Filterbank Multicarrier Transmitter Frequency-Domain Synchronization
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Solution Overview
Problem
Time-domain based synchronization schemes for filterbank-based multicarrier communication systems face challenges such as failure in high interference scenarios, high implementation costs, distortion, and reduced spectral efficiency, especially in dynamic or shared spectrum access contexts where interference from other users is prevalent.
Innovation Solution
An efficient frequency-domain based synchronization scheme is implemented by assigning pilot values and payload values in a processor-configured multicarrier signal, allowing for improved synchronization and interference mitigation through optimized pilot symbol arrangement and auxiliary pilot values, enabling robust synchronization even in fragmented frequency spectra.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If time-domain based synchronization schemes are used, then synchronization can be performed in conventional systems, but the scheme fails in high interference scenarios and has high implementation costs
Solution Approach 1:
The patent replaces time-domain synchronization mechanisms with frequency-domain synchronization mechanisms. Specifically, it uses frequency offset estimation based on pilot symbol correlation in the frequency domain, which substitutes the time-domain correlation approach and provides better performance in high interference scenarios while reducing implementation complexity through efficient frequency-domain processing
Solution Approach 2:
The patent changes the domain parameter from time-domain to frequency-domain for synchronization operations. It transforms the synchronization approach by applying inverse fast Fourier transform (IFFT) to convert frequency-domain pilot symbols to time-domain for correlation, then transforms back to frequency-domain for offset estimation, optimizing the parameter domain for each processing stage
2Manufacturing precision
If additional pre-filtering techniques are applied in time-domain, then signal distortion can be reduced, but implementation costs increase significantly
Solution Approach 1:
The patent substitutes time-domain pre-filtering operations with frequency-domain processing operations. Instead of applying complex time-domain filters before synchronization, it uses frequency-domain pilot symbols and correlation-based estimation, achieving similar or better signal quality with reduced implementation complexity through the use of IFFT and FFT operations
3Measurement precision
If a large number of pilot symbols are used for synchronization, then synchronization accuracy improves, but spectral efficiency decreases
Solution Approach 1:
The patent applies partial action by using a reduced set of pilot symbols strategically positioned in the frequency domain rather than excessive pilot symbols throughout the signal. The frequency-domain approach allows accurate offset estimation with fewer pilots by exploiting the structure of the multicarrier signal and the properties of the pilot symbol arrangement
Solution Approach 2:
The patent makes the pilot symbols multi-functional by using them for both data transmission and synchronization purposes. The same pilot symbols embedded in the frequency-domain signal structure serve dual roles: carrying information and enabling frequency offset estimation through correlation, thereby improving spectral efficiency while maintaining synchronization accuracy
4Ease of operation
If time-domain synchronization schemes are implemented, then conventional processing can be used, but implementation costs scale linearly with the number of users
Solution Approach 1:
The patent substitutes time-domain correlation-based synchronization with frequency-domain correlation-based synchronization. The frequency-domain approach uses IFFT to convert pilot symbols to time-domain for correlation, then FFT to return to frequency-domain for offset estimation, providing a scalable solution that does not linearly increase complexity with the number of users
Solution Approach 2:
The patent employs periodic pilot symbol arrangement in the frequency domain, where pilots are placed at regular intervals across subcarriers. This periodic structure enables efficient correlation-based synchronization that can handle multiple users simultaneously without linearly increasing processing complexity, as the same correlation operation can be applied to detect periodic patterns from multiple users
Data Source
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AI summary
The invention relates to a filterbank-based multicarrier transmitter (100) for transmitting a multicarrier signal, the multicarrier signal comprising a synchronization part and a payload part, the synchronization part comprising K1 frequency sub-channels, the payload part comprising K2 frequency sub-channels, the K1 frequency sub-channels of the synchronization part being arranged to form M subsequent multicarrier symbols, the filterbank-based multicarrier transmitter (100) comprising a processor (101) being configured to assign subsequent pilot values of a pilot sequence to every Pth frequency sub-channel of the K1 frequency sub-channels of the synchronization part to obtain a pilot symbol of the multicarrier signal, and to assign subsequent payload values of a payload sequence to subsequent frequency sub-channels of the K2 frequency sub-channels of the payload part to obtain a payload symbol of the multicarrier signal, wherein P is greaterthan 1, and wherein the processor (101) is configured to assign subsequent groups of subsequent pilot values to every Qth symbol of the M multicarrier symbols, wherein Q is equal to or greater than 1.