Antenna Array Calibration Using On-Board Receiver Feedback

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Solution Overview

Problem

Current antenna array calibration methods in wireless communication face challenges such as phase distortions, interference with normal traffic signals, non-compliance with standards, and complexity in processing requirements, particularly in multi-standard base stations, which affect signal quality and network capacity.

Innovation Solution

A method and apparatus that utilize normal outbound traffic signals for calibration, converting them into parallel baseband signals, and then serializing these signals to provide feedback for impairment correction in separate transmit paths, eliminating the need for special calibration signals and allowing real-time, scalable calibration within the radio unit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If special calibration signals are injected into the transmit path for antenna array calibration, then phase and amplitude distortions can be corrected, but normal outbound traffic signals are interrupted and degraded, negatively impacting network capacity and data throughput

Engineering Contradiction:
Improvephase and amplitude distortion correctionVSAvoidnetwork capacity and data throughput
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent makes the outbound traffic signals serve dual purposes: normal data transmission and calibration reference signals. By using the same traffic signals for both communication and calibration, the system eliminates the need for separate calibration signals, thereby avoiding interruption of normal traffic while still enabling accurate phase and amplitude distortion correction

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

Solution Approach 2:

The system uses its own outbound traffic signals as the reference for calibration, rather than requiring external or dedicated calibration signals. The traffic signals themselves provide the reference information needed to measure and correct transmit path impairments, making the calibration process self-sufficient and independent of separate calibration infrastructure

Inventive Principle:
Principle #25Self-service

2Measurement precision

If special calibration signals are used for calibration in multi-standard base stations, then calibration can be performed, but standards non-compliance and regulatory requirement violations occur

Engineering Contradiction:
Improvecalibration accuracyVSAvoidstandards compliance and regulatory requirement adherence
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent employs a universal calibration approach that works across multiple communication standards by using outbound traffic signals that are already compliant with various standards. This multi-functional calibration method eliminates the need for standard-specific calibration signals, ensuring compliance with multiple standards and regulatory requirements simultaneously

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

3Reliability

If transmission power is increased to compensate for phase distortions, then signal reception and decoding improve, but system load increases, reducing power available for other wireless devices and causing interference

Engineering Contradiction:
Improvesignal reception and decoding qualityVSAvoidsystem power allocation and interference
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies preliminary correction to the transmit path impairments before signal transmission, by adjusting the phase and amplitude of outbound traffic signals based on measured distortions. This pre-correction ensures that signals are transmitted with proper characteristics, eliminating the need for compensatory power increases and avoiding the associated energy loss and interference problems

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3465952B1Method and apparatus for antenna array calibration using on-board receiver
Publication Date: 2020.09.09 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3465952B1 patent drawingFigure 1
  • EP3465952B1 patent drawingFigure 2
  • EP3465952B1 patent drawingFigure 3

AI summary

A method and apparatus for providing feedback for cancellation of signal impairment in a plurality of separate transmit paths of a transmitter are disclosed. According to one aspect, a method includes receiving a plurality of outbound signals transmitted to the antenna array, the received outbound signals having traversed separate transmit paths of the transmitter. The method also includes converting the plurality of received outbound signals to a corresponding plurality of parallel baseband signals. The corresponding plurality of parallel baseband signals are serialized into a serial feedback signal.