Two-Step Random Access PUSCH SCS Alignment for Larger Cells
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The four-step random access procedure in NR systems is inefficient for larger cells due to the need for timing advance, leading to increased cyclic prefix requirements, and there is a lack of effective solutions for determining the numerology of preamble and PUSCH in two-step random access procedures.
Innovation Solution
Introduce new parameters in RRC messages or BWP to indicate the subcarrier spacing (SCS) for preamble and PUSCH in two-step random access, aligning it with the SCS of message 1 or message 3 in four-step procedures to facilitate efficient communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If four-step random access procedure is used in larger cells, then timing accuracy can be maintained within cyclic prefix, but random access efficiency deteriorates and procedure complexity increases
Solution Approach 1:
The patent segments the traditional four-step random access procedure into a simplified two-step procedure by combining message 1 and message 3 into a single message A, and combining message 2 and message 4 into message B. This segmentation reduces the number of interaction steps while maintaining timing synchronization through the integrated structure of message A containing both preamble and PUSCH with configured SCS values.
Solution Approach 2:
The patent applies preliminary action by pre-configuring the subcarrier spacing (SCS) values for both preamble and PUSCH in message A before the random access procedure begins. The base station provides SCS configuration through RRC messages or system information, allowing the terminal to perform timing advance and synchronization without requiring separate timing negotiation steps during the access procedure.
2Measurement precision
If cyclic prefix is increased to maintain timing accuracy in larger cells, then timing synchronization is improved, but system complexity and resource overhead increase
Solution Approach 1:
The patent changes the subcarrier spacing parameter for preamble and PUSCH to achieve timing synchronization without requiring increased cyclic prefix length. By configuring appropriate SCS values through RRC messages or system information, the system maintains timing accuracy in larger cells while avoiding the complexity and resource overhead associated with extended cyclic prefixes.
3Adaptability or versatility
If separate SCS configuration is provided for preamble and PUSCH, then communication flexibility is improved, but signaling overhead and configuration complexity increase
Solution Approach 1:
The patent segments the SCS configuration into distinct parameters for preamble and PUSCH within message A, allowing independent configuration of each component's subcarrier spacing. This segmentation enables flexible communication by permitting different SCS values for different parts of message A, while the configuration is efficiently conveyed through existing RRC message structures or system information blocks.
Data Source
AI summary
Methods, a base station, and a terminal device for a two-step random access procedure are disclosed. The base station transmits a first message indicating a subcarrier spacing (SCS) of a physical uplink shared channel (PUSCH) which is to be used for a second message in the two-step random access procedure, through an air interface. The SCS of the PUSCH is same as an SCS used for message 3 in a four-step random access procedure. The base station receives the second message based on the SCS of the PUSCH through the air interface in the two-step random access procedure.