Distributed beamforming; imperfect delay and doppler compensation; multiple LEO satellites; Average rate; Delay compensation; Doppler compensations; Downlink transmissions; Imperfect delay and dopple compensation; Low earth orbit satellites; Multiple low earth orbit satellite; Transmission performance; User terminals; Automotive Engineering; Aerospace Engineering; Computer Networks and Communications; Electrical and Electronic Engineering; Satellites; Array signal processing; Delays; Doppler effect; Symbols; OFDM; Antenna arrays; Vectors; Interference
Abstract :
[en] To improve the transmission performance of low Earth orbit (LEO) satellites limited by practical constraints of transmit power, antenna array size, and antenna gain in single satellites, multiple LEO satellites can be leveraged to cooperatively serve terrestrial user terminals (UTs). This paper investigates cooperative downlink (DL) transmission from multiple LEO satellites by using distributed beamforming, considering the inevitable delay and Doppler compensation errors that impact coherent processing. Firstly, we establish the DL transmission signal model for multiple LEO satellites with delay and Doppler compensation errors. On this basis, we design the transmitters and receivers to maximize the average signal-to-leakage-plus-noise ratio. Then, we analyze the DL transmission performance via deriving lower bounds and closed-form expressions for both the user rate and the average rate gain of cooperative transmission compared to single LEO satellite transmission. We prove that as the number of receiving antennas at the UT increases, the impact of imperfect compensation on the user rate decreases, and the average rate gain improves. In addition, we prove that the UT can achieve the optimal average rate gain when its array response vectors corresponding to different LEO satellites are orthogonal. Simulations are performed and compared to the theoretical analysis, demonstrating the performance gains brought by distributed beamforming and validating our analysis.
Disciplines :
Electrical & electronics engineering
Author, co-author :
Wu, Shiyu; National Mobile Communications Research Laboratory, Nanjing, China ; Purple Mountain Laboratories, Nanjing, China
Wang, Yafei ; National Mobile Communications Research Laboratory, Nanjing, China ; Purple Mountain Laboratories, Nanjing, China
Sun, Gangle ; National Mobile Communications Research Laboratory, Nanjing, China ; Purple Mountain Laboratories, Nanjing, China
Wang, Wenjin ; National Mobile Communications Research Laboratory, Nanjing, China ; Purple Mountain Laboratories, Nanjing, China
Wang, Jiaheng ; National Mobile Communications Research Laboratory, Nanjing, China ; Purple Mountain Laboratories, Nanjing, China
OTTERSTEN, Björn ; University of Luxembourg > Interdisciplinary Centre for Security, Reliability and Trust (SNT) > PI Ottersten
External co-authors :
yes
Language :
English
Title :
Distributed Beamforming for Multiple LEO Satellites With Imperfect Delay and Doppler Compensations: Modeling and Rate Analysis
Publication date :
2025
Journal title :
IEEE Transactions on Vehicular Technology
ISSN :
0018-9545
Publisher :
Institute of Electrical and Electronics Engineers Inc.
National Key R&D Program of China National Natural Science Foundation of China Jiangsu Province Basic Research Project Satellite Internet Key Laboratory in 2024 Luxembourg National Research Fund
Funding text :
Received 31 May 2024; revised 20 December 2024 and 10 March 2025; accepted 15 April 2025. Date of publication 9 May 2025; date of current version 19 September 2025. This work was supported in part by the National Key R&D Program of China under Grant 2023YFB2904703, in part by the National Natural Science Foundation of China under Grant 62371122, in part by Jiangsu Province Basic Research Project under Grant BK20192002, and in part by the open project of Satellite Internet Key Laboratory in 2024 (Project 6: Research and Experimental Verification of Multi-Satellite Collaborative Direct to Cell Transmission Methods). The work of Bj\u00F6rn Ottersten was supported by Luxembourg National Research Fund (FNR) under Grant INTER/MOBILITY/2023/IS/18014377/MCR. The review of this article was coordinated by Dr. Chau Yuen. (Shiyu Wu and Yafei Wang contributed equally to this work.) (Corresponding author: Wenjin Wang.) Shiyu Wu, Yafei Wang, Gangle Sun, Wenjin Wang, and Jiaheng Wang are with National Mobile Communications Research Laboratory, Nanjing 210096, China, and also with Purple Mountain Laboratories, Nanjing 211100, China (e-mail: wushiyu@seu.edu.cn; wangyf@seu.edu.cn; sungangle@seu.edu.cn; wangwj@seu.edu.cn; jhwang@seu.edu.cn).
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