Multipath Delay Estimation with Interference Cancellation in MIMO-OFDM System

In this paper we propose a multipath delay estimation scheme for MIMO-OFDM system with the code division preamble. The algorithm is composed of three steps: the delays of L₁ stronger paths are firstly estimated by coarse multipath delay estimation module. Then the channel coefficients of L₁ paths are estimated and fed back to interference reconstruction module, by which the interference from other antennas will be recovered. After interference cancellation, fine multipath delay estimation module is used to get the delays of L paths and accurate estimation of delays could be taken advantage by channel estimation module. It is verified by simulation that the proposed algorithm can correctly estimate all paths for 4 antennas once SNR is higher than 6 dB. As antenna number is increased to 16, the correct estimation probability of former 4 paths is still about 90% when SNR is higher than 3 dB. So the proposed multipath delay estimation scheme with interference cancellation can efficiently improve the accuracy of multipath delay estimation in MIMO-OFDM system.