Compare CDMA Cell Phone Plans

What is CDMA?

CDMA stands for Code Division Multiple Access. It is a technological method for ensuring that the calls from a cell phone get to the right target and come out sounding correctly. CDMA is a rival to a different such method, which is called GSM. GSM stands for Global System for Mobiles. These two standards have different origins and different companies use them today, but to understand their place today, it is important to track their evolution over the past several years. In brief, CDMA is popular in the US, and GSM is the standard for the rest of the world.

GSM originated in 1987, when the governments of Europe and telecom industry firms decided to choose that standard and adapt it worldwide. All companies that were moving from analog to digital systems for calling jumped on board. Later on, in the mid-nineties, Verizon and Sprint were moving from analog to digital systems as well. However, at that time, CDMA was the new and advanced standard, so those two companies chose CDMA instead of GSM. As a reminder, you can compare cell phone plans of all kinds, not just CDMA, using Wirefly's comparison engine.

That choice was happenstance, but it has had major implications for cell companies and their offerings ever since. There are some major differences in the standards. First of all, they just work differently. GSM operates by assigning each receiving phone a certain time slot and routing signals to the phone based on that time slot. CDMA instead codes every call and then gives the recipient phone the unique key to the right coded data. The CDMA approach takes more power, but it is stronger and more flexible. From a technological perspective, CDMA is superior. GSM does have a few advantages, though. For example, if you are in a GSM network and you want to switch phones, you can just take your SIM card out and put in in the new phone. It is as simple as that. By law, GSM phone carriers must accept and serve any phones that use GSM, so there is no difficulty involved in moving between carriers. CDMA is not as convenient. You cannot just move your SIM card to a new phone and start using that phone. Under CDMA, carriers have no obligation to take a new phone that shows up on their network- they can deny that phone any access to the network, and frequently they do. Verizon and Sprint have no interest in letting rival phones onto their networks for no obvious gain.

The story of GSM and CDMA does not end there. The description and history above was for the movement from analog to digital phone signals. This is the transition from 1G to 2G. The movement from 2G to 3G was a little more complicated. The issue at hand is that GSM's clock-based system for tracking calls is not as good as CDMA's encoding system. That means that the 3G edition of GSM is actually a form of CDMA. By now, most consumers have phones that can access 4G networks- the most recent generation of phone communication and information. The 4G LTE form of network is widespread across different carriers, although they frequently are not compatible with each other.

On a worldwide level, GSM is still more popular. The CDMA standard is only really popular with Verizon and Sprint. That still covers a lot of customers, but complications arise when those customers need to travel abroad or want to switch to a different carrier that uses GSM, In general, it is not hard to go from GSM to CDMA, but the opposite case is a lot harder: moving from GSM to CDMA means the new network may not accept your phone, forcing you to buy a new phone in the CDMA system.

Deciding on what kind of network you would rather use is a hard decision to make. At this point, both kinds of networks deliver good performance. It is the individual company that decides on the features and plans that make their offerings attractive. It is also important to note that GSM and CDMA are standards, but every company involved uses a customized solution to change the standard to meet their needs or to add more features.

Although CDMA was more advanced at the time Verizon and Sprint were moving from 1G to 2G, GSM has since caught up or even passed CDMA in terms of being able to deliver a better connection. However, the recent arrival of 4G has generally meant that telecoms companies are now in a race to build out new 4G infrastructure. 4G is certainly going to be the standard of the next few years, at least, so it pays to get into 4G now.

CDMA or GSM?

If you are trying to figure out if you would rather get CDMA or GSM, then you should put the question aside. The differences in the standards from a consumer viewpoint are very small. There are much more important things to settle before the network standard of a phone. For example, each company offers its own array of phones and phone plans, so the availability of your favorite phone at a good price matters much more than CDMA or GSM. This is especially true when you take into account the fact that things are moving toward 4G, where networks are even more similar.

One of CDMA's nastier features is the fact that the carrier has a lot of control over the phone. They can determine which phones can work on their networks. That trend actually continues in 4G even though the technology is very different. For example, Verizon sells 4G phones, but they require Verizon-based software in order to make calls. The carriers still want to maintain as much control over the phones as they can.

Related: GSM vs. CDMA

If you are thinking about getting a new phone, then the pricing of the phone itself and the available plans matters much more than the network standard, so don't worry too much about whether a phone is CDMA or GSM. The one time this may become important is if you plan to do much traveling outside the US. There are now some CDMA phones that can work with GSM networks if necessary, but not all phones are capable of doing this. You should expect that you will need to buy a new phone if you want to change plans and carriers in the future. The current trend is for 4G-capable phones to work on each other's special 4G networks, but as of now this is a patchwork of different versions of 4G standards across different carriers. Things may settle on a 4G standard that is common between GSM and CDMA in the future, but for now that is not the case.