Downlink Dedicated Pilot Frequency Hopping for Inter-Cell Interference
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Solution Overview
Problem
In LTE systems, the downlink dedicated pilot signal interference between adjacent cells is significant due to fixed frequency domain positions, leading to increased peak power for users at cell edges and interference between UEs in different cells.
Innovation Solution
A method and base station implementation for frequency hopping of the downlink dedicated pilot signal, where a frequency hopping offset is determined based on the cell identity, allowing the pilot signal's frequency domain position to be recalculated and mapped across the entire frequency domain, ensuring distinct positions for adjacent cells and preventing collisions with common pilot signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the downlink dedicated pilot signal uses a fixed frequency domain position, then the signal structure is simple and easy to implement, but the interference between UEs in different cells increases and peak power is generated for users at cell edges
Solution Approach 1:
The patent applies frequency hopping to make the frequency domain position of the downlink dedicated pilot signal dynamic rather than fixed. The frequency position changes according to a hopping pattern determined by cell identity and resource block allocation, which reduces persistent interference between adjacent cells while maintaining structured signal design.
Solution Approach 2:
The patent changes the frequency domain parameter of the pilot signal by introducing frequency hopping offsets based on cell identity. This parameter change allows different cells to use different frequency positions for their pilot signals, thereby reducing inter-cell interference while keeping the signal structure manageable through standardized hopping rules.
2Ease of operation
If the frequency domain position of the downlink dedicated pilot signal is fixed, then resource mapping is straightforward, but peak power is generated for users at cell edges
Solution Approach 1:
The patent introduces dynamic frequency hopping to change the frequency domain position of pilot signals across different resource blocks. This dynamic approach distributes the signal energy across multiple frequency positions, reducing peak power concentration at any single frequency for users at cell edges while maintaining systematic resource mapping through standardized hopping patterns.
3Productivity
If adjacent cells use the same downlink dedicated pilot frequency, then frequency allocation is efficient and simple, but interference between adjacent cells increases
Solution Approach 1:
The patent applies local quality by making the frequency domain position of pilot signals cell-specific through frequency hopping offsets derived from cell identity. Each cell locally adapts its pilot signal frequency positions based on its identity, ensuring that adjacent cells use different frequency positions and thereby reducing interference while maintaining overall frequency allocation efficiency.
Data Source
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AI summary
A method for frequency hopping of a downlink dedicated pilot frequency, comprises: for the downlink dedicated pilot frequency, determining a frequency hopping offset corresponding to the downlink dedicated pilot frequency according to a cell identity of a cell to which it pertains (S202); determining a frequency domain position of the downlink dedicated pilot frequency in a physical resource block to which it belongs after a frequency hopping according to the frequency hopping offset and a relative frequency domain position of the downlink dedicated pilot frequency (S204); performing resource mapping for the downlink dedicated pilot frequency on the entire frequency domain according to the determined frequency domain position (S206). A base station is used to implement the frequency hopping of the downlink dedicated pilot frequency.