Distributed Antenna System Master Reference Clock

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Solution Overview

Problem

Distributed Antenna Systems (DAS) face challenges in maintaining synchronization and clock stability across components, particularly in supporting multiple wireless services like TDD and FDD, where existing methods rely on GPS receivers for timing signals, which may not be robust or efficient.

Innovation Solution

A distributed antenna system that generates and distributes a master reference clock within the system, using network interfaces and remote antenna units to ensure all components are locked to a common clock, and allows the clock to be embedded in signals for synchronization with external devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If GPS receivers are used to provide timing signals for DAS components, then synchronization can be achieved, but the system becomes dependent on external GPS infrastructure which may not be robust or efficient in all environments

Engineering Contradiction:
Improvesynchronization reliabilityVSAvoidexternal dependency complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary reference clock signal that mediates between the master clock and slave clocks within the DAS. This internal reference clock serves as a mediator that distributes timing information throughout the system, replacing dependence on external GPS infrastructure with an internal timing distribution mechanism.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The DAS system generates its own master reference clock internally and uses it to synchronize all components. The system serves its own timing needs through the master clock unit that generates the reference clock signal, eliminating the need for external GPS timing infrastructure and making the system self-sufficient for synchronization purposes.

Inventive Principle:
Principle #25Self-service

2Adaptability or versatility

If multiple wireless services (TDD and FDD) are supported on a DAS, then service versatility is improved, but maintaining zero frequency shift and synchronization across all services becomes more difficult

Engineering Contradiction:
Improvewireless service versatilityVSAvoidfrequency shift precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The master reference clock generates a universal timing signal that serves all wireless services (both TDD and FDD) on the DAS. This single reference clock provides a common timing foundation that all service-specific components can use, enabling multi-service support while maintaining consistent frequency accuracy across all services.

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

Solution Approach 2:

The system maintains frequency precision by allowing different service components to derive their specific frequency parameters from the master reference clock. Each service can adjust its parameters (such as TDD uplink-downlink configuration or FDD carrier frequencies) while maintaining zero frequency shift relative to the common reference, enabling versatile service support with precise frequency control.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If a master reference clock is generated and distributed within the DAS, then synchronization and clock stability are improved, but the device complexity of the clocking system increases

Engineering Contradiction:
Improveclock stabilityVSAvoidclocking system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The clocking system is segmented into distinct functional units: a master clock unit that generates the reference signal, and multiple slave clock units that receive and lock to the reference. This segmentation allows the complex function of system-wide synchronization to be divided into manageable, modular components, reducing overall system complexity while maintaining stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges the timing generation and distribution functions into a unified reference clock system. The master clock and its distribution network are combined to form an integrated timing infrastructure that provides stable synchronization across all DAS components, achieving clock stability without proportionally increasing complexity through the merging of related functions.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3843284B1Master reference for base station network interface sourced from distributed antenna system
Publication Date: 2023.07.26 COMMSCOPE TECHNOLOGIES LLC
  • EP3843284B1 patent drawingFigure 1A
  • EP3843284B1 patent drawingFigure 1B
  • EP3843284B1 patent drawingFigure 1C

AI summary

A distributed antenna system (DAS) includes: first base station network interface unit that receives first downlink signals from first external device and converts them into first downlink data stream; second base station network interface unit that receives second downlink signals from second external device and them into second downlink data stream; first remote antenna unit communicatively coupled to first base station network interface unit that receives at least one of first downlink data stream and first downlink signal derived from first downlink data stream. First remote antenna unit has first radio frequency converter configured to convert at least one of first downlink data stream and first downlink signal derived from first downlink data stream into first radio frequency band signal and first radio frequency antenna that transmits first radio frequency band signal to first subscriber unit. DAS is configured to transmit a master reference clock to the first external device.