Patent ID: 6507601
Filing Date: 2003-01-14
Classification: H04B,H04L,H04W

Abstract:
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 an MS-spread-spectrum transmitter and an MS-spread-spectrum receiver, a method comprising the steps of:transmitting from the MS-spread-spectrum transmitter of one of the mobile stations an access preamble signal signifying an attempt to access an intended one of a plurality of uplink transmission channels; receiving the access preamble via the BS-spread-spectrum receiver, at the base station; responsive to receipt of the access preamble signal, transmitting an acknowledgment signal corresponding to the access preamble signal from the BS-spread-spectrum transmitter of the base station; receiving the acknowledgment signal at the MS-spread-spectrum receiver of the one mobile station; transmitting from the MS-spread-spectrum transmitter of the one mobile station a spread-spectrum signal comprising at least one of data and control information, over the one intended uplink transmission channel, responsive to the receipt of the acknowledgment signal; transmitting a predetermined sequence from the BS-spread-spectrum transmitter, over a downlink channel corresponding to the one intended uplink transmission channel; and continuing the transmitting from the MS-spread-spectrum transmitter of the one mobile station over the one intended uplink transmission channel, only upon successful reception of the predetermined sequence over the downlink channel corresponding to the one intended uplink transmission channel at the MS-spread-spectrum receiver of the one mobile station.