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This paper considers a massive single-input singleoutput (SIMO) system with 1-bit analog-to-digital converters (ADCs) at the base station (BS). In this context, the stochastic resonance phenomenon can be exploited together with the massive number of antennas to enable the symbol detection. In this regard, we investigate the statistics of the estimated symbols when maximum ratio combining (MRC) is adopted at the BS. In addition, assuming 16 quadrature amplitude modulation (16-QAM), we propose three different symbol detectors that are designed based on the mean and variance of the MRC outputs. Through numerical evaluations, we show that the proposed symbol detectors can significantly enhance the symbol error rate performance of massive SIMO systems with 1-bit ADCs.

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In this paper, we investigate a transmitter and receiver design for a single-user massive SIMO (single-input multiple-output) system with 1-bit analog-to-digital converters (ADCs) at the base station (BS), where the user adopts higher-order modulation, e.g., 16-quadrature amplitude modulation (16-QAM), for the data transmission. For the channel estimation and the signal detection, linear least-squares (LS) estimation and maximum ratio combining (MRC) are respectively employed. In this context, we first introduce closedform formulas for the mean of the estimated symbols and for the correlation matrix between their real and imaginary parts considering the effect of 1-bit quantization. The study of the distribution of the estimated symbols indicates that, in presence of 1-bit ADCs, the conventional 16-QAM detector and the typical square 16-QAM modulation are not adequate. In light of this, we propose three novel symbol detectors and re-design the 16-QAM modulation in order to improve the symbol error rate (SER). Furthermore, the upper bound on the SER is analyzed based on the pair-wise error probability and the boundary equation between two regions is also studied. Through numerical results, the proposed framework, i.e., the symbol detector and the transmit constellation design, shows a significant enhancement in the SER performance against the conventional detector and the typical square 16-QAM modulation.INDEX TERMS Massive MIMO, 1-bit ADCs, data detection, upper bound on the SER, transmit constellation design.