In this paper, we propose a learning-based detection framework for uplink massive multiple-input and multiple-output (MIMO) systems with one-bit analog-to-digital converters. The learning-based detection only requires counting the occurrences of the quantized outputs of -1 and +1 for estimating a likelihood probability at each antenna. Accordingly, the key advantage of this approach is to perform maximum likelihood detection without explicit channel estimation which has been one of the primary challenges of one-bit quantized systems. The learning in the high signal-to-noise ratio (SNR) regime, however, needs excessive training to estimate the extremely small likelihood probabilities. To address this drawback, we propose a dither-and-learning technique to estimate likelihood functions from dithered signals. First, we add a dithering signal to artificially decrease the SNR and then infer the likelihood function from the quantized dithered signals by using an SNR estimate derived from a deep neural network-based offline estimator. We extend our technique by developing an adaptive dither-and-learning method that updates the dithering power according the patterns observed in the quantized dithered signals. The proposed framework is also applied to state-of-the-art channel-coded MIMO systems by computing a bit-wise and user-wise log-likelihood ratio from the refined likelihood probabilities. Simulation results validate the detection performance of the proposed methods in both uncoded and coded systems.
翻译:本文提出了一种学习型检测框架,用于带一位模拟-数字转换器的上行大规模多输入多输出(MIMO)系统的检测。学习型检测只需要计算-1和+1量化输出的出现次数来估计每个天线的似然概率。因此,该方法的主要优势在于,在不需要明确通道估计的情况下执行最大似然检测,这一点一直是一个一位量化系统的主要挑战之一。然而,在高信噪比(SNR)下的学习需要大量训练来估计极小的似然概率。为了解决这个缺点,我们提出了一种扰动-学习技术,通过添加扰动信号来人为降低信噪比,然后通过使用一个基于深度神经网络的离线估计器得到的SNR估计值从量化的扰动信号中推断似然函数。我们通过开发一种自适应扰动学习方法来扩展我们的技术,该方法根据观察到的量化的扰动信号中的模式更新扰动功率。该提出的框架也应用于最先进的编码MIMO系统中,通过从完善的似然概率计算比特级别和用户级别的对数似然比。仿真结果验证了所提出方法在无编码和编码系统中的检测性能。