A mmWave Software-Defined Array Platform for Wireless Experimentation at 24-29.5 GHz

TL;DR

The paper addresses the need for affordable, high-performance mmWave testbeds to prototype 5G/6G air interfaces and beamforming algorithms. It introduces a low-cost (<$6000), open-source mmWave SDA operating from 24 to 29.5 GHz with a 16 TX/16 RX array, RFSoC-PYNQ baseband, a 1.536 GHz sampling bandwidth, and a Python API enabling real-time beamforming experiments. Key findings include a beam steering range of $-45^\circ$ to $+45^\circ$, a 3 dB beamwidth of $20^\circ$, throughput up to $1.613$ Gbps with 64-QAM, and SNR up to $30$ dB at LOS; measurements align with theoretical patterns while highlighting calibration needs. The work enables practical, software-defined experimentation for wireless protocols and beamforming, and discusses calibration for arbitrary pattern synthesis and future mobile deployments within the AERPAW framework.

Abstract

Advanced millimeter-wave software-defined array (SDA) platforms, or testbeds at affordable costs and high performance are essential for the wireless community. In this paper, we present a low-cost, portable, and programmable SDA that allows for accessible research and experimentation in real time. The proposed platform is based on a 16-element phased-array transceiver operating across 24-29.5 GHz, integrated with a radio-frequency system-on-chip board that provides data conversion and baseband signal-processing capabilities. All radio-communication parameters and phased-array beam configurations are controlled through a high-level application program interface. We present measurements evaluating the beamforming and communication link performance. Our experimental results validate that the SDA has a beam scan range of -45 to +45 degrees (azimuth), a 3 dB beamwidth of 20 degrees, and support up to a throughput of 1.613 Gb/s using 64-QAM. The signal-to-noise ratio is as high as 30 dB at short-range distances when the transmit and receive beams are aligned.

Figures (9)

• Figure 1: System diagram of the SDA, including a 16-element direct-conversion phased-array transceiver evaluation kit (EVK) operating across 24-29.5 GHz and using separate antenna arrays for programmable transmit and receive beamforming; multiple balun boards; an rfsoc 2x2 board providing data conversion and programmable digital signal processing; a host computer; and multiple power supplies.
• Figure 2: Physical-layer protocol data unit structure and subcarrier mapping.
• Figure 3: Over-the-air transmit mode measurement setup, using the phased-array evaluation kit in tx mode and a horn antenna connected to a spectrum analyzer as the rx.
• Figure 4: Measured versus ideal beam pattern for an 8x2 tx array steered to broadside together with single-element response.
• Figure 5: Measured beam patterns for TX array, when steered across $\pm$45$\degree$.