It's been an eventful few months for Qualcomm – back in December the company had unveiled the first reference designs of the Snapdragon 855 and demonstrated integration with the 5G X50 modem. It’s easy to forget that the X50 modem has had quite of a long time to market, as we had first reported on the chipset way back in October 2016.

One of the bigger draw-backs of the X50 modem was the fact that it was a 5G only modem – meaning it only had support for 5G NR communication standards, and it had to be paired with the modem inside the Snapdragon 855 in order to offer full network compatibility. This resulted in some awkward solutions such as the Moto 5G Mod, which to say doesn’t represent the most elegant implementation from an engineering stand-point.

Today Qualcomm looks to address this major concern with the announcement of the new second-generation X55 modem: A full standalone multi-mode modem solution. The X55 differs from the X50 in that it supports all communication standards, from 2G, 3G, 4G to the newest 5G standards, no longer requiring the chip to work in combination with a Snapdragon SoC modem. The modem’s 4G capability has also been improved, offering UE LTE Category 22 speeds of up to 2.5Gbps via 8xCA at 256QAM.

X55: A true global 5G modem

Source: GSMA

What is actually one of the most important aspects of the new X55 modem is the fact that it’s Qualcomm’s first true global 5G modem. In 5G mmWave, the industry has largely consolidated around three frequency bands: 26, 28 and 39GHz. The 26 and 28GHz are the first pioneer bands that will be implemented by carriers in the next few years. The problem with the first generation X50 modem is that it only supported the 28GHz and 39GHz bands which are predominantly going to be supported in markets such as North America. The addition of the 26GHz band in the new X55 vastly opens up other potential markets in other continents where there’s more plans for deployment with frequency spectrum starting at a lower 24.5GHz.

Another very important change in the X55 modem is the fact that it now supports 5G NR sub-6GHz in FDD mode. Previously, the X50 only supported TDD frequency bands. While again this might be fine in the first iterations and carrier deployments, lower frequency spectrum at and below 800MHz is only available in FDD duplex mode. It’s extremely crucial to be able to support these lower frequency bands as they give the best range and penetration, and as over the next few years carriers will migrate spectrum to 5G NR, supporting FDD bands will give X55 modem devices much longer longevity and future-proofing. It’s to be noted that the X55 also now supports spectrum sharing, meaning 5G and 4G can co-exist on the same frequencies.

The new modem is manufactured on a 7nm process node, although Qualcomm woudn't confirm if this means the existing TSMC 7nm node or Samsung's new 7LPP EUV node.

QTM525 mmWave antenna module: Enabling new X55 bands in a thinner form-factor

Naturally to be able to support the new 26GHz frequency band, Qualcomm had to also update the RF components. Joining the X55 modem is the new QTM525 mmWave antenna module, succeeding last year’s QTM052.

The new module further improves its form-factor by becoming even narrower than the QTM052: Qualcomm promises it will enable sub-8mm thick phone designs. In terms of spectrum capability, the new module maintains the same 2x2 MIMO 800MHz bandwidth as the QTM052, reaching mmWave band speeds of up to 6Gbps. Qualcomm is able to advertise 7Gbps by aggregating with sub-6GHz bands on LTE.

New Envelope Tracking & Antenna Tuning solutions

Revealed today is also the announcement of two new accompanying RF solutions: The new QET6100 envelope tracker and the new QAT3555 antenna impedance tuner.

The QET6100 isn’t the first 5G ET solution (ET is also available on the X50 and competing solutions), however Qualcomm is able to claim it’s the first to support 100MHz upload spectrum, while its predecessor was only able to support 40MHz. As carriers allow for wider frequency bands, this will be a crucial addition that will improve battery life of devices.

The QAT3555 enables better antenna impedance tuning with the multitude of antennas expected to be employed in 5G devices. Antenna impedance tuning is able to avoid reception issues when users hold their device in certain ways- this was popularly referred to as “death grip” several years back.

Overall, the X55 modem is I think a much more future-proof and elegant solution than what we’ve seen presented in the X50. The X50’s band and mode limitations inherently mean it will only garner limited support by some devices in certain markets. The X55 seems to be truly global in its capabilities, and most importantly also offers a full all-in-one solution meaning we could see the modem paired with non-Qualcomm SoCs/CPUs. Qualcomm expects the first commercial devices with the X55 modem to come towards the latter half of 2019.

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  • masimilianzo - Tuesday, February 19, 2019 - link

    Makes sense thanks.
    Notable that QTM525 antennas are 2x2 MIMO, rather than 4x4.
    But double antennas==even more volume occupied.
  • ksec - Tuesday, February 19, 2019 - link

    2x2 Per Unit and single side. The 4x4 you get from LTE are from All side, not applicable on mmWave since you will only have one side receiving the directional mmWave Signal.
  • DanNeely - Tuesday, February 19, 2019 - link

    With 2g and 3g phaseouts in progress or completed over increasing amounts of the globe, I'm wondering how long until we start seeing next generation modems that don't support anything older than LTE.
  • ksec - Tuesday, February 19, 2019 - link

    Unlikely to happen in the next 3 - 4 years. Different Nations have different plan of sunsetting Pre LTE tech, some decide to keep 2G and get rid of 3G. Some decide to keep 3G while getting rid of 2G. Until LTE is truly rolled out Globally, there is going to be some long tails in Pre LTE tech.

    I also think the Die space required to support those are minimal. It might not be worth the hassle to think about dropping them now.
  • PeachNCream - Tuesday, February 19, 2019 - link

    As interesting as it may be to see improved modem designs that offer 5G speeds, I question the value of the additional performance when TELCOs limit data transfer to small quantities, charge high prices for overages, or reduce transfer rates significantly after hitting a cap even with an unlimited plan.
  • ksec - Tuesday, February 19, 2019 - link

    Additional Speed and Additional Capacity, which provide incentive for Telcos to lower their price to compete. That is of course assuming no growth of Data Usage. But generally speaking the faster you upgrade your phone with faster speed and Wireless tech, the faster telcos can upgrade their infrastructure. It is one reason why Telcos has a Love and Hate relationship with Apple.
  • PeachNCream - Tuesday, February 19, 2019 - link

    Data plans are not keeping up with bandwidth increases despite the incentives of higher speed modems. There are still lots of phone plans that are capped at single digit GBs per month out there and various plans that are represented as unlimited are bandwidth capped after a relatively small amount of information is dragged downstream. Those numbers have increased a little, they're nowhere close to catching up with successive modem advancements.
  • ksec - Wednesday, February 20, 2019 - link

    That is because there are more user. Generally speaking every Telecos in every nations, within their Spectrum and Infrastructure has their optimal capacity. As strange as it might seem there are still many using 3G, moving up to 4G casques additional strain on the network, which then requires refarming. Once the majority of the Data are living on LTE, and reaches a plateau of users, the advancement of Smartphone tech will improve the economics of Carrier. The problem is Smartphone Replacement are now in 4 years cycle, which means unless the Market can Sell enough 5G ( That is why they are hyping it ), the improvement for Telecos, whether it is capacity, speed, business will be slow.
  • ksec - Tuesday, February 19, 2019 - link

    Meanwhile Intel doesn't even have a Spec page for Intel XMM 8160. I just wish Apple gave me a choice, I would pay $50 more for a Qualcomm iPhone.
  • peevee - Tuesday, February 19, 2019 - link

    What is the point, beyond marketing, of 24-40 GHz for mobile phones? They don't penetrate anything. Would they work even in fog or rain? At 10mm wavelength, 20cm of tissue (which is mostly water) is enough to reduce signal strength by the factor of ~1000 AFAIR.

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