Frequency-Channelized Mismatch-Shaped Quadrature Data Converters for Carrier Aggregation in MU-MIMO LTE-A
Frequency-Channelized Mismatch-Shaped Quadrature Data Converters for Carrier Aggregation in MU-MIMO LTE-A
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DOI：
10.1109/tcsi.2016.2603442
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发表时间：
2017
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影响因子：
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通讯作者：
S. Kundu;Subhanshu Gupta;D. Allstot;J. Paramesh
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文献类型：
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作者：
S. Kundu;Subhanshu Gupta;D. Allstot;J. Paramesh
新兴的无线标准通过选择连续或非连续信道的组合来聚合信息，从而实现更宽的传输带宽，从而实现更高的数据速率。频率交错模数转换 (FI-ADC) 对于载波聚合接收器来说是一项颇具吸引力的新兴技术，因为它提供了一种有效的方法来动态改变接收器带宽，以应对多种可能的信道组合。与时间交织的同类产品相比，FI-ADC 并行通道中采样器的规格显着放宽，从而降低了接收器的总体功耗。这项工作将 FI-ADC 概念扩展到正交频率交错过采样数据转换器 (QFI-ADC)，以实现更高的聚合数据速率。此前，数模转换器 (DAC) 和其他通道间不匹配限制了 QFI-ADC 的性能。在本文中，我们提出了一种低复杂度的元素旋转算法 (ERA) 来减轻 DAC 不匹配的情况。 ERA 是使用严格的数学程序从相应的失配传递函数合成的，该数学程序被证明通常适用于低通、高通、带通和正交 ERA。仿真证实，所产生的低复杂性正交 ERA 在性能和硬件复杂性方面均优于先前提出的方法。额外的增益校准技术可减轻由于正交 DAC 元件之间的增益和时序不匹配而导致的图像折叠，从而产生更高的 SNDR。
Emerging wireless standards aggregate information by selecting combinations of contiguous or non-contiguous channels, thereby enabling wider transmission bandwidths, and hence, higher data rates. Frequency-interleaved analog-to-digital conversion (FI-ADC) is an attractive emerging technique for carrier aggregation receivers because it facilitates an efficient way to dynamically vary the receiver bandwidth in order to address the many possible channel combinations. Compared to their time-interleaved counterparts, the specifications of the samplers in the parallel channels in FI-ADCs are significantly relaxed, thereby resulting in lower overall power consumption in the receiver. This work extends the FI-ADC concept to the quadrature frequency-interleaved oversampled data converter (QFI-ADC) to achieve greater aggregate data rates. Previously, digital-to-analog converter (DAC) and other inter-channel mismatches have limited the performance of QFI-ADCs. In this paper, we propose a low-complexity element rotation algorithm (ERA) to mitigate DAC mismatches. The ERA is synthesized from the corresponding mismatch transfer function using a rigorous mathematical procedure which is shown to be applicable generally to low-pass, high-pass, band-pass and quadrature ERAs. Simulations confirm that the resulting low-complexity quadrature ERAs have advantages over previously proposed approaches in both performance and hardware complexity. An additional gain calibration technique alleviates image folding due to gain and timing mismatches between the quadrature DAC elements, which yields higher SNDR.