2-Step RACH Message A DMRS Configuration
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Solution Overview
Problem
Current wireless communication systems face inefficiencies in signal transmission and reception, particularly in configuring and mapping preambles to physical uplink shared channels (PUSCH) occasions, which affects the utilization of demodulation reference signals (DMRS) resources.
Innovation Solution
A method and apparatus for a 2-step random access channel (RACH) procedure and PUSCH demodulation reference signal (DMRS) configuration in wireless communication systems, where the number of DMRS ports is determined in {1, 2, 4} and pseudo-random sequence generation is initialized based on higher-layer parameters, with scrambling IDs derived from PRACH preambles, enabling efficient transmission and reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional 4-step RACH procedure is used, then compatibility with existing systems is maintained, but access latency and signaling overhead increase
Solution Approach 1:
The patent combines the traditional 4-step RACH procedure into a 2-step procedure by merging Message 1 and Message 3 into a single Message A (containing PRACH preamble and PUSCH), and merging Message 2 and Message 4 into Message B. This reduces the number of round-trip exchanges and lowers access latency while maintaining system compatibility through backward-compatible configuration options.
Solution Approach 2:
The patent enables the UE to transmit both the random access preamble and uplink data in Message A simultaneously, performing the data transmission action in advance rather than waiting for the traditional multi-step acknowledgment and scheduling process. This preliminary action reduces the overall access time.
2Reliability
If DMRS resources are increased for better signal demodulation, then reception reliability improves, but resource utilization efficiency decreases
Solution Approach 1:
The patent applies different DMRS port configurations and CDM group assignments to different PUSCH occasions and preamble groups, optimizing the reference signal resources locally for each transmission scenario rather than using a uniform high-overhead configuration across all cases. This achieves reliable demodulation with efficient resource usage.
Solution Approach 2:
The patent dynamically adjusts DMRS parameters such as the number of ports, CDM group assignments, and scrambling IDs based on the specific PUSCH configuration and preamble group, optimizing the balance between demodulation reliability and resource efficiency for each transmission instance.
3Productivity
If more PUSCH occasions are allocated for preamble mapping, then access capacity increases, but DMRS resource overhead increases
Solution Approach 1:
The patent divides PUSCH occasions into different groups and associates each group with specific preamble ranges and DMRS configurations. This segmentation allows multiple PUSCH occasions to share DMRS resources through code division multiplexing, increasing access capacity while controlling resource overhead.
Solution Approach 2:
The patent designs the DMRS resource configuration to serve multiple PUSCH occasions simultaneously through CDM group sharing and scrambling ID derivation from preamble indices. A single DMRS configuration can support multiple access attempts, providing multi-functionality that increases capacity without proportionally increasing overhead.
Data Source
AI summary
The present disclosure relates to a method carried out by a terminal in a wireless communication system, and a device supporting same, and more specifically relates to a method comprising a step of obtaining a message A comprising a physical uplink shared channel (PUSCH) and a physical random access channel (PRACH) preamble, and a step of transmitting the message A, wherein the PUSCH is transmitted on the basis of information related to a PUSCH configuration for the message A that is being received, and, on the basis of the information relating to the PUSCH configuration comprising information relating to the instruction of a code division multiplexing (CDM) group for a demodulation reference signal (DM-RS) for the PUSCH, the CDM group is set to be a group indicated by information relating to the indication of the CDM group among two pre-set groups. The present disclosure also relates to a device supporting same.