Sparse Channel Estimation Using Orthogonal Matching Pursuit (OMP) for MIMO-OFDM System

The OFDM is a multicarrier technique that is well-known for its capability to cope with highly time-variant wireless channel. When combined with a multiple-input multiple-output (MIMO) technique, MIMO-OFDM system can offer reliable high data rate transmission over broadband wireless channels. In such system, the availability of channel state information (CSI) is critical issue that will determine overall performance of the system. CSI is commonly acquired through pilot-aided methods due to its simplicity and reliability. By taking advantage of the channel sparseness, compressive sensing (CS) can be utilized for channel estimation with much fewer pilot symbols. In this paper, orthogonal matching pursuit (OMP) is employed to reconstruct channel impulse response. We evaluate the performance in terms of NMSE and BER. The simulation results shown that OMP algorithm outperforms LS in channel estimation with more efficient number of pilots. The BER performance also gives only slight difference compared to the system with known channel coefficient.