AN EFFICIENT PILOT CARRIER CHANNEL ESTIMATION USING GENETIC ALGORITHM IN 4G MIMO-OFDM SYSTEM
MIMO-OFDM (multiple input multiple output-orthogonal frequency division multiplexing) is an excellent technique used in modern wireless communication systems. It has excellent quality of high speed data/voice transmission with high spectral efficiency. The Least Square (LS) and Minimum Mean Square Error (MMSE) channel estimation are the most common methods presented by several researchers. Discrete Fourier Transform (DFT)-based channel estimation is introduced to minimize the receiver noise
... rference which cannot be possible in the LS and MMSE techniques. Also, Genetic Algorithm-based optimized 4G channel estimation is proposed in this paper to identify the best channel matrix from the existing LS, MMSE and DFT estimation algorithms. The simulation results clearly show that the performance of optimized GA-based DFT channel estimation is better than the LS and MMSE estimation. INTRODUCTION Orthogonal Frequency Division Multiplexing (OFDM) technique can be used as an excellent multi-carrier modulation technique to transmit high speed multimedia information. The OFDM technique carries high data rate information by multiplexing numerous parallel low rate data streams with orthogonal sub-carriers. This technique has high spectral efficiency and also less inters symbol interference (ISI). If this technique is combined with Multi Input Multi Output (MIMO), a major improvement in the quality of service and channel capacity will be obtained. In order to retrieve the data at receiver, the channel state information (CSI) is very much essential. The channel estimation technique is mainly used to identify the CSI at the receiver. This improves the accuracy and the reliability of the wireless link. In the training-based channel estimation, pilots are inserted into the particular position of each sub-carrier of OFDM symbols and transmitted. This estimation provides better resistance to fast fading and time varying channels  The popular Least Square (LS) channel estimation and Minimum Mean Square Error (MMSE) estimation techniques cannot minimize the noise levels at the receiver side. Hence, DFT channel estimation is introduced with LS and MMSE channel estimations to minimise the noise. Efficient genetic algorithm based channel estimation is executed in this work by proper mutation of LS and MMSE and DFT channels. This article is planned as follows: 4G Channel estimation in MIMO-OFDM system model is presented in the next section followed by the DFT channel estimation model. The next section deals with genetic algorithm-based optimization. Simulation and results are discussed in the next section followed by the conclusion.