Patent ID: 8446888

Claim:
A mobile communication system, comprising: first and second nodes, wherein the first node comprises: a first transmitter and a first receiver, and wherein the second node comprises: a second receiver receiving a ranging signal from the first transmitter, wherein the ranging signal is generated by linear frequency modulation; a frequency synthesizer generating an internal signal by linear frequency modulation in response to a sensing of the reception of the ranging signal; a digital circuit calculating a beat frequency by comparing the ranging signal to the internal signal and evaluating a time lapse from the reception of the ranging signal until the sensing of the reception of the ranging signal by using the beat frequency, wherein the time lapse is part of a response time of the second node; and a second transmitter providing the first receiver with the ranging signal and the response time of the second node, wherein a packet, which is transmitted from the first node to the second node and includes the ranging signal, further includes a selection bit that indicates the packet is set to operate in a ranging mode.