The application of Non-Orthogonal Multiple Access(NOMA) technology into satelliteaerial-ground integrated networks can meet the requirements of ultra-high rate and massive connectivity for the Sixth-Generation(6G) com...The application of Non-Orthogonal Multiple Access(NOMA) technology into satelliteaerial-ground integrated networks can meet the requirements of ultra-high rate and massive connectivity for the Sixth-Generation(6G) communication systems. We consider an uplink NOMA scenario for such a satellite-aerial-ground integrated network where multiple users communicate with satellite under the help of an Unmanned Aerial Vehicle(UAV) as an aerial relay equipped with a phased array. Supposing that buffer-aided decode-and-forward protocol is adopted at the UAV relay, we first formulate an optimization problem to maximize Ergodic Sum Rate(ESR) of the considered system subject to individual power constraint and quality-of-service constraint of each user.Then, with known imperfect channel state information of each user, we propose a joint power allocation and robust Beam Forming(BF) iterative algorithm to maximize ESR for the user-to-UAV link. Besides, to take the advantages of Free-Space Optical(FSO) and millimeter Wave(mmWave)communications, we present a switch-based hybrid FSO/mmWave scheme and a robust BF algorithm for the UAV-to-satellite link to achieve higher rate. Moreover, a closed-form ESR expression is derived. Finally, the effectiveness and correctness of the proposed solutions are verified by numerical simulations, and the performance evaluation results show that the proposed solutions not only achieve performance enhancement and robustness, but also outperform the orthogonal multiple access significantly.展开更多
High-throughput satellites(HTSs) play an important role in future millimeter-wave(mm Wave) aeronautical communication to meet high speed and broad bandwidth requirements. This paper investigates the outage performance...High-throughput satellites(HTSs) play an important role in future millimeter-wave(mm Wave) aeronautical communication to meet high speed and broad bandwidth requirements. This paper investigates the outage performance of an aeronautical broadband satellite communication system’s forward link, where the feeder link from the gateway to the HTS uses free-space optical(FSO) transmission and the user link from the HTS to aircraft operates at the mm Wave band. In the user link, spot beam technology is exploited at the HTS and a massive antenna array is deployed at the aircraft. We first present a location-based beamforming(BF) scheme to maximize the expected output signal-to-noise ratio(SNR) of the forward link with the amplify-and-forward(AF) protocol,which turns out to be a phased array. Then, by supposing that the FSO feeder link follows Gamma-Gamma fading whereas the mm Wave user link experiences shadowed Rician fading, we take the influence of the phase error into account, and derive the closed-form expression of the outage probability(OP) for the considered system. To gain further insight, a simple asymptotic OP expression at a high SNR is provided to show the diversity order and coding gain. Finally, numerical simulations are conducted to confirm the validity of the theoretical analysis and reveal the effects of phase errors on the system outage performance.展开更多
基金co-supported by the Key International Cooperation Research Project,China(No.61720106003)Jiangsu Province Science and Technology Project,China(No.BE2021031)+4 种基金the Shanghai Aerospace Science and Technology Innovation Foundation,China(No.SAST2019-095)NUPTSF(No.NY220111)the Research Project of Science and Technology on Complex Electronic System Simulation Laboratory,China(No.DXZT-JC-ZZ-2019-009)the National Natural Science Foundation of China(No.61801234)the Postgraduate Research and Practice Innovation Program of Jiangsu Province,China(No.KYCX210739)。
文摘The application of Non-Orthogonal Multiple Access(NOMA) technology into satelliteaerial-ground integrated networks can meet the requirements of ultra-high rate and massive connectivity for the Sixth-Generation(6G) communication systems. We consider an uplink NOMA scenario for such a satellite-aerial-ground integrated network where multiple users communicate with satellite under the help of an Unmanned Aerial Vehicle(UAV) as an aerial relay equipped with a phased array. Supposing that buffer-aided decode-and-forward protocol is adopted at the UAV relay, we first formulate an optimization problem to maximize Ergodic Sum Rate(ESR) of the considered system subject to individual power constraint and quality-of-service constraint of each user.Then, with known imperfect channel state information of each user, we propose a joint power allocation and robust Beam Forming(BF) iterative algorithm to maximize ESR for the user-to-UAV link. Besides, to take the advantages of Free-Space Optical(FSO) and millimeter Wave(mmWave)communications, we present a switch-based hybrid FSO/mmWave scheme and a robust BF algorithm for the UAV-to-satellite link to achieve higher rate. Moreover, a closed-form ESR expression is derived. Finally, the effectiveness and correctness of the proposed solutions are verified by numerical simulations, and the performance evaluation results show that the proposed solutions not only achieve performance enhancement and robustness, but also outperform the orthogonal multiple access significantly.
基金Project supported by the Key International Cooperation Research Project (No. 61720106003)the National Natural Science Foundation of China (No. 61801234)+2 种基金the Shanghai Aerospace Science and Technology Innovation Foundation (No. SAST2019-095)the Research Project of Science and Technology on Complex Electronic System Simulation Laboratory (No. DXZT-JCZZ-2019-009),NUPTSF (No. NY220111)the Postgraduate Research and Practice Innovation Program of Jiangsu Province,China (Nos. KYCX190950 and KYCX200724)。
文摘High-throughput satellites(HTSs) play an important role in future millimeter-wave(mm Wave) aeronautical communication to meet high speed and broad bandwidth requirements. This paper investigates the outage performance of an aeronautical broadband satellite communication system’s forward link, where the feeder link from the gateway to the HTS uses free-space optical(FSO) transmission and the user link from the HTS to aircraft operates at the mm Wave band. In the user link, spot beam technology is exploited at the HTS and a massive antenna array is deployed at the aircraft. We first present a location-based beamforming(BF) scheme to maximize the expected output signal-to-noise ratio(SNR) of the forward link with the amplify-and-forward(AF) protocol,which turns out to be a phased array. Then, by supposing that the FSO feeder link follows Gamma-Gamma fading whereas the mm Wave user link experiences shadowed Rician fading, we take the influence of the phase error into account, and derive the closed-form expression of the outage probability(OP) for the considered system. To gain further insight, a simple asymptotic OP expression at a high SNR is provided to show the diversity order and coding gain. Finally, numerical simulations are conducted to confirm the validity of the theoretical analysis and reveal the effects of phase errors on the system outage performance.
