UMTS

Which Are GSM? In the US, Verizon, US Cellular, and the old Sprint network (now owned by T-Mobile) used CDMA. AT&T and T- Mobile used GSM. Most of the rest of the world used GSM.

Comparison table GenerationTechnologySignal quality/coverage area3GW-CDMASmaller cells and lower indoors coverage on 2100 MHz; equivalent coverage indoors and superior range to GSM on 850/900 MHz.4GOFDMASmaller cells and lower coverage on the S band.5GOFDMADense cells on millimeter waves.Comparison of mobile phone standards – Wikipedia en.wikipedia.org › wiki › Comparison_of_mobile_phone_standards

GSM/WCDMA (WCDMA preferred) – The GSM phone can use both 2G and 3G data communication and when signal strength is low 3G is favored more. GSM only – The GSM phone use only 2G data communication . When the 2G signal is too low you get nothing. WCDMA only – The GSM phone use only 3G data communication.

GSM belongs to the second-generation (2G) of mobile networks, UMTS belongs to the third-generation (3G) of mobile networks, and LTE belongs to the fourth-generation (4G) of mobile networks . Multiple cellular technologies enable 2G and 3G, but LTE is the only technology that enables 4G.13 Eyl 2019

GSM supports both cellular and data, whereas LTE is synonymous with high-speed wireless broadband technology that supports only data . This is why most of the new cell phones use LTE for high-speed internet access and rely on GSM for voice calls.