Subcarrier-Based Block-Iterative GDFE (BI-GDFE) Receivers for MIMO Interleaved FDMA

Interleaved frequency division multiple access (IFDMA), which has been adopted as the uplink air-interface for the third generation long term evolution (3G-LTE), outperforms its competing rival OFDM/OFDMA for its low peak-to-average power ratio (PAPR). To achieve future high-speed transmission rate, spatial multiplexed multiple-input multiple-output (MIMO) system is incorporated into IFDMA. Although no multiple access interference (MAI) exists, the system suffers heavily from both inter-symbol interference (ISI) and multi-stream interference (MSI). Block-iterative decision feedback equalizer (BI-GDFE) can be applied to mitigate the interference effectively. In this paper, a subcarrier-based processing technique is proposed to achieve same performance with significant complexity reduction over conventional BI-GDFE equalization approach in MIMO-IFDMA system. To achieve even further gain in computational efficiency, a suboptimal BI-GDFE equalizer is also designed with only slight performance degradation. Computer simulations are presented to illustrate the BER performances of MIMO-IFDMA system with the proposed equalizers.