Uplink Frequency Compensation Using BS Feedback for Doppler Error
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Solution Overview
Problem
In point-to-multipoint wireless communication systems, conventional frequency compensation methods fail to effectively address the Doppler Effect-induced frequency errors when user equipment moves at high velocities, leading to decoding failures due to rapid frequency changes.
Innovation Solution
A frequency compensation device and method for user equipment, comprising a receiving module with an offset detection unit to calculate frequency differences and a transmitting module that adjusts the transmitting frequency based on obtained base station parameters to compensate for the Doppler Effect, ensuring accurate signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE proactively corrects the transmitting frequency according to the receiving frequency error, then the frequency compensation is performed, but the Doppler Effect error doubles making the error greater
Solution Approach 1:
Instead of the UE correcting its transmitting frequency based on receiving frequency error (conventional approach), the invention inverts the approach by having the BS measure the uplink frequency error and notify the UE of the correction value. This reversal eliminates the doubling of Doppler Effect error because the BS's measurement is used directly without being compounded by the UE's active correction mechanism.
Solution Approach 2:
The BS acts as an intermediary that measures the frequency error and provides correction information to the UE. This intermediary role allows the system to obtain accurate frequency error measurements at the BS and communicate the necessary correction to the UE, avoiding the error doubling problem inherent in direct UE-based correction.
2Reliability
If the BS proactively notifies the UE to revise the transmitting frequency, then frequency correction is achieved, but the UE needs long reaction time while the Doppler Effect impact period is short
Solution Approach 1:
The BS performs preliminary measurement of the uplink frequency error and prepares the correction value in advance. By having the BS continuously monitor and pre-calculate the necessary frequency correction before the UE needs to adjust, the system reduces the reaction time required while maintaining effective compensation for the short-duration Doppler Effect impact.
Solution Approach 2:
The system implements a feedback mechanism where the BS measures the actual uplink frequency error and notifies the UE of the correction value. This closed-loop feedback allows for real-time frequency error compensation with minimal delay, as the BS continuously monitors and provides updated correction information to the UE.
3Reliability
If the UE increases the transmitting frequency to compensate for Doppler Effect, then the receiving frequency increases due to Doppler Effect making the error greater
Solution Approach 1:
The BS performs self-service by measuring its own received uplink frequency error directly at the point of reception. This self-measurement approach ensures accurate detection of the actual frequency error including Doppler Effect, allowing the BS to provide precise correction values to the UE without the error compounding issues that occur when the UE attempts self-correction.
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
The solution enables real-time frequency compensation, minimizing decoding failures and maintaining reliable wireless communication even during high-speed user equipment movement by accurately adjusting the transmitting frequency to counteract Doppler-induced errors.
Implementation Method 1
a dramatic frequency difference is generated between a sending frequency and a receiving frequency of the same signal due to a Doppler Effect
Data Source
AI summary
A frequency compensation device, applicable to a user equipment (UE) communicating with a first base station (BS), includes a receiving module and a transmitting module. The receiving module has an offset detection unit for performing following steps. A first signal from the first BS at a first receiving frequency is received. A first transmitting frequency where the first BS transmits the at least one first signal is read. A difference between the first transmitting frequency and the first receiving frequency is calculated and used as a frequency difference. The transmitting module is for performing following steps. A BS parameter corresponding to the first BS is obtained. A frequency compensation value according to the BS parameter is calculated. A second transmitting frequency according to the frequency compensation value corresponding to the first BS is compensated. A second signal to the first BS at the compensated second transmitting frequency is sent.