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Abstract

We devise a tool-supported framework for achieving power-efficiency of data-flowhardware circuits. Our approach relies on formal control techniques, where the goal is to compute a strategy that can be used to drive a given model so that it satisfies a set of control objectives. More specifically, we give an algorithm that derives abstract behavioral models directly in a symbolic form from original designs described at Register-transfer Level using a Hardware Description Language, and for formulating suitable scheduling constraints and power-efficiency objectives. We show how a resulting strategy can be translated into a piece of synchronous circuit that, when paired with the original design, ensures the aforementioned objectives. We illustrate and validate our approach experimentally using various hardware designs and objectives.
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Bibliography

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[12] S. Miremadi, B. Lennartson, and K. Akesson: A BDD-based approach for modeling plant and supervisor by extended finite automata. IEEE Transactions on Control Systems Technology, 20(6), (2012), 1421–1435, DOI: 10.1109/TCST.2011.2167150.
[13] M. Özbaltan: Achieving Power Efficiency in Hardware Circuits with Symbolic Discrete Control. PhD thesis, University of Liverpool, 2020.
[14] M. Özbaltan and N. Berthier: Exercising symbolic discrete control for designing low-power hardware circuits: an application to clock-gating. IFAC-PapersOnLine, 51(7), (2018), 120–126, DOI: 10.1016/j.ifacol.2018.06.289.
[15] M. Özbaltan and N. Berthier: A case for symbolic limited optimal discrete control: Energy management in reactive data-flow circuits. IFAC-PapersOnLine, 53(2), (2020), 10688–10694, DOI: 10.1016/j.ifacol. 2020.12.2842.
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[19] S. Tripakis, R. Limaye, K. Ravindran, G. Wang, H. Andrade, and A. Ghosal: Tokens vs. signals: On conformance between formal models of dataflow and hardware. Journal of Signal Processing Systems, 85(1), (2016), 23–43, DOI: 10.1007/s11265-015-0971-y.
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Authors and Affiliations

Mete Özbaltan
1
Nicolas Berthier
2

  1. Erzurum Technical University, Erzurum, Turkey
  2. University of Liverpool, Liverpool, England
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Abstract

This research paper discusses an analytical approach to designing the active region of light emitting diodes to enhance its performance. The layers in the active region were modified and the effects of changing the width of quantum well and barrier layers in a multi-quantum light emitting diode on the output power and efficiency have been investigated. Also, the ratio of the quantum well width to the B layer width was calculated and proposed in this research paper. The study is carried out on two different LED structures. In the first case, the width of the quantum well layers is kept constant while the width of the B layers is varied. In the second case, both the quantum well and B layer widths are varied. Based on the simulation results, it has been observed that the LED power efficiency increases considerably for a given quantum well to B layers width ratio without increasing the production complexity. It is also seen that for a desired power efficiency the width of quantum well should be between 0.003 µm and 0.006 µm, and the range of B width (height) should be 2.2 to 6 times the quantum well width. The proposed study is carried out on the GaN-AlGaN-based multi-quantum well LED structure, but this study can be extended to multiple combinations of the semiconductor structures.
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Bibliography

  1. Lenk, R. & Lenk, C. Practical Lighting Design with LEDs. (2nd. ed.) (John Wiley & Sons, Ltd., 2017).
  2. , S. M. & Kwok, K. Ng, Physics of Semiconductor Devices. (4th ed.) (Wiley-Interscience, 2006).
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  7. Shi, J. et al. III-Nitride-based cyan light-emitting diodes with GHz bandwidth for high-speed visible light communicatio. IEEE Electron. Device Lett. 37, 894–897 (2016). https://doi.org/10.1109/LED.2016.2573265
  8. Gong, M. et al. Semi-polar (20–21) InGaN/GaN multiple quantum wells grown on patterned sapphire substrate with internal quantum efficiency up to 52 percent. Appl. Phys. Express. 13, 091002 (2020). https://doi.org/10.35848/1882-0786/abac91
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  12. Song, K., Mohseni, M. & Taghipour, F. Application of ultraviolet light-emitting diodes (UV-LEDs) for water disinfection. Water Res. 94, 341–349 (2016). https://doi.org/10.1016/j.watres.2016.03.003
  13. Liao, Ch.-L. et al. High-speed GaN-based blue light-emitting diodes with gallium-doped ZnO current spreading layer. IEEE Electron. Device Lett. 34, 611–613 (2013). https://doi.org/10.1109/LED.2013.2252457
  14. Quan, Z. et al. High bandwidth freestanding semipolar (11–22) InGaN/GaN light-emitting diodes. IEEE Photon. J. 8, (2016). https://doi.org/10.1109/JPHOT.2016.2596245
  15. Shi, J.-W. et al. III-nitride-based cyan light-emitting diodes with GHz bandwidth for high-speed visible light communication. IEEE Electron. Device Lett. 37, 894–897 (2016). https://doi.org/10.1109/LED.2016.2573265
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Authors and Affiliations

Lokesh Sharma
1
Ritu Sharma
1

  1. Department of Electronics and Communication Engineering, Malaviya, National Institute of Technology, Jaipur, Rajasthan 302017, India
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Abstract

In this study, the concepts of simultaneous user association and resource allocation in non-orthogonal multiple access systems have been investigated. Subscribers are randomly distributed in them. In the paper, a novel cooperative energy harvesting model is introduced so that user equipment near to the base stations acts as relay for further subscribers. In order to consider the local limitations of alternative energy resources, it was assumed that alternative energy would be shared among the base stations by means of the dynamic grid network. In this architecture, non-orthogonal resource allocation and user association frameworks should be reconfigured because conventional schemes use orthogonal multiple access. Hence, this paper suggests a novel approach to joint optimum cooperative power allocation and user association techniques to achieve a maximum degree of energy efficiency for the whole system in which the quality of experience parameters are assumed to be bounded during multi-cell multicast sessions. The model was also modified to develop joint multi-layered resource control and user association that can distinguish the service pattern in cooperative energy heterogeneous systems with non-orthogonal multiple access to obtain more resource optimality than in the current approaches. The effectiveness of the suggested approach is confirmed by numerical results. Also, the results reveal that non-orthogonal multiple access can provide greater energy efficiency than the conventional orthogonal multiple access approaches such as e.g. the MAX-SINR scheme.

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Authors and Affiliations

S.H. HosseiniNazhad
M. Shafieezadeh
A. Ghanbari

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