One of the aspects of the transition to 4G to 5G that we probably should talk about a little more is Dynamic Spectrum Sharing (or DSS for short). Two reasons for that: The first is that Dynamic Spectrum sharing is going to play a crucial part in accelerating 5G deployments around the world. The second is that it’s such a brilliant feat of engineering that it deserves its own share of attention. First things first though: what is Dynamic Spectrum Sharing?
Spectrum, radio frequencies, and turnip fields
The first step to answering that question is to define what “spectrum” means, and the simplest way to do that is to think of mobile phones as radios: We all know that radios can access different frequencies. All one has to do is switch from one channel to another by turning the dial or switching from one preset to another. Phones work much in the same way when talking to a cell tower. In practice, it’s a little more complicated than that, but the principle is the same: Whenever you make a call, or send an email, or download a video with your phone, it is accessing some part of the spectrum.
The second step to answering that question is to note that as we transitioned from 2G to 3G to 4G – and now to 5G,- mobile carriers started adding more and more spectrum to the mobile ecosystem. And as they did, cell phones had to be able to access all of these bands. The challenge, however, was that whenever a new “G” was released, it could take years for that new technology to be applied retroactively to older “legacy” spectrum bands. This was because operators had to wait until enough mobile users had migrated out of the older bands to reconfigure them for use with the new G. For instance, when 4G was first released, it could initially only be applied to the new spectrum opened up for 4G. Deploying 4G to older legacy bands used by 3G phones had to wait until enough mobile users had transitioned to 4G phones and effectively “cleared out” of the 3G bands. That process is called re-farming, presumably because it echoes field management in agriculture: Say you have a turnip field that you need to turn into a pepper field. You can’t just start planting peppers in the middle of your turnips. You have to pick your turnips first, then clear and repurpose your field, and only then can you turn it into a pepper field.
Dynamic Spectrum Sharing to the rescue
And here is where Dynamic Spectrum Sharing comes in: It allows a cell tower to segregate slivers of spectrum already being used by 4G users in a specific location, and let a 5G phone user access 5G using that band. In our farming analogy, Dynamic Spectrum Sharing allows you to plant your peppers in the gaps between your turnips, and thus maximize every inch of your field. For mobile operators, mobile users, and mobile chipmakers, this is obviously a game-changer, as it removes a hurdle that had, for the last two decades considerably slowed down the pace of adoption during transitions between 2G to 3G, then 3G to 4G. Dynamic Spectrum Sharing will allow 4G and 5G phones to operate simultaneously in virtually all frequencies used for 4G today.
New modems and antenna solutions for smooth multimode performance
Qualcomm’s Snapdragon X55 5G modem was designed with this capability in mind, and can be paired with 5G mmWave antenna modules, RF transceivers for 5G sub-6 GHz and LTE, and sub-6 GHz RF front-end modules, to access all major spectrum bands.
Dynamic Spectrum Sharing is another way that 5G proves to be a radical step beyond 4G, and it highlights the degree to which the discussions we have about 5G need to start moving beyond gigabits per second speed tests. We aren’t just talking about download speeds here. We are talking about system intelligence. Only this innovation didn’t sprout just from inside the networks themselves. Advancements also came from the device side, and it was fine-tuned by 5G leaders, chief among them Qualcomm and Ericsson.
2020: the year Dynamic Spectrum Sharing rubber really meets road
Now… it’s only 2019, and global 5G deployments only just began a few months ago, but thanks to Dynamic Spectrum Sharing and solutions like the snapdragon X55 finding their way into 5G phones next year, transitioning from 4G to 5G will occur much faster and more smoothly than the transition from 3G to 4G.
To be continued.
Next time, we will focus on the importance of dynamic spectrum sharing to the IIoT. There is a lot more to talk about.