2G, 3G, 4G are the generation wise segregations in terms of Voice data experience for a user from low data throughout on 2G to higher data throughputs in 4G, 2G is the 2nd genration telecommunications which uses TDMA & FDMA where as 3G used WCDMA technologies but 4G uses more advance technology like SCFDMA for uplink & OFDMA for downlink. 2G was more voice centric & 4G is more data centric