Optimizing the power resources allocation method of low earth orbit(LEO)satellites to medium earth orbit(MEO)satellite'links is a significant way to construct efficient satellite constellations for satellite commu...Optimizing the power resources allocation method of low earth orbit(LEO)satellites to medium earth orbit(MEO)satellite'links is a significant way to construct efficient satellite constellations for satellite communication.A game theory power allocation method based on remaining visible time(RVT)of LEO-MEO satellites is proposed.Firstly,one LEO-MEO satellite network is classified as a cluster in which the RVT of LEO satellites is modeled.Secondly,the cost function of RVT concerning the character of orbit and throughput in each LEO satellite is mainly designed,which gives greater punishment of utility value to LEO satellites with less RVT and is an essential part of the reasonable utility function applied in diverse motion scenes.Meanwhile,the existence of Nash equilibrium for the proposed utility function in game theory area is proved.Thirdly,an off-cluster scheme for LEO satellites through the proposed threshold is raised to ensure the overall utility value of the whole LEO satellites in cluster.Finally,the performance improvement of the proposed algorithm to the baseline algorithm is verified through simulations in different scenarios.展开更多
The low earth orbit(LEO) satellite system provides a promising solution for the global coverage of Internet of Things(IoT) services.Confronted with the sporadic uplink transmission from massive IoT terminals, this wor...The low earth orbit(LEO) satellite system provides a promising solution for the global coverage of Internet of Things(IoT) services.Confronted with the sporadic uplink transmission from massive IoT terminals, this work investigates the grant-free access scheme and resource allocation algorithm for the beam-hopping(BH) based LEO satellite systems.To improve the packet success rate, the time slots are pre-allocated to each cell according to the number of terrestrial terminals and the probability of packet arrival.When the packets arrive, the terrestrial terminals perform contention-free or contention-based grant-free access with packet repetition in the time slots allocated to their cells.The analytical expression of the packet collision probability for the grant-free access scheme is derived to provide reference for the resource allocation.To reduce the computational complexity, a heuristic resource allocation algorithm is proposed to minimize the maximum cell packet collision probability in the system.Simulation results show that the proposed resource allocation scheme achieves lower packet collision probability and higher resource utilization ratio when compared with the uniform resource allocation scheme.展开更多
We propose a novel vertical Bell Laboratories layered space-time (V-BLAST) based two-way relayingprotocol that comprises two user terminals and one multi-antenna demodulate-and-forward (DMF) relaystation. We consider ...We propose a novel vertical Bell Laboratories layered space-time (V-BLAST) based two-way relayingprotocol that comprises two user terminals and one multi-antenna demodulate-and-forward (DMF) relaystation. We consider the situation when these two user terminals employ different modulation types andinvestigate its detection techniques. The key feature of the detection techniques is that we quantify decisionreliability at the relay station by introducing a so-called normalized correlation coefficient (CORR),rather than having full confidence in demodulation at the relay station. With the assistance of the normalizedconelation coefficient, we develop detection methods at both the relay station and user terminals. Inparticular, we propose a CORR-based ordering algorithm at the relay station which can be applied to detectionfor general V-BLAST architectures. Simulation results demonstrate the superiority of the CORR-basedordering algorithm over the conventional signal-to-noise based ordering algorithm. Finally, wedemonstrate overall error-performance of the V-BLAST-based DMF two-way relaying protocol via simulations.展开更多
基金Supported by the National Key Research and Development Program of China(No.2019YFB1803101)the Natural Science Foundation of Shanghai(No.19ZR1467200).
文摘Optimizing the power resources allocation method of low earth orbit(LEO)satellites to medium earth orbit(MEO)satellite'links is a significant way to construct efficient satellite constellations for satellite communication.A game theory power allocation method based on remaining visible time(RVT)of LEO-MEO satellites is proposed.Firstly,one LEO-MEO satellite network is classified as a cluster in which the RVT of LEO satellites is modeled.Secondly,the cost function of RVT concerning the character of orbit and throughput in each LEO satellite is mainly designed,which gives greater punishment of utility value to LEO satellites with less RVT and is an essential part of the reasonable utility function applied in diverse motion scenes.Meanwhile,the existence of Nash equilibrium for the proposed utility function in game theory area is proved.Thirdly,an off-cluster scheme for LEO satellites through the proposed threshold is raised to ensure the overall utility value of the whole LEO satellites in cluster.Finally,the performance improvement of the proposed algorithm to the baseline algorithm is verified through simulations in different scenarios.
基金Supported by the Science and Technology Innovation Action Plan of Shanghai (No. 21DZ2200200)the Science and Technology Cooperation Funding of Chengdu and CASthe National Key Research and Development Program of China (No. 2019YFB1803101)。
文摘The low earth orbit(LEO) satellite system provides a promising solution for the global coverage of Internet of Things(IoT) services.Confronted with the sporadic uplink transmission from massive IoT terminals, this work investigates the grant-free access scheme and resource allocation algorithm for the beam-hopping(BH) based LEO satellite systems.To improve the packet success rate, the time slots are pre-allocated to each cell according to the number of terrestrial terminals and the probability of packet arrival.When the packets arrive, the terrestrial terminals perform contention-free or contention-based grant-free access with packet repetition in the time slots allocated to their cells.The analytical expression of the packet collision probability for the grant-free access scheme is derived to provide reference for the resource allocation.To reduce the computational complexity, a heuristic resource allocation algorithm is proposed to minimize the maximum cell packet collision probability in the system.Simulation results show that the proposed resource allocation scheme achieves lower packet collision probability and higher resource utilization ratio when compared with the uniform resource allocation scheme.
基金Supported by the National High Technology Research and Development Program of China (No. 2006AA01Z280,2007AA01 Z278).
文摘We propose a novel vertical Bell Laboratories layered space-time (V-BLAST) based two-way relayingprotocol that comprises two user terminals and one multi-antenna demodulate-and-forward (DMF) relaystation. We consider the situation when these two user terminals employ different modulation types andinvestigate its detection techniques. The key feature of the detection techniques is that we quantify decisionreliability at the relay station by introducing a so-called normalized correlation coefficient (CORR),rather than having full confidence in demodulation at the relay station. With the assistance of the normalizedconelation coefficient, we develop detection methods at both the relay station and user terminals. Inparticular, we propose a CORR-based ordering algorithm at the relay station which can be applied to detectionfor general V-BLAST architectures. Simulation results demonstrate the superiority of the CORR-basedordering algorithm over the conventional signal-to-noise based ordering algorithm. Finally, wedemonstrate overall error-performance of the V-BLAST-based DMF two-way relaying protocol via simulations.
