Patent ID: 6717975
Filing Date: 2004-04-06
Classification: H04B,H04J,H04L,H04W

Abstract:
An improvement to a code-division-multiple-access (CDMA) system employing spread-spectrum modulation, with the CDMA system having a base station (BS) with a BS-spread-spectrum transmitter and a BS-spread-spectrum receiver, and a plurality of remote stations, with each remote station (RS) having an RS-spread-spectrum transmitter and an RS-spread-spectrum receiver, the method comprising the steps of:transmitting from said BS-spread-spectrum transmitter located at said base station, a broadcast common-synchronization channel having a common chip-sequence signal common to the plurality of remote stations, the broadcast common-synchronization channel having a frame-timing signal; receiving at a first RS-spread-spectrum receiver the broadcast common-synchronization channel, and determining frame timing at said first RS-spread-spectrum receiver from the frame-timing signal; transmitting from a first RS-spread-spectrum transmitter an access-burst signal, the access-burst signal having a plurality of segments, with each segment having a preamble followed by a pilot signal, with the plurality of segments having a plurality of power levels, respectively; receiving at said BS spread-spectrum receiver the access-burst signal at a detected-power level; to said first RS-spread-spectrum receiver, responsive to the access-burst signal, an acknowledgment signal; receiving at said first RS-spread-spectrum receiver the acknowledgment signal; and transmitting from said first RS-spread-spectrum transmitter, responsive to the acknowledgment signal, to said BS-spread-spectrum receiver, a spread-spectrum signal having data.