CDMA vs GSM (10 Differences explained)

CDMA vs GSM (10 Differences explained)

As technology develops everyday, the digital cellular technology also develops. With CDMA and GSM, most people don’t need to worry about which cell phone network they choose in terms of which technology is better although the two standards do diverge in important technical ways.

It is very important to get an international SIM card to avoid roaming fees when using these networks especially when travelling.

Further reading: What is international roaming?

What is CDMA & how it works

What is CDMA & how it works

CDMA (Code Division Multiple Access) is a cell phone service technology on old networks that are phasing out competing with GSM technology. CDMA refers to any of several protocols used in second-generation and third-generation wireless communications and it allows numerous signals to occupy a single transmission channel, optimizing the use of available bandwidth.

With CDMA, a technique is used whereby electromagnetic energy is spread to allow for a signal with a wider bandwidth. This allows several people on different cell phones to be connected over the same channel to share a bandwidth of frequencies.

In other words, CDMA enables many users to make use of the same band frequencies and permit to share without any interaction between the users while data and voice packets are separated using codes and then transmitted using a wide frequency range.

Advantages and disadvantages of CDMA

Here are some advantages and disadvantages of CDMA.


  • Has a very high spectral capacity to accommodate more users per MHz of bandwidth.
  • Call quality is better with more predictable sound.
  • CDMA has Better multipath execution.
  • The recurrence reuse plan is simpler to oversee.
  • It has Low force prerequisite.
  • CDMA has increment proficiency as it can serve more clients.
  • Easy to add many numbers of users.
  • No sense of handoff when changing cells.
  • Impossible for hackers to decipher the code sent.
  • It Works at an extremely low force level.


  • It can’t offer international roaming.
  • Quality of service decreases when the number of users increases.
  • Self-jamming occurs.
  • System performance degrades with an increase in the number of users.
  • The near-far problem arises.
  • Higher cost due to the greater equipment.
  • Reduce capacity because gradual transfer increases the use of radio resources.
  • The ability to upgrade or change to another handset is not easy with this technology.
  • A network of CDMA is not mature because it is relatively new with GSM.
  • Time synchronization is required.

Further reading: Benefits of a travel SIM card

What is GSM & how it works

What is GSM and how it works

GSM (Global System for Mobile Communication) is a digital cellular technology used for transmitting mobile voice and data services and is the most popular wireless cellular communication technique. This technology is currently the most widely used network technology in Internet of Things (IoT) applications for its simplicity, affordability, and accessibility, which may change in the next few years.

GSM uses a combination of Time Division Multiple Access (TDMA) and Frequency Division Multiple Access (FDMA). TDMA involves dividing a frequency band into multiple bands such that each sub-divided frequency band is allotted to a single subscriber, and FDMA involves allotting same frequency channel to different subscribers by dividing the frequency band into multiple time slots.

Advantages and disadvantages of GSM

Here are some advantages and disadvantages of GSM.


  • It provides very cost effective products and solutions.
  • It is easy to maintain GSM networks due to availability of large number of network engineers at affordable cost.
  • No roaming charges on International calls.
  • Worldwide connectivity and extensive coverage.
  • The phone works based on the SIM card so that it is easy to change the different varieties of phones by users.
  • It has the ability to use repeaters.
  • It is easy to integrate GSM with other wireless technology such as CDMA and LTE.
  • The GSM signal does not have any deterioration.
  • GSM is used all over the world with more than 450 million users.
  • SAIC and DAIC techniques used in GSM provide very high transmission quality.


  • It can interfere with certain electronics.
  • To increase coverage repeaters are required to be installed.
  • There is no end-to-end encryption of user data.
  • There are Several incompatibilities within the GSM standards.
  • Electromagnetic radiation is more with the use of GSM.
  • GSM provides limited data rate capability.
  • GSM uses FTDMA access scheme.
  • Macrocells affected by the multipath signal loss.
  • Bandwidth lag because of multiple users shares the same bandwidth.
  • Many of the GSM technologies are patented by Qualcomm and hence licenses need to be obtained from them.

Further reading: 7 health benefits of travelling abroad


Code Division Multiple AccessGlobal System for Mobile communication
Data speed rates is 3.6Mbps in CDMA.Data speed rate is 42Mbps in HSPA (3G).
CDMA is available in fewer countries and carriers.GSM is globally widely used and available.
CDMA does not support this feature.GSM supports transmitting data and voice both at once.
Customer information is stored in a headset or phone.Customer information is stored in a SIM card.
CDMA provides built-in encryption.GSM does not provide built-in encryption.
CDMS offers secure communication.GSM offers less secure communication.
CDMA transmissions are difficult to detect.GSM signals can be detected.
There are no such requirements for CDMA phones.There is always a requirement of SIM card for a GSM device to function.
CDMA technology is based on spread spectrum technology.GSM technology operates on a wedge spectrum known as carrier.

GSM & CDMA carriers

GSM carriers list

  1. AT&T
  2. T-Mobile
  3. ASTAC
  4. Big Sky Mobile
  5. Cellular One Nation
  6. DTC Wireless
  7. GCI Wireless
  8. Union Wireless
  9. Rogers
  10. Videotron Mobile

CDMA carriers list

  1. Verizon Wireless
  2. U.S Cellular
  3. Sprint
  4. Blue Wireless
  5. Bluegrass Cellular
  6. MTA Solutions
  7. Chat Mobility
  8. Clear Talk
  9. GCI Wireless
  10. Bell MTS

Further reading: 110 Top best travel apps

The future of CDMA & GSM

The future of CDMA & GSM

As networks continue to grow lately, it is very likely that the future will not look to bright for CDMA and GSM technology. It is with no doubt that providers are slowly shutting down CDMA but how will this impact customers? Carriers are actively working to move customers toward a newer technology because at this point 2G and 3G are inefficient allocations.

Same applies to GSM, field experts advice customers to walk away from CDMA and GSM and move to 4G or 5G. This means that 2G and 3G reception and call quality will likely be poor, even before the formal shutdowns. It’s a 4G LTE world now, with 5G coming up fast. No matter how much you love your old phone, it’s time to switch from CDMA and GSM as they will not be accurate in the future.


1. Is GSM better than CDMA?

Neither GSM nor CDMA is technically better as they ultimately provide the same service, and the quality of a network depends on the carrier, not the cellular standard used.

2. What is the main difference between GSM and CDMA?

The GSM technology offers less security as compared to the CDMA technology.

3. Is CDMA used in 4G?

No, CDMA is a set of protocols used in 2G and 3G mobile communication networks.

4. Is CDMA safer than GSM?

GSM based phones emit 28 times more radiation as compared to CDMA phones and continuous exposure to radiation can affect your health. So, CDMA phones are considered safer than GSM.

5. What is the use of GSM?

GSM provides basic to advanced voice and data services including roaming service and supports more than one billion mobile subscribers in more than 210 countries throughout the world.