| 1. |
- Fertner, Antoni, et al.
(författare)
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Applications of Backscattering for the Study of Twisted Pair Transmission Lines
- 2018
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480. ; 66:12, s. 5230-5237
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Tidskriftsartikel (refereegranskat)abstract
- The phenomenon of backscattering in copper cables has been recently observed and initially explicated. It can provide promising techniques to address the problem of loop diagnostic and maintenance. The backscattering is analyzed both in frequency and time domains. To demonstrate the practical use of the phenomenon, we estimate certain properties of the loop using wideband, high-frequency $\selevenf(f)$ measurements performed in the laboratory on real cables. The results corroborate the usefulness and accuracy of the investigated method.
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| 2. |
- Fertner, Antoni, et al.
(författare)
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Backscattering in Twisted-Pair Nonhomogeneous Transmission Lines
- 2018
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480. ; 66:6, s. 2674-2682
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Tidskriftsartikel (refereegranskat)abstract
- The development of the communication networks tends gradually toward exploiting higher frequencies, sometimes even reaching the lowest microwave band (P-band). As the signal bandwidth used for transmission over twisted-pairs increases, as recommended by G.fast and other broadband systems, new phenomenon was observed, namely, backscattering. Motivated by the measurements of copper cables in frequency band up to 400 MHz, we propose a novel backscattering model. It may be productively applied to the problem of loop diagnostics. The methods to accurately and reliable determine the relevant transmission-line parameters are sine qua non condition to appropriately exploit the potential of short-to-medium range access lines. In this paper, a recursive formulation of the frequency-domain response of the backscattering is used for a space-time characterization. To confirm the practical use of the finding, we evaluate the properties of a loop using wideband, high-frequency S₁₁ measurements of the real cables. These laboratory results confirm the effectiveness and accuracy of the proposed method.
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| 3. |
- Brito, Flavio, et al.
(författare)
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A network architecture for scalable end-to-end management of reusable AI-based applications
- 2023
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Ingår i: Proceedings of the 14th International Conference on Network of the Future, NoF 2023. - 9798350338072 ; , s. 98-102
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Konferensbidrag (refereegranskat)abstract
- Artificial intelligence (AI) is a key enabler for future 6G networks. Currently, related architecture works propose AI-based applications and network services that are dedicated to specific tasks (e.g., improving the performance of RAN with AI). These proposed architectures offer a unique way to collect data, process it, and extract features from data for each AI-based application. However, this dedicated approach creates AI-silos that hinder the integration of AI in the networks. In other words, such AI-silos create a set of AI-models and data for AI-based applications that only work within a single dedicated task. This single-task approach limits the end-to-end integration of AI in the networks. In this work, we propose a network architecture to deploy AI-based applications, at different network domains, that prevents AI-silos by offering reusable data and models to ensure scalable deployments. We describe the architecture, provide workflows for the end-to-end management of AI-based applications, and show the viability of the architecture through multiple use cases.
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| 4. |
- Huang, Yezi, et al.
(författare)
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Functional Split of Zero-Forcing Based Massive MIMO for Fronthaul Load Reduction
- 2018
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Ingår i: IEEE Access. - 2169-3536. ; 6, s. 6350-6359
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Tidskriftsartikel (refereegranskat)abstract
- The evolution towards centralized radio access network (C-RAN) for 5G is driven by the need for improved network performance and reduced total-cost-of-ownership (TCO). In CRAN, physically separated remote radio units (RRUs) and baseband units (BBUs) are connected via fronthaul (FH) links, which are capacity constrained. When base-station antennas are upgraded to support massive MIMO techniques, an intra PHY split between RRU and BBU becomes favorable to avoid the dramatic rate growth on the FH links. In this paper, we present a new uplink functional split alternative that decomposes the massive MIMO processing, on the basis of zero-forcing (ZF) equalization, into two phases: dimension-reduction phase and interference cancellation phase, which are implemented in RRU and BBU respectively. Compared with the traditional C-RAN architecture having all baseband processing in the BBU, the new scheme largely alleviates the FH load by reducing the number of FH streams to be equal to the number of MIMO user layers. Compared with an existing split that places all MIMO processing in RRU, the new scheme reduces the RRU complexity without compromising the post-processing performances.
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| 5. |
- Statovci, Driton, et al.
(författare)
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Network Modeling and Performance Evaluation for G.fast
- 2021
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Ingår i: IEEE Access. - 2169-3536. ; 9, s. 164026-164036
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Tidskriftsartikel (refereegranskat)abstract
- G.fast is a gap-bridging broadband technology on the way to a fully optical access network. G.fast is deployed in hybrid fiber-copper access networks and aiming to offer ubiquitous low-cost and high-speed broadband. For network operators, it is crucial to determine the location from where to deploy G.fast, the expected network coverage, and the expected bit rates. In this paper, we perform network modeling and statistically assess the performance of G.fast based on actual network data in four geotype classes: urban, suburban, dense rural, and sparse rural. For each class, we have collected the network data in the field with a substantial number of twisted-pair lines in Austria. Statistical analysis of loop lengths indicates that to improve the network coverage, the G.fast should be deployed in urban and suburban areas from the so-called remote node, whereas in rural areas from the last distribution point. Under such a deployment rule, the analysis by means of empirical complementary cumulative distribution functions shows a good network coverage for all network classes. Furthermore, the simulation results indicate a significant influence of cable types. Consequently, for the benefit of the cable community, we share measurements of 695 twisted-pairs of cable types relevant for G.fast deployment commonly found in the Austrian network.
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| 6. |
- Zhang, Chao, et al.
(författare)
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A Virtualized LoRa Testbed and Experimental Results for Resource Pooling
- 2021
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Ingår i: 7th IEEE World Forum on Internet of Things, WF-IoT 2021. - 9781665444316 ; , s. 871-876
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Konferensbidrag (refereegranskat)abstract
- Traditional network architecture design of Low Power Wide Area Networks (LPWAN) is incapable of dynamically scaling resources based on the served traffic and requires manual procedures for network capacity upgrades. Today's over-provisioning approach based on proprietary hardware (HW) would not be cost and energy efficient to cope with the ever-increasing scale of Internet of Things (IoT) devices in future. The concept of virtualized radio access network (vRAN) by softwarizing and virtualizing communication stacks to a cloud environment is seen as a potential solution to provide web-scale scalability with the benefit of automation and resource pooling, which would significantly increase the resource utilization efficiency. In this work, we developed a LoRa-based testbed to investigate the resource pooling perspective for virtualized physical layer (PHY) functions in a Cloud environment. The testbed is first experimentally validated by comparing the single-cell emulation results and the test results with real LoRa devices. The results show that the testbed can generate the same traffic pattern as real LoRa devices, where two cases show similar resource usages. Then the multi-cell experiments show that one PHY function instance can serve many full-traffic LoRa cells, which showcases a great potential of resource pooling for LoRa networks.
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