5G NR Positioning Using Differential AOA and AOD to Filter Multipath
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Solution Overview
Problem
Current location services in wireless communication networks face inaccuracies due to multipath signals, which are not accounted for in existing methods that rely solely on Angle of Arrival (AOA) and Angle of Departure (AOD) for positioning, leading to impaired location accuracy.
Innovation Solution
The solution involves comparing the differential Angle of Arrival (DAOA) of directed beams received by a User Equipment (UE) with the differential Angle of Departure (DAOD) of directed beams transmitted by base stations to identify Line Of Sight (LOS) and multipath beams, using this comparison to improve positioning accuracy by only utilizing measurements from LOS beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AOA and AOD measurements are used for positioning, then location services can be provided, but location accuracy is impaired due to multipath signals
Solution Approach 1:
The patent segments the received signals into LOS and multipath components by comparing differential AOA measurements with differential AOD values. This segmentation allows the system to identify and isolate multipath signals from legitimate LOS signals, enabling selective use of only the accurate LOS measurements for positioning calculations.
Solution Approach 2:
The patent converts the harmful multipath signal interference into a beneficial identification mechanism. By analyzing the characteristics of received signals and comparing them with expected AOD values, the system can identify multipath signals and use this identification to exclude them from positioning calculations, thereby transforming the presence of multipath signals from a purely harmful factor into an opportunity for improved accuracy through selective filtering.
2Measurement precision
If all received beams are used for positioning, then more measurement data is available, but positioning accuracy decreases due to inclusion of multipath beams
Solution Approach 1:
The patent applies segmentation by dividing the set of received beams into two distinct categories: LOS beams and multipath beams. This is achieved through comparison of differential AOA with differential AOD values. The segmentation enables the system to process only the LOS beams for positioning, ensuring high measurement precision while maintaining an adequate quantity of usable beams.
Solution Approach 2:
The patent applies local quality by assigning different qualities or weights to different beams based on their identification as LOS or multipath. LOS beams are designated as high-quality measurements suitable for positioning, while multipath beams are marked as low-quality and excluded. This differential treatment ensures that only measurements meeting the required precision threshold are used.
Data Source
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AI summary
The angle of departure (AOD) of directed beams, e.g., beamformed beams, transmitted by one or more base stations, such as a gNB, and the angle of arrival (AOA) of the directed beams received by a UE may be used to improve positioning accuracy by identifying Line Of Sight (LOS) beams and multi-path beams. The differential AOA (DAOA) of a directed beam pair may compared to the differential AOD (DAOD) of the directed beam pair. Matching DAOA and DAOD may be used as an indication that the directed beams in the beam pair are LOS with the UE, whereas a mis-match indicates one or both of the directed beams are multi-path. The location of the UE may be estimated using the measurement information, e.g., AOA, RTT, RSTD, etc., obtained from LOS directed beams.