15 Differences between GSM and CDMA

15 Differences between GSM and CDMA

15 Differences between GSM and CDMA

 You may have heard the terms GSM and CDMA which are commonly discussed in conversations about cell phones, but what do they mean and what are the differences between GSM and CDMA?

GSM and CDMA are two radio technologies used by carriers around the world. They are the most prominent technologies in the 2G and 3G era. Different phones support one or both, but it's important to know that they are different.

If you are wondering about the differences between GSM and CDMA and whether GSM is better than CDMA or vice versa, you have come to the right place. So without further ado, let's discuss the differences between the two.

What is GSM?

What is GSM

GSM stands for Global system for mobile. It is a cellular communication technology that allows the transmission of various voice and data signals over a common communication channel but in different time slots.

GSM uses a Subscribers Identity Module (SIM) card as its main element. This is because each device in the network has its own specific SIM card. Thus the various GSM technology subscribers are differentiated by SIM. However, at any time a user can switch from one SIM card to another thus offering more flexibility.

A tower on the network acts as a control center for mobile devices in that area. And the network stores the information of each device with the help of a specific sim card number.

In the case of the GSM technique, signals are transmitted in different time slots so that the full channel can be used for signal transmission. This is the reason when a call is made to a certain number then no other calls can be connected to that particular number within a certain duration. This happens because in that time slot a signal is transmitted and thus makes the time slot busy.

So, each subscriber on a GSM network holds their own SIM card which has a specific identity, algorithm and authentication key associated with it.

What is CDMA?

What is CDMA

CDMA stands for Code Division Multiple Access which was originally known as IS-95. This is the technology that forms the basis of 3G mobile phones and was originally developed by Qualcomm. CDMA systems offer complete bandwidth utilization, by offering a unique code for each signal to be transmitted over the full channel bandwidth. Thus the various CDMA signals transmitted over the channel are differentiated by different codes. Therefore, it uses direct sequence spread spectrum modulation with mixed CDMA detection.

Basically, in CDMA technique, each signal in the channel is assigned a separate propagation code. This code helps differentiate the different signals present on the channel. A group of orthogonal codes is generally used to detect signals at a receiver.

The base station of the CDMA station stores different codes, so that when various signals are received from several base stations, the base station differentiates the signals with the help of orthogonal spreading codes. The use of orthogonal codes minimizes the possibility of interference. Thus we can say, in the case of CDMA, each frequency is used by all users in the network but each holds a different code.

Unlike GSM, CDMA never uses a SIM card. However, authentication in the case of CDMA is done based on a separate ESN which is present in each mobile device itself.

Difference between GSM and CDMA

After you know the explanation of GSM and CDMA. Maybe now you are curious about the difference between the two. Here are some differences between GSM and CDMA:


1 GSM stands for Global System for Mobile Communications. CDMA stands for Code Division Multiple Access.

2 GSM is based on a spectrum wedge called a carrier. CDMA is based on spread spectrum technology.

These 3 operators are divided into time slots, and each user is assigned a different time slot. Thus, until the ongoing call is finished, no other users can access the same slot. This technology allows each user to transmit across the entire frequency spectrum around the clock.

4 Less security when compared to CDMA technology. The security is better when compared to GSM technology.

5 No built-in encryption. Has built-in encryption.

6 The signal can be detected because the GSM signal is concentrated in a narrow bandwidth. Signals cannot be detected easily in CDMA.

7 The GSM network operates on the 850MHz and 1900MHz frequency spectrum. CDMA network operates in the 850MHz and 1900MHz frequency spectrum.

8 GSM is used by more than 80% of the world's mobile networks. CDMA is exclusively used in the United States, Canada and Japan.

9 GSM uses EDGE data transfer technology. CDMA has faster data transfer because it uses EVDO ready data transfer technology.

10 It offers a maximum download speed of 384 Kbps. It offers a maximum download speed of 2 Mbps.

11 A SIM card is required for GSM device operation. CDMA phones do not use a SIM card to operate.

12 GSM is more flexible than CDMA because the SIM can be swapped with other GSM devices. CDMA is not flexible.

13 GSM telephones transmit pulses of continuous waves. Thus, there is a need to reduce exposure to electromagnetic fields. CDMA phones do not have this feature.

14 GSM allows limited roaming CDMA allows worldwide roaming.

15 The average GSM phone emits 28 times more radiation than CDMA. Radiation is much lower than GSM

GSM Vs. CDMA: Which Is Better?

This is one of the frequently asked questions by mobile users, but to answer this question is not as simple as one might think.

GSM and CDMA are different ways of achieving the same goal. The fact that a very popular network is built into every network proves that it is the quality of the network, not the standard, that matters. For example, in the United States, two of the four major carriers (Verizon and Sprint) use CDMA while the other two (AT&T and T-Mobile) use GSM.

Technically, neither is better in terms of quality, but there are a few things here for your consideration. GSM phones can be unlocked and moved between carriers, but CDMA phones are often locked to one carrier and cannot be transferred.

Also, depending on where you buy your phone, it could come in a GSM or CDMA model, or both. It all depends on which carrier is available in your area. A GSM provider may be better at covering some areas, while a CDMA provider will have better coverage in others.

How To Check GSM And CDMA Network Compatibility?

You have to be careful while checking the network compatibility of the phone. Phones sold in markets catering to both standards often come in either a GSM version or a CDMA version, but most are compatible with both.

If you bought a CDMA phone from a third-party retailer, you will have to contact your carrier to activate it. If you buy a GSM phone, you will have to buy a SIM card to insert into your phone which will activate the network capabilities of the phone.

CDMA phone owners don't have to worry about the SIM card, but this causes CDMA phones to have compatibility limitations that are difficult to overcome, while GSM owners can simply remove their SIM and replace it with another carrier.

Most CDMA networks do not allow the use of a phone originally purchased from another carrier, even if the phone is technically compatible. This is an important limitation to remember when using CDMA networks. If you decide to switch networks later, you may need to buy a new phone even if the network you are switching to also uses CDMA. This is one of the reasons why you should get an unlocked phone.

Even though GSM is more open, the frequency band supported by the phone can still limit access. Some frequency bands range from 380 MHz to 1900 MHz, and the band used may vary from market to market. Therefore, you should double-check your local carrier's band usage and make sure the phone you're buying supports the same.

Thus, GSM is concentrated around a core of four bands, namely 850, 900, 1800, and 1900. Phones supporting all four bands can be used in most countries, which is why GSM phones compatible with all four bands are often called "world phones". .


Although based on GSM principles, LTE is a standard unto itself that operates independently of the existing GSM and CDMA networks, it is the true fourth generation of mobile data that we usually call 4G.

South Korea initially led the breakthrough of 4G LTE, but many countries, including Indonesia, have since followed suit. This standard uses the SIM card to switch networks by changing the SIM if the phone is compatible with the new network.

In the early days of 4G LTE, it was only used for data but not voice. Unfortunately, this means the owner of the CDMA/LTE phone is still network locked.

However, that has changed with the launch of Voice over LTE (VoLTE), which allows users to make calls over a 4G LTE network. The downside is that not all operators around the world support VoLTE. In this case, as long as 4G LTE coverage is available, calls will still be handled by CDMA or GSM technology.

In Indonesia, many operators support VoLTE technology, so as long as your cellphone is compatible, you will be able to make clearer calls than regular calls over 2G/3G networks.

4G LTE rose to become a global standard for 4G and is available in various parts of the world including Indonesia. While more comprehensive coverage is nice, there are also issues with 4G LTE spectrum. Remember how GSM/CDMA operates on so many different bands? The same goes for LTE. You need to check that the compatibility of the phone matches the frequency band supported by your carrier. You will not be able to use your LTE phone on another network with the same standard but a different frequency band. Thus, the more bands a phone supports, the better.


So that's the difference between GSM and CDMA. In short, both GSM and CDMA are technically better. They ultimately provide the same service, and the quality of the network depends on the carrier, not the cellular standards used. GSM phones can be unlocked and switch carriers, whereas CDMA phones are locked to carriers. It's usually cheaper to buy an unlocked GSM phone than a contract CDMA phone.

Don't forget to check what band your chosen phone supports carefully. Some work on GSM or CDMA, but most support both standards and offer several different frequencies globally. But by switching to the global LTE standard, you don't have to worry too much about CDMA and GSM. Currently, they are only relevant in cases of poor LTE coverage.

GSM and CDMA will remain irrelevant as carriers around the world shift to newer mobile network technologies such as 5G and, eventually, 6G.

________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ ________

That's all the difference between GSM and CDMA articles. Look forward to other interesting articles and don't forget to share this article with your friends. Thank you…

Resa Risyan

Just an ordinary person who wants to share a little knowledge, hopefully the knowledge I provide can be useful for all of us. Keep in mind! Useful knowledge is an investment in the afterlife.

Also, read the article about 15 SEO Tips To Increase Your Rank In Search Engines. And see you in another article. Bye
Read Also :
DotyCat - Teaching is Our Passion