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?