| 摘要 |
A second device (12) comprises: a transmitter configured to transmit a first signal to a first device (11); a receiver configured to receive a second signal that has been transmitted by the first device (11); a demodulator configured to demodulate a second message from the second signal, the second message including an indication of signal strength of the first signal as measured by the first device (11); a signal strength measuring module configured to measure signal strength of the received second signal; and a calculator configured to use the indication of the measured signal strength included in the second message and the signal strength of the second signal as measured by the second device (12) to calculate a measure of the distance between the first and second devices (11, 12). |
