Two-Antenna Angle Estimation Using Multi-Channel Sounding
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Solution Overview
Problem
Current narrow-band system (NBS) localization technologies rely on multiple distributed anchors, which are high-cost and may not be feasible in scenarios with strict device dimension constraints, and conventional Bluetooth-LE direction finding anchors require large antenna arrays that are impractical in constrained environments.
Innovation Solution
A method for angle estimation using channel sounding technology with a communication device equipped with two aligned antennas, performing signal exchanges through multiple channels, storing I/Q samples, estimating channel frequency responses, and determining weights to calculate the angle of arrival based on phase and amplitude differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple distributed anchors are used for localization, then positioning accuracy is improved, but system cost and complexity increase
Solution Approach 1:
The system segments the localization function by separating the anchor device (with two antennas) from the target device, allowing positioning to be achieved through signal exchange and channel estimation rather than requiring multiple physical anchors. The two antennas at the anchor are segmented to provide spatial diversity for angle estimation.
Solution Approach 2:
The patent introduces channel frequency response estimation as an intermediary mechanism to extract spatial information. By estimating the channel response between antennas and using I/Q samples, the system can determine angle of arrival without requiring multiple physical anchors, thus reducing system complexity while maintaining positioning accuracy.
2Measurement precision
If large antenna arrays are used for direction finding, then angle estimation resolution is improved, but device dimension constraints are violated
Solution Approach 1:
The patent changes the operational parameters by using frequency-domain analysis (channel frequency response estimation across multiple frequencies) instead of spatial-domain approaches. By exploiting the phase and amplitude differences in the frequency domain, the system achieves high angle estimation resolution with only two antennas, avoiding the need for large physical antenna arrays.
Solution Approach 2:
The system transitions from spatial dimension (large antenna arrays) to frequency dimension (multi-frequency channel sounding). By performing channel estimation across multiple frequency channels and analyzing the phase progression, the patent achieves angular resolution without increasing physical footprint, effectively using another dimension (frequency) to solve the spatial resolution problem.
3Device complexity
If two antennas are used for angle estimation, then hardware complexity is reduced, but measurement precision may be compromised
Solution Approach 1:
The system performs preliminary channel sounding and I/Q sample collection across multiple frequency channels before angle estimation. By pre-processing the signal to extract channel frequency responses and compensate for phase offsets, the system maximizes the information available from just two antennas, thereby maintaining measurement precision despite the reduced hardware configuration.
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
Enables accurate angle estimation with reduced hardware complexity and cost, suitable for devices with limited space, using narrow-band systems like Bluetooth LE and IEEE 802.15.4, enhancing spatial resolution and localization accuracy.
Implementation Method 1
determining weights for the first antenna and the second antenna respectively by using the channel frequency responses h1 and h2
Implementation Method 2
determining, based on the weight w1(1) and the other weight w2(1), the angle of arrival, relative to the normal, of the signal direct from the second communication device
Data Source
AI summary
A method for determining an angle of arrival at a first communication device having a first antenna and a second antenna aligned along a direction and defining a normal thereto. The method comprises performing a respective signal exchange through each of a plurality of channels between the first communication device and a second communication device, storing a first plurality of in-phase and quadrature (I/Q) samples; estimating channel frequency responses for the first antenna and the second antenna respectively; measuring a respective distance; creating respective standard channel frequency response components corresponding to the respective distances; for each propagation path, selecting a first respective weight and a second respective weight; selecting a weight w1(1) and an other weight w2(1);determining, based on the weight w1(1) and the other weight w2(1), the angle of arrival, relative to the normal, of signals direct from the second communication device.