RNTI Allocation for Random Access in 5G Systems
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Solution Overview
Problem
In mobile communication systems, the existing methods for calculating radio network temporary identifiers (RNTIs) in random access procedures face challenges in avoiding overlapping values, especially when notifying request features, which can lead to a shortage of allocatable RNTIs due to the upper limit defined in technical specifications.
Innovation Solution
A communication apparatus and method that select and calculate RNTIs using designated PRACH time-frequency index sets and specific calculation formulas to ensure the RNTIs fall within non-overlapping value ranges, allowing for appropriate identification of random access responses even when request features differ.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the existing RNTI calculation method is used to notify request features, then the upper limit of allocatable RNTIs is reached, but this leads to a shortage of RNTIs and potential overlapping values
Solution Approach 1:
The RNTI value range is segmented into multiple non-overlapping ranges, each corresponding to different request features. By dividing the total RNTI space into distinct segments (e.g., different offsets for different features), the system can notify multiple features simultaneously without causing value overlaps, thereby resolving the contradiction between feature notification capability and RNTI availability.
2Adaptability or versatility
If the RNTI value range is expanded to accommodate more features, then more features can be notified, but this increases the risk of overlapping with existing RNTI ranges
Solution Approach 1:
Different local quality characteristics (distinct RNTI value ranges with specific offsets) are assigned to different request features. Each feature has its own dedicated RNTI range, ensuring that the local property of each feature's identifier is unique and non-overlapping, thereby maintaining identification accuracy while accommodating multiple features.
3Adaptability or versatility
If multiple PRACH time-frequency index sets are configured for different features, then feature identification is improved, but this increases system complexity
Solution Approach 1:
Multiple PRACH time-frequency index sets are pre-configured and associated with different request features before the random access procedure begins. The correspondence between index sets and features is established in advance, allowing the terminal to quickly select the appropriate index set based on its requested feature without complex real-time calculations, thereby reducing operational complexity while maintaining high feature identification capability.
Data Source
AI summary
A communication apparatus having at least one of a plurality of features defined in a mobile communication system, the communication apparatus comprising: a receiver configured to receive, from a base station, a system information block including information indicating a plurality of resources of random access and information indicating correspondence between each of the plurality of resources of the random access and a combination of one or more features; and a controller configured to select, from the plurality of resources of the random access, a resource of the random access corresponding to the at least one of the plurality of features which the communication apparatus has, on a basis of the information indicating the correspondence, and to calculate a random access-radio network temporary identifier (RA-RNTI) used in a random access procedure on a basis of the selected resource of the random access. The one or more features includes at least one of a reduced capability (RedCap) feature, a small data feature, a network slicing feature, and a feature for repetition of a message3 (MSG3).