Sub-band Waveform Generation for Wideband Spectral Localization
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Solution Overview
Problem
Current communication systems face challenges in efficiently generating waveforms that effectively utilize subcarriers, particularly in supporting wider channel bandwidths and improving spectral localization.
Innovation Solution
The proposed solution involves mapping frequency-domain symbols onto subcarriers into multiple sets, performing symbol-wise rotation, converting to the time domain, inserting a cyclic prefix, and then performing sub-band filtering, interpolation, and combination to generate a single waveform.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If larger transform sizes are used to support wider channel bandwidths, then channel bandwidth capability is improved, but device complexity and processing requirements increase
Solution Approach 1:
The frequency-domain symbols are divided into multiple sets, where each set is processed separately through IFFT to generate sub-band waveforms. These sub-band waveforms are then combined to form the final waveform. This segmentation allows the system to support wider channel bandwidths by processing smaller transform sizes in parallel, avoiding the need for a single large transform that would increase device complexity.
2Manufacturing precision
If traditional waveform generation methods are used, then implementation simplicity is maintained, but spectral localization is insufficient
Solution Approach 1:
The waveform generation is segmented into multiple sub-band processing stages, where each sub-band waveform is generated separately with proper spectral shaping. This segmentation enables improved spectral localization by allowing independent optimization of each sub-band's spectral characteristics before combination, achieving better overall spectral containment than traditional single-stage methods.
Solution Approach 2:
Cyclic prefixes are inserted into each time-domain symbol before the sub-band waveforms are combined. This preliminary action ensures that each sub-band waveform has proper temporal structure and spectral properties established before combination, which improves spectral localization and reduces inter-block interference in the final composite waveform.
3Manufacturing precision
If multiple sub-band waveforms are generated and combined, then spectral containment is improved, but processing time increases
Solution Approach 1:
The processing is segmented into parallel sub-band operations that can be executed simultaneously. By dividing the frequency-domain symbols into multiple sets and processing each set through separate IFFT operations, the system achieves improved spectral containment through multiple sub-band waveforms while reducing overall processing time through parallel execution, rather than sequential processing of a single large transform.
Data Source
AI summary
There is provided an apparatus comprising means for: mapping frequency-domain symbols on a plurality of subcarriers into at least two sets, each set comprising symbols of at least one of the plurality of subcarriers; for each set: performing symbol-wise rotation based on a complex coefficient value and converting the rotated symbols from the frequency domain to the time domain; or converting the symbols from the frequency domain to the time domain and performing symbol-wise rotation on the time-domain symbols based on the complex coefficient value; inserting a cyclic prefix into each time-domain symbol; concatenating the time-domain symbols resulting from the cyclic prefix insertion to create a sub-band waveform; and performing sub-band filtering, interpolation and combination based on the sub-band waveform for each of the sets to generate a single waveform.