Doppler Frequency Estimation via Beam Scanning Preambles
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Solution Overview
Problem
The rapid increase in mobile traffic due to the spread of smart devices poses a challenge for existing 4G mobile communication systems, which struggle to accommodate the demand, especially in millimeter wave bands where high path loss and Doppler effects cause significant transmission issues, necessitating efficient communication methods to compensate for Doppler shifts and carrier frequency offsets.
Innovation Solution
A method and apparatus for estimating Doppler frequency using a beam scanning process in wireless communication systems, where a receiver performs beam scanning with preambles applied to different beams to estimate Doppler frequency and adjust the oscillator accordingly, enabling efficient compensation of Doppler shifts in the millimeter wave band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If millimeter wave band is used for communication, then system capacity and bandwidth are improved, but transmission loss increases due to high path loss from oxygen and water molecule absorption
Solution Approach 1:
The patent changes the frequency parameter to millimeter wave band (30-300 GHz) to achieve higher system capacity and bandwidth, accepting the trade-off of increased transmission loss. This parameter change enables ultra-multiple communications that exceed microwave communication capacity.
2Productivity
If millimeter wave band is used for communication, then system capacity is improved, but Doppler effect and carrier frequency offset increase due to higher center frequency
Solution Approach 1:
The patent performs preliminary Doppler frequency estimation using beam scanning preambles before main communication. This preliminary action allows the receiver to pre-adjust the oscillator frequency, compensating for Doppler shifts and carrier frequency offsets caused by the high center frequency of millimeter wave communication.
3Measurement precision
If beam scanning process is performed with multiple preambles, then Doppler frequency estimation accuracy is improved, but processing time and complexity increase
Solution Approach 1:
The patent segments the Doppler estimation process into multiple beam scanning operations, each using a specific preamble. By dividing the estimation into discrete beam segments with corresponding preambles, the system achieves accurate per-beam Doppler frequency estimation while maintaining structured processing efficiency.
4Reliability
If oscillator frequency is adjusted for each beam, then communication reliability is improved, but device complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the receiver estimates Doppler frequency for each beam using beam scanning preambles, then feeds back this information to adjust the oscillator frequency accordingly. This feedback loop ensures communication reliability by continuously compensating for Doppler shifts while maintaining manageable complexity through systematic frequency adjustment based on measured parameters.
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
This approach allows for effective compensation of Doppler shifts in the millimeter wave band, improving communication efficiency by accurately estimating and adjusting for Doppler frequency variations across different beams, thereby enhancing communication reliability and capacity in high-frequency wireless systems.
Implementation Method 1
Doppler effect caused by movement in a user equipment, and influence of the carrier frequency offset caused by the oscillator error can be further increased. Therefore, various methods for efficient communication in the millimeter wave band may be required.
Implementation Method 2
the base station can collect the electric power for emitting the millimeter wave in a specific direction and use it as a beam
Data Source
AI summary
Provided is a method for estimating a Doppler frequency in a wireless communication system that operates in a millimeter wave (mmWave) bandwidth. A receiver implements a beam scanning process by using a plurality of preambles corresponding respectively to a plurality of beams to which mutually different beam forming is applied, and estimates a Doppler frequency for each of the plurality of beams. The plurality of preambles may correspond respectively to the beam forming directions of the plurality of beams.