5G NR Random Access Coexistence With 2-Step and 4-Step RACH

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Solution Overview

Problem

There is a need for improved methods and apparatuses to support the co-existence of different types of random access procedures in wireless communication systems, particularly in 5G NR networks, to enhance communication efficiency and reliability.

Innovation Solution

The proposed solution involves configuring user equipment (UE) and base stations to operate in networks supporting both 2-step and 4-step random access by receiving and transmitting specific messages based on configured random access channel occasions, including preambles and payloads, to facilitate seamless communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the network supports both 2-step random access and 4-step random access procedures, then the adaptability and versatility of the random access mechanism is improved, but the device complexity and configuration management become more complex

Engineering Contradiction:

Improverandom access type supportVSAvoidconfiguration management

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the random access procedure into two distinct types (2-step and 4-step) with separate configuration parameters. The base station configures different RACH occasions, preambles, and message structures for each type, allowing independent optimization and management of each random access procedure while supporting both simultaneously

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The base station and user equipment are designed with multi-functional capabilities to handle both 2-step and 4-step random access procedures. The configuration information structure is universal enough to accommodate parameters for both types, enabling the system to adapt to different random access requirements without requiring separate dedicated systems

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If configuration information includes RACH occasions for both 2-step and 4-step random access, then the co-existence capability is improved, but the loss of information and configuration overhead increase

Engineering Contradiction:

Improveco-existence capabilityVSAvoidconfiguration overhead

Core Design Contradiction:

Adaptability or versatilityVSLoss of information

Solution Approach 1:

The configuration information is segmented into type-specific parameters. The base station transmits separate configuration sets for 2-step RACH (including msgA PUSCH parameters) and 4-step RACH (including PRACH parameters), allowing the UE to selectively process only the relevant configuration for its current random access type, reducing unnecessary information processing overhead

Inventive Principle:

Principle #1Segmentation

Data Source

PatentEP3925387B1Techniques for supporting co-existence between 2-step random access and 4-step random access

Publication Date: 2025.12.24 QUALCOMM INC

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AI summary

Aspects of the present disclosure provide techniques and apparatus for wireless communication. In one aspect, a method is provided which may be performed by a wireless device such as a user equipment (UE) in a network supporting co-existence of a first type of random access and a second type of random access, which may be associated with different latency, overhead, quality of service (QoS), energy efficiency, and/or spectral efficiency.