Joint RACH Processing for Cell-Edge Network Access

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Solution Overview

Problem

Existing techniques for network access do not consider the joint-processing capabilities of user equipment-coordination sets (UECS) or base station coordination sets (ACS) to improve the performance of Random Access Channel (RACH) communications, particularly for UEs operating at cell edges with weak signal quality and in higher frequency bands.

Innovation Solution

Implementing joint-transmission and/or joint-reception by UECS or ACS to enhance RACH communications, including coordinated RACH resource group configurations, timing, and preamble sequences, with UEs caching resource configurations for later use and base stations coordinating to manage joint-processing latencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing network access techniques are used, then device simplicity is maintained, but RACH communication performance degrades for cell edge UEs and higher frequency bands

Engineering Contradiction:
ImproveRACH communication performanceVSAvoidcoordination set processing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple base stations into a coordination set (ACS) that jointly processes RACH communications. Multiple base stations coordinate their reception and processing of random access preambles, combining their signal processing capabilities to improve detection performance for cell edge UEs and higher frequency bands where signal quality is degraded.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent segments the network into coordination sets with designated master and slave base stations. This segmentation allows distributed processing where slave base stations forward received signals to the master base station, which performs joint processing. This reduces individual base station complexity while maintaining improved RACH performance through coordinated processing.

Inventive Principle:
Principle #1Segmentation

2Length of stationary object

If joint-processing is implemented to improve link budget, then geographic range is extended, but processing latency increases

Engineering Contradiction:
Improvegeographic rangeVSAvoidcoordination processing latency
Core Design Contradiction:
Length of stationary objectVSLoss of time

Solution Approach 1:

The patent implements preliminary action by having slave base stations forward received RACH signals to the master base station in advance of final processing. This preliminary signal transfer allows the master base station to perform joint processing without waiting for individual base stations to complete separate processing, reducing overall latency while maintaining extended geographic range coverage.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The master base station acts as an intermediary that coordinates signal reception and processing among multiple base stations. It receives signals from slave base stations, performs joint processing, and generates the final RACH detection result. This intermediary role streamlines the coordination process and reduces processing latency compared to distributed processing architectures.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If coordinated resource configuration is used, then RACH communication reliability improves, but network configuration complexity increases

Engineering Contradiction:
Improvenetwork access reliabilityVSAvoidresource configuration management
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements universal resource configuration where a single RACH resource group configuration is shared and reused across multiple coordination sets. Instead of configuring separate resources for each base station or coordination set, the same preamble sequences, time resources, and frequency resources are universally applied, simplifying network configuration management while maintaining improved reliability through coordinated processing.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent applies homogeneity by using identical RACH resource configurations across all base stations in the coordination set. All base stations use the same preamble sequences, time slots, and frequency resources for RACH communications, which simplifies configuration management and reduces the complexity of tracking and managing differentiated resource allocations across multiple base stations.

Inventive Principle:
Principle #33Homogeneity

Data Source

PatentEP4085721B1Joint-processing of random access channel communications
Publication Date: 2026.04.08 GOOGLE LLC
  • EP4085721B1 patent drawingFigure 1
  • EP4085721B1 patent drawingFigure 2
  • EP4085721B1 patent drawingFigure 3

AI summary

Techniques and apparatuses are described for joint-processing of random access channel communications to improve the reliability and/or the geographic range of a random access procedure for a user equipment (110). Joint-processing, including joint-transmission and/or joint-reception, by a user equipment-coordination set (108) on behalf of a single user equipment (110), or by an Active Coordination Set of base stations (120) with the single user equipment (110), can improve the link budget of Random Access Channel communications and facilitate network access for a user equipment (110) at a greater distance from a base station (121) or in the face of challenging channel conditions.