Design and Performance Analysis of Multisatellite Cooperative Transmission Based on Orthogonal Carrier Aggregation

ABSTRACT With the continuous growth of satellite communication traffic and user access demands, the limited bandwidth capacity of a single satellite is insufficient to support the scalable broadband access demands of video services. To address this challenge, this paper proposes a multisatellite cooperative distributed orthogonal carrier aggregation (CA). By dynamically allocating satellite spectrum resources to orthogonal subcarriers and combining signals at the ground terminal, the system bandwidth is significantly enhanced. Employing a guard‐interval‐free design, the scheme relies on precise synchronization and Doppler precompensation to achieve seamless orthogonal CA, effectively avoiding spectrum waste, suppressing interference, and maximizing spectral efficiency. In response to the key technical challenges in cooperative transmission, this paper focuses on studying symbol timing synchronization and frequency synchronization algorithms for multilink scenarios. To validate the practical performance of the scheme, a dual‐satellite cooperative transmission simulation system with a signal bandwidth of 5 MHz was established, and QPSK modulation was adopted for testing. Simulation results demonstrate that at a bit error rate (BER) of 10 −3 , the signal‐to‐noise ratio (SNR) gains under ideal synchronization conditions (without timing and frequency impairments) reach 3 and 2.7 dB in AWGN and NTN‐TDL‐D channels, respectively. Even when channel impairments such as Doppler frequency offset and link delay are introduced, the system still maintains SNR gains of 2.75 and 2.5 dB after precompensation at the transmitter based on the proposed algorithm. These results significantly validate the effectiveness and robustness of the proposed scheme in complex satellite‐terrestrial communication scenarios.