Integration between 5G and Legacy Air Interfaces Is Key to Providing Superior Optimized Radio System Designs in Smartphones

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By David McQueen | 4Q 2020 | IN-5981

OEMs would be wise to address radio system designs now to meet the challenges 5G brings to mobile device design. OEMs need to adopt modem-to-antenna system design practices, offering leadership when it comes to modem and RFFE components to remain competitive in the 5G landscape.

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Smartphone Radio System Consolidation across Technologies Is Vital to Drive Wider 5G Adoption


As the smartphone market continues its speedy transition to 5G, it is becoming increasingly obvious that the design of Radio Frequency (RF) systems and the choice of appropriate RF Front End (RFFE) components will become fundamental differentiators, not just for 5G, but also for legacy air interfaces, including Long Term Evolution (LTE). Such an approach will enable Original Equipment Manufacturers (OEMs) to efficiently and cost-effectively integrate 5G with 3G/4G into complex form factors.

Fast-Growing 5G Market Demonstrates Increasingly Complex Challenges for Smartphone OEMs


The 5G smartphone market is now outperforming its predecessor generations, including LTE smartphones, on nearly every metric, including the number of mobile devices, subscribers, and networks available at launch. However, 5G brings with it a number of technical challenges, features, and functionalities, as well as new radio elements for supporting new radio bands and combinations, all of which can lead to substantial changes in the design of mobile devices. OEMs will be increasingly challenged under this new landscape and could run the risk of lengthy product development cycles and more expensive devices if they do not adequately address the design complexity they are faced with, notably at the radio system level.

This level of complexity is not just the preserve of the high-end, as the availability of 5G smartphone models will become more diverse, brought to market quickly at a wide variety of price points, democratizing the 5G experience. Indeed, with many leading OEMs expected to push deeper into the lower-priced 5G smartphone segment, mid-range smartphones will be the main driver for accelerating adoption throughout the year and into 2021.

Solving the RFFE burden that complexity is putting on devices is becoming paramount for the leading OEMs and it is now manifest in a number of different ways, chiefly:

  • Handling the increasing numbers of RFFE components brought about by myriad 5G frequency bands and configurations, as well as by new features that are necessary for 5G functionality
  • Ensuring integration with 3G/4G RFFE components to provide optimized configurations, but also to provide better support for new functionalities, such as Dynamic Spectrum Sharing (DSS), 4G-5G Carrier Aggregation (CA), global 5G/4G band support, and global multi-Subscriber Identity Modules (SIMs)
  • Signs of a growing mmWave ecosystem bringing additional layers of complexity

The trend of OEMs adopting 5G-integrated system designs from modem-to-antenna is becoming noticeable. Such a strategic approach has been considered by few component suppliers in the market, thus far, with Qualcomm taking first-mover market advantage, but the approach has been well received by a number of OEMs, whether for support of 5G in sub-6 Gigahertz (GHz), mmWave, or both.

While this is one area of complexity that appears to have been addressed, even if by just one supplier thus far, attention in the industry has now turned to solving the entire RFFE, and it is set to be a major growth opportunity from 4G, 5G, sub-6 GHz, and 5G mmWave content. While it is expected that third-party modem-RF system design will become a mainstream approach in support of many of the world’s top smartphone OEMs to solve their 5G conundrum, the ability to take control of all aspects of the RF is the next obstacle to be overcome if they are to reap the enormous benefits.

Smartphone OEMs Need to Rationalize 5G and Legacy Air Interface RFFE Procurement


As the entire RFFE, not just with respect to 5G, becomes one of the key drivers of revenue growth in the components industry, it will become a fertile landscape. 5G smartphone sales are expanding rapidly, so the RFFE is now set to replace the modem/chipset as the largest revenue growth opportunity in the industry. It is expected that the vendor landscape will change rapidly in 2021, as lead suppliers jostle to seize market share. However, there are signs in the industry that this approach has been expanded to encompass an optimized design that now includes 4G. OEMs can now no longer afford to separate 5G from support of previous network technologies when it comes to rationalizing RFFE procurement.

There needs to be tighter integration and an optimized design, which cannot be ignored by OEMs when looking to rationalize RFFE procurement. Moreover, it ensures that OEMs’ devices can address the following:

  • Integrating all network technologies without compromising the efficiency of RFFE system designs and device form factor
  • Removing the intricacies involved in component sourcing across all technologies, simplifying the complex component RF sourcing involving many suppliers
  • Accelerating smartphone development and time-to-market, enabling OEMs to save both time and money by bringing 5G multimode devices to market in a timely manner
  • Providing tight collaboration between LTE/4G and 5G components for new features, notably 5G/4G EN-DC, CA, DSS, and global multi-SIM to function effectively

A combination of the supply of components from modem-to-antenna in future 5G models and the ability to integrate 3G/4G will markedly influence OEMs’ decisions when choosing suppliers to use across all technologies. Market success gained in 5G RFFE, as well as that for modems and application processors, is already starting to have a profound effect on the future use of related legacy components. This integration will have a significant bearing on future devices because suppliers that do not have a strong 5G footprint will be susceptible to losing traction they may otherwise hold with LTE/4G. Far from being a one-off activity, this trend toward OEMs using a single supplier for 5G and 4G, notably as innovative features are introduced, will become the norm and, as the first mover, Qualcomm is currently the standout candidate to offer this level of solution.

The stark reality is that as OEMs delegate the RFFE to a third party without compromising the efficiency of the RFFE system designs and the overall device form factor, if they were to wait for other solutions to offer anything approaching Qualcomm’s level of integration, they could face a lag of 2 to 3 years, losing time-to-market and, consequently, market share. However, the formation of the Open RF Association (OpenRF), an industry consortium dedicated to expanding the functional interoperability of hardware and software across multi-mode RFFE and chipset platforms, could create a welcome alternative for the OEMs. The OpenRF includes companies like muRata, Qorvo, Skyworks, and MediaTek, and will provide a combination of options for OEMs to select optimal, integrated components to potentially lower costs, improve performance, and reduce time-to-market. However, this may still lengthen the development time to compile solutions for the OEMs, while potentially complicating a procurement process involving collaborations with multiple suppliers.

Other solutions providing radio system consolidation across technologies are likely to appear in the coming years, as there is no longer a separation between 5G and legacy RFFE technologies. However, the rapid growth of 5G smartphones means they will have to move fast, and whoever commands an end-to-end solution will rule the market, eating up market share in the process. Moreover, modem and RFFE leadership will be critical under the 5G landscape, and only those following these technologies and capabilities as part of a 5G roadmap will survive.



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