Radio Communication Device Dual-Layer Hopping Pattern Interference Randomization
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Solution Overview
Problem
Current radio communication systems face challenges in randomizing both inter-cell and intra-cell interference, with existing cyclic shift hopping techniques either failing to sufficiently randomize inter-cell interference or leading to orthogonality collapse and increased control signal overhead.
Innovation Solution
A radio communication apparatus and method employing a dual-layer hopping pattern approach, where the first layer varies between cells for inter-cell interference randomization and the second layer varies between radio communication apparatuses on a slot basis for intra-cell interference, maintaining orthogonality between mobile stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If symbol-based first layer hopping pattern is used for inter-cell interference randomization, then inter-cell interference is randomized, but control signal overhead increases
Solution Approach 1:
The hopping pattern is divided into two segments: a first layer hopping pattern that varies between cells for inter-cell interference randomization, and a second layer hopping pattern that varies between radio communication apparatuses for intra-cell interference randomization. This segmentation allows each layer to address specific interference types efficiently without excessive control signaling.
Solution Approach 2:
Different hopping patterns are applied to different layers with different properties: the first layer uses symbol-based hopping for inter-cell interference, while the second layer uses slot-based hopping for intra-cell interference. This local differentiation optimizes interference randomization for each specific interference type while minimizing overall control overhead.
2Object-affected harmful factors
If cyclic shift hopping is performed to randomize interference, then interference randomization is achieved, but orthogonality between mobile stations may collapse
Solution Approach 1:
The system dynamically adjusts cyclic shift values through two-layer hopping patterns. The first layer changes cyclic shifts on a symbol basis for inter-cell interference, while the second layer changes them on a slot basis for intra-cell interference. This dynamic adjustment maintains orthogonality by ensuring that mobile stations using the same time-frequency resources have different cyclic shifts, preventing orthogonality collapse while effectively randomizing interference.
Data Source
AI summary
A radio communication device capable of randomizing both inter-cell interference and intra-cell interference. In this device, a spreading section primarily spreads a response signal in a ZAC sequence set by a control unit. A spreading section secondarily spreads the primarily spread response signal in a block-wise spreading code sequence set by the control unit. The control unit controls the cyclic shift amount of the ZAC sequence used for the primary spreading in the spreading section and the block-wise spreading code sequence used for the secondary spreading in the spreading section according to a set hopping pattern. The hopping pattern set by the control unit is made up of two hierarchies. An LB-based hopping pattern different for each cell is defined in the first hierarchy in order to randomize the inter-cell interference. A hopping pattern different for each mobile station is defined in the second hierarchy to randomize the intra-cell interference.