Patent ID: 7123600
Filing Date: 2006-10-17
Classification: H03H,H04B,H04J,H04L,H04N,H04W

Abstract:
1. A method using a code-division-multiple-access (CDMA) system employing spread-spectrum modulation, with the CDMA system having a base station, and a plurality of subscriber units, the method comprising the steps of: transmitting, using spread-spectrum modulation, from said base station, a synchronization channel having a chip-sequence signal used for synchronization by the plurality of subscriber units; receiving at a first subscriber unit of the plurality of subscriber units the synchronization channel; acquiring, at said first subscriber unit, the synchronization channel; synchronizing, at said first subscriber unit, to the synchronization channel; determining, at said first subscriber unit, timing from the synchronization channel; transmitting, using spread-spectrum modulation synchronized to the timing from the synchronization channel, from said first subscriber unit, an access signal, the access signal having a plurality of power levels; detecting, at said base station, the access signal at a particular power level of the plurality of power levels; transmitting, using spread-spectrum modulation, from said base station to said first subscriber unit, responsive to detecting the access signal, an acknowledgment signal; receiving at said first subscriber unit the acknowledgment signal; and transmitting, in response to receiving the acknowledgment signal, using spread-spectrum modulation, from said first subscriber unit to said base station, a spread-spectrum signal with data.