The high level specs on the new 7nm X55 modem include second generation 5G with throughput up to 7/3Gbps down/up on mmWave and 2.5Gbps/316Mbps down/up using LTE Cat22. Impressive as it may sound the details are more important like spectrum sharing, available modes, RF front end, and antennas. Lets dive in to the details and look at what this beast is offering.
X55 and the QTM525 mmWave antenna
The big bang is obviously the mmWave support for up to 7Gbps which is a very impressive number crunching feat in and of itself. There are a lot of devices that don’t have this much main memory bandwidth much less multi-gigabit I/O that needs some very extensive DSP work to process the signal into bits. Don’t underestimate how much calculation is needed here and how efficiently you need to do it in a mobile form factor. If you want a good yardstick to gauge it by, take a look at the heatsinks on 10GbE NICs which have a much easier job of signal processing.
Most of this is made possible by the QTM525 antenna module pictured above, an all-in-one mmWave device. This one now supports the big three mmWave bands, 26, 28, and 39GHz, more than enough to justify the ‘global’ tag Qualcomm uses. Better yet this module is tiny, more than small enough to fit into the bezel of an 8mm ‘thick’ phone. This is where we usually rant about phones getting too thin and should be thicker but we aren’t going to complain about components getting smaller.
One of the most important bits about the X55 is that it supports FD-MIMO or Full-Dimension MIMO. This is the engineering way of saying that on LTE bands, presumably sub-6 5G too since the X55 supports full 4G/5G spectrum sharing, the modem can do MIMO in vertical as well as horizontal dimensions. If you recall MU-MIMO was only horizontal so if your device and infrastructure supports FD-MIMO you should be able to cram a lot of devices into a small area. With spectrum sharing, another critically important technology, LTE and 5G devices won’t have to fight for spectrum use and allocation headaches. Without spectrum sharing, sub-6 5G rollouts would be crippled.
All of this is kind of pointless if you don’t have a good RFFE (RF Front End) and Qualcomm addresses that with the QET6100 Envelope Tracker and the QAT3555 Antenna Tuner. The QET6100 is said to be the first envelope tracker that can do 100Mhz UL bands and it supports 256-QAM and UL-MIMO. For those who remember the iPhone antennagate issues the QAT3555 is the device for you, it keeps the hand-related antenna issues to a minimum. More importantly it allows the antenna to use the minimum power needed to get the job done so you get better signal quality while using less battery. RFFEs might not be headline grabbing but they are critically important to real world use and for some reason Qualcomm is the only one talking about such technology. Pay attention to this area for 5G rollouts, it matters.
In the end we have the fastest, most advanced LTE/4G modem announced to date in the X55. It ups the speeds to 2.5Gbps with Cat22 capabilities and pushes MIMO to another dimension. Coupled with a full RFFE it will share spectrum for 4G and 5G on the sub-6 bands too, plus bezel fitting antenna modules mean the air side is covered pretty well. In short it does it all, then adds second gen 5G capabilities. This allows the Qualcomm X55 modem to push 7Gbps downlink speeds on mmWave frequencies while supporting, well, just about everything 2G-5G. What more could you want?S|A