Null Data Packet Announcement Range Estimation
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Solution Overview
Problem
Current wireless local area network (WLAN) technologies face inefficiencies in range estimation due to limitations in existing measurement protocols, such as sequential measurements for multiple stations and lack of utilization of MIMO antennas, which restricts bandwidth usage and response times.
Innovation Solution
Implementing a null data packet announcement (NDPA) based measurement protocol that allows simultaneous packet exchanges with multiple stations using IEEE 802.11ax uplink MU-MIMO, enabling more efficient range estimation by determining time of arrival and departure for round trip time calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sequential measurements are used for multiple stations, then measurement protocol simplicity is maintained, but productivity and response time deteriorate
Solution Approach 1:
The patent combines multiple sequential range estimation measurements into a single simultaneous measurement operation using MU-MIMO technology. The access point transmits reference signals to multiple stations at the same time through different spatial streams, and receives responses from multiple stations simultaneously, thereby merging multiple measurement operations into one and significantly improving productivity.
Solution Approach 2:
The patent introduces a new dimension for measurement by utilizing MIMO spatial dimension. Instead of measuring stations sequentially in time domain, the system measures multiple stations simultaneously by exploiting the spatial dimension provided by multiple transmit and receive antennas, allowing parallel range estimation across multiple spatial channels.
2Measurement precision
If MIMO antennas are not utilized, then device complexity is reduced, but bandwidth utilization and measurement precision deteriorate
Solution Approach 1:
The patent exploits the spatial dimension provided by MIMO antenna systems to improve measurement precision. By transmitting reference signals through multiple spatial streams and receiving responses from multiple antennas, the system obtains richer channel information and more accurate time of arrival measurements, thereby enhancing range estimation accuracy.
Solution Approach 2:
The MIMO antenna system serves multiple functions: it enables simultaneous communication with multiple stations, provides spatial diversity for improved signal reliability, and offers multiple spatial streams for parallel range measurements. This multi-functionality allows the same hardware infrastructure to support both communication and precise positioning without requiring additional dedicated components.
3Productivity
If traditional measurement protocols are used, then compatibility with legacy devices is maintained, but bandwidth utilization and response time deteriorate
Solution Approach 1:
The patent designs the measurement protocol to serve both legacy and modern devices. The access point can perform traditional sequential measurements when communicating with legacy stations while simultaneously performing MU-MIMO based simultaneous measurements with modern 802.11ax stations. This universal approach allows the system to maximize bandwidth utilization with capable devices while maintaining backward compatibility.
Solution Approach 2:
The patent segments the measurement process into different operational modes that can be selected based on device capabilities. The system can choose between traditional sequential measurement mode for legacy devices and simultaneous MU-MIMO measurement mode for 802.11ax devices, allowing optimized bandwidth utilization for each device type while maintaining overall system compatibility.
Data Source
AI summary
Methods, apparatuses, and computer-readable medium are described for doing fine timing measurements for one or more stations. A trigger frame is encoded for stations. Uplink null data packets are received. A time of arrival for the UP NDP and a time of departure for a downlink null data packet are determined. The time of arrival and time of departure are encoded into a data packet, such as a downlink null data packet announcement. A wireless device is configured to transmit the data packet to a station.