| 1. |
- Azremi, Abdullah Al-Hadi, et al.
(author)
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Design and Measurement-Based Evaluation of Multi-Antenna Mobile Terminals for LTE 3500 MHz Band
- 2013
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In: Progress in Electromagnetics Research B. - 1937-6472. ; 53:53, s. 241-266
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Journal article (peer-reviewed)abstract
- Design of multi-element antennas for small mobile terminals operating at higher frequencies remains challenging despite smaller antenna dimension and possibility of achieving electrically large separation between them. In this paper, the importance of the type of radiating elements operating at 3400-3600 MHz and their locations on the terminal chassis are highlighted. An isotropic radiation pattern that receives incoming signals from arbitrary directions is obtained by combining the radiation patterns of multiple antennas with localized chassis current distribution. Four multiport antennas configurations with two- and eight-element antennas are designed and evaluated experimentally in indoor propagation environments. Our proposed designs of multi-element antennas provide the highest MIMO channel capacity compared to their counterparts using antennas with less localized chassis current distribution, even in the presence of user's hand.
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| 2. |
- Ghoraishi, Mir, et al.
(author)
-
Towards versatile access networks (Chapter 3)
- 2023
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In: Towards Sustainable and Trustworthy 6G: Challenges, Enablers, and Architectural Design. - 9781638282396 ; , s. 40-120
-
Book chapter (other academic/artistic)abstract
- Compared to its previous generations, the 5th generation (5G) cellular network features an additional type of densification, i.e., a large number of active antennas per access point (AP) can be deployed. This technique is known as massive multipleinput multiple-output (mMIMO) [1]. Meanwhile, multiple-input multiple-output (MIMO) evolution, e.g., in channel state information (CSI) enhancement, and also on the study of a larger number of orthogonal demodulation reference signal (DMRS) ports for MU-MIMO, was one of the Release 18 of 3rd generation partnership project (3GPP Rel-18) work item. This release (3GPP Rel-18) package approval, in the fourth quarter of 2021, marked the start of the 5G Advanced evolution in 3GPP. The other items in 3GPP Rel-18 are to study and add functionality in the areas of network energy savings, coverage, mobility support, multicast broadcast services, and positioning
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| 3. |
- Gustafson, Carl, et al.
(author)
-
Directional analysis of measured 60 GHz indoor radio channels using SAGE
- 2011
-
In: [Host publication title missing]. - 1550-2252. - 9781424483327
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Conference paper (peer-reviewed)abstract
- Abstract in Undetermined Directional properties of the radio channel are of high importance for the development of reliable wireless systems operating in the 60 GHz frequency band. Using transfer functions measured from 61 to 65 GHz in a conference room we have extracted estimates of the multi-path component parameters using the SAGE algorithm. In the paper we compare results for line-of-sight (LOS) scenarios and the corresponding non-line-of-sight (NLOS) scenarios and present values of the direction spread at the Tx and the Rx.
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| 4. |
- Gustafson, Carl, et al.
(author)
-
On mm-Wave Multi-path Clustering and Channel Modeling
- 2014
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In: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 62:3, s. 1445-1455
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Journal article (peer-reviewed)abstract
- Efficient and realistic mm-wave channel models are of vital importance for the development of novel mm-wave wireless technologies. Though many of the current 60 GHz channel models are based on the useful concept of multi-path clusters, only a limited number of 60 GHz channel measurements have been reported in the literature for this purpose. Therefore, there is still a need for further measurement based analyses of multi-path clustering in the 60 GHz band. This paper presents clustering results for a double-directional 60 GHz MIMO channel model. Based on these results, we derive a model which is validated with measured data. Statistical cluster parameters are evaluated and compared with existing channel models. It is shown that the cluster angular characteristics are closely related to the room geometry and environment, making it infeasible to model the delay and angular domains independently. We also show that when using ray tracing to model the channel, it is insufficient to only consider walls, ceiling, floor and tables; finer structures such as ceiling lamps, chairs and bookshelves need to be taken into account as well.
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| 5. |
- Haneda, Katsuyuki, et al.
(author)
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60 GHz Spatial Radio Transmission: Multiplexing or Beamforming?
- 2013
-
In: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 61:11, s. 5735-5743
-
Journal article (peer-reviewed)abstract
- This paper compares the capacity improvement capability of spatial multiplexing and beamforming techniques for 60 GHz spatial transmissions in a multi-carrier radio system such as orthogonal frequency division multiplexing. The term beamforming in this paper refers to the conventional gain focusing, for the strongest propagation path, by narrow antenna beams. Our channel capacity metric depends only on the multipath richness of the propagation channel and the antenna aperture size, but is otherwise independent of the realization of antenna elements on the aperture. Our analysis also reveals the spatial degrees-of-freedom (SDoF) of the radio channel, which is the maximum number of antenna elements on the aperture for efficient spatial multiplexing. We evaluate the capacity and SDoF of single-polarized 60 GHz radio channels measured in a conference room environment. Our results show that the radio channel offers multiple SDoFs both in line-of-sight (LOS) and non-LOS (NLOS) scenarios such that spatial multiplexing can improve the channel capacity, provided that the receive signal-to-noise ratio (SNR) is sufficiently high to utilize them. Under 10 dBm of the transmit power, the high receive SNR is guaranteed when the antenna aperture size is larger than 12 in LOS and 92 in NLOS scenarios, respectively.
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| 6. |
- Haneda, Katsuyuki, et al.
(author)
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Comparison of angular and delay spreads between channel measurements and the COST channel model
- 2010
-
In: ; , s. 477-480
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Conference paper (peer-reviewed)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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| 7. |
- Haneda, Katsuyuki, et al.
(author)
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Comparison of delay and angular spreads between channel measurements and the COST2100 channel model
- 2010
-
In: 2010 Loughborough Antennas and Propagation Conference, LAPC 2010. - 9781424473052 ; , s. 477-480
-
Conference paper (peer-reviewed)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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| 8. |
- Haneda, Katsuyuki, et al.
(author)
-
Feasibility study of a mm-wave impulse radio using measured radio channels
- 2011
-
In: [Host publication title missing]. - 1550-2252. - 9781424483327
-
Conference paper (peer-reviewed)abstract
- Abstract in UndeterminedA millimeter-wave (mm-wave) impulse radio is an attractive alternative to existing high-speed mm- wave radio systems because of the potential for a simpler transceiver architecture. This paper studies the feasibility of a mm-wave impulse radio system for home and office use by considering state-of-the- art transceivers and multiple-input multiple-output measured propagation channels as well as the IEEE 802.15.3c channel model. Our analysis reveals that reliable data transmission is infeasible even in line-of-sight (LOS) scenarios because of a low power level at the Rx if we do not use beamforming. However, introducing 7×7 beamforming at the Tx dramatically improves the coverage beyond 5 m distance in the LOS scenario and up to 5 m in a non- line-of-sight (NLOS) scenario, though the performance varies in the NLOS scenario, depending on the Tx and Rx locations. We propose an adaptive transmit signaling scheme that adjusts the pulse repetition frequency depending on the delay dispersion of the propagation channel in order to avoid intersymbol interference and keep the Rx structure simple. The proposed transmit signaling scheme leads to a pulse transmission rate of 250 Mpulses/s in all measured channels while the rate is lower when the 802.15.3c model is considered because of a more multipath-rich characteristics than our measured channels.
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| 9. |
- Haneda, Katsuyuki, et al.
(author)
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Measurement of loop-back interference channels for outdoor-to-Indoor full-duplex radio relays
- 2010
-
In: Proceedings of the Fourth European Conference on Antennas and Propagation. - 9788476534724 - 9781424464319
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Conference paper (peer-reviewed)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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| 10. |
- Haneda, Katsuyuki, et al.
(author)
-
Radio propagation modeling methods and tools
- 2021
-
In: Inclusive Radio Communications for 5G and Beyond. - 9780128205815 ; , s. 7-48
-
Book chapter (peer-reviewed)abstract
- This chapter provides overview of fundamental definitions, tools and new methods towards improved channel modeling reported in the Co-operation in Science and Technology (COST)-Inclusive Radio Communications (IRACON) Action for future wireless communications and networks. The overview first covers definitions of propagation environments as they determine most relevant propagation mechanisms to consider and model, and furthermore, guide approach to channel modeling methods. This chapter then introduces new insights into popular approaches of channel modeling, i.e., site-specific and geometry-based stochastic channel modeling, where the latter particularly features canonical and standardized channel modeling approaches taken by the 3rd Generation Partnership Project (3GPP), COST, and International Telecommunication Union (ITU) communities. Finally, this chapter shed lights on new modeling approaches to small-scale radio propagation behaviors, covering plane wave propagation paths and distributed diffuse scattering.
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