CAZAC Pilot Sequence Allocation for Interference Reduction
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Solution Overview
Problem
In wireless communication systems using CAZAC sequences as pilot signals, the inability to apply scrambling codes limits the effectiveness of interference reduction by combining pilot blocks, as the unique characteristics of CAZAC sequences are lost when multiplied by random sequences, resulting in unchanged interference patterns across multiple pilot blocks.
Innovation Solution
A method for allocating different pilot sequences to each pilot block within a frame for each cell, ensuring that pilot sequences used in one cell are distinct from those used in adjacent cells, allowing for the reuse of pilot sequences while maintaining their CAZAC properties, thereby enabling effective interference reduction by combining pilot blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If scrambling codes are applied to CAZAC sequences to reduce interference, then interference reduction capability is improved, but the unique characteristics of CAZAC sequences are lost resulting in unchanged interference patterns
Solution Approach 1:
The patent changes the parameter of pilot sequence allocation by assigning different CAZAC sequences (with different root indices) to different cells and different pilot blocks, rather than applying scrambling codes. This maintains the CAZAC characteristics while achieving interference reduction through parameter variation.
Solution Approach 2:
The patent segments the pilot sequence allocation by dividing different cells and different pilot blocks within cells to use different CAZAC sequences. This segmentation approach allows interference reduction across multiple dimensions (cell-level and block-level) while preserving CAZAC properties.
2Productivity
If the same pilot sequence is reused across multiple pilot blocks, then resource efficiency is improved, but interference reduction by combining pilot blocks becomes ineffective
Solution Approach 1:
The patent applies segmentation by dividing pilot sequence allocation into two levels: cell-level segmentation (different cells use different sequences) and block-level segmentation (different pilot blocks within a cell use different sequences). This enables interference reduction while maintaining reasonable resource utilization.
Solution Approach 2:
The patent implements local quality by allowing different pilot blocks within the same cell to have different CAZAC sequence characteristics. This localized differentiation enables interference reduction specifically where needed (across blocks) while maintaining resource efficiency within each block.
Data Source
AI summary
A device and method in which a plurality of Zadoff-Chu sequences is allocated to a frame, a value of a parameter in the Zadoff-Chu sequence is different among the plurality of Zadoff-Chu sequences, and the Zadoff-Chu sequence allocated to the frame is different among a plurality of cells.