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

Confidential. © 2018 IHS Markit. All rights reserved. 2 July 23, 2018

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.



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

6

8

10

12

14

16

18

20

5

10

15

20

25

30

35

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

Source: IHS Markit © 2018 IHS Markit

Ma

x#

of L

TE

Ba

nd

s S

up

po

rte

d

Ma

x L

TE

Cate

ory

Cap

ab

ility



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

2

4

6

8

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


250

300

350

400

450

500

550

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-

12Source: IHS Markit © 2018 IHS Markit



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.



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.



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




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



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




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




(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.



Graphic 4




Graphic 5




(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.



Graphic 6




Graphic 7




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.

Disclaimer

The information contained in this report is confidential. Any unauthorized use, disclosure, reproduction, or dissemination, in full or in part, in any media or by any means, without the prior written permission of IHS Markit Ltd. or any of its affiliates ("IHS Markit") is strictly prohibited. IHS Markit owns all IHS Markit logos and trade names contained in this report that are subject to license. Opinions, statements, estimates, and projections in this report (including other media) are solely those of the individual author(s) at the time of writing and do not necessarily reflect the opinions of IHS Markit. Neither IHS Markit nor the author(s) has any obligation to update this report in the event that any content, opinion, statement, estimate, or projection (collectively, "information") changes or subsequently becomes inaccurate. IHS Markit makes no warranty, expressed or implied, as to the accuracy, completeness, or timeliness of any information in this report, and shall not in any way be liable to any recipient for any inaccuracies or omissions. Without limiting the foregoing, IHS Markit shall have no liability whatsoever to any recipient, whether in contract, in tort (including negligence), under warranty, under statute or otherwise, in respect of any loss or damage suffered by any recipient as a result of or in connection with any information provided, or any course of action determined, by it or any third party, whether or not based on any information provided. The inclusion of a link to an external website by IHS Markit should not be understood to be an endorsement of that website or the site's owners (or their products/services). IHS Markit is not responsible for either the content or output of external websites. Copyright © 2018, IHS MarkitTM. All rights reserved and all intellectual property rights are retained by IHS Markit.

IHS Markit Customer Care:

[email protected]

Americas: +1 800 IHS CARE (+1 800 447 2273)

Europe, Middle East, and Africa: +44 (0) 1344 328 300

Asia and the Pacific Rim: +604 291 3600

Taking the Complexity out of LTE Radio Front End Designs · 2018. 7. 23. · Taking the Complexity...

Documents

Transcript of Taking the Complexity out of LTE Radio Front End Designs · 2018. 7. 23. · Taking the Complexity...