Doppler Shift Compensation Using Bandwidth Difference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing Doppler shift compensation methods that rely on known signal sequences, such as preambles and postambles, reduce transmission efficiency and are ineffective in compensating for Doppler shifts in satellite IoT communication systems.
Innovation Solution
A Doppler shift compensation device and method that utilizes a signal acquisition unit, bandwidth specifying unit, and compensation unit to determine and compensate for Doppler shifts based on the difference between reception and transmission bandwidths, regardless of the presence of known signal sequences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a known signal sequence such as a preamble and a postamble is added to a frame for Doppler shift compensation, then Doppler shift can be obtained from the preamble and postamble, but the ratio of payload in the frame decreases, leading to a decrease in transmission efficiency
Solution Approach 1:
The invention extracts Doppler shift information directly from the payload data itself rather than from separate known signal sequences. By utilizing the payload as the source of Doppler shift measurement, the system eliminates the need for preambles and postambles, thereby maintaining full payload ratio and transmission efficiency while still achieving accurate Doppler shift compensation
Solution Approach 2:
The payload serves multiple functions: it carries the actual data information and simultaneously provides the reference signal for Doppler shift measurement. This multi-functionality eliminates the need for dedicated reference signals (preamble/postamble) and maximizes the utilization of transmitted data for both communication and synchronization purposes
2Reliability
If a known signal sequence is added to compensate for Doppler shift, then Doppler shift compensation can be achieved, but the frame structure becomes more complex and overhead increases
Solution Approach 1:
The invention removes the separate known signal sequence components (preamble and postamble) from the frame structure. Instead, it extracts Doppler shift information directly from the payload data, thereby simplifying the frame structure and reducing overhead while maintaining the reliability of Doppler shift compensation
Solution Approach 2:
Conventionally, known signals are added to enable Doppler shift measurement. The invention inverts this approach by using the payload itself as the reference signal for Doppler shift measurement, thereby eliminating the need for additional known signals and simplifying the overall system structure
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
Enables effective Doppler shift compensation in satellite IoT communication systems, maintaining transmission efficiency by compensating for Doppler shifts without relying on known signal sequences.
Implementation Method 1
a shift specifying unit that specifies a change amount of a Doppler shift per time on the basis of a difference between a bandwidth of a transmission signal in the transmission device and the reception bandwidth
Data Source
AI summary
A signal acquisition unit acquires a reception signal received by a reception device from a transmission device that moves relative to the reception device. A bandwidth specifying unit specifies a reception bandwidth that is a bandwidth of the reception signal. A shift specifying unit specifies a change amount of a Doppler shift per time on the basis of a difference between a bandwidth of a transmission signal in the transmission device and the reception bandwidth. A compensation unit compensates for a change of the Doppler shift of the reception signal on the basis of the change amount specified.