Abstract: The present invention relates to a mobile communication system, particularly relates to a power estimating apparatus of CDMA(code division multiple access) system which performs a power control of a down link or an up link in the CDMA mobile communication system and performs a power control about a CDMA signal by using an extended walsh code. A power estimating method in a CDMA system for distinguishing CDMA channels with a walsh code which is orthogonal to all CDMA channels, comprising the steps of making an extended walsh code having a new format, which is orthogonal to all CDMA channels, by extending a length(code stream) of the walsh code which is used for distinguishing the CDMA channels, according to a walsh function, and estimating a receiving power by correlating a receiving signal with the extended walsh code.

Abstract: An apparatus and method for controlling power in a CDMA system using antenna diversity. The power control apparatus comprises a CDMA base band/IF transmitter for processing an information signal to output K IF signals, K RF modules for converting the K IF signals from the CDMA base band/IF transmitter into K RF signals and transmitting the converted K RF signals through K transmitting antennas, a receiver for receiving a signal from a mobile terminal through a receiving antenna and processing the received signal to output K power control bits and decoded data, and a processor for generating K data channel gains in response to the K power control bits from the receiver and outputting the generated K data channel gains to the CDMA base band/IF transmitter to control transmission powers of the K transmitting antennas.