Random Access Messaging Architecture for Lower-Latency Two-Step RACH

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Solution Overview

Problem

Existing wireless communication systems face inefficiencies in network resource allocation due to contention-based random access, leading to increased latency and reduced data network performance.

Innovation Solution

Implementing a two-step random access channel (RACH) protocol that combines the UE's message transmission and the basestation's response, using distinct message architectures to differentiate between different types of random access messages, thereby reducing latency and improving network performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If contention-based random access is used for network resource allocation, then network resource management flexibility is improved, but latency increases and data network performance deteriorates

Engineering Contradiction:
Improvenetwork resource management flexibilityVSAvoidlatency
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The random access procedure is segmented into two distinct steps: (1) UE transmits a first message containing preamble and payload information, (2) basestation responds with a second message containing grant and backoff indicator. This segmentation allows parallel processing of multiple UEs' requests and responses, reducing collision probability and latency while maintaining the flexibility of contention-based access.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The basestation transmits backoff indicators in advance within the second message to manage UE retransmission timing before actual collisions occur. This preliminary action allows UEs to adjust their transmission schedule proactively, reducing latency and improving network performance while preserving the random access mechanism's adaptability.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If traditional four-step RACH protocol is used, then message transmission completeness is improved, but channel occupancy time increases

Engineering Contradiction:
Improvemessage transmission completenessVSAvoidchannel occupancy time
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent merges the UE's first message (containing preamble and payload) and the basestation's second message (containing grant and backoff indicator) into a single integrated random access response structure. This combining approach reduces the number of separate transmission phases, thereby reducing channel occupancy time while maintaining message transmission completeness through proper message architecture and processing.

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If multiple random access message types are transmitted without clear differentiation, then transmission efficiency is improved, but message identification accuracy deteriorates

Engineering Contradiction:
Improvetransmission efficiencyVSAvoidmessage identification accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

Different random access message types are differentiated using distinct local characteristics in the message architecture, including specific header formats, payload structures, and identification fields. This local quality differentiation allows UEs to efficiently identify message types (e.g., success RAR, fallback RAR, backoff indicator) through localized feature recognition, maintaining both transmission efficiency and identification accuracy.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4005325B1Architecture for random access messaging
Publication Date: 2025.07.02 ZTE CORP
  • EP4005325B1 patent drawingFigure 1
  • EP4005325B1 patent drawingFigure 2
  • EP4005325B1 patent drawingFigure 3

AI summary

User equipment may request to communicate with a basestation over a contention-based wireless communication channel. The basestation and the user equipment may perform a multiple-step random access protocol to determine whether the user equipment may communicate over the wireless communication channel. The architecture, e.g., the fields and structure of the messages sent by the basestation may indicate the content and type of those same messages.