PRACH Preamble RNTI Determination Using Reference Symbol Index
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Solution Overview
Problem
Current wireless communication systems face challenges in enhancing uplink coverage and configuration flexibility for PRACH (Physical Random Access Channel) in cellular networks, leading to ambiguous RAR (Random Access Response) configurations and inefficient resource utilization.
Innovation Solution
A method involving the transmission of a preamble in a PRACH occasion, where the RNTI (Radio Network Temporary Identification) is determined using a reference time-domain symbol and slot index, allowing for improved timing and resource management, enabling consistent RAR time window initiation and flexible configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coverage enhancement technology is adopted for PRACH, then uplink coverage performance is improved, but RAR configuration becomes ambiguous
Solution Approach 1:
The terminal determines the RAR time window start time and first RNTI by itself using the reference time-domain symbol index and reference slot index, without requiring explicit network configuration. This self-determination mechanism eliminates configuration ambiguity while maintaining coverage enhancement
Solution Approach 2:
The network provides downlink information (reference time-domain symbol index and reference slot index) that enables the terminal to feedback-correctly determine RAR configuration parameters, ensuring both coverage enhancement and unambiguous configuration interpretation
2Device complexity
If RAR time window start time is determined by first time-domain symbol of first PRACH occasion, then configuration is simplified, but flexibility is reduced
Solution Approach 1:
The system dynamically selects the reference time-domain symbol based on whether coverage enhancement is configured. When coverage enhancement is enabled, a reference symbol different from the first time-domain symbol is used, providing adaptive flexibility while maintaining clear configuration
Solution Approach 2:
The RAR time window determination is segmented into different cases: when coverage enhancement is configured versus when it is not. This segmentation allows each case to have its own optimized reference symbol selection, balancing simplicity and flexibility
3Productivity
If first RNTI is determined using reference time-domain symbol and slot index, then RNTI resource utilization is improved, but timing management complexity increases
Solution Approach 1:
The terminal autonomously calculates the first RNTI using the formula involving reference time-domain symbol index and reference slot index, without requiring network provisioning. This self-service approach maximizes RNTI resource utilization while keeping timing management transparent through clear mathematical relationships
Data Source
AI summary
The present application provides a method and device in a node for wireless communications. A first transmitter transmits a first preamble in a first PRACH occasion; a first receiver receives a first signaling, and the first signaling adopts a first RNTI; wherein the first signaling is used to respond to a transmission of the first preamble; a first time-domain symbol is an earliest time-domain symbol of the first PRACH occasion; an index of a reference time-domain symbol and an index of a reference slot are both used to determine the first RNTI, the reference time-domain symbol is a time-domain symbol other than the first time-domain symbol, and the reference time-domain symbol belongs to the reference slot; a time-domain position of the reference time-domain symbol is related to at least one of the first PRACH occasion or the first preamble.