6.6 Full-Duplex Receiver with Wideband Multi-Domain FIR Cancellation Based on Stacked-Capacitor, N-Path Switched-Capacitor Delay Lines Achieving >54dB SIC Across 80MHz BW and >15dBm TX Power-Handling
6.6 Full-Duplex Receiver with Wideband Multi-Domain FIR Cancellation Based on Stacked-Capacitor, N-Path Switched-Capacitor Delay Lines Achieving >54dB SIC Across 80MHz BW and >15dBm TX Power-Handling
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6.6 基于堆叠电容器、N 路径开关电容器延迟线的具有宽带多域 FIR 消除功能的全双工接收器，可在 80MHz 带宽内实现 >54dB SIC 和 >15dBm TX 功率处理
DOI：
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发表时间：
2021
期刊：
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通讯作者：
H. Krishnaswamy
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作者：
A. Nagulu;Sasank Garikapati;Mostafa Essawy;I. Kadota;Tingjun Chen;A. Natarajan;G. Zussman;H. Krishnaswamy
全双工（FD）收发器仍然是一个重大挑战，因为它们需要消除100$ dB的高水平自干扰（SI）、重建大SI信道延迟扩展以及实时消除器自适应。基于频域均衡（FDE）[1]、[2]的SI消除器需要多个可广泛调谐的高功耗高Q滤波器，而基于FIR的时域均衡（TDE）[3] -[5]的SI消除器需要高分辨率的大延迟（参见图6.6.1，了解基于SI通道隔离曲线的系统仿真，其中TX-RX泄漏跨越数十纳秒）。此外，支持$\sim20$ dB的实际天线接口隔离需要低损耗消除器，并强调消除器噪声和线性度[6]。本文介绍了一种N路开关电容延迟线，它具有叠层电容电压增益，同时在大带宽上实现了近10纳秒的RF实时延迟（ii）新的LNTA消除器，其中消除器的FIR加权、求和和输出缓冲器被吸收到LNTA中，以及（iii）利用抽头非理想性的分析建模的闭环自适应算法，其降低了计算复杂性和数据存储。利用16抽头RF消除器，工作频率范围为DC至1GHz，延迟范围为0.25ps至8 ns $（与[5]相比为8倍，与[4]相比为40倍）和延迟范围为10 ns至85 ns的复数加权8抽头BB消除器，FD接收机实现了（i）在200 MHz至1 GHz范围内的可调谐操作，（ii）在800 MHz下工作时，40 MHz（80 MHz）范围内的宽带SI抑制高达65 dB（54 dB）（比[5]高13 dB，同时实现2倍的抵消带宽），（iii）NF适度下降0.8 dB（2.8dB），而（iv）在初始环行器隔离仅为23 dB（比[1] -[4]好11至18 dB）的情况下，处理高达+15 dBm（比[5]高6dB）的TX功率。
Full-duplex (FD) transceivers remain a significant challenge as they require $\gt 100$ dB of cancellation of high levels of self-interference (SI), recreation of large SI channel delay spreads, and real-time canceler adaptation. SI cancelers based on frequency-domain equalization (FDE) [1], [2] demand multiple widely-tunable power-hungry high-Q filters, while those based on FIR-based time-domain equalization (TDE) [3] –[5] require large delays with fine resolution (see Fig. 6.6.1 for a system simulation based on the isolation profile of an SI channel, where the TX-RX leakage spreads across several 10s of nanoseconds). Additionally, supporting realistic antenna interface isolations of $\sim20$ dB requires a low-loss canceler and stresses canceler noise and linearity [6]. This work introduces - (i) an N-path switched-capacitor (SC) delay-line with stacked-capacitor voltage gain while enabling nearly ten nanoseconds of RF true-time delay across a large BW (DC to 1GHz), (ii) a new LNTA canceler where the FIR weighting, summation, and output buffer of the canceler is absorbed into the LNTA, and (iii) a closed-loop adaptation algorithm leveraging analytical modeling of tap non-idealities that reduces the computational complexity and data storage. Leveraging a 16-tap RF canceler operating across DC to 1GHz with delays ranging from 0.25ps to 8ns $(8 \times$ compared to [5] and $40 \times$ compared to [4]) and a complex-weighted 8-tap BB canceler with delays ranging from 10ns to 85ns, the FD receiver achieves (i) tunable operation across 200MHz to 1GHz, (ii) wideband SI suppression of up to 65dB (54dB) across 40MHz (80MHz), when operating at 800MHz (13dB higher than [5] while achieving $2 \times$ cancellation BW), with (iii) modest NF degradation of 0.8dB (2.8dB) for the low-power mode (high-power mode), while (iv) handling TX power of up to +15 dBm (6dB higher than [5]) across an initial circulator isolation of only 23dB (11 to 18dB better than [1] –[4]).