Satellite Modulation and Coding Schemes for Extended Es/N0 Range
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Solution Overview
Problem
Current modulation and coding schemes, such as the DVB-S2 standard, are inadequate for supporting terminals with operational requirements at low signal-to-noise ratios (Es/N0) below −3 dB and high Es/N0 ratios above 15.5 dB, and lack sufficient granularity within the intermediate range of −3 dB to 15.5 dB for satellite communications.
Innovation Solution
The development of new modulation and coding schemes that support terminals with Es/N0 ratios from approximately −3 dB to −10 dB and 15.5 dB to 24 dB, and provide finer granularity within the intermediate range, using advanced encoding methods like Low Density Parity Check (LDPC) codes and novel signal constellations like 256-APSK with a 32+32+64+64+64 ring format.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current DVB-S2 modulation and coding schemes are used, then operation is supported down to Es/N0 ratios of about −3 dB, but operation below −3 dB (down to −9 dB to −10 dB) cannot be supported
Solution Approach 1:
The patent segments the signal constellation into multiple rings (e.g., 5 rings for 256-APSK with 32+32+64+64+64 points per ring) rather than using a single uniform constellation. This segmentation allows different rings to be activated based on channel conditions, enabling operation at lower Es/N0 ratios while maintaining adaptability across different signal conditions
Solution Approach 2:
The patent introduces new modulation parameters including multiple APSK constellations with different ring configurations (16-APSK, 32-APSK, 64-APSK, 256-APSK) and new code rates (e.g., 11/15, 13/15, 29/36, 31/36). These parameter changes expand the coverage range from −3 dB to −10 dB and beyond 15.5 dB while maintaining DVB-S2 compatibility
2Adaptability or versatility
If current DVB-S2 modulation and coding schemes are used, then operation is supported up to Es/N0 ratios of about 15.5 dB, but operation above 15.5 dB cannot be supported
Solution Approach 1:
The patent implements dynamic selection of modulation and coding parameters based on channel conditions. The system can dynamically switch between different APSK constellations and code rates to adapt to varying Es/N0 ratios, enabling operation from −10 dB up to 24 dB and beyond by selecting appropriate parameters for each operating condition
Solution Approach 2:
The patent introduces higher-order modulations (64-APSK, 256-APSK) and extended code rates (e.g., 31/36, 25/36) that enable operation at high Es/N0 ratios above 15.5 dB. These parameter changes provide the necessary granularity and performance headroom for high signal-to-noise ratio environments while maintaining compatibility with the DVB-S2 framework
3Adaptability or versatility
If current DVB-S2 modulation and coding schemes are used, then coverage is provided for Es/N0 ratios from −3 dB to 15.5 dB, but sufficient granularity is lacking for intermediate ranges
Solution Approach 1:
The patent segments the modulation space into multiple APSK constellations with different ring structures (16-APSK, 32-APSK, 64-APSK, 256-APSK) and divides code rates into finer increments (e.g., 11/15, 13/15, 29/36, 31/36). This segmentation provides the required granularity in the intermediate Es/N0 range while organizing complexity into a structured, manageable framework that maintains DVB-S2 compatibility
4Reliability
If new modulation schemes like 256-APSK with multiple rings are used, then operational capability at extreme Es/N0 ratios is improved, but system complexity increases
Solution Approach 1:
The patent designs a universal encoding and modulation framework that handles multiple APSK constellations and code rates through a single standardized interface. The LDPC encoder and modulation system are designed to work with any of the supported constellations (16-APSK, 32-APSK, 64-APSK, 256-APSK) and code rates, reducing implementation complexity while maintaining extended operational capability across −10 dB to 24 dB and beyond
Data Source
AI summary
Modulation and coding schemes are provided for improved performance of wireless communications systems to support services and applications for terminals with operational requirements at relatively low Es/N0 ratios and terminals at relatively high Es/N0 ratios. The new modulation and coding schemes provide new BCH codes, low density parity check (LDPC) codes and interleaving methods. The modulation and coding schemes also provide new modulation signal constellations.