Robust precoding method of multi-beam satellite communication system based on outage probability constraint

Abstract

The invention discloses a robust precoding method of a multi-beam satellite communication system based on outage probability constraint. The method comprises the following steps: firstly, consideringthe channel long delay characteristics in the satellite mobile communication system, using random variables to characterize the channel phase uncertainty caused by the channel state information feedback delay and the like, and modelling a robust precoding problem as a power minimization problem based on the outage probability constraint in accordance with the channel model; then, converting a probability constraint condition into a low-complexity approximate representation form that is convenient to solve based on the central-limit theorem and the Gaussian distribution; and finally, convertingthe initial power minimization problem into a convex optimization problem through positive semidefinite relaxation, and obtaining a precoding vector of each user group by using a Gaussian randomization method. Compared with the traditional transmission method in which the channel information uncertainty is not considered, the robust transmission method based on the outage probability constraint proposed by the invention has the advantages of greatly reducing the transmission outage probability and improving the transmission performance of the multi-beam satellite communication system.

Description

technical field [0001] The invention relates to a precoding method for a satellite wireless communication system, in particular to a robust precoding method for a multi-beam satellite communication system based on outage probability constraints. Background technique [0002] Compared with single beam, multi-beam has become the development trend of the next generation mobile satellite communication system due to its significantly improved system throughput. In multi-beam satellites, how to reduce inter-beam interference is an urgent problem to be solved. In order to improve the spectrum efficiency of the system, the traditional frequency reuse method is no longer applicable, and the same-frequency networking has become a research hotspot. In a multi-beam satellite mobile communication system that adopts the same-frequency networking, the purpose of reducing inter-beam interference can be achieved by performing multi-beam joint precoding at the transmitter. [0003] In multi...

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Problems solved by technology

Compared with the other two, the precoding method based on outage probability constraints ensures more reliable system gain by setting probability thresholds, but because the probability constraints often have no simple closed-form expression and have high computational complexity, Therefore, it is necessary to find a low-complexity approximation that is easy to solve to represent

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