ESR1: Maryem Tanveer
System architecture definition and development of RF synchronisation concepts
Based on user-scenarios, a basic DM-MIMO system design will be developed along with its interfaces and system-level specifications. Then, a local oscillator (LO) synchronisation method of the various transmit and receive channels of the RRHs will be developed. Synchronisation is critical for coherent beam-forming but still a major challenge for the highly cost-driven wireless infrastructure market. The ESR will investigate a coupling scheme inspired by A. Agrawal et al. where the coupling is achieved between adjacent PLLs by using moderately high reference clock signals (e.g. 3.5 GHz). This is very suitable for scaling of large transceiver arrays. Furthermore, synchronisation concepts and related circuit blocks between remote radio transceivers will be studied.
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ESR2: Marijana Krivic
Best practices design guidelines to cope with uncertainty propagation through the design cycle
The complexity of designs is continuously growing, also increasing the number of performance-critical parameters. Model uncertainty plays an important role in the final design performance. Therefore, the goal of this project is to test the limits of the current design flows and analyse how uncertainty, generated at the model, propagates into the realised circuit. Starting from existing structures provided by project partners, a modelling study will be performed, followed by fabrication and characterisation, which allow to link back the reality to the simulation results. Focus will be the semiconductor technology used in the consortium (GaN, BiCMOS) in the mm-wave range. Out of this investigation, a ‘cookbook’ of best practices will be generated and widely published. Design guidelines will be shared within the network to help improving the results of each ESR.
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ESR3: Roger Argaez-Ramirez
Power amplifier and antenna co-design strategy for optimised efficiency
The active impedance of an antenna element inside an array varies significantly over the scan range of a single beam. When considering DM-MIMO, even several simultaneous beams will be generated, which affect the antenna impedance even further. As the efficiency of a power amplifier (PA) depends heavily on the connected load impedance, the goal of this project is to develop a strategy to design PAs with optimised energy efficiency under changing load conditions and linearity constraints. We will also explore wideband PA-antenna co-design strategies where the antenna could simultaneously perform power combining and back-off efficiency enhancement. This is complemented with analogue and digital linearization techniques as needed to meet the spectrum and linearity.
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ESR4: Yingqi Zhang
Reconfigurable active-antenna array architectures for mobile users in mm-wave communications
This project aims to find energy-efficient and highly-compact 2-D beam-steerable array solutions at W-band, considered as future enabling technologies for beyond-5G applications. As a building block of the hierarchical beam-steering, the subarray consists of a quasi-optical feed and radiating elements. Based on the Gap Waveguide technology, the subarray architecture is high-efficient (low-loss), wide-band (>20%) and wide-scan compared to state-of-art designs; while the contactless structure allows co-integration of 1-bit phase shifters within the antenna elements, to realize a compact and simple active beam-steerable array.
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ESR5: Adriana Briseno
Strategies for energy-efficient high EIRP generation in mm-wave wireless radio links
For mm-wave wireless links, the link budget will be tighter than for sub-6 GHz systems due to the limited available transmit power and significantly higher free-space path loss. To facilitate high availability and reliability for mobile users, free-space power combining and beamforming are essential parts of the antenna system. While pure digital beam-forming provides the best functionality in this respect, analogue beam-forming is not only less costly but also requires less energy during operation. On the other hand, for analogue beam-forming it is more difficult to find the optimal beam-forming vector in a dynamic scenario. In this sub-project, strategies for hybrid analogue-digital beam-forming and spatial multiplexing in combination with DM-MIMO will be explored and optimised.
ESR6: Kateryna Smirnova
Energy-efficient and low-cost active front-ends for DM-MIMO
In a massive MIMO system, the mm-wave front-ends should be low-cost, energy-efficient and should able to perform frequency translation with minimal distortion and low-noise. Classical front-end architectures will not meet all of the requirements simultaneously, in part due to limited gain at the envisioned operational frequencies. Emerging front-end architectures built upon passive resistive mixers and N-path filters are very promising candidates for the envisioned MyWave system. In this project, the ESR will investigate the application of the mixer-first front-end topology to realize extremely hardware-efficient mm-wave transceiver units. By shifting signal-conditioning to baseband frequencies, highest possible energy-efficiency will be achieved. Part of this project will concentrate on developing new hardware strategies for hybrid beamforming and carrier synchronization adapted to the passive-mixing front-end architecture.
ESR7: Kirill Alekseev
Analogue Radio-over-fibre-fed antennas for massive deployment
For implementing DM-MIMO, a large amount of antennas at different locations is required. In order to allow for a cost-efficient implementation, these antenna systems as well as their front-haul connection must be low-cost and highly robust. This project aims at developing such antenna systems by employing analogue radio-over-fibre (ARoF). Using this approach, the hardware complexity is concentrated in the central processing unit, resulting in a low-complexity antenna front-end design. The challenge in this project lies in the dense co-integration of photonic and electronic ICs into the antenna structure. For the electronics, the amplifiers developed in the project will be used. For the photonic ICs (PICs), the use of commercial off-the-shelf components is anticipated. If required, TUE’s own InP PIC process is available to design and fabricate required components.
ESR8: Dmitrii Kruglov
Co-optimised antenna-circuit module integrating contactless interconnects
The goal of this project is to synthesize a new multifunctional ‘material’ consisting of conducting, non-conducting, and semi-conducting materials using a recently introduced method referred to as Deep Integration. The passive linear parts of the material are modelled as spatially distributed inductors (permeability), capacitors (permittivity), and resistors (conductivity). This design space is however restricted to both the Back-End-of-Line (BEoL) of an Integrated Circuit (IC) and its package. The active layer of the IC embeds a grid of transistors that couples the field in a contactless quasi-optical manner from BEoL to the Antenna-in-Package (AiP). This multi-material system is then jointly optimized to achieve high energy efficiency. Note that no standard interface reference impedances will be used, resulting in a compact globally optimal antenna-amplifier module.
ESR9: Moise Safari Mugisho
Highly efficient digital amplifier architecture based on GaN technology
Switch-mode power amplifier concepts have so far been considered for advanced amplifier concepts at frequencies below 3 GHz. At mm-waves, classical power technologies did so far not provide sufficient robustness to achieve high-switching speed while maintaining high power output. Nowadays most advanced GaN semiconductor technologies do allow to create high power levels at mm-wave clock speeds. Thus, new circuit concepts are required at mm-waves to create new amplifiers for array concepts and to create efficient digital-switch structures for efficiently creating RF power and enhancing overall efficiency.
ESR10: Bharath Kumar
Efficient power combining of GaN mm-wave amplifiers
For radio links, the achievement of high power linear operation is required to achieve high data-rates at maximum power added efficiency. At mm-wave frequencies, classical power combining to achieve high EIRP and matching to a 50 Ohm antenna interface creates a lot of losses, which are prohibitive even for GaN. Thus, new concepts are required at mm-waves to create efficient multi-chip structures that efficiently feed the power directly to a planar low-cost and low-loss PCB. In this way, significant linear power levels are achieved, which are way beyond today’s linear power levels and without having to consider complex classical split-block approaches for waveguide combining.
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ESR11: Nazanin Farid Mohajer
Channel emulation platform for system testing mm-wave mobile user scenarios
Reverberation chambers have been proposed to test mobile telecommunication equipment and protocols. However, a reverberation chamber does not exhibit all the properties of real-life communication channels. This can be obtained by loading a reverberation chamber with appropriately placed absorbing materials. In this project, we will study, design and test a loaded reverberation chamber to emulate a specific multi-path environment. To also capture the dynamics of moving users, we will develop a wall-tiling system that has the capability of switching the behaviour of individual tiles from purely reflecting to purely absorbing, controlled by an electronic switch. The complete system will be designed and integrated in TUE’s reverberation chamber, which will serve as the test platform for the distributed base-station system developed in MyWave.
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ESR12: Mohammad Shahid
Multi-physics modelling for improving design-time and energy-efficiency of highly integrated active antenna arrays
At mm-waves, the active front-end components have to be directly integrated with the radiating elements. Due to the high density of radiating elements, the heat generated by the electronics has a major impact on the system performance and has to be taken into account during the design process. For this, accurate multi-physics modelling tools are required. This project aims at developing such a modelling framework by decomposing the structure into different computational domains. Each domain is calculated using the most suitable computational method for that physical structure. The interaction between the domains is taken into account by generalised (3D) scattering operators at the interfaces between the domains. In this way, high computational efficiency and accuracy can be achieved, reducing the amount of design cycles while optimising the energy efficiency of the overall solution.
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ESR13: Mehrangiz Ensan
Energy efficient signal processing techniques for DM-MIMO systems
In this project, strategies will be developed that make efficient communication possible. In principle, multiple orthogonal strategies have to be realised by the RRH’s, one for each transmitting/receiving user. The RRH’s act as relays between source or destination and the users. It is the objective of this project to design the signal processing algorithms and protocols for the small-scale DM-MIMO test-bed of project P15. The project is based on multi-user information theory, more specifically broadcast, multiple-access and relay transmission protocols. To make transmission reliable, the application of coding techniques is crucial.
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ESR14: Jafar Banar
Digital array calibration techniques and synchronisation for DM-MIMO
At mm-waves, the active front-end components have to be directly integrated with the radiating elements. Due to the high density of radiating elements, the heat generated by the electronics has a major impact on the system performance and has to be taken into account during the design process. For this, accurate multi-physics modelling tools are required. This project aims at developing such a modelling framework by decomposing the structure into different computational domains. Each domain is calculated using the most suitable computational method for that physical structure. The interaction between the domains is taken into account by generalised (3D) scattering operators at the interfaces between the domains. In this way, high computational efficiency and accuracy can be achieved, reducing the amount of design cycles while optimising the energy efficiency of the overall solution.
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ESR15: Husileng Bao
Digital Radio-over-Fibre for flexible mm-wave DM-MIMO systems
In this project we will explore and push the frequency and capacity limits of all-digital radio-over-fibre as a means of realizing flexible mm-wave DM-MIMO systems. We will work towards a test-bed capable to support key communication principles between distributed antennas, which will be used to determine and experimentally demonstrate the required levels of communication, including RF-synchronisation and beamforming functionalities between distributed radio units. The project will include the design and integration of key electrical- and optical hardware components and algorithms with the goal of maximizing communication system performance.
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