Channel Impulse Response LOS Detection for Accurate Positioning
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Solution Overview
Problem
There are limited methods for accurately detecting whether wireless communication nodes are in line of sight (LOS) with each other, leading to errors in positioning and resource optimization due to non-LOS situations.
Innovation Solution
A multi-step procedure involving channel impulse response measurements and machine learning-based methods to determine LOS, including techniques such as peak strength analysis, time difference, Doppler spread, and 3D modeling, to identify LOS paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If LOS detection is performed using existing methods, then positioning can be attempted, but positioning accuracy deteriorates due to non-LOS situations being undetected
Solution Approach 1:
The system performs LOS detection measurements and evaluations before final positioning computation. The network node receives channel impulse response data, evaluates LOS probability using predefined criteria (such as peak power ratios, delay spreads, or machine learning models), and determines LOS status in advance. This preliminary LOS determination allows the positioning system to select appropriate base stations and measurement methods beforehand, preventing inaccurate positioning computations from proceeding with non-LOS base stations.
Solution Approach 2:
The patent introduces an intermediary LOS evaluation mechanism that acts as a mediator between raw channel measurements and final positioning results. The network node serves as an intermediary that processes channel impulse response data, applies LOS detection algorithms (including machine learning-based methods), and generates LOS probability assessments. This intermediary layer filters and validates base station selections before positioning computation, ensuring that only base stations with confirmed LOS status are used for accurate positioning.
2Measurement precision
If all base stations are used for positioning measurements, then measurement coverage is improved, but error increases due to inclusion of non-LOS base stations
Solution Approach 1:
The network node performs preliminary LOS evaluation on all candidate base stations before the UE performs final positioning measurements. By pre-screening base stations using channel impulse response data and LOS detection algorithms, the system identifies and flags non-LOS base stations in advance. This preliminary filtering reduces the set of candidate base stations, allowing the UE to focus measurements only on validated LOS base stations, thereby maintaining measurement coverage while eliminating erroneous measurements from non-LOS stations.
Solution Approach 2:
The system implements a feedback mechanism where the network node provides LOS status information and base station selection recommendations to the UE. Based on this feedback, the UE adjusts its measurement strategy by prioritizing or excluding specific base stations. The network node continuously monitors channel conditions and updates LOS assessments, providing real-time feedback that guides measurement selection. This feedback loop enables dynamic optimization of measurement sets, ensuring high positioning accuracy while adapting to changing environmental conditions.
3Measurement precision
If LOS detection procedures are implemented, then positioning accuracy improves, but signaling load and complexity increase
Solution Approach 1:
The patent merges LOS detection functionality with existing channel estimation and measurement procedures. The network node utilizes already-acquired channel impulse response data from uplink signals to perform LOS evaluation, combining multiple functions (channel estimation, LOS detection, base station selection) into a unified process. This merging eliminates the need for separate dedicated LOS detection signaling, as the same uplink reference signals used for channel estimation also provide the data needed for LOS determination. The network node integrates LOS assessment results into existing positioning protocol messages, reducing overall signaling overhead while maintaining comprehensive positioning capability.
Data Source
AI summary
A method in a network node and a network is provided to determine line of sight, LOS, base stations for a user equipment (UE) is provided. A request is provided to at least one of the UE and a plurality of base stations to measure and report LOS detection measurements, wherein the plurality of base stations includes base stations of a serving cell of the UE. The LOS detection measurements are received from the at least one of the UE and the plurality of base stations. LOS base stations for the UE are determined based on the LOS detection measurements. An indication of the LOS base stations is transmitted to the UE.