| 1. |
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| 2. |
- Haneda, Katsuyuki, et al.
(författare)
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Comparison of angular and delay spreads between channel measurements and the COST channel model
- 2010
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Ingår i: ; , s. 477-480
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Konferensbidrag (refereegranskat)abstract
- The COST2100 channel model is a reference channel model which provides dynamic multiple-input multiple-output channel responses for radio system simulations. In this paper, channels created by the COST2100 model were compared to channel measurements in order to understand behaviours of the model. Model parameters of the COST2100 model were derived by dynamic double-directional channel measurements with which the channel realizations from the COST2100 model were compared. Delay and angular spreads were used as a simple but important metric for the comparison. Despite a fundamental difference that the COST2100 model is a geometry- based stochastic model while the channel measurements are ob- tained in deterministic environments, the comparison revealed an acceptable level of agreement for practical channel simulations.
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| 3. |
- Haneda, Katsuyuki, et al.
(författare)
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Comparison of delay and angular spreads between channel measurements and the COST2100 channel model
- 2010
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Ingår i: 2010 Loughborough Antennas and Propagation Conference, LAPC 2010. - 9781424473052 ; , s. 477-480
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Konferensbidrag (refereegranskat)abstract
- The COST2100 channel model is a reference channel model which provides dynamic multiple-input multiple-output channel responses for radio system simulations. In this paper, channels created by the COST2100 model were compared to channel measurements in order to understand behaviours of the model. Model parameters of the COST2100 model were derived by dynamic double-directional channel measurements with which the channel realizations from the COST2100 model were compared. Delay and angular spreads were used as a simple but important metric for the comparison. Despite a fundamental difference that the COST2100 model is a geometry-based stochastic model while the channel measurements are obtained in deterministic environments, the comparison revealed an acceptable level of agreement for practical channel simulations
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| 4. |
- Haneda, Katsuyuki, et al.
(författare)
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Measurement of loop-back interference channels for outdoor-to-Indoor full-duplex radio relays
- 2010
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Ingår i: Proceedings of the Fourth European Conference on Antennas and Propagation. - 9788476534724 - 9781424464319
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Konferensbidrag (refereegranskat)abstract
- A full-duplex relay enhances the end-to-end spectral efficiency compared to a half-duplex relay, provided that the loop-back interference at relays is managed well. In order to study the feasibility of the full-duplex relay, it is crucial to measure and model the loop-back interference channels. This paper presents a measurement campaign of these channels for outdoor-to-indoor communications. A compact relay antenna was developed to serve as a signal repeater between outdoor base stations and indoor users, and was used for the loop-back interference channel measurement. Measurement results revealed that the mean interference level was -48 dB in the compact relay antenna, and it could be further reduced by placing the outdoor and indoor antennas in a different position referred to as a separate relay. Combined with an appropriate countermeasure to reduce the interference level, such as an interference canceller, the full-duplex operation of indoor compact relay terminal was found to be feasible.
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| 5. |
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| 6. |
- Jalden, Niklas, 1978-
(författare)
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Analysis and Modelling of Joint ChannelProperties from Multi-site, Multi-Antenna RadioMeasurements
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Future wireless communication systems will utilize the spatialproperties of the wireless channel to improve the spectralefficiency and thus increase capacity. This is realized bydeploying multiple antennas at both the transmitter and receiver.Development and analysis of communication systems utilizing thespatial properties of the channel requires channel models thatproperly reflect these characteristics. Due to the unpredictable nature of the wireless channel, a commonapproach is to model its effects statistically. A few largeworld-wide cooperations, like the third generation partnershipproject (3GPP) or wireless world initiative new radio (WINNER)project, have developed channel models intended for reference andstandardization use. These models are partly based on some bulkparameters that describe the characteristics of the channel overlarger areas of several wavelengths. Such parameters includeshadow fading, angle spread, and delay spread, among others, andare within the WINNER project called large-scale (LS) parameters.In the spatial channel model (SCM) and the WINNER model, theselarge-scale parameters are, however, assumed independent betweenseparate links, i.e., between channels modelling the propagationbetween one mobile and several base stations, or between one basestation and several mobiles. Such assumptions may be valid forsingle-link, singe-cell systems, where each communication link issufficiently separated in either time or frequency. In practice,dependencies between parameters describing separate wirelesschannels is expected. Future systems will allow a dense frequencyreuse, and results from system evaluations based on models withindependent links may be inaccurate. Examples of this may be insystems that exploit the spatial nature of the channel, likemulti-user scheduling using a single carrier, or macro-diversitysystems deploying several base stations. Therefore, it isimportant to analyze multi-node measurements in order to extractand characterize this channel dependence. This thesis focuses on representing the wireless channelstatistically. Through unique multi-site channel measurements andanalysis, key parameters describing the channel namely shadowfading, delay spread and angle spread at both the base station andthe mobile station are extracted. For these parameters, the firstand the second order statistics are derived, and plausibledistributions and models are proposed. Further, the spatial andcorrelation properties of these parameters are analyzed. Moreover,a study highlighting the effect of the independent channelassumption is given, showing the importance of modelling thespatial dependence between the LS parameters when analyzingsystems that utilize the channel's spatial properties.Incorporating the models and correlation properties found hereinfor the LS parameters results in channel models appropriate formulti-node communication analysis and evaluation.
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| 7. |
- Koivunen, Jukka, et al.
(författare)
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Dynamic multi-link indoor MIMO measurements at 5.3 GHz.
- 2007
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Ingår i: Proc 2nd European Conference on Antennas and Propagation (EuCAP 2007).
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Konferensbidrag (refereegranskat)abstract
- A dynamic multi-link MIMO channel indoor measurement campaign at 5.3 GHz is presented in this paper. The system setup is described and capacity with interference (with and without power control) results based on the dynamic multilink MIMO measurements are shown, and we experience a strong correlation between the relative capacity and SIR. Furthermore, an interference suppression metric is introduced and pathloss exponents and delay spreads are also presented, when moving from a typical office corridor to a large entrance hall at the premises of Lund University, Sweden.
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| 8. |
- Kolmonen, Veli-Matti, et al.
(författare)
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A dual-link capacity analysis of measured time-variant radio indoor channels
- 2010
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Ingår i: 2010 IEEE 71st Vehicular Technology Conference. - 9781424425181
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Konferensbidrag (refereegranskat)abstract
- There has been extensive research about single link multiple-input multiple-output (MIMO) channels, both simulated and measured, but only few studies have targeted multilink analysis with measured channel data. Hence, in this paper, we analyze the influence of spatial separation of user terminals and the human shadowing effect on the MIMO capacity and to the signal to interference ratio (SIR) in a time-variant dual-link scenario. The paper analyses the dual-link channel capacity based on simulations as well as measurements conducted using dynamic dual-link dual-polarized wideband MIMO channel sounder in an indoor office environment, and compare the results to the singlelink capacity. Here the analysis is restricted to 4 x 4 MIMO links. The following conclusions have been obtained from the analyses: 1) Compared to the single link case, the dual-link channel capacity is more affected by the SIR than the spatial separation of the users. 2) The human shadowing introduced variations of SIR up to ±10 dB, causing large fluctuations in the dual-link capacity.
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| 9. |
- Kolmonen, Veli-Matti, et al.
(författare)
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A dynamic dual-link wideband MIMO channel sounder for 5.3 GHz
- 2010
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456. ; 59:4, s. 873-883
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Tidskriftsartikel (refereegranskat)abstract
- Abstract in UndeterminedIn this paper, we present and evaluate the performance of a dynamic dual-link wideband multiple-input-multiple-output ( MIMO) channel sounder. The channel sounder can simultaneously measure two wideband dual-polarized links, each with a MIMO matrix size of 30 x 30 and 30 x 32. Multi-link MIMO systems, including multiuser and cooperative MIMO, are essential parts of future high-throughput wireless local area networks and fourth-generation cellular systems. To fully understand such systems, the dynamic characteristics of multilink MIMO channels have to be measured. In this paper, we present a channel sounder that enables such measurements, including double-directional parameter estimation possibility for both links. The presented dual-link MIMO channel sounder does not suffer from the deficiencies of previous "virtual multiuser" measurement systems. Furthermore, system analysis and sample results from a measurement campaign with this channel sounder at 5.3 GHz in an indoor office environment are presented.
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| 10. |
- Kolmonen, Veli-Matti, et al.
(författare)
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Measurement-based evaluation of interlink correlation for indoor multi-user MIMO Channels
- 2010
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Ingår i: IEEE Antennas and Wireless Propagation Letters. - 1548-5757. ; 9, s. 311-314
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Tidskriftsartikel (refereegranskat)abstract
- Abstract in UndeterminedThe properties of the single-link multiple-input-multiple- output (MIMO) propagation channels have been analyzed in many studies based on extensive propagation measurements. In this letter, we extend the measurement-based analysis to dual-link MIMO propagation channels. Here, we examine interlink correlation by evaluating the correlation of eigenvectors obtained from multiple MIMO links. We also investigated how the physical propagation phenomena produced the interlink correlation. Results indicate that interlink correlation may exist. Sometimes it is found to be very high also for far separated receive units, depending on similarity of dominant propagation mechanisms between multiple MIMO links and also on antenna array properties.
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| 11. |
- Liu, Lingfeng, et al.
(författare)
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The COST 2100 MIMO Channel Model
- 2012
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Ingår i: IEEE Wireless Communications. - 1536-1284. ; 19:6, s. 92-99
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Tidskriftsartikel (refereegranskat)abstract
- The COST 2100 channel model is a geometry-based stochastic channel model (GSCM) that can reproduce the stochastic properties of multi-link Multiple-Input Mulitple-Output (MIMO) channels over time, frequency and space. By contrast to other popular GSCMs, the COST 2100 approach is generic and flexible, making it suitable to model multi-user or distributed MIMO scenarios. In this paper a concise overview of the COST 2100 channel model is presented. Main concepts are described, together with useful implementation guidelines. Recent developments, including dense multipath components, polarization and multi-link aspects are also discussed.
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| 12. |
- Marques Duarte da Paz, Ana Marta
(författare)
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Water content measurement in woody biomass : using dielectric constant at radio frequencies
- 2008
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The will for replacement of fossil fuels increased the use of woody biomass as fuel in heating and power plants. An important parameter for the use woody biomass as fuel is the water content of biomass as it influences the heating value and thereby the combustion control and pricing. Currently, water content is determined using the gravimetric method by drying samples in an oven. This method is neither fast nor representative, as the water content can vary largely in different parts of the container which raised the need to develop sensors that are able to measure water content of biomass on-line and in a representative way.This thesis presents results from studies on the measurement of water content of woody biomass with radio frequency. Included are the study on the influence of temperature in the measurements, the use of dielectric mixing models to explain the dielectric behavior of woody biomass and the application of the measurement principle to full-scale. It was found that varying temperature between 1 and 62 °C did not influence the prediction of water content in biomass. It was possible to explain the behavior of the dielectric constant of woody biomass with a model with physical basis using empirically obtained parameters. Application of the principle to full-scale had positive results but larger prediction error than laboratory-scale measurements.
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| 13. |
- Mowlér, Marc, 1979-
(författare)
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On Reconfigurable MEMS Antennas and Coupling Matrix Estimation
- 2006
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, two different topics are treated related to wireless communication. Part I presents three different reconfigurable MEMS integrated antennas for MIMO applications. Simulation and measurement results are presented along with brief discussions on the topic of antenna selection with reconfigurable antenna elements. Part II presents an estimator for the coupling matrix of an antenna array with two slightly different approaches. CRB is derived and discussed in terms of parameter cost.
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| 14. |
- Otterskog, Magnus, 1972-
(författare)
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Propagation environment modeling using scattered field chamber
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis covers the development of the Reverberation Chamber as a measurement tool for cell phone tests in electronic production. It also covers the development of the Scattered Field Chamber as a measurement tool for simulations of real propagation environments. The first part is a more ”general knowledge about Reverberation Chambers”-part that covers some important phenomena like unstirred power and position dependence that might occour in a small Reverberation Chamber used for cell phone tests. Knowing how to deal with these phenomenas, give the possibility to use the chamber as a measurement tool for production tests even though it is too complex for a simple test of the antenna function. The second part shows how to alter some important propagation parameters inside the chamber to fit some real world propagation environments. The 3D plane wave distribution, the polarization and the amplitude statistics of the plane waves are all altered with simple techniques that are implementable all together. A small, shielded anechoic box with apertures is used to control 3D plane wave distribution and polarization. Antennas that introduce unstirred power in the chamber are used to control the statistics.
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| 15. |
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| 16. |
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| 17. |
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| 18. |
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| 19. |
- Poutanen, Juho, et al.
(författare)
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Multi-link MIMO channel modeling using geometry-based approach
- 2012
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Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 60:2, s. 587-596
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Tidskriftsartikel (refereegranskat)abstract
- Geometry-based stochastic channel models (GSCMs) are extended to support multi-link simulations by applying the concept of common clusters. This novel approach aims to control the correlation between different links, inter-link correlation, by adjusting the amount of power simultaneously propagating via the same clusters in the different links. The behavior of common clusters is analyzed based on dual-link channel measurements, and a multi-link GSCM is developed based on common clusters. In addition, the effects that the common clusters have on inter-link correlation and on sum rate capacity are investigated based on simulations. Finally, comparison between simulations and measurements is done in order to indicate the validity of the proposed multi-link GSCM.
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| 20. |
- Poutanen, Juho, et al.
(författare)
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Parameterization of the COST 2100 MIMO channel model in indoor scenarios
- 2011
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Ingår i: [Host publication title missing]. - 9781457702501 ; , s. 3606-3610
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Konferensbidrag (refereegranskat)abstract
- Abstract in Undetermined The COST 2100 MIMO channel model is the latest evolution of the geometry-based stochastic channel models developed by the COST actions. This paper provides a full parameterization of the COST 2100 channel model in four indoor scenarios based on channel measurements conducted in two different buildings. In addition to the parameter values, the meaning and extraction method of each parameter are explained.
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| 21. |
- Poutanen, Juho, et al.
(författare)
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Propagation Characteristics of Dense Multipath Components
- 2010
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Ingår i: IEEE Antennas and Wireless Propagation Letters. - 1548-5757. ; 9, s. 791-794
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Tidskriftsartikel (refereegranskat)abstract
- The dense multipath components (DMC) represent the part of the radio channel that cannot be characterized by a superposition of distinct plane waves, i.e., the specular components (SC). In this letter, the propagation characteristics of the DMC are analyzed in indoor environments from two perspectives. First, the proportion of DMC in the total power is studied as a function of the distance between the transmitter (TX) and receiver (RX). Second, the characteristics of the DMC and SC are compared in angular and delay domains. The measurement results show that the amount of DMC in the total power increases as the TX-RX distance increases in both line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios. In addition, it is shown that the power of the DMC is concentrated around the same angles and delays as the SC.
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| 22. |
- Poutanen, Juho, et al.
(författare)
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Significance of common scatterers in multi-link indoor radio wave propagation
- 2010
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Ingår i: Proceedings of the Fourth European Conference on Antennas and Propagation. - 9781424464319 - 9788476534724
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Konferensbidrag (refereegranskat)abstract
- Correlation between different links is an essential characteristic for many of the forthcoming radio communication systems that utilize the multiple-input-multiple-output (MIMO) technology. This paper investigates the physical phenomena that cause the inter-link correlation by introducing a measure to quantify how large amount of energy propagates via similar propagation mechanisms in different links. The conditions for the so-called significance of common scatterers are derived and two dynamic dual-link indoor MIMO channel measurements are used to provide experimental results. The present work forms the indispensable basis for the channel modeling of multiuser MIMO communications.
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| 23. |
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| 24. |
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