SmartSIM Speculation

According to new research, the best provider of wireless service in the US might soon be TracFone, a US subsidiary of Mexican telecommunications giant America Movil.

Wait what?

That’s the opening of a recent post by Mike Dano of Light Reading. Dano is referencing a service called SmartSIM that TracFone recently teased. TracFone hasn’t shared many details yet, but it looks like SmartSIM will allow subscribers’ phones to automatically switch between multiple networks based on the signal strength of each available network.

Dano references a simulation conducted by the network analysis firm Tutela. The simulation suggested TracFone’s SmartSIM service might outperform each of the major U.S. networks. Not many details are shared about the methodology behind the simulation. To Dano’s credit, he acknowledges the simulation shouldn’t be taken too seriously:

Again, SmartSIM today remains only a possibility rather than a concrete offering, and so drawing any firm conclusions about the service at this point is more of an exercise in mental gymnastics than actual forecasting. But, considering many of the pieces are falling into place for a service like SmartSIM from TracFone or someone else, it’s worth giving the topic some thought.

I’m guessing Tutela made several assumptions in its simulation:

  • SmartSIM can access all four major U.S. networks
  • SmartSIM subscribers are not subject to any severe, adverse throttling or prioritization on any network
  • The technology can reliably determine the quality of each available network
  • Network switching will be determined on the basis of service quality alone (irrespective of TracFone’s financial incentives)

Some of these assumptions are probably inaccurate. In particular, I don’t think TracFone will have an easy time working with all four of the major network operators. While TracFone currently offers service over each network, new legal arrangements and technical capabilities will need to be sorted out with network operators before SmartSIM-style network switching is possible. I don’t think Verizon or AT&T will agree to arrangements that allow TracFone to offer better service than their own networks can provide.

Despite my skepticism, I’m still excited about the potential of dynamic network switching, eSIM technology, and SmartSIM-like services.

Tutela’s October 2019 MVNO Report

In October, the network evaluator Tutela released its USA State of MVNOs report. Most network evaluators only assess the performance of the Big Four carriers (AT&T, T-Mobile, Sprint, and Verizon), so it’s interesting to see Tutela assessing a wider range of carriers.

Near the beginning of the report, Tutela shares some reflections on how the MVNO landscape is changing:[1]

MVNOs and MNO flanker brands in the US carved out a niche largely serving the needs of lower-income customers or those with particular data needs…in 2019, the landscape is rapidly shifting. Technological advancements have made the barrier for operating some kind of network much lower; the entrance of cable companies into the market have pushed MVNO service into the more lucrative postpaid segment; and multi-network MVNOs are innovating on the network side of the equation, rather than solely differentiating on price or customer service.

Methodology

The approach Tutela used to evaluate MVNOs was in line with its usual methodology. The company crowdsourced performance data from typical consumers with the help of code embedded in Tutela’s partners’ apps. In the new report, Tutela primarily considers how well MVNOs performed in regions where at least three of the big four networks offer coverage. Tutela calls these core coverage areas.[2]

Within core coverage areas, Tutela calculates the amount of time subscribers have service that exceeds two different quality thresholds. When service exceeds the “excellent” threshold, subscribers should be able to do highly demanding things like streaming high-definition video or downloading large files quickly. When service exceeds the “core” threshold, subscribers should be able to carry out typical activities like browsing or streaming music without trouble, but performance issues may be encountered with demanding activities.

Results

Here’s Tutela’s visualization of the main results:[3]

Tutela results


A chart of median download speeds shows a similar ranking among carriers:

Tutela Download Speeds

The results aren’t too surprising. Verizon MVNOs come out near the top of the hierarchy, while Sprint MVNOs tend to come out near the bottom. Cricket Wireless has a good score for the core threshold but does poorly in terms of the excellent threshold. That outcome makes sense since Cricket throttles maximum speeds.

Possible selection bias

I often write about how assessments of network performance that use crowdsourced data may be vulnerable to selection bias. These results from Tutela are no exception. In particular, I wonder if the results are skewed based on how high-quality phones used with different carriers tend to be. In general, newer or more expensive phones have better network hardware than older or cheaper phones.

Xfinity Mobile takes the top spot in the rankings. Xfinity Mobile is a new-ish carrier and is restrictive about which phones are eligible for use with the service. I would guess the average phone used with Xfinity Mobile is a whole lot newer and more valuable than the average phone used with TracFone. Similar arguments could be made for why Spectrum or Google Fi may have an advantage.

To Tutela’s credit, the company acknowledges the possibility of selection bias in at least one case:[4]

The second factor explaining Google Fi’s performance compared to Metro or Boost is the device breakdown. Although a broad range of Android and iOS devices work with Google Fi’s service, the network is targeted most heavily at owners of Google’s own Pixel devices…The Pixel devices use top-of-the-line cellular modems, which intrinsically provide a better cellular experience than older or mid-range devices.

Wi-Fi results

Several MVNOs offer access to Wi-Fi hotspots in addition to cellular networks. I’ve been curious how much data carriers send over Wi-Fi, and Tutela’s results give an estimate. While Xfinity Mobile appears to have sent the largest share of its data via hotspots, it’s a smaller share than I expected:[5]

Tutela data suggests that Xfinity Mobile has already succeeded in offloading over 6% of smartphone data traffic onto its Wi-Fi network – far more than any other network.

Tutela also shares a graph comparing hotspot usage among different carriers:[6]

Graph of wi-fi usage share among multiple carriers

Other stuff

There were a few other bits of the report that I found especially interesting. In one section, the report’s authors reflect on the fast growth of MVNOs run by cable companies:[7]

Xfinity Mobile and Spectrum Mobile captured nearly 50% of the postpaid subscriber growth in Q2 2019, and combined added nearly as many postpaid subscribers as host network Verizon.

In another part of the report, Tutela shares a map displaying the most common host network that Google Fi subscribers access. It looks like there are a decent number of areas where Sprint or U.S. Cellular provide the primary host network:[8]