Two-Step RACH Preamble Resource Ordering and Scrambling Identifier Generation

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Solution Overview

Problem

Current wireless communication systems face challenges in efficiently configuring physical uplink shared channel (PUSCH) resources and generating scrambling identifiers for the two-step random access channel (RACH) procedure, leading to high latency and increased collision probabilities, especially in 5G/NR wireless systems.

Innovation Solution

The proposed solution involves a deterministic or semi-persistent ordering procedure for preamble and PUSCH resources, which simplifies configuration through system information and RRC signaling, reduces decoding complexity, and generates scrambling identifiers to mitigate inter-cell and intra-cell interference, thereby reducing collision probabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional RACH procedures are used in 5G/NR systems, then the random access process can be performed, but high latency and increased collision probabilities occur

Engineering Contradiction:

Improvecollision probabilityVSAvoidlatency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-configuring PUSCH resources and generating scrambling identifiers before the actual RACH procedure execution. The base station prepares the resource configuration and scrambling ID generation rules in advance, and the UE calculates the scrambling identifier beforehand based on these pre-configured parameters, reducing real-time processing latency and collision probability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamics by making the scrambling identifier generation adaptive to different RACH configurations. The scrambling ID is dynamically generated based on parameters such as RO index, preamble index, and PUSCH resource index, allowing the system to adapt to varying channel conditions and traffic patterns, thereby reducing collisions and latency

Inventive Principle:

Principle #15Dynamics

2Manufacturing precision

If detailed PUSCH resource configuration is provided through signaling, then resource allocation accuracy is improved, but signaling overhead increases

Engineering Contradiction:

Improveresource configuration accuracyVSAvoidsignaling overhead

Core Design Contradiction:

Manufacturing precisionVSLoss of information

Solution Approach 1:

The patent applies self-service by enabling the UE to autonomously generate the scrambling identifier using pre-configured parameters and a deterministic formula. Instead of the base station explicitly signaling the scrambling ID, the UE independently calculates it based on available configuration information, significantly reducing signaling overhead while maintaining precise resource allocation

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent uses parameter changes by transforming the scrambling identifier from a separately signaled parameter to a derived parameter. The scrambling ID is generated by changing the form of representation from explicit signaling to mathematical derivation using parameters like RO index, preamble index, and PUSCH resource index, reducing signaling overhead while preserving configuration accuracy

Inventive Principle:

Principle #35Parameter changes

3Reliability

If complex scrambling identifier generation methods are used, then interference mitigation is improved, but decoding complexity increases

Engineering Contradiction:

Improveinterference mitigationVSAvoiddecoding complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical/scanning-based interference mitigation methods with a mathematical substitution approach. The scrambling identifier is generated through a deterministic mathematical formula using available parameters, substituting complex signal processing operations with simpler arithmetic calculations, thereby reducing decoding complexity while maintaining interference mitigation effectiveness

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS20220408493A1Preamble and physical uplink shared channel resource ordering and scrambling identifier generation for two-step random access channel procedure

Publication Date: 2022.12.22 QUALCOMM INC

AI summary

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive, from a base station, a random access channel (RACH) occasion (RO) configuration that includes information related to ordered preamble resources. The UE may generate a preamble resource index according to various parameters selected based on the RO configuration information that relates to the ordered preamble resources. The UE may generate an uplink RACH message that includes a preamble based at least in part on the preamble resource index and a payload associated with a physical uplink shared channel (PUSCH) resource unit (PRU) mapped to the preamble resource index. After decoding the uplink RACH message, the base station may send a response message including scrambled downlink control information (e.g., based on a scrambling identifier or payload information associated with the uplink RACH message). Numerous other aspects are provided.