Wi-Fi Ranging via Null Data Packet Exchange

The patent extracts and eliminates unnecessary acknowledgment frames (ACK) from the traditional FTM protocol. By removing these redundant acknowledgment steps, the patent reduces the number of interactions between nodes, thereby decreasing the time required for ranging while maintaining the core distance measurement functionality through NDP exchange alone.

The patent implements a streamlined ranging process where the target node directly sends NDP frames without completing the full FTM exchange sequence. This skipping of intermediate acknowledgment steps allows the ranging process to rush through unnecessary protocol steps, achieving faster distance measurement while still obtaining accurate results through the time-of-flight calculation of NDP transmission.

The patent extracts only the essential NDP frames containing timing information from the complex FTM protocol sequence. By taking out and retaining only the necessary NDP exchange steps while discarding redundant acknowledgment frames, the patent maintains the accuracy of distance calculation through time-of-flight measurement while significantly reducing the number of information interactions required.

The patent makes the NDP frame serve multiple functions: it acts as both the data carrier and the acknowledgment signal simultaneously. This multi-functionality eliminates the need for separate acknowledgment frames, reducing interaction complexity while preserving the measurement precision needed for accurate distance calculation through the timing information embedded in the NDP frames.