If you’re looking for a new phone or even a new wireless carrier you’ve probably seen a few new acronyms being thrown around. Two of the most commonly used being CDMA and GSM. But what do they mean, why are they important, and what impacts do they have on you?
CDMA and GSM are the two global standards for telecommunication. CDMA stands for Code Division Multiple Access and GSM stands for Global System for Mobile. Neither is inherently better than the other but each has its own sets of strengths and weaknesses along with differences in technology that makes each unique.
In America, both technologies are used. If you have AT&T or T-Mobile as a carrier you are using a GSM network, if you are using Sprint, Verizon or US Cellular you are operating on a CDMA network.
Global System for Mobile is the most widely used mobile system. In fact, every country except the United States and Russia uses it exclusively. This is mostly because GSM was created and implemented first rather than any kind of technological superiority.
GSM networks rely on a TDMA, Time Division Multiple Access, to relay calls or other data over the network. This works by assigning time slots to each user and alternates between each interval while the devices are being used. This allows multiple devices to use the same frequency without interfering with each other. These intervals are also so small and they change so fast that we perceive them as a continuous stream of communication instead of hundreds and thousands of snippets.
Another important feature of GSM networks is the SIM cards that are in the back of phones. These store not only personal information such as contact information but also things such as your network identification and service subscription information. The pairing of these SIM cards with TDMA is what allows carriers to identify your device and your unique interval to allow you to use the network. One big upside to using a GSM network is that these SIM cards make it much easier to switch phones as so much information is stored in them and they are often compatible with other devices.
Code Division Multiple Access was developed during World War II to protect radio waves from being jammed by Nazis. This is why this technology can only be found in the United States and Russia. The reason other Allied powers do not use this technology is that in 1987 members of the European Union decided to make GSM their standard.
CDMA operates radically differently from GSM. Whereas GSM uses TDMA to separate users frequencies CDMA allows users access to the entire spectrum of frequency bands. They can use the entire spectrum because each call’s data is given a unique key and the receiver is able to read the key and divide the signals back into their original calls. Hence the name Code Division. This allows for not only more users on the networks but also for a more efficient use which translates to increased utilization.
One important thing to note is that many CDMA phones now have SIM cards in them. This is because these CDMA networks are implementing 4G and looking towards 5G networks where SIM cards are necessary.
What It Means For You
Despite all the technical mumbo-jumbo there really are very few actual differences between GSM and CDMA. Both can provide quality cell service to customers if the carrier has built a proper network. If you’re hung up on any worries over the quality of service it won’t be because of the type of network the carrier offers.
That being said there are advantages to say having a GSM network that offers SIM cards to backup information or make it easy to switch and upgrade phones. Otherwise, it would probably be best to just choose whichever carrier has the best coverage and call quality around you.