Wireless Fronthaul Control Message Multiplexing

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Solution Overview

Problem

Existing wireless communication systems face challenges in efficiently managing radio resource control and fronthaul control over wireless fronthaul links, particularly in densely deployed millimeter wave (mmW) base stations where wireline connections are limited.

Innovation Solution

The described techniques involve establishing multiple radio bearers (RBs) between a relay and a distributed unit (DU) or central unit (CU) to transmit different sets of control messages. These include signaling radio bearers (SRBs) and data radio bearers (DRBs) configured to carry control messages for access radio links and fronthaul configurations, respectively, allowing for efficient multiplexing and transmission of control messages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wireline links are used for backhaul/fronthaul communications, then reliability and stability are improved, but deployment flexibility and cost are worsened in densely spaced base station systems

Engineering Contradiction:
Improvebackhaul link reliabilityVSAvoiddeployment flexibility
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces wireline mechanical connections with wireless communication links for backhaul and fronthaul connections. Base stations use wireless interfaces (e.g., microwave, mmWave) to establish backhaul links with other base stations and fronthaul links with central units, eliminating the need for physical cable infrastructure and enabling rapid deployment in dense networks.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent enables base stations to perform multiple functions: they serve as access points for user equipment, relay nodes for other base stations, and distributed units for centralized control. This multi-functionality allows wireless links to simultaneously support backhaul, fronthaul, and access communications, improving deployment flexibility without sacrificing reliability.

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

2Ease of operation

If separate control planes are established for access links and fronthaul links, then control message management is improved, but device complexity and signaling overhead are worsened

Engineering Contradiction:
Improvecontrol message managementVSAvoidcontrol plane complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent segments control messages into distinct types: access control messages (for managing user equipment connections) and fronthaul control messages (for managing wireless backhaul links). Each message type is handled by dedicated protocol layers and processing logic, allowing independent optimization and management of each control plane without increasing overall system complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a control message routing mechanism that acts as an intermediary between access and fronthaul control planes. The base station controller routes access control messages to the appropriate access protocols and fronthaul control messages to the wireless link management protocols, enabling clear separation of control functions while maintaining integrated operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If wireless fronthaul links are used in mmW systems, then deployment cost and flexibility are improved, but link capacity and stability are worsened due to signal attenuation and interference

Engineering Contradiction:
Improvedeployment costVSAvoidwireless link stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent implements dynamic link adaptation for wireless fronthaul connections. The base stations continuously monitor link quality metrics (signal-to-noise ratio, bit error rate, attenuation) and dynamically adjust transmission parameters including power levels, modulation schemes, and coding rates. This dynamic adaptation maintains link stability despite mmWave propagation challenges while keeping deployment costs low.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs preliminary link establishment and quality assessment procedures before activating fronthaul connections. The base stations perform initial synchronization, channel estimation, and link quality measurements to establish reliable wireless links proactively, preventing connectivity issues before they affect system operation and reducing the need for expensive infrastructure.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3665942B1Techniques for providing radio resource control and fronthaul control on a wireless fronthaul link
Publication Date: 2025.06.18 QUALCOMM INC
  • EP3665942B1 patent drawingFigure 1
  • EP3665942B1 patent drawingFigure 2
  • EP3665942B1 patent drawingFigure 3A~3B

AI summary

Methods, systems, and devices for wireless communication are described that provide for transmitting different sets of control messages through a relay to a central unit (CU) and a core network of a wireless communications system. The different sets of control messages may include a first set of control messages for an access radio link between the relay and the CU and a second set of control messages for a fronthaul radio link between the relay and the CU. Techniques may include multiplexing of messages on a radio bearer (RB), establishment of separate RBs for different control messages, and encapsulation of one type of control message for transmission with the other type of control message.