Channel Estimation Methods Based On Training Sequence For MIMO-OFDM System

Orthogonal frequency division multiplexing (OFDM) offers high-speed transmission in wireless environment. It converts a frequency-selective channel into a parallel collection of frequency flat sub-channels, thereby eliminates the effect caused by the frequency-selection fading. OFDM also suppresses multi-path effect and ISI (Inter-Symbol Interference), and has high level of spectrum efficiency. In a wireless communication system with multiple antennas in both transmitter and receiver, if there's enough distance between every antenna, then each pair of transmitting antenna and receiving antenna will have separate multi-path fading performance. That means the channel between each antenna pair can be independent. Therefore, all the sub-channels, although having same frequency, same time, same channel codes, will be orthogonal from each other. This characteristic of wireless channel is used in MIMO technology, which makes full use of space resources and doubles channel capacity without power increasing. MIMO can also offer great reliability and low BER performance. So OFDM could be effectively combined with MIMO, by using antenna arrays at the transmitter and receiver, to increase the diversity gain and to enhance the system capacity.In this paper, we give detail information about the multi-path fading...