Reducing ToF Calculation Complexity in Multipath Wireless Signals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current solutions for indoor navigation struggle to accurately calculate the time-of-flight (ToF) of wireless signals in multipath environments due to the complexity of distinguishing the line-of-sight (LoS) signal from multiple replicas, limiting their effectiveness and scalability.
Innovation Solution
The implementation of a maximum likelihood solution with reduced complexity, utilizing techniques such as singular value decomposition (SVD) and derivative analysis to simplify the calculation of ToF, allowing for efficient identification of the LoS signal and subsequent location determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional maximum likelihood solution is used to identify LoS signal in multipath environment, then measurement precision of ToF is improved, but device complexity increases significantly
Solution Approach 1:
The patent segments the complex maximum likelihood problem into distinct phases: signal reception, correlation processing, peak detection, and ToF calculation. By dividing the computational task into manageable segments with clear boundaries, the system maintains measurement precision while reducing overall calculation complexity through modular processing.
Solution Approach 2:
The patent applies preliminary action by performing correlation processing between received signals and expected signal templates before conducting the full maximum likelihood analysis. This preliminary step pre-processes the signal data, creating a simplified representation that reduces the computational burden of subsequent ToF calculation while preserving the accuracy needed for precise measurement.
2Measurement precision
If traditional ToF calculation methods are used, then location determination accuracy is improved, but productivity decreases due to high computational load
Solution Approach 1:
The patent substitutes complex mechanical computation with optimized signal processing techniques. By replacing traditional iterative maximum likelihood algorithms with correlation-based methods and efficient peak detection algorithms, the system achieves the same location determination accuracy with significantly reduced computational load, thereby improving processing efficiency and productivity.
Solution Approach 2:
The patent changes the computational parameters by transforming the ToF calculation from a direct maximum likelihood optimization problem into a correlation-based parameter estimation problem. This parameter transformation allows the use of more efficient algorithms that maintain accuracy while reducing the number of computational operations required, thus improving productivity.
3Reliability
If full maximum likelihood analysis is performed on all received signals, then reliability of LoS identification is improved, but loss of time increases due to extensive processing
Solution Approach 1:
The patent extracts only the essential features needed for reliable LoS identification from the complete signal set. By taking out and focusing on correlation peaks and their temporal characteristics rather than performing full maximum likelihood analysis on all signal parameters, the system maintains high reliability in LoS identification while significantly reducing processing time.
Solution Approach 2:
The patent implements skipping by using rapid correlation-based methods to quickly identify candidate LoS signals before applying more rigorous verification. This allows the system to rush through the initial screening phase efficiently, maintaining reliability by verifying candidates with targeted analysis, rather than applying full maximum likelihood analysis uniformly to all signals which would waste time on obvious non-LoS signals.
Data Source
AI summary
Examples are disclosed for determining a time-of-flight (ToF) of a wireless signal in a multipath wireless environment. In some examples a method for determining a time-of-flight (ToF) of a wireless signal in a multipath wireless environment may comprise receiving two or more wireless signals over a wireless communication channel from wireless device, determining a maximum likelihood solution for identifying a line-of-sight (LoS) signal of the two or more wireless signals, reducing the complexity of the maximum likelihood solution, determining a time that maximizes the reduced complexity maximum likelihood solution, and determining the ToF of the LoS signal based on the reduced complexity maximum likelihood solution and the determined time. Other examples are described and claimed.