Multicarrier Calibration for Array Antenna Timing Synchronization
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Solution Overview
Problem
Existing array antenna calibration technologies face challenges in accurately synchronizing timing across multiple antenna elements, especially when using wideband signals, leading to inefficiencies in calibration due to the influence of delay time differences and synchronization accuracy in digital to analog converters.
Innovation Solution
A calibration device that generates multicarrier calibration signals with assigned and unassigned subcarriers for each antenna element, allowing for simultaneous measurement of amplitude, phase, and delay characteristics, using a multicarrier calibration signal generating unit, injection, extraction, demultiplexing, and calibration processing units to provide data signal calibrating values for precise synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If digital beamforming with different subcarriers assigned to each antenna element is used to simultaneously measure pass-amplitude phase characteristics, then calibration efficiency is improved, but timing synchronization accuracy deteriorates due to delay time differences and D/A converter variations
Solution Approach 1:
The patent segments the calibration process into two distinct phases: a timing calibration phase that measures delay time differences using a timing calibration signal, and a pass-amplitude phase calibration phase that measures amplitude and phase characteristics using a pass calibration signal. This segmentation allows each phase to be optimized independently, resolving the contradiction between calibration efficiency and timing synchronization accuracy.
Solution Approach 2:
The patent introduces a timing calibration signal as an intermediary measurement signal that is specifically designed to measure delay time differences between antenna elements. This intermediary signal enables accurate timing synchronization measurement without interfering with the subsequent pass-amplitude phase calibration process, thereby resolving the contradiction between the two measurement objectives.
2Measurement precision
If adjustment time for delay time differences is increased to improve timing synchronization accuracy, then measurement precision is improved, but calibration time increases
Solution Approach 1:
The patent performs timing calibration as a preliminary action before pass-amplitude phase calibration. By measuring and compensating for delay time differences first using the timing calibration signal, the system establishes accurate timing synchronization upfront, eliminating the need for repeated adjustments during subsequent calibration processes and reducing total calibration time.
Solution Approach 2:
The patent implements continuous calibration by sequentially executing timing calibration followed by pass-amplitude phase calibration without interruption. The timing calibration results are immediately applied to enable accurate subsequent measurements, maintaining continuous useful action throughout the calibration process and minimizing idle time.
Data Source
AI summary
A calibration device of an array antenna is for a transmission means including a plurality of antenna elements and transmission signal processing systems corresponding to the plurality of antenna elements, in which an antenna element transmission signal is calibrated for amplitude and phase differences and a time difference for each of the antenna elements on the basis of a transmission signal calibrating value, the transmission means being for generating a plurality of transmission radio waves applied with amplitude and phase differences and a time difference corresponding to each of the plurality of antenna elements and emitting the transmission radio waves from the respective antenna elements, the calibration device including: a multicarrier calibration signal generating means for generating a plurality of calibration signals based on, in correspondence, a plurality of subcarriers including a first frequency unit of a subcarrier to which a subcarrier symbol is assigned and a second frequency unit not assigned a subcarrier symbol, the plurality of calibration signals being different for each of the plurality of antenna elements; injection means for injecting a plurality of calibration signals generated by the multicarrier calibration signal generating means into the transmission means in one-to-one correspondence to the transmission signal processing systems of the plurality of antenna elements; extraction means for extracting calibration signals processed by the transmission signal processing systems of the plurality of antenna elements; a demultiplexing means for demultiplexing the calibration signals, for the respective antenna elements, extracted by the extraction means into a frequency unit of an assigned subcarrier and a frequency unit not assigned as a subcarrier; and a calibration processing means for obtaining a calibration value for calibrating the amplitude and phase differences and the time difference between the transmission signal processing systems of the plurality of antenna elements using the signals demultiplexed by the demultiplexing means, and providing the transmission signal calibrating value based on the obtained calibration value to the transmission means.