ZC Sequence Sequencing for LTE RACH High-Speed CM Management
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Solution Overview
Problem
Current methods for sequencing ZC sequences in LTE systems face challenges in high-speed scenarios, leading to sequence fragments and inefficient sequence planning due to varying Peak-to-Average Power Ratio (CM) characteristics, which affects the utilization and assignment of ZC sequences.
Innovation Solution
A method that divides ZC sequences into low and high CM groups, further sub-grouping them based on maximum cyclic shift thresholds, and sequencing them according to their CM values to ensure sequences with similar CMs are assigned to the same cell, preventing sequence fragments and improving planning efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ZC sequences are sequenced according to cubic metric (CM) values, then sequence planning can be conveniently performed according to CM characteristics, but sequence fragments are generated under high speed circumstance leading to sequence waste
Solution Approach 1:
The patent segments the ZC sequences into multiple groups based on their maximum cell radius support capabilities under high speed circumstances. By dividing the sequences into distinct groups with different radius support ranges, the system can select appropriate sequences for specific cell sizes, preventing sequence fragment waste while maintaining CM-based planning advantages.
Solution Approach 2:
The patent changes the sequencing parameter from pure CM-based ordering to a hybrid approach that incorporates maximum cell radius support as a primary sorting criterion. This parameter change allows sequences to be organized by their operational suitability for different cell radii, eliminating sequence fragments while preserving CM-based planning flexibility.
2Loss of substance
If ZC sequences are sequenced according to maximum cell radius under high speed circumstance, then sequence fragments are avoided, but CM-based sequence planning cannot be performed
Solution Approach 1:
The patent segments sequences into groups based on maximum cell radius support, then performs CM-based sequencing within each group. This segmentation approach eliminates sequence fragments by ensuring continuous index allocation across groups, while maintaining CM-based planning flexibility within each segment.
Solution Approach 2:
The patent applies different sequencing strategies to different sequence groups: CM-based sequencing is applied locally within each radius-support group, while the overall grouping is based on maximum cell radius capability. This local quality approach preserves CM-based planning advantages while eliminating sequence fragments at the global level.
3Reliability
If cyclic shift limitation rule is applied to settle correlation peak alias in high speed circumstance, then false detection is prevented, but maximum cyclic shift is limited which directly determines maximum cell radius support
Solution Approach 1:
The patent segments ZC sequences into multiple groups, where each group is optimized for specific cell radius ranges under high speed conditions. This segmentation allows the system to select sequences with appropriate cyclic shift characteristics for different cell sizes, maintaining detection accuracy while extending adaptability to various cell radii.
Solution Approach 2:
The patent changes the selection criterion from fixed cyclic shift limitation to dynamic selection based on maximum cell radius support capability. By organizing sequences according to their radius support ranges and selecting appropriate groups based on actual cell size, the system maintains detection accuracy while adapting to different cell radius requirements.
Data Source
AI summary
A method for sequencing the ZC sequences of the RACH is provided, wherein, the method for sequencing the ZC sequences comprises: setting the logical index of each ZC sequence as α, and the physical index of each ZC sequence as u, wherein 1≦u≦N−1,0≦α≦N−2, N is the length of each ZC sequence and N=839; creating the physical indices u corresponding to the logical indices α=0, 1, . . . , 837, sequencing the ZC sequences of the RACH according to the created mapping relationship between the logical indices and the physical indices.