RRH Time-Delay Measurement for Wireless Base Station Synchronization

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Solution Overview

Problem

In wireless communication systems, the synchronization of data transmission between a baseband unit (BBU) and a remote radio head (RRH) is challenged by variable time-delays and jitter due to the use of packet switching networks and open IT architecture, which affects the reliability of audio, video, and data transmission.

Innovation Solution

The implementation of a time-delay measurement unit in the RRH and a synchronization unit in the BBU, which measure and adjust the processing and transmission timing to account for time-delays, ensuring that downlink data is processed and transmitted at the correct time, thereby reducing reception time-delay and jitter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If packet switching network and open IT architecture are used for data transmission between BBU and RRH, then system flexibility and resource pooling are improved, but transmission time-delay becomes variable and transmission jitter occurs

Engineering Contradiction:
Improvesystem flexibilityVSAvoidtransmission time-stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The RRH measures the time-delay in advance and notifies the BBU before actual data transmission occurs. The BBU then adjusts its processing timing based on this pre-measured delay information, ensuring that data is processed and transmitted at the correct time despite the variable delays introduced by packet switching networks.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements a feedback mechanism where the RRH measures actual time-delay, notifies the BBU of this measurement, and the BBU uses this feedback information to adjust its timing for subsequent data processing and transmission. This closed-loop approach compensates for the variable delays inherent in packet switching networks.

Inventive Principle:
Principle #23Feedback

2Productivity

If computing and transmitting resource pool based on open IT architecture is used, then resource utilization efficiency is improved, but processing time-delay becomes variable under operating system influence

Engineering Contradiction:
Improveresource utilization efficiencyVSAvoidprocessing time-delay variability
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The RRH performs preliminary measurement of the time-delay between BBU processing and RRH reception before actual data transmission. This advance measurement allows the system to account for operating system scheduling variations and adjust timing accordingly, maintaining reliable synchronization despite the variable processing delays introduced by resource pooling.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The measured time-delay information is fed back to the BBU, which then adjusts its data processing timing based on this feedback. This mechanism compensates for the variable processing time-delay caused by operating system task scheduling and resource allocation in the pooled computing environment.

Inventive Principle:
Principle #23Feedback

3Reliability

If time-delay measurement and synchronization adjustment are implemented, then reception time-delay and transmission jitter are reduced, but system complexity increases

Engineering Contradiction:
Improvedata transmission reliabilityVSAvoidsynchronization system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The RRH autonomously measures the time-delay between BBU processing and its own reception, and automatically notifies the BBU of this measurement without requiring complex external synchronization equipment. This self-service approach reduces system complexity while maintaining reliable timing adjustment.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system uses a relatively simple feedback mechanism where the RRH measures time-delay, notifies the BBU, and the BBU adjusts its timing based on this information. This straightforward feedback loop achieves reliable synchronization without requiring complex synchronization protocols or additional hardware.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2443884B1Wireless communication system
Publication Date: 2012.10.03 INTERNATIONAL BUSINESS MACHINE CORPORATION
  • EP2443884B1 patent drawingFigure 1
  • EP2443884B1 patent drawingFigure 2
  • EP2443884B1 patent drawingFigure 3

AI summary

The present invention discloses a remote radio head unit, a wireless communication system base station, and a data transmission synchronization method thereof. The wireless communication system base station comprises a remote radio head (RRH) and a baseband unit (BBU) communicably connected through a network, and wherein the BBU is used to process and transmit downlink data to the RRH, said wireless communication system base station further comprises: a time-delay measurement unit in the RRH which is used to measure a time-delay for the downlink data to arrive at the RRH from the BBU; a time-delay notification unit in the RRH for notifying from the RRH to the BBU of time-delay data on the time-delay measured by the time-delay measurement unit; a synchronization unit in the BBU for advancing the starting time for the BBU to process and transmit the downlink data by an amount of time obtained based on the time-delay data notified by the time-delay notification unit. The present invention can reduce or even eliminate the RRH reception time-delay caused by the BBU processing time-delay and data transmission jitter by measuring the time-delay for the downlink data frame to arrive at the RRH of the base station, and correcting the timing pulse for starting the downlink data processing and transmission on the BBU side.