MsgA Preamble-to-PRU Mapping for Flexible Two-Step RACH
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Solution Overview
Problem
Existing 5G NR technologies face challenges in efficiently supporting diverse payload sizes and coverage requirements for msgA transmissions in two-step random access procedures, particularly in terms of resource allocation and collision probability, especially in scenarios involving multiple UEs with varying payload sizes and modulation coding schemes.
Innovation Solution
A one-to-many mapping arrangement is introduced between preambles and PRUs, allowing for flexible resource allocation by grouping PRUs into sets based on different payload sizes and enabling features like UCI piggybacking, frequency hopping, and multiple-slot repetition to enhance coverage and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple preambles are mapped to the same PRU group, then resource utilization efficiency is improved, but collision probability increases
Solution Approach 1:
The patent segments the PRU groups into different sets based on payload size categories. Small payload UEs are mapped to one set of PRU groups while large payload UEs are mapped to another set. This segmentation prevents collisions between different payload types while maintaining efficient resource utilization within each segment.
Solution Approach 2:
Different mapping strategies are applied to different UE types based on their payload characteristics. The system applies localized quality control by configuring separate PRU group sets for small and large payload UEs, allowing optimized resource allocation for each local group while avoiding global conflicts.
2Device complexity
If fixed PRU allocation is used for all payload sizes, then device complexity is reduced, but adaptability to diverse payload sizes deteriorates
Solution Approach 1:
The patent introduces dynamic adaptability through configurable offset values that can be adjusted based on payload size. The mapping between preambles and PRU groups is not fixed but can be dynamically configured using offset parameters, allowing the system to adapt to different payload requirements while maintaining a relatively simple base structure.
Solution Approach 2:
The system uses parameter changes through configurable offset values to accommodate different payload sizes. By changing the offset parameters in the mapping configuration, the system can adapt to various payload scenarios without requiring completely different allocation mechanisms, thus maintaining simplicity while achieving versatility.
3Reliability
If larger PRU groups are allocated to all UEs, then coverage is improved, but resource utilization efficiency deteriorates
Solution Approach 1:
The patent segments UEs into small and large payload categories and allocates different PRU group sizes to each segment. Small payload UEs are assigned to smaller PRU groups while large payload UEs receive larger PRU groups. This segmentation ensures that coverage is adequate for each UE type without wasting resources on unnecessarily large allocations for small payloads.
Solution Approach 2:
Different PRU group sizes are allocated locally to different UE types based on their specific coverage and payload requirements. This local quality approach ensures that each UE type receives the minimum necessary resources for reliable communication, avoiding the inefficiency of uniform over-allocation.
Data Source
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AI summary
Aspects are provided to support payloads for msgA transmission in a two-step random access (RACH) procedure by providing a one-to-many mapping arrangement between preambles and physical uplink shared channel (PUSCH) resource units (PRUs). A preamble is determined by the UE which is mapped to one or more groups of PRUs to support piggybacking of uplink control information (UCI), frequency hopping on PUSCH, and multiple-slot repetition for msgA transmissions. By piggybacking UCI to a payload in msgA, flexibility may be provided in the selection of MCS and waveform as well as resource allocation for demodulation reference signals (DMRS) and PUSCH in PRUs. Moreover, by allowing a payload to hop to different frequencies on PUSCH during the transmission of msgA, a gain in frequency diversity and interference averaging may be provided, and by enabling a payload to repeat across multiple slots in msgA transmission, coverage enhancement and/or reliability may be increased.