Performance Evaluation of Channel Estimation Methods in OFDM Systems

In the communication sector, a large amount of data needs to be transmitted very quickly with an increasing user demand. To accommodate these demands, single carrier systems leave their place to multiple carrier systems. The transmission of large amounts of data at high speed requires high-quality radio access over multi-way damped channels. The amplitudes of the signals reaching the receiver at different times and paths are caused by fluctuations in the signal strength, this is called damping effect. The received signal is weaker than the transmitted signal due to the average transmission loss and damping. The adverse effects such as the damping effect on the communication channel greatly affect the performance of the wireless communication and prevent to reach high transmission speeds. In addition to multipath demodulation, multipath propagation also extends the time required for the transmitted signal to reach the receiver. In wireless communication systems, the best way to mitigate the damping effect on the channel is to take advantage of diversification techniques. OFDM, one of the multi-carrier systems, provides efficient channel capacity enhancement. In this study, the performances of least squares (LS) and minimum mean square error (MMSE) estimation methods, which are channel estimation methods, required to remove the interchannel interference in the OFDM technique are investigated by computer simulations. In interchannel interference in the OFDM technique is analyzed with LS and MMS estimation methods and results are compared with respect to Signal to Noise Ratio aspect. The results are promising.