Hybrid DSB-SSB Modulation for SGLS Bandwidth Compression
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Solution Overview
Problem
The transition of the 1695-1710 MHz and 1755-1780 MHz bands for commercial mobile broadband usage poses operational challenges and interference risks for the Air Force Satellite Control Network's SGLS, requiring solutions that enhance spectrum efficiency and minimize interference.
Innovation Solution
A hybrid modulation and demodulation system that combines double sideband (DSB) and single sideband (SSB) modulation techniques for the space-ground link system, allowing for reduced bandwidth and improved spectrum efficiency without hardware upgrades, using a transmitter to generate a hybrid waveform and a receiver to demodulate signals effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If standard DSB modulation is used for SGLS transmission, then hardware consistency is maintained, but bandwidth is excessive and spectrum efficiency is poor
Solution Approach 1:
The hybrid signal is segmented into two separate components: a first component modulated using DSB and a second component modulated using SSB. This segmentation allows each component to be optimized for its specific requirements, with the SSB component providing bandwidth efficiency and the DSB component maintaining hardware compatibility, thereby resolving the contradiction between bandwidth reduction and spectrum efficiency.
Solution Approach 2:
Different modulation schemes are applied to different components of the hybrid signal based on their specific requirements. The first component uses DSB modulation to maintain hardware consistency, while the second component uses SSB modulation to achieve bandwidth efficiency. This local differentiation of modulation quality allows the system to optimize overall spectrum efficiency without sacrificing hardware compatibility.
2Quantity of substance
If SSB modulation is used to reduce bandwidth, then spectrum efficiency improves, but hardware compatibility issues arise
Solution Approach 1:
The patent merges DSB and SSB modulation techniques into a hybrid modulation scheme. By combining the advantages of both modulation types in a single system, the invention achieves bandwidth efficiency from SSB while maintaining hardware compatibility through the DSB component, thus resolving the contradiction between bandwidth reduction and hardware adaptability.
Solution Approach 2:
The hybrid modulation system performs multiple functions simultaneously: it provides bandwidth efficiency through SSB modulation of the second component while maintaining hardware compatibility through DSB modulation of the first component. This multi-functionality allows the system to adapt to both bandwidth constraints and existing hardware infrastructure.
3Object-affected harmful factors
If spectrum compression is implemented to share bands with commercial mobile broadband, then interference to neighboring bandwidth is minimized, but system complexity increases
Solution Approach 1:
The signal is segmented into two components with different modulation schemes, allowing selective optimization for interference minimization. The SSB-modulated second component provides spectral efficiency and reduced interference to neighboring bands, while the DSB-modulated first component maintains simplicity in certain aspects, thereby managing system complexity while minimizing interference.
Solution Approach 2:
The system changes modulation parameters by applying different modulation schemes (DSB and SSB) to different signal components. This parameter differentiation allows the system to achieve spectrum compression and minimize interference to commercial mobile broadband bands while managing complexity through structured signal processing.
Data Source
AI summary
A system for hybrid modulation and demodulation includes a transmitter and a receiver. The transmitter is configured to receive a hybrid signal of a space-ground link system (SGLS), including a first component and a second component; perform a double sideband (DSB) modulation on the first component using a carrier frequency to obtain a first waveform; perform a single sideband (SSB) modulation on the second component using the carrier frequency to obtain a second waveform; mix the first waveform and the second waveform to generate a hybrid waveform; and transmit the hybrid waveform. The receiver is configured to receive the hybrid waveform; determine the carrier frequency; separate the first waveform and the second waveform; perform a DSB demodulation on the first waveform to obtain a first demodulated signal; and perform an SSB demodulation on the second waveform to obtain a second demodulated signal.