Author
Gao Xiqi
Bio: Gao Xiqi is an academic researcher. The author has contributed to research in topics: Optimization problem & Telecommunications link. The author has an hindex of 1, co-authored 1 publications receiving 1 citations.
Papers
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Patent•
05 Jun 2020
TL;DR: In this paper, a large-scale MIMO satellite mobile communication downlink transmission system with maximum reachability and rate was proposed. But the authors focused on the downlink precoding vector design problem, which was converted into a multi-times convex optimization sub-problem.
Abstract: The invention discloses a large-scale MIMO satellite mobile communication downlink transmission method and a large-scale MIMO satellite mobile communication downlink transmission system with maximum reachability and rate. A satellite or a gateway station calculates a precoding vector corresponding to each user terminal through an iterative algorithm by using statistical channel information of eachuser terminal according to traversal reachability and rates of all users or an upper bound maximization criterion of all the users; downlink precoding transmission is carried out by using the obtained vector. According to the iterative algorithm, a precoding vector design problem is converted into a multi-times convex optimization sub-problem, a precoding vector is obtained by iteratively solvingthe convex optimization sub-problem, or the convex optimization sub-problem is converted into a Lagrange multiplier optimization problem, a Lagrange multiplier is iteratively solved, and then the precoding vector is calculated. And the user terminal performs frequency and time compensation on a received signal by utilizing Doppler frequency shift caused by satellite movement and minimum propagation time delay of long-distance propagation. According to the invention, the reachability and rate performance of a satellite mobile communication system can be improved, and the calculation complexityis relatively low.
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Patent•
04 Dec 2020
TL;DR: In this article, a satellite large-scale MIMO (Multiple Input Multiple Output) wide-coverage precoding transmission method was proposed, which utilizes precoding to generate a widecoverage power pattern and can solve the power coverage problem of large scale public signal transmission of a low earth orbit satellite.
Abstract: The invention discloses a satellite large-scale MIMO (Multiple Input Multiple Output) wide-coverage precoding transmission method, which utilizes precoding to generate a wide-coverage power pattern and can solve the power coverage problem of large-scale MIMO public signal transmission of a low earth orbit satellite. The method comprises the following steps: calculating an angle range covered by apower pattern based on a triangular geometrical relationship by utilizing information such as the height of a satellite above the sea level and the average radius of the earth; constructing an optimization problem by taking the minimum and maximum improved Cramer-Rao bound as a target and taking the equal transmitting power of each antenna as a constraint condition; and solving a precoding matrixbased on a non-monotonic conjugate gradient method on the manifold. According to the invention, the capacity of the satellite power amplifier can be fully utilized, and the average receiving power andthe minimum receiving power in the coverage range are high.