Digital beamforming with bandpass ADCs and bitstream processing Slides

Abstract: Multi-antenna systems and beamforming play a critical role in mm-wave communication by counteracting path loss. In addition, spatial filtering and multiplexing further increase channel capacity. Moreover, large arrays are desirable, as an arrayed system's SNR and spatial selectivity improve with more extensive array size. In addition, digital arrays offer better flexibility, reconfigurability, and beam accuracy and enable efficient multi-beam generation.
Bitstream processing (BSP) is an emerging technique for power and area-efficient digital beamforming. An array of bandpass continuous-time ADCs digitizes high IF signals, relaxing anti-alias requirements and eliminating the need for analog IQ down conversion. BSP directly operates on the undecimated ADC quantizer outputs to reduce the power consumption and die area of digital processing. We demonstrate the potential of this approach in a single-chip 16-element digital beamformer. We also show that BSP can facilitate both true-time-delay and phased array beamforming.