| dc.description.abstract | With advancements in radio frequency (RF) components and antenna technologies, Low Earth Orbit (LEO) satellite communications based on Massive Multiple-Input Multiple-Output (Massive MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) are becoming increasingly prevalent in the B5G era characterized by vast bandwidths. This technology has garnered significant attention due to its ability to support high data transmission rates while substantially reducing hardware costs, positioning it as one of the most promising technologies for future networks. This paper focuses on designing subcarrier allocation and user selection schemes for multi-user (MU) Massive MIMO OFDM LEO satellite communication systems with the objective of maximizing the total uplink system transmission rate. The optimization is performed while ensuring that each user’s Quality of Service (QoS) requirements, such as bit error rate and data transmission rate, are met.
For subcarrier allocation, we employ a Lagrangian optimization method to efficiently distribute subcarriers, thereby enhancing spectral efficiency. This approach considers the spectral utilization and power allocation of each subcarrier to achieve optimal configuration within the total power constraints. In terms of user selection, we utilize Singular Value Decomposition (SVD) on each user′s channel matrix across subchannels, prioritizing users with superior channel conditions from a pool of candidates for data transmission. This user selection strategy effectively improves the overall system performance and spectral utilization.
During the transmission process, signals at different frequencies may experience varying degrees of attenuation, multipath interference, and distortion, leading to differences in channel frequency responses. To counteract frequency-selective fading, Orthogonal Frequency Division Multiplexing (OFDM) is widely applied. Additionally, the Lagrangian method is not only used for subcarrier allocation but also for power distribution, ensuring that the transmission needs of all users are satisfied in a multi-user environment.
In summary, we evaluate the performance of the proposed subcarrier allocation and user selection schemes under various parameters and compare them with other benchmark schemes. Simulation results demonstrate that the proposed subcarrier allocation and SVD-based user selection schemes achieve highly competitive performance, surpassing traditional fully digital designs in terms of total transmission rate and spectral efficiency. Furthermore, iterative adjustments to the original data stream configurations enhance the overall spectral efficiency. | en_US |