T-Mobile Will Increase Premium Data Allowances. It's Bad News For Most Subscribers.

T-Mobile just announced a handful of upcoming changes to a few of its unlimited plans. Journalists covering the news are praising the carrier’s decision to offer unlimited Premium Data on the Magenta MAX plan. I think these journalists are falling victim to the bullshit T-Mobile filled its press release with:

Legacy smartphone plans are built for lower capacity 4G LTE networks, so Verizon, AT&T and even T-Mobile’s unlimited plans allow providers to lower your network priority if you’ve used a massive amount of data, which means that you might hit speed bumps if the network gets congested. Verizon and AT&T market this as ‘Premium Data’ and give most customers 50GB. But, there’s nothing premium about paying more for fast 5G that’s only in ‘some parts of some cities.’* Now we’re in the 5G era, and T-Mobile has lit up the highest-capacity 5G network available — a network so powerful it can start unleashing the power of 5G to deliver unlimited Premium Data.

Let’s unpack that.

First, T-Mobile is giving way too much credit to 5G. Most of T-Mobile’s customers don’t even have 5G-compatible phones. Premium Data is still available to customers limited to 4G connections.

Second, deprioritizing ultra-heavy data users is a pretty efficient way for network operators to manage resources. Under the usual 50GB-ish per month thresholds, only ~1% of unlimited plan subscribers use enough data to get deprioritized. Users that T-Mobile deprioritizes will experience slower speeds when network resources are under heavy demand. However, deprioritized users can still experience normal speeds when networks aren’t under a heavy load. According to T-Mobile’s own website, deprioritization usually doesn’t have practical consequences (emphasis mine):

Where the network is lightly loaded in relation to available capacity, a customer whose data is prioritized higher than other traffic will notice little, if any, effect from having higher priority. This will be the case in the vast majority of times and locations.

I guess you could say T-Mobile’s Premium Data is only useful in “some parts of some cities.”

The utility of Premium Data hinges on how much Premium Data is being used by other network users. By including unlimited Premium Data with the Magenta MAX plan, T-Mobile is slightly degrading service quality for tens of millions of users in order to improve service for a tiny fraction of the company’s heaviest data users. In my view, it’s a bad tradeoff from a network management perspective. T-Mobile is choosing to make the tradeoff because it gives the company a new perk to advertise on its most premium plan.