That old thing? Oh, it's just always been here, and we never got rid of it.

July 3, 2011 10:49 AM

A question about cellular networks and deployed cellular technology in the US.

I've noticed that my 3G smartphone occasionally drops to "1x" coverage. And this Wikipedia article states that "Verizon supports the 3 generations of CDMA (IS-95, 1x, and EV-DO) networks and now its newest 4G LTE service..." This got me thinking: why aren't cellular carriers racing to get rid of all of these old technologies? Why do they maintain old standards for years? I'll just talk about Verizon, but this question applies to all of the major US carriers.

I clearly have no background when it comes to cell networks, but it seems that maintaining the old technologies would come with a lot of costs: additional antennas, additional servers to feed data from old technologies into Verizon's pipes, hiring and training people who can maintain the old standards. It also has an impact on Verizon's devices and device makers: they have to include chips and antennas that can handle all 3 versions of CDMA as well as adding LTE support to the 4G phones.

You'd think that all of the added difficulty and cost of maintaining a national wireless network with 3-4 different technologies would drive Verizon to go all-EV-DO as the "base" standard as quickly as possible, with an eye on going all-LTE in the next couple of years. There is the problem of customers' old phones not working anymore, but now that Verizon's EV-DO coverage is rolled out extensively it seems they would be starting to retire the old technologies. It also seems that most phones would be replaced in 2-3 years, so Verizon could just inform all of their device makers that all devices sold in year X must use EV-DO because the older networks are going away in year X+2.

So: why is there no rush to retire old phone standards? Why are we not quickly headed to an all-3G world?

posted by Tehhund to technology (10 answers total)

There is almost no upside to tearing out a network that has already been built up.

The downside is: you have to pay people to tear out old equipment that is already there and still working, you piss off old customers, and you mess up more legacy technologies. There are a lot of devices (alarm systems, weather monitoring) that may have been installed before 3g, that are still working fine.

The cellular marketplace is more than just people buying new phones every two years.

Not to mention, the redundancy. The older technologies tend to have farther reach than the newer faster ones, so when a customer is on the fringes of reception for 3g, they fail down to 1g instead of down to nothing.

As for support/maintenance, yes, there are costs involved. But in a lot of cases, they can just redeploy old equipment when in-place equipment breaks.

As for servers and backhaul, that's not really an issue. The old antennas can plug into the new networks.
posted by gjc at 11:08 AM on July 3, 2011 [1 favorite]

This is purely anecdotal, but I know a few people at my place of work who still have cell phones that are five years old or older. As long as that is the case, companies must maintain the networks that those phones run on - they can't force people to abandon their phones, even if they want to (which I would think they do, for all the reasons you list).
posted by pdb at 11:09 AM on July 3, 2011

The biggest one is cost, and two-fold:

Large mobile networks have lots of customers with equipment that only works on the older technologies. Requiring all of those subscribers to take time out of their schedule to trade in a phone that the subscriber still uses will result in a decent minority of those subscribers changing companies. That says nothing of the cost of actually getting the devices to put into the hands of the subscribers who will swap equipment. It can be done, but inertia and an unwillingness to risk massive subscriber losses. A long-term customer who only pays $20/month but uses virtually no resources and never calls customer service is more profitable than someone under contract with the latest smartphone and demanding more of the mobile network.

Second, the older technologies have already been tested and deployed over a period of years. A lot of manpower and capital expenditures in equipment are required to switch over the entire network to a brand new technology. If the old equipment was turned off without replacement, the existing network would now have a lot of holes and reduced service area. Witness AT&T with its coverage problems, and no mobile network provider wants to be in that situation. Plus, the new equipment may require new transmission and receiving equipment, possibly new antennas, etc. All of these have to be approved by the FCC. After all that, if there's no space available at the current tower locations for new equipment then the provider has to go through the very arduous and NIMBY-infested process to get a new site approved.

On preview: Yes, a mobile provider can force a subscriber to swap devices. AT&T (previously Cingular) and Verizon both did it years ago when they closed down the AMPS/TDMA service. Phones that couldn't talk GSM or CDMA were effectively booted off the network. Mobile providers don't like to do this, due to the foregoing, but it has been done.
posted by fireoyster at 11:13 AM on July 3, 2011 [2 favorites]

In the case of Verizon* EVDO is simply a add-on to CDMA (or 1x as your phone shows it) so it's still the same network. The 1x towers simply haven't been upgraded to EV for whatever reason (capacity on their backbone, cost vs. people covered, etc); and likewise all EV phones are automatically 1x phones; it's still the same tech (just a newer rev), the same chip handles it all. It's worth noting that in the US, nearly all of the CDMA chipsets in phones on the market come from a single vendor, Qualcomm (who also is the standard bearer for the tech).
posted by ConstantineXVI at 11:14 AM on July 3, 2011 [1 favorite]

Whoops: "...inertia and an unwillingness to risk massive subscriber losses prevents this absent extreme circumstances."
posted by fireoyster at 11:14 AM on July 3, 2011

Also, old networks are being shut down to an extent. For AT&T's UMTS (the 3G successor to GSM, and unlike the 1x/EV relationship, a separate network/tech), I understand they've been shutting down and/or turning down the power on some of their GSM sites so they can deploy UMTS in the same spectrum. And the reasons AT&T hasn't shut down GSM yet:
1) UMTS is not backwards-compatible with GSM, so GSM phones would go dark (where 1x phones just run as slow as they always have)
2) Their UMTS footprint doesn't yet match their GSM footprint, so they'd take a serious coverage hit.
posted by ConstantineXVI at 11:21 AM on July 3, 2011 [1 favorite]

Just as illustration of gjc's explanation, the first cell networks built in the mid-late 80's were analog (AMPS). In the United States, these were required by the FCC to be supported until 2008. Though they'd long been obsolete in the consumer cell phone market, businesses and consumer services (like OnStar) still used the generally most-pervasive network right up to the bitter end.
posted by t_dubs at 11:32 AM on July 3, 2011 [1 favorite]

Also, in some cases supporting the old alongside the new isn't going to be that large of a cost. They almost certainly share a lot of costs (real-estate rent, towers and antennas, power and backhaul, permitting and community acceptance, etc). Keeping an older transmission scheme available may require as little as an extra card in the base station or even just some extra software in its DSP. This depends on how similar the new and old technologies are, of course, but the new ones are designed to be able to coexist with the old during rollout.

Also as a few people have said, it's not just that there are zillions of customers on 1x-only phones; it's that a lot of them are embedded or specialized devices that can't easily upgrade.
posted by hattifattener at 12:32 PM on July 3, 2011 [1 favorite]

I use Verizon because of the CDMA network. I get coverage in places that GSM providers still haven't gotten out to. That CDMA network was built out over a lot of time, and when you are covering 60 miles just to get to the next town, you don't care what kind of network you're on as long as you've got coverage. So there's the issue of the old network already serving areas because of its existing infrastructure. Then there are also considerable costs to upgrade that infrastructure to the newest tech. If I'm far out in the middle of nowhere, I'm not going to care that they haven't upgraded as long as the phone works.
posted by azpenguin at 2:47 PM on July 3, 2011 [1 favorite]

It is my understanding that Verizon doesn't build their own towers...they use towers owned by other companies (Sprint is one I am aware of). Plus, they bought Alltel a year or two ago, so they inherited whatever towers Alltel had. Could that have something to do with Verizon's approach to wireless technology?
posted by MultiFaceted at 9:00 PM on July 3, 2011