Static Delay Compensation in Distributed Antenna Systems

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Solution Overview

Problem

The use of a distributed antenna system (DAS) in telecommunications increases static delay, leading to reduced cell range and potential signal interference and de-synchronization of user devices.

Innovation Solution

A delay unit is introduced to compensate for the roundtrip delay caused by the DAS by adjusting delay compensation signaling between the digital baseband unit and the radio transmitter unit of the base station, leveraging standards like CPRI and OBSAI to manage fiber delays without modifying the base station.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If a distributed antenna system is used to extend wireless coverage, then the cell range is extended, but the static delay increases causing signal interference and de-synchronization

Engineering Contradiction:
Improvecell rangeVSAvoidstatic delay
Core Design Contradiction:
Length of stationary objectVSLoss of time

Solution Approach 1:

The delay unit introduces a pre-calculated delay period to the control information in transmit frames before they are sent to the base station. This preliminary action counteracts the static delay caused by the DAS, ensuring that signals arrive synchronized and preventing interference while maintaining the extended cell range coverage.

Inventive Principle:
Principle #9Preliminary anti-action

2Reliability

If a delay unit is introduced to compensate for roundtrip delay, then signal synchronization is maintained, but system complexity increases

Engineering Contradiction:
Improvesignal synchronizationVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A delay unit is introduced as an intermediary component between the base station and the distributed antenna system. This mediator introduces a controlled delay period to control information in transmit frames, compensating for the static delay caused by the DAS without requiring modifications to the base station itself, thereby maintaining signal synchronization while isolating the complexity to a single modular component.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If control information is delayed in transmit frames, then roundtrip delay is compensated, but data transmission efficiency is reduced

Engineering Contradiction:
Improvedelay compensationVSAvoiddata transmission efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The transmit frame is segmented into control information and data information components. The delay unit applies the delay period specifically to the control information portion of the frame, while data transmission proceeds with minimal disruption. This segmentation allows delay compensation to be applied selectively, maintaining synchronization for control signals while preserving overall data transmission efficiency.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3611851B1Static delay compensation in a telecommunications system
Publication Date: 2021.03.03 COMMSCOPE TECHNOLOGIES LLC
  • EP3611851B1 patent drawingFigure 1
  • EP3611851B1 patent drawingFigure 2
  • EP3611851B1 patent drawingFigure 3

AI summary

A system for use with a base station, the system comprising a distributed antenna system including a head-end unit and one or more remote units communicatively coupled to the head-end unit, the head-end unit configured to transmit signals to the one or more remote units, the signals comprising wireless communication data received from the base station, wherein the one or more remote units are configured to wirelessly transmit the wireless communication data to user devices; and a delay unit configured to communicatively couple to the base station, the delay unit configured to introduce, to the base station, a delay for control information included in a frame processed by the base station, the delay corresponding to an increase in a roundtrip delay between the base station and the user devices caused by the distributed antenna system.