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Unlocked Devices: The Technological Realities

We’ve already addressed the topic of unlocking devices in FCC filings (such as this onePDF) and blog posts, including this one that offers a list of unlocked devices available today. But as an engineer who has dealt with these issues at Bell Labs from the industry's early days, I felt it was important that I explain some of the technological challenges that exist with unlocked devices.

The engineering reality: An unlocked phone doesn't necessarily mean an interoperable phone, or one that you can take to any carrier that you want and here's why.

As you know, wireless technology relies on spectrum, which are the radio frequencies designed for specific uses. When spectrum is purchased at auction, the bands are divided into useable sections. Since the spectrum allocation is different, there's no uniformity in the U.S. across all of the carriers. Quite simply, there is no device that could work across all bands, allocations and technologies. In order to create such a device, it would be much bigger than we're accustomed to since it would have to include a number of radios and corresponding parts that increase size and reduce battery life (think Gordon Gekko phone or for those of you who are younger, Zack Morris phone).

In the U.S., there are a variety of "flavors" of technology too. There's GSM, GPRS, CDMA, EV-DO, UMTS, HSPA (and HSPA+), LTE and soon VoLTE. These technologies sometimes work with other carriers, but sometimes, there may be devices that may only work in a carrier-specific band of spectrum.

To add to the different technologies then there is the identity management structure. Mobile devices that may operate on carriers' networks may use SIM, IMSI, and IMEI, where others may use MEID and ESN.

As if this wasn't complicated enough with the different networks and identity management, there's also operating system, device hardware, security, optimization and cloud differences. Here's a quick explanation of each one of these:

  • Operating Systems – Public mobile networks may be at different releases of OS and have OS variations across networks, which may cause incompatibilities
  • Device Hardware – Networks may have a variety of device hardware vintage interoperability, which simply means it may impact how a device interacts with the network
  • Security Solutions – Carriers may use a variety of security solutions to protect networks and offer proprietary products to their customers too (e.g., anti-virus, VPN, etc)
  • Optimization: Phones are optimized for a particular carriers' network, for example, towers and data roaming partners
  • Cloud-back-up – If consumers choose to store information on the cloud, the different cloud options may prevent someone from transferring that information to another carrier (e.g., restore to device from carrier A cloud over carrier B network)

Yet these are only a few of the technological challenges that exist for the post-paid (or contract) and prepaid consumers. In addition, those who rely on prepaid wireless services typically cannot transfer their devices to another carrier. Prepaid providers may not allow individuals to bring in their own devices either due to the proprietary software used to manage the customer's usage or customized features (e.g. parental controls).

It's thanks to the diversity and highly competitive nature of the U.S. wireless market that consumers have benefited greatly since the U.S. leads the world in 4G/LTE and smartphone deployment. At the same time, it also means that we have some challenges associated with the wide variety of options that ought to be considered so that consumers will have realistic expectations about what is possible when unlocking their devices.

2 Responses to “Unlocked Devices: The Technological Realities” Leave a reply ›

  • avatar

    While this article is factual that phones may only operate in full or part when switching between carriers, it does not provide the full picture on the damage that restricting cell phone unlocking provides to consumers at the benefit of increased profit for cell phone carriers and device manufacturers. Blocking cell phone unlocking is all about driving more profits for the big companies.

    1) For starters, lets state the fact that typically one can take nearly any AT&T phone that is unlocked and pop a T-Mobile SIM card into the phone and get some level of working telephone service. Not all bands may work, but for certain customers this may be adequate for basic calling / basic data services. I see no reason why we shouldn't allow the consumer to make the choice here if they find the services adequate with the devices they own. This should not be the choice of the operators or the government to make.

    2) Unlocked cell phones can be resold by consumers after they meet contract requirements. This gives consumers another path to exit a relationship with one carrier and enter another while recapturing some of their investment on the previous device which they technically paid for over the course of their contract. Blocking consumers from this basic right only benefits the carrier and phone makers; it makes it harder and more expensive to switch if you can resell your old phone.

    3) Unlocked cell phones are also beneficial to mobile software developers who often need to buy multiple phones to test with. Buying brand new unlocked phones is expensive and this law hurts small and medium sized mobile developers who are now forced to spend tons and tons more for phones just for testing that could formerly be bought on the secondary market used.

    4) Blocking unlocking of a consumers phone prevents them from using the phone with another operator's sim card when they travel overseas. Anyone who has traveled to Europe over the past 10 years knows this practice is a normal behavior for users, but now they are forced to rent a phone, or be forced to pay very expensive international rates to their existing mobile carrier rather than just using a different sim.

    These are just a few of the many reasons we should not look at just the technology limitations as a means to justify this damaging restriction of blocking unlocking of cellphones and how it impacts consumers. Consumer rights should be held above big company profits by our government.

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