Robust transmission method for multicast and multibeam satellite mobile communication systems

Abstract

The invention proposes a robust transmission method suitable for a multicast multi-beam satellite mobile communication system. The method includes the following steps: firstly, considering the channellong delay characteristics in a satellite mobile communication system, and performing user grouping based on an average Euclidean distance criterion in the case that a gateway station only knows partof the channel information; and then, considering the characteristics that the channel amplitude remains basically unchanged and the channel phase changes rapidly during the long delay, adopting a random variable to characterize the channel phase uncertainty caused by the channel state information feedback delay, calculating a mathematical expectation of a signal-to-interference-to-noise ratio (SINR) of a user with respect to the random variable to obtain an average SINR, and further modeling a precoding problem as a power minimization problem; and finally, solving the power minimization problem by using semi-definite relaxation and Gaussian randomization methods to obtain an optimal precoding vector for each user group. Compared with a conventional method that does not consider the outdated channel information, the robust transmission method proposed by the invention can significantly improve the system performance.

Description

technical field [0001] The invention relates to a transmission method of a satellite wireless communication system, in particular to a robust transmission method suitable for a multicast multi-beam satellite mobile communication system. Background technique [0002] In view of the high-throughput data rate requirements of next-generation satellite mobile communication systems, satellites generally adopt a multi-beam system framework, and multiple beams serve terminals in a wide coverage area. Compared with the single-beam mobile satellite communication system, the multi-beam mobile satellite communication system has greater throughput and higher spectrum utilization. Due to the radiation characteristics of the antenna, beam side lobes are difficult to eliminate, and there are often overlapping coverage areas between adjacent beams. Users in this area will suffer severe inter-beam interference. Therefore, most existing satellite mobile communication systems use multi-color co...

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Problems solved by technology

[0003] In practical application, the traditional transmission method will be limited by various conditions: First, in the existing satellite standards such as DVB-S2 and DVB-S2X, the satellite encapsulates the data transmitted to multiple users in the same frame , in this scenario, a precoding vector in the precoding matrix no longer corresponds to a user, but corresponds to a user group, so on the one hand, the precoding problem needs to be modeled as a multi-group multicast optimization problem, and on the other On the one hand, designing a reasonable user grouping algorithm is also particularly important; second, it is difficult to achieve power sharing between beams on satellites, so it is necessary to consider the single-antenna power constraint; third, in satellite mobile communication systems, high transmission delay makes It is difficult for the sender to obtain accurate channel information

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