Difference Between GSM and CDMA

Contributor: 

Shivam Mathur

GSM (Global System for Mobile Communication) and CDMA (Code Division Multiple Access) are two dominant technologies for mobile communication. These two technologies differ in the way calls and data travel over the mobile phone networks take place. On comparing both the technologies GSM has some limitation when the call quality is concerned but still has more flexibility and an easy implementation relative to the CDMA technology. The major difference between the two lies in terms of the technology they use, security factors, their global reach and the data transfer speeds.

1.      Technology

The CDMA is based on spread spectrum technology which makes the optimal use of available bandwidth. It allows each user to transmit over the entire frequency spectrum all the time. On the other hand GSM operates on the wedge spectrum called a carrier. This carrier is divided into a number of time slots and each user is assigned a different time slot so that until the ongoing call is finished, no other subscriber can have access to this. GSM uses both Time Division Multiple Access (TDMA) and Frequency Division Multiple Access (FDMA) for user and cell separation. TDMA provides multiuser access by chopping up the channel into different time slices and FDMA provides multiuser access by separating the used frequencies.

2.      Security

More security is provided in CDMA technology as compared with the GSM technology as encryption is inbuilt in the CDMA. A unique code is provided to every user and all the conversation between two users are encoded ensuring a greater level of security for CDMA users. The signal cannot be detected easily in CDMA as compared to the signals of GSM, which are concentrated in the narrow bandwidth. Therefore, the CDMA phone calls are more secure than the GSM calls. In terms of encryption the GSM technology has to be upgraded so as to make it operate more securely.

3.      Spectrum Frequencies

The CDMA network operates in the frequency spectrum of CDMA 850 MHz and 1900 MHz while the GSM network operates in the frequency spectrum of GSM 850 MHz and 1900 MHz.

4.      Global Reach

GSM is in use over 80% of the world’s mobile networks in over 210 countries as compared to CDMA. CDMA is almost exclusively used in United States and some parts of Canada and Japan. As the European Union permissions GSM use, so CDMA is not supported in Europe. In North America, especially in rural areas, more coverage is offered by CDMA as compared to GSM. As GSM is an international standard, so it’s better to use GSM in international roaming. GSM is in use by 76% of users as compared to CDMA which is in use by 24% users.

5.      Data Transfer Rate

CDMA has faster data rate as compared to GSM as EVDO data transfer technology is used in CDMA which offers a maximum download speed of 2 mbps.  EVDO ready mobile phones are required to use this technology. GSM uses EDGE data transfer technology that has a maximum download speed of 384 kbps which is slower as compared to CDMA. For browsing the web, to watch videos and to download music, CDMA is better choice as compared to GSM. So CDMA is known to cover more area with fewer towers.

6.      Radiation Exposure

GSM phones emit continuous wave pulses, so there is a large need to reduce the exposures to electromagnetic fields focused on cell phones with “continuous wave pulses”. On the other hand CDMA cell phones do not produce these pulses. GSM phones emit about 28 times more radiation on average as compared to CDMA phones. Moreover, GSM phones are more biologically reactive as compared to CDMA.

The birth of mobiles created gateways for many networking companies to set their foot in the field of mobile technology. Today there are two most appreciated mobile network technology that are ruling the market. All the mobile network service providers nowadays are heavily depending on either GSM or CDMA. Both these technologies are accelerating the demand of mobiles.

Generally, speaking GSM and CDMA are both used for mobile communication process, but still there are some differences between them that allow them to remain intact with their individuality. Companies like T-mobile, Verizon and many other are today using any one of the technology. Talking about GSM, the entire concept came into existence in the year 1987 and since then they are developing and nurturing the entire process of wireless technology. On the other hand the CDMA is a baby of U.S based organization that dominates in the entire Northern region of U.S and Asia, is slowly making its way in the other parts of the world as well.
The architecture of both the network is supported by arguments from their voters, each trying to prove the speciality and efficiency of the network, however, the argument is still on. Explaining the facts and difference between both the networks to the end user will certainly play a different impact. The differences are stated considering the following factors;
Network Coverage: For the user, it is important to check the type of network available in the region where the mobile will be used. This will guide them with the details about the competitors and their services. It might also happen that either of the network is available, which certainly leaves them with no option.
Speed for Data Transition: As nowadays mobiles are much more than just a calling device, their multitasking has surely made them like a little genie, which are competent of handling more than what can be said. To perform these tasks the mobile seeks for a network that can empower its abilities and can make them perform at a higher speed.
Both CDMA and GSM are 3G technologies, but still they have different set of performance factor. The GSM technology is said to accelerate performance by 384 kbps, along with EDGE technology, however, in the real world the speed lies around 275 to 380 kbps.
Power of SIM Cards: Generally the mobile phone comes to life when the SIM card is inserted. GSM phone duly support this technology. Here the SIM is actually already connected with the network, so when one inserts this card in their mobile, automatically after switching on the mobile get on to the same network, on the other hand the neither CDMA phones are not card based phones. Here the sets are proprietary based, therefore in case of switching phone; the carrier needs to deactivate the old phone and then activate the new phone, and this discards the early sets.
National and International Roaming: GSM have a wider coverage as it has contracts with other GSM carriers. This often are very good for the users as the roaming charges in such a case are waved off and user enjoy full service with no extra cost. On the other hand the CDMA user does not enjoy the wider coverage. Mainly the rural areas are left untouched. Apart from that they also have to shell extra money as for enjoying services while they are on move to locations beyond their prime location.
When it comes to international roaming, the GSM cards allow the user to make calls to any part of the world due to their dominance in the market. On the other hand if the user is travelling to international locations then to save money they can use a local SIM and can enjoy calling other places at fairly reasonable rate. However, the CDMA phones are not of much help in case of international roaming, because they are not card based phone. Though there are many countries that have CDMA networks but then the user need to discuss things with their network provider.
These differences do state that the numbers of users of GSM are fairly high in comparison with the CDMA. Once CDMA incorporates some flexibility in their system there are great opportunities for it to attract more users, as things will be more clear and transparent.