Channel Estimation on MIMO-OFDM System

Wireless communication systems face several problems. This includes frequency fading, multipath fading, Inter Carrier Interference (ICI), Inter Symbol Interference (ISI) etc. Requirement of larger transmit power at high rate, spectral efficiency and low bit rate capacity are other disadvantages. OFDM is an effective technique for high data rate wireless communication in multipath channels and fading environments at reasonable frequency in wireless channels. Because of the nature of its high speed data transmission and effectiveness in combating the frequency selective fading channel, it is adopted in recent days by many systems. Recently, multiple input multiple output (MIMO) channels have been introduced to achieve high data speed requisite by the next-generation communication systems. The channel characteristics can be estimated by using a preamble or pilot symbols known to both transmitter and receiver, which employ various interpolation techniques to estimate the channel response of the subcarriers between pilot tones. Generally, data signal as well as training signal, or both, can be used for channel estimation. This method can greatly reduce interference because the multiple antennas use the same frequency to transmit data in the OFDM transmission system, which can be applied to wireless mobile MIMO-OFDM communication system with double selective fading.