Two-Step Random Access Occasion Mapping for Low-Latency Wireless Links
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently configuring random access procedures, particularly in two-step RACH procedures, due to unsuitable preamble and payload occasions, leading to high transmission latency and undesirable link quality.
Innovation Solution
Configuring random access occasions by associating preamble and payload transmissions with synchronization signal block (SSB) beams, ensuring threshold link quality and reducing latency through proximity-based multiplexing, and determining suitable occasions for transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If random access procedures use traditional configuration methods, then system compatibility is maintained, but transmission latency increases and link quality deteriorates
Solution Approach 1:
The random access procedure is divided into two separate steps: MsgA transmission (containing preamble and payload) and MsgB reception (containing random access response and contention resolution). This segmentation allows independent optimization of each message transmission, enabling the UE to select appropriate occasions for preamble and payload based on SSB beam associations, thereby reducing transmission latency while maintaining link quality through targeted retransmissions.
Solution Approach 2:
The patent introduces dynamic occasion selection where the UE determines specific preamble occasions and payload occasions based on SSB beam measurements and associations. Instead of using fixed configurations, the system dynamically adapts the random access timing and resources according to current channel conditions and beam quality, reducing latency by selecting the most suitable transmission opportunities while ensuring link quality through beam-specific optimizations.
2Reliability
If multiple preamble and payload occasions are configured for each SSB beam, then link quality improves through selective transmission, but device complexity increases
Solution Approach 1:
The patent establishes universal association rules that map multiple SSB beams to multiple preamble occasions and payload occasions using consistent indexing mechanisms. The same association principles apply regardless of the number of beams or occasions, allowing the system to scale while maintaining manageable complexity. The UE uses standardized procedures to determine appropriate occasions based on SSB indices and configured associations, avoiding the need for complex beam-specific configurations.
Solution Approach 2:
The system manages complexity by parameterizing the association between SSB beams and random access occasions through configurable parameters such as occasion periods, offsets, and mapping rules. Instead of hardcoding complex relationships, the patent uses parameter-driven configurations that can be adjusted through signaling, allowing the network to optimize link quality by configuring multiple occasions while keeping the underlying mechanism simple and uniform across different deployment scenarios.
Data Source
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AI summary
Aspects described herein relate to configuring and selecting preamble and payload occasions for performing two-step random access procedures. Configurations on preamble occasions, payload occasions, association pattern between the occasions and synchronization signal block (SSB) beams, and the rules for selecting preamble and payload occasions for random access message transmission can be determined by the network and signaled to user equipment (UE). Based on the configurations and rules, UE can measure the link level quality and select possible preamble and payload occasions for one or more SSB beams achieving a threshold signal quality. Sets of one or more preamble occasions and one or more payload occasions can be further determined based on whether the preamble and payload occasion (s) can achieve a threshold transmission latency. The one or more preamble occasions and one or more payload occasions can be used to transmit random access messages in the two-step random access procedure.