CDMA and GSM
CDMA: Code Division Multiple Access is a technology developed by Qualcomm in the United States, and it is currently the dominant network standard in North America.
GSM: Global System for Mobile communications was invented in 1987 by the GSM Association, an international organization dedicated to developing this standard worldwide.
Below are the different parameters discussed in detail of CDMA vs. GSM
1.1 Coverage of CDMA vs. GSM
CDMA
- It is mostly used in America and some parts of Asia. It is currently making progress in other parts of the world, but the coverage is still limited compared to the GSM technology.
- CDMA generally offers a better coverage than GSM in some rural areas because it was deployed earlier.
- Its network reaches over 270 million users worldwide.
GSM
- GSM being an international standard, it is better suited for international roaming, provided you own a quad-band cell phone (850/900/1800/1900 MHz).
- The GSM network is also well established in North America, but not as much as the CDMA network yet. Its network reaches over a billion users worldwide.
Note: CDMA is prominent in North America, but GSM reaches a lot more users worldwide (about 1 billion vs 270 million).
1.2 Data Transfer
CDMA
- The best data transfer technology it has to offer is the EVDO technology, allowing for a maximum download speed of about 2mb/s (about 700kbps in practice), which is similar to what a DSL line has to offer.
GSM
- GSM allows for a maximum download speed of 384kbps (around 140kbps in practice). More technologies are being developed on top of EDGE such as HSDPA to boost the transfer rate to over 384kbps in practice. This technology requires an EDGE-ready cell phone.
Note: CDMA offers faster data download and would therefore be the favoured choice for data transfer. GSM is catching up fast however, but its EDGE technology is subject to interference’s.
1.3 Phone Identification (SIM card)
CDMA
- Your account information is programmed into your cellular phone. If you want to change your phone, you have to contact your carrier and have them reprogram your new phone.
- You will also need to re-enter your contact list and calendar information into your new phone. If you have a lot of contacts, your carrier might be able to help you perform this task.
- Some CDMA 2000 cell phones support R-UIM cards (Removable User Identity Module) which are used to store account information and contact lists, but these are not very common in North America yet.
GSM
- Your account information along with your contact list and other personal data are stored on a SIM card (Subscriber Identity Module).
- It is a small chip you can freely remove from your phone. When you get a new mobile device, you can simply insert your SIM card into it and it will work with your current account information and contact list.
- If you travel to another country, it might even be possible to purchase a prepaid SIM card which you can use to avoid roaming fees.
Note: GSM is a clear winner here. The SIM card technology offers many advantages if you plan to travel or switch phone often. CDMA phones are slowly catching up with R-UIM cards, but cell phones that make use of this technology as still rare.
Which technology is the best?
It depends upon the requirement of particular user-
1. Is international roaming important to user?
- If user travel a lot to foreign countries, user might want to opt for a GSM phone for a better coverage.
2. If user transfer a lot of data using the phone?
- If user intend to use the phone for mobile web browsing, watching television or downloading MP3s, user might be better off with a CDMA phone.
- Currently, it offers the best data transfer speed with its EVDO technology and is the clear winner for now.
3. if user plan to change phone often?
- If user do, a GSM phone is best for you since you can swap the SIM card to a new device without having to re-enter your personal data.
Table 1.1 ( comparison between CDMA vs GSM)
Parameter CDMA GSM
| Stands for |
Code Division Multiple Access |
Global System for Mobile communication |
| Storae Type |
Internal Memory |
SIM (subscriber identity module) Card |
| Global market share |
25% |
75% |
| Domince |
Dominant standard in the U.S. |
Dominant standard worldwide except the U.S. |
| Data transfr |
EVDO/3G/4G/LTE |
GPRS/E/3G/4G/LTE |
| NetwoR-k |
There is one physical channel and a special code for every device in the coverage network. Using this code, the signal of the device is multiplexed, and the same physical channel is used to send the signal. |
Every cell has a corresponding network tower, which serves the mobile phones in that cellular area. |
| Interna-tional roaming |
Less Accessible |
Most Accessible |
| Freque-ncy
Band |
Single (850 MHz) |
Multiple (850/900/1800/1900 MHz) |
| Networ-k service |
Handset specific |
SIM specific. User has option to select handset of his choice. |