scholarly journals A Cross-Mode Universal Digital Pre-Distortion Technology for Low-Sidelobe Active Antenna Arrays in 5G and Satellite Communications

Electronics ◽  
2021 ◽  
Vol 10 (16) ◽  
pp. 2031
Author(s):  
Yunfeng Li ◽  
Yonghui Huang ◽  
Martin Hedegaard Nielsen ◽  
Feridoon Jalili ◽  
Wei Wei ◽  
...  
Keyword(s):  
Antenna Arrays ◽  
Orthogonal Frequency Division Multiplexing ◽  
Large Scale ◽  
Satellite Communications ◽  
Input Power ◽  
Active Antenna ◽  
Operating Modes ◽  
Low Sidelobe ◽  
Ofdm Signal ◽  
Fixed Power

A cross-mode universal digital pre-distortion (CMUDPD) technology is proposed here to linearize low-sidelobe active antenna arrays with non-uniform fixed power levels for each branch, which are desired in satellite communications with stringent requirements to minimize interference. In low-sidelobe arrays formed by nonuniform amplitude excitation, conventional digital pre-distortion (DPD) techniques require multiple feedback paths for either one-to-one or average linearization of the PAs, which increases system complexity and is infeasible for large-scale arrays. This is because the power amplifiers (PAs) usually operate in different modes where the supply voltages, bias voltages, and input power levels are different. The proposed CMUDPD method aims at solving this issue by intentionally arranging the PAs to work in different modes but with shared nonlinear characteristics. Based on the nonlinear correlation established among the PAs’ different operating modes, a single feedback path is sufficient to capture the common nonlinearity of all the PAs and determine the parameters of the CMUDPD module. The concept is explained in theory and validated by simulations and experiments using GaN PAs operating with three significantly different output power levels and two orthogonal frequency division multiplexing (OFDM) signal bandwidths.

scholarly journals A Receiver Architecture For Dual-Functional Massive MIMO OFDM RadCom Systems

2020 ◽  
Author(s):  
Murat Temiz ◽  
Emad Alsusa ◽  
Laith Danoon
Keyword(s):  
Antenna Arrays ◽  
Interference Cancellation ◽  
Orthogonal Frequency Division Multiplexing ◽  
Large Scale ◽  
Spatial Diversity ◽  
Base Stations ◽  
Communication Signals ◽  
Dual Functional ◽  
Receiver Architecture ◽  
Radar Signals

This study introduces a receiver architecture for dual-functional communication and radar (RadCom) base-stations (BS), which exploits the spatial diversity between the received radar and communication signals, and performs interference cancellation (IC) to successfully separate these signals. In the RadCom system under consideration, both communication and radar systems employ orthogonal frequency-division multiplexing (OFDM) waveforms with overlapping subcarriers. Employing OFDM waveform allows the BS to simultaneously perform uplink channel estimation on the narrow-band subcarriers to efficiently obtain full channel state information (CSI) between the users (UEs) and the BS antenna elements. The estimated CSI matrix is then utilized to acquire uplink data streams from the UEs by suppressing the inter-user interference and radar signals which arrive at the BS through unknown channels. After acquiring the UEs' data, radar signals are extracted from the received complex baseband signals by performing interference cancellation. The proposed method has been analyzed mathematically and verified by simulations under various conditions including CSI mismatch and high radar interference. The results show that 16QAM modulated uplink is outstandingly robust against radar interference and that having a large number of antennas significantly improves the performance of both communication and radar subsystems, cooperatively. This study shows that it is possible to distinguish radar and communication signals by employing large-scale antenna arrays to successfully realize a RadCom receiver for future communication networks

scholarly journals A Receiver Architecture For Dual-Functional Massive MIMO OFDM RadCom Systems

2020 ◽  
Author(s):  
Murat Temiz ◽  
Emad Alsusa ◽  
Laith Danoon
Keyword(s):  
Antenna Arrays ◽  
Interference Cancellation ◽  
Orthogonal Frequency Division Multiplexing ◽  
Large Scale ◽  
Spatial Diversity ◽  
Base Stations ◽  
Communication Signals ◽  
Dual Functional ◽  
Receiver Architecture ◽  
Radar Signals

This study introduces a receiver architecture for dual-functional communication and radar (RadCom) base-stations (BS), which exploits the spatial diversity between the received radar and communication signals, and performs interference cancellation (IC) to successfully separate these signals. In the RadCom system under consideration, both communication and radar systems employ orthogonal frequency-division multiplexing (OFDM) waveforms with overlapping subcarriers. Employing OFDM waveform allows the BS to simultaneously perform uplink channel estimation on the narrow-band subcarriers to efficiently obtain full channel state information (CSI) between the users (UEs) and the BS antenna elements. The estimated CSI matrix is then utilized to acquire uplink data streams from the UEs by suppressing the inter-user interference and radar signals which arrive at the BS through unknown channels. After acquiring the UEs' data, radar signals are extracted from the received complex baseband signals by performing interference cancellation. The proposed method has been analyzed mathematically and verified by simulations under various conditions including CSI mismatch and high radar interference. The results show that 16QAM modulated uplink is outstandingly robust against radar interference and that having a large number of antennas significantly improves the performance of both communication and radar subsystems, cooperatively. This study shows that it is possible to distinguish radar and communication signals by employing large-scale antenna arrays to successfully realize a RadCom receiver for future communication networks

A 2 × 20 Gbps hybrid MDM-OFDM–based high-altitude platform-to-satellite FSO transmission system

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Vel Murugan Gomathy ◽  
T. V. Paramasivam Sundararajan ◽  
C. Sengodan Boopathi ◽  
Pandiyan Venkatesh Kumar ◽  
Krishnamoorthy Vinoth Kumar ◽  
...  
Keyword(s):  
High Altitude ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Satellite Communication ◽  
Input Power ◽  
Transmission System ◽  
Communication Link ◽  
Space Optics ◽  
High Altitude Platform ◽  
Mode Division Multiplexing

AbstractIn the present study, the application of free space optics (FSO) transmission system to realize a long-reach high-altitude platform (HAP)-to-satellite communication link has been exploited. High-speed information transmission without interference is accomplished using orthogonal frequency division multiplexing (OFDM). Further, the information capacity of the proposed system is increased by employing mode division multiplexing (MDM). We have investigated the proposed MDM-OFDM-HAP-to-satellite FSO transmission system performance over varying FSO range, diameter of the receiver, pointing errors, and input power. Also, an improved transmission performance of the proposed system using a square root module is reported.

Over-the-Air Calibration of Active Antenna Arrays Using Multisine

2021 ◽  
Vol 69 (1) ◽  
pp. 431-442
Author(s):  
Marina Jordao ◽  
Daniel Belo ◽  
Rafael F. S. Caldeirinha ◽  
Arnaldo S. R. Oliveira ◽  
Nuno Borges de Carvalho
Keyword(s):  
Antenna Arrays ◽  
Active Antenna

Experimental Study on Wear Monitoring of Marine Diesel Engine’s Piston Ring by Magnetoresistive Sensor

2012 ◽  
Vol 424-425 ◽  
pp. 132-136
Author(s):  
Guo Jin Chen ◽  
Zhang Ming Peng ◽  
Jian Guo Yang ◽  
Qiao Ying Huang
Keyword(s):  
Diesel Engine ◽  
Large Scale ◽  
Piston Ring ◽  
Test Bed ◽  
Operating Modes ◽  
Magnetoresistive Sensor ◽  
Marine Diesel ◽  
Wear Monitoring ◽  
Oil Tanker ◽  
Test Result

On the diesel engine’s test bed, this paper has studied the parameters regarding the diesel engine’s rotational speed, the piston ring’s width and wearing capacity and so on, and their relation with the output signal of the magnetoresistive sensor under the reverse drawing of the diesel engine. The research discovered that the piston ring’s wear and the magnetoresistive sensor’s output have the corresponding relationship. And on the oil tanker with the 6RTA52U diesel engine, the influence of the diesel engine’s operating parameters and the load situations to the magnetoresistive sensor’s output is surveyed under four kinds of different operating modes. The test result and the research conclusion provide the technical foundation for the online Wear monitoring of the large-scale marine diesel engine’s piston ring.

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