US20260280799
2026-09-17
Electricity
H04L5/0048
The patent application describes a method and apparatus for performing channel sounding, a process used to determine the distance between two electronic devices. This technique involves the transmission and reception of a channel sounding signal, which is generated using a sounding sequence combined with an artificial noise symbol. The method includes subtracting the artificial noise from the received signal to reconstruct the original sounding sequence, allowing the calculation of the travel time and subsequently the distance between devices.
Channel sounding techniques are employed to ascertain the distance between wireless communication devices, commonly through calculating the round trip time (RTT) of signals. However, traditional methods using known bit patterns are vulnerable to man-in-the-middle spoofing attacks, where attackers manipulate the timing of the signal to deceive devices into perceiving a shorter distance. While embedding random marker sequences can mitigate such attacks, sophisticated spoofing methods like early commit and late detect (ECLD) can still bypass these defenses.
The proposed solution introduces the use of transparent pseudo-random noise symbols added to the channel sounding signal, which are designed to be easily removed by legitimate devices but challenging for attackers to spoof. This approach enhances security by making the sounding sequence less predictable and thus more resistant to spoofing attacks. The method ensures that only authorized devices can accurately reconstruct the sounding sequence and determine the correct distance.
The first electronic device involved in the process is equipped with a transceiver, processor, and memory. It receives the channel sounding signal, subtracts the artificial noise symbol, and calculates the travel time to determine the distance. Meanwhile, the second device generates the sounding sequence using a Gaussian frequency-shift keying (GFSK) modulator and creates the artificial noise symbol with an orthogonal frequency-division multiplexing (OFDM) modulator. Together, these components enable secure and accurate distance measurement between devices.
This method of channel sounding is particularly beneficial in environments where security and accuracy in distance measurement are critical. By incorporating artificial noise symbols, the technique not only improves resistance against spoofing attacks but also maintains the integrity of the distance estimation process. The described system can be applied in various wireless communication scenarios, enhancing both safety and reliability in device interactions.