GNU Radio Conference 2026

Scalable Phased Arrays with QuadRF

24 Sept 2026, 13:15

30m

Mountain Ballroom (Talley Student Union)

Talk Hardware for GNU Radio Main Track

Speaker

Martin McCormick (Scale RF Inc.)

Description

The proliferation of advanced MIMO and phased-array systems typically requires prohibitive hardware costs and complex, proprietary software stacks. In this presentation, we introduce QuadRF, an open-source 4x4 MIMO software-defined radio development platform specifically designed for experimental phased arrays. Operating in the 4.9–6 GHz (C-band) range, QuadRF brings a novel architectural approach to high-bandwidth signal streaming by circumventing traditional USB or Ethernet bottlenecks. Instead, it utilizes the Raspberry Pi 5’s MIPI CSI-2 (camera) and DSI (display) flexible flat cable connections to stream full-duplex 8+8-bit I/Q data directly to the Pi at 5.6 Gbps.

Our talk will detail the complete system architecture, from the Lattice ECP5 FPGA processing blocks to the seamless integration with GNU Radio and SoapySDR. We will demonstrate how standard camera and display digital interfaces offer an incredibly low-latency, resilient alternative for multi-channel SDR applications, capable of sustaining hundreds of megasamples per second without sample loss.

A key focus of the presentation will be on scalability and synchronization. We will discuss the daisy-chaining mechanism that allows multiple QuadRF tiles to be connected together, sharing digital data alongside a unified clock distribution. Real-world, over-the-air results will be presented, highlighting our sub-centimeter array calibration technique that relies on an Extended Kalman Filter to measure and correct fractional sample delays and phase offsets.

Attendees will leave with an understanding of how to implement scalable, coherent phased arrays using affordable hardware and an entirely open-source ecosystem. The code, hardware schematics, and GNU Radio integration blocks are open-source and readily available to the community, paving the way for further research and innovation in accessible MIMO development.