PRACH Preamble Format Segmentation for NTN Random Access
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Solution Overview
Problem
Current random-access procedures in 5G NR systems, especially in Non-Terrestrial Networks (NTN), face challenges with large cell sizes and increased user equipment (UE) density, leading to inefficiencies in preamble format utilization and increased interference due to the one-size-fits-all approach, which limits the number of available preambles and causes timing misalignment issues.
Innovation Solution
Implementing a method that allows for multiple physical random-access (PRACH) preamble formats to be configured and used by UEs based on their specific characteristics and capabilities, such as timing advance pre-compensation, to optimize random-access procedures and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a one-size-fits-all PRACH preamble format is used in large NTN cells, then the system configuration is simple, but the number of available preambles is limited and timing misalignment issues occur
Solution Approach 1:
The patent segments the single PRACH configuration into multiple configurations, each with different preamble formats tailored to specific UE groups. This allows the system to provide multiple preamble formats (e.g., different lengths or structures) simultaneously, increasing the total number of available preambles while maintaining manageable configuration through group-based organization.
Solution Approach 2:
The patent introduces dynamic adaptability by allowing UEs to select from multiple PRACH preamble formats based on their capabilities and positioning accuracy. The system transitions from a static, fixed configuration to a dynamic, flexible approach where the appropriate preamble format is chosen based on real-time UE characteristics and cell conditions.
2Ease of operation
If a one-size-fits-all PRACH preamble format is used, then the configuration is uniform, but interference increases due to timing misalignment in large cells
Solution Approach 1:
The patent applies local quality by tailoring specific preamble formats to specific UE groups based on their positioning accuracy and capabilities. UEs with higher positioning accuracy can use preambles optimized for their timing characteristics, while UEs with lower accuracy use different formats, thereby reducing interference from timing misalignment while maintaining overall system coherence.
Solution Approach 2:
The patent changes key parameters of the PRACH preamble format (such as length, structure, or timing characteristics) based on UE group characteristics. By adjusting these parameters dynamically for different UE groups, the system optimizes timing alignment and reduces interference without requiring complete system reconfiguration.
3Productivity
If multiple PRACH preamble formats are configured for different UE groups, then preamble utilization efficiency improves, but the configuration complexity increases
Solution Approach 1:
The patent manages configuration complexity by segmenting UEs into distinct groups based on their positioning accuracy and capabilities. Each group is assigned specific preamble formats, which simplifies the configuration process compared to customizing for each individual UE while still achieving high preamble utilization efficiency across the diverse UE population.
Solution Approach 2:
The patent creates multi-functionality by designing preamble formats that can serve multiple purposes within their designated UE groups. The same preamble format can be used by multiple UEs with similar characteristics, and the configuration framework can accommodate various UE types and scenarios, thereby reducing overall configuration complexity while maintaining high efficiency.
4Reliability
If multiple PRACH preamble formats are used for different UE groups, then random-access procedure reliability improves, but the system complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring and pre-selecting appropriate preamble formats for different UE groups before the random-access procedure begins. UEs with known positioning accuracy and capabilities can be assigned optimal preamble formats in advance, ensuring reliable timing alignment and reducing the complexity of real-time decision-making during the actual access procedure.
Data Source
AI summary
A method performed by apparatus for providing access to a communication network is disclosed. The method includes transmitting to at least one user equipment (UE) system information including random-access configuration information for configuring the UE to perform random-access procedures. The random-access configuration information includes a plurality of different physical random-access channel (PRACH) preamble formats that can be applied by the UE in a random-access procedure. The apparatus receives, from the UE, signalling for initiating a random-access procedure, the signalling including a random-access preamble having a one of the plurality of different PRACH preamble formats and communicates with the UE to continue and complete the random-access procedure initiated by the UE.