Discrete Spectrum Subcarrier Grouping for Adjacent-Band Isolation
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently utilizing scattered narrow spectra without causing interference with adjacent frequency bands, leading to reduced spectral efficiency and increased design complexity.
Innovation Solution
The technique involves modulating data onto subcarrier groups separated by unused subcarriers, applying specific spreading codes to each group based on their even or odd number of subcarriers, and using inverse Fourier transforms to process these groups, allowing for efficient utilization of discrete spectra without interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data is transmitted using scattered narrow spectra, then spectral efficiency is improved, but interference with adjacent frequency bands occurs
Solution Approach 1:
The patent divides the frequency spectrum into multiple subcarrier groups, where each group is assigned to different users or data streams. This segmentation allows scattered narrow spectra to be utilized efficiently while maintaining isolation between adjacent frequency bands through the use of guard subcarriers, thereby improving spectral efficiency without causing interference.
Solution Approach 2:
The patent introduces guard subcarriers as intermediary elements between active subcarrier groups. These guard subcarriers act as buffers that prevent spectral leakage and interference between adjacent frequency bands, enabling the system to pack more data transmission channels into the available spectrum while maintaining band isolation.
2Object-generated harmful factors
If guard intervals are added to reduce spectral leakage, then interference is reduced, but spectral efficiency deteriorates
Solution Approach 1:
Instead of applying guard intervals to all subcarriers uniformly, the patent applies guard subcarriers selectively only where needed between active subcarrier groups. This partial application reduces spectral leakage at critical interfaces while minimizing the impact on overall spectral efficiency by keeping most subcarriers active.
3Productivity
If scattered spectra are utilized without structured organization, then resource utilization improves, but design complexity increases
Solution Approach 1:
The patent organizes scattered spectra into structured subcarrier groups with clear indexing and assignment rules. Each group is identified by specific subcarrier indices, and the system uses systematic spreading codes for each group. This structured organization enables efficient resource utilization while keeping the design manageable through regular patterns and rules.
Solution Approach 2:
The patent employs systematic parameter changes in the form of spreading codes that are assigned based on subcarrier group indices. By changing the code parameters systematically according to the group assignment, the system can efficiently manage scattered spectra resources without requiring complex individual configurations for each subcarrier group.
Data Source
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AI summary
Methods, apparatus, and systems for efficiently utilizing scattered narrow spectra without introducing interreference among adjacent frequency bands are described. In one example aspect, a wireless communication method includes determining a set of time-domain symbols by applying an inverse Fourier transform to a set of processed data modulated on multiple subcarrier groups. Each subcarrier group comprises an even number of subcarriers and adjacent subcarrier groups are separated by one or more unused subcarriers. The set of processed data is determined by applying a first spreading code to data carried in subcarrier groups having 2×m subcarriers when m is a positive odd number and applying one or more spreading codes to data carried in subcarrier groups having 2×n subcarriers when n is a positive even number. The method also includes transmitting the set of time-domain symbols.