High hardware cost and high power consumption of massive multiple-input and multiple output (MIMO) are two challenges for the future wireless communications including beyond fifth generation (B5G) and sixth generation (6G). Adopting the low-resolution analog-to-digital converter (ADC) is viewed as a promising solution. Additionally, the direction of arrival (DOA) estimation is an indispensable technology for beam alignment and tracking in massive MIMO systems. Thus, in this paper, the performance of DOA estimation with mixed-ADC structure is firstly investigated. The Cramer-Rao lower bound (CRLB) for this architecture is derived based on the additive quantization noise model. Eventually, a performance loss factor and the associated energy efficiency factor is defined for analysis in detail. Simulation results show that the mixed-ADC architecture can strike a good balance among performance loss, circuit cost and energy efficiency. More importantly, just a few bits (up to 4 bits) of low-resolution ADCs can achieve a satisfactory performance for DOA measurement.
翻译:采用低分辨率模拟数字转换器(ADC)被认为是一个大有希望的解决办法,此外,抵达方向估算是大型MIMO系统对光束调整和跟踪的一个不可或缺的技术,因此,本文件首先调查了DOA对混合ADC结构的估算绩效。这一结构的Cramer-Rao较低约束值(CRLB)是根据添加式量化噪声模型得出的。最后,确定了一个性能损失系数和相关的能效系数,以便进行详细分析。模拟结果表明,混合ADC结构可以在大型MIMO系统中的性能损失、电路成本和能效之间取得良好的平衡。更重要的是,只有一小部分(多达4位)低分辨率ADC的性能能够为DA的测量取得令人满意的绩效。