RACH Occasion Selection for System Information Requests
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The current 5G wireless communication system design for indicating RACH occasions for System Information (SI) message requests is inefficient, particularly when not all SSBs transmitted by a gNB can be mapped to RACH occasions in one PRACH configuration period, leading to varying numbers of PRACH configuration periods needed for mapping, which complicates the process.
Innovation Solution
The proposed solution involves defining a SI request period in multiples of association periods, where each association period is sequentially numbered, allowing for flexible mapping of SSBs to RACH occasions, and using configuration information signaled by the base station to enable UE to select appropriate RACH preambles and occasions for SI message requests, enabling reuse of dedicated preambles for different SI messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If all SSBs are mapped to RACH occasions in one PRACH configuration period, then the mapping process is simplified, but it becomes impossible when the number of SSBs exceeds the number of available RACH occasions
Solution Approach 1:
The patent divides the PRACH configuration into multiple periods (first PRACH configuration period, second PRACH configuration period, etc.) to accommodate the mapping of multiple SSBs that cannot be mapped within a single period. Each PRACH configuration period contains a set of RACH occasions, and by segmenting across multiple periods, the system can map a larger number of SSBs systematically.
Solution Approach 2:
The patent introduces a time dimension by using multiple PRACH configuration periods instead of attempting to map all SSBs within a single period. This transforms the problem from a spatial mapping constraint (within one period) to a temporal solution (across multiple periods), allowing the system to handle more SSBs by utilizing additional time resources.
2Adaptability or versatility
If multiple PRACH configuration periods are used for mapping SSBs, then all SSBs can be mapped to RACH occasions, but the configuration and management complexity increases
Solution Approach 1:
The patent employs periodic PRACH configuration periods where each period follows a structured pattern of mapping a specific set of SSBs to RACH occasions. This periodic approach allows the system to handle multiple SSBs in an organized, repeating cycle, reducing the perceived complexity by establishing a predictable, systematic configuration pattern that can be efficiently managed and tracked.
3Reliability
If dedicated preambles are allocated for each SI message, then SI message requests can be handled, but resource consumption increases
Solution Approach 1:
The patent enables dedicated preambles to serve multiple SI messages across different PRACH configuration periods. Instead of allocating unique dedicated preambles for each SI message, the same dedicated preamble can be reused in different periods for different SI messages, allowing the preamble resource to perform multiple functions and serve multiple purposes, thereby reducing overall resource consumption while maintaining reliable SI message request handling.
Data Source
AI summary
A method of a UE is provided. The method includes receiving, from a base station, configuration information for a system information (SI) request by higher layer signaling, the configuration information including information on a SI request period comprising of a number of association period; identifying information on a SI request resource corresponding to a SI message based on the configuration information, the information on the SI request resource including an index of an association period in the SI request period, information on a random access preamble, and information on a RACH occasion; and transmitting, to the base station, the SI request for the SI message based on the information on the SI request resource.