A look at the wireless industry's shuttered networks: From CDPD to iDEN to CDMA to WiMAX

Network shutdowns are a way of life in the wireless industry, as technologies evolve and advance, and one era gives way to the next. Wireless carriers have been shutting down legacy networks for more than a decade and the shuttering will continue this year.

Just last month T-Mobile US (NYSE:TMUS) shut down MetroPCS' legacy CDMA network, and in September AT&T Mobility (NYSE: T) will do the same for the CDMA network it inherited from Leap Wireless. Meanwhile, Sprint (NYSE:S) confirmed last year it will shut off service on its mobile WiMAX network on or around Nov. 6, 2015.

The phenomenon is not unique to the U.S. For example, in Europe, Telenor Norway CTO Magnus Zetterberg said last month the operator plans to completely decommission its 3G network in 2020, five years before it shuts down its 2G network in 2025.

Wireless carriers shut down legacy networks for a variety of reasons. Sometimes, it's simply that newer and more advanced technologies have arrived and customers no longer use the older ones. Other times carriers inherit legacy networks and look to shut them down for cost savings. Many operators refarm spectrum that had been dedicated to older services and repurpose the airwaves for newer ones.

The following rundown of network shutdowns is not meant to be comprehensive, and tilts heavily toward U.S. carriers that have shuttered networks or plan to do so. There are many other aging technologies that have been passed by (Mobitex and Reflex paging networks being two of them). However, the list shows when and why carriers have consigned certain network technologies to the scrap heap of history while remembering what the networks were used for in the first place.

Did we miss any network shutdowns? What's your favorite legacy technology? Please let us know in the comments! --Phil

A look at the wireless industry's shuttered networks: From CDPD to iDEN to CDMA to WiMAX