Downlink Positioning Symbols for LOS Detection in Multipath
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Solution Overview
Problem
Existing methods for determining the location of mobile devices in cellular communication systems, such as those used in autonomous vehicle coordination, often lack the accuracy required for precise positioning, especially in dense urban environments, and may require additional communication overhead or complex signal processing.
Innovation Solution
The method involves isolating a line of sight component within a downlink signal by inserting sequences of zero-value samples in the time domain, allowing for precise location determination using angle of arrival algorithms without the need for multiple antennas, and incorporating positioning symbols within the downlink signal to enable accurate positioning without disrupting data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If satellite navigation systems are used for vehicle positioning, then positioning coverage is provided, but positioning accuracy is insufficient in dense urban environments
Solution Approach 1:
The patent extracts the line of sight component from the composite downlink signal by utilizing the time domain isolation created by zero-value sample sequences. This separates the useful LOS signal from harmful multipath components, enabling accurate positioning without being affected by urban environment reflections
Solution Approach 2:
The base station pre-structures the downlink signal by inserting sequences of zero-value samples at specific positions before transmission. This preliminary action creates time domain isolation that prevents multipath components from overlapping with subsequent non-zero samples, ensuring clean LOS component extraction at the receiver
2Measurement precision
If pulse embedded in OFDM symbol is used for distance determination, then positioning function is provided, but positioning accuracy is insufficient for coordinated driving
Solution Approach 1:
The patent employs periodic insertion of zero-value sample sequences within positioning symbols at regular intervals. This periodic structure creates multiple isolated non-zero samples that can be individually processed, improving the reliability and precision of time of arrival measurements compared to single-pulse methods
3Measurement precision
If TDOA algorithm with multiple base stations is used for location determination, then location information is obtained, but communication overhead and system complexity increase
Solution Approach 1:
The patent enables the mobile device to autonomously determine its location by processing the structured downlink signal from a single base station. The zero-value sample sequences provide self-contained timing references that allow the mobile device to perform accurate positioning without requiring complex coordination or additional reference signals from multiple base stations
4Measurement precision
If multiple reference signals are used for positioning, then positioning accuracy is improved, but signal overhead and resource consumption increase
Solution Approach 1:
The patent makes the downlink data channel serve dual functions: normal data transmission and positioning. By structuring the downlink signal with embedded zero-value sample sequences, the same signal carrier provides both communication services and positioning references, eliminating the need for separate positioning reference signals and reducing overall signal overhead
5Measurement precision
If transmission signal is paused and restarted to identify line of sight component, then line of sight component identification is enabled, but data transmission is interrupted
Solution Approach 1:
Instead of pausing transmission, the patent uses periodic zero-value sample sequences embedded within continuous downlink signals. This allows the base station to maintain uninterrupted data transmission while periodically creating time domain isolation windows that enable LOS component identification, thus preserving both transmission continuity and positioning accuracy
Data Source
Figure 1a~1b
Figure 1c~2a
Figure 2b~3
AI summary
The present invention relates to an apparatus, a method and a computer program for a mobile transceiver and for a base station transceiver. The method for the mobile transceiver comprises receiving a downlink signal from a base station transceiver of the mobile communication system via a downlink data channel. The downlink signal comprises one or more positioning symbols. The one or more positioning symbols comprise a first positioning symbol. At least the first positioning symbol is based on a plurality of samples in a time domain to be transmitted by the base station transceiver. The plurality of samples comprises one or more sequences of zero-value samples and one or more non-zero-value samples following the one or more sequences of zero-value samples. The method comprises identifying a line of sight component of at least the first positioning symbol of the downlink signal based on the one or more sequences of zero-value samples. The method comprises determining information related to a location of the mobile transceiver based on the one or more non-zero-value samples received within the line of sight component of the first positioning symbol. In some embodiments, the reception of the downlink signal is calibrated based on a local calibration signal transmitted during a zero-value cyclic prefix of a second positioning symbol transmitted consecutively after the first positioning symbol.