Self-Synchronizing TDD Antenna System with Cable Loss Compensation

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Solution Overview

Problem

Existing time-division duplex (TDD) antenna systems face challenges in efficiently managing signal loss across transmission line cables, which affects the amplitude of transmit and receive signals, and require active communication with the user communication system for optimal operation.

Innovation Solution

A self-synchronizing TDD antenna communication system with an antenna control circuit that includes a transmission line measurement circuit to determine signal loss and an amplitude adjustment circuit to adjust signal amplitudes based on measured loss, allowing for autonomous operation and efficient communication without requiring active input from the user communication system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If signal amplitude is adjusted based on cable loss measurement, then communication performance is optimized, but device complexity increases due to additional measurement and adjustment circuits

Engineering Contradiction:
Improvecommunication performanceVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The antenna control circuit performs self-calibration by autonomously measuring cable loss through injection of test signals and analyzing returned signals, then automatically adjusts transmit and receive signal amplitudes based on measured loss. This self-service mechanism eliminates the need for external calibration equipment or manual intervention, optimizing communication performance while avoiding additional complex external systems.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system performs cable loss measurement and signal amplitude adjustment during an initialization or calibration phase before actual communication begins. By completing the amplitude optimization in advance, the system ensures optimal communication performance from the start without requiring continuous complex adjustments during operation.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If calibration signal is transmitted through transmission line to antenna and back for loss measurement, then signal loss is accurately determined, but transmission time is consumed during calibration process

Engineering Contradiction:
Improvesignal loss measurementVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The cable loss measurement and amplitude adjustment is performed as a periodic calibration process that occurs at defined intervals or at the beginning of operation. By scheduling this measurement activity periodically rather than continuously, the system achieves accurate signal loss determination while minimizing time consumption during actual communication operations.

Inventive Principle:
Principle #19Periodic action

3Adaptability or versatility

If amplitude adjustment circuit operates in both transmit and receive modes, then signal amplitudes are optimized for bidirectional communication, but switching complexity increases

Engineering Contradiction:
Improvebidirectional communication capabilityVSAvoidswitching complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The amplitude adjustment circuit is designed as a universal component that handles both transmit and receive signal paths with a single unified structure. The same circuitry that measures cable loss during calibration automatically controls amplitude adjustment for both transmission and reception operations, eliminating the need for separate dedicated circuits for each direction and reducing overall switching complexity.

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

Data Source

PatentEP4122124B1Time-division duplex (TDD) antenna system
Publication Date: 2024.06.05 VIASAT INC
  • EP4122124B1 patent drawingFigure 1
  • EP4122124B1 patent drawingFigure 2
  • EP4122124B1 patent drawingFigure 3~4

AI summary

One example includes a self-synchronizing TDD antenna system. The system includes an antenna system to communicate transmit and receive signals and an antenna control circuit coupled to a user communication system. The antenna control circuit includes a transmission line measurement circuit to determine signal loss through a transmission line cable coupled to the antenna system and an amplitude adjustment circuit to adjust amplitude of the transmit and/or receive signals based on the signal loss. A transmit detection circuit monitors signal power of the transmit signal, and a controller switches the amplitude adjustment circuit from a receive mode to a transmit mode in response to the monitored signal power exceeding a predetermined threshold. In the receive mode, the adjustment circuit applies a receive amplitude adjustment to the receive signal, and in the transmit mode the adjustment circuit applies a transmit amplitude adjustment to the transmit signal.