Preamble Sequence Allocation for High Mobility Cells
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Solution Overview
Problem
The existing sequence allocation systems for E-UTRAN random access procedures face challenges in balancing cubic metric (CM) and maximum supportable cell size criteria, leading to conflicting sequence ordering that affects channel interference and cell coverage, particularly in high and low mobility cells.
Innovation Solution
A flexible sequence allocation method that divides sequences into groups based on CM, segments them according to supported cell sizes, and orders them cyclically, allowing for efficient allocation across mobility boundaries, thereby optimizing sequence reuse and minimizing errors in UE sequence selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If root sequences are ordered according to cubic metric (CM), then power back-off is optimized and adjacent channel interference is minimized, but cell coverage varies depending on the root sequence and sequence reuse is reduced
Solution Approach 1:
The patent segments the 838 root sequences into multiple groups based on their cubic metric values. Each group contains sequences with similar CM characteristics, allowing the system to select appropriate groups for different cell sizes and mobility conditions. This segmentation enables simultaneous optimization for low interference (by selecting low CM sequences) and adequate coverage (by selecting appropriate groups based on cell parameters).
Solution Approach 2:
The patent applies different sequence allocation strategies to different local conditions. For each cell, the system locally selects root sequence groups based on the specific cell's size and mobility characteristics. This allows each cell to use sequences with optimal CM properties for its specific conditions, rather than applying a uniform ordering across all cells.
2Adaptability or versatility
If root sequences are ordered according to maximum supportable cell size, then sequence reuse is optimized for high mobility cells, but cubic metric variation increases and power back-off requirements vary
Solution Approach 1:
The patent segments root sequences into groups based on CM thresholds, where each group can support a specific range of cell sizes. The system then selects appropriate groups based on the actual cell configuration, enabling optimization for both cell size coverage and CM properties simultaneously.
Solution Approach 2:
The patent introduces dynamic selection of root sequence groups based on cell parameters. The network can adaptively choose which sequence groups to allocate to different cells based on real-time conditions such as cell size, mobility requirements, and interference levels, rather than using a fixed ordering.
3Productivity
If a single root sequence is allocated to multiple cells, then sequence reuse increases and resource utilization improves, but sequence restriction schemes must be applied and mobility management becomes complex
Solution Approach 1:
The patent segments the root sequences into multiple groups that can be independently allocated to different cells. This allows a cell to use sequences from multiple groups, increasing the effective number of available preambles and enabling better sequence reuse across the network while maintaining flexibility for mobility management.
Solution Approach 2:
The patent makes root sequences universal across multiple cells by allowing the same sequence groups to be allocated to different cells with different parameters. The sequences serve multiple functions across the network, improving resource utilization while the group-based structure maintains manageability through systematic allocation rules.
Data Source
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AI summary
A set of specific sequences comprising a set of root sequences and cyclic shifts thereof is searched, wherein it is started from a root sequence index indicating a root sequence of ordered root sequences, available cyclic shifts of the root sequence are included, and it is continued with a next root sequence if necessary for filling the set, wherein the ordered root sequences are obtained by ordering sequences of a predetermined length and number in accordance with cubic metric of each of the sequences and a size of a high mobility cell each of the sequences supports.