Threshold-Based Two-Step RACH Access for Lower Latency
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently performing random access channel (RACH) procedures, particularly in 5G networks, due to varying channel conditions and the need for enhanced reliability and low latency in diverse communication scenarios.
Innovation Solution
A method and device for performing a 2-step RACH procedure in a wireless communication system, involving threshold-based transmission of messages A and B, utilizing Reference Signal Received Power (RSRP) measurements for synchronization signal blocks (SSB) and Channel State Information-Reference Signals (CSI-RS) to ensure optimal beam selection and contention resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional multi-step RACH procedure is used, then reliability is improved through multiple message exchanges, but latency increases due to the sequential transmission of multiple messages
Solution Approach 1:
The patent combines Message 3 and Message 4 into a single Message A that is transmitted simultaneously with the random access preamble. This merging of multiple sequential messages into one combined message reduces the number of transmission steps, thereby decreasing latency while maintaining the reliability functions through the integrated content of Message A which includes both scheduling information and contention resolution identifiers.
2Productivity
If threshold-based transmission is implemented, then channel access efficiency is improved, but device complexity increases due to additional threshold evaluation logic
Solution Approach 1:
The patent introduces threshold parameters (first threshold for channel quality, second threshold for RSRP) that dynamically control the transmission behavior. By changing the transmission decision based on these parameter thresholds, the system achieves efficient channel access without requiring complex evaluation logic, as the thresholds provide clear decision boundaries for when to transmit Message A.
3Reliability
If beam selection based on RSRP threshold is performed, then communication reliability is improved, but measurement and selection complexity increases
Solution Approach 1:
The patent applies different threshold criteria to different beam selection scenarios. Instead of a uniform complex evaluation, the system uses specific RSRP thresholds (second threshold for SSB, third threshold for CSI-RS) that are appropriately tuned for each beam type and channel condition, simplifying the measurement and selection process while maintaining high reliability through locally optimized threshold application.
Data Source
AI summary
Disclosed is a method whereby a terminal carries out a random access channel (RACH) procedure in a wireless communication system. In particular, the method may comprise: receiving a first threshold related to channel quality for the transmission of message A including a physical random access channel (PRACH) and a physical uplink shared channel (PUSCH); on the basis that the first threshold is satisfied, transmitting message A; and in response to message A, receiving message B including contention resolution information.