Initial Cell Access Signaling for Reduced-Bandwidth UEs
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently allowing user equipment (UE) with reduced capability to perform initial cell access due to limitations in bandwidth support, necessitating improved methods for cell access in 3GPP-based systems.
Innovation Solution
A method and apparatus for initial cell access in a 3GPP-based wireless communication system, where a UE with reduced capability determines access based on a reserved bit state in system information block 1 (SIB1)-scheduling information, allowing it to perform a residual access procedure or search for a second cell, and obtains scheduling information specific to its capability type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a UE with reduced capability attempts to access a cell in existing wireless communication systems, then the UE can perform cell access procedures, but the access efficiency is reduced due to bandwidth support limitations
Solution Approach 1:
The patent applies local quality by providing differentiated system information for different UE types. Specifically, SIB1 contains a reserved bit (e.g., bit 6 of dcch-Config) that indicates whether the cell supports reduced capability UEs, and separate SIB1-R is provided specifically for RedCap UEs. This localized information structure allows cells to selectively support different UE capabilities without affecting other UEs, thereby improving access efficiency for RedCap UEs while maintaining compatibility with normal UEs.
Solution Approach 2:
The patent changes the parameter structure of system information by introducing a reserved bit state in SIB1-scheduling information that indicates RedCap support. Additionally, separate SIB1-R messages are introduced with RedCap-specific parameters such as rach-ConfigRedCap for random access configuration. These parameter changes enable RedCap UEs to efficiently determine cell compatibility and access procedures tailored to their bandwidth constraints.
2Adaptability or versatility
If reserved bit states are utilized in SIB1-scheduling information for RedCap indication, then access determination for reduced capability UEs is enabled, but the complexity of information processing increases
Solution Approach 1:
The patent extracts RedCap-specific information from the general SIB1 structure by utilizing a reserved bit (e.g., bit 6 of dcch-Config) specifically for RedCap indication. Additionally, SIB1-R is extracted as a separate message containing only RedCap-relevant parameters. This extraction approach allows RedCap UEs to quickly identify compatible cells and obtain necessary configuration without processing the entire SIB1 message, thereby reducing information processing complexity while maintaining adaptability.
Solution Approach 2:
The patent implements preliminary action by providing RedCap support indication in advance through the reserved bit in SIB1-scheduling information. RedCap UEs can determine cell compatibility before attempting full access procedures. This preliminary indication prevents unnecessary processing of incompatible cells and reduces overall information processing complexity by filtering out non-supportive cells early in the cell search process.
3Adaptability or versatility
If separate SIB1-R is provided for RedCap UEs, then specific scheduling information for reduced capability UEs is obtained, but the quantity of system information transmitted increases
Solution Approach 1:
The patent segments system information into multiple parts: SIB1 for normal UEs and SIB1-R for RedCap UEs. SIB1-R contains only RedCap-specific parameters such as rach-ConfigRedCap, whereas normal UEs only need to process SIB1. This segmentation allows each UE type to receive and process only the information relevant to their capabilities, thereby providing capability-specific scheduling information while minimizing the actual information volume each UE must handle.
Solution Approach 2:
The patent applies partial action by providing SIB1-R only to RedCap UEs that specifically need it, while normal UEs continue to use standard SIB1. The reserved bit in SIB1-scheduling information enables this selective provision. This approach ensures that RedCap UEs obtain necessary capability-specific information without normal UEs being burdened with processing redundant SIB1-R messages, thus balancing information provision with transmission efficiency.
Data Source
AI summary
A terminal for performing an initial cell access, according to an embodiment of the present disclosure, receives a PBCH signal of a first cell via a cell search, receives SIB1-scheduling information on a CSS set related to the PBCH signal, and determines whether to perform a remaining access procedure on the first cell, on the basis of the SIB1-scheduling information, wherein the terminal is a second type terminal in which the capability is reduced to support a bandwidth narrower than that of a first type terminal, and the terminal may determine, as the second type terminal, whether an access to the first cell is allowed, on the basis of the state of a bit reserved so as not to be used by the first type terminal within the SIB1-scheduling information.