A Low Complexity Receiver for OFDMA Systems at Downlink

This paper presents a low complexity receiver for downlink orthogonal frequency division multiple access (OFDMA) systems. We consider the comb-type subcarriers assignment for a resource block. Based on this arrangement, a resource block could be demultiplexed at the user equipment without performing fast Fourier transform(FFT) on one OFDMA symbol. The inter-symbol interference(ISI) resulted from multipath fading channel is also studied in this paper and a time domain channel equalization scheme is proposed. For practical implementation, pairwise subcarriers allocation and equalization are presented. Computer simulations and complexity comparisons are conducted to evaluate the performance of the proposed pairwise resource allocation and channel equalization schemes. It is shown in this paper that the proposed schemes are feasible and superior for practical downlink OFDMA receiver implementation.