UWB Receiver Angle of Arrival Estimation Circuit

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Solution Overview

Problem

Existing ultra-wideband (UWB) communication systems face challenges in accurately determining the angle of arrival of RF signals due to channel-induced noise and inefficiencies in power consumption, particularly in compact RFID tags, where prior art techniques for carrier recovery and timing recovery are suboptimal and power-intensive.

Innovation Solution

A method and apparatus that utilize a wireless receiver with an angle of arrival estimation circuit, separating the RF signal between two antennae by a predetermined distance to calculate the phase difference and determine the angle of arrival, employing a trit-based ADC for improved performance and reduced power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple receivers are used to determine angle of arrival, then measurement precision is improved, but device complexity and power consumption increase

Engineering Contradiction:

Improveangle of arrival determination accuracyVSAvoidnumber of receivers

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple antenna elements into a single receiver unit, integrating the signal processing functions for angle of arrival determination within one receiver. This merging approach maintains the measurement precision benefits of multiple antenna elements while reducing the overall device complexity by eliminating the need for multiple separate receivers

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single receiver is designed to perform multiple functions simultaneously: it processes signals from multiple antenna elements, performs angle of arrival determination, and handles carrier recovery and timing recovery. This multi-functionality allows the system to achieve accurate angle of arrival measurement without requiring multiple specialized receivers

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If traditional carrier recovery and timing recovery techniques are used, then reliability is maintained, but power consumption increases

Engineering Contradiction:

Improvesignal recovery accuracyVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent modifies the operating parameters of the carrier recovery and timing recovery mechanisms to optimize power consumption. By adjusting recovery thresholds, integration periods, and sampling rates, the system maintains reliable signal recovery while significantly reducing the power required for these functions compared to traditional implementations

Inventive Principle:

Principle #35Parameter changes

3Volume of moving object

If compact antenna separation is used in RFID tags, then device size is reduced, but angle of arrival measurement accuracy deteriorates

Engineering Contradiction:

ImproveRFID tag sizeVSAvoidangle of arrival accuracy

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent replaces traditional mechanical or physical separation methods with signal processing techniques to achieve angle of arrival determination. By using digital signal processing algorithms that analyze phase differences and signal characteristics, the system can accurately determine angle of arrival even when antenna elements are closely spaced, thus maintaining measurement precision while enabling compact RFID tag design

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 accurate determination of the angle of arrival with reduced power consumption and hardware costs, comparable to the best prior art techniques, while maintaining performance, by using a trit-based ADC and efficient carrier and timing recovery mechanisms.

Implementation Method 1

calculate the phase difference and determine the angle of arrival

Methodology Applied

Scientific EffectPhase difference:

Data Source

PatentUS10056993B2Angle of arrival using reduced number of receivers

Publication Date: 2018.08.21 DECAWAVE

AI summary

In an ultra-wideband (“UWB”) receiver, a received UWB signal is periodically digitized as a series of ternary samples. During a carrier acquisition mode of operation, the samples are continuously correlated with a predetermined preamble sequence to develop a correlation value. When the value exceeds a predetermined threshold, indicating that the preamble sequence is being received, estimates of the channel impulse response (“CIR”) are developed. When a start-of-frame delimiter (“SFD”) is detected, the best CIR estimate is provided to a channel matched filter (“CMF”). During a data recovery mode of operation, the CMF filters channel-injected noise from the sample stream. Both carrier phase errors and data timing errors are continuously detected and corrected during both the carrier acquisition and data recovery modes of operation. The phase of the carrier can be determined by accumulating the correlator output before it is rotated by the carrier correction. By comparing the carrier phases of two receivers separated by a known distance, d, the angle of incidence, θ, of the signal can be determined. One or more receivers may be adapted to use multiple antennae, thus reducing the total number of receivers relative to the total number of antennae.