UWB PDoA Estimation Using Fragmented Ternary Sequences
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing UWB communication systems face challenges in accurately determining phase difference of arrival (PDoA) due to sensitivity to carrier and clock frequency errors, especially in multi-millisecond frame formats, which are more susceptible to these errors.
Innovation Solution
A method and system for determining PDoA using non-coherent UWB receivers that accumulate channel impulse response estimates based on absolute values of individual frame fragments, reducing sensitivity to CFO and clock offset by computing phasor values and phase differences across multiple fragments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MMS frame format is used to increase ranging range, then energy per ms increases and link budget improves, but sensitivity to carrier and clock frequency errors increases
Solution Approach 1:
The patent divides the sounding sequence into multiple frame fragments transmitted over several milliseconds. Each fragment is processed independently to compute individual CIREs, which are then accumulated. This segmentation allows the system to benefit from extended transmission time and increased energy while processing each fragment with sufficient timing resolution to maintain PDoA accuracy despite frequency offsets.
Solution Approach 2:
The patent uses multiple copies of the same sounding sequence transmitted in different frame fragments. By receiving multiple copies and computing CIREs for each fragment, the system can accumulate the results to improve ranging range and link budget while using the redundant information to mitigate the effects of frequency errors through consistent phase difference measurement across copies.
2Measurement precision
If coherent receivers are used to maintain PDoA estimation accuracy, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent employs non-coherent receivers that do not require complex phase tracking and frequency offset compensation mechanisms. Instead of maintaining coherent phase information throughout the extended MMS transmission, the system computes PDoA independently for each frame fragment and accumulates the results. This approach uses simpler, less expensive receiver architecture while still achieving accurate PDoA estimation through the accumulation of multiple independent measurements.
Data Source
AI summary
A method for determining an angle from an ultra-wideband (UWB) device, including the following operations. A first frame fragment is received from the UWB device containing a first ternary sequence of chips by a first antenna, and another first frame fragment is received from the UWB device containing the first ternary sequence of chips by a second antenna. A first channel impulse response estimate (CIRE) is determined corresponding to the first frame fragment and another first CIRE is determined corresponding to the other first frame fragment. A phasor value is determined based on the first CIRE and the other first CIRE. A phase difference of arrival (PDoA) from the UWB device is determined based on the phasor value.