Two-Step Random Access Channel Configuration for High-Speed Wireless
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Solution Overview
Problem
Conventional two-step random access channel procedures in wireless communications systems face challenges in high-speed scenarios due to the inadequacy of single demodulation reference signal (DMRS) occurrences, leading to unreliable first random access messages.
Innovation Solution
The implementation of additional DMRS occurrences and larger subcarrier spacing for the first random access message in a two-step random access channel procedure, with the base station transmitting configuration parameters to user equipment (UE) based on speed thresholds, allowing the UE to select optimal DMRS configurations for robust message transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If single DMRS occurrence is used in conventional two-step random access channel procedure, then device complexity is reduced, but reliability deteriorates in high-speed scenarios
Solution Approach 1:
The patent implements dynamic DMRS configuration where the base station transmits configuration parameters including multiple DMRS occurrence patterns and subcarrier spacing options. The UE selects appropriate DMRS configurations based on its speed conditions, transitioning from static single DMRS occurrence to dynamic multi-occurrence configurations adapted to high-speed scenarios
Solution Approach 2:
The patent changes key transmission parameters including DMRS occurrence frequency, subcarrier spacing, and DMRS-to-data ratio. By adjusting these parameters based on UE speed conditions, the system achieves reliable message transmission in high-speed scenarios while maintaining compatibility with conventional scenarios
2Reliability
If additional DMRS occurrences and larger subcarrier spacing are implemented, then reliability improves in high-speed scenarios, but device complexity increases
Solution Approach 1:
The base station performs preliminary action by transmitting configuration parameters to the UE before the random access procedure. The configuration includes multiple DMRS occurrence patterns and subcarrier spacing options, enabling the UE to pre-select appropriate parameters based on its speed conditions without real-time negotiation
Solution Approach 2:
The patent segments the DMRS configuration into multiple independent parameters including DMRS occurrence patterns, subcarrier spacing options, and speed threshold levels. This segmentation allows flexible combination and selection of parameters to match different high-speed scenarios without requiring complete reconfiguration
3Loss of time
If conventional random access channel procedure is used, then device complexity is minimized, but connection establishment time increases in high-speed scenarios
Solution Approach 1:
The patent implements parameter changes including larger subcarrier spacing and additional DMRS occurrences that directly reduce transmission time and improve reliability simultaneously. The optimized parameters enable faster message transmission while maintaining robustness against high-speed channel variations
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A wireless device may receive a configuration for a first random access message of a two-step random access channel procedure. The wireless device may select a subcarrier spacing and a number of demodulation reference signal occurrences for transmitting the first random access message based at least in part on the configuration and a speed of the wireless device. The wireless device may transmit the first random access message of the two-step random access channel procedure using the subcarrier spacing and the number of demodulation reference signal occurrences.