Non-Uniform SSB to RACH Occasion Mapping for 5G Overload Prevention
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G NR and LTE, face challenges in efficiently managing random access channel (RACH) occasions due to uniform SSB to RO associations, leading to potential overloading and resource inefficiencies, especially in high-speed train scenarios where certain synchronization signal blocks (SSBs) are more frequently used.
Innovation Solution
Implementing a non-uniform or irregular SSB to RACH occasion association, where different SSBs are mapped to different numbers of RACH occasions based on their usage weights, allowing more RACH occasions for frequently used SSBs to prevent overloading and optimize resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If uniform SSB to RACH occasion association is used, then system complexity is reduced and ease of operation is improved, but resource utilization efficiency deteriorates and overloading occurs in high-speed train scenarios
Solution Approach 1:
The patent applies local quality by assigning different numbers of RACH occasions to different SSBs based on their specific usage patterns. High-speed train SSBs receive more RACH occasions while other SSBs receive fewer, creating a non-uniform distribution that optimizes resource allocation for specific scenarios without increasing overall system complexity
Solution Approach 2:
The patent changes the mapping parameter from uniform to non-uniform SSB to RACH occasion association. By adjusting the number of RACH occasions allocated to each SSB based on usage weights, the system adapts to different operational scenarios while maintaining manageable complexity through standardized procedures
2Device complexity
If uniform SSB to RACH occasion association is used, then device complexity is reduced, but the system becomes vulnerable to overloading in scenarios with concentrated access requests
Solution Approach 1:
The patent implements local quality by tailoring the number of RACH occasions to each SSB's specific needs. SSBs serving high-speed trains are allocated more RACH occasions to handle concentrated access requests, while other SSBs use fewer occasions, thereby preventing overloading in specific scenarios without requiring complex overall system redesign
Solution Approach 2:
The patent introduces dynamic adaptability by allowing the SSB to RACH occasion mapping to be adjusted based on usage patterns and scenario requirements. This dynamic approach enables the system to respond to varying load conditions while maintaining manageable device complexity through standardized mapping procedures
Data Source
AI summary
Certain aspects of the present disclosure provide techniques for random access channel (RACH) occasion assignment. A method that may be performed by a user equipment (UE) includes receiving, from a base station (BS), a plurality of synchronization signal blocks (SSBs), each SSB associated with a different transmit beam of the BS. The method further includes transmitting a random-access preamble on a first RACH occasion associated with a first SSB of the plurality of SSBs, wherein the first RACH occasion is one of a plurality of RACH occasions associated with the plurality of SSBs, wherein the first SSB is associated with a first number of the plurality of RACH occasions and a second SSB of the plurality of SSBs is associated with a second number of the plurality of RACH occasions, wherein the first number is different than the second number.