NICOP - MULTI-DIMENSIONAL SIGNAL DESIGN FOR WIDEBAND HF LINKS
Abstract
The purpose of the proposed project is to design an advanced, adaptive, distributed physical layerarchitecture, which utilizes all three relevant channel degrees of freedom, namely Space-Time-Frequency over the High Frequency (HF) band, which will be able to provide high data-rates.The utility of such an architecture is envisioned for long range communications, such as fleet-toshore,airborne platforms-to-base, or multi-vehicle platoons to headquarters, which require highrateservices, heretofore unavailable to legacy HF narrowband systems. Current interest in thetopic is manifested in the recent standard MIL-STD-188-110C-Appendix-D. The key innovationin this project is to leverage a detailed knowledge of the HF channel, which tends to be spectrallypolluted by narrowband interferers, while at the same time triply spread (in space, frequency andtime) into a flexible signal design that harnesses the potential of all STF dimensions in acoordinated manner, therefore mitigating the possible problems appearing in each of themseparately.The proposed research will focus on two complementary directions, which will support theultimate design goal. First, a realistic HF propagation model in the wideband regime will bedeveloped, using detailed methods of propagation physics, which characterize the channel in theaforementioned three dimensions. The analysis will start with the deterministic aspects of thepropagation, which include the reflection from the various ionospheric layers and the effects ofthe earth???s magnetic field. Special attention will be given to the related statistical features of thechannel, in the temporal (Doppler), frequency (delay-spread) and spatial (angle-spread) domains,which characterize the underlying degrees of freedom of the channel. Based on the HF channelcharacterization, the second direction of the project will focus on appropriate signal designswhich realize the potential of the three above dimensions, namely space, time and frequency.The spatial character of the channel will be captured by placing multiple dual-polarized colocatedantennas over spatially distributed platforms, which are coordinated through widebandRF links. When such architecture is created in both ends of the HF communication link, aDistributed Multi-Input Multi-Output (D-MIMO) composite link is created, which can beoptimized, subject to channel quality and dynamics, to include beamforming or to minimize thereceived signal at other, adversary locations. The harnessing of the energy in time and frequencyis affected via Multi-Carrier (MC) signals, of the modern OFDM family, further enhanced bychip spreading in time and/or frequency. These spreading mechanisms not only provide thepotential of energy harnessing of the doubly-spread channel but also yield standard protectionagainst narrowband interference (e.g., extraneous narrowband users). The ultimate scientificgoals of the project are: (a) a thoroughly-vetted W-HF channel model and related simulationcode; (b) a flexible and adaptive signal-design framework that properly matches the activedesign to the channel at hand; (c) a novel D-MIMO architecture for W-HF; and (d) a sequence ofspecific design instantiations, under various channel modes, which offer comparativeconclusions amongst themselves and the baseline MIL-standard. The project will also utilizereal-world measurements, provided gratis by TrellisWare Technologies of San Diego, CA, inorder to assess such solutions in a realistic setting.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 04, 2018
- Source ID
- N629091812141
Entities
People
- Aris L. Moustakas
Organizations
- Office of Naval Research
- United States Navy