SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "swepub ;pers:(Ottersten Björn 1961)"

Sökning: swepub > Ottersten Björn 1961

  • Resultat 361-370 av 744
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
361.
  • Kisseleff, S., et al. (författare)
  • Random Access-Based Reliable Uplink Communication and Power Transfer Using Dynamic Power Splitting
  • 2020
  • Ingår i: IEEE Transactions on Wireless Communications. - : Institute of Electrical and Electronics Engineers (IEEE). - 1536-1276 .- 1558-2248. ; 19:6, s. 4307-4320
  • Tidskriftsartikel (refereegranskat)abstract
    • Large communication networks, e.g. Internet of Things (IoT), are known to be vulnerable to co-channel interference. One possibility to address this issue is the use of orthogonal multiple access (OMA) techniques. However, due to a potentially very long duty cycle, OMA is not well suited for such schemes. Instead, random medium access (RMA) appears more promising. An RMA scheme is based on transmission of short data packets with random scheduling, which is typically unknown to the receiver. The received signal, which consists of the overlapping packets, can be used for energy harvesting and powering of a relay device. Such an energy harvesting relay may utilize the energy for further information processing and uplink transmission. In this paper, we address the design of a simultaneous information and power transfer scheme based on randomly scheduled packet transmissions and reliable symbol detection. We formulate a prediction problem with the goal to maximize the harvested power for an RMA scenario. In order to solve this problem, we propose a new prediction method, which shows a significant performance improvement compared to the straightforward baseline scheme. Furthermore, we investigate the complexity of the proposed method and its vulnerability to imperfect channel state information. 
  •  
362.
  •  
363.
  • Kisseleff, S., et al. (författare)
  • Reconfigurable Intelligent Surfaces for Smart Cities : Research Challenges and Opportunities
  • 2020
  • Ingår i: IEEE Open Journal of the Communications Society. - : Institute of Electrical and Electronics Engineers (IEEE). - 2644-125X. ; 1, s. 1781-1797
  • Tidskriftsartikel (refereegranskat)abstract
    • The concept of Smart Cities has been introduced as a way to benefit from the digitization of various ecosystems at a city level. To support this concept, future communication networks need to be carefully designed with respect to the city infrastructure and utilization of resources. Recently, the idea of 'smart' environment, which takes advantage of the infrastructure in order to enable better performance of wireless networks, has been proposed. This idea is aligned with the recent advances in design of reconfigurable intelligent surfaces (RISs), which are planar structures with the capability to reflect impinging electromagnetic waves toward preferred directions. Thus, RISs are expected to provide the necessary flexibility for the design of the 'smart' communication environment, which can be optimally shaped to enable cost- A nd energy-efficient signal transmissions where needed. Upon deployment of RISs, the ecosystem of the Smart Cities would become even more controllable and adaptable, which would subsequently ease the implementation of future communication networks in urban areas and boost the interconnection among private households and public services. In this article, we provide our vision on RIS integration into future Smart Cities by pointing out some forward-looking new application scenarios and use cases and by highlighting the potential advantages of RIS deployment. To this end, we identify the most promising research directions and opportunities. The respective design problems are formulated mathematically. Moreover, we focus the discussion on the key enabling aspects for RIS-assisted Smart Cities, which require substantial research efforts such as pilot decontamination, precoding for large multiuser networks, distributed operation and control of RISs. These contributions pave the road to a systematic design of RIS-assisted communication networks for Smart Cities in the years to come.
  •  
364.
  • Kisseleff, Steven, et al. (författare)
  • Reconfigurable Intelligent Surfaces in Challenging Environments : Underwater, Underground, Industrial and Disaster
  • 2021
  • Ingår i: IEEE Access. - : Institute of Electrical and Electronics Engineers (IEEE). - 2169-3536. ; 9, s. 150214-150233
  • Tidskriftsartikel (refereegranskat)abstract
    • Challenging environments comprise a range of scenarios, which share the fact that it is extremely difficult to establish a communication link using conventional technology due to many impairments typically associated with the propagation medium and increased signal scattering. Specifically, underwater and underground media are known to absorb electromagnetic radiation, which heavily affects the overall path loss. Industrial and disaster environments can be viewed as rich scattering environments with corresponding substantial multipath propagation leading to intersymbol interference and deterioration of signal quality. Although the challenges for the design of communication networks, and specifically the Internet of Things (IoT), in such environments are known, there is no common enabler or solution for all these applications. Reconfigurable intelligent surfaces (RISs) have been introduced to improve the signal propagation characteristics by focusing the signal power in the preferred direction, thus making the communication environment’smart’. While the usual application of RIS is related to blockage avoidance, the very same technique can be used to reduce the effect of multipath and even partially compensate the signal absorption via passive beamforming. Due to the beneficial properties of RIS, its use in challenging environments can become the aforementioned enabler and a game changing technology. However, various aspects of RIS deployment and system design need to be addressed in order to fully benefit from this technology. In this paper, we discuss potential use cases, deployment strategies and design aspects for RIS devices in underwater IoT, underground IoT as well as Industry 4.0 and emergency networks. Furthermore, we provide a potential hardware architecture and derive the expected signal quality improvements with increasing number of RIS elements. The numerical results reveal substantial performance gains of up to 20 dB per decade. In addition, novel research challenges to be addressed in this context are described.
  •  
365.
  • Kisseleff, S., et al. (författare)
  • Symbol-Level Precoding with Constellation Rotation in the Finite Block Length Regime
  • 2021
  • Ingår i: IEEE Communications Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 1089-7798 .- 1558-2558.
  • Tidskriftsartikel (refereegranskat)abstract
    • This letter tackles the problem of optimizing the parameters of a symbol-level precoder for downlink multi-antenna multi-user systems in the finite block length regime. Symbol-level precoding (SLP) is a non-linear technique for multi-user wireless networks, which exploits constructive interference among co-channel links. Current SLP designs, however, implicitly assume asymptotically infinite blocks, since they do not take into account that the design rules for finite and especially short blocks might significantly differ. This letter fills this gap by introducing a novel SLP design based on discrete constellation rotations. The rotations are the added degree of freedom that can be optimized for every block to be transmitted, for instance, to save transmit power. Numerical evaluations of the proposed method indicate substantial power savings, which might be over 99% compared to the traditional SLP, at the expense of a single additional pilot symbol per block for constellation de-rotation.
  •  
366.
  •  
367.
  •  
368.
  • Klang, Göran, et al. (författare)
  • Channel Estimation and Interference Rejection for Multichannel Systems
  • 1998
  • Ingår i: Proceedings Asilomar Conference on Signals, Systems & Computers. ; , s. 769-773
  • Konferensbidrag (refereegranskat)abstract
    • A number of schemes for blind channel estimation have been proposed to mitigate the problem of intersymbol (ISI) and co-channel interference (CCI) in mobile communication environments. In many of the proposed schemes no attention is paid to the fact that in most existing and scheduled future systems, training sequences will be available within the transmission protocol of the desired users. In this paper a semi-blind approach utilizing the rich structure inherent in the base station antenna array output and the knowledge of the desired user's training sequence is proposed in order to improve the transmission link performance. In the described approach cancellation of unknown interfering sources is performed based on blind estimation of their corresponding channels allowing the channels of the desired users to be estimated using a conventional training sequence based channel estimation algorithm
  •  
369.
  • Klang, Göran, et al. (författare)
  • Interference Rejection in Systems Employing Transmit Diversity
  • 2002
  • Ingår i: European Signal Processing Conference. - : EUSIPCO. - 2219-5491.
  • Tidskriftsartikel (refereegranskat)abstract
    • Space diversity methods provide excellent means for increasing the robustness against interference and noise in communication systems. This is well known for systems using multiple receive antennas and it holdsforsystems applying transmit diversity as well. In fact, the use of transmit diversity provide two independent means for reducing the impact of interference. Via the diversity gain and via the code rate, both related to the underlying space-time code. In this paper, we are considering the use of space diversity methods in conjunction with interference rejection combining (IRC) to mitigate the impact of interference and noise for interference limited scenarios. Transmit diversity schemes based on space-time block codes (STBC) are assumed. We elucidate the importance of taking into account the spatio-temporal correlation induced by cochannel users employing transmit diversity. A novel space-time IRC (STIRC) scheme is proposed to handle the problem. The STIRC scheme combines the simplicity of conventional IRC while taking the structure of interfering users into account. Simulation examples demonstrate significant gains compared to the use of conventional IRC.
  •  
370.
  • Klang, Göran, et al. (författare)
  • Interference robustness aspects of space-time block code-based transmit diversity
  • 2005
  • Ingår i: IEEE Transactions on Signal Processing. - : IEEE Signal Processing Society. - 1053-587X .- 1941-0476. ; 53:4, s. 1299-1309
  • Tidskriftsartikel (refereegranskat)abstract
    • Transmit diversity, which was initially developed for noise-limited environments, has been promoted as a viable candidate for improving the link quality in both existing and future systems for wireless communication. However, to ensure efficient spectrum utilization, receivers operating within wireless multiuser networks must be robust not only to fading and noise but to interference from other system users as well. This work considers interference robustness aspects when transmit diversity, in the form of space-time block coding, is used in multiuser systems. Properties of the space-time block encoded signals such as code rate, block structure, diversity order, etc., and their implications on detection and interference rejection by means of noise whitening are discussed. To handle the presence of space-time block encoded interference, a space-time processing-based extension of an interference rejection combining algorithm is proposed. Results are presented indicating that transmit diversity based on space-time block codes (STBCs) of the linear dispersion type improve robustness against interference in terms of an increased diversity advantage. This can be achieved either by increasing the number of transmit antennas or by reducing the rate of the code. It is also shown, by analysis and by simulation examples, that the performance improvements obtained by using transmit diversity in multiuser systems may rapidly subside as the signal-to-interference ratio decreases. However, by using the proposed interference rejection scheme tailored to the space-time encoded structure, performance improvements of transmit diversity are also obtained in a multiuser environment.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 361-370 av 744
Typ av publikation
konferensbidrag (405)
tidskriftsartikel (311)
bokkapitel (13)
annan publikation (7)
patent (6)
rapport (1)
visa fler...
proceedings (redaktörskap) (1)
visa färre...
Typ av innehåll
refereegranskat (684)
övrigt vetenskapligt/konstnärligt (53)
populärvet., debatt m.m. (7)
Författare/redaktör
Chatzinotas, S. (191)
Chatzinotas, Symeon (80)
Bengtsson, Mats, 196 ... (54)
Aouada, D. (36)
Sharma, S. K. (35)
visa fler...
Vu, T. X. (35)
Lagunas, E. (30)
Viberg, Mats (24)
Lei, L. (22)
Bhavani Shankar, M. ... (21)
Kristensson, Martin (19)
Gautam, S. (19)
Maleki, S (18)
Jansson, Magnus (18)
Tsinos, C. G. (18)
Mirbach, Bruno (16)
Björnson, Emil, 1983 ... (16)
Jaldén, Joakim, 1976 ... (16)
Lagunas, Eva (15)
Zheng, Gan (15)
Parkvall, Stefan (14)
Aouada, Djamila (13)
Mishra, K. V. (13)
Haqiqatnejad, A. (13)
Alaee-Kerahroodi, M. (12)
Christopoulos, D. (12)
Astély, David (12)
Krivochiza, J. (12)
Grotz, J. (11)
Spano, D. (11)
Stoica, Petre (11)
Shankar, M. R. Bhava ... (11)
Shankar, M. R. B. (11)
Sedighi, S. (10)
Zetterberg, Per (10)
Alodeh, M. (10)
Bergman, Svante, 197 ... (10)
Hammarwall, David (10)
Kayhan, F. (10)
Swindlehurst, Andrew ... (9)
Zhang, Xi (9)
Joroughi, V. (9)
Papadopoulos, K. (9)
Palomar, Daniel P. (9)
Vuppala, S. (9)
Van Chien, Trinh (9)
Sharma, Shree Krishn ... (9)
Huang, Yongming (9)
Dokhanchi, S. H. (9)
visa färre...
Lärosäte
Kungliga Tekniska Högskolan (744)
Linköpings universitet (19)
Uppsala universitet (6)
Chalmers tekniska högskola (2)
Högskolan i Gävle (1)
Språk
Engelska (744)
Forskningsämne (UKÄ/SCB)
Teknik (743)
Naturvetenskap (9)

År

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy