Clock Priority Chain Level Systems for Distributed Antenna Networks

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Solution Overview

Problem

In multi-host unit distributed antenna systems, it is unclear which host unit provides the Master Clock, and if a host unit providing the Master Clock fails, the network's functionality is compromised, as there is no clear mechanism for automatic recovery and priority determination.

Innovation Solution

The system prioritizes host units based on their Master Clock Priority Level (MCPL) and Network Chain Level (NCL) values, allowing automatic selection of a backup host unit to provide the Master Clock and ensuring network stability through a chain-level priority mechanism, with conflict detection and adaptation algorithms to manage changes and failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single host unit provides the Master Clock, then the system has a clear timing reference, but the network becomes vulnerable to single-point failure and loses functionality if that host unit fails

Engineering Contradiction:
Improvenetwork continuityVSAvoidclock distribution mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system pre-assigns Master Clock Priority Level (MCPL) values to each host unit before any failure occurs. When the primary Master Clock fails, the backup host with the next highest MCPL value automatically takes over without requiring complex real-time negotiation or system reconfiguration, thus maintaining network continuity while keeping the mechanism relatively simple

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent divides the single Master Clock function into multiple potential Master Clock sources (host units with different MCPL values). Each host unit can potentially serve as a Master Clock, with priority determined by its MCPL assignment, creating a segmented redundancy structure that improves reliability

Inventive Principle:
Principle #1Segmentation

2Reliability

If multiple host units are introduced to provide redundancy, then network reliability improves, but it becomes uncertain which host unit provides the Master Clock and how automatic recovery is managed

Engineering Contradiction:
Improvebackup Master Clock availabilityVSAvoidautomatic priority determination
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

Each host unit is assigned a unique local quality attribute (MCPL value) that determines its priority in the clock hierarchy. This local differentiation allows each unit to independently determine its role and the role of others without complex global coordination, enabling automatic priority determination when Master Clock selection is needed

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system implements a feedback mechanism where host units monitor the presence and status of the current Master Clock. When the Master Clock signal is lost or invalid, units feedback this status and automatically transition to Master Clock operation based on their pre-assigned MCPL priorities, enabling seamless automatic recovery

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If host units transmit clock signals on all ports, then all units can potentially synchronize, but conflicts arise when multiple units transmit simultaneously without clear priority arbitration

Engineering Contradiction:
Improveclock signal distribution flexibilityVSAvoidclock signal conflicts
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces asymmetry in the clock distribution system by assigning different MCPL values to different host units. This asymmetric priority structure allows the system to handle symmetric multi-port transmissions without conflict, as each unit knows its relative priority and can arbitrate accordingly when multiple signals are present

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The system changes the parameter of clock signal transmission by embedding MCPL information in the transmitted clock signals. This allows receiving units to not only synchronize to the clock signal but also to identify the priority level of the transmitting unit, enabling intelligent arbitration and conflict prevention

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2371081B1Clock priority chain level systems and methods
Publication Date: 2020.05.20 COMMSCOPE TECHNOLOGIES LLC
  • EP2371081B1 patent drawingFigure 1
  • EP2371081B1 patent drawingFigure 2
  • EP2371081B1 patent drawingFigure 3

AI summary

Clock Priority Chain Level Systems and Methods are provided. In one embodiment, a method for determining clock priority for a multihost unit distributed antenna system is provided. The method comprises identifying which port of a plurality of ports is receiving a reference clock signal having a highest priority Network Chain Level (NCL) value, wherein the highest priority NCL value indicates a master clock priority level (MCPL) of a host unit providing a Master Clock and a chain level value indicating a chain depth; selecting a system clock reference port from the plurality of ports based on the highest priority NCL value; locking a local clock to a reference clock signal received on the selected system clock reference port; calculating an incremented NCL value based on the highest priority NCL value; and transmitting the incremented NCL value over the plurality of ports.