Patent ID: 8811508

Claim:
A system, comprising: a first network device configured to transmit a first starting signal; a second network device configured to transmit a second starting signal, wherein at least one of the first network device and the second network device is further configured to change a ratio between at least one of i) respective phases of carriers of the first starting signal and the second starting signal, and ii) respective amplitudes of the carriers of the first starting signal and the second starting signal; and a third network device configured to i) receive the first starting signal and the second starting signal, ii) selectively allow communication with the first network device based on the ratio, iii) ignore communication from the second network device based on the ratio, iv) selectively allow communication with the first network device further based on a frequency of the first starting signal and a frequency of the second starting signal, and v) ignore communication from the second network device further based on the frequency of the first starting signal and the frequency of the second starting signal.