  The deployment of cellular spectrum in licensed, shared and unlicensed
spectrum demands wideband sensing over non-contiguous sub-6 GHz spectrum. To
improve the spectrum and energy efficiency, beamforming and massive
multi-antenna systems are being explored which demand spatial sensing i.e.
blind identification of vacant frequency bands and direction-of-arrival (DoA)
of the occupied bands. We propose a reconfigurable architecture to perform
spatial sensing of multi-band spectrum digitized via wideband radio front-end
comprising of the sparse antenna array (SAA) and Sub-Nyquist Sampling (SNS).
The proposed architecture comprises SAA pre-processing and algorithms to
perform spatial sensing directly on SNS samples. The proposed architecture is
realized on Zynq System on Chip (SoC), consisting of the ARM processor and
FPGA, via hardware-software co-design (HSCD). Using the dynamic partial
reconfiguration (DPR), on-the-fly switching between algorithms depending on the
number of active signals in the sensed spectrum is enabled. The functionality,
resource utilization, and execution time of the proposed architecture are
analyzed for various HSCD configurations, word-length, number of digitized
samples, signal-to-noise ratio (SNR), and antenna array (sparse/non-sparse).
