Search Results for author: Xiang-Gen Xia

Found 20 papers, 3 papers with code

Near Space Communications (NS-COM): A New Regime in Space-Air-Ground Integrated Network (SAGIN)

no code implementations25 Jul 2022 Zhenyu Xiao, Tianqi Mao, Zhu Han, Xiang-Gen Xia

Precipitated by the technological innovations of the near-space platform stations (NSPS), the near space communication (NS-COM) network has emerged as an indispensable part of the next-generation space-air-ground integrated network (SAGIN) that facilitates ubiquitous coverage and broadband data transfer.

LEO Satellite Access Network (LEO-SAN) Towards 6G: Challenges and Approaches

no code implementations25 Jul 2022 Zhenyu Xiao, Junyi Yang, Tianqi Mao, Chong Xu, Rui Zhang, Zhu Han, Xiang-Gen Xia

With the rapid development of satellite communication technologies, the space-based access network has been envisioned as a promising complementary part of the future 6G network.


Terahertz-Band Near-Space Communications: From a Physical-Layer Perspective

no code implementations25 Jul 2022 Tianqi Mao, Leyi Zhang, Zhenyu Xiao, Zhu Han, Xiang-Gen Xia

Facilitated by rapid technological development of the near-space platform stations (NSPS), near-space communication (NS-COM) is envisioned to play a pivotal role in the space-air-ground integrated network for sixth-generation (6G) communications and beyond.

Channel Estimation for LEO Satellite Massive MIMO OFDM Communications

no code implementations25 Jul 2022 Ke-Xin Li, Xiqi Gao, Xiang-Gen Xia

To reduce the computational complexity, we devise a novel two-stage channel estimation (TSCE) approach, in which the received signals at the satellite are manipulated with per-subcarrier space domain processing followed by per-user frequency domain processing.

A three-dimensional dual-domain deep network for high-pitch and sparse helical CT reconstruction

no code implementations7 Jan 2022 Wei Wang, Xiang-Gen Xia, Chuanjiang He, Zemin Ren, Jian Lu

By embedding our implementation into the network, we propose an end-to-end deep network for the high pitch helical CT reconstruction with sparse detectors.

Multi-Layered Recursive Least Squares for Time-Varying System Identification

no code implementations22 Oct 2021 Mohammad Towliat, Zheng Guo, Leonard J. Cimini, Xiang-Gen Xia, Aijun Song

It is shown that the mean square error (MSE) of the m-RLS estimate can be minimized by selecting the optimum number of layers.

Joint 3-D Positioning and Power Allocation for UAV Relay Aided by Geographic Information

no code implementations12 Oct 2021 Pengfei Yi, Liang Zhu, Lipeng Zhu, Zhenyu Xiao, Zhu Han, Xiang-Gen Xia

To improve communication capacity, we first model the blockage effect caused by buildings according to the three-dimensional (3-D) geographic information.

A General Gaussian Heatmap Label Assignment for Arbitrary-Oriented Object Detection

1 code implementation27 Sep 2021 Zhanchao Huang, Wei Li, Xiang-Gen Xia, Ran Tao

Specifically, an anchor-free object-adaptation label assignment (OLA) strategy is presented to define the positive candidates based on two-dimensional (2-D) oriented Gaussian heatmaps, which reflect the shape and direction features of arbitrary-oriented objects.

object-detection Object Detection In Aerial Images

A Survey on Millimeter-Wave Beamforming Enabled UAV Communications and Networking

no code implementations19 Apr 2021 Zhenyu Xiao, Lipeng Zhu, Yanming Liu, Pengfei Yi, Rui Zhang, Xiang-Gen Xia, Robert Schober

The utilization of the millimeter-wave (mmWave) frequency bands is a promising direction for UAV communications, where large antenna arrays can be packed in a small area on the UAV to perform three-dimensional (3D) beamforming.

My Experience in Physical Layer Communications

no code implementations19 Apr 2021 Xiang-Gen Xia

I feel that I have been very lucky since I have experienced the most dynamic 30 years on electronics in the past.

An Adaptive Receiver for Underwater Acoustic Full-Duplex Communication with Joint Tracking of the Remote and Self-Interference Channels

no code implementations11 Mar 2021 Mohammad Towliat, Zheng Guo, Leonard J. Cimini, Xiang-Gen Xia, Aijun Song

Full-duplex (FD) communication is a promising candidate to address the data rate limitations in underwater acoustic (UWA) channels.

$ε$-Arithmetics for Real Vectors and Linear Processing of Real Vector-Valued Signals

no code implementations16 Feb 2021 Xiang-Gen Xia

In this paper, we introduce a new concept, namely $\epsilon$-arithmetics, for real vectors of any fixed dimension.

Information Theory Information Theory

A New Weighting Scheme for Fan-beam and Circle Cone-beam CT Reconstructions

no code implementations6 Jan 2021 Wei Wang, Xiang-Gen Xia, Chuanjiang He, Zemin Ren, Jian Lu, Tianfu Wang, Baiying Lei

In this paper, we first present an arc based algorithm for fan-beam computed tomography (CT) reconstruction via applying Katsevich's helical CT formula to 2D fan-beam CT reconstruction.

Computed Tomography (CT) SSIM

A model-guided deep network for limited-angle computed tomography

1 code implementation10 Aug 2020 Wei Wang, Xiang-Gen Xia, Chuanjiang He, Zemin Ren, Jian Lu, Tianfu Wang, Baiying Lei

In this paper, we first propose a variational model for the limited-angle computed tomography (CT) image reconstruction and then convert the model into an end-to-end deep network. We use the penalty method to solve the model and divide it into three iterative subproblems, where the first subproblem completes the sinograms by utilizing the prior information of sinograms in the frequency domain and the second refines the CT images by using the prior information of CT images in the spatial domain, and the last merges the outputs of the first two subproblems.

Computed Tomography (CT) Image Reconstruction

MMSE Channel Estimation for Two-Port Demodulation Reference Signals in New Radio

no code implementations28 Jul 2020 Dejin Kong, Xiang-Gen Xia, Pei Liu, Qibiao Zhu

In this paper, we firstly propose a minimum mean square error (MMSE) scheme with full priori knowledge (F-MMSE) to achieve the channel estimation of two-port DMRS in NR.

On BT-limited Signals

no code implementations28 May 2020 Xiang-Gen Xia

In this paper, we introduce and characterize a subspace of bandlimited signals.

Self-Interference Channel Characterization in Underwater Acoustic In-Band Full-Duplex Communications Using OFDM

no code implementations21 May 2020 Mohammad Towliat, Zheng Guo, Leonard J. Cimini, Xiang-Gen Xia, Aijun Song

However, in UWA-IBFD, because of reflections from the surface and bottom and the inhomogeneity of the water, a significant part of the transmitted signal returns back to the IBFD receiver.

A deep network for sinogram and CT image reconstruction

1 code implementation20 Jan 2020 Wei Wang, Xiang-Gen Xia, Chuanjiang He, Zemin Ren, Jian Lu, Tianfu Wang, Baiying Lei

A CT image can be well reconstructed when the sampling rate of the sinogram satisfies the Nyquist criteria and the sampled signal is noise-free.

Denoising Image Reconstruction +1

A wavelet frame coefficient total variational model for image restoration

no code implementations25 Aug 2017 Wei Wang, Xiang-Gen Xia, Shengli Zhang, Chuanjiang He

In this paper, we propose a vector total variation (VTV) of feature image model for image restoration.

Image Restoration

Radial Velocity Retrieval for Multichannel SAR Moving Targets with Time-Space Doppler De-ambiguity

no code implementations1 Oct 2016 Jia Xu, Zu-Zhen Huang, Zhi-Rui Wang, Li Xiao, Xiang-Gen Xia, Teng Long

Accordingly, the multichannel SAR systems with different parameters are investigated in three different cases with diverse Doppler ambiguity properties, and a multi-frequency SAR is then proposed to obtain the RV estimation by solving the ambiguity problem based on Chinese remainder theorem (CRT).

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