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TriQuint highlights LTE challenges and business opportunities
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Monday 13 January 2014

Mobile devices changed our life enormously. Mobile technology is essential for our lifestyle. A few years ago, a mobile phone was just a device used to make phone calls. However, time has gone by, nowadays most of us have a smartphone or tablet and use it just more like a computer. Today, those smart devices are equipped with GPS, accelerometer, cameras, proximity sensors, NFC technology, gyroscope....

We cannot live without them. It's said that the 95% of us stay no more than 1 meter away from our cell phones. This means that we can answer calls, read messages, check mail anytime, anywhere. This phenomenon is driving a rapid increase in data traffic. It's expected to grow more than ten-fold over the next five years as smartphone adoption continues. This explosive increase is being driven by the seemingly insatiable consumer appetite for mobile broadband services to support Internet access, video streaming, content downloading, gaming and other high-bandwidth, data-intensive multimedia applications. The surging demand is straining the communications infrastructure. As a result, service providers around the world are upgrading their networks to ensure they have sufficient capacity and coverage to meet customer expectations.

TriQuint, a leading provider of innovative RF solutions and foundry services, offers high-performance solutions for advanced approaches, leveraging strong integration expertise to pack more functionality into single modules that are considerably smaller than discrete solutions.

The following is the interview during which TriQuint discussed the company's view and business opportunities in the mobile device and network infrastructure sectors, and the outlook for the industry.

LTE Deployments Accelerate

Q1: How is LTE technology affecting the wireless network infrastructure?

A: LTE deployments give service providers more efficient ways to carry significantly more data traffic, driving much higher capacity requirements from the base station to the points across wireless networks; this capacity crunch also affects optical fiber networks used to backhaul data and connect mobile subscribers to internet hubs and international destinations. LTE enables better usage of available spectrum, faster data rates, reduced latency, lower per-gigabyte transport costs and simpler network architecture. In Figure 1, the statistics highlight LTE device growth of more than 3 times over the next four years.

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Fig 1: Projections of strong growth for LTE smartphones

With more LTE devices arriving, it will boost infrastructure investments significantly. Operators worldwide have launched more than 200 LTE networks so far, with many more planned. The ramp to 4G is happening much faster than conversion to 3G services. In Asia Pacific, for example, LTE networks are expected to cover more than half of the population by 2018.

Meanwhile, mobile carriers are easing the strain on their overstretched networks by offloading an increasing amount of data traffic onto Wi-Fi and small cell networks, such as micro-, pico- and femtocells. Small cell base stations will play a key role in heterogeneous networks (HetNets) as systems expand coverage in densely-populated urban areas. HetNets allow operators to optimize their spectrum portfolios and existing radio network assets, while delivering a better overall customer experience. The advent of small cells also has the potential to transform network economics by delivering service to rural areas, where their lower costs make deployment profitable even for low population densities.

As wireless networks evolve to 4G and beyond, the bandwidth needed to each cell tower increases dramatically, so another challenge operators face is backhauling data from these miniature base stations. Optical networks are a logical solution, along with microwave radios. Optical networks provide higher capacity, better quality and reduced costs for new applications. The microwave / point-to-point radio alternative sees the greatest number of systems from 9 to 27 GHz, offering substantial bandwidth and range. While optical fiber can be readily upgraded from 10 to 40 to 100 Gb/s and beyond, microwave radio can reach areas where fiber deployment is too expensive or slow. TriQuint offers high-performance solutions for all these approaches, leveraging our integration expertise to pack more functionality into single modules that are considerably smaller than discrete solutions.

Q2: How are LTE deployments impacting the smartphone market?

A: The LTE build-out is escalating band counts within smartphones dramatically, creating new challenges for design engineers. Along with meeting more stringent performance requirements, designers must accommodate a rapidly increasing number of frequency bands within each mobile device. Next-gen smartphones must continue to support the primary 2G bands, 3G bands and new 4G, plus Wi-Fi and Bluetooth. The five dedicated bands for 3G pale in comparison to the more than 20 4G LTE bands, and this number could rise to more than 40 in the future.

Q3: What about the shift to high-performance filters as LTE continues to be deployed? How will that affect the market?

A: Filters play a critical role in the RF front-end, because they selectively pass desired signals while rejecting unwanted noise. Unlike PAs, which can cover multiple bands, filters are band-specific, so growth in band counts leads directly to the growth in the number of filters or duplexers within each device. Though it's not practical to support all worldwide bands in a single smartphone, a feature-rich model for international use might need to filter transmit and receive paths for 2G, 3G and 4G in up to 15 bands, as well as Wi-Fi, Bluetooth and GPS. Such a phone might require as many as 30 to 40 filters. The situation is likely to become even more complex in the future: next-generation high-end smartphones could include 50 or more filters. Adding to the filtering requirements, smartphones need multiple filters for each FDD-LTE and TDD-LTE band - as many as three filters: a duplexer for the primary TX path, one for the RX path plus an additional filter for the secondary RX path. Depending on the band, a Wi-Fi coexistence filter is often needed, too.

Q4: What kind of filter technology will be required to meet LTE performance specifications?

A: As the number of required filters grows, so too do the performance requirements. Not only must all these bands within each device be isolated to avoid interference, but spectral crowding means that guard bands between adjacent bands are being reduced significantly or even eliminated entirely. High-performance filters are needed for mitigating the resulting interference issues. In some regions, bands are being re-farmed for LTE, which may also change the filtering requirements; narrow 5 MHz and 10 MHz 4G LTE bands require filters with sharper corners than 3G WCDMA, for example.

TriQuint leverages its advanced technology portfolio, to solve the toughest filtering challenges. While our surface acoustic wave (SAW) and temperature-compensated SAW (TC-SAW) filters are well suited for up to about 1.5 GHz, TriQuint's bulk acoustic wave (BAW) filters deliver compelling performance advantages above this frequency.

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Figure 2: The overview of different LTE frequency by regions and filters.

Our BAW technology offers the only way to meet requirements for some of the most challenging LTE bands. BAW filters deliver exceptionally precise performance including steep skirts and high rejection along with very little temperature drift - ideal for addressing the most vexing interference rejection problems between adjacent bands. BAW filter size also decreases with higher frequencies, which makes them ideal for the most demanding 3G and 4G applications where performance and size are crucial.

Impact of Regional Band Allocations

Q5: What's the impact of regional differences in band allocations on phone design?

A: Phone designers must grapple with significant differences in band allocations among regions and even between countries. The situation will become even more challenging as more LTE bands are allocated in the future. In Asia, for example, the LTE picture is a complex map of regional band assignments with several distinct local markets. China is a huge potential market with unique requirements; other countries also have distinct needs, notably Japan and Korea, which, like the U.S., are the two nations that are most rapidly moving to LTE.


In China, the predominant LTE technology is LTE-TDD, as opposed to the LTE-FDD primarily used in North America. Many of the LTE bands are at higher frequencies, including several that are adjacent to the Wi-Fi band. This situation creates a strong requirement for BAW Wi-Fi coexistence filters. For example, two of the LTE-TDD bands allocated are Bands 40 and 41, as shown in Figure 3.

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Fig 3: China Bands 40 and 41 LTE-TDD bands are adjacent to the Wi-Fi band

The Wi-Fi frequencies are sandwiched between these two bands. There is absolutely no gap between Band 40 and the lower end of the Wi-Fi band, and only a minimal gap between Band 41 and the upper end of the Wi-Fi band.

High-performance BAW coexistence filters will be needed; in addition, tradeoffs may be necessary depending on customer priorities. Supporting the full width of Band 40 may require giving up some of the lower Wi-Fi channels. Alternatively, manufacturers may choose to give up part of Band 40 if supporting the full Wi-Fi bandwidth is their top priority. The coexistence situation with Band 41 is slightly less challenging because of the minimal guard band between Band 41 and the Wi-Fi spectrum.
Within China, there is some local variation; for example Bands 7 and 38 replace Band 41 in Hong Kong.


Korea is particularly interesting because of its high smartphone use and rapid LTE adoption. About 26 million people-more than half the population--already have smartphones, and about 15 million of those are expected to be using LTE by the end of 2013. Korea is re-farming Bands 3 and 5 for LTE, and starting this year, every phone is expected to support Band 7. Band 26 has also been allocated and will require TC-SAW; though it overlaps with Band 5, Band 26 includes some frequencies that a Band 5 filter cannot cover. Bands 3 and 7 will require BAW filters; there is also a substantial need for Wi-Fi coexistence filters.


The situation in Japan further adds to the regional complexity. Japan is unusual in its use of Bands 26, 11 and 21; Band 41 is also used, requiring a BAW Wi-Fi coexistence filter.

Q6: What about issues concerning carrier aggregation?

A: As capacity demands on mobile wireless networks increase at an explosive rate, the scarcity of radio frequency allocations has made spectrum one of the most valuable and rapidly appreciating commodities in modern history. That's what makes carrier aggregation, as enabled by LTE-Advanced capability, so attractive. It enables network operators to consolidate multiple fragmented slivers of spectrum into a single wider channel to enable higher data rates and increase capacity. LTE-Advanced will require high-performance filter technology, and TriQuint is collaborating closely with operators, chipset providers and other ecosystem partners to solve the toughest RF challenges. See Figure 4.

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Fig 4: Carrier aggregation enabled by LTE-Advanced capability

Trend to Integration Continues

Q7: With the market pushing toward integration, what are the unique qualities of TriQuint that can deliver continued success in such an environment?

A: RF solutions are continuing to move to higher levels of integration. TriQuint is taking on this design challenge to simplify RF design and optimize performance by providing more capability in less space for our customers. We've made significant advancements in miniaturization, power efficiency and system performance. We're leveraging active and passive process technologies to integrate the growing number of puzzle pieces into a few tiny modules - while conserving precious battery life.

TriQuint is seeing high demand for multi-band, multi-mode power amplifier modules (MMPA) so OEMs can support numerous cellular bands in less space. For example, our first MMPA combined a quad-band EDGE amplifier with two data bands. The second generation offered four data bands, and our third-generation will house as many as 10. These highly integrated modules in an ultra-small form factor shrink overall product footprints while reducing external component count, minimizing assembly costs, speeding time-to-market, and enabling industry leading performance. In addition, device manufacturers use this common RF footprint to limit the proliferation of regional phones and speed design time.

TriQuint's ability to integrate our premium filters with our active components such as power amplifiers and switches into single, densely-packed modules that package more functionality into smaller footprints is a distinct competitive advantage. Our multi-band power amplifier-duplexer modules are a great example of this innovation. TriQuint's packaging technologies include our CuFlip flip-chip, which uses copper 'bumps' to replace wire bonds, along with wafer level packaging. Both integration techniques enable smaller RF solutions with reduced height for today's thin and light mobile devices.

Q8: What is your product strategy in this area to ensure that you will have a unique product lineup moving forward?

A: TriQuint is ideally positioned to capitalize on industry trends. We're laser-focused on developing differentiated products that deliver value and provide industry-leading performance in the world's smallest form factors. TriQuint's differentiated filter technology gives us a distinct competitive advantage for solving our customers' toughest interference challenges. TriQuint is uniquely positioned to provide high-performance BAW and TC-SAW filters in volume. In addition, with our strong RF integration capabilities we can combine our sought-after premium filters into integrated modules that pack more capabilities into smaller footprints.

Q9: What's the strategy for the emerging LTE business opportunities in APAC market?

A: The upcoming deployment of LTE in Asia will continue to have a significant impact. The number of subscribers who will switch to 4G over the next five years is staggering. Besides providing LTE products for mobile devices, TriQuint supplies RF solutions for the base station market. Our product revenue from the base station market is up primarily because of early support for China's upcoming TD-LTE build-out. More than 200,000 LTE base stations are currently being deployed.

The rollouts of LTE and LTE-Advanced will spur demand for TriQuint's integrated, high-performance RF solutions, so we're making investments in capacity to keep pace. R&D continues to be a priority as we develop unique technology and packaging techniques to deliver RF solutions that improve performance and reduce size, thereby furthering our commitment to innovation by delivering real customer value.

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