PRACH Occasion Mapping for 5G NR Random Access
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Solution Overview
Problem
The existing framework for determining available slots and random access channel occasions for PRACH repetitions in 5G NR is suboptimal, leading to inefficient PRACH preamble transmissions and increased collision probabilities.
Innovation Solution
A method and apparatus that map synchronization signal block indices to random access channel occasions based on a time extension, allowing for flexible mapping in both time and frequency domains, prioritizing back-to-back repetitions while limiting the burden on the network receiver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the existing framework for determining available slots and random access channel occasions is used, then the system maintains simplicity in implementation, but PRACH detection performance deteriorates and collision probabilities increase
Solution Approach 1:
The patent applies dynamics by making the mapping framework configurable and adaptable. The gNB can dynamically adjust the mapping between SSB indices and ROs based on current network conditions, allowing the system to optimize PRACH detection performance while managing complexity through flexible, condition-based configuration rather than fixed rigid structures
Solution Approach 2:
The patent utilizes parameter changes by modifying the mapping parameters (such as the association between SSB indices and ROs, and the configuration of time extensions) to optimize PRACH repetitions. By changing these parameters based on network conditions, the system improves detection performance without requiring a complete restructuring of the framework
2Reliability
If PRACH occasions are spread out in the time domain, then collision probabilities are reduced, but the efficiency of PRACH repetitions deteriorates
Solution Approach 1:
The patent applies segmentation by dividing PRACH occasions into distinct groups or sets associated with different SSB indices. This allows the system to concentrate repetitions within specific time segments (improving efficiency) while maintaining separation between different SSB-associated ROs (reducing collisions), thus resolving the contradiction through structured segmentation
Solution Approach 2:
The patent uses preliminary action by pre-configuring the mapping between SSB indices and ROs, and pre-defining time extension parameters. This allows the UE to efficiently determine repetition opportunities in advance without real-time complexity, improving both collision avoidance and repetition efficiency through预先 established rules
3Reliability
If flexible mapping of SSB indices to ROs is implemented, then PRACH detection performance is improved, but the burden on the network receiver increases
Solution Approach 1:
The patent applies feedback by using the predetermined mapping configuration as a common reference between gNB and UE. The gNB configures the mapping parameters, and both sides use this predetermined information to independently determine the correct ROs for repetitions, eliminating the need for complex real-time feedback mechanisms while maintaining flexible, optimized mapping
Solution Approach 2:
The patent utilizes self-service by enabling the UE to autonomously determine the correct ROs for PRACH repetitions using the predetermined mapping configuration. The UE independently calculates which ROs to use based on the configured parameters without requiring additional network assistance or complex receiver processing, thus improving detection performance without increasing network receiver burden
Data Source
AI summary
In accordance with example embodiments of the invention there is at least a method and apparatus to perform determining, by a network device of a communication network, random access channel parameters for random access to the communication network; based on the random access channel parameters, deriving a set of random access channel occasions in a time domain and frequency domain; based on the derived set of random access channel occasions, mapping or causing mapping of at least one synchronization signal block index to a number of at least one random access channel occasion of the set of random access channel occasions in at least one of the time domain or the frequency domain, wherein the mapping is based on a; and sending towards a network node of the communication network Msg1 preamble repetitions using at least part of the number of at least one random access channel occasions.