Multipath Filtering for Wireless RF Signal Angular Location
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Solution Overview
Problem
Conventional Angle of Arrival (AoA) detection techniques for wireless RF signals are less accurate when dealing with significant portions of both direct and multipath signals, leading to incorrect angular location determination of user equipment (UEs), which affects the pointing of downlink beams and data rate in wireless communication systems.
Innovation Solution
The method employs novel filtering using cross correlation matrices of sampled data and shifted sampled data to isolate and cancel out multipath signals, extracting direct path signals for improved angular location accuracy, thereby enhancing the accuracy of AoA detection with reduced computational resources and antenna count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of antennas in the array is increased to improve angular location accuracy, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The patent extracts and removes multipath signals from the received signal mixture through signal processing techniques. By identifying and eliminating the harmful multipath components, the system achieves accurate angular location determination without needing to increase the number of antennas, thus resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
The patent converts the harmful effect of multipath signals into a beneficial process by using the known structure of multipath components (time delays, amplitude attenuations) to design filtering algorithms. The system utilizes cross-correlation matrices and signal modeling to identify multipath signals and cancel them out, transforming what was previously a source of error into a structured problem that can be solved and eliminated
2Measurement precision
If the number of antennas is increased to improve angular location accuracy, then measurement precision improves, but energy consumption increases
Solution Approach 1:
By extracting and removing multipath signals through digital signal processing, the system maintains accurate angular location measurement with a reduced number of antennas. This extraction approach eliminates the need for additional antennas that would consume more energy, while still achieving the desired measurement precision through intelligent signal processing
Solution Approach 2:
The patent changes the approach from increasing hardware resources (number of antennas) to optimizing signal processing parameters (filtering algorithms, cross-correlation matrices, time-delay estimation). This parameter-based solution achieves improved measurement precision without the energy cost of additional antenna elements
3Device complexity
If conventional AoA detection is used without filtering, then device complexity is low, but measurement precision deteriorates due to multipath interference
Solution Approach 1:
The patent applies preliminary filtering actions to the received signals before performing angular location detection. By pre-processing the signals to remove multipath components using cross-correlation matrices and signal modeling, the system ensures that the subsequent AoA detection operates on cleaned data, significantly improving measurement precision without excessive complexity
Solution Approach 2:
The patent introduces an intermediary signal processing stage that acts as a mediator between signal reception and angular location detection. This intermediary filtering process, based on cross-correlation matrices and multipath signal modeling, cleans the signals before they are used for AoA calculation, improving precision while keeping the overall system complexity manageable
Data Source
AI summary
Filtering for sampled data representing uplink wireless RF signals monitored by a pair of antennas is provided to improve accuracy in determining an angular location of an identified UE. An extracted portion of the filtered sampled data is used to improve accuracy in determining an angular location of the identified UE. The extracted portion represents direct path uplink wireless RF signals that have traveled by a line of sight between the pair of antennas and the identified UE. Another portion of the filtered sampled data is cancelled, which represents multiple path (multipath) uplink wireless RF signals that have traveled a longer distance than the direct path signals due to reflection from one or more surfaces on multiple paths between the identified UE and the pair of antennas.