Pilot Sequence Design for Wireless Interference Management
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Solution Overview
Problem
In wireless communications systems, existing methods for pilot sequence design in multi-cell/sector cooperation (CoMP) face challenges in managing interference and optimizing pilot sequence length, leading to increased overhead and reduced efficiency due to the need for orthogonal sequences among all cells, which is impractical with current techniques.
Innovation Solution
A method and controller that group cells based on their significance as interferers, designing pilot sequences to be orthogonal between significant interferers while allowing non-orthogonal sequences for insignificant interferers, reducing the overall length and overhead of pilot sequences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pilot sequences are made orthogonal among all cells to manage interference, then interference management is improved, but pilot sequence length and communications overhead increase rapidly
Solution Approach 1:
The patent segments cells into different groups (first group, second group, third group) based on their interference characteristics. Pilot sequences are made orthogonal only within each group, rather than requiring orthogonality across all cells. This segmentation allows the system to maintain interference management where needed while reducing overall pilot sequence length and overhead.
2Object-affected harmful factors
If pilot sequences are made orthogonal among all cells, then interference between cells is reduced, but communications overhead increases rapidly
Solution Approach 1:
The patent applies local quality by making pilot sequences orthogonal only for cells that are significant interferers to each other (first group and second group), while allowing non-orthogonal sequences for cells with minimal interference (third group). This localized orthogonality approach reduces communications overhead while maintaining interference management where it is most needed.
3Productivity
If pilot sequences are shortened to reduce overhead, then communications efficiency is improved, but interference management capability deteriorates
Solution Approach 1:
The patent segments the cell population into groups with different interference characteristics. By requiring orthogonality only within specific groups (first and second groups) rather than across all cells, the system can use shorter pilot sequences while maintaining adequate interference management capability for the most critical interferers.
Solution Approach 2:
The patent changes the orthogonality parameter selectively - maintaining orthogonality for significant interferers (first and second groups) while relaxing it for less critical cells (third group). This parameter change allows shorter pilot sequences while preserving interference management where it matters most.
Data Source
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AI summary
A method for pilot sequence design in a communications system includes selecting an initial cell in the communications system, and grouping other cells in the communications system relative to the initial cell into one of a neighbor group and a non-neighbor group in accordance with a neighborness measure of each of the other cells to the initial cell. The method also includes designing pilot sequences that are substantially orthogonal to one another for the initial cell and the other cells in the neighbor group, and providing information about the pilot sequences to the initial cell and the other cells in the communications system.