Repetition Coded Satellite Signal Hierarchical Modulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Receiver performance in satellite-based communications systems is hindered by noise, particularly in multi-level transmission schemes, where existing technologies do not effectively enhance signal-to-noise ratio (SNR) for legacy receivers to decode additional services.
Innovation Solution
Incorporating a repetition coder in the transmitter to repeat at least one level of the multi-level modulated signal and a modulator to provide a multi-level transmission signal, along with a unified receiver that includes a repetition decoder for decoding the received signal, allowing for hierarchical or layered demodulation modes to improve performance in noisy environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multi-level modulation is used to provide additional services to legacy receivers, then system adaptability is improved, but receiver performance in noisy environments deteriorates
Solution Approach 1:
The patent segments the modulation signal into multiple levels (first level and second level) where the first level contains legacy services and the second level contains additional services. This segmentation allows legacy receivers to decode only the first level while new receivers can decode both levels, thereby maintaining system adaptability while improving receiver performance through selective decoding capabilities.
Solution Approach 2:
The patent implements a nested modulation structure where the second level signal is modulated onto the first level signal, creating a multi-level modulation scheme. This nesting allows the additional services to be embedded within the legacy signal structure, enabling legacy receivers to access their services while new receivers can extract additional services without degrading overall receiver performance.
2Reliability
If repetition coding is applied to at least one level of the multi-level modulated signal, then signal-to-noise ratio is improved, but data rate decreases
Solution Approach 1:
The patent applies repetition coding selectively to at least one level of the multi-level modulated signal rather than to all levels. This partial application of repetition coding improves the signal-to-noise ratio for the coded level while minimizing the impact on overall data rate. The system can choose to repeat coding only the more vulnerable levels or adjust the repetition factor based on channel conditions.
3Adaptability or versatility
If a unified receiver with multiple demodulation modes is implemented, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent implements a unified receiver that can operate in multiple demodulation modes (first demodulation mode for legacy services and second demodulation mode for additional services). This multi-functional receiver design allows a single device to adapt to different service requirements and signal conditions, improving receiver adaptability while managing complexity through a unified architecture that handles multiple functions.
Data Source
AI summary
A satellite communications system comprises a transmitter, a satellite transponder and a receiver. The transmitter transmits an uplink multi-level modulated signal (hierarchical modulation or layered modulation) to the satellite transponder, which broadcasts the multi-level modulated signal downlink to one, or more, receivers. The transmitter includes a repetition coder for repetition coding at least one level, e.g., a lower level, of the multi-level modulated signal. In complementary fashion, the receiver includes a repetition decoder for use in decoding the at least one repetition coded level of the received multi-level modulated signal.