Channel estimation in MIMO-OFDM spatial multiplexing using Least Square method

In this paper, channel estimation for Spatial Multiplexing (SM) is investigated for MIMO-OFDM system. Due to the channel characteristic of the transmission system is always changed by the time and its importance in wireless transmission to reconstruct the transmitted signals, the channel needs to be known as well as possible. Pilot symbols are used to gather knowledge about the channel and try to estimate it. The channel estimation based on the pilot symbol is called pilot aided channel estimation. In this research, Least Square (LS) method was chosen for initial channel estimation. By using applicable proposed system design, channel state information is estimated through the use of channel information before in subcarriers with no pilot symbols. Zero forcing (ZF) algorithm is used to detect and separate the received signal. The result shows that channel estimation would be better by increasing SNR. Normalized Mean Square Error (NMSE) value of the channel reached 5×10^-5 for SNR 25 dB. The value of BER reached 3×10^-4 for SNR 25 dB. The estimated channel capacity has the values that closed to the known channel capacity.