Abstract: A CDMA demodulating apparatus with an improved interference canceling effect when there are a large number of communicators. A reception signal having a frame configuration in which a pilot signal of a known pattern is inserted between information signals is received from a plurality of communicators. Transmission data of each communicator is demodulated, an interference canceler for estimating is provided in a plurality of stages, in each channel of each stage, a variation of transmission path is estimated in each path to achieve data demodulation and estimation of interference replica. The later the stage, the more error of interference signal replica can be reduced, thereby improving the interference canceling effect. An even better effect can be obtained when interference canceling is performed after detecting a reception level of each channel by summation of reception power of each path of each channel, and channel ranking is determined in the order of higher reception level.

Abstract: A CDMA demodulator which can follow fast fading, and reduce interference components from other users in the same cell. A received input spread signal is despread by an orthogonal filer (103). The orthogonal filer provides the input spread signal with successive delays each of an amount of 1/m of the chip interval of a spreading code, multiplies the delayed signals by tap coefficients, and sums up the products, thereby outputting the despread signal. Pilot symbols in the despread signal are compared with known pattern pilot symbols by an absolute phase estimator/phase error compensator (107) to obtain phase fluctuations of the received pilot symbols. The phase fluctuations are interpolated to each information symbol, and each information symbol is phase compensated. The phase compensated information symbols are decided by a decision block (108).