SWIFT: Coexisting spectrally-dense communications and passive sensing in directed multi-hop sub-millimeter-wave networks

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

Wireless connectivity and networks have experienced dramatic growth in the past decade, benefiting society in commerce, information access, transportation, health, and defense. With strong commercial demand of the spectrum such as for mobile broadband wireless access, the passive uses of spectrum such as radio astronomy and atmospheric science, along with critical active non-commercial services such as global positioning system and weather radar, have been increasingly encroached. Furthermore, the resulting electromagnetic spectrum below 60 GHz have become increasingly overcrowded, bounded by the carrier frequency, even with spectrum-efficient advanced modulation and multi-input multi-output spatially diverse network protocols. In contrast, the electromagnetic spectrum between 300 GHz to 850 GHz is largely unassigned. This provides a unique opportunity to utilize this range of the electromagnetic spectrum, without spectrum crowding and with significant spectrally dense capacity enhancement, while designing a priori the coexistence with passives uses in radio astronomy and atmospheric science. The sub-millimeter wave (smmWave) and terahertz (THz) regions have unique rich spectral signatures for atmospheric constituents and molecules as well as for astronomical science observation, in both thermal emission and rotational-vibrational emission lines. This project seeks to demonstrate the co-designed physical and network layers in the high-data-rate smmWave communication link with the presence of passive uses in atmospheric science and radio astronomy. Chip-scale measurements, designs and nanofabrication will be studied, together with the information theoretic and architectural aspects of the smmWave active-passive communication network. The project will integrate the research with various educational and outreach activities to recruit undergraduate and high-school students in STEM. This project examines a smmWave communication link in directed point-to-point connectivity, in the presence of coexisting smmWave passive-use systems in atmospheric science and radio astronomy. To enable the cross-layer integration, the research will examine proof-of-concept measurements in each of the scientific Thrusts, together with a co-designed communication-sensing testbed. Thrust 1 will examine a photonic-smmWave link and sensing module, with an integrated chip-scale transmitter-receiver-detector block. The narrow-linewidth smmWave radiation encodes high-speed data per channel, with the directed beam coupled to a reconfigurable antenna array for dynamic phase-array beam steering. Four channels will be demonstrated in the link prototype, with a high-sensitivity large dynamic range heterodyne photomixed receiver. In Thrust 2, an adaptive communications testbed will be examined, in the presence of passive users. Spectrally dense scaling and energy-per-bit efficiencies will be studied, along with concurrent passive detection of smmWave molecular spectral signatures. Thrust 3 will study the directivity beam steering of the smmWave link to guarantee low interference for passive users. Spatial footprint, fundamental bounds on the network capacity, multi-input multi-output and sensing schedules will be quantified. An expanded network with multiple source-destinations and passive users will be studied. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.