MPDQ-based high-order QAM detection scheme for massive MIMO with low-precision quantization

High-order quadrature amplitude modulation (QAM) signals typically requires high-precision ADC at the receiver for reliable detection. However, in massive multiple-input multiple-output (MIMO) systems, the power consumption and hardware cost can be unaffordable due to the high complexity of conventional signal detectors and the associated high-precision ADC required by each antenna. To solve this problem, this paper proposes a low-complex iterative detector based on message passing de-quantization (MPDQ), which can detect high-order QAM data with low-precision quantization. Compared with the conventional signal detectors, the proposed scheme substantially reduces the cost and complexity by matrix-vector multiplication. Simulation results demonstrate that the proposed algorithm with 7 bits quantization could achieve better bit error rate (BER) performance than MMSE with full precision system, thus saving 3 bits or more by comparison.