Pragmatic M-MIMO Beamforming for Satellite Payload Complexity Reduction
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Solution Overview
Problem
Current satellite communication systems face challenges in implementing Massive Multiple-Input Multiple-Output (M-MIMO) technology due to high complexity, co-channel interference, and the need for user feedback, particularly in broadband satellite networks with geostationary and non-geostationary orbits, where conventional precoding techniques are less effective.
Innovation Solution
A method for wireless communications using pragmatic M-MIMO or optimized Color Frequency Reuse (CFR) techniques, which involve selecting subsets of user terminals based on their geographical locations and determining beam centers for active beams, allowing for efficient beamforming without user feedback, thereby reducing co-channel interference and achieving quasi-optimum throughput with simplified system complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional precoding techniques are implemented in satellite communication systems, then M-MIMO performance can be achieved, but system complexity and payload complexity increase significantly
Solution Approach 1:
The patent extracts the precoding function from the satellite payload and relocates it to ground-based hub stations. This allows the satellite payload to remain simple while achieving M-MIMO performance through ground-based signal processing. The hub station performs all complex precoding operations, and the satellite simply transmits the pre-coded signals.
Solution Approach 2:
The patent introduces ground-based hub stations as intermediary nodes between the satellite and user terminals. These hub stations perform channel estimation, precoding calculations, and signal processing, acting as a mediator that enables M-MIMO functionality without requiring complex onboard processing at the satellite.
2Device complexity
If precoding is implemented at separated gateways to reduce payload complexity, then payload complexity decreases, but co-channel interference mitigation becomes less effective
Solution Approach 1:
The patent merges multiple gateway functions into a coordinated multi-hub station system. Multiple hub stations work together with centralized coordination to perform joint precoding, which maintains effective co-channel interference mitigation while distributing the implementation across multiple ground-based locations rather than requiring complex onboard processing.
3Productivity
If precise channel estimation is performed to improve precoding accuracy, then throughput increases, but the need for user feedback and channel reporting increases system complexity
Solution Approach 1:
The patent implements self-service channel estimation where the hub station autonomously estimates channels by analyzing uplink signals from user terminals. This eliminates the need for complex downlink channel estimation and user feedback mechanisms, as the hub station independently determines channel conditions and adjusts precoding accordingly.
4Object-affected harmful factors
If beamforming is used to reduce co-channel interference, then interference mitigation improves, but the need for precise beam control increases payload complexity
Solution Approach 1:
The patent extracts beamforming control functions from the satellite payload and implements them at ground-based hub stations. The satellite payload only needs to transmit signals with basic beam patterns, while all complex beamforming calculations, phase adjustments, and amplitude control are performed ground-based, significantly reducing payload complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed method enables efficient M-MIMO performance with reduced system and payload complexity, achieving high throughput and capacity in satellite communication networks while minimizing co-channel interference and eliminating the need for user feedback.
Implementation Method 1
transmitting radio signals to subsets of user terminals among the plurality of user terminals with sets of active beams
Data Source
AI summary
This application relates to a method of performing wireless communications between a hub station and a plurality of user terminals. The method comprises transmitting radio signals to subsets of user terminals among the plurality of user terminals with sets of active beams, wherein the active beams have beam centers that are determined based on locations of the user terminals. The method further comprises, for each of a plurality of radio resource blocks: selecting a subset of user terminals among the plurality of user terminals; for each user terminal among the subset of user terminals, determining a beam center based on a location of the respective user terminal; and transmitting, using the respective radio resource block, radio signals to the user terminals among the selected subset of user terminals, in beams corresponding to the determined beam centers. The method further relates to a corresponding hub station for performing wireless communications with a plurality of user terminals, and to a method of determining antenna parameters and a beam pattern for a hub station.