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Networking for Wideband Links at Terahertz Frequencies

Description:

TECHNOLOGY AREA(S): Info Systems 

OBJECTIVE: Develop link, transport and networking layer protocols for wideband wireless networks at THz frequencies (above 100 GHz). 

DESCRIPTION: Terahertz band communications is envisioned to answer today’s increasing demand for higher data rates and relieve congestion in conventional RF spectrum. Large available spectrum in terahertz frequencies can enable new high-bandwidth applications that are not feasible with current narrow- band wireless technologies, such as secure airborne communications and in-air sensor data sharing among networks of unmanned autonomous systems. The focus of this research is to develop novel link, transport and network layer solutions that will exploit the full potential of unprecedentedly large bandwidth offered by extremely high-frequency bands. Traditionally, wireless network protocols have been designed with the major constraint being available bandwidth. We are interested in new and novel protocols at link, transport and network layers that do not hold the same assumption but address the challenges stemming from the characteristics of terahertz band. For example, very high path loss caused by atmospheric and molecular absorption at these frequencies calls for the use of highly directional antennas and/or large antenna arrays to focus the beam energy to an intended direction. These directional links as well as beam blockage due to very short wavelengths impose challenges on current medium access strategies that relies on omnidirectional broadcast of control messages. Moreover, in wideband communications systems where tens of Gigabit of data can arrive in a second, the overflow of routing nodes needs to be prevented and fundamentally new routing strategies are required to support ultra-wideband networks. In short, we need link and above protocols to support wideband (10 Gbps and above) communications with intermittent link connectivity (order of seconds or less) due to absorption and blockage, etc. In particular, we are interested in strategies and protocols for dynamic beamforming, beam tracking and alternate path finding in case of beam blockage, in-band and out-of-band link layer protocols, active and passive relaying and multi-hop communication schemes for robust signaling, transport and network layer protocols that can support very high data arrival rates without data loss or queueing issues, synchronization and medium access strategies that consider the effect of very high-speed data rates (tens of Gbps or at least multi-Gbps) in dynamic airborne networks. 

PHASE I: Phase 1 will design algorithms and protocols in link layer and above to support wideband networks in terahertz frequencies and modeling and simulation results should be demonstrated via an appropriate discrete event simulator. The final report should also describe a potential live-demonstration test set up and methodology. 

PHASE II: Phase 2 will develop a prototype system that implements the protocols and validates the results from phase I. A small-scale live-demonstration as well as testing of the algorithms in a relevant environment is expected. Phase 2 should include delivery of software and on-site support for testing. 

PHASE III: Military systems would benefit from both a significant increase in available air to air communications capacity for ISR applications. Developed protocols and strategies will enable wideband communications links to be incorporated into existing airborne networks across many Air Force platforms. Commercial Applications: As new wireless services like 5G are realized, there is an increased market for high frequency devices to help drive the commercial wireless market. The deployment of new wireless network designs incorporating technologies like microcells make consideration of high frequency networks realizable. 

REFERENCES: 

1. T. Kurner and S. Priebe, “Towards THz Communications- Status in Research, Standardization and Regulation,” Journal of Infrared, Millimeter, and Terahertz Waves, vol. 35, no. 1, pp. 53–62, 2014.; 2. I. F. Akyildiz, J. M. Jornet, and C. Han, “Terahertz band: Next frontier for wireless communications,” Physical Communication (Elsevier) Journal , vol. 12, pp. 16–32, Sep. 2014.; 3. J. F. Federici, J. Ma, and L. Moeller, “Review of weather impact on outdoor terahertz wireless communication links,” Nano Communication Networks, vol. 10, pp. 13–26, 2016.; 4. H.-J. Song and T. Nagatsuma, “Present and future of terahertz communications,” IEEE Transactions on Terahertz Science and Technology, vol. 1, no. 1, pp. 256–263, 2011.

KEYWORDS: Wideband, Networking, Terahertz, Medium Access, Link Layer, Transport Layer 

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