The US mobile market is undergoing a ton of change. Just over the past few months we saw Verizon follow T-Mobile’s lead and do away with contracts. All four major carriers now unbundle device payments from service payments. Device manufacturers, like Apple and Samsung, started to roll out their own device financing plans. And data usage continued to skyrocket around the world (pdf), thanks to further deployment of faster network infrastructure.

This progress is great for us. No more contracts and price transparency simplify the process of comparing service providers, and faster data via LTE is obviously awesome.

But now that service and device pricing is simpler, choosing the right device should be simpler too right?

This week Questions to Carriers will take a deeper look into LTE bands and the complications they can create for us when choosing a device.

As we learned in last week’s Questions to Carriers, LTE is currently the fastest widely-deployed mobile data network infrastructure. It’s a single standard that all four major US carriers adopted along with the vast majority of carriers around world. Currently LTE is deployed in 118 different countries on 335 different networks (pdf). This global deployment of LTE means devices shouldn’t be tied to specific and incompatible network infrastructures anymore.

Remember that in the US, AT&T and T-Mobile built out GSM networks, while Sprint and Verizon opted to build on CDMA. This lead to different versions of popular devices specific to each network infrastructure. A device purchased to work with AT&T’s GSM network wouldn’t work on Verizon’s CDMA network and vice versa. Now that all carriers have adopted the single LTE standard, in theory it’s practical to develop a single device that will work on all carriers.

You may have seen Apple’s new iPhone 6s advertised as “carrier-unlocked” and “carrier-free”. These terms refer to two different forms of carrier independence. “Carrier-unlocked” means there isn’t a flag set deep in the system software that prevents the iPhone from connecting to multiple carrier networks. “Carrier-free” means the iPhone has all of the low-level hardware and software required to connect to any carrier’s network. The hardware radio transceivers in the iPhone 6s function on all major network infrastructures, i.e. GSM, CDMA and LTE.

So if you get a new iPhone from Apple you can take it to any network, right? Yep, technically that is true. But unfortunately yet again, the mobile device and service market isn’t that simple. Mostly because carriers don’t want it to be. Instead of installing software or incompatible hardware to lock devices to a specific network, carriers have a possible new opportunity to use specific radio spectrum bands to lock us to their networks.

Understanding Radio Spectrum Allocation

All wireless communication travels via radio waves. Those radio waves are divided into different bands that we call radio spectrum. In the US, radio spectrum is a public good owned by the government. The Federal Communications Commission (FCC) regulates all commercial spectrum and allocates specific spectrum bands to specific technologies, such as 3G and LTE. The FCC also allocates spectrum bands to industries such as TV broadcasting and satellite radio. Each industry can only use the specific bands allocated to it by the FCC to avoid interference with other industries and other networks.

The FCC only licenses more spectrum when necessary, meaning carriers can’t just get more spectrum when they want to expand their networks. Spectrum licensing is done through spectrum auctions held by the FCC. But spectrum auctions happen rarely, and not nearly often enough for US carriers that are in a constant race to offer the fastest network with the most coverage. So instead of waiting for auctions, sometimes carriers opt for partnerships with companies in other industries that use spectrum. Hence we are starting to see deals like the acquisition of DirecTV by AT&T.

When new bands are approved for mobile communication through mergers or partnerships, carriers and device manufacturers have to work together to create devices that function on these new bands. Take LTE for example. When MetroPCS first deployed LTE in the US there were only a few different LTE bands. Now five years later, all the major carriers have modified their networks, bought more spectrum and partnered with other industries opening up a flood of new LTE bands. When you take a look at the iPhone 6s specs you will see that it functions on some 20+ different LTE bands.

But wait a second. It looks like there are still multiple iPhone 6s models. If it's truly "carrier-free", shouldn't there just be one?

You’ll notice models A1633 and A1634 support one LTE band the others don’t: band 30. Back in 2012, AT&T acquired $600M worth of spectrum that was allocated to satellite radio communication. Later that year, AT&T and SirusXM radio submitted a request to the FCC to reclassify the spectrum for use in mobile communications like LTE. The FCC accepted the request and reclassified some of the underutilized satellite radio spectrum, which AT&T is now rolling out as LTE band 30. AT&T’s band 30 is super-fast since no other carrier uses it, and it reduces congestion across AT&T’s other LTE bands.

Radio Spectrum Effect On Devices

So what does this all mean for our mobile service and devices? AT&T officially began deploying LTE on band 30 last month. If you happen to live in an area where band 30 is already deployed and you bought a band 30 device, you’re currently experiencing data transmission bliss.

The new iPhone 6s models without band 30 do in fact work on the AT&T network using AT&T’s previously-licensed LTE bands 2, 4 and 17. Verizon and T-Mobile also use band 2 and 4. So Apple isn’t lying when it says its devices are “carrier-free”. And there are a handful of other devices out now that are similarly “carrier-free” with band 30 support, including the Nexus 6P and the Galaxy S6.

But AT&T’s band 30 reveals a potential new way for carriers to restrict consumers’ ability to switch networks. Will they try to create devices that only support their specific LTE bands?

They definitely could. It’s clear that some device manufacturers like Apple want true carrier freedom for consumers. Apple is building devices with receivers that function on CDMA, GSM and a whole slew of LTE bands so that we can switch carriers any time we want to.

What isn’t so clear is whether carriers will work with new phone manufacturers who don’t care so much about carrier freedom in order to build devices specific to their spectrum. If AT&T wants to partner with a manufacturer to create a device that only supports band 30, nothing’s stopping them.

So while all carriers support LTE technology now and devices are unbundled from service plans, we know there are more changes coming. We have seen mobile carriers go to great lengths to restrict the freedom of their customers, from two-year service contracts to arbitrary device locking. Now we are seeing upgrade programs coupled to service plans, so what’s to stop carriers from continuing to try to trap us in other ways? Not much, besides voting with our wallets to buy carrier-free devices from manufacturers who are transparent.

The complicated waters of industry mergers, radio wave classifications and spectrum auctions certainly make the constantly-changing mobile industry tough to navigate. The only way to keep carriers from crippling consumer choice is understanding service and devices. Hopefully device manufacturers won’t succumb to carrier pressure, but some will likely partner with carriers once again. It’s clear that carriers are losing at least some of their power with help from Apple and Samsung. As consumers it’s time we also cement our stance and continue to demand truly carrier-free devices.