Collaborative Research: Applied Electromagnetic Characterization of Wideband Multi-Array Communication

Drexel University, Philadelphia PA

Investigators

Abstract

This collaborative project (with Heath at UT-Austin, proposal 03-22975), performing an experimental investigation of Multiple-Input Multiple-Output (MIMO) systems, aims at designing and testing novel antenna systems for wideband digital wireless communication systems to provide designers with new data points. The experimental program is divided between two testbeds. The first testbed (implemented at Drexel) focuses on the electromagnetic propagation characteristics of the MIMO channel, while the second testbed (implemented at UT-Austin) makes use or the electromagnetic characterization to examine the channel impact of the higher network layers. Systems with MIMO communication links, fueled by the increasing demand for high-speed and high-quality mobile communication, use multiple antenna arrays, one at the transmitter and one at the receiver, to take advantage of the spatial dimension of the propagation channel. When properly designed, multi-array communication links can provide multi-fold increases in link throughput in addition to reductions in channel variation which in turn may be used to provide higher rates to single users, lower delay links, or to allow multiple users to coexist in the spatial channel. Because of this advantages, MIMO capability is being considered for indoor local area networks (LAN)s, cellular multimedia data networks, and broadband wireless access. However, without careful design, the results of electromagnetic interaction, such as mutual coupling, may correlate the channel coefficients, thus resulting in a loss in terms of capacity or error probability. Real experimental propagation and experimental data are needed to correlate the tradeoffs between different antenna designs, antenna placements, scattering models, channel bandwidth, and transceiver algorithms. This research involves designing and building two experimental platforms for wideband MIMO propagation channel measurement and real-time prototyping. The prototype constructed at Drexel will be used for the low-level electromagnetic characterization of the MIMO propagation channel, while the UTA prototype will be used to demonstrate the impact of this characterization on higher layers. Thus the work involves Estimating and analyzing wideband MIMO propagation channels, Verifying performance loss due to mutual coupling and electromagnetic interactions, and Studying advanced MIMO architectures in which the antennas are distributed throughout the environment. The research plan involves a synergy of field experimentation with prototype hardware backed by computational electromagnetic (CEM) modeling and communication theory. Broader impacts are addressed in several ways: Introducing jointly concepts of communications and applied electromagnetics to advanced undergraduate and graduate courses (rather than as separate courses), Deploying interdisciplinary course modules jointly taught at both universities, generating a lab manual containing a series of experiments and a set of lecture notes, Providing the data records collected that illustrate concepts critical to design, and Enabling instructors at other universities to incorporate some experimental methods into their teaching.