The advantages of code division multiple access technology, or CDMA, are its ability to cover more area with fewer towers and deliver fewer dropped calls, faster speeds and overall better quality, while the advantages of global system for mobile technology, or GSM, are the possibility to switch phones easily by transferring the SIM card and better competency for international roaming. CDMA is the dominant standard in the United States, while GSM is the dominant standard everywhere else in the world.
CDMA does not have a limit on the number of users, and more users can be added easily. It also has better signal quality. The code sent cannot be deciphered by hackers. It is compatible with other cellular technologies; this allows for nationwide roaming. Multipath fading is significantly reduced because of large signal bandwidth, and the procedure of soft handoff reduces the chance of signal breakup as a handset passes from one cell to another.
GSM allows the radio spectrum to be shared by multiple users accessing similar frequency band without causing any disturbance. It is used all over the world, with more than 450 million users. SIM cards provide secure data encryption to give GSM advantages in mobile commerce. GSM is the standard in more than 200 countries, so travelers can use GSM phones in these countries with the use of a local SIM card. This cannot be achieved with a CDMA phone, as the network used is handset specific.