UWB Message Encoding with Time-Shifted Segments for Low-Power Localization
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Solution Overview
Problem
Existing UWB signal encoding methods face challenges in achieving precise localization with high power consumption and low spectral energy detection, particularly in direct sequence spread spectrum modulation and all-or-nothing modulation.
Innovation Solution
A method for encoding UWB messages using a header encoded by a first pseudo-random code and data segments encoded by a second pseudo-random code, with time-shifting operations to improve autocorrelation peak positioning and reduce energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct sequence spread spectrum modulation is used to improve arrival time estimation accuracy, then measurement precision is improved, but use of energy increases significantly
Solution Approach 1:
The data message is divided into multiple data segments, each modulated with a pseudo-random code. This segmentation allows the receiver to process and correlate individual segments, reducing the computational burden and power consumption compared to processing the entire message at once, while still achieving accurate arrival time estimation through correlation of the segmented data.
Solution Approach 2:
The invention uses a correlation threshold mechanism where the receiver stops processing once the correlation value exceeds the threshold. This partial action approach avoids unnecessary computation beyond what is needed to achieve accurate arrival time estimation, thereby reducing power consumption while maintaining measurement precision.
2Device complexity
If all-or-nothing modulation is used to simplify detection, then device complexity is reduced, but spectral energy detection becomes difficult
Solution Approach 1:
A header encoded by a first pseudo-random code is transmitted before the data segments. This header serves as a preliminary action that enables the receiver to acquire synchronization and detect the presence of the signal before processing the actual data segments, thereby facilitating spectral energy detection without significantly increasing modulation complexity.
Solution Approach 2:
The invention changes the modulation parameter by using different pseudo-random codes for the header and data segments. This parameter change allows the receiver to use correlation-based detection methods that are more effective for spectral energy detection, while keeping the overall modulation scheme relatively simple through the use of standard pseudo-random coding techniques.
3Measurement precision
If sampling frequency is increased to improve arrival time estimate, then measurement precision is improved, but use of energy and hardware costs increase
Solution Approach 1:
The invention replaces the mechanical approach of increasing sampling frequency with a signal processing approach using pseudo-random code modulation and correlation. This substitution allows accurate arrival time estimation to be achieved through correlation processing of lower-rate samples, thereby reducing the power consumption and hardware requirements associated with high-speed sampling while maintaining measurement precision.
4Measurement precision
If header and data segments are encoded with different pseudo-random codes, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The invention uses the same type of pseudo-random code generation mechanism for both the header and data segments, differing only in the specific code sequences used. This universal approach to code generation simplifies the encoding device design, as the same hardware or software module can generate both types of codes, thereby reducing device complexity while still achieving improved arrival time calculation accuracy through the use of distinct code sequences for header and data portions.
Data Source
AI summary
A computer-implemented method for encoding at least one data message intended to be transmitted by a UWB transmitter to a UWB receiver, the method including generation of a header encoded by a first pseudo-random code, the header defining a time reference after which a sequence of data segments is intended to be transmitted; generation of the sequence of data segments, each data segment encoding at least one payload data value by a second pseudo-random code and from the time reference, a position of the data segment in the sequence, an autocorrelation peak of the second pseudorandom code.