Beamforming Feedback for Arrival Time Difference Compensation
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Solution Overview
Problem
In beamforming-based mobile communication systems, differences in signal arrival times due to varying beam transmission paths lead to signal quality degradation and inter-symbol interference, particularly during hybrid beamforming and beam switching, as signals from different paths may have delayed arrival times exceeding the cyclic prefix threshold, affecting the combination and reception of signals.
Innovation Solution
A method and apparatus where a mobile station receives multiple transmit beam signals, generates feedback information indicating the difference in arrival times between effective beam signals, and transmits this information to the base station, allowing the base station to select beams with minimal delay differences for hybrid beamforming and beam switching, thereby preventing signal quality degradation and inter-symbol interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple transmit beam signals are transmitted through different beam paths, then signal coverage and beamforming gain are improved, but signal arrival time differences cause inter-symbol interference and signal quality degradation
Solution Approach 1:
The mobile station performs preliminary measurement of signal arrival times from multiple transmit beams before feedback transmission. By measuring and reporting arrival time differences in advance, the base station can pre-compensate for timing differences through adjustment of transmission timing or cyclic prefix configuration, preventing inter-symbol interference before it occurs
Solution Approach 2:
The mobile station feeds back arrival time difference information to the base station, enabling the base station to adjust beam transmission timing based on actual path differences. This feedback loop allows the system to compensate for timing mismatches caused by different beam paths, resolving the inter-symbol interference problem while maintaining multiple beam transmission benefits
2Area of stationary object
If beam transmission paths are extended to cover larger areas, then signal coverage is improved, but arrival time differences between beams increase causing synchronization issues
Solution Approach 1:
The system dynamically adjusts timing parameters based on measured arrival time differences. By changing transmission timing offsets or cyclic prefix lengths according to the specific beam path characteristics, the system can accommodate larger coverage areas without suffering from excessive arrival time differences that would cause synchronization issues
3Adaptability or versatility
If beam switching is performed to adapt to channel conditions, then system adaptability is improved, but timing misalignment between beams causes signal quality degradation
Solution Approach 1:
The mobile station measures and reports arrival time differences for multiple candidate beams before beam switching occurs. This preliminary timing information allows the base station to pre-adjust timing parameters for the target beam, ensuring smooth beam switching without timing misalignment or signal quality degradation
Data Source
AI summary
A method for operating a mobile station in a mobile communication system. The method includes: receiving a plurality of transmit (Tx) beam signals from a base station; generating indication information for indicating a difference in arrival time between effective Tx beam signals selected from the received Tx beam signals; and transmitting feedback information including the indication information to the base station.