Keysight’s chief technologist on the path to 6G

The transition to 6G mobile networks is poised to redefine the telecom landscape, necessitating a shift beyond merely faster access speeds. As the industry prepares for the deployment of commercial 6G networks by 2030, it will need to address the increasing volume of artificial intelligence (AI) traffic, integrate non-terrestrial networks (NTNs), and importantly, tap into the enterprise market. Balaji Raghothaman, the chief technologist for 6G at Keysight Technologies, recently shared insights on these challenges and opportunities during an interview at the 3GPP’s inaugural plenary meeting in Singapore.

Raghothaman emphasized that the telecom sector must adapt its business models to avoid becoming mere conduits for AI traffic, often referred to as “dumb pipes.” He highlighted the importance of learning from the past, specifically the experience of telecom operators during the rise of the app economy in 4G and early 5G, where they lost value to other players in the ecosystem. To counter this, some innovative operators are exploring concepts like AI-RAN (Radio Access Network), which involves sharing server resources to manage RAN traffic and run AI workloads, thereby creating new business opportunities.

The Shift in Spectrum Focus

Initially, the discussion around 6G included the potential use of sub-terahertz spectrum, but Raghothaman noted that interest in this area has waned significantly. The limited range and high deployment costs associated with sub-terahertz frequencies have led to a consensus among operators to focus on existing frequency ranges, specifically FR1, FR2, and FR3 bands. The aim is to deploy 6G with a footprint similar to the existing 5G C-band, which operates around 3.3 GHz to 4.2 GHz, while also expanding into FR3 bands, which range from about 7 GHz to 24 GHz.

This transition to higher frequency bands presents significant challenges. The increased frequency results in higher propagation loss and reduced coverage. To address this, operators will need to deploy a greater number of antennas to achieve beamforming gain. Raghothaman pointed out that while 5G networks typically utilize 64 to 128 antennas, FR3 networks may require 256, 512, or even more antennas. This necessitates the design of new radios that do not exceed power budgets, as the energy-per-bit could increase with the deployment of FR3.

The Role of Non-Terrestrial Networks

The integration of non-terrestrial networks is another critical aspect of the 6G roadmap. Raghothaman explained that coexistence issues arise when NTNs overlap with terrestrial spectrum, necessitating careful planning to ensure seamless operation. Additionally, the speed of satellites, which move at thousands of kilometers per hour, presents a challenge for baseband receivers that must accommodate the significant delays and Doppler effects associated with satellite communication.

Despite these challenges, Raghothaman noted that satellites are essential for achieving near-100% coverage, particularly in remote regions where maintaining terrestrial towers is economically unfeasible. He discussed two types of satellite implementations: pass-through, which merely relays signals, and regenerative, which processes data. The latter is particularly advantageous for AI inferencing, as it allows for improved user experiences by processing data closer to the edge.

The Enterprise Market and Indoor Solutions

As the mobile industry evolves, there is a renewed focus on enterprise solutions. Raghothaman pointed out that while enterprises often gravitate towards Wi-Fi due to its ease of deployment, cellular networks must find ways to compete effectively. Traditional cellular network planning has been predominantly outdoor-focused, but advancements in tools like ray tracing and digital twins are enabling more precise indoor network designs.

With the ability to create geometric digital twins of buildings, operators can leverage AI-powered network optimization to tailor network designs to specific locations and usage patterns. If cellular providers fail to address indoor network challenges, they risk losing significant enterprise market share to Wi-Fi.

Raghothaman also highlighted the ongoing efforts within 3GPP to explore integrated sensing and communication, while cautioning against overpromising on new use cases. The technical challenges associated with sensing technologies must be addressed to maintain trust in the technology. As operators seek new monetization avenues beyond flat-rate subscriptions, services like drone detection or elder care monitoring present potential revenue streams.

Finally, Raghothaman discussed the regulatory landscape, noting that traditional spectrum harmonization efforts are ongoing. However, the rise of AI introduces new regulatory challenges, particularly concerning the certification of AI-driven devices. As the telecom industry navigates these complexities, Keysight’s role will be to provide the necessary measurement and data to ensure safe and effective deployment of 6G technologies.

In summary, the path to 6G is fraught with challenges, but it also presents significant opportunities for telecom operators willing to innovate and adapt. As the industry gears up for this next generation of mobile technology, understanding these dynamics will be crucial for creators and technologists alike.