Abstract: A robust zero-forcing receiver in the Multiple Input Multiple Output (MIMO) channel with a channel estimation error is presented. By considering the statistics of channel estimation errors, the coefficient of zero-forcing filter is modified with the estimated channel information. The presented receiver is more robust than the traditional ZF receiver in the presence of inaccurate channel information in the receiver. Simulation results show that the BER (bit error rate) is improved and that the error floor is lower than that of the traditional receiver with the same estimation error. In the uncoded 4×4MIMO system with QPSK modulation and if the channel estimation error coefficient equals 0.05, the BER of the traditional ZF receiver is 5×10-3 and that of the presented receiver is 1.8×10^-3 at a high SNR. It is also shown that the system with QPSK modulation can work effectively when the estimated channel error is smaller than three times the real channel error.

Key words: multiple input multiple output, estimation, zero forcing receiver, channel error, bit error rate