A low complexity time domain equalization scheme for orthogonal frequency division multiple access (OFDMA) systems at downlink is presented in this paper. We consider the comb-type sub-carriers assignment for a resource block. According to the Orthogonality theorem, the dedicated resource block assigned to the user is demultiplexed by multiplying the associated coefficient This approach is less computational complexity compared to fast Fourier transform(FFT) scheme. The inter-symbol interference(ISI) resulted from multipath fading channel is compensated in the time domain. To avoid complex high-order matrix inversion, pair-wise sub-carriers allocation and equalization are suggested. Computer simulations and complexity comparisons are conducted to evaluate the performance of the proposed time domain equalization and detection schemes. The proposed schemes are shown to be feasible and remarkable reduction in computational complexity is disclosed.
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