Beam Direction Selection Using Doppler-Based Angle Estimation
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Solution Overview
Problem
Existing beam selection methods in wireless communications systems face challenges in achieving efficient network coverage and beam forming accuracy, particularly at high frequencies, especially when using time division duplex (TDD) and when transmit and receive antennas are separate, leading to inefficiencies in closed-loop and open-loop approaches.
Innovation Solution
The method involves determining Doppler shift from radio channel estimates to estimate the angle of arrival or departure of radio waves, allowing for efficient beam direction selection, applicable to both TDD and frequency division duplex (FDD), even when transmit and receive antennas have different configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If closed-loop approaches are used for beam selection, then reliable uplink measurements can be obtained, but radio resources are consumed for feedback and reporting delay increases
Solution Approach 1:
The patent performs downlink channel measurements in advance to predict uplink channel conditions, eliminating the need for real-time uplink sounding and feedback. The network node determines beam directions based on pre-acquired downlink channel state information, thus avoiding reporting delay while maintaining measurement accuracy through the reciprocity of TDD channels.
2Loss of time
If open-loop approaches are used for beam selection, then reporting delay is reduced, but beam forming accuracy deteriorates when transmit and receive antennas are separate
Solution Approach 1:
The patent introduces a feedback mechanism where the wireless device reports downlink channel measurement results and beam quality information to the network node. This feedback enables the network to accurately determine uplink beam directions based on downlink measurements, maintaining beam forming accuracy without requiring separate uplink sounding procedures.
3Device complexity
If separate transmit and receive antennas are used, then device complexity is reduced by removing components, but beam forming accuracy cannot be improved with more receive antennas
Solution Approach 1:
The patent replaces the need for complex hardware components (splitters, combiners, duplex filters) with a software-based channel estimation and beam selection algorithm. By using downlink channel measurements and Doppler shift analysis, the system achieves accurate beam forming without requiring separate transmit and receive antenna configurations or additional passive components.
4Productivity
If high frequencies are used to achieve high data rates, then frequency bandwidth availability increases, but network coverage becomes challenging
Solution Approach 1:
The patent implements dynamic beam direction selection that adapts to changing channel conditions, including mobile device movement. By continuously monitoring downlink channel measurements and Doppler shifts, the system dynamically adjusts beam directions to maintain coverage and connectivity at high frequencies, compensating for the reduced propagation range through precise spatial targeting.
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 enables efficient beam direction selection, improving performance and applicability to moving devices, and can be combined with existing beam forming methods, offering a more efficient open-loop solution.
Implementation Method 1
determining a Doppler shift from the radio channel estimates
Data Source
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AI summary
There is provided mechanisms for selecting beam direction for a radio communications device. A method is performed by the radio communications device. The method comprises obtaining radio channel estimates of a radio channel on which radio waves have been transmitted between the radio communications device and another radio communications device at an angle of arrival and departure. The method comprises determining a Doppler shift from the radio channel estimates. The method comprises estimating at least one of the angle of arrival and departure of the radio waves based on the Doppler shift. The method comprises selecting a beam direction for a signal to be transmitted between the radio communications device and this another radio communications device over the radio channel according to the estimated angle of arrival or departure.