Terahertz based Ultra High Bandwidth Wireless Access Networks

Project Information

TERAPOD

Grant agreement ID: 761579

DOI

10.3030/761579

Project closed

EC signature date 2 June 2017

Start date 1 September 2017

End date 31 May 2021

Funded under

• INDUSTRIAL LEADERSHIP - Leadership in enabling and industrial technologies - Information and Communication Technologies (ICT)

Total cost

€ 3 467 593,75

EU contribution

€ 3 467 593,75

Coordinated by

SOUTH EAST TECHNOLOGICAL UNIVERSITY
Ireland

Periodic Reporting for period 2 - TERAPOD (Terahertz based Ultra High Bandwidth Wireless Access Networks)

Reporting period: 2018-09-01 to 2021-05-31

Summary of the context and overall objectives of the project

The overall TERAPOD objective is to investigate and demonstrate the feasibility of ultra-high bandwidth wireless access networks operating in the TeraHertz (THz) band. The TERAPOD THz communications system was developed, driven by ‘beyond 5G’ usage scenario requirements, and was planned to be demonstrated within the operational setting (Dell EMC Data Center) and to significantly progress innovations across the full communications protocol stack.

TERAPOD pursued the ambitious vision of the short-range Tbps wireless connectivity paradigm, by exploiting three of the most promising emerging THz device technologies, namely (1) resonant tunnelling diodes (RTDs), (2) uni-traveling-carrier photodiodes (UTC_PDs) and (3) Schottky barrier diodes (SBDs) to enable the development and integration of the building blocks required for ultra-broadband communications in the THz spectrum. Therefore, TERAPOD employed a holistic approach where multiple technologies are explored simultaneously in order to identify the architectures where the advantages of each technology can be fully extracted instead of relying on each of the technologies separately. In fact, no single technology will be able to support the requirements of developing THz transceivers with high speed optical/wireless interfaces and electrical/wireless interfaces and receiver architectures. The vision of TERAPOD project is that, to push the boundaries of the THz communications, the combination and integration of multiple technologies is required and should be explored to pave the way for future Tbps wireless communications. Achieving the Tbps wireless connectivity paradigm requires the employment of very high frequency bands above 300 GHz and up to 1 THz, since the frequency bands currently in use (below 100 GHz) do not seem sufficient to accommodate the predicted future data-rate requirements. In fact, while previous research below 100 GHz has been focused on improving spectral efficiency as well as spatial efficiency (with MIMO and beamforming), the use of frequency bands where ultra-high bandwidth channels are available allows for relaxed spectral efficiency requirements which translates into reduced energy consumption, whereas the capacity scale-up of systems operating below 100 GHz will certainly result in a linear scale-up in energy consumption which is problematic.

The project has four general objectives:

1. Advance the TRL of THz communications components and systems out of the lab and towards industrial environments, within the context of beyond 5G usage scenario requirements.

2. Demonstrate the feasibility of THz communications systems in beyond 5G scenarios through a fully integrated data centre demonstrator.

3. Address the non-technical barriers to adoption of THz communication in the area of Regulation and Standards.

4. Promote scientific research and innovation of THz communications systems in Europe.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

TERAPOD has defined a set of system level requirements for integration of THz communications systems into data centre environments. These requirements focused on the environmental and geometric constraints imposed by the data centre, as well as high level performance requirements for the wireless channel. These requirements were used to inform design considerations both at the hardware and software levels.

With regards to the THz communications system component development, TERAPOD has taken a multi-facet approach by not relying on a single technology option but a set of three technologies for transmission and detection. Uni-travelling Carrier Photodiodes (UTC-PDs) and Resonance Tunnelling Diodes were developed as sources, and Schottky Barrier Diodes were used as detectors.

An extensive measurement campaign was carried out to characterise the THz channel within a data centre. This enabled the development of accurate physical layer simulators for the development of physical and data link layer protocols.

A physical layer simulator has been developed. Data Link Layer protocol analysis at WIT initially focused on framing and error control under varying error models and was subsequently improved with the aim of developing accurate framing and error control strategies for THz communications systems.

TUBS successfully performed the first channel characterisation measurements in a real data centre (at Dell EMC and WIT) and NPL established a world-leading test rig for THz devices.

TERAPOD has made important strides in THz comms links and the headline TERAPOD project target was reached: 100 Gbps using 300 GHz over 1-10 m.

TERAPOD has demonstrated the project target of a 100 Gbps wireless bridge at 300 GHz (albeit in the lab, rather than a real data centre). This represents an important stepping-stone towards 1 Tbps THz links.

Standards
This project has played an important role in driving standards in the area of THz communications. TERAPOD has made four contributions to IEEE 802.15 SC THz, has observed the outcome of spectrum regulations at WRC 2019 and has produced several documents in the area of “Recommended Practice on Device Measurements”. The findings from TERAPOD’s simulations of IEEE Std. 802.15.3d-2017 in the data centre environment may provide relevant input for the revision of this standard, which is scheduled for autumn 2021.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

TERAPOD has been successful in moving the TRL and performance of each of the target THz components and supporting technology infrastructure which were developed in the project, and these were combined to extend the state-of-the-art of THz comms systems and links.

Taking each of the elements in turn, TERAPOD can boast the following advances:

• UTC-PDs
o Fully packaged UTC-PDs operating at 300 GHz with power an order of magnitude higher than commercially available devices

• RTDs
o 300 GHz devices beyond state-of-the-art in terms of DC-RF conversion efficiency (from <1 % to >10 %)
o Epitaxial designs capable of RF output power from ~1 mW at 300 GHz to >10 mW
o Successfully packaged RTD W-band transceiver

• SBDs
o A novel low barrier mixer (270-320 GHz) showed excellent performance and sets the state-of-the-art for low LO power operation
o Successfully operated with RTD and UTC inputs

• Antennas
o Design and fabrication of 300 GHz BCB-based 1×4 planar antenna array
o Scalable high-gaussicity split-block diagonal horn antenna for integration with sub-THz devices (patent application GB2001401.5)

• PICs
o Validated PIC-based scalable integrated optical beam forming mechanism for THz beam steering

• Protocols
o Feasibility of integration of THz links in a data centre using available devices and communications protocols was demonstrated

• Simulation tools
o Link Level Simulator providing a universal framework for simulation of cutting-edge communications systems
o Realistic interference analysis of "top of rack" links in a real data centre
o First tests of THz devices directly with data centre equipment

• Characterisation
o A spatial beam profiling rig for THz emitters was established and a broadband lamellar interferometer was built for spectral characterisation
o The first detailed THz channel measurements and characterisation were carried out in a real data centre.

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TERAPOD System Architecture