MsgA PUSCH Mapping for 2-Step RACH Latency
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently performing a 2-step random access channel (RACH) procedure, particularly in multiplexing physical uplink shared channels (PUSCHs) and mapping demodulation reference signals (DM-RS) in message A (MsgA) to support this procedure.
Innovation Solution
The proposed solution involves a method and apparatus for transmitting and receiving signals in a wireless communication system, specifically by performing a 2-step RACH procedure. This includes obtaining message A containing a physical random access channel (PRACH) preamble and a PUSCH, and transmitting it. The PRACH preamble is mapped to DM-RS ports and sequences based on their indices, and the PUSCH is transmitted based on a modulation and coding scheme level associated with the PRACH preamble identifier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a 2-step RACH procedure is implemented, then access latency is reduced and communication efficiency is improved, but signal multiplexing complexity and resource allocation difficulty increase
Solution Approach 1:
The patent combines the PRACH preamble transmission and PUSCH data transmission into a single MsgA message, allowing both random access preamble and uplink data to be transmitted simultaneously in the 2-step RACH procedure. This merging reduces the number of steps and latency while requiring sophisticated multiplexing techniques to manage the combined signal structure.
Solution Approach 2:
The patent segments the MsgA message into distinct components including PRACH preamble, PUSCH data, and DM-RS reference signals, each with specific resource allocations and mapping relationships. This segmentation allows the receiver to separately process and identify each component while maintaining their integrated transmission structure.
2Productivity
If PUSCH and DM-RS are multiplexed in MsgA, then signal transmission efficiency is improved, but resource allocation complexity and mapping difficulty increase
Solution Approach 1:
The patent employs frequency-division multiplexing by allocating different frequency resources (resource blocks) to PUSCH and DM-RS within the MsgA message. The DM-RS is mapped to specific resource elements in the frequency domain, while PUSCH occupies other frequency resources, enabling simultaneous transmission with clear resource separation.
Solution Approach 2:
The patent applies different mapping rules and resource allocation strategies to different components within MsgA. The DM-RS is allocated specific resource elements with particular mapping patterns, while PUSCH uses different resource blocks and modulation schemes, optimizing each component's transmission characteristics for its specific function.
Data Source
AI summary
A method performed by a user equipment (UE) in a wireless communication system, and a device supporting same, that involves receiving configuration information related to a message A including a physical random access channel (PRACH) preamble and a physical uplink shared channel (PUSCH). The PRACH preamble is obtained from a plurality of PRACH preambles based on one of a first payload size and a second payload size which is carried by the PUSCH, each of the PRACH preambles is mapped to one of a first plurality of PUSCH occasions for the first payload size and a second plurality of PUSCH occasions for the second payload size, and the PUSCH is transmitted on a PUSCH occasion which belongs to one of the first plurality of PUSCH occasions and the second plurality of PUSCH occasions, to which the PRACH preamble is mapped.