Patent ID: 7787516

Claim:
A wireless communication system for reducing a ranging time, comprising: a plurality of devices transceiving signals for communications, the plurality of devices comprises a transmitting device which transmits a ranging signal, and a receiving device which receives the ranging signal, wherein at least one of the receiving devices comprises: a main synchronization block which determines whether a transceiving signal is a ranging signal, a ranging block which measures a distance between the transmitting device and the receiving device using the ranging signal; and a symbol synchronization block which detects a start point and an end point of a symbol forming the trasceived signal, wherein if the transceiving signal is the ranging signal, the main synchronization block provides the ranging signal to the ranging block without providing the ranging signal to the symbol synchronization block, wherein the transmitting device detects a position of respective devices from the ranging signal, wherein the transmitting device transmits the ranging signal formed of a preamble comprising: at least one chip which has an impulse signal indicative of information; at least one frame which is constructed using a plurality of chips and forms a code relating to a respective device depending on which chip contains the impulse signal; at least one time hopping (TH) code block which is constructed using a plurality of frames; and a direct sequence (DS) code block which forms one bit with the plurality of TH code blocks and is constructed using a plurality of bits, and wherein the main synchronization block group comprises: a chip synchronization block which determines in which chip the impulse signal resides; a frame synchronization block which determines in which chip the impulse signal resides within the frame; and a code synchronization block which acquires a TH code with respect to each frame in the TH code block and determines whether the acquired TH code matches a TH code generated at the transmitting device.