| 1. |
- Cheng, Sijia, et al.
(författare)
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A Hardware-in-the-Loop Simulator for mmWave Massive MIMO Using PYNQ Framework
- 2023
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Ingår i: 2023 IEEE 66th International Midwest Symposium on Circuits and Systems, MWSCAS 2023. - : Institute of Electrical and Electronics Engineers (IEEE). - 9798350302103 ; , s. 698-702
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Konferensbidrag (refereegranskat)abstract
- Massive multiple-input multiple-output (MIMO) plays an important role in beyond 5G systems to support high data rate and low latency, especially operating at millimeter-wave frequency bands. In traditional software-based simulators, the simulation time increases exponentially with the number of base station antennas and served users. We propose a hardware-in-loop simulator that combines the flexible software and fast and accurate hardware with Python Productivity for Zynq (PYNQ) framework. The simulation of massive MIMO detection is accelerated by 4 orders of magnitudes with bit-accurate result. With the help of the developed simulator, we explore the design trade-offs between system performance and hardware cost for in-flight-cabin use cases.
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| 2. |
- Cheng, Sijia, et al.
(författare)
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MmWave Massive MIMO Processing in Demanding Environments - An Aircraft Cabin Deployment Study
- 2023
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Ingår i: Conference Record of the 57th Asilomar Conference on Signals, Systems and Computers, ACSSC 2023. - 1058-6393. - 9798350325744 ; , s. 1631-1635
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Konferensbidrag (refereegranskat)abstract
- Massive multiple-input multiple-output (MIMO) technology will continue playing an important role in beyond 5G wireless systems. Fully digital beamforming at the millimeter wave (mmWave) spectrum enables applications that require high data rates and low latency. This paper investigates the development and deployment of mmWave massive MIMO systems in an in-flight cabin environment, from both system performance and hardware implementation aspects. Ray-tracing methods with realistic geometry coefficients captured from commercial airplane models are used to represent this in-door dense environment. A hardware-in-the-loop simulator running on the AMD/Xilinx PYNQ FPGA is leveraged to conduct fast design space exploration. The outcomes of our investigation provide insights and guidelines in strategies for implementing and deploying mmWave massive MIMO systems in-flight cabins, for instance, how to place and distribute access points to enhance coverage and serve quality and the appropriate quantization strategy balancing hardware cost and signal processing quality.
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| 3. |
- Nie, Wei, et al.
(författare)
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NO at low concentration can enhance the formation of highly oxygenated biogenic molecules in the atmosphere
- 2023
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Ingår i: Nature Communications. - Malmö : IVL Svenska Miljöinstitutet AB. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- The interaction between nitrogen monoxide (NO) and organic peroxy radicals (RO2) greatly impacts the formation of highly oxygenated organic molecules (HOM), the key precursors of secondary organic aerosols. It has been thought that HOM production can be significantly suppressed by NO even at low concentrations. Here, we perform dedicated experiments focusing on HOM formation from monoterpenes at low NO concentrations (0 – 82 pptv). We demonstrate that such low NO can enhance HOM production by modulating the RO2 loss and favoring the formation of alkoxy radicals that can continue to autoxidize through isomerization.These insights suggest that HOM yields from typical boreal forest emissions can vary between 2.5%-6.5%, and HOM formation will not be completely inhibited even at high NO concentrations. Our findings challenge the notion that NO monotonically reduces HOM yields by extending the knowledge of RO2-NO interactions to the low-NO regime. This represents a major advance towards an accurate assessment of HOM budgets, especially in low-NO environments, which prevails in the preindustrial atmosphere, pristine areas, and the upper boundary layer.
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