RRU Channel Correction via Standing Wave Detecting Channel

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Solution Overview

Problem

Existing LTE systems face performance degradation due to channel delay differences between Remote Radio Units (RRUs) in FDD mode, where existing methods for joint channel correction are not applicable, leading to inconsistent delay consistency and impaired system performance.

Innovation Solution

A base station system that includes a baseband unit and multiple RRUs, where each RRU has a standing wave detecting channel with the same frequency as service transmit channels, allowing for the transmission and reception of correction signals to calculate and apply correction coefficients for channel correction across all service transmit channels, ensuring consistent delay alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If two existing 2T2R RRUs are combined into one 4T4R RRU to improve system performance and reduce costs, then resource utilization improves and costs decrease, but channel delay differences between RRUs cause system performance degradation

Engineering Contradiction:
ImprovecostVSAvoidsystem performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

A dedicated correction signal transmission channel is introduced as an intermediary between RRUs. This separate channel carries correction signals that compensate for delay differences, allowing the combined RRU system to achieve delay consistency without requiring expensive new hardware. The correction channel acts as a mediator that resolves the timing mismatch problem while maintaining cost-effectiveness.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically adjusts timing parameters of correction signals to compensate for delay differences between RRUs. By changing the timing parameters of correction signals based on measured delay differences, the system achieves delay consistency across combined RRUs, resolving the performance degradation issue while maintaining the cost benefits of using existing hardware.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the existing TDD joint channel correction method is applied to FDD systems, then implementation simplicity improves, but the method becomes inapplicable due to frequency mismatch between transmit and receive channels

Engineering Contradiction:
Improveimplementation simplicityVSAvoidsystem applicability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The correction signal transmission channel is designed with multi-functionality to serve both TDD and FDD systems. In FDD mode, it transmits correction signals on forward channels and receives them on reverse channels. In TDD mode, it uses service transmit and receive channels. This universal design allows the same channel structure to adapt to different duplexing modes, resolving the applicability issue while maintaining implementation simplicity.

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

Solution Approach 2:

The system dynamically adapts its operation mode based on the duplexing type. For FDD systems, it uses dedicated correction signal channels with frequency-specific transmission. For TDD systems, it uses service channels with time-division transmission. This dynamic adaptation allows the correction mechanism to work effectively across different system types without requiring completely separate implementation approaches.

Inventive Principle:
Principle #15Dynamics

3Reliability

If a new 4T4R RRU is directly used to replace existing 2T2R RRU to achieve proper channel configuration, then system performance improves, but costs increase and resources are wasted

Engineering Contradiction:
Improvesystem performanceVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of replacing physical RRUs, the system creates a virtual 4T4R configuration by combining two existing 2T2R RRUs. Correction signals are used to copy the timing characteristics of a properly configured 4T4R system, allowing the combined system to emulate the performance of new hardware without the associated costs and resource consumption.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP3043524B1Remote radio frequency unit channel correction method, device and system
Publication Date: 2020.02.12 HUAWEI TECH CO LTD
  • EP3043524B1 patent drawingFigure 1~2
  • EP3043524B1 patent drawingFigure 3
  • EP3043524B1 patent drawingFigure 4~5

AI summary

The present invention relates to the field of communications technologies, and in particular, to a method and apparatus for correcting a channel of a remote radio unit, where a first remote radio unit has a communication connection to a baseband unit, the first remote radio unit includes a service transmit channel and a standing wave detecting channel, and a working frequency of the service transmit channel is the same as a working frequency of the standing wave detecting channel, where the service transmit channel is configured to transmit a correction signal, and the correction signal is sent by the baseband unit to the first remote radio unit; and the service transmit channel is configured to receive a correction signal looped back by an antenna, and send the correction signal looped back by the antenna to the baseband unit, so that the baseband unit calculates a correction coefficient of each service transmit channel according to the correction signal looped back by the antenna, and performs channel correction on each service transmit channel, where the correction signal looped back by the antenna includes at least a correction signal that is transmitted over each service transmit channel of the first remote radio unit and looped back by the antenna.