IEEE Transactions on Vehicular Technology, vol. 57, no. 5, pp. 2991-3005, Sept. 2008.
We consider the system that multiple transmitters send signals to a receiver in the asynchronous MIMO-OFDM mode. A receiver structure that can perform joint synchronization and space-time equalization for the asynchronous MIMO-OFDM systems is proposed. We first introduce a novel space-time equalization algorithm based on the channel state information. This algorithm aims to null the cochannel interference and combat asynchronism as well as minimize a lower bound to the symbol error rate in the asynchronous MIMO-OFDM system. In the second part of the paper, we propose a trainingbased minimizing mean square error (MMSE) algorithm to jointly obtain the frequency offsets and the equalization delays. We compensate for the effects of frequency offsets and propagation delays with these estimated parameters, and then use the proposed direct training-based equalizer design algorithm to obtain the equalizer coefficients. The simulation section illustrates the desirable bit error rate (BER) performance of our proposed algorithms.
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