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Coherent MIMO Lab


Coherent 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. 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 portable 2x2, 2x4, and 4x4 coherent MIMO systems that can be used for radar, remote sensing, and communications. Units are deployed at sites across the campus, including at Ave Maria Press building for vibration experiments and in the 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 will also be installed at Ignition Park, a facility dedicated to the study of turbomachinery.

The coherent MIMO facility also includes a new, customized $1M 8x8 coherent MIMO transceiver system (see Figure 1). 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. The new 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 and will operate at RF frequencies up to 20 GHz. The system is configurable as either a single 8x8 coherent MIMO system or two 4x4 coherent MIMO systems. The latter configuration is expected to be the configuration of choice when used in the FRVs. The new system is housed in a laboratory within the Fitzpatrick Hall of Engineering. The system represents a customized state-of-the-art resource that, coupled with Notre Dame’s field research vehicles (FRVs), provides an exceptional and largely unmatched capability.

Example Projects

Coherent MIMO systems are being utilized in several projects including the following

Coherent MIMO Communications - Both digital and analog methods of communications are being considered with these architectures, including polarization-based modulation and 4-dimensional modulation techniques

Signal Classification - Coherent MIMO systems are being employed to help classify radio frequency signals.

Dual-Pol Radar - 2x2, 2x4, 4x4 pseudo-monostatic radar systems with dual-pol antennas are being used in research to characterize clutter and targets

Principle Investigator

The PI is Tom Pratt.  He is supported by Rob Kossler (Senior Research Engineer), Eric Jesse (Research Engineer), Ben Strycker (Postdoctoral Researcher), and several Ph.D. students.