Difference between GSM and CDMA

GSM stands for Global System for Mobile communication, while CDMA stands for Code Division Multiple Access GSM uses FDMA (Frequency division multiple access) and TDMA (Time division multiple access). GSM supports transmitting data and voice both at once, but CDMA does have not this feature. The main distinction between GSM and CDMA is that in GSM, the customer information is put on a SIM card which can be moved to a new mobile phone. Whereas only mobile phones from a set of whitelisted companies can be used with a CDMA network. 

The differences between GSM and CDMA are as follows:

Serial No.	GSM	CDMA
1. Full form global	Global System for Mobile communication.	Code Division Multiple Access.
2. Technology used	FDMA(Frequency Division Multiple Access) and TDMA (Time Division Multiple Access).	CDMA(Code Division Multiple Access).
3. Availability	GSM is globally widely used and available.	CDMA is available in fewer countries and carriers.
4. Data speed rate	42Mbps in HSPA (3G).	3.6Mbps in CDMA.
5.Features	GSM supports transmitting data and voice both at once.	CDMA does not support this feature.
6. Customer Information	Stored in a SIM card.	Stored in a headset or phone.
7. Encryption	GSM does not provide built-in encryption is available.	CDMA provides built-in encryption.
8. Secure	GSM offers less secure communication.	CDMS offers secure communication.
9. Roaming	GSM enables worldwide roaming.	CDMA enables limited roaming.
10. Signal Detection	GSM signals can be detected since they are focused in a narrow bandwidth.	CDMA transmissions are difficult to detect.
11. SIM Card	There is always a requirement of SIM card for a GSM device to function.	There are no such requirements for CDMA phones.
12. Flexibility	When a SIM on a phone stops working, we can use another SIM rather than purchasing a new phone.	When a CDMA on a phone ceases operating, we must purchase a new phone.
13. Type of Spectrum	GSM technology operates on a wedge spectrum known as carrier.	CDMA technology is based on spread spectrum technology.
14. MIMO (Multiple Input Multiple Output) method	GSM follows 2*2 MIMO.	LTE adheres to 8*8, 4*4 MIMO and also supports cooperative MIMO and multi-user MIMO.