| 1. |
- Alegria, Juan Vidal, et al.
(författare)
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Decentralized equalizer construction for large intelligent surfaces
- 2019
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Ingår i: 2019 IEEE 90th Vehicular Technology Conference, VTC 2019 Fall - Proceedings. - 1550-2252. - 9781728112206 ; 2019-September
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Konferensbidrag (refereegranskat)abstract
- In this paper we present fully decentralized methods for calculating an approximate zero- forzing (ZF) equalizer in a large intelligent surface (LIS). A LIS is intended for wireless communication and facilitates unprecedented MU- MIMO performance, far superior to that of Massive MIMO. Antenna modules in the grid connect to their neighbors to exchange messages of information needed for interference cancellation in a fully- decentralized fashion, making the system scalable. By a careful design of how the messages are routed, we show that the proposed method is able to cancel inter-user interference sufficiently well without any centralized coordination, opening the door for the realization of this type of structures.
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| 2. |
- Chen, Jingjing, 1982, et al.
(författare)
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Demonstration of analog millimeter-wave fronthaul for 64-QAM LTE transmission
- 2015
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Ingår i: IEEE Vehicular Technology Conference. - 1550-2252.
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Konferensbidrag (refereegranskat)abstract
- Centralized baseband architecture is believed to be cost efficient and to offer high network performance. The fronthaul network, connecting the centralized baseband to distributed remote radios, requires high capacity and low latency transport links, due to the stringent specifications of the data interface, known as common public radio interface (CPRI). Today, fronthaul links are mostly based on digital CPRI over fibers, although it is possible to realize CPRI over wireless technology with the drawback of poor bandwidth efficiency. In this paper, we propose an analog wireless fronthaul concept to enable bandwidth efficient and scalable fronthaul networks. The basic idea is to transport narrow band analog radio signals over millimeter-wave bands instead of multi-gigabit digital signals. The phase and frequency impairments introduced by high frequency carriers are effectively reduced using an analog pilot-based mitigation technique. As a proof-of-concept demonstration, an analog fronthaul link is implemented, and the link performance is verified for 20 MHz 64-QAM LTE transmission over 70/80 GHz (E-band). The measured error vector magnitude (EVM) is about 3% with 10% pilot bandwidth overhead.
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| 3. |
- Cinque, Elena, et al.
(författare)
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Toward a Standard-Compliant Implementation for Consensus Algorithms in Vehicular Networks
- 2018
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Ingår i: IEEE Vehicular Technology Conference. - 1550-2252. ; 2018-August
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Konferensbidrag (refereegranskat)abstract
- Cooperative Intelligent Transport System (C-ITS) applications require a continuous exchange of information between road users and roadside infrastructures. In this regard, distributed consensus algorithms can play an essential role in the definition of the information exchange rules between an ITS station and its neighbors. Although the consensus approach for networked systems is well-established, the efficiency of consensus methods under real-world vehicular communication constraints is largely unknown. This paper provides an ITS standard-compliant framework for analysis of consensus algorithms in vehicular networks with an emphasis on the role of robustness to changes in network topology in highly dynamic and dense environments. Our simulations reveal that in regular traffic conditions, the implemented consensus algorithm is able to achieve good performances in terms of both convergence time and needed consensus iterations. However, numerical results demonstrate that under dense and high-mobility traffic conditions the frequent exchange of large amounts of range information increases the Channel Busy Ratio (CBR) of the vehicular network and reduces the effectiveness of the algorithm as well.
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| 4. |
- Fang, Chao, 1991, et al.
(författare)
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HARQ in Poisson Point Process-based Heterogeneous Networks
- 2015
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Ingår i: IEEE Vehicular Technology Conference. - 1550-2252. - 9781479980888 ; 2015
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Konferensbidrag (refereegranskat)abstract
- Hybrid automatic repeat request (HARQ) plays animportant role in improving the transmission efficiency and the robustness of wireless networks. Considering K-tier heterogeneous networks (HetNets) and modelling the locations of the base stations (BSs) as a homogeneous Poisson point process (PPP), this paper investigates the performance of HetNets implementing HARQ. We give closed-form expressions for the coverage probability and the per-user throughput with HARQ and show that using HARQ can indeed improve the coverage probability. However, depending on the channel conditions, the per-userthroughput of the HetNets may decrease by the implementation of HARQ. Furthermore, we show that the small cell density has negligible effect on the coverage probability and per-user throughput, and the per-user throughput may increase with the small cell path loss.
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| 5. |
- Hoang, Le-Nam, 1984-, et al.
(författare)
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Low Complexity Algorithm for Efficient Relay Assignment in Unicast/Broadcast Wireless Networks
- 2017
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Ingår i: 2017 IEEE 85th Vehicular Technology Conference (VTC Spring). - : IEEE. - 9781509059324 - 9781509059331 ; June
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Konferensbidrag (refereegranskat)abstract
- Using relayers in wireless networks enables higher throughput, increased reliability or reduced delay. However, when building networks using commercially available hardware, concurrent transmissions by multiple relayers are generally not possible. Instead one specific relayer needs to be assigned for each transmission instant. If the decision regarding which relayer to assign, i.e., which relayer that has the best opportunity to successfully deliver the packet, can be taken online, just before the transmission is to take place, much can be gained. This is particularly the case in mobile networks, as a frequently changing network topology considerably affects the choice of a suitable relayer. To this end, this paper addresses the problem of online relay assignment by developing a low-complexity algorithm highly likely to find the optimal combination of relaying nodes that minimizes the resulting error probability at the targeted receiver(s) using a mix of simulated annealing and ant colony algorithms, such that relay assignments can be made online also in large networks. The algorithm differs from existing works in that it considers both unicast as well as broadcast and assumes that all nodes can overhear each other, as opposed to separating source nodes, relay nodes and destination nodes into three disjoint sets, which is generally not the case in most wireless networks.
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| 6. |
- Johanson, Matthias, et al.
(författare)
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Joint subjective and objective data capture and analytics for automotive applications
- 2017
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Ingår i: IEEE Vehicular Technology Conference. - 1550-2252. - 9781509059355
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Konferensbidrag (refereegranskat)abstract
- In this paper we describe a novel technological framework for capture and analysis of both objective measurement data and subjective user experience data for automotive applications. We also investigate how the framework can be extended to address privacy issues by enforcing a rigorous privacy model called differential privacy. The system under development integrates a telematics system with a smartphone app service architecture and a data-driven analytics framework. The hypothesis is that the framework will improve the opportunities of conducting large scale user trials of automotive functions and services, while improving the quality of collected data. To achieve this, a number of challenges are addressed in the paper, including how to design the subjective data capture mechanisms to be both simple to use yet powerful, how to correlate subjective data with objective measurement data, and how to protect the privacy of users.
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| 7. |
- Lautenbach, Aljoscha, 1985, et al.
(författare)
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A Preliminary Security Assessment of 5G V2X
- 2019
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Ingår i: IEEE Vehicular Technology Conference. - 1550-2252. ; 2019-April
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Konferensbidrag (refereegranskat)abstract
- Research on intelligent transport systems (ITS) for improved traffic safety and efficiency has reached a high level of maturity and first applications will hit the market in 2019. Since 2004, the wireless standard 802.11p has been developed specifically for ITS services. Since then new telecommunication standards have been devised, and the new 5G telecommunication standard is nearing completion. Due to its technological advantages such as higher speeds and reliability, it is being considered to be used for ITS services.The new radio technology “NewRadio (NR)”, which is being developed as part of 5G, can complement or replace 802.11p in V2X applications. While there has been some work to compare 802.11p and 5G New Radio in terms of performance and applicability for safety-critical use cases, little work has been done to investigate the implications for security. In this paper, we provide an overview of the security requirements of known ETSI ITS use cases, and based on those use cases we compare and assess the security implications of replacing 802.11p with cellular V2X. We find that due to the use of millimeter waves, beamforming and massive MIMO, there will be an implicit improvement for confidentiality and privacy, and it may also be possible to shorten authentication procedures in certain cases. When a fully network-assisted C-V2X mode is chosen, it is also possible to outsource several of the ITS security requirements to the cellular network.
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| 8. |
- Mazloum, Nafiseh Seyed, et al.
(författare)
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Energy savings using wake-up receivers - An analysis of optimal designs
- 2019
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Ingår i: 2019 IEEE 90th Vehicular Technology Conference, VTC 2019 Fall - Proceedings. - 1550-2252. - 9781728112206 ; 2019-September
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Konferensbidrag (refereegranskat)abstract
- With increasing number of wirelessly connected devices having limited energy resources, energy efficient solutions become more and more important. Many studies have addressed schemes where low-power wake-up receivers are used to improve energy efficiency in networks with low traffic intensity (per node) and demands on availability. One such scheme is the duty-cycled wake-up receiver medium access (DCW-MAC) scheme, for which we have detailed understanding of achievable energy savings. In this paper we combine these with recent bounds on the characteristics of optimal low-power receiver designs. What we find is that network energy savings are always achievable with optimally designed wake-up receivers. Moreover, potential network energy savings increase as wake-up receiver power consumption decreases, despite the associated degradation in performance. The lowest network energy consumption, for this type of network, is reached for wake-up receivers pushed to the limit of functioning.
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| 9. |
- Mokhtari, Zahra, et al.
(författare)
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Iterative Channel and CFO Estimation for SC-FDE and OFDM based Massive MIMO Systems
- 2019
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Ingår i: IEEE Vehicular Technology Conference. - 1550-2252. - 9781728112176 ; 2019-April
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Konferensbidrag (refereegranskat)abstract
- Low complexity and spectral efficient carrier frequency offset (CFO) estimation in massive multiple input multiple output (MIMO) systems is a critical problem. Therefore, in this paper we propose a low complexity CFO estimation technique for single carrier frequency domain equalization (SC-FDE) and orthogonal frequency division multiplexing (OFDM) based Massive MIMO systems. In this technique, to increase the spectral efficiency, we use the pilots sent for channel estimation to estimate both the CFO and the channel, iteratively. Our analysis show that our proposed technique has better performance and lower complexity than previous techniques which utilize one pilot block for both CFO and channel estimation in massive MIMO systems.
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| 10. |
- Nelson, Boel, 1991, et al.
(författare)
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Introducing Differential Privacy to the Automotive Domain: Opportunities and Challenges
- 2017
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Ingår i: IEEE Vehicular Technology Conference. - 1550-2252. ; 2017-September, s. 1-7
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Konferensbidrag (refereegranskat)abstract
- Privacy research is attracting increasingly more attention, especially with the upcoming general data protection regulation (GDPR) which will impose stricter rules on storing and managing personally identifiable information (PII) in Europe. For vehicle manufacturers, gathering data from connected vehicles presents new analytic opportunities, but if the data also contains PII, the data comes at a higher price when it must either be properly de-identified or gathered with contracted consent from the drivers. One option is to establish contracts with every driver, but the more tempting alternative is to simply de-identify data before it is gathered, to avoid handling PII altogether. However, several real-world examples have previously shown cases where re-identification of supposedly anonymized data was possible, and it has also been pointed out that PII has no technical meaning. Additionally, in some cases the manufacturer might want to release statistics either publicly or to an original equipment manufacturer (OEM). Given the challenges with properly de-identifying data, structured methods for performing de-identification should be used, rather than arbitrary removal of attributes believed to be sensitive. A promising research area to help mitigate the re-identification problem is differential privacy, a privacy model that unlike most privacy models gives mathematically rigorous privacy guarantees. Although the research interest is large, the amount of real-world implementations is still small, since understanding differential privacy and being able to implement it correctly is not trivial. Therefore, in this position paper, we set out to answer the questions of how and when to use differential privacy in the automotive industry, in order to bridge the gap between theory and practice. Furthermore, we elaborate on the challenges of using differential privacy in the automotive industry, and conclude with our recommendations for moving forward.
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