Performance analysis of Various Modulation Techniques Used in OFDM with the Impact of FFT for 4G Network.

Abstract

We are now in an era of technology. With the demand of people the communication system is also developed along technology. At first there was only Telegraph. Then after a long time and evaluation some reliable system arrived at 1982 with AMPS and at 1983 TACS. But the systems were analog. Then GSM (Global System for Mobile Communication) has arrived which was known as the 2nd generation mobile communication. FDM (Frequency Division Multiplex) and TDM (Time Division Multiplexing) was used in this system. But it has some limitations too. It has low data rate. But people need higher mobile data rate and better services. In order to solve the problem, WCDMA (Wideband Code Division Multiple Access) came with 3rdgeneration communication system. It has a better data rate than GSM. After that 4th generation mobile communication system along with OFDMA is released. This has multicarrier and FDM also. But we need more efficient system that could make the other systems integrated with itself making some long time useful features. That’s why we need to make the 4th generation network system more upgraded. That system would like to be the most advanced system which would have large bandwidth, high data rate and the exciting features that the previous systems couldn’t provide. To establish that system we can use OFDM (Orthogonal Frequency Division Multiplex). We also have to integrate the entire previous system into one platform. OFDM (orthogonal frequency division multiplexing) transmission scheme is used to overcome multipath-fading environment with low complexity.