"Overview:
Early 5g smartphone designs mostly used Qualcomm modem and radio frequency front end (RFFE) components.
Qualcomm currently provides the industry's only commercial millimeter wave 5g modem to antenna design for smartphones.
The cost of 5g RFFE components accounts for a large part of the whole RFFE, and the RFFE driven by mmwave has the most significant growth.
Using mature commercial modems and RFFE solutions, original equipment manufacturers (OEMs) focus their development efforts on the overall design of mobile phones.
With its first mover advantage, Qualcomm is expected to occupy a greater share of semiconductor spending on 5g smartphones.
At present, IHS Markit has sampled 6 OEM manufacturers with 5g smart phones, of which 5 manufacturers have adopted the same solution in the RFFE part - the complete 5g RFFE solution provided by Qualcomm. This not only reflects Qualcomm's important position as a major modem supplier, but also shows that Qualcomm is becoming more professional in bringing industry-leading modem to antenna solutions to the market. Qualcomm has defeated existing RFFE component suppliers and subverted the RFFE market in 5g.
Unlike the previous transition to 4G, when smartphones lag behind network deployment, 5g smartphones can be used on the first day of 5g network release. Moreover, smart phones are the main equipment to display 5g functions. IHS Markit sampled seven unique 5g smartphones from six OEMs. The diversity of OEM brands in early 5g equipment is unprecedented, which poses a challenge for RF technology. In the past, only OEMs with stronger technical capabilities took the lead in launching a new generation of wireless mobile phones. However, in today's 5g era, we also see those new or smaller OEMs, such as Xiaomi, oppo and oneplus - most of them were not famous during the 4G transformation 10 years ago.
Adapt to 5g new spectrum
Early 5g networks were "non independent", which meant that 5g wireless connections needed an anchored LTE signal. For the design of RFFE, LTE and 5g will have two different RF paths. Since the functions of LTE-A (such as carrier aggregation and multi band support) have made the design of RFFE very complex, this demand will pose a greater challenge to the current smart phone RFFE design. In this article, we will analyze the disassembly results of five smartphones and compare their similarities and unique designs.
The realization of 5g spectrum in the new network is of great significance to the design of RFFE. By expanding the spectrum range, 5g will provide greater capacity and higher speed. However, in order to support these wider bandwidths, the RFFE must be redesigned accordingly to support the frequencies used. The sub-6ghz 5g frequency is not challenging because it is similar to the existing LTE RFFE signal.
This 5g band (FR1) is commonly referred to as "sub-6ghz". The transmission characteristics of FR1 signal are the same as the existing high-frequency LTE, but the carrier bandwidth is much wider (100-200mhz, 5-20mhz in LTE).
Another more challenging spectral range (FR2) is millimeter wave 5g. FR2 spectrum has not been widely used in mobile phone applications because of its limited signal propagation and high attenuation. Its maximum open spectrum range is between 24GHz and 90GHz. In order to overcome the traditional limitations of mmwave, special technologies in radio technology need to be adopted to expand the available coverage of FR2. RF technologies such as focused beamforming and beam tracking are deployed at the edge of 5g network to provide hundreds of MHz bandwidth for mobile users.
Analysis of disassembly results
In February this year, many manufacturers released 5g smart phones at the world mobile communication conference (MWC) in Barcelona, and LG was one of them. V50 ThinQ 5g is a sub-6ghz 5g smartphone. It was originally designed for sprint, an American operator, and later used by other global operators deploying sub-6ghz (usually 3.5GHz in n77 / 78 band).
LG adopts Qualcomm's first generation X50 5g design, including a separate 5g transceiver (sdr8154) and a pair of RFFE modules. Qpm5650 transmission module and qdm5650 diversity receiving module support single band n77 / 78 sub-6ghz 5g network. We will see in the subsequent disassembly results that the first generation design has been used in the same RF configuration by three other OEMs.
In addition to RFFE, another design challenge of the first generation 5g smartphone is to find enough PCB surfaces to install additional 5g components. The Qualcomm X50 modem is located at the top of the PCB, adjacent to the snapdragon 855 SOC, and the rest of the RFFE components are installed at the bottom of the PCB. LG chooses to install all 5g components on one main PCB instead of adopting modular (i.e. stacked PCB) design. This design can be replaced with LTE only or 5g version. Therefore, LG V50 thinq is essentially a dedicated 5g smartphone designed according to Qualcomm architecture.
Oppo Reno 5g is the 5g version of its flagship product Reno (LTE only). In order to adapt to the new camera features, Reno has a larger rack, which can use a larger full screen display and a larger built-in battery. This physical design creates additional space to put 5g components into the phone. This strategy allows oppo to sell two different versions of flagship smartphones based on the same design. Of course, the common platform design helps to achieve large-scale production and component procurement. This is a popular strategy in OEM plants seeking to reduce the complexity of the supply chain.
In oppo Reno 5g, the modular radio frequency (RF) board is used to exchange RF components according to different global regions and markets. This approach allows oppo to reduce over investment in unnecessary RF components. Similarly, Qualcomm X50 modem, sdr8154 transceiver and a pair of RFFE modules (qdm5650 and qpm5650) are used to complete the scheme design of 5g modem to antenna. Oppo Reno 5g supports a single common frequency (N78) used in most early European 5g network deployments.
Xiaomi mix3 5g is another application designed by Qualcomm sub6 GHz RFFE. Like oppo Reno discussed earlier, the MI mix3 5g is designed to be highly configurable to serve different global markets. Xiaomi has created a 5g version using the existing Mi mix 3 design platform. Xiaomi's adoption of this design method will not only help to obtain the 5g market faster, but also help to manage the overall equipment SKU.
In line with the spirit of OEM manufacturers, Xiaomi mi mix3 5g is the price leader of this mobile phone, starting at 600 euros (about 680 US dollars).
Xiaomi adopts a fully modular 5g design from modem to antenna (while oppo adopts a modular RFFE design), which is a smart choice for 5g function to quickly enter the market. The above 5g PCB components include a complete X50 modem, sdr8154 transceiver, qpm5650 front end and qdm5650 diversity module. There are also unfilled chip landing platforms in the MI mix3 5g board. This is due to the design consideration of the market with two different sub-6ghz 5g frequencies in China. The model sampled here is designed for the European market, which mainly uses n77 / 78 band.
OnePlus 7 Pro 5g is the same as LG V50 5g design. All 5g components of Qualcomm are installed on a common main circuit board. However, unlike LG V50, oneplus 7pro is not specifically built for 5g smartphone platform. Instead, they use their oneplus 7 Pro platform to add 5g functions - using the same strategy as oppo and Xiaomi. By reusing existing designs, oneplus can keep most LTE only designs independent (reduce costs). However, in order to adapt to 5g components, oneplus chose a new PCB design instead of the modular route introduced by oppo and Xiaomi.
In order to create the necessary space to accommodate the front camera, the shape of the oneplus main circuit board is very strange. The selfie camera pops up when needed and retracts into the phone when not needed. For oneplus, the only compromise in 5g design is to create a completely different main PCB design between LTE only and 5g versions. Although this strategy increases the manufacturing complexity, considering the space required for the pop-up self timer camera, it can reduce the thickness of the mobile phone as much as possible. Oneplus 7 Pro is a 5g smartphone exclusively launched on the UK EE network and can run on the 5g band N78.
Samsung Galaxy S10+ 5g is one of the few mmwave 5g devices on the market. Unlike oppo, Xiaomi or oneplus, Samsung is developed on a larger version of Galaxy S10 series flagship phones. Therefore, compared with other Chinese OEM manufacturers, this smartphone platform designed for 5g is more similar to LG V50 5g. There are two different versions of Samsung Galaxy S10 + 5g. One is used for sub-6ghz 5g (international market) and the other is used for mmwave 5g network exclusively owned by Verizon in the United States. The model we will discuss is the mmwave version.
For the mmwave version, Samsung chose to use Qualcomm X50 modem solution instead of their own exynos platform. Different from the previous four sub-6ghz 5g phones, this galaxy model has three mmwave antenna modules (qtm052) located on the back of the phone. Due to the high attenuation characteristics of mmwave, the design of RFFE must be re conceived. The solution provided by Qualcomm is to use a highly integrated transceiver to antenna module design. Because mmwave can be blocked by simple actions, multiple antenna modules need to be deployed so that there is always an exposed mmwave antenna module during normal use.
The use of mmwave may be the most difficult technical challenge in 5g industry. U.S. operators such as at & T, T-Mobile and Verizon decided to take the lead in launching mmwave 5g. The benefits of mmwave 5g are obvious, but it brings extremely difficult engineering problems to the RF design, and finally increases the overall design cost.
Samsung's use of Qualcomm's mmwave solution fully demonstrates the maturity of Qualcomm's modem to antenna solution. It is unusual for a capable large OEM like Samsung to outsource RFFE design, but as far as mmwave is concerned, only Qualcomm has a proven design. Among the existing participants in the RFFE market, only skyworks has the mmwave solution, but it is not mature enough to be commercialized.
The following figure shows the complexity of Samsung Galaxy S10 + 5g design. In the main PCB, there are two unfilled landing platforms, because in the later version of Galaxy S10 + 5g, the smartphone is designed with mmwave and sub-6ghz RFFE at the same time. The larger board supports sdr8154 5g transceiver, and the smaller board supports 5g pamid for n41 band (qpm5580).
Samsung engineers created three internal "cavities" for Qualcomm's three qtm052 mmwave antenna modules, which will be installed directly under the back cover to obtain the best RF reception effect.
Millimeter wave antenna modules need to be highly integrated to reduce the distance (and signal loss) between RF components. The module includes a series of four phased array antennas, which are encapsulated with power management IC (PMIC) and transceiver under antenna stack. In mmwave communication mechanism, the signal budget of 5g RFFE is very important. Choosing Qualcomm's solutions instead of its own RF solutions proves Qualcomm's early technology leadership in mmwave 5g technology. Having a complete modem to antenna solution is also crucial to ensure optimized signal reception and low power consumption of 5g radio.
The demand for redundant mmwave antenna modules will significantly increase the BOM cost of mmwave 5g mobile phones. In the future, with the expansion of the supply chain of mmwave 5g antenna module, the price of antenna module and other 5g RF components will decrease. However, there is no doubt that the first generation 5g RFFE will cost more than the existing LTE RFFE solutions. Therefore, in the first generation example, the cost of mmwave components far exceeds that of multi band LTE RFFE.
First generation 5g RF front end cost premium
The figure above summarizes the cost premium of 5g RFFE added to the five first generation 5g mobile phones mentioned in this article. The cost of 5g baseband is not included in BOM cost analysis. The cost comparison between LTE and 5g RFFE is limited to RF transceiver to antenna components.
According to the disassembly data, the cost premium of 5g RFFE at sub-6ghz is about half of the cost of existing LTE RFFE. The cost of millimeter wave scheme (taking Samsung equipment as an example) is twice that of existing LTE RFFE, which is surprising. It can be seen that the cost of early 5g equipment is high. Just like the LTE design just came out ten years ago, the subsequent 5g mobile phone design should reduce the cost of 5g RFFE. In the mature 5g design, 5g RFFE is expected to be integrated into the design of 5g / 4G / 3G RFFE. This cost premium chart emphasizes the importance of 5g RFFE. From the perspective of component cost, 5g RFFE is as important as modern chipsets.
The importance of modem to antenna (Modem-to-Antenna) design in 5G
As mentioned above, the 5g era has brought new challenges to core electronic suppliers. Specifically, the performance of modem is no longer the standard to measure performance, and the whole modem to antenna design is considered to be a new standard for 5g component products. Qualcomm obviously grasped the first mover advantage of this new design paradigm, that is, to provide a complete 5g RFFE product, but the existing RFFE suppliers did not sit idly by and watch the market dominate. With the maturity of 5g smart phones, the RFFE component market is expected to heat up, and the existing parts manufacturers will respond and provide more complete RFFE solutions. For Smartphone manufacturing,
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