As RFFE design complexity magnifies, complications will arise when addressing issues of physical integration, standardization, and market penetration. System integrators need to prepare themselves to face these challenges.
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RF Component Approaches and Architectures Challenged as Mobile Moves to Next-Generation Networks
Until the deployment of early LTE networks, the design of the RF system was fairly simple and straightforward, involving a relatively small number of front-end components. However, the design of the RFFE has since become increasingly more complex with the upgrade to LTE-Advanced. These latest technologies have enabled 4G networks to become efficient and reliable through the use of carrier-aggregation (CA), MIMO, diversity, and envelope tracking.
In addition, the need to support a multitude of LTE bands in myriad combinations across the globe has amplified RF design complexity, leading to the addition of a greater number of RF components needed to support these bands and permutations. In the very constrained environment of smartphones, in terms of both energy and overall form factor, the RFFE system needs to be meticulously designed in order to optimize the overall performance of the device and mitigate interferences. This needs to be achieved without compromising the integrity of the device’s industrial design, reliability, and ability to support innovative features and functionalities.
RFFE design complexity is expected to magnify as the industry moves toward LTE-Advanced Pro and 5G. These networks will require additional RFFE functionalities, including higher order MIMO and massive MIMO, smart antenna systems, and sophisticated filtering functions, which add further complications.
RFFE Burden Is a Design Balancing Act
Despite the increases in complexity caused by these network upgrades, the physical RF footprint area on a smartphone has decreased through three main approaches:
Lowered Footprint Semiconductor Process: This development has enabled some discrete components to shrink over the past few years. For example, the use of new materials, such as gallium arsenide (GaAs) and silicon germanium (SiGe), has enabled power amplifiers to reduce in size.
Improved Packaging Technologies: New packaging technologies have enabled many RF components, including filters, duplexers, and multiplexers, to shrink substantially. These technologies also offer significant cost savings at the system level through reduced bill of material and simplified integration with other components.
Increased Physical Integration of Components: Integration and modularization of the main RFFE components, such as filters, PAs, duplexers, and switches, has continued apace. Many companies now supply these bundled solutions, such as Murata, Skyworks, Avago, EPCOS, Qorvo, and Qualcomm.
The concept of physical integration extends further with new packaged solutions that bring together a variety of components, such as PAs, switches, transmitter low-pass filters (LPFs), and receiver SAW filters, into front-end modules. While not all RFFE components can be subjected to bundling, due to their heterogeneous nature and interference, these newer types of integrated modules aid with lessening complexity further, while also reducing footprint size. Moreover, the increase in RFFE complexity and its associated hardware has a perceptible effect on smartphone industrial design. Handset vendors have to ensure that their devices are capable of integrating these high-end network technologies, and their RFFE requirements, into smartphones without compromising on time to market, price, performance, power consumption, or design. Any significant delays experienced by vendors’ smartphone models could prove disastrous, notably at a time when it is crucial for OEMs to remain competitive.
The use of standardized RFFE modules and help from end-to-end solutions providers will provide welcome support to OEMs, which will help greatly with the RFFE design process and speed time to market. It is patently clear that most handset vendors are currently struggling to cope with this increase in RFFE burden and no standard implementation has yet been pursued. In contrast to the OEMs, RF component manufacturers are under pressure to customize their products and comply with smartphone vendors and operators’ requirements, significantly impacting their overall margins.
RFFE Leadership Demands Component and System-Level Innovation and Integration
While the availability of comprehensive, high-performance RF components and modules is important, they have yet to fully reach mass market devices. Additional RF innovation will also be required to produce the next generation of mobile devices that will be packed with many new network technologies and features. As the market moves toward LTE-Advanced Pro and 5G, the physical integration of components will not be enough to address the RFFE challenge head-on, so a highly integrated RF system design will be key to aiding with this transition. Industry stakeholders must to grasp the opportunity to provide advanced RFFE system designs by providing not just the core set of RFFE technologies and advanced module integration, but also modem-to-antenna RF solutions. These high-end solutions will fulfill a need that the smartphone industry desperately craves, enabling OEMs to focus on customer experiences and deliver more reliable devices to scale and on time, negating their need to deal with a proliferation of future component types and suppliers.
The most likely breeding ground for these RF designs is system integrators, such as Qualcomm, Intel, Tsinghua (the holding company for Spreadtrum and RDA), Samsung, and Huawei, rather than the traditional RF component suppliers. Such an approach puts these types of companies in good stead to meet the upcoming challenges of 5G and will be a requirement for others along the supply chain if they are to survive. It is essential that they are able to provide smartphone vendors with the tools needed to create next-generation devices. During the next 12 months, key suppliers and systems integrators will increasingly absorb specialized vendors and some components suppliers, while competition may push some RF components vendors to exit the smartphone market altogether.
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