摘要 |
A method and apparatus for reducing co-channel interference in a CDMA radio telephone system wherein a traffic channel signal is transmitted from a first station (e.g., a base station) 100 in the system to a second station in the system (e.g., a mobile station) 200. The traffic channel signal contains information representative of a plurality of CDMA data signals each of which is modulated with a different Walsh code prior to transmission of the traffic channel signal from the first station 100 to the second station 200. A reduced interference signal is formed at the second station 200 by subtracting an interference signal from the traffic channel signal. A decoded signal is formed at the second station 200 by decoding information representative of the reduced interference signal using a decoder 260 that outputs a plurality of metric values. The metric values are then used as inputs to a feedback loop 270, 272, 274, 276, 278, 280 that is used to form the interference signal that is subtracted from the traffic channel signal. In this feedback loop 270, 272, 274, 276, 278, 280, an estimated signal is formed in accordance with the plurality of metric values, a plurality of reconstructed CDMA signals are formed from the estimated signal, each of the reconstructed CDMA signals being modulated in accordance with a different one of the Walsh codes, and the reconstructed CDMA signals are then used to form to the interference signal. |