Dynamic Sub-Array Precoding for LEO Satellite MIMO Capacity
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Solution Overview
Problem
In MIMO wireless communication systems using LEO satellites that are constantly moving and in a line-of-sight environment, high channel correlation leads to reduced channel capacity and communication line stability, along with increased peak-to-average power ratio (PAPR) due to eigenmode transmission.
Innovation Solution
A wireless communication system and method that involves estimating channel information, deriving all combinations of sub-array configurations, calculating channel capacity, selecting an optimal precoding matrix, and performing in-phase combining to maximize channel capacity while suppressing PAPR increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If eigenmode transmission with precoding is used to increase channel capacity, then channel capacity is improved, but peak-to-average power ratio (PAPR) increases causing signal distortion
Solution Approach 1:
The patent applies dynamics by making the sub-array configuration changeable rather than fixed. The system dynamically adjusts the sub-array configuration based on channel conditions to optimize performance. This allows the system to adapt to varying channel states while maintaining low PAPR, resolving the contradiction between achieving high channel capacity and preventing signal distortion from excessive PAPR.
Solution Approach 2:
The patent changes the parameter of sub-array configuration from fixed to variable. By allowing the sub-array configuration to be adjusted according to channel conditions, the system can optimize the balance between channel capacity and PAPR control. This parameter change enables the system to achieve high capacity when conditions permit while maintaining low PAPR to prevent distortion when needed.
2Reliability
If a fixed sub-array configuration is used to suppress PAPR increase, then transmission quality is improved, but channel capacity and adaptability are reduced
Solution Approach 1:
The patent transforms the fixed sub-array configuration into a dynamic one that can be adjusted based on channel conditions. This allows the system to maintain transmission quality by suppressing PAPR when needed while also being able to increase channel capacity when channel conditions allow. The dynamic adjustment capability resolves the contradiction between reliability and productivity.
Solution Approach 2:
The system changes the sub-array configuration parameter from static to variable, enabling it to adapt to different channel conditions. When channel conditions are favorable, the configuration can be adjusted to maximize capacity; when conditions are poor, it can be adjusted to maintain quality by suppressing PAPR. This parameter flexibility resolves the trade-off between transmission quality and channel capacity.
3Productivity
If more antennas are installed to perform eigenmode transmission, then channel capacity is increased, but device complexity and power consumption increase
Solution Approach 1:
The patent applies segmentation by dividing the antenna array into multiple sub-arrays. Instead of using all antennas simultaneously for eigenmode transmission, the system segments the antennas into smaller sub-arrays that can be independently configured. This reduces the effective number of antennas needed at any given time, thereby reducing device complexity and power consumption while still achieving high channel capacity through optimized sub-array configurations.
Solution Approach 2:
The patent changes the operational parameter from using all antennas to using a variable number of antennas organized in sub-arrays. By adjusting the sub-array configuration, the system can achieve high channel capacity with fewer actively used antennas, reducing device complexity and power consumption requirements while maintaining productivity.
4Productivity
If eigenmode transmission is used to accommodate more terminals, then communication capacity is increased, but PAPR increases causing distortion in output signals
Solution Approach 1:
The patent applies dynamics by making the sub-array configuration adjustable based on communication conditions. This allows the system to accommodate more terminals and increase communication capacity while dynamically controlling the PAPR to prevent signal distortion. The dynamic configuration enables the system to adapt to the number of active terminals and optimize performance without excessive PAPR.
Solution Approach 2:
The patent changes the sub-array configuration parameter to enable flexible accommodation of varying numbers of terminals. By adjusting the configuration based on the number of active terminals and channel conditions, the system can increase communication capacity while maintaining PAPR within acceptable limits to prevent distortion. This parameter flexibility resolves the contradiction between capacity and distortion prevention.
Data Source
AI summary
The transmitting station or the receiving station estimates channel information. All combinations of sub-array configurations in accordance with the number of transmitting antennas, the number of receiving antennas, and the number of transmission signals are derived. For the all combinations, precoding matrices which can be combined in-phase with the selected receiving antennas are derived. The channel capacity for the all combinations from the channel information and the precoding matrix is calculated. The optimal precoding matrix which maximizes channel capacity is selected. The transmission-side control information is determined from the optimal precoding matrix. The transmitting station switches the output destination of a single signal or a plurality of signals on the basis of the transmission-side control information and forms an arbitrary sub-array corresponding to each signal. The sub-array performs in-phase combining using phase control for the desired receiving antenna. The receiving station combines, separates, and demodulates the signals.