Location-Aware Random Access Preambles for Lower Cross-Correlation
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Solution Overview
Problem
In the 6G mMTC scenario, the increased number of terminals and limited preamble sequence resources lead to severe cross-correlation interference and decreased preamble detection performance, affecting access performance.
Innovation Solution
A method for generating random access preamble sequences by selecting target cyclic shift values and root sequences based on terminal location within a cell, using partitioned cell granularity information to allocate candidate sequences, reducing the number of required sequences and minimizing cross-correlation interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of preamble sequence resources is increased to support massive terminals in 6G mMTC scenario, then the access capacity is improved, but the cross-correlation interference accumulates and preamble detection performance deteriorates
Solution Approach 1:
The cell is divided into multiple granularity levels (e.g., full cell, half cell, quarter cell) and terminals are assigned to different granularity segments based on their location. Each segment uses a subset of candidate cyclic shift values, thereby segmenting the preamble sequence resources spatially. This reduces the number of simultaneously active preambles in each segment, lowering cross-correlation interference while maintaining support for massive terminals across the entire cell.
Solution Approach 2:
Different granularity levels are assigned different candidate cyclic shift value ranges and candidate preamble root sequences based on local terminal distribution characteristics. Terminals in different spatial locations use different local configurations optimized for their specific area, reducing overall cross-correlation interference while maintaining adequate preamble resources locally.
2Reliability
If the preamble sequence length is extended to reduce cross-correlation interference, then the preamble detection performance is improved, but the spectrum efficiency is severely impacted
Solution Approach 1:
Instead of changing the physical length of preamble sequences, the invention changes the parameters of cyclic shift values and root sequence selections based on terminal location and granularity level. By optimizing these parameters, the system achieves reduced cross-correlation interference and improved detection performance while maintaining the original preamble sequence length, thus preserving spectrum efficiency.
3Quantity of substance
If the number of ZC root sequences is increased to provide more preamble sequence resources, then the access capacity is improved, but the cross-correlation interference becomes serious and detection performance decreases
Solution Approach 1:
The total pool of ZC root sequences is segmented and allocated to different granularity levels and candidate cyclic shift groups. Terminals in different spatial segments use different root sequence subsets, reducing the number of simultaneously active preambles derived from different root sequences. This segmentation approach reduces the accumulation of cross-correlation interference while maintaining adequate preamble resources for massive terminal access.
Data Source
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AI summary
The present disclosure provides a random access preamble sequence generation method and apparatus, a device, and a storage medium, relating to the field of communication technology. In the present disclosure, the terminal receives candidate cyclic shift values and corresponding candidate preamble root sequences sent by a network device; where the candidate cyclic shift values are determined by the network device based on partitioned cell granularity information, the candidate preamble root sequences are allocated by the network device for the candidate cyclic shift values, and the number of the candidate preamble root sequences is determined based on a synthesis of preamble sequence resources of a cell and the number of the candidate cyclic shift values; the terminal selects a target cyclic shift value and a corresponding target preamble root sequence from the candidate cyclic shift values and the corresponding candidate preamble root sequences based on location information of the terminal itself in the cell; and generates a random access preamble sequence based on the target cyclic shift value and the target preamble root sequence. Due to the reduction in the number of required preamble root sequences in the cell, the cross-correlation interference of the preamble sequences is reduced, and the preamble detection performance and the access performance are improved.