Direct Current Subcarrier Indication for Satellite Doppler Offset
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In satellite communication, the high relative speed between a satellite and a terminal device generates a large Doppler frequency offset, leading to issues with direct current subcarrier alignment between the transmit and receive ends, causing signal processing challenges due to direct current leakage affecting the bandwidth at both locations.
Innovation Solution
A method is introduced to indicate the location of direct current subcarriers on both the transmit and receive ends by extending the index value range and using additional indication information, such as a Boolean variable, to accurately determine the subcarrier positions within or outside the carrier frequency band, enabling proper signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Doppler frequency offset compensation is performed, then decoding performance is improved, but direct current subcarrier alignment between transmit and receive ends deteriorates, causing direct current leakage to affect bandwidth at both locations
Solution Approach 1:
The patent segments the subcarrier indication into two separate parts: transmit end DC subcarrier indication and receive end DC subcarrier indication. This allows the system to independently indicate and handle DC subcarrier locations at both ends, resolving the alignment issue caused by Doppler compensation while maintaining decoding performance.
Solution Approach 2:
The patent introduces an intermediary mechanism through extended index value ranges and additional indication information (such as Boolean variables) that mediate between the transmit and receive ends. This intermediary allows both ends to accurately determine their respective DC subcarrier locations despite Doppler frequency offset, preventing direct current leakage issues.
2Measurement precision
If the index value range is extended to indicate subcarrier positions outside the carrier frequency band, then subcarrier location indication accuracy is improved, but information processing complexity increases
Solution Approach 1:
The patent applies local quality by using different indication methods for different scenarios: extended index values are used when subcarriers are outside the carrier frequency band, while conventional indexing is sufficient for in-band subcarriers. This localized approach improves accuracy where needed without unnecessarily increasing complexity everywhere.
Solution Approach 2:
The patent changes the parameter range of index values to accommodate subcarrier positions outside the traditional carrier frequency band. By extending the index value range and introducing additional indication parameters (such as Boolean flags), the system can accurately indicate subcarrier locations while managing processing complexity through structured parameter expansion.
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 solution ensures that the receive end can accurately learn and process the direct current subcarrier locations, improving signal decoding performance and system reliability by aligning subcarriers within the carrier frequency band, even under high Doppler frequency offsets.
Implementation Method 1
Because a relative speed between a satellite and a terminal device is high, a large Doppler frequency offset is generated between the satellite and the terminal device
Data Source
AI summary
The present disclosure relates to methods for indicating a direct current subcarrier and communication apparatuses. In one example method, a second communication apparatus may explicitly or implicitly indicate a location of a first direct current subcarrier and a location of a second direct current subcarrier to a first communication apparatus. The first direct current subcarrier is a direct current subcarrier corresponding to a transmit frequency used by the second communication apparatus. The second direct current subcarrier is a direct current subcarrier corresponding to a receive frequency used by the first communication apparatus.