Smartphone OEMs Need to Review Strategies for 5G RFFE System Designs

Components in smartphones that relate to the Radio-Frequency Front End (RFFE)—that is, that provide the link between the modem/RF transceivers and antennas—are expanding exponentially as the market embraces new network technologies such as Multiple Input, Multiple Output (MIMO) and Long-Term-Evolution- (LTE-) Advanced Pro. With 5G on the horizon, this market shows no signs of slowing down. It owes much to the host of multiple active radios and additional support of more spectrum bands and band aggregation required to make these technologies a reality while coping with more network functions and features (including beam tracking and beamforming) designed to enhance the user experience. The road map to 5G is proving even more complex and faster moving, and this brings with it a whole new raft of technical challenges.

As RFFE system design complexity has increased significantly, a host of new components are required each time a new generation of access technologies is introduced; 5G will be no exception. Indeed, frequency bands alone are set to reach over one hundred bands to facilitate these advancements on a global scale, and this will necessitate smaller footprints and better power efficiencies. To fully encompass all that is offered by the 5G standards, a smartphone will be expected to support a host of multiple bands and modes, have more complex carrier aggregation (CA), and aggregate the higher frequency bands available in 5G. With so much to be handled in a smartphone, the ability of Original Equipment Manufacturers (OEMs) to stick with a single global variant for their flagship products will be tested severely.

To address this complexity, many mobile industry players are looking to higher levels of miniaturization, integration, and performance to ensure that the design of a robust RFFE provides optimal trade-off between performance and power efficiencywithout compromising the industrial design and user experience. This will ensure that 5G can flourish unhindered, thereby unleashing the benefits that an enhanced network can bring for all along the value chain.

The use of highly integrated components—such as filters, Power Amplifiers (PAs), duplexers, and switches—and improved packaging technologies/modularization has (along with shrinkage) addressed some of this complexity. Advanced antenna-tuning techniques will now allow for a single antenna to be optimized over a large range of frequencies, thereby accommodating the expanding range of antennas in mobile devices that is expected from the launch of 5G. New manufacturing processes and materials have also helped OEMs to simplify and to accelerate handset design and development. In addition, the advent of band-group architecture has helped OEMs lessen the complexity of RFFE design while reducing footprint size and power consumption. Tunable filters might also be able to alleviate some of these design problems.

RFFE system design is currently the remit of OEMs and has long been a key differentiating factor, as it has been tightly correlated with the overall industrial design of the phone. Smartphone vendors procure different components from heterogeneous manufacturers with the aim of taking advantage of the highly competitive RFFE landscape to reduce reliance on a single supplier across their portfolio. However, when making these choices, OEMs need to take ownership of RF design while ensuring that it has a minimal-to-no impact on industrial design and that both performance and power consumption are not compromised.

Currently, no one RFFE supplier dominates the smartphone market in any component category. However, companies such as Qorvo, Skyworks, and Qualcomm all have content that can be found in most major smartphone models and offer the broadest range of RFFE products. Of significance is the inclusion of Qualcomm—as it is known mostly for its large-scale integrated chipsets and modems—in this short list alongside RFFE stalwarts Qorvo and Skyworks. Qualcomm has taken a big step forward in the RFFE arena, not just with acquisitions (e.g., TDK/Epcos) but also with its internal design expansion (e.g., PAs). Other RFFE suppliers such as Avago and Murata thus far seem content to focus on particular component types owing to a lack of a more complete product portfolio.

Some serious work is needed by the industry to provide cogent solutions if the 5G smartphone market is not to stall. Indeed, most smartphone vendors have struggled to cope with the substantial increase in RF burden because of LTE—let alone what is expected of 5G. Incorporating this new raft of components and support for a widening band of frequencies into 5G devices over the next couple of years will be critical to making the transition a success while minimizing the impact on price and industrial design. It is the suppliers’ mission to come up with new modules and solutions to counter these issues.

Generally, RF component supply is a crowded market, and, while there has been some consolidation already, more is surely imminent with modularization a key differentiator. Moreover, the transition to 5G means that OEMs need to make huge investments in RF competencies and system expertise in mobile broadband and RF technologies. The higher frequencies of 5G creates more opportunities in terms of RF solutions and RF design, but only those following these technologies and capabilities as part of a 5G road map will survive. This will require significant investment in RF know-how. If the industry does not act quickly and provide some much needed rationalization and integration at the RFFE, then it faces some serious challenges over the coming years.

Of the current RFFE suppliers, ABI Research believes that Qorvo, Qualcomm, and Skyworks will stand out as most likely to succeed in the 5G RFFE market. These players are well positioned to thrive not only due to their current RFFE module experience but also due to their antenna-tuning portfolios flowing directly into the needs of the 5G RFFE module (which includes the antenna). Of consequence is whether Qualcomm’s additional portfolio of transceivers and modems will give it any additional advantages over other RFFE competitors.

While a modem-to-antenna-packaged solution (as supplied by Qualcomm) is one way forward for the OEMs—mainly attracting those with small- to medium-scale production—such an approach will not resonate with all OEMs. This packaged solution takes away the burden of designing RF systems, enabling products to reach the market faster. However, those OEMs operating at a large scale (i.e., generating large shipment volumes across few model Stock Keeping Units, or SKUs—most notably Apple) are more likely to want to retain ownership of their RF reference designs. Keeping ownership is vital for two main reasons:

1. OEMs gain more flexibility through customization in placing various RF components across the whole device PCB to minimize the impact on industrial design and to maximize the overall performance and power efficiency of the device.
2. The ability to produce large-scale flagship devices means having better control of RF procurement while negotiating better deals, thereby taking advantage of the highly competitive nature of the market. In this instance, RF suppliers are often asked to customize components in line with well-defined specifications for use on a plug-and-play basis without compromising the device industrial design.

RF component suppliers are therefore happy to customize for these types of OEM because of their large-scale procurement. Conversely, smaller OEMs have no option but go with off-the-shelf or packaged RFFE components and modules as recommended by their main reference design suppliers. However, some Chinese OEMs—notably OPPO, Vivo, and Xiaomi—that do produce large-scale shipments but from a greater number of models mainly differentiate their smartphones on price, and so they cannot necessarily afford to use this level of customization and turn to more cost-effective packaging or off-the-shelf solutions.

This flexible approach has been borne out by Intel when it announced its XMM 8160—the second generation of its 5G NR offering, which comes in the form of an integrated 2G/3G/4G/5G modem, 5G sub-6 GHz RF transceiver, and a 5G transceiver for mmWaves. Although Intel’s integrated 5G modem provides the industry with a fully optimized solution, it has limited experience in RFFE components that will need to be addressed. Here, Intel’s approach is to bridge the gap among modems, transceivers, and antennas using a co-optimization framework with suppliers to address this inherent RF complexity without compromising on smartphone time to market, price, performance, and power consumption. Moreover, with Apple included as a likely customer, Intel should be able to use this as leverage to scale, to effectively manage, and to overcome the challenges that RF poses so that they can command some highly integrated RFFE components for 5G. This scenario is likely to be followed by Huawei, Samsung, and MediaTek, who all produce modems andprovide RF transceivers across their high-end portfolios and who provide reference design procurement and customization for the RFFE. Alternatively, Samsung, Spreadtrum, and MediaTek might follow with the same antenna-to-modem strategy as Qualcomm, but this would require acquisitions of firms who already have the know-how to provide it.

Smartphone OEMs have to ensure that their devices are capable of integrating innovative technologies brought about by LTE-Advanced Pro and 5G without compromising the efficiency of their RFFE system designs and device form factor. To achieve this goal they will have to rationalize their RFFE component procurement to a handful of suppliers and, most importantly, make sure they pick the right partner—one with a rich RFFE portfolio and a strong 5G road map. Moreover, component suppliers will themselves fall into one of two camps—providing customization of components and modules for large scale OEMs in line with their requirements or providing off-the-shelf components and modules. Taking the latter path sees suppliers integrating a number of RFFE functions into a single package so as to minimize the overall footprint and enhance performance and power efficiency. Integration is a key differentiator in this market because it provides much needed flexibility to OEMs and reference design makers who are then able to easily integrate these solutions into their industrial designs and therefore accelerate the product time to market.

It is this ability of RFFE component suppliers to provide the smartphone ecosystem with a complete solution that will enable OEMs to deliver mobile products at scale and on time, lowering their overall development costs. During the transition to 5G, time to market will be crucial for survival to many along the mobile value chain. 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 road map will survive—and this indicates the need for significant investment in RF expertise.