6G Realities: FR3,NTN, and the Rise of AI-Driven Networks

As the wireless industry charts its course toward 6G, the spotlight often falls on futuristic concepts like semantic communications and immersive XR, but for Kalyan Sundhar, Vice President and General Manager of Wireless Technologies at Keysight, the path to 6G is grounded in practical breakthroughs especially in spectrum, sensing, and artificial intelligence (AI). In a recent interview, Kalyan shared a pragmatic view of what’s emerging, what’s misunderstood, and what will matter most in 2026.

FR3: The Spectrum Sweet Spot

One of the most promising developments for 6G is the rise of frequency range 3 (FR3), which sits between FR1 and FR2. Kalyan sees FR3 as a critical enabler for 6G, offering a balance between coverage and capacity.

“FR3, especially the low bands, is gaining prominence. It moves the needle from 7 GHz upward and fills the gap between FR1 and FR2.”

Unlike sub-terahertz (sub-THz) bands, which remain largely in the research realm, FR3 is already seeing serious activity, but it’s not without challenges. Kalyan points to the massive antenna arrays required which will demand innovation in hardware, packaging, and power efficiency.

NTN: Ubiquity from the Ground Up

Another under-the-radar shift is the native integration of non-terrestrial networks (NTN) into 6G. While NTN was retrofitted into 5G, 6G will treat it as a first-class citizen.

“Ubiquitous coverage between terrestrial networks (TN) and NTN is going to happen more prominently from the outset.”

This seamless handoff between terrestrial and satellite networks will be essential for global connectivity, especially in remote and underserved regions. It also introduces new security and interoperability challenges, particularly as NTN intersects with open radio access network (RAN) architectures.

Sensing: Monetizing the Network

Kalyan believes sensing will be one of the most commercially viable features of 6G. From industrial automation to elder care, sensing opens up new use cases that go beyond traditional communications.

“Sensing is going to be an important one for monetizing 6G. It can open up things like object movement in factories, healthcare applications, and even defense.”

He highlights use cases like detecting subtle movements in elder care environments, enabling robotic coordination in smart factories, and enhancing situational awareness in military operations. These applications will require centimeter-level precision and robust integration with the communication stack.

AI: From One-Sided to Two-Sided Intelligence

AI is already transforming wireless networks, but Kalyan sees 6G pushing it further, especially into the physical layer.

“In 5G, AI was mostly on the base station side. In 6G, we’ll see AI enablement on both the transmit and receive sides.”

This shift to two-sided AI will require new models, training pipelines, and validation frameworks. It also raises questions about complexity, latency, and energy consumption. Kalyan emphasizes the need for careful trade-off analysis to ensure AI delivers real value without overwhelming the system.

Debunking the Waveform Myth

One of the biggest misconceptions about 6G, according to Kalyan, is the idea that it will introduce a radically new waveform to replace orthogonal frequency-division multiplexing (OFDM).

“The waveform is going to be OFDM-based. Numerologies may change, but the core waveform is fixed.”

This decision, made in recent 3rd Generation Partnership Project (3GPP) plenary meetings, streamlines the path to specification and avoids the delays seen in 5G. It also reflects a broader trend: 6G will be evolutionary in some areas and revolutionary in others.

Security: More Interfaces, More Risk

With 6G’s disaggregated architecture and expanded use of NTN, the attack surface is growing. Kalyan warns that researchers must prepare for new threats, especially those introduced by AI.

“AI has its pluses, but it can also bring real challenges with security. The more you train it, the better it behaves, but it can also be exploited.”

He sees AI as both a tool and a target, capable of enhancing security through anomaly detection but also vulnerable to adversarial attacks. The key will be training models to recognize and respond to threats in real time.

What to Watch in 2026

Looking ahead, Kalyan expects several key developments:

Conclusion: Building 6G from the Ground Up

Kalyan’s perspective reminds us that 6G isn’t just about futuristic visions, it’s about solving real problems with scalable, validated technologies. From spectrum and sensing to AI and security, the foundation for 6G is being laid now.

“We’re not dreaming about new waveforms as the baseline for 6G. We’re building on what works, and pushing it further with smarter spectrum, smarter sensing, and smarter networks.”

Listen to the full interview here.

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