The paper considers a constant modulus cost function with non-canonical constraint

and presents a new blind multiuser detector.First

the capability of the detector to suppress multi-access interfrerence (MAI) is analyzed.The results show that the performance of the detector is not affected by the received power of the demodulated signal.Furthermore

we show that the constant modulus cost function with non-canonical constraint is strictly convex under some conditions.Using the stochastic method

a blind adaptive algorithm can be given

and its convergence is analyzed.The simulation examples demonstrate the results.