Phase Rotation Antenna Mapping for Frequency Nulling
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Solution Overview
Problem
High correlation between antennas can cause frequency nulling, leading to degradation of signal reception performance in wireless communication systems, particularly in LTE and 5G networks using CDD and VAM technologies.
Innovation Solution
The implementation of band-selective phase switching antenna mapping (BS-PSAM) that dynamically applies phase rotation to each antenna based on channel state information, allowing for frequency-selective diversity and improved signal-to-noise ratio by adjusting phase values per resource block.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If CDD or VAM technology is used to improve spectral efficiency, then frequency utilization is improved, but high correlation between antennas causes frequency nulling and degradation of signal reception performance
Solution Approach 1:
The patent applies different phase rotation values to different resource blocks based on channel state information, making the phase switching behavior frequency-selective. This local differentiation in phase application prevents frequency nulling while maintaining spectral efficiency improvements from CDD/VAM technologies.
Solution Approach 2:
The patent dynamically adjusts phase rotation values based on channel state information feedback from the receiver. This dynamic adaptation allows the system to respond to changing channel conditions and avoid frequency nulling caused by high antenna correlation, thereby maintaining signal reception performance.
2Reliability
If a predetermined delay is applied to OFDM subcarriers for long delay diversity, then diversity gain is achieved, but the approach is limited and cannot adapt to frequency-selective fading
Solution Approach 1:
Instead of applying a uniform predetermined delay across all subcarriers, the patent applies different phase rotation values to different resource blocks based on channel state information. This frequency-selective approach provides diversity gain while adapting to local fading conditions in different frequency regions.
Solution Approach 2:
The patent changes the phase rotation parameter dynamically based on channel state information feedback. This allows the system to adapt phase values to match frequency-selective fading patterns, providing both diversity gain and frequency-selective adaptation capability.
Data Source
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AI summary
Disclosed are a method and a device for differently applying phase rotations for each antenna by dividing a frequency band in order to solve a problem in which reception performance deteriorates in a specific subcarrier when the correlation between antennas is high. According to the present invention, a method by which a transmitter transmits a signal comprises the steps of: estimating the transmission correlation between respective transmission paths; calculating a phase rotation value to be applied to a transmission signal on the basis of the estimated transmission correlation; applying a phase rotation in accordance with the phase rotation value to the transmission signal; and transmitting the transmission signal.