NDP Announcement Frame Training Signal Repetition for Ranging
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Solution Overview
Problem
Current GPS technology is ineffective for providing accurate location information in environments like buildings or tunnels due to the lack of direct satellite visibility, and existing WLAN-based positioning methods face challenges in accurately determining distances and locations within wireless communication systems.
Innovation Solution
A method involving the generation and transmission of Null Data Packet (NDP) Announcement (NDPA) frames, which include a training signal repetition field specifying the number of instances of a training signal, to prepare communication devices for NDPs during ranging measurement procedures, allowing for accurate distance determination and location estimation using NDPs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS technology is used for location determination, then location information can be provided for outdoor navigation, but it becomes ineffective in indoor environments or areas with blocked satellite visibility
Solution Approach 1:
The patent introduces WLAN infrastructure (access points and communication devices) as an intermediary positioning system to replace GPS in environments where satellite signals are blocked. This intermediary system uses wireless signal propagation and time-of-flight measurements to determine positions indoors and in urban canyons, thereby extending location determination capability to previously unserviceable areas.
2Measurement precision
If WLAN-based ranging measurements are performed without standardized NDP formats, then flexibility in measurement procedures is maintained, but measurement precision and reliability deteriorate
Solution Approach 1:
The patent standardizes specific parameters of Null Data Packets (NDPs) and NDP Announcement frames used in ranging measurements, including packet formats, training signal structures, and measurement procedures. By defining standardized parameters for wireless communications, the system achieves consistent and precise distance measurements across different devices and environments, eliminating variability caused by non-standardized implementations.
3Measurement precision
If GPS technology is used for positioning, then direct satellite visibility provides accurate location data, but the system fails in environments like buildings, shopping malls, and tunnels where satellite signals are blocked
Solution Approach 1:
The patent creates a universal positioning system using WLAN infrastructure that can operate across multiple environments - both outdoor areas where GPS works and indoor/urban areas where it fails. The system uses wireless communication devices and access points as positioning infrastructure, enabling location determination through triangulation and time-of-flight measurements regardless of whether GPS satellites are visible, thereby achieving environmental universality.
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 distance measurement and location estimation in challenging environments by standardizing NDP formats and parameters within wireless communication systems, improving positioning accuracy and reliability.
Implementation Method 1
a distance between a first communication and a second communication device is determined by measuring a time of flight of WLAN transmissions between the first communication device and the second communication device
Data Source
AI summary
A first communication device generates a null data packet (NDP) announcement (NDPA) frame to announce a subsequent transmission of one or more NDPs to one or more second communication devices as part of a ranging measurement procedure. The NDPA frame is generated to include a training signal repetition field that specifies a number of instances of a training signal to be included in the one or more NDPs. The first communication device transmits the NDPA frame as part of the ranging measurement procedure. The first communication device generates at least one NDP to include a number of instances of the training signal that equals the number of instances of the training signal indicated by the training signal repetition field in the NDPA, and after transmitting the NDPA frame, transmits the at least one NDP as part of the ranging measurement procedure.