Method for Distance Estimation in the Presence of Multipath

A Bluetooth network device, comprising:

• a network interface;
• a processing unit;
• and
• a memory device in communication with the processing unit, comprising instructions, which when executed by the processing unit enable the Bluetooth network device to:
• perform a Channel Sounding procedure with a reflector device at a plurality of frequencies to obtain a channel transfer function;
• use the channel transfer function as an input to a MUSIC algorithm to generate a pseudo-spectrum, wherein the pseudo-spectrum comprises a plurality of peaks, each at a respective distance and having a respective amplitude;
• look for a first peak, moving from 0 toward larger distances, in the pseudo-spectrum that has an amplitude greater than a first predetermined threshold;
• look for a second peak, moving from the first peak toward larger distances, in the pseudo-spectrum that has an amplitude greater than the first predetermined threshold;
• create a search region based on the respective distances associated with the first peak and the second peak;
• determine if a peak greater than a second predetermined threshold is present in the search region;
• and
• if so, use the distance associated with the first peak as the distance between the Bluetooth network device and the reflector device.

A network comprising:

• a first Bluetooth network device acting as an initiator device;
• a second Bluetooth network device acting as a reflector device;
• and
• a computational device;
• wherein the first Bluetooth network device performs a Channel Sounding procedure with a reflector device at a plurality of frequencies to obtain a channel transfer function and forwards the channel transfer function to the computational device;
• and wherein the computational device:
• uses the channel transfer function as an input to a MUSIC algorithm to generate a pseudo-spectrum, wherein the pseudo-spectrum comprises a plurality of peaks, each at a respective distance and having a respective amplitude;
• looks for a first peak, moving from 0 toward larger distances, in the pseudo-spectrum that has an amplitude greater than a first predetermined threshold;
• looks for a second peak, moving from the first peak toward larger distances, in the pseudo-spectrum that has an amplitude greater than the first predetermined threshold;
• creates a search region based on the respective distances associated with the first peak and the second peak;
• determines if a peak greater than a second predetermined threshold is present in the search region;
• and
• if so, uses the distance associated with the first peak as the distance between the first Bluetooth network device and the second Bluetooth network device.