Mobile wireless communications systems are frequently classified by generation. First generation wireless denotes voice-only analog cellular systems. Second generation wireless systems works on digital transmission technologies to meet with the capacity demands of growing voice services. The coming third generation differs from previous systems more in the ability to integrate voice and data applications than in progressive differences in transmission technology. A number of high-speed digital wireless technologies currently exist like Bluetooth and 802.11 etc. works for short distances. So, cellular providers seek to increase speed on their long-range wireless networks that called Fourth-Generation (4G) wireless system.