Beamformed Timing Measurement for Wireless Positioning Accuracy
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Solution Overview
Problem
Current positioning methods in wireless communications networks, such as those using Received Signal Strength Indicator (RSSI) and Time-of-Arrival (ToA) measurements, face challenges in accuracy due to multipath signals and complex indoor propagation environments, particularly in distinguishing Line-of-Sight (LoS) signals from Non-LoS components.
Innovation Solution
Implementing beamforming technology for timing measurement messages in the Fine Timing Measurement (FTM) procedure, where channel sounding feedback information is used to transmit these messages as beamformed transmissions, enhancing the Signal-to-Noise Ratio (SINR) and improving the detection of LoS signals, thereby increasing the accuracy of Time-of-Arrival estimates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional omnidirectional transmission is used for timing measurement messages, then coverage area is maximized, but positioning accuracy deteriorates due to multipath signals and inability to distinguish LoS from Non-LoS components
Solution Approach 1:
The patent applies beamforming to direct timing measurement messages along a specific path (line-of-sight) between transmitter and receiver, concentrating transmission energy in a focused directional beam rather than omnidirectional spread. This localizes the signal quality improvement to the LoS path, enhancing ToA measurement accuracy by suppressing multipath interference from other directions.
Solution Approach 2:
The patent performs channel sounding before timing measurement to obtain channel state information, which is then used to pre-calculate beamforming weights. This preliminary channel characterization enables the transmitter to anticipate and counteract multipath effects before actual positioning measurements occur, ensuring optimal beamforming configuration is ready when timing messages are sent.
2Measurement precision
If beamforming is applied to timing measurement messages, then positioning accuracy is improved through enhanced LoS signal detection, but device complexity increases due to channel sounding and beamforming weight calculation requirements
Solution Approach 1:
The patent integrates channel sounding and beamforming capabilities into existing WLAN infrastructure (access points and stations), allowing these devices to perform multiple functions: data transmission, channel characterization, beamforming weight calculation, and positioning measurement. This multi-functionality reduces the need for separate dedicated positioning hardware, mitigating the complexity increase.
Solution Approach 2:
The patent implements a feedback mechanism where channel state information obtained from sounding is fed back to the transmitter, enabling dynamic adjustment of beamforming weights. This feedback loop allows the system to adapt to changing channel conditions and optimize positioning accuracy in real-time, making the complexity investment worthwhile through continuous performance improvement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the accuracy of positioning by improving the detection of LoS signals, leading to more precise ToA estimates and consequently more accurate determination of node positions within the wireless communications network.
Implementation Method 1
The first communication node transmits a timing measurement message to the second communication node as a beamformed transmission based on channel sounding feedback information received from the second communication node
Data Source
AI summary
Embodiments herein relate to a method performed by a first communication node (110; 121) for determining the position (of a second communication node (122) in a wireless communications network (100). The first communication node (110; 121) transmits a timing measurement message to the second communication node (122) as a beamformed transmission based on channel sounding feedback information received from the second communication node (122). The first communication node (110; 121) also receives an acknowledgement message from the second communication node (122) for the timing measurement message in the beamformed transmission. Furthermore, the first communication node (110; 121) determines the position of the second communication node (122) at least partly based on a transmission time of the timing measurement message and a reception time of the acknowledgement message. Embodiments of the first communication node (110; 121) are also described. Embodiments herein also relate to a second communication.