Coherent Multiple-Input Multiple-Output Lab

Robert Kossler in the RF Communications and Sensing Lab standing in front of and working on radio equipment

Coherent Multiple-Input Multiple-Output (MIMO) systems represent a special category of MIMO systems. This form of MIMO refers to systems that preserve relative phase and relative gains across ports over sufficient periods of time. The requirement for such coherence and gain matching distinguishes these systems from more conventional MIMO systems and provides capabilities beyond those of conventional MIMO systems.

The Coherent MIMO facility includes integrated coherent MIMO transmission and reception systems to facilitate the conduct of research leveraging inter-channel coherence in communications, radar, and passive sensing. The facility includes a number of PXI-based 4x4 coherent MIMO systems, including a system with bandwidth up to 1GHz. Units are deployed at sites across the campus, including at the Ave Maria Press building for vibration experiments and in the Field Reearch Vehicles (FRVs) for radar experiments; in the RF Remote Sensing laboratory for communications and sensing applications; and in the Wireless Institute laboratory for wired experiments in radar and communications. A unit has been utilized at the Ignition Park Test Facility in downtown South Bend.

Two 4x4 PXI-based coherent multiple-input multiple-output system with radio frequency capability in black case. Labels are included for ATCA, High Speed data streaming, PXIe chassis, and PXIe extension to ATCA.

The coherent MIMO facility also includes a customized 8x8 coherent MIMO transceiver system (left). The system includes raid arrays that enable data from each receive port to be streamed and stored at rates up to 160 MHz. In all cases, phase coherence is maintained (to some tolerance that depends on the frequency of operation) between all transmit and receive ports. This system will ultimately include FPGA array units that will permit processing of real-time data or of collected data streams stored in the raid array, will operate at RF frequencies up to 20 GHz and is configurable as either a single 8x8 coherent MIMO system or two 4x4 coherent MIMO systems. This system represents a customized state-of-the-art resource that, coupled with Notre Dame’s FRVs, provides an exceptional and largely unmatched capability.