Patent ID: 6515978
Filing Date: 2003-02-04
Classification: H04B,H04J,H04L

Abstract:
A method for use in a base station in a CDMA system which includes K mobiles associated with the base station for providing improved downlink diversity, the method comprising the steps of:modulating Walsh codes with data signals respectively associated with at least a portion of the K mobiles to generate transmit signals for respective transmission on M transmit antennas associated with the base station, wherein M is greater than or equal to two, the data signal associated with a given mobile modulates a different Walsh code in generating each transmit signal, the Walsh codes are selected from a set including 2&boxdr;log2(K)&boxdl; different Walsh codes, and mapping of the data signals onto the Walsh codes for each antenna is determined according to a transmission matrix; and transmitting the respective transmit signals on the M antennas for receipt by at least a portion of the K mobiles, wherein the transmit signals are correlated using M Walsh codes and linearly combined using knowledge of the transmission matrix to obtain data estimates.