RACH Occasion Validation in 5G NR TDD Systems
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Solution Overview
Problem
In 5G New Radio (NR) systems, there is a challenge in validating the validity of a Random Access Channel (RACH) occasion, particularly when it straddles or extends across PRACH slot boundaries, due to the complexity of time-division duplex (TDD) configurations and the need for precise determination of uplink and downlink symbols.
Innovation Solution
A wireless communication device determines the validity of a RACH occasion by checking if it straddles or is located beyond a PRACH slot boundary, using criteria such as the type of symbols (uplink or downlink) in adjacent slots and the distance of the first symbol from the last downlink symbol or synchronization signal, with specific conditions defined for validity based on the presence or absence of a TDD common configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a RACH occasion straddles a PRACH slot boundary between first and second PRACH slots, then the RACH occasion can be positioned more flexibly in the time domain, but it becomes difficult to determine whether the RACH occasion is valid due to complex TDD configurations and symbol type uncertainties
Solution Approach 1:
The patent segments the RACH occasion validation process into distinct cases based on slot boundary straddling. It divides the validation logic into: (1) checking whether the RACH occasion is located in the first PRACH slot only, (2) checking whether it straddles into the second PRACH slot, and (3) checking whether it is located in the second PRACH slot only. This segmentation simplifies the overall validation complexity by handling each scenario with specific rules.
Solution Approach 2:
The patent applies preliminary action by performing advance checks on TDD common configuration and slot structure before validating the RACH occasion. It pre-determines the uplink/downlink nature of slots and symbols using TDD common configuration (if available) or fallback rules, and pre-identifies the PRACH slot boundary positions. This preliminary preparation enables simpler subsequent validation logic.
2Reliability
If strict validation rules are applied to ensure reliable communication, then system reliability improves, but the complexity of determining symbol types and slot configurations increases
Solution Approach 1:
The patent applies local quality by providing different validation rules for different local contexts. Specifically: (1) If TDD common configuration is received, use that configuration to determine slot and symbol types; (2) If no TDD common configuration is received, use fallback rules based on SS/PBCH block positions and predefined patterns. This contextual approach ensures reliable validation while adapting to available information.
Solution Approach 2:
The patent inverts the traditional validation approach by first determining the validity of the RACH occasion based on slot boundary straddling conditions, and then using that validity determination to guide subsequent processing. Instead of trying to resolve all configuration ambiguities first, it validates the RACH occasion structure upfront and uses the validity result to proceed with communication protocols.
Data Source
AI summary
Presented are systems and methods for validating a random access channel (RACH) occasion. A wireless communication device may receive a RACH signaling from a wireless communication node. The wireless communication device may determine whether a time-division duplex (TDD) common configuration is received at the wireless communication device.