Hierarchical Modulation for Variable SDAR Data Performance
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Solution Overview
Problem
Current satellite digital audio radio (SDAR) systems lack the ability to differentiate between high and low priority data services, resulting in uniform performance levels that do not adequately protect primary data streams, such as streaming audio, and do not efficiently utilize available bandwidth and signal-to-noise ratio.
Innovation Solution
The implementation of hierarchical modulation, where high priority data is embedded within or superimposed upon low priority data, with varying error protection levels and energy per symbol, allowing for differentiated performance levels within data packets, and the use of message headers to instruct demodulation and error correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If uniform performance levels are applied to all user data in SDAR systems, then system simplicity is maintained, but high priority data services do not receive adequate protection and bandwidth utilization is inefficient
Solution Approach 1:
The patent segments user data into different priority levels (first priority and second priority data) and applies different error protection mechanisms to each segment. High priority data receives stronger forward error correction while low priority data receives reduced protection, resolving the contradiction between reliability and complexity by treating different data segments differently rather than applying uniform protection.
Solution Approach 2:
The patent implements local quality by varying the error protection level according to the specific data segment's priority requirements. Instead of uniform system-wide protection, each data segment receives protection quality localized to its needs, allowing high priority data to have enhanced reliability while maintaining system overall simplicity through standardized processing procedures.
2Reliability
If high-power transmitters are used to overcome weather conditions and interference in radio wave transmission, then signal reliability is improved, but energy consumption increases and cost-effectiveness decreases
Solution Approach 1:
The patent changes the parameter of error protection level based on data priority rather than using fixed high-power transmission for all data. By dynamically adjusting forward error correction strength according to data importance, the system achieves reliable transmission of critical data while reducing energy consumption on less critical transmissions, avoiding the need for consistently high-power operation.
Solution Approach 2:
The patent applies partial action by providing excessive error protection only where necessary (high priority data) rather than uniformly across all transmissions. Low priority data receives minimal protection, avoiding the excessive energy consumption that would result from applying maximum protection or power to all data segments equally.
3Reliability
If digital modulation techniques are used to compensate for communication link shortfalls, then transmission quality is improved, but system complexity and demodulation requirements increase
Solution Approach 1:
The patent segments the data stream into priority-based channels with different modulation and error correction characteristics. This segmentation allows the system to use complex digital modulation techniques selectively on high priority data where quality is critical, while using simpler techniques on low priority data, thereby improving overall transmission quality without requiring all system components to handle maximum complexity.
4Productivity
If the same error protection level is applied to all data services, then system operation is simplified, but throughput optimization for different service types is prevented
Solution Approach 1:
The patent implements local quality by tailoring error protection levels to the specific requirements of different data services. Streaming audio data receives appropriate protection levels optimized for its continuous flow requirements, while other data types receive protection matched to their characteristics. This localized optimization improves overall throughput by ensuring each service type operates at its optimal performance point rather than being constrained by uniform protection levels.
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 optimizes data throughput by providing enhanced protection and performance for high priority data while efficiently utilizing bandwidth and signal quality, ensuring reliable transmission of both primary and secondary data services.
Implementation Method 1
A modulator combines a message header and two inputs using phase shift keying into data structured and arranged as a data packet
Data Source
AI summary
The present invention generally relates to the transmission of digital data, and more particularly, to the transmission of digital data in a satellite digital audio radio (“SDAR”) system. In the SDAR system, there may be different types of required services. Some of these services may be considered high priority and others may be of a lower priority. Current SDAR systems have the same performance on all user data. Therefore, there is a need to vary the performance of different services.The present invention provides a method and apparatus for optimizing the throughput (i.e. information) in a digital transmission system by transmitting the different services with different performance levels. The present invention addresses the need in the art to vary the performance of different services (i.e., levels of data). Because the performance of the primary level of data will not be equal to the performance of the secondary level of data, the primary level will need to be further protected. The primary level data may be streaming data. The secondary level data does not need as much protection because it may be rebroadcast repeatedly. The easiest and most cost effective solution is to integrate multiple symbols for a secondary level bit. The present invention provides a method and apparatus in which the power level for the data levels can be set within each data packet using a message header providing the different services with different levels of performance.