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.
In recent years, frequency diverse array (FDA) with multiple-input multiple-output (MIMO) technique, which is referred to as FDA-MIMO radar, has attracted extensive attentions due to its outstanding advantages of intr...
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ISBN:
(纸本)9781665435277
In recent years, frequency diverse array (FDA) with multiple-input multiple-output (MIMO) technique, which is referred to as FDA-MIMO radar, has attracted extensive attentions due to its outstanding advantages of introducing additional controllable degrees-of-freedom (DOFs) in range dimension. For FDA-MIMO radar mounted on a moving platform, one big concern is clutter rank. This paper derives the analytical expression of clutter rank in FDA-MIMO radar with range ambiguity. The clutter rank is studied based on subspace transformation and the correlation of vectors in the transformed subspace is explored. Then the maximum resolvable number of range ambiguity can be determined. Simulation results have verified the effectiveness of the proposed method.
Visible light communication (VLC) multiple-input multiple-output (MIMO) technology is a promising technology in 6G. However, the existing capacity formulae for radio frequency (RF) cannot be directly used for VLC due ...
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ISBN:
(纸本)9781728186160
Visible light communication (VLC) multiple-input multiple-output (MIMO) technology is a promising technology in 6G. However, the existing capacity formulae for radio frequency (RF) cannot be directly used for VLC due to the constraints of transmitted signals and unique channel characteristics. In this paper, we make a comparison of different signal distribution. Firstly, we analyze the relationship between transmitted and received signals based on zonotopes model. Then the capacity gap between the truncated Gaussian distribution and uniform distribution is analyzed. Simulations show that the uniform distribution has a better performance than truncated Gaussian, which may promote new signal design for VLC.
Implementing new RF applications has traditionally required significant time and expertise, even for relatively simple algorithms. Software-defined radios (SDRs) have recently enabled rapid implementation and validati...
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ISBN:
(纸本)9781728175867
Implementing new RF applications has traditionally required significant time and expertise, even for relatively simple algorithms. Software-defined radios (SDRs) have recently enabled rapid implementation and validation of RF applications without specialized hardware or advanced programming skills. We further facilitate this rapid application development by constructing WISCANet - a diverse network of commercial SDRs with specialized control software. WISCANet automatically configures these SDRs and controls transmit and receive events with minimal user input. This allows users to rapidly implement over-the-air RF applications by simply defining the baseband processing chain in software. Furthermore, WISCANet emulates real-time operations, which allows users to test real-time applications without the usual complications such as processing speed or hardware limitations. In this paper, we present recent improvements to the WISCA Software-Defined Radio Network (SDR-N). These improvements include configurable and flexible multi-channel phase coherence and support for both MATLAB and Python applications. The open source release of this software may be found on GitHub at: https://***/WISCA
In a reconfigurable intelligent surface (RIS) assisted millimeter Wave (mmWave) communication system, the channel coefficient increases exponentially with the number of RIS elements which results in expensive pilot ov...
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In a reconfigurable intelligent surface (RIS) assisted millimeter Wave (mmWave) communication system, the channel coefficient increases exponentially with the number of RIS elements which results in expensive pilot overhead. Most previous works have proposed some channel estimation algorithms for the estimation accuracy of cascaded channels, which have improved the estimation accuracy, but the pilot overhead is discouraging in the estimation process. To improve the channel estimation accuracy with reduced pilot overhead, we propose a two-stage channel estimation protocol by exploiting semi-passive elements and the coherent time difference of the channel, where the quasi-static channel between the base stations (BS) and RIS is estimated at the RIS, and the user (UE)-RIS time-varying channel is estimated at the BS. In the first stage, we formulate the BS-RIS channel estimation as a mathematical optimization problem by an iterative weighting method and then propose a gradient descent (GD)-based algorithm to solve it. In the second stage, we first transform the received the UE-RIS signal model into an equivalent parallel factor (PARAFAC) tensor model and estimate the UE-RIS channel by the least-squares (LS) algorithm. The simulation results show that the proposed method has better estimation accuracy than the LS, compression sensing (CS) and minimum mean square error (MMSE) methods with less pilot overhead, and the spectral efficiency is improved by at least 10.5% compared to the other three methods.
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