XX and then develop a set of technological milestones aligned with that objective.

Bolstering Software Capabilities

What is your assessment of Japan’s technological standing for Beyond 5G?

Watanabe:
Japan remains world-class in fields such as optical devices and optical transmission, particularly at the research level. Building on such strengths, we must also examine the areas where we are weak.

Today’s network systems are predominantly software driven. A useful analogy comes from the automotive sector. Traditionally, automobiles were mechanical systems supplemented by computers to enhance safety and convenience. With the rise of battery-powered electric vehicles, this has reversed: vehicles are becoming mechanically simpler, and the conceptual shift is toward putting a car body around a computer.

Communication networks are evolving in the same direction. In the past, equipment had to differ when frequencies differed, but that is no longer the case. Today, even if the wireless transmission method changes, a certain level of adaptation is possible simply by modifying software. What is important in software is not so much programming itself but rather the operating systems and architectures that underpin software functionality. Architectural design is key, but Japan is weak in this area.

Physical products can never achieve zero marginal costs, but software can simply be copied, so its cost asymptotically approaches zero. Competing against players who build their business models on this paradigm using a hardware-centric mindset is extremely difficult.

Another critical element is AI. In the future, there is no doubt that wireless transmission, the backbone, fiber transmission, the core network, network operations and maintenance, and service delivery will all be AI driven. Around the world, intense competition is underway around AI for Network. Wireless systems are shifting from hardware-based radios to SDR (Software-Defined Radio) and eventually to AI-Defined Radio, and similar transitions are expected across the network and service layers.

AI development depends heavily on the volume of training data and the computational resources available. It is, in a sense, an endurance contest. Countries and companies with limited financial and data resources will inevitably fall behind. Japan is making significant efforts, but the environment remains challenging.

To summarize: the critical challenges are software and AI. Conversely, if Japan strengthens these fields, it can compete on equal footing globally and potentially gain strategic advantage.

The Shifting Landscape of International Standardization

What challenges do you foresee for international standardization of Beyond 5G?

Watanabe:
The United States generally prefers de facto standards—those formed through market dominance rather than consensus. Europe, with its many countries, often prefers de jure standards created through formal standardization bodies.

In the 2G era, wireless systems and frequency bands differed across the U.S., Europe, and Japan, meaning mobile devices often did not work abroad. From 3G onward, global standardization ensured interoperability worldwide.

Beyond 5G, however, poses new challenges.

First is the concept of “generations.”

Technologists often imagine a revolution—a leap from one generation to the next. It is the mission of researchers and engineers to change society with revolutionary technology that is completely different from the past. Indeed, up through 4G, the generational shifts were revolutionary. Yet it should be noted that we also dubbed 4G “LTE: Long-Term Evolution,” signaling an intention toward gradual, evolutionary progress.

For 5G, however, the mindset reverted to pursuing a revolution and generational shift. As mentioned earlier, this has resulted in difficulties: despite enormous capital investments, 5G has not yet transformed society at scale. Therefore, I believe Beyond 5G should follow a long-term evolutionary path, especially since many wireless functions today can be altered simply through software updates. We should aim for evolution with backward compatibility—while recognizing that a revolution may eventually be required.

Second, as noted earlier, the keywords for Beyond 5G are Network for AI and AI for Network. Yet AI systems are often black boxes, lacking transparency. Standardizing networks deeply infused with AI is thus extremely challenging. In some scenarios, formal standardization may prove impossible, leading to a de facto situation where superior implementations dominate.

What are your expectations or concerns for industry-academia-government collaboration?

Watanabe:
I have strong expectations for such collaboration, particularly for international joint projects.

To achieve outstanding outcomes, the way we write requirements when soliciting project proposals is important. It may sound paradoxical, but we must clearly articulate the direction of the society we aim to build while avoiding constraints that narrow proposers’ creativity.

Technology and institutional design, including legal and regulatory frameworks, are two wheels of the same cart, and they must progress in synchrony.

What do you consider key for advancing Beyond 5G research and development?

Watanabe:
Ultimately, R&D and international standardization depend on people. Even as AI evolves and efficiencies rise, human judgment and creativity remain decisive. It is therefore the responsibility of society and educational institutions to cultivate people with broad international perspectives and the ability to think both boldly and flexibly.

Recently, we held a hackathon using AI, with mixed teams of students and business professionals. They inspired one another greatly. I feel that Japan has not yet done enough to create environments where such mutual stimulation can occur. Japan should place much greater emphasis on activities grounded in openness and inclusivity.