Wireless Device Doppler Shift Separation via Spatial Filtering
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Solution Overview
Problem
In fast time-varying channel environments, such as high-speed railways, the Doppler effect caused by relative movement between the receiving and transmitting ends in wireless communication systems leads to performance issues, including call drops and handover failures, due to the inability to distinguish between carrier frequency offsets and Doppler shifts, which are indistinguishable in existing frequency calibration technologies.
Innovation Solution
An electronic device with a processor configured to perform spatial filtering on received signals from multiple antennas, estimate frequency offsets, and separate Doppler shifts and carrier frequency offsets using spatial filtering parameters, allowing for targeted frequency preprocessing and feedback control to mitigate the Doppler effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If automatic frequency calibration technology is used to measure frequency offset, then the frequency offset parameters are estimated, but the carrier frequency offset and Doppler shift cannot be distinguished from each other
Solution Approach 1:
The patent segments the frequency offset measurement into two distinct components: carrier frequency offset and Doppler shift. By using multiple antennas with different spatial positions, the system separates the measurement of frequency offset caused by oscillator inconsistency from that caused by relative motion, allowing each component to be independently estimated and compensated.
Solution Approach 2:
The patent introduces a spatial dimension by deploying multiple antennas at different positions. This additional spatial dimension enables the system to distinguish between carrier frequency offset and Doppler shift, as the two components manifest differently across the spatial array, allowing for their separate estimation through spatial processing.
2Device complexity
If frequency preprocessing is performed using combined frequency offset parameters, then the processing is simplified, but the Doppler effect cannot be effectively restrained
Solution Approach 1:
The patent segments the frequency preprocessing into two distinct stages: first compensating for carrier frequency offset using estimates from multiple antennas, then separately compensating for Doppler shift. This segmentation ensures that each type of frequency error is addressed with the appropriate compensation method, improving the effectiveness of Doppler suppression while maintaining manageable system complexity.
Solution Approach 2:
The patent implements feedback mechanisms where the estimated carrier frequency offset and Doppler shift parameters are fed back to the transmitting end. This feedback enables the transmitting end to perform targeted frequency preprocessing on subsequent transmission signals, effectively restraining the Doppler effect while maintaining system synchronization.
3Productivity
If Doppler parameter estimation is performed in fast time-varying channel environments, then the Doppler effect can be tracked, but call drops and handover failures occur due to rapid frequency changes
Solution Approach 1:
The patent performs preliminary estimation of carrier frequency offset and Doppler shift parameters using multiple antennas before actual data transmission. By obtaining accurate initial estimates of these parameters through spatial processing, the system prepares compensation values in advance, enabling smoother tracking during fast time-varying conditions and reducing the likelihood of call drops and handover failures.
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 improves throughput performance by accurately tracking Doppler shifts and reducing call drops and handover failures in fast time-varying channel environments, effectively suppressing the Doppler effect and enhancing system robustness.
Implementation Method 1
the Doppler effect caused by a relative movement between a receiving end and a transmitting end
Data Source
AI summary
This disclosure relates to an electronic device for wireless communications, and a wireless communication method. The electronic device comprises one or more processors, wherein each processor is configured to respectively conduct space-domain filtering on received signals of a plurality of antennas, respectively; estimate the frequency shift of corresponding received signals based on the signals, on which space-domain filtering is conducted, of various antennas; estimate, according to the estimated frequency shift and a parameter of the space-domain filtering, a Doppler frequency shift generated by the relative motion between transceiving ends of the received signals and a carrier frequency offset generated by frequency inconsistency of the transceiving ends; and conduct frequency preprocessing on sent signals of the antennas according to the estimated Doppler frequency shift, and/or control to feed back information related to the estimated Doppler frequency shift to a signal sending end.