Investigation of Channel Estimation Techniques using OFDM with BPSK QPSK and QAM Modulations

In the past years, the growth of mobile communication networks has been depending on the throughput and data rate, these parameters are affected by different kinds of noise such as white noise, Gaussian noise, and ISI (Inter Symbol Interference) which are added in the communication channel. Channel estimation is the major contest to the wide use of 4G cellular networks with OFDM to reduce all kinds of noises. There is rigorous work has been going on to develop reliable, accurate, and efficient channel estimation techniques for different wireless cellular standards. This paper describes the performance of different channel estimation techniques like the Interpolation techniques of Liner, Cubic Spline, and DFT by varying modulation techniques like QPSK, BPSK, and QAM. To identify efficient channel estimation techniques, it is necessary to investigate and compare the working of these systems in different communication environments. Due to the nature of modulating signal in both amplitude and phase, the QAM gives good performance and due to performing of estimation on limited samples by suppressing estimation values to zero for remaining the DFT estimator gives an accurate performance. These methods are compared concerning Signal to Noise Ratio (SNR) vs Bit Error Rate (BER).