Compact FDSS Filter Representation for Lower PAPR and ISI
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Solution Overview
Problem
The increasing demand for wireless data traffic in 5G/NR communication systems necessitates improved radio interface efficiency and coverage, particularly in higher frequency bands, where beamforming and massive MIMO techniques are employed, but existing technologies face challenges in managing peak-to-average power ratio (PAPR) and inter-symbol interference (ISI) in waveform design.
Innovation Solution
The implementation of compact frequency domain spectral shaping (FDSS) filters through phase rotation, discrete Fourier transform (DFT), spectral extension, and inverse DFT, along with subcarrier mapping and cyclic prefix addition, to optimize waveform design and reduce PAPR while minimizing ISI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional waveform design is used in 5G/NR systems, then basic communication functionality is achieved, but peak-to-average power ratio (PAPR) increases and inter-symbol interference (ISI) occurs
Solution Approach 1:
The patent applies frequency domain spectral shaping by modifying the spectral parameters of the transmitted signal. FDSS filters are designed to shape the frequency spectrum, controlling the roll-off rate and spectral mask characteristics. This parameter change in the frequency domain directly reduces PAPR while minimizing ISI, improving link-level performance without changing the basic OFDM waveform structure
Solution Approach 2:
The patent introduces FDSS filters as an intermediary component between the modulator and the channel. These filters act as a mediator that shapes the spectral characteristics of the signal, providing a compromise between maintaining signal integrity and reducing harmful effects like PAPR and ISI. The filter coefficients serve as an intermediate representation that enables controlled spectral transmission
2Object-affected harmful factors
If spectral shaping filters with high selectivity are used, then adjacent channel interference is reduced, but filter complexity and computational load increase
Solution Approach 1:
The patent segments the spectral shaping function into manageable components by using FDSS filters with specific structural properties. The filter design divides the frequency spectrum into controlled regions with defined roll-off characteristics. This segmentation approach allows achieving adjacent channel interference reduction through modular filter structures rather than requiring complex monolithic filters
Solution Approach 2:
The patent controls filter complexity by carefully selecting and optimizing specific parameters of the FDSS filters, such as the roll-off rate and filter order. By adjusting these parameters, the system achieves the desired spectral selectivity and adjacent channel interference reduction while maintaining computational feasibility. The parameter optimization balances performance requirements with device complexity constraints
Data Source
AI summary
A method of operating an electronic device includes phase rotating an input data vector u of length Ma according to predetermined phase rotation parameters, to generate a phase-rotated data vector, and performing a DFT on the phase-rotated data vector to generate DFT-transformed data. The method also includes applying spectral extension to the transformed data by cyclically extending the DFT-transformed data to produce an extended data vector, performing FDSS by element-wise multiplication of the extended data vector with FDSS coefficients to generate FDSS-processed data, and mapping the FDSS-processed data onto a plurality of subcarriers to generate subcarrier-mapped data. The method also includes performing an IDFT on the subcarrier-mapped data to generate IDFT-transformed data, adding a cyclic prefix to the IDFT-transformed data to generate an output signal, and transmitting the output signal.