Coherent Antenna Switching for AoD Positioning
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Solution Overview
Problem
Current Angle of Departure (AoD) estimation techniques in wireless networks face challenges such as calibration difficulties with large antenna arrays, phase shift errors, and increased network traffic, which affect the accuracy and scalability of STA positioning.
Innovation Solution
The proposed method involves the AP transmitting signals in discrete directions with a predefined order, allowing the STA to detect unique tones and estimate AoD, using either simultaneous or sequential transmission from multiple antennas, and employing phase and amplitude sync or relative phase methods to correct for switching-induced errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration is performed for all antennas in a large antenna array, then measurement precision of AoD estimation is improved, but device complexity and time consumption increase significantly
Solution Approach 1:
The patent segments the antenna array into multiple sub-arrays, where each sub-array is calibrated independently rather than calibrating all antennas together. This reduces the complexity of calibration while maintaining sufficient measurement precision for AoD estimation.
Solution Approach 2:
The patent performs calibration only for a subset of antennas (those in the sub-arrays) rather than all antennas in the array. This partial calibration approach reduces time consumption and complexity while providing adequate calibration accuracy for positioning purposes.
2Measurement precision
If signals are transmitted sequentially from multiple antennas, then AoD estimation accuracy is improved, but loss of time increases due to switching operations
Solution Approach 1:
The patent employs periodic transmission patterns where signals are transmitted in structured sequences from different antennas. This periodic approach allows for systematic AoD estimation while minimizing the impact of switching operations through regular, predictable timing intervals.
Solution Approach 2:
The patent performs preliminary synchronization of phase and amplitude before signal transmission begins. This preliminary action ensures that when sequential transmission occurs, the switching-induced time losses are minimized and the AoD estimation accuracy is maintained.
3Manufacturing precision
If phase and amplitude synchronization is performed, then manufacturing precision of signal transmission is improved, but device complexity increases
Solution Approach 1:
The patent implements feedback mechanisms where the system monitors the phase and amplitude of transmitted signals and automatically adjusts them to maintain synchronization. This feedback-based approach achieves high signal transmission precision while managing device complexity through automated control rather than complex mechanical synchronization mechanisms.
Data Source
AI summary
Devices and methods of estimating the AoD of a STA are generally described. The STA receives comparison symbols from a first AP antenna. The comparison symbols are received prior to and after switching of transmitter chains from a first set of antennas to a second set of antennas. AoD symbols are received immediately after the comparison symbols. A phase and amplitude correction is determined based on a phase and amplitude change between the comparison symbols and the second AoD symbol corrected based thereon. The AoD is subsequently estimated based on the symbol measurements.