| 1. |
- Jahandideh, Mojtaba, et al.
(författare)
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Low Complexity Sparse Channel Estimation for Wideband mmWave Systems: Multi-Stage Approach
- 2019
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Ingår i: 2019 IEEE WIRELESS COMMUNICATIONS AND NETWORKING CONFERENCE (WCNC). - : IEEE. - 9781538676462
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Konferensbidrag (refereegranskat)abstract
- We consider the problem of channel estimation in hybrid transceiver architectures operating in millimeter wave (mmWave) band. Due to the dynamic features of the environment and the sensitivity of mmWave bands to blockage and deafness, it is important to estimate mmWave channels with a low complexity and high performance algorithm. In this regard, we exploit the sparse structure of the frequency-selective mmWave channels and formulate the channel estimation problem as a sparse signal reconstruction in frequency domain. In order to solve the estimation problem, we propose a multi-stage based low complexity algorithm. Simulation results show that the proposed algorithm significantly reduces the computational complexity while preserving the quality of the estimation.
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| 2. |
- Joshi, Satya Krishna, et al.
(författare)
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Weighted Sum-Rate Maximization for MISO Downlink Cellular Networks via Branch and Bound
- 2012
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Ingår i: IEEE Transactions on Signal Processing. - 1053-587X .- 1941-0476. ; 60:4, s. 2090-2095
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Tidskriftsartikel (refereegranskat)abstract
- The problem of weighted sum-rate maximization (WSRMax) in multicell downlink multiple-input single-output (MISO) systems is considered. The problem is known to be NP-hard. We propose a method, based on branch and bound technique, which solves globally the nonconvex WSRMax problem with an optimality certificate. Specifically, the algorithm computes a sequence of asymptotically tight upper and lower bounds and it terminates when the difference between them falls below a pre-specified tolerance. Novel bounding techniques via conic optimization are introduced and their efficiency is demonstrated by numerical simulations. The proposed method can be used to provide performance benchmarks by back-substituting it into many existing network design problems which relies on WSRMax problem. The method proposed here can be easily extended to maximize any system performance metric that can be expressed as a Lipschitz continuous and increasing function of signal-to-interference-plus-noise ratio.
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| 3. |
- Pirinen, Pekka, et al.
(författare)
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Wireless Connectivity for Remote and Arctic Areas – Food for Thought
- 2019
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Ingår i: ISWCS 2019. - : IEEE. ; , s. 43-47
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper addresses various aspects that should be considered to improve the digital inclusion of remote, and specifically arctic areas, so that the geographical location would play a lesser role in equality among the people. To this end, technological challenges and potential solutions are discussed. They are further elaborated by three examples that have different architectural use case specific challenges for remote area wireless connectivity. The active role of society is seen pivotal alongside with the technological solutions to make this happen.
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| 4. |
- Uusitalo, Mikko A., et al.
(författare)
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6G Vision, Value, Use Cases and Technologies from European 6G Flagship Project Hexa-X
- 2021
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Ingår i: IEEE Access. - 2169-3536 .- 2169-3536. ; 9, s. 160004-160020
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Tidskriftsartikel (refereegranskat)abstract
- While 5G is being deployed and the economy and society begin to reap the associated benefits, the research and development community starts to focus on the next, 6th Generation (6G) of wireless communications. Although there are papers available in the literature on visions, requirements and technical enablers for 6G from various academic perspectives, there is a lack of joint industry and academic work towards 6G. In this paper a consolidated view on vision, values, use cases and key enabling technologies from leading industry stakeholders and academia is presented. The authors represent the mobile communications ecosystem with competences spanning hardware, link layer and networking aspects, as well as standardization and regulation. The second contribution of the paper is revisiting and analyzing the key concurrent initiatives on 6G. A third contribution of the paper is the identification and justification of six key 6G research challenges: (i) “connecting”, in the sense of empowering, exploiting and governing, intelligence; (ii) realizing a network of networks, i.e., leveraging on existing networks and investments, while reinventing roles and protocols where needed; (iii) delivering extreme experiences, when/where needed; (iv) (environmental, economic, social) sustainability to address the major challenges of current societies; (v) trustworthiness as an ingrained fundamental design principle; (vi) supporting cost-effective global service coverage. A fourth contribution is a comprehensive specification of a concrete first-set of industry and academia jointly defined use cases for 6G, e.g., massive twinning, cooperative robots, immersive telepresence, and others. Finally, the anticipated evolutions in the radio, network and management/orchestration domains are discussed.
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| 5. |
- Uusitalo, Mikko A., et al.
(författare)
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Hexa-X: The european 6G flagship project
- 2021
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Ingår i: 2021 Joint European Conference on Networks and Communications and 6G Summit, EuCNC/6G Summit 2021. ; , s. 580-585
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Konferensbidrag (refereegranskat)abstract
- Hexa-X will pave the way to the next generation of wireless networks (Hexa) by explorative research (X). The Hexa-X vision is to connect human, physical, and digital worlds with a fabric of sixth generation (6G) key enablers. The vision is driven by the ambition to contribute to objectives of growth, global sustainability, trustworthiness, and digital inclusion. Key 6G value indicators and use cases are defined against the background of technology push, society and industry pull as well as objectives of technology sovereignty. Key areas of research have been formulated accordingly to include connecting intelligence, network of networks, sustainability, global service coverage, extreme experience, and trustworthiness. Critical technology enablers for 6G are developed in the project including, sub-THz transceiver technologies, accurate stand-alone positioning and radio-based imaging, improved radio performance, artificial intelligence (AI) / machine learning (ML) inspired radio access network (RAN) technologies, future network architectures and special purpose solutions including future ultra-reliable low-latency communication (URLLC) schemes. Besides technology enablers, early trials will be carried out to help assess viability and performance aspects of the key technology enablers. The 6G Hexa-X project is integral part of European and global research effort to help define the best possible next generation of networks.
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