Ronald Wilting, CEO of Forefront RF explains some of the reasons why.

A recent ABI Insight, written by Research Director, Dave McQueen, addressed the escalating complexities of Software Defined Radio Systems (SDRS) that have arisen in the wake of 5G going mainstream. The Insight also looked at how these challenges are being magnified with the advent of RedCap devices, poised to transform wireless deployments way beyond regular smartphones. In this blog, Ronald Wilting contemplates the complexity dilemma and explains how tunable duplexers the saving grace could be long-term.

Some background

The creation of the 5th Generation Network (5G) represented a landmark moment in the evolution of wireless communication technologies. Unlike its predecessors, 5G is the first mobile network to be developed with machines rather than people in mind, delivering low-latency and high efficiency data transfer speeds that are just not possible on earlier networks.

5G comes in different forms

The original 5G Network (3GPP Release 15), was non-standalone and relied on 4G infrastructure for the delivery of end-to-end services when 5G is not available. This is still the case today. 3GPP Releases 16 and 17 introduced a myriad of enhancements, such as innovations to support time-sensitive communication (TSC), a wider expansion of the 5G ecosystem, enhanced MIMO, small data transmission (SDT) and user equipment energy-saving capabilities to support automated technologies/applications at scale.

3GPP Release 18, otherwise known as 5G Advanced, however, is taking the wireless communications evolution to an entirely different level.  As well as including the latest enhancements in wireless technologies, 5G Advance promises to: allow more flexible and efficient spectrum usage, drive forward the RedCap phenomena and progress network topologies to enable seamless m2m communications, and provide data-driven, intelligent network solutions.

More bands  – more complexity in SDRS

As the different devices and capabilities underpinning IIoT, robotics, Industry 4.0 etc. come to fruition, global data usage is skyrocketing, and this is having a knock-on effect on the RF spectrum and the frequency bands used. Since the initial rollout of 5G, a proliferation of new frequency bands been made available across the low band, mid band, and high band frequency ranges. 5G Advance, along with the plethora of devices it is expected to support over and above regular communications devices will drive these increases further, with many geographical restrictions coming into play.

The journey to 5G Advance is also causing numerous challenges at device level

For starters, different modems, faster processors and low power batteries are needed for usability reasons. A more significant challenge, however, is the increased size and complexity of the mobile radio front end, which is the “beating heart” of all interconnected devices.

Corresponding advances in CMOS technologies in line with wireless RF developments have resulted in smarter baseband processors. The chips deployed in mobile front-end architectures, on the other hand, have not evolved to the same degree due to the physical limitations of fixed frequency filters. These components are integral to the very operability of all connected devices as they enable two-way communications. They also keep self-interference levels, (an unavoidable consequence of wireless RF) in check.

As more spectrum is made available to support an interconnected world, more filters, switches and other components are needed per device, something that is untenable long-term because PCB space in all mobile devices, including RedCap, is already at a premium. If frequency band allocations continue to escalate at current levels, applications such as health monitoring technologies, wearables, XR, cloud gaming, intended to run on these next generation devices will be severely hampered unless there is an overhaul in the chipsets used for SDRS.

End-to end 5G modules are not the answer

Some of the larger players are attempting to overcome the RF band dilemma by developing end-to-end 5G modules. But these solutions are not without its limitations because:

  1.  They are expensive to deploy
  2.  They don’t factor in legacy networks
  3.  They are not future-proof

As the wireless market continues its migration to 5G and beyond, the promise of sustained device and network enhancements all point to the need for components that will simplify RF designs without compromising enhanced user experiences and use cases. A possible solution is to leverage tunable duplexer technology, which is built to be versatile and adaptive, thus capable of supporting multiple frequency bands within a device’s operating range.

The concept of tunable duplexer technology is not new. Indeed, Imec researchers attempted to unveil the world’s first tunable duplexer at the ISSCC and MWC conferences back in 2015. Unfortunately, this initial prototype was susceptible to legacy noise and leakage challenges, which many semiconductor vendors are still struggling to overcome.

Overcoming legacy challenges for the very first time

Not Forefront RF though. Based on award winning research we’ve developed unique ForeTuneÔ Technology that resolves these interference challenges by leveraging self-cancellation techniques. Comparable to the way noise cancelling headphones improve noise rejection by listening to the surroundings, inverting said signal and adding it to the user’s soundtrack, Foretune™ dynamically cancels all unwanted high frequency signals emitted by transmitters and receivers in mobile radio front end designs by adding inverted versions of those signals.


With 5G advance paving the way for a new era of connected technologies and applications comprising AI and ML capabilities built in as standard, the race is on to resolve these historical challenges once and for all. The most compelling new use cases are likely to be dependent on time sensitive processing, so the SDRS, integral to the operability of these next generation services must be Gold Standard from the outset. If not, their chances of success will be seriously jeopardized before they have had a chance to take off.


Ronald Wilting. new CEO of Forefront RF