PRACH Resource Grouping for Reliable Random Access
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Solution Overview
Problem
Existing wireless communication systems face challenges in optimizing multiple PRACH transmissions, particularly in minimizing collision probability and resource inefficiencies, especially when UEs transmit multiple PRACH preambles.
Innovation Solution
A method where UEs receive RACH occasion configurations from a base station, select an SSB based on RSRP measurement, and determine a set of RO groups for multiple PRACH transmissions, optimizing resource allocation and minimizing collision probability by associating SSBs with ROs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple PRACH transmissions are performed without optimized resource configuration, then transmission reliability is improved, but resource utilization deteriorates and latency increases
Solution Approach 1:
The RACH occasions are divided into multiple groups, with each group containing a specific number of RACH occasions. This segmentation allows the system to efficiently manage multiple PRACH transmissions by allocating specific groups to different UEs or transmission attempts, thereby improving resource utilization while maintaining transmission reliability through structured organization of transmission opportunities
Solution Approach 2:
The patent implements dynamic selection of RACH occasion groups based on parameters such as SSB index, PRACH transmission attempt number, and RACH configuration. This dynamic approach allows the system to adaptively allocate resources for multiple PRACH transmissions, optimizing both reliability and resource utilization by making transmission decisions based on current channel conditions and system state
2Reliability
If multiple PRACH transmissions are performed without optimized resource configuration, then transmission reliability is improved, but latency increases
Solution Approach 1:
The system pre-configures multiple RACH occasion groups with different timing and resource allocations before actual PRACH transmissions occur. This preliminary configuration enables UEs to quickly select appropriate transmission opportunities without excessive processing delays, thereby maintaining transmission reliability through multiple attempts while minimizing latency through pre-planned resource allocation
3Device complexity
If RACH resources are allocated without group-based configuration, then resource allocation simplicity is maintained, but collision probability increases
Solution Approach 1:
RACH occasions are segmented into multiple groups, where each group can be independently configured and allocated. This segmentation reduces collision probability by distributing UEs across different groups and occasions, while the systematic grouping methodology maintains manageable complexity in the resource allocation process through structured organization
Solution Approach 2:
Different RACH occasion groups can be configured with different properties such as timing, frequency resources, and association with specific SSBs. This local differentiation allows the system to optimize resource allocation for specific transmission scenarios and reduce collisions in high-traffic conditions while maintaining overall system simplicity through standardized configuration patterns
Data Source
AI summary
In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a UE. The UE receives RACH occasion (RO) configurations from a base station. The RO configurations indicate associations between one or more SSBs and ROs. The UE selects one SSB from the one or more SSBs received from the base station. The UE determines a number of multiple PRACH transmissions based on a RSRP measurement of the selected SSB. The UE determines a set of RO groups associated with the selected SSB based on the RO configurations and the determined number of multiple PRACH transmissions. The UE transmits multiple PRACHs on a selected RO group from the determined set of RO groups.