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  • 15:05, 18 November 2019 diff hist +152 Template:Comparison of mobile Internet standardsCorrects UMTS, WIFI and LTE. UMTS uses CDMA on downlink but HSPA uses CDMA and TDMA. There are only 15 different spreading factor in HSPA downlink, unlike WCDMA where SF can differ from 4 to 256, thus TDMA has to be deployed. LTE also uses TDMA on downlink for similar reason, where every UE has to use a minimium of 180KHz, which is too wide for a cell tower only has 10-20MHz. WiFi is half duplex and CSMA based.