You Li

Bio: You Li is an academic researcher. The author has contributed to research in topics: Communications satellite & Precoding. The author has an hindex of 1, co-authored 2 publications receiving 2 citations.

High-energy-efficiency robust precoding method suitable for multi-beam satellite communication system

Abstract: The invention provides a high-energy-efficiency robust precoding method suitable for a multi-beam satellite communication system The method comprises the following steps: firstly, considering a channel propagation long delay characteristic in a satellite communication system, and representing channel phase uncertainty caused by channel state information feedback delay and the like by using a random variable; secondly, considering the characteristic of limited energy of the satellite communication system, solving mathematical expectation of the user rate about the random variables, dividing the minimum value in the user group by the total power consumption of the group to obtain the energy efficiency of the user group, and modeling a robust precoding design problem as a total power minimization problem under the constraint of the energy efficiency of the user group; and finally, converting an initial total power minimization problem into a series of convex optimization sub-problems foriterative solution through a positive semidefinite relaxation and sequential optimization method, and obtaining a precoding vector of each user group by adopting a Gaussian randomization method Compared with a traditional precoding method, the high-energy-efficiency robust precoding method provided by the invention has the advantage that the performance and the energy efficiency of a multi-beamsatellite communication system can be remarkably improved

Low-complexity large-scale MIMO low-orbit satellite precoding method

Abstract: The invention provides a low-complexity large-scale MIMO downlink precoding method in a low-orbit satellite communication system, a large-scale uniform planar antenna array is configured on a satellite side, a satellite groups users by using space angle information of each user, and the users in the same group are scheduled to use the same time-frequency resource to perform wireless communicationwith the satellite. A downlink precoding vector of each user is calculated by utilizing the statistical channel state information at the satellite side. Based on a truncated Taylor polynomial expansion theory, complex large-dimension matrix inversion operation in a downlink precoding vector is replaced by the sum of finite term matrix polynomials, so that the calculation complexity of the precoding vector is reduced. A matrix polynomial is iteratively calculated by adopting a Horner algorithm in calculation, so that the calculation complexity of the matrix polynomial is reduced. The final sumrate performance of the method provided by the invention can effectively approach the performance of downlink maximum signal-to-leakage-and-noise ratio precoding at a low expansion order.

Multi-beam satellite communication robust precoding method for balancing total energy efficiency and minimum energy efficiency

Abstract: The invention discloses a multi-beam satellite communication robust pre-coding method capable of balancing total energy efficiency and minimum energy efficiency, which is characterized in that randomvariables are introduced to represent channel phase uncertainty caused by channel state information feedback delay and the like, and optimal balancing of a multi-target problem is realized in a form of weighted product of total energy efficiency and minimum energy efficiency. According to the method, the robust precoding design problem of multi-target energy efficiency balance is modeled into theproblem of maximization of the weighted product of the total energy efficiency and the minimum energy efficiency under the constraint of the total power. The method comprises the following steps: converting the initial total energy efficiency and minimum energy efficiency trade-off problem into a series of iteratively solved convex optimization sub-problems through a positive semidefinite relaxation and sequential optimization method, and finally obtaining an optimal pre-coding vector through eigenvalue decomposition based on the rank of the solution or obtaining a suboptimal pre-coding vectorthrough a Gaussian randomization method. According to the invention, the balance between fairness and the overall energy efficiency performance of the system can be realized, and the performance andthe energy efficiency of the multi-beam satellite communication system can be significantly improved compared with the traditional precoding method.

Satellite large-scale MIMO wide-coverage precoding transmission method

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.