| 1. |
- Guan, Ke, et al.
(författare)
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Towards realistic high-speed train channels at 5G millimeter-wave band - Part I: Paradigm, significance analysis, and scenario reconstruction
- 2018
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Ingår i: IEEE Transactions on Vehicular Technology. - 0018-9545 .- 1939-9359. ; 67:10, s. 9112-9128
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Tidskriftsartikel (refereegranskat)abstract
- The upcoming fifth-generation (5G) mobile communication system is expected to support high mobility up to 500 km/h, which is envisioned in particular for high-speed trains. Millimeter wave (mmWave) spectrum is considered as a key enabler for offering the 'best experience' to highly mobile users. Despite that channel characterization is necessary for the mmWave system design and validation, it is still not feasible to directly do extensive mmWave mobile channel measurements on moving high-speed trains (HST) at a speed up to 500 km/h in the present. Thus, rather than conducting mmWave HST channel sounding directly with high mobility, this study proposes a viable paradigm for realizing the realistic HST channels at the 5G mmWave band. We first propose the whole paradigm. Then, we define the scenario of interest and select the main objects and materials. Afterwards, the electromagnetic and scattering parameters of the materials are measured and estimated between 26.5 GHz and 40 GHz. With this information, the most influential materials are determined through significance analysis. Correspondingly, we reconstruct the three-dimensional mmWave outdoor HST and tunnel scenario models. Through extensive ray-tracing simulations, we determine the main propagation mechanisms in these two scenarios, the channel models based on that are validated by measurements. This verifies the whole paradigm proposed in this paper.
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| 2. |
- Guan, Ke, et al.
(författare)
-
Towards realistic high-speed train channels at 5G millimeter-wave band - Part II: Case study for paradigm implementation
- 2018
-
Ingår i: IEEE Transactions on Vehicular Technology. - 0018-9545 .- 1939-9359. ; 67:10, s. 9129-9144
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Tidskriftsartikel (refereegranskat)abstract
- © 1967-2012 IEEE. In this paper, we present two case studies for generating realistic high-speed train (HST) channels at fifth-generation (5G) millimeter-wave (mmWave) band. The first one is the tunnel environment at relatively low 5G mmWave band, 30 GHz band, whereas the second one is the outdoor HST environment at relatively high 5G mmWave band, 90 GHz band. Both case studies include the following steps: ray-tracing simulations, stochastic channel modeling and realization, verification with ray-tracing simulations, and validation with a reduced set of measurements. A profound and insightful conclusion is reached that by employing the proposed paradigm, realistic channels can be realized for the design and evaluation of 5G mmWave communication systems in high-speed railways, even without the support of sufficient channel sounding data.
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| 3. |
- Peng, Bile, 1985, et al.
(författare)
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Cooperative dynamic angle of arrival estimation considering space-time correlations for terahertz communications
- 2018
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Ingår i: IEEE Transactions on Wireless Communications. - 1558-2248 .- 1536-1276. ; 17:9, s. 6029-6041
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Tidskriftsartikel (refereegranskat)abstract
- © 2002-2012 IEEE. Angle of arrival (AoA) estimation is required by adaptive directive antennas in order to realize a high antenna gain, which is necessary for future indoor terahertz communications due to its extremely high path loss. This paper proposes an AoA estimation algorithm using belief propagation in a dynamic scenario, where the user equipment (UE) is moving during the data transmission, based on the space-time correlations of AoA change. The temporal correlation of AoA change is due to the limited moving speed and statistical movement pattern. Furthermore, if we have distributed antennas or hybrid massive multiple-input-multiple-output (MIMO) array, the AoA changes of different antennas reveal spatial correlation because all the AoA changes are caused by the same spatial displacement of UE. This spatial correlation is utilized in this paper to further improve the estimation accuracy by passing messages between antennas and combining the intrinsic estimate by each antenna and extrinsic information from other antennas. In order to demonstrate the algorithm performance, a distributed antenna system and a hybrid massive MIMO array (an array of multiple directive antenna arrays) are considered as application scenarios. The simulation results show that the cooperative estimation brings significant advantage in both scenarios in respect of mean effective antenna gain and level crossing rate.
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| 4. |
- Peng, Bile, 1985, et al.
(författare)
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Statistical Characteristics Study of Human Blockage Effect in Future Indoor Millimeter and Sub-millimeter Wave Wireless Communications
- 2018
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Ingår i: IEEE Vehicular Technology Conference. - 1550-2252.
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Konferensbidrag (refereegranskat)abstract
- The millimeter and sub-millimeter wave communication is a promising solution to future indoor multi-gigabit wireless communications because of its huge available bandwidth. One of the key difficulties is the human blockage effect since the human body can no longer be considered as being "transparent" as at lower frequencies. In this paper a study of statistical characteristics of this problem is presented. At first, broadband measurements of human blockage are provided. Afterwards, a realis- tic mobility model for indoor movements of humans is adopted and elliptic cylinders are applied to approximate human bodies in ray-launching simulations. Consequently, the distributions of Line-Of-Sight (LOS) path and blockage durations as well as blockage numbers are obtained by simulations. Finally, the system performance in presence of the distributed antennas is evaluated.
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