Ground-Based Beam Former for Satellite Link Performance
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Solution Overview
Problem
Multibeam satellite systems face significant co-channel interference (CCI) challenges, particularly with small terminals and mobile devices, which affect link closure, data rate, and quality of service due to geographic proximity and omnidirectional antennas, leading to severe CCI issues at the edge of co-channel cells.
Innovation Solution
A ground-based beam former (GBBF) is employed to improve signal-to-noise ratio (SNR) by beamforming and processing signals from multiple satellites, including remnant signals, to mitigate CCI and enhance link performance and availability through beam and satellite diversity, using amplitude and phase offsets to form directional spot beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If frequency reuse is employed in multibeam satellite systems, then bandwidth efficiency is improved, but co-channel interference increases at the edge of co-channel cells
Solution Approach 1:
The patent segments the satellite coverage area into multiple beams with different polarizations (horizontal and vertical). Each beam serves a specific service area, and the segmentation allows frequency reuse while managing interference through spatial and polarization separation. The ground-based beam former further segments and processes signals from different beams to mitigate interference at cell edges.
Solution Approach 2:
The patent applies different polarization characteristics to different beams serving adjacent service areas. By assigning orthogonal polarizations (horizontal/vertical) to co-channel beams, the system creates local quality differences that enable frequency reuse. The ground-based beam former also applies local processing to extract and combine signals specifically for users at the edge of service areas.
2Adaptability or versatility
If small terminals with omnidirectional antennas are used, then device portability is improved, but link closure capability deteriorates due to low transmission power and severe CCI
Solution Approach 1:
The ground-based beam former acts as an intermediary between the satellite and the small terminal. It receives signals from multiple satellite beams, processes them through beamforming operations, and combines them to provide enhanced signal quality to the terminal. This intermediary processing compensates for the terminal's low transmission power and omnidirectional antenna limitations.
Solution Approach 2:
The patent merges signals from multiple satellite beams (including primary and adjacent beams) at the ground-based beam former. By combining these signals with appropriate weighting and phase adjustment, the system creates a composite signal with improved signal-to-noise ratio that compensates for the small terminal's limited transmission capabilities.
3Reliability
If ground-based beam forming is implemented, then signal-to-noise ratio is improved by 3 to 6 dB, but system complexity increases
Solution Approach 1:
The ground-based beam former performs self-calibration and adaptive beamforming operations to optimize signal reception. The system automatically adjusts beam weights, phases, and amplitudes based on received signal characteristics, reducing the need for manual configuration and external intervention while maintaining high signal-to-noise ratio performance.
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 GBBF system achieves a 3 to 6 dB improvement in SNR for user terminals, especially at the edge of service areas, by magnifying desired signals and suppressing interference, thereby improving link performance and availability in satellite networks.
Implementation Method 1
GBBF mitigates CCI by introducing amplitude and phase offsets into the paths prior to sending to a feeder channel to the on-board feed elements to form the directional spot beams
Data Source
AI summary
A method and system for improving link performance for a user terminal (UT) in a satellite network is disclosed. The method including: providing a first beam servicing a first service area that is adjacent a second service area serviced by a second beam; transmitting, from the first service area, a transmission via the first beam to a receiver via a satellite; beamforming the first beam and the second beam at the receiver; extracting the first beam and a remnant signal of the first beam from the second beam; and processing the first beam and the remnant signal to receive the transmission, wherein the remnant signal may include a portion of the transmission received by a second beam antenna of the satellite.