Dual-Polarization D2D Receive Links Using Alternating Satellite Polarization
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Solution Overview
Problem
Dual circular polarization arrays in satellite communications are costly due to the need for double RF chains, while single polarization arrays result in reduced performance for direct-to-device (D2D) communication.
Innovation Solution
A system using a satellite constellation with single polarization receive DRAs and alternating polarization between two spacecraft, where signals are received by opposite circular polarization antennas and recombined to achieve higher gain, reducing the need for multiple RF chains and improving performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dual circular polarization arrays are used to maximize reception gain for linearly polarized mobile devices, then reception performance is improved, but system cost increases significantly due to the need to double all RF chains
Solution Approach 1:
The patent divides the dual polarization function across multiple satellites instead of implementing it on a single satellite. Each satellite carries only single circular polarization antennas (either LHCP or RHCP), but the constellation collectively provides both polarizations through spatial distribution, eliminating the need to double RF chains on each satellite
Solution Approach 2:
The patent combines signals from multiple satellites with different polarizations at the ground station. The signal processing system merges LHCP and RHCP signals received from different satellites to reconstruct the complete dual polarization signal, achieving dual polarization performance without dual polarization hardware on each satellite
2Device complexity
If single circular polarization antennas are used to reduce cost, then system cost decreases, but reception performance is significantly reduced compared to dual polarization
Solution Approach 1:
The patent transitions from a single-satellite approach to a multi-satellite constellation approach, adding the spatial dimension to the polarization reception. By distributing satellites with different polarizations across the sky, the system achieves dual polarization capability through spatial diversity rather than through hardware duplication on each satellite
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
This approach allows for significant cost savings and improved reception gain by using single polarization DRAs with signal recombination, maximizing performance while minimizing the number of RF chains and satellite components.
Implementation Method 1
transmit the first digital signal via an optical intersatellite link (OISL)
Implementation Method 2
receive the RF signal in left handed circular polarization (LHCP) or right hand circular polarization (RHCP)
Data Source
AI summary
Provided is a system and method for direct-to-device (D2D) communication. The system includes a user device for transmitting a radio frequency (RF) signal in linear polarization and a satellite constellation including a first satellite, and a second satellite. The first satellite is configured to receive the RF signal in left handed circular polarization (LHCP) or right hand circular polarization (RHCP), convert the received RF signal to a first digital signal, and transmit the first digital signal via an optical intersatellite link (OISL). The second satellite is configured to receive the RF signal in an opposite polarization of the first satellite, convert the received RF signal to a second digital signal, receive the first digital signal via the OISL, and recombine the first digital signal and the second digital signal.