Angle of Departure Determination Using UWB Phase Differences
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Solution Overview
Problem
Existing ultra-wideband (UWB) communication systems require multiple antennas or cooperating receivers to calculate the angle of arrival, which is not feasible in modern RF communication devices with a single antenna, and prior art AoA approaches fail in applications where UWB signals are forbidden from being transmitted by fixed installations but allowed by mobile devices.
Innovation Solution
A method and apparatus for determining the angle of departure (AoD) of an RF signal using a UWB transmitter with two separated transmit antennas and a single receive antenna, calculating phase values and path differences to determine the AoD and Cartesian position, with an AoD circuit for efficient implementation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple receive antennas are used to calculate angle of arrival, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent inverts the traditional angle of arrival approach by having the transmitter perform angle of departure calculations instead of the receiver performing angle of arrival calculations. The mobile device (transmitter) determines the angle by comparing phases of signals received at two fixed anchors, reversing the roles and avoiding the need for multiple receive antennas in mobile devices.
Solution Approach 2:
The patent uses phase information as a copy or representation of the spatial relationship between antennas and receivers. By measuring phase differences in the received signals, the system derives angular information without requiring physical arrays of antennas at the receiver, thus achieving measurement precision through information copying rather than physical replication.
2Measurement precision
If multiple cooperating receivers are deployed to determine angle of arrival, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent reverses the computational burden from the receiver to the transmitter. Instead of requiring multiple receivers to cooperate and perform complex angle of arrival calculations, a single mobile transmitter performs angle of departure calculations by comparing phases received at two fixed anchors, eliminating the need for multiple cooperating receivers.
Solution Approach 2:
The mobile device serves itself by performing the angle determination calculations locally using phase information from two anchors. This self-service approach eliminates the need for complex coordination between multiple receivers and centralized processing, as each mobile device independently determines its angular position.
3Measurement precision
If fixed installations transmit UWB signals for angle of arrival calculation, then measurement precision is improved, but adaptability to regulatory constraints deteriorates
Solution Approach 1:
The patent inverts the transmission role from fixed installations to mobile devices. Since regulations prohibit fixed installations from transmitting UWB but allow mobile devices to transmit, the patent makes the mobile device the active transmitter performing angle of departure calculations, while fixed anchors only receive signals, thus complying with regulatory constraints while maintaining measurement precision.
4Device complexity
If a single receive antenna is used, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent transfers the multi-antenna requirement from the receiver to the transmitter. A single receive antenna at the mobile device is sufficient because the angle determination is performed at the transmitter based on phase comparisons from two fixed anchors, inverting which side needs the antenna array.
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 efficient determination of AoD in UWB communication systems, comparable to prior art techniques but with reduced complexity and cost, suitable for applications where UWB signals are transmitted by mobile devices and received by fixed installations, improving system performance and reducing the need for multiple receivers or anchors.
Implementation Method 1
transmit a channel sounding signal having a frequency, f, greater than 3.1 GHz and less than 10.6 GHz
Implementation Method 2
receive a portion of the transmitted signal via a first receive antenna
Data Source
AI summary
An ultra-wideband (“UWB”) communication system comprising a transmitter having two transmit antennas and a receiver having a single receive antenna. Respective selected portions of the UWB signal are transmitted by the transmitter via each of transmit antennas is received at the receive antenna. By comparing the phases of the received signal portions, the phase difference of departure can be determined. From this phase difference and the known distance, d, between the transmit antennas, the Cartesian (x,y) location of the transmitter relative to the receiver can be directly determined.