LiFi has been considered as a promising candidate for future wireless indoor networks. The IEEE P802.15.13 and P802.11bb standardization groups agreed upon channel models generated using the non-sequential ray tracing...
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LiFi has been considered as a promising candidate for future wireless indoor networks. The IEEE P802.15.13 and P802.11bb standardization groups agreed upon channel models generated using the non-sequential ray tracing approach of OpticStudio. In this paper, in order to validate the channel modelling approach, at first 2x2 multiple-input multiple-output (MIMO) channel measurements are carried out over 200 MHz bandwidth using a channel sounder. The experimental scenario is also modeled in 3D by applying ray tracing. The obtained results indicate good agreement between simulations and measured channel impulse responses, from which parameters such as path loss and delay spread are derived. After validating the channel modeling approach, we investigate the singular values and the effect of user mobility onto the performance in a 4x4 distributed multi-user MIMO scenario.
Reconfigurable intelligent surface (RIS) has recently drawn significant attention in wireless communication technologies. However, identifying, modeling, and estimating the RIS channel in multiple-inputmultiple-outpu...
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ISBN:
(纸本)9781728175867
Reconfigurable intelligent surface (RIS) has recently drawn significant attention in wireless communication technologies. However, identifying, modeling, and estimating the RIS channel in multiple-input multiple-output (MIMO) systems are considered challenging in recent studies. In this paper, a disassembled channel estimation framework for the RIS-MIMO system is proposed based on the eigenvalue decomposition (EVD) concept to separate the cascaded channel links and estimate each link separately. This estimation is based on modeling the RIS-MIMO channel as a keyhole MIMO system model. Numerical results show that the proposed estimation method has a low estimation time overhead while providing less estimation error.
Estimation of communication parameters, a major task of intelligent receivers, has important applications in adaptive wireless systems. multiple antennas make the identification problem more challenging. In this paper...
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ISBN:
(纸本)9781728186160
Estimation of communication parameters, a major task of intelligent receivers, has important applications in adaptive wireless systems. multiple antennas make the identification problem more challenging. In this paper, we focus on the problem of estimating the number of transmit antennas in multiple-input-multiple-output (MIMO) communication systems. A novel estimation algorithm is proposed to determine the number of transmit antennas for MIMO with alpha-stable noise. We first introduce the correlation matrix based on the fractional lower order statistics (FLOS) and provide a particular structure of FLOS-based correlation matrix. Then, the eigenvalues of the FLOS-based correlation matrix are employed to construct a test statistic and the central limit theorem is exploited to obtain the decision threshold. Finally, the transmit-antenna number is estimated using a serial binary hypothesis test. Simulation results are demonstrated to evaluate the effectiveness of the proposed transmit-antenna number estimation algorithm for MIMO with alpha-stable noise.
Aiming at the current ultra-wideband multiple-input multiple-output (UWB-MIMO) antenna, which had a large size, low isolation, and other deficiencies, a miniaturized, high-isolation UWB-MIMO antenna was designed. The ...
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ISBN:
(纸本)9798400709265
Aiming at the current ultra-wideband multiple-input multiple-output (UWB-MIMO) antenna, which had a large size, low isolation, and other deficiencies, a miniaturized, high-isolation UWB-MIMO antenna was designed. The antenna's backside was a rectangular ground plate with cutting corners, while the front side was made up of a "vase"-style radiation patch and a stepped microstrip feeder. The antenna was broad-banded by symmetrically cutting the corners of the rectangular radiating patch and etching the rectangular slot on the ground plate. The antenna achieved high isolation by loading a "fishbone" and symmetrical "Y" decoupling stubs on the front and back of the dielectric substrate. The antenna was simulated and measured with a size of only 22 mm × 29 mm × 0.8 mm, having an operating bandwidth of 1.5∼18 GHz (the relative bandwidth reaches 169%), isolation more significant than 17 dB in the bandwidth range, and an envelope correlation coefficient (ECC) of less than 0.02. The antenna can be utilized in UWB-MIMO wireless communication systems since it has good radiation performance and a small structure.
In an inductive power transfer (IPT) consisting of one transmitter and one receiver, series resonant capacitors are inserted on both sides to achieve high power transfer efficiency and load-independent output current....
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ISBN:
(纸本)9784885523267
In an inductive power transfer (IPT) consisting of one transmitter and one receiver, series resonant capacitors are inserted on both sides to achieve high power transfer efficiency and load-independent output current. However, when IPT is carried from multiple transmitters to multiple receivers, the load currents vary with the load resistances due to impact of cross talk among the coils. As an initial attempt to address this problem, we proposed 2 x 2 series resonant scheme to mitigate cross talk and achieve constant load currents for IPT system with two transmitters and two receivers. Effectiveness of our proposal is confirmed by experiments.
Deep learning has demonstrated the important roles in improving the system performance and reducing computational complexity for 5G-and-heyond networks. In this paper, we propose a new channel estimation method with t...
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ISBN:
(纸本)9781665423182
Deep learning has demonstrated the important roles in improving the system performance and reducing computational complexity for 5G-and-heyond networks. In this paper, we propose a new channel estimation method with the assistance of deep learning in order to support the least squares estimation, which is a low-cost method but having relatively high channel estimation errors. This goal is achieved by utilizing a MIMO (multiple-input multiple-output) system with a multi-path channel profile used for simulations in the 5G networks under the severity of Doppler effects. Numerical results demonstrate the superiority of the proposed deep learning-assisted channel estimation method over the other channel estimation methods in previous works in terms of mean square errors.
In visible light communication systems, the ability to suppress interference caused by other light sources is a major benefit towards performance improvements. Especially for large transmitter arrays or even multi-cel...
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In visible light communication systems, the ability to suppress interference caused by other light sources is a major benefit towards performance improvements. Especially for large transmitter arrays or even multi-cell arrangements, the interference problem needs to be handled. In previous work, we have presented a liquid crystal display (LCD) used as an adaptive interference-suppression filter mounted in front of each photodetector. The display elements are switched on and off in such a way that light emitted by unwanted light sources ideally is blocked, but light emitted by desired light sources reaches the detector. The pattern generated by the LC display has strong impact on the system performance. In this paper, we propose combined precoding in conjunction with LCD-based interference suppression in order to increase the signal-to-interference-plus-noise ratio and to ensure user fairness in massive MIMO scenarios. The suggested precoding strategy uses a new heuristic optimization approach based on the Santa Claus problem on unrelated machines known from computer sciences, and employs only binary entries in the weighting matrix. Corresponding results are compared with a genetic evolutionary optimization strategy and with conventional zero-forcing precoding. Regarding performance evaluation, we perform numerical ray-tracing simulations and present a room-scale VLC testbed for experimental verification.
During the evolution from LTE to NR, multiantenna technology is a key technology to improve the overall system throughput. The multi-antenna technology is an effective means to increase system capacity compared with n...
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ISBN:
(纸本)9781665416580
During the evolution from LTE to NR, multiantenna technology is a key technology to improve the overall system throughput. The multi-antenna technology is an effective means to increase system capacity compared with networks extension. The more the antenna arrays are, the narrower the beams become to achieve better isolation and interference control. Based on narrow beams formed by beamforming, the same spectrum resources are reused in the same geographic area to obtain resource multiplexing gains. Negatively, as the multi-antenna solution, coverage overlapping increases and inter-cell load imbalance occurs accordingly, which is a key problem to be addressed in the network optimization practice.
Fixed-Complexity Sphere Decoder (FSD) is an quasi-optimal detector for multiple-input multiple-output (MIMO) system which is a hardware-friendly parallel tree-search customised to the modulation and antenna scheme emp...
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ISBN:
(纸本)9781665401449
Fixed-Complexity Sphere Decoder (FSD) is an quasi-optimal detector for multiple-input multiple-output (MIMO) system which is a hardware-friendly parallel tree-search customised to the modulation and antenna scheme employed. However, it is not able to adapt its behaviour for various modulation and antenna schemes, as demanded by modern wireless standard. This restricts its usage in modern adaptive MIMO systems. This paper proposes a solution to this problem. A configurable FSD structure in proposed where normalized higher order modulation schemes can accommodate lower ones. By exploiting clock-gating, FSD of all modulation schemes is equally trimmed to allow power savings of over 30% when implementing on Field Programmable Gate Array (FPGA). This architecture enables the facility to balance the power consumptions with compatible information rate in dynamic, adaptive MIMO communications environments.
In this paper, we propose a novel detection algorithm of the number of transmit antennas in multiple-input multiple-output (MIMO) systems, assuming that signals corrupted by non-Gaussian interference and Gaussian nois...
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ISBN:
(纸本)9781665413688
In this paper, we propose a novel detection algorithm of the number of transmit antennas in multiple-input multiple-output (MIMO) systems, assuming that signals corrupted by non-Gaussian interference and Gaussian noise. We first introduce generalized correlation matrix. Then, the discriminating feature vector is constructed by exploiting the higher-order moment of the eigenvalues. Finally, an advanced clustering algorithm is employed for decision the number of transmit antennas, which is determined by the dimension of the cluster where the minimum eigenvalue is located. The proposed algorithm does not require a priori information about the transmitted signals, such as coding scheme, modulation type, and pilot patterns. Simulation results are demonstrated to evaluate the effectiveness of the proposed transmit-antenna number detection algorithm in MIMO systems with Gaussian Noise and non-Gaussian interference.
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