Dual-Polarization D2D Satellite Receive Links Without Dual RF Chains
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Solution Overview
Problem
Dual circular polarization antennas for D2D communication are costly due to the need for double RF chains, while single polarization antennas result in reduced performance, necessitating an improved system and method for D2D communication.
Innovation Solution
A system utilizing 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 optimizing signal reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dual circular polarization antennas are used for D2D communication, then reception gain is maximized, but cost increases almost two times due to doubled RF chains
Solution Approach 1:
The patent segments the dual polarization reception function across two separate satellites instead of implementing it in a single satellite. Each satellite carries only one circular polarization antenna (LHCP or RHCP), halving the RF chain requirements per satellite while maintaining dual polarization capability through spatial distribution and signal recombination at the ground segment.
Solution Approach 2:
The ground segment acts as an intermediary that receives signals from both satellites, performs digital signal processing to separate and recombine the LHCP and RHCP components, and reconstructs the full dual polarization signal. This transfers the complexity from space (satellites) to ground, allowing simplified satellite designs.
2Device complexity
If single circular polarization antennas are used in satellite constellation, then cost is reduced, but D2D performance is significantly reduced
Solution Approach 1:
The patent moves from a single-satellite architecture to a multi-satellite constellation, adding the spatial dimension to the system. By distributing LHCP and RHCP receiving capabilities across different satellites in the constellation, the system achieves dual polarization performance without requiring each individual satellite to have complex dual polarization antennas.
Solution Approach 2:
The ground segment merges the signals received from multiple satellites, combining the LHCP signal from one satellite with the RHCP signal from another satellite to reconstruct the complete dual polarization signal, thereby achieving high D2D performance with simplified single-polarization satellite antennas.
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 provides significant cost savings and improved reception gain by using single polarization DRAs, while maintaining performance comparable to dual polarization systems, with potential mass and design improvements.
Implementation Method 1
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
Implementation Method 2
transmit the first digital signal via an optical intersatellite link (OISL)
Implementation Method 3
receive the RF signal in left handed circular polarization (LHCP) or right hand circular polarization (RHCP)
Data Source
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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.