Snowballing Complexity of Radio Systems Requires New Design Architectures to Meet Needs of Next-Generation Devices

Forefront RF, a fabless semiconductor startup company based in the United Kingdom, has unveiled patented tunable duplexer technology that has the capabilities to fundamentally change the way connected devices are designed. Officially trademarked and registered as Foretune, the company’s Radio Frequency (RF)-agnostic solution uses Adaptive Passive Cancellation (APC) technology (as used in noise-cancelling headphones) and is set to redefine mobile radio front ends in smartphones, smartwatches, and IoT devices by replacing fixed frequency filters with a tunable duplexer, simplifying software-defined radio systems design architectures. Forefront’s chip enables connected devices to operate across the increasingly wide range of multi-band devices from 3G to 6G, which will help reduce the need for model variants, thereby leading to environmental and economic benefits.

The adoption of 5G continues to thrive in the mobile market, with a raft of device types beyond smartphones set to form part of the wider ecosystem, extending to new industries and a wide array of device categories, including wearables, Extended Reality (XR), and Personal Computers (PCs). However, democratization of this extended 5G experience will be constrained, not just by the modem and application processor, but also by the growing complexity of the Radio Frequency Front End (RFFE). The transition to 5G has its challenges and requires not only new modems, but also improved radio system components, which includes more filters, smarter tuning, envelope trackers, etc., to help support performance through the addition of more spectrum bands, carrier aggregation, etc. This has brought with it a massive burden on the RF and a growing number of frequency ranges, which have led to an extensive increase in the number of components. Moreover, this problem has been exacerbated further by the need to provide multiple model variants of a single product due to a requirement to support different combinations of frequency bands as they vary from region to region, with some restricted to certain territories, while also catering to the needs of network operators.

The design and choice of appropriate RFFE components and modules has, therefore, become key for device vendors to differentiate their products, as it should make the task easier for them to develop devices more quickly and effectively, while addressing performance, added costs, and scalability. A particular approach taken has been solving the integration of the entire 5G cellular system design in their devices, from the antenna to the modem, which has been led by the availability of platforms from numerous companies and organizations, including Qualcomm, MediaTek, and members of the OpenRF consortium. However, the Forefront RF tunable duplexer solution brings another dimension to solving this complexity, as its APC chip replaces the requirement for banks of RF filters and switches with a low-cost, tunable RF circuit. This approach will not only result in condensing the overall die size area, but will also improve the procurement process, which has not yet been possible due to the limitation of current Frequency Division Duplex (FDD) filters and duplexers.

Importantly, the Forefront RF chip is future-proofed, which will become increasingly necessary as the mobile telecommunications industry is currently in the process of migrating to 5G-Advanced features, including Sidelink, enhanced Non-Terrestrial Network (NTN) support, and improved Reduced Capability (RedCap). These require additional new RF components and the support of new frequency bands, adding even greater complexity to the radio system with some necessitating the use of additional hardware. To make 5G-Advanced a success, huge collaborative work is required across multiple supply chains, including making the critical step from 5G Non-Standalone (NSA) to 5G Standalone (SA) networks to drive and derive benefit from the transition, and lay the technical foundations and accelerating the path toward 6G.

As the market continues its shift to 5G and beyond, the promise of sustained device and network enhancements all point to the use of technologies that are set to revolutionize RF design and drastically improve consumer experiences and use cases. It is important to push the industry toward grasping the fundamentals for resolving the snowballing complexity of integrating these advanced connectivity solutions, while learning lessons about cellular radio design and the growing need for designing these critical components differently.

Notably, while Forefront RF’s solution can deliver tangible benefits to vendors through streamlined manufacturing processes and reduced supply chain waste, it is also scalable across differing device types, software-defined, and future-proofed. By also layering on top its ability to reduce the number of device variants, thereby addressing the mobile industry’s drive to reduce e-waste and meet sustainability requirements, it all points to a compelling value proposition that fits well with the current industry narrative. It is believed to be in advanced discussions with several smartphone and smartwatch manufacturers and its Foretune chip is expected to feature in future product rollouts. The company’s challenge now will be to build an ecosystem that can thrive in the RF component sector, while working closely with those vendors that are currently entrenched in providing reference designs across a variety of devices.

Indeed, the RF companies that win out and gain industry support will need to demonstrate that their solution—in whatever form that takes—is able to improve performance, reduce time to market, lower overall costs, allow flexibility and customization, and reduce e-waste. Such metrics will become imperative for end-device differentiation, notably as the RF battleground extends into new sectors and markets beyond smartphones, as well as the impending shift to 5G-Advanced features and 5G SA. Moreover, under such a market environment, it is expected that many of these new use cases will be mission-critical, so the radio system must be near-perfect; otherwise, it jeopardizes their existence before they have even had the chance to get started.