Taking the Complexity out of LTE Radio Front End Designs · 2018. 7. 23. · Taking the Complexity...
Transcript of Taking the Complexity out of LTE Radio Front End Designs · 2018. 7. 23. · Taking the Complexity...
Taking the Complexity out of LTE Radio Front End Designs Qualcomm offers Smartphone OEMs Pre-Baked RFFE Solutions
July 23, 2018
TMT - Wireless Semiconductors | White Paper
Wayne Lam Director and Principal Analyst
IHS Markit | Title of Report
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Taking the Complexity out of LTE Radio Front End Designs
Qualcomm offers Smartphone OEMs Pre-Baked RFFE Solutions
Wayne Lam, Principal Analyst
As the smartphone industry passes its decade-long run being the most popular consumer electronics of all time, the
market is beginning to see signs of maturation and slowdown. Smartphone OEMs are now competing on
innovations in form factor (i.e. the move to larger and bezel-less displays), cameras (i.e. biometric sensors and
computational photography) as well as Artificial Intelligence (AI) services; trading slender technological leads from
one flagship launch to another. However, one area of innovation that is crucial for OEMs to keep up with is LTE
radio design; especially the evermore complex RF Front End as wireless carriers continue to evolve and advance
the 4G standards with features like carrier aggregation, higher order modulation, and use of 4x4 MIMO (downlink)
throughout their networks.
The LTE radio design of a smartphone is rarely talked about as a key selling point of a new flagship smartphone as
consumers simply expects it to work better than the previous model. The RF Front End (from the antenna to the
transceiver) is an ever-changing design of the modern smartphone riddled with complexity. In fact, the RF Front
End (RFFE) is the only section of the smartphone design that is growing in the amount area it occupies on the main
printed circuit board (PCB) of modern smartphones while board space for other electronics are shrinking over time.
It is exactly this complexity that is enabling the advancement of LTE wireless speeds in every new flagship design
as it makes more and more efficient use of the limited LTE spectrum available to the user.
In this whitepaper, IHS Markit will explore the factors leading to the ever-increasing complexity of a LTE RFFE,
which directions leading handset OEMs are going to keep up with the RFFE complexity inflation and what solutions
are available to OEMs – especially the smaller ones, i.e. Tier 2 players – to keep up with competitive designs.
Further, leveraging findings from recent IHS Markit teardowns, we will investigate the latest LTE Category 18
designs from four different OEMs utilizing a varied spectrum of RFFE solutions from Qualcomm. This finding is
significant as this level of vertical integration represents an industry first, a RFFE solution from modem to antenna
made by one component vendor. In addition, we will discuss how this new approach to taming the RFFE complexity
can enable smaller OEMs to compete effectively with larger OEMs with dedicated RF design capabilities leveling
the playing field for a market dominated by just a few brands.
LTE = Long Term Evolution
LTE is arguably the most successful wireless standard ever purposed for mobile communications in terms of
adoption. As the name implies, LTE is designed to evolve and scale over time both in speed and capacity. To do
so, a critical input to enable this technology is wireless spectrums which are typically auctioned off to wireless
carriers by governments. When the first LTE smartphone hit the market in late 2010, it offered clear improvements
over the existing 3G standards (WCDMA & EV-DO) in terms of data throughput and latency by virtue of the new
OFDMA air interface. However, these early designs could only take advantage of one slice (or band) of the
available spectrum at a time just like with its preceding 3G standard. The RFFE for these early 4G LTE devices
were relatively simple and on par in complexity with the existing 3G RFFEs.
It wasn’t until the introduction of LTE category 4 devices did the industry begin on the long path to evolving LTE.
LTE category 4 enabled carrier aggregation (CA) which is the bonding of disparate wireless frequencies into one
larger virtual data pipe so to best utilize the various spectrum holdings of a particular wireless carrier. Along with
the requirement for diversity antennas, the LTE smartphones in 2013/2014 added about twice as much complexity
as the first-generation LTE devices.
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Soon, leading smartphone OEMs started adding more LTE band support to their flagship devices to address the
diversity of LTE frequencies all over the globe and to keep regional SKUs of a particular model to a minimum.
Chart 1 below illustrates the evolution of leading flagship devices over the years along with the growing number of
global LTE band support as well as corresponding levels of LTE category design. In addition, Chart 1 below
illustrates the design evolution of leading iPhone and Android LTE RFFE designs.
Chart 1 – Historical and forecasted LTE RFFE complexity. 4x4 MIMO designs began in 2017 (Apple expected to implement in 2018)
As the years past, LTE Cat-4 gave way to Cat-6 which was capable of aggregating two 20MHz (2x20MHz) blocks
of frequency instead of the two 10MHz (2x10MHz) block of its predecessor. At the same time, smartphone OEMs
continued to add even more global band support which necessitated more filters, switches and power amplifiers in
the RF path as LTE band aggregation combinations grew exponentially. By 2016, the industry began introducing
LTE CAT-9 RFFE designs capable of 3x20Mhz carrier aggregation. These developments in the first six years of
LTE evolve the network capability from 100mbps to 450mbps theoretical throughput limit – more than 4x
performance increase – which also came at the price of increased RFFE complexity (number of radio paths grows
geometrically).
The next step-function in the LTE evolution was the introduction of higher order modulation (256QAM) in Cat-11
and higher devices which pushed the max theoretical throughput of a 3x20MHz system to 600mbps or 33% faster
speeds. Also, 4x4 MIMO antennas layout was implemented shortly afterward to take advantage of additional spatial
layers in the mid and high LTE bands. Again, these advancements added to the overall growing complexity in the
RFFE. To combat this engineering problem, RF component manufacturers modularized Front End (downlink) and
transmit (uplink) chains to include frequency specific components like low-noise filters, duplexers, switches and
power amplifiers. These modular parts are known as FEM or PAMs (Front-End Modules & Power Amplifier
Modules for both downlink and uplink radio chains respectively) which simplified the RFFE design as well as kept
4
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5
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CY2014 CY2015 CY2016 CY2017 CY2018 est. CY2019 est.
Evolving LTE RF FE Complexity
Max # of LTE Bands Supported - iPhone Max # of LTE Bands Supported - Leading Androids
Max LTE Category - iPhone Max LTE Category - Leading Androids
4x4 M
IMO
CA
256 Q
AM
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Ma
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ility
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the PCB footprint inflation in check. Meanwhile, OEMs had to take on the burden of becoming world class RFFE
designers in order to integrate and manage the runaway complexity of their RFFEs.
Chart 2 and Chart 3 illustrate the generational growth in complexity of the RFFE using historical Apple iPhone
models as example:
Chart 2 – Note: *denotes iPhones with Intel LTE modem/RF design (all others contain Qualcomm)
Chart 3 – Apple iPhone designs are split into two form factors for comparison. Jump from 2x carrier aggregation (CA) to 3x CA was most pronounced producing roughly 50% increase in board space. Increasing number of LTE band support and CA combinations adds to overall complexity.
0
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10CAT-4 iPhone 6
CAT-4 iPhone 6 Plus
CAT-4 iPhone SE
CAT-6 iPhone 6s
CAT-6 iPhone 6s Plus
CAT-9 iPhone 7*
CAT-9 iPhone 7 Plus*
CAT-12 iPhone 8*
CAT-12 iPhone 8 Plus
CAT-12 iPhone X
# of FEM/PAM modules
Source: IHS Markit © 2018 IHS Markit
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iPhone6
iPhone6s
iPhone7*
iPhone8*
iPhone6 Plus
iPhone6s Plus
iPhone7 Plus*
iPhone8 Plus
4.7" 4.7" 4.7" 4.7" 5.5"5.5"
5.5"5.5"
CAT-4 CAT-6 CAT-9 CAT-12
CAT-4CAT-6
CAT-9CAT-
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Today, leading smartphone OEMs are releasing LTE Category 16 and 18 capable devices. These are referred to as
“LTE Advanced Pro” since the technology would enable theoretical speeds of 1Gbps or more with up to 5x carrier
aggregation. For leading OEMs, this meant that they had to invest heavily in RFFE design capabilities as the RF
complexity ramps with each model upgrade in the competitive smartphone marketplace. In pursuit of the ever-
evolving LTE radio standard, companies pour in millions of dollars’ worth of Non-Reoccurring Engineering (NREs)
expenses into solving their RFFE design problems. Those OEMs that can afford it, do so for strategic reasons (e.g.
Apple, Samsung and Huawei), while lesser OEMs are challenged to keep pace with RFFE complexity. Also, as the
industry enters the end of the decade and the start of a new “G” with 5G NR, the RFFE complexity will only
continue to grow, making this a more pressing problem for everyone in the market.
Hence, there is a clear need in the industry for a solution to tame this runaway RFFE complexity and the answer for
Tier 2 smartphone OEMs that wishes to remain competitive in today’s marketplace is to essentially outsource the
RFFE design.
Enter Qualcomm/RF360
In January of 2016, Qualcomm and TDK announced a joint venture to develop RFFE components and provide
additional choice and solutions to the industry. Before this announcement, major merchant mobile chipset providers
such as Qualcomm and MediaTek relied on RF componentry from third party firms in their reference designs and
it was up to the design integrator (whether it be an ODM or OEM) to put the pieces together and come up with a
working RF solution for their particular smartphone model. This joint venture was a bold move to vertically
integrate the RFFE portion of the supply chain, which would cover the length of the modem to antenna path. A
year later, Qualcomm purchased the remaining shares TDK owned in the JV and began putting together all the
missing components in the RFFE that did not have a Qualcomm label on it. This was an unprecedented move in
the industry but what Qualcomm had ultimately created was a complete modem-to-antenna system solution to
address the problem of growing RFFE complexity. Qualcomm brought together its existing envelope tracking,
antenna tuner products, power amplifiers in gallium arsenide and CMOS as well as switching technology through
another acquisition to augment those with the assets from the JV, namely BAW, SAW and TC-SAW filters as well
as module capability to create a full RFFE solution.
As LTE RFFE designs gets increasingly more complicated heading into the gigabit LTE age, only the most well-
funded smartphone OEMs can afford to employ an army of RF engineers to develop proprietary RF solutions. This
creates an uneven playing field and a clear need for Tier 2 OEMs to move more quickly and update their smartphone
designs with new innovations in order to maintain competitive. Qualcomm’s RFFE solution answers that need by
allowing these OEMs to focus on market differentiators such as display, form factor and camera innovations,
bringing them to market sooner and leaving Qualcomm to solve all the RF complications of advanced LTE RF.
In the next segment of this whitepaper, IHS Markit will explore the results of this RFFE vertical integration as
implemented in several OEMs designs that have adopted Qualcomm’s complete modem to antenna RFFE solution.
The following physical RFFE analysis of four production smartphones by four different OEMs performed by IHS
Markit Technology teardown team goes into detail on the components that make up the four different RF front ends
and how each of these OEMs takes some parts of or, if not, all of Qualcomm’s RFFE design for the common
Snapdragon 845 mobile platform.
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Teardown Results
(1) Sony Xperia XZ2 Compact
• 5.0", 18:9 Full HD+ HDR [LCD] display
• 19MP camera capable of 4K HDR video
• Image processing engine capable of 960 frames/second recording
• 4GB RAM / 64 GB UFS storage
• LTE Cat-15 RFFE (up to 800mbps)
• IP68 rated enclosure
Sony was the first OEM to announce that it will leverage Qualcomm’s new complete RFFE solution at Mobile
World Congress 2018 for its new Xperia XZ2 flagship line. IHS Markit Technology had obtained the compact
version of the Sony Xperia XZ2, which contained the same Qualcomm Snapdragon 845 platform and RFFE as the
larger flagship model.
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Of interest in this RF design is the near completeness of the Qualcomm RFFE solution. The Sony Xperia XZ2
employs three QDM-series front-end modules as well as three QPM-series Transmit or PA modules. Furthermore,
the Sony design employs two envelope trackers (QET4100) for dual carrier uplink, a relatively rare RFFE design
enhancement to increase the upload speed of smartphones. Further, the inclusion of a Qualcomm QAT3550
impedance tuner rounds out the design as the RF chain terminates at the primary antennas. Impedance tuners are
particularly useful in correcting for signal lost during use, as LTE radio waves attenuates as a result of hand-holding
or just to correct for RF reception problems brought to bear as the antenna design have taken a backseat to the
desired industrial design of the OEM. Sony, in the case of the Xperia XZ2 Compact wanted to achieve an ergonomic
Graphic 1
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design that incorporates a dished contour on the backside of the device to better be used single handedly. This
physical design choice often run contrary to the optimal RF designs and therefore, an addition of the impedance
antenna tuner helps to compensate for that industrial design choice.
(2) LG G7 ThinQ
• 6.1”, 19:5:9 QHD+ Notched [LCD] Display
• Dual 16MP cameras (standard & wide)
• IP68 enclosure
• Quad DAC (audio)
• 4GB RAM/64GB storage
• LTE Cat-16
The LG G7 ThinQ is the successor to the G6 model from 2017 which, at the time, was a LTE Cat-11 device. LG
relied on Qualcomm’s RFFE expertise to help them achieve a gigabit LTE Cat-16 design for the G7 ThinQ, which
represents one of the first 4x4 MIMO antenna designs coming from LG.
Of note on the LG G7 design is the use of Qualcomm RF360’s RF extractor at the GPS antenna. Qualcomm has
won similar design slot wins in Samsung as well as Google’s Pixel design with this RFFE part
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On the bottom side of the main PCB of the LG G7, there is a pair of diversity receive front-end modules provided
by Qualcomm (QDM3670&3671; item 3&4 in Graphic 3). The location of these two FEMs (top side of the device)
suggest they attach to the two diversity antennas that comprise of the overall 4x4 MIMO antenna system. The
primary antenna and transmitter would then be located at the opposite end of the PCB, which corresponds to the
bottom of the device.
Other Qualcomm RFFE components implemented in the LG G7 are QPM2622 PAMiD or PA module with
integrated duplexers as well as a QET4100 envelope tracker to modulate the LTE transmits power more efficiently.
Rounding of the Qualcomm RFFE design is an antenna tuner located at the diversity antenna portion of the PCB.
Graphic 2
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In the case of LG, who is arguably a Tier 2 OEM compared to their fellow Korean competitor Samsung, outsourcing
its LTE CAT-16 RFFE design to Qualcomm made sense as it frees its designers up to focus on other competitive
features which would help the G7 stand out. As a perennial No. 2 to Samsung, LG can innovate at the same pace
as its domestic competitor with fewer staff and not sacrifice on falling behind in the RFFE design and capability.
Graphic 3
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(3) HTC U12+
• 6”, 18:9 Quad HD display
• 6GB RAM/64GB storage
• 12MP + 16MP primary cameras
• Phase and laser autofocus detection
• 8MP+8MP dual front facing cameras
• LTE Cat-18
HTC has long been a Qualcomm design brand. In fact, one of the first LTE smartphones ever produced was the
HTC Thunderbolt featuring the first-generation Qualcomm LTE thin modem (MDM9600). For the CAT-18 design
of its 6-inch flagship device, HTC used a similar RFFE design as the Sony Xperia XZ2 with three QDM front-end
modules and three QPM transmit or power amplifier modules.
Also, like the Sony, the HTC U12+ uses two QET4100 envelope trackers for carrier aggregation on the uplink or
transmit portion of the RF chain. This would, of course, increase the LTE uplink or transmit speed 2 folds by
leveraging two carriers instead of one. Also, the U12+ design uses an antenna tuner part from the Qualcomm RFFE
portfolio.
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Graphic 4
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Graphic 5
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(4) OnePlus 6
• 6.28”, 19:9 2280 x 1080 display (AMOLED)
• 16MP + 20MP primary cameras
• 6GB RAM / 64GB USF Storage
• LTE Cat-16
• 25 global LTE bands support (TDD & FDD)
OnePlus has always been an interesting smartphone OEM brand who is known for its unique designs,sales and
marketing. It is a Chinese OEM who has created a loyal customer following particularly in Europe and North
America markets. OnePlus sells directly to consumers – bypassing the carriers – and thus, have a larger challenge
in its RFFE needs as it needs to address a wider breath of locales and LTE support.
The OnePlus 6 is its latest flagship featuring a large 6.28” AMOLED display. Like many of the flagship devices in
2018, it features a notched display made popular by the iPhone X. This design would allow for the edges of the
display to be pushed nearly to the width and height of the physical phone. A notch is incorporated to make room
for front-facing cameras and sensors. Eventually, this design will be superseded by full-display models with cut-
outs or holes for these components.
For the RF front end, OnePlus leaned on Qualcomm to provide its FEM solutions. The OnePlus 6 includes the
familiar 3 QDM solutions. However, for the transmit or PA modules, OnePlus opted for a Avago solution – likely
to be able to address all of the 25 global LTE bands and CA combinations it supports in the fewest module or PCB
space. The upcoming “red” SKU of the OnePlus 6 is expected to use a complete Qualcomm RFFE solution akin to
the Sony or HTC models described previously.
Rounding out the Qualcomm RFFE design is a single QET4100 envelope tracker and a pair of antenna tuners.
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Graphic 6
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Graphic 7
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Conclusion
In this whitepaper, IHS Markit has highlighted the growing complexities of LTE Advanced RFFE designs and the
go-to-market challenges for Tier 2 smartphone OEMs as they face ever-increasing competitive forces. By
relinquishing the engineering resources otherwise occupied by updating RFFE designs, these OEMs can outsource
this problem area of smartphone design to an upstream supplier such as Qualcomm in order to focus on the
meaningful design innovations that will make them stand out in the smartphone market landscape. Four teardowns
of production smartphones with this Qualcomm solution were discussed, highlighting the first several design wins
for this new integrated modem to antenna solution.
LTE RFFE will continue to get more complex and with 5G on the horizon, the prospect of a LTE + 5G RF front
end would present a more than daunting engineering problem for any capable OEM to handle. As most global 5G
implementations are of a Non-Stand Alone (NSA) variety, 5G wireless carriers will require smartphones that can
operate both LTE and 5G NR simultaneously. While the Sub 6 Gigahertz section of the 5G radio can share some
RF components with the LTE RFFE section (i.e. antennas), the millimeter wave portion of 5G NR will undoubtable
require a new set of RFFE chains to take advantage of the wider bandwidth segment of the 5G NR spectrum to
achieve the multiple gigabits per second data throughput.
Qualcomm has put together a valuable and unique solution for the smartphone components ecosystem with its
RFFE products. By offering a complete modem to antenna designs to the mobile electronics supply chain, many
of the complications of RFFE design has been solved, allowing nimble smartphone OEMs to concentrate on and
develop compelling flagship devices faster. This complete solution also creates a disruption in the RFFE
components market. Existing players in the RFFE – namely Avago (Broadcom), Skyworks and Qorvo – will now
likely look to partner up with modems suppliers to offer similar solutions or improve their component technology.
Ultimately, competition brings choices and drives down prices. This entry by Qualcomm certainly represents the
first salvo in the RFFE marketplace.
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