Patent ID: 6937641
Filing Date: 2005-08-30
Classification: H04W

Abstract:
1. In a code-division-multiple-access (CDMA) system employing spread-spectrum modulation comprising a base station (BS) comprising a BS-spread-spectrum transmitter and a BS-spread-spectrum receiver, and a plurality of mobile stations, each mobile station (MS) comprising a MS-spread-spectrum transmitter and a MS-spread-spectrum receiver, a method comprising the steps of: computing an initial power estimate for a first access attempt by one of the mobile stations; transmitting from the MS-spread-spectrum transmitter of the one mobile station a spread-spectrum signal signifying a first attempt to utilize a random access channel, at a power level based on the initial power estimate; receiving one or more access attempt signals relating to the random access channel at the BS-spread-spectrum receiver; measuring the one or more access attempt signals received by the BS-spread-spectrum receiver; computing a closed loop power control symbol specifying an extent that power of the measured one or more received access attempt signals differs from a target power; broadcasting a control message containing the closed loop power control symbol from the BS-spread-spectrum receiver; and if the MS-spread-spectrum receiver of the one mobile station does not detect an acknowledgement responsive to the first access attempt of the one mobile station: