A Four-Element 500-MHz 40-mW 6-bit ADC-Enabled Time-Domain Spatial Signal Processor

Ghaderi, Erfan; Sk, Gupta

doi:10.1109/jssc.2020.3040702

Cited by 11 publications

(8 citation statements)

References 23 publications

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“…Delay control with sub-ns accuracy has been demonstrated in full-duplex circuits for interference cancellation [12]. Recently, authors of [13] have shown accurate delay control with 0.1 ns resolution and with 6-bit control (64 values until 6.4 ns), which satisfies the requirement of mmFlexible.…”

Section: B Range Of Delay Element In Dpamentioning

confidence: 96%

mmFlexible: Flexible Directional Frequency Multiplexing for Multi-user mmWave Networks

Jain¹,

Vennam²,

Subbaraman³

et al. 2023

Preprint

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Modern mmWave systems have limited scalability due to inflexibility in performing frequency multiplexing. All the frequency components in the signal are beamformed to one direction via pencil beams and cannot be streamed to other user directions. We present a new flexible mmWave system called mm-Flexible that enables flexible directional frequency multiplexing, where different frequency components of the mmWave signal are beamformed in multiple arbitrary directions with the same pencil beam. Our system makes two key contributions: (1) We propose a novel mmWave front-end architecture called a delay-phased array that uses a variable delay and variable phase element to create the desired frequency-direction response. (2) We propose a novel algorithm called FSDA (Frequency-space to delay-antenna) to estimate delay and phase values for the real-time operation of the delay-phased array. Through evaluations with mmWave channel traces, we show that mmFlexible provides a 60-150% reduction in worst-case latency compared to baselines 1 .

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Section: B Range Of Delay Element In Dpamentioning

confidence: 96%

mmFlexible: Flexible Directional Frequency Multiplexing for Multi-user mmWave Networks

Jain¹,

Vennam²,

Subbaraman³

et al. 2023

Preprint

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“…Recent time delay units (TDU) have used either of the following methods: transmission line [11], LC delay network [12], [13], RF re-sampling [14], Gm-C all pass filter [15], [16], time interleaved switched capacitor circuit [3], [4], [17], and digital delays [18]. The conceptual implementations of these TDUs are shown in Fig.…”

Section: Proposed Ttd Ssp Circuit Implementationmentioning

confidence: 99%

“…Uniform-frequency response across wide modulated bandwidths can be realized using the concept of true-time-delay (TTD) introduced with baseband delay elements. Large delay range-to-resolution ratios realized using this technique [3], [4] has opened opportunities for fast beam training algorithms in large-scale arrays without needing additional external constructs. For example, Rotman Lens [5] based beamforming can be leveraged for beamtraining.…”

Section: Introductionmentioning

confidence: 99%

Multi-Mode Spatial Signal Processor with Rainbow-like Fast Beam Training and Wideband Communications using True-Time-Delay Arrays

Lin¹,

Puglisi²,

Boljanovic³

et al. 2022

Preprint

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Initial access in millimeter-wave (mmW) wireless is critical toward successful realization of the fifth-generation (5G) wireless networks and beyond. Limited bandwidth in existing standards and use of phase-shifters in analog/hybrid phasedantenna arrays (PAA) are not suited for these emerging standards demanding low-latency direction finding. This work proposes a reconfigurable true-time-delay (TTD) based spatial signal processor (SSP) with frequency-division beam training methodology and wideband beam-squint less data communications. Discrete-time delay compensated clocking technique is used to support 800 MHz bandwidth with a large unity-gain bandwidth ring-amplifier (RAMP)-based signal combiner. To extensively characterize the proposed SSP across different SSP modes and frequency-angle pairs, an automated testbed is developed using computer-vision techniques that significantly speeds up the testing progress and minimize possible human errors. Using seven levels of time-interleaving for each of the 4 antenna elements, the TTD SSP has a delay range of 3.8 ns over 800 MHz and achieves unique frequency-to-angle mapping in the beamtraining mode with nearly 12 dB frequency-independent gain in the beamforming mode. The SSP is prototyped in 65nm CMOS with an area of 1.98mm 2 consuming only 29 mW excluding buffers. Further, an error vector magnitude (EVM) of 9.8% is realized for 16-QAM modulation at a speed of 122.8 Mb/s.

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“…When compared with LTI all-passive LC-based delay circuits (e.g., [7], [8]), the clock-path delay control, similar to that in switched-capacitor delay circuits [1], [14], [20], enables compact, low-loss, and high-resolution delay tuning as it avoids having many series LC sections that are needed to achieve fine delay resolution. The delay non-reciprocity also helps to further reduce the delay line size by half compared with its LTI reciprocal counterpart as discussed under the context of a switched-capacitor delay line design in [1].…”

Section: Ghz Andmentioning

confidence: 99%

“…N-path RF filters with ≥10-ns delay have been demonstrated but have a very limited delaybandwidth product, resulting in narrowband operation [5], [12], [13]. Compared with an N-path filter, an RF switchedcapacitor sampler has a larger delay-bandwidth product hence supporting broad instantaneous bandwidth [4], [14]- [18]. However, an RF switched-capacitor sampler has high insertion loss when used in RF systems with resistive (e.g., 50 ) interfaces; this high insertion loss is due to the fact that the RC time constant is much smaller compared with the switch on-time in a sampler.…”

mentioning

confidence: 99%

A Commutated-LC RF Broadband Delay Circuit

Ming

Yang

Zhou

2022

IEEE J. Solid-State Circuits

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A Four-Element 500-MHz 40-mW 6-bit ADC-Enabled Time-Domain Spatial Signal Processor

Cited by 11 publications

References 23 publications

mmFlexible: Flexible Directional Frequency Multiplexing for Multi-user mmWave Networks

mmFlexible: Flexible Directional Frequency Multiplexing for Multi-user mmWave Networks

Multi-Mode Spatial Signal Processor with Rainbow-like Fast Beam Training and Wideband Communications using True-Time-Delay Arrays

A Commutated-LC RF Broadband Delay Circuit

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