A novel receiver for DS-CDMA downlink

In this paper, the method of detection for the DS-CDMA downlink operating in a frequency selective fading environment is considered. A novel detection method using constant modulus algorithm (CMA) is proposed. With the projection of the equalizer output on the unoccupied spreading codes being zero as a constraint condition, we give an adaptive and a batch linearly constrained CMAs. The proposed method can be used in periodic or aperiodic spreading system and overcomes the shortcoming that the conventional CMA cannot guarantee to converge to a desired user. Simulation results demonstrate that the proposed method offers high detection performance and is capable of combating both channel fading and multiple-access interference.