The objective of this research is to demonstrate proof-of-concept of a new multi-antenna wireless transceiver design that promises dramatic improvements in capacity and power/bandwidth efficiency compared to the state-of-the-art systems. The approach is based on a new hybrid analog-digital multiple-input-multiple-output architecture that enables a continuous-aperture phased-array operation and optimum beam agility. The new analog-digital interface is realized via a novel phased-array architecture - a high-resolution discrete lens array - that computes an analog spatial Fourier transform and enables optimum link adaptation through beam agility. The integrated theoretical-experimental research plan includes development of basic theory and prototype development to demonstrate the potential of the new transceiver design. Intellectual Merit: The compelling performance gains promised by the proposed agile transceiver rely on several innovations relative to the state-of-the-art, including: i) Integration of analog and digital processing for optimum adaptation; ii) Integration of coherent beam-forming and spatial multiplexing; iii) Source-channel matching for capacity maximization; and iv) High-resolution discrete-lens-array-based operation for dynamic beam control. The project is expected to advance the state-of-the-art of wireless communications on both theoretical and practical fronts, including spurring interdisciplinary research into new transceiver architectures and new conceptual paradigms for antenna array design.
The broader impacts of this interdisciplinary project include multi-disciplinary training of graduate and undergraduate students, involvement of underrepresented students in research, student participation in research meetings, research dissemination via presentations, publications and the web, incorporation of research results into graduate and undergraduate courses, and collaboration with other research groups and industry for cross-fertilization of ideas and technology transfer.
The theoretical and experimental results of this EAGER project provide an initial proof-of-concept demonstration of a new architecture for wireless communication that can potentially achieve unprecedented multi-Gigabits/sec speeds (1-1000 Gbps) at millimeter-wave (10-100GHz) frequencies. The architecture is based on the concept of beamspace communication - simultaneously communicating data through multiple highly-directional, high-gain and extremely narrow spatial beams. It achieves efficient beamspace communication through a novel antenna structure called a lens array. The new wireless architecture has the potential of transformative advances in wireless communications on several critical fronts: unprecedented multi-Gigabits/sec data rates for meeting the exploding wireless bandwidth requirements; highly directional communication for reduced interference and enhanced security; smart base-station design for serving hundreds or thousands of users at Gigabit speeds; efficient and optimal access to the electromagnetic (EM) spectrum. In the longer term, the new architecture could lead to new approaches to communication and sensing at mm-wave, terahertz, optical and higher frequencies. Intellectual Merit: The theoretical and experimental results of this project provide an initial proof-of-concept of a new wireless transceiver architecture -- continuous aperture phased MIMO -- that exploits advances in MIMO (multiple input multiple output) communication theory, phased arrays, and metamaterial-based antenna design to fully harness the spatial dimension. CAP-MIMO leverages a novel phased array structure -- a high-resolution Discrete Lens Array (DLA) -- that enables analog beamforming for achieving optimum beamspace communication with the lowest transceiver complexity. Unlike conventional MIMO systems, CAP-MIMO can fully exploit the large number of spatial degrees of freedom for a variety of critical functions, including: higher antenna or beamforming gain for dramatically enhanced power efficiency; higher spatial multiplexing gain for dramatically enhanced spectral efficiency; and highly directional communication with narrow beams for dramatically reduced interference and enhanced security. These initial results from the EAGER project lay the foundations of a general CAP-MIMO framework for optimizing the performance-complexity tradeoff inherent to high-dimensional MIMO systems at mm-wave and higher frequencies. The generality of the basic underlying theory indicates that the CAP-MIMO framework is applicable to a broad range of operational scenarios, including: point-to-point and point-to-multipoint links; line-of-sight and multipath propagation; multi-beam steering in mobile environments; and wideband operation. Thus, the CAP-MIMO architecture has the potential of transformative improvements in high data-rate communication links in both space and terrestrial environments, under various topology, available spectrum, and complexity/cost constraints. Broader Impacts: The activities in this EAGER project have provided invaluable opportunities for cross-disciplinary training of graduate students and undergraduate students at the intersection of communication theory, signal processing, wireless channel modeling, the physics of wave propagation, electromagnetic theory and antenna design. The activities have exposed the students to three important aspects: i) basic theory, ii) computational modeling, and iii) prototype construction, measurements, and data processing for system evaluation. The findings of the project have been reported at a number of conferences and two journal papers. The activities have also led to a US patent application and the PI is exploring industrial collaborations for development and potential commercialization of the CAP-MIMO technology for emerging applications of mm-wave broadband technology, including multi-Gigabit wireless backhaul links (as a promising alternative to fiber-based backhaul links for connecting an enterprise network to the wired backbone internet), and smart basestations in mm-wave broadband networks.
