| 1. |
- Wen, Fuxi, 1982, et al.
(författare)
-
A survey on 5G massive MIMO Localization
- 2019
-
Ingår i: Digital Signal Processing: A Review Journal. - : Elsevier BV. - 1051-2004 .- 1095-4333. ; 94:November 2019, s. 21-28
-
Tidskriftsartikel (refereegranskat)abstract
- Massive antenna arrays can be used to meet the requirements of 5G, by exploiting different spatial signatures of users. This same property can also be harnessed to determine the locations of those users. In order to perform massive MIMO localization, refined channel estimation routines and localization methods have been developed. This paper provides a brief overview of this emerging field.
|
|
| 2. |
- Guan, Ke, et al.
(författare)
-
Channel Characterization for Intra-Wagon Communication at 60 and 300 GHz Bands
- 2019
-
Ingår i: IEEE Transactions on Vehicular Technology. - 0018-9545 .- 1939-9359. ; 68:6, s. 5193-5207
-
Tidskriftsartikel (refereegranskat)abstract
- © 1967-2012 IEEE. In this paper, the intra-wagon channels at 60 and 300 GHz bands are characterized through measurement-validated ray-tracing (RT) simulations. To begin with, an in-house-developed three-dimensional RT simulator is calibrated and validated by a series of millimeter-wave and Terahertz channel measurements inside a high-speed train wagon. Then, the validated RT simulator is used to conduct extensive simulations with different transmitter (Tx) and receiver deployments. At low frequencies, the channel is strongly influenced by the line of sight (LOS), and therefore, is usually classified into LOS and non-LOS (NLOS) regions. However, the simulation results at 60 and 300 GHz bands show that the first-order reflection also imposes a significant impact on the channel characteristics. This motivates us to further classify the NLOS region into light-NLOS (L-NLOS) and deep-NLOS (D-NLOS) according to the existence of the first-order reflection. Through analyzing the area ratios of LOS, L-NLOS, and D-NLOS regions, we evaluate the Tx deployment strategies and suggest the optimum one. Based on RT simulation results, totally 12 cases (three propagation regions with two Tx deployments at two frequencies) are characterized in terms of path loss, shadow fading, root-mean-square delay spread, Rician K-factor, azimuth/elevation angular spread of arrival/departure, cross-polarization ratio, and their cross correlations. All these parameters are fed into the 3GPP-like quasi-deterministic radio channel generator (QuaDRiGa). The good agreement between QuaDRiGa and RT proves that the 13 tables provided in this paper effectively parameterize the intra-wagon scenario for the standard channel model family. These results provide valuable insights into the system design and evaluation for intra-wagon communications.
|
|
| 3. |
- Guan, Ke, et al.
(författare)
-
Channel Sounding and Ray Tracing for Train-to-Train Communications at the THz Band
- 2019
-
Ingår i: 13th European Conference on Antennas and Propagation, EuCAP 2019. ; March 2019
-
Konferensbidrag (refereegranskat)abstract
- In order to increase railway capacity for passengers and freight, it is necessary to realize virtual coupling technology through train-to-train (T2T) communications. This T2T link requires large bandwidth for high-data rate and low latency, forming a strong motivation to explore terahertz (THz) band. In this paper, the T2T channel is characterized through ultrawideband (UWB) channel sounding and ray tracing at THz band for the first time. To begin with, a series of T2T channel sounding measurements are performed in a train test center at 300 GHz with 8 GHz bandwidth. Correspondingly, Rician K-factor and root-mean-square (RMS) delay spread are extracted from the measured power-delay profile (PDP). After validated by the measurements, a self-developed ray-tracing (RT) simulator is used to physically interpret the propagation mechanism constitution and significant objects in the target scenario. This provides the first hand information of how the communicating trains themselves influence the T2T channel, and therefore, lays the foundation for channel modeling through extended RT simulations in the future.
|
|
| 4. |
- Guan, Ke, et al.
(författare)
-
Measurement, simulation, and characterization of train-To-infrastructure inside-station channel at the terahertz band
- 2019
-
Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 9:3, s. 291-306
-
Tidskriftsartikel (refereegranskat)abstract
- © 2011-2012 IEEE. In this paper, we measure, simulate, and characterize the train-To-infrastructure (T2I) inside-station channel at the terahertz (THz) band for the first time. To begin with, a series of channel measurements is performed in a train test center at 304.2 GHz with 8 GHz bandwidth. Rician K-factor and root-mean-square (RMS) delay spread are extracted from the measured power-delay profile. With the aid of an in-house-developed ray-Tracing (RT) simulator, the multipath constitution is physically interpreted. This provides the first hand information of how the communicating train itself and the other train on site influence the channel. Using this measurement-validated RT simulator, we extend the measurement campaign to more realistic T2I inside-station channel through extensive simulations with various combinations of transmitter deployments and train conditions. Based on RT results, all cases of the target channel are characterized in terms of path loss, shadow fading, RMS delay spread, Rician K-factor, azimuth/elevation angular spread of arrival/departure, cross-polarization ratio, and their cross correlations. All parameters are fed into and verified by the 3GPP-like quasi-deterministic radio channel generator. This can provide the foundation for future work that aims to add the T2I inside-station scenario into the standard channel model families, and furthermore, provides a baseline for system design and evaluation of THz communications.
|
|
| 5. |
- Guan, Ke, et al.
(författare)
-
Millimeter-wave communications for smart rail mobility: From channel modeling to prototyping
- 2019
-
Ingår i: 2019 IEEE International Conference on Communications Workshops, ICC Workshops 2019 - Proceedings.
-
Konferensbidrag (refereegranskat)abstract
- In this paper, we present an integration solution from channel modeling to prototyping, to realize millimeter-wave (mmWave) communications for smart rail mobility. In order to involve the railway features in the channel models, two mmWave channel models are established based on ray-tracing simulations in realistic railway scenarios. Moreover, the challenges raised by mmWave directional network under high mobility is overcome by our solutions concerning handover scheme, random access procedure, and beamforming strategies. By integrating these key enabling technologies, we prototype the mobile hotspot network (MHN) system which realizes 1.25 Gbps downlink data throughput in a subway line with the train speed of 80 km/h.
|
|
| 6. |
- Keskin, Furkan, 1988, et al.
(författare)
-
Freeway Traffic Jam Mitigation via Connected Automated Vehicles
- 2019
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We consider the problem of altruistic control of connected automated vehicles (CAVs) on multi-lane highways to mitigate phantom traffic jams resulting from car-following dynamics of human-driven vehicles (HDVs). In most of the existing studies on CAVs in multi-lane settings, vehicle controller design philosophy is based on a selfish driving strategy that exclusively addresses the ego vehicle objectives. To improve overall traffic smoothness, we propose an altruistic control strategy for CAVs that aims to maximize the driving comfort and traffic efficiency of both the ego vehicle and surrounding HDVs. We formulate the problem of altruistic control under a model predictive control (MPC) framework to optimize acceleration and lane change sequences of CAVs. Simulation results demonstrate significant improvements in traffic flow via altruistic CAV actions over selfish strategies.
|
|
| 7. |
- Peng, Bile, 1985, et al.
(författare)
-
Decentralized Scheduling for Cooperative Localization With Deep Reinforcement Learning
- 2019
-
Ingår i: IEEE Transactions on Vehicular Technology. - : Institute of Electrical and Electronics Engineers Inc.. - 0018-9545 .- 1939-9359. ; 68:5, s. 4295-4305
-
Tidskriftsartikel (refereegranskat)abstract
- Cooperative localization is a promising solution to the vehicular high-accuracy localization problem. Despite its high potential, exhaustive measurement and information exchange between all adjacent vehicles are expensive and impractical for applications with limited resources. Greedy policies or hand-engineering heuristics may not be able to meet the requirement of complicated use cases. In this paper, we formulate a scheduling problem to improve the localization accuracy (measured through the Cramér-Rao lower bound) of every vehicle up to a given threshold using the minimum number of measurements. The problem is cast as a partially observable Markov decision process and solved using decentralized scheduling algorithms with deep reinforcement learning, which allow vehicles to optimize the scheduling (i.e., the instants to execute measurement and information exchange with each adjacent vehicle) in a distributed manner without a central controlling unit. Simulation results show that the proposed algorithms have a significant advantage over random and greedy policies in terms of both required numbers of measurements to localize all nodes and achievable localization precision with limited numbers of measurements.
|
|
| 8. |
- Peng, Bile, 1985, et al.
(författare)
-
Power-Angular Spectra Correlation Based Two Step Angle of Arrival Estimation for Future Indoor Terahertz Communications
- 2019
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 67:11
-
Tidskriftsartikel (refereegranskat)abstract
- The future terahertz (THz) communication is a promising solution to the high-data-rate and short-range communication due to its broad available bandwidth. However, the high propagation path loss and the limited output power of the amplifier require highly directive antennas with high antenna gain in order to realize a reasonable signal-to-noise ratio (SNR). An angle of arrival (AoA) estimation is necessary to adjust the main lobe direction of the antenna. A major challenge of the AoA estimation is the compromise between accuracy and time consumption due to the big number of main lobe directions. This paper proposes a novel efficient AoA algorithm, which utilizes the fact that the power angular spectra (PAS) of different frequencies are highly correlated and the THz communication devices are equipped with radio frequency (RF) frontends of lower frequency. By means of a rough and quick estimation at the lower frequency, the range of the true AoA can be confined significantly and the precise estimation can be carried out efficiently. To begin with, an antenna model with discrete main lobe directions is proposed and the relationship between antenna gain, half power beam width (HPBW) and number of main lobe directions is analyzed. The PAS correlation is then validated with channel sounding measurement. The two-step AoA estimation algorithm is derived, formulated and finally validated with hardware demonstration.
|
|
| 9. |
- Peng, Bile, 1985, et al.
(författare)
-
Precoding and Detection for Broadband Single Carrier Terahertz Massive MIMO Systems Using LSQR Algorithm
- 2019
-
Ingår i: IEEE Transactions on Wireless Communications. - 1558-2248 .- 1536-1276. ; 18:8599164, s. 1026-1040
-
Tidskriftsartikel (refereegranskat)abstract
- The terahertz (THz) communication utilizes the frequency spectrum above 300 GHz and is widely considered as a promising solution to the future high-speed short-range wireless communication beyond millimeter wave (mmWave) communication. While providing tens of gigahertz bandwidth, it is subjected to high propagation path loss, inter-symbol and inter-user interferences. The massive multiple-input- multiple-output (MIMO) can be applied to address these problems by cooperation between many access point (AP) antennas. However, the THz channel characteristics, including high propagation path loss, frequency selectivity and big number of samples per channel impulse response (CIR), require carefully tailored algorithm for massive MIMO signal processing. In this paper, we propose a single carrier minimum mean square error (MMSE) precoding and detection algorithm for frequency selective THz channels. The MIMO signal transmission is described with the block matrices. A gain control heuristic is introduced to reduce the complexity. The sparsity property of the channel is utilized to construct sparse channel matrices and the least square QR (LSQR) algorithm is applied to efficiently solve the problems. Besides the uniform antenna array, the hybrid array consisting of several subarrays is considered as well. Simulation results show that the massive MIMO array can provide a satisfactory performance in terms of bit error rate (BER).
|
|
| 10. |
- Xie, Wenjing, et al.
(författare)
-
An Improved Algorithm Based on Particle Filter for 3D UAV Target Tracking
- 2019
-
Ingår i: IEEE International Conference on Communications. - 1550-3607. ; 2019-May
-
Konferensbidrag (refereegranskat)abstract
- The widespread application of unmanned aerial vehicles (UAVs) urgently requires an effective tracking algorithm as technical support. Particle filter has been widely applied in maneuvering target tracking, however, there has been no suitable solution to the trade-off between weight degeneracy and particle diversity during the process of resampling. In this paper, we propose an improved particle filter algorithm based on systematic resampling with additional random perturbation. This method ensures that particle filter maintains particle diversity and reduces weight degeneracy under environments with different noise types, simultaneously. The simulation results demonstrate that the proposed algorithm generates more accurate filtered trajectory than generic particle filter, especially under the environment with low noise.
|
|
