Mobile Terminal Test Device Doppler Frequency Variation
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Solution Overview
Problem
Existing methods for testing mobile terminals' frequency variation due to the Doppler effect during high-speed movement are inefficient, as they do not allow for real-time and long-term measurement of uplink signal frequency variation, due to limited memory capacity and the need for storing waveform data.
Innovation Solution
A mobile terminal test device and method that includes a transmitting/receiving unit, a test processing unit, frequency variation giving means, detection means, and correction means to simulate and detect frequency variations in real-time, eliminating the need for storing waveform data by continuously correcting and displaying frequency variations of the uplink signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If waveform data is stored for later analysis to calculate frequency variation, then frequency variation can be measured, but real-time measurement is not possible and measurement duration is limited by memory capacity
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing frequency variation data as the mobile terminal moves through different positions, rather than storing raw waveform data and analyzing it later. The test device pre-processes the data during the test, converting waveform data to frequency variation data in real-time and storing only the essential frequency variation information, which enables both real-time measurement and extended measurement duration.
2Measurement precision
If waveform data is stored for later analysis to calculate frequency variation, then frequency variation can be measured, but measurement duration is limited by memory capacity
Solution Approach 1:
The patent applies the extraction principle by extracting only the essential frequency variation data from the raw waveform data in real-time during the test. Instead of storing entire waveform data which consumes large memory capacity, the system extracts and stores only the frequency variation parameters, significantly reducing storage requirements and enabling long-duration measurements without being constrained by memory capacity.
3Reliability
If the same frequency variation as Doppler effect is transmitted to a fixed mobile terminal, then frequency follow-up capability can be tested, but the test process becomes complex requiring waveform storage and analysis
Solution Approach 1:
The patent replaces the mechanical process of storing and analyzing waveform data with an automated signal processing system. The test device automatically generates frequency variations simulating Doppler effects, transmits them to the mobile terminal, and automatically measures the terminal's frequency follow-up capability by comparing transmitted and received frequency data, eliminating the need for manual waveform storage and analysis while maintaining test reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables real-time and long-term measurement of frequency variations during high-speed tests, improving test efficiency by detecting and displaying frequency characteristics without the need for storing and analyzing waveform data, thus accurately assessing mobile terminal performance.
Implementation Method 1
frequency variation giving means (25a) for giving a predetermined frequency variation when a situation in which the mobile terminal that moves together with a high-speed moving body approaches or is separated from the base station is simulated to the downlink signal
Implementation Method 2
a receiving unit (24) that receives an uplink signal output from the mobile terminal which has received the downlink signal and converts the uplink signal into a baseband signal
Implementation Method 3
frequency correction means (25c) for correcting a frequency of a local signal which is used by the receiving unit to obtain the baseband signal, on the basis of the frequency variation detected by the frequency variation detection means
Data Source
AI summary
A frequency variation provider gives a predetermined frequency variation when a situation in which a mobile terminal approaches or is separated from a base station is simulated to a downlink (DL) signal which is transmitted to a mobile terminal by a transmitting unit. A receiving unit receives an uplink (UL) signal output from the mobile terminal which has received the DL signal and converts the UL signal into a baseband signal. A frequency variation detector detects a frequency variation of the UL signal from the baseband signal. A frequency corrector corrects the frequency of a local signal which is used by the receiving unit to obtain the baseband signal, on the basis of the detected frequency variation. A variation characteristic display displays the characteristics of the frequency variation of the UL signal transmitted from the mobile terminal on a display unit.