Huawei Technologies Co., Limited

Limei Wei

Guolin Wang

Yu Jin

A method for double weighting parallel interference cancellation in CDMA mobile communication system, integrates ideas of both partial weighting method and weighting method based on Bayes rule. When making a decision on each symbol of the user, calculating reliability coefficient of a decision result on the symbol of the user according to the weighting algorithm based on Bayes rule; weighting regenerated signal of the symbol of the user with the reliability coefficient. During process of MAI estimating and removing, obtaining the MAI on the expected user from weighted regenerated signal of other users in chip level; and then setting a weight value, weighting the MAI with the weight value. Finally, removing weighted MAI from received signal, which means partially removing MAI produced by other users on the expected user. At the same time, the present invention also discloses a double weighting PIC method with simplified algorithm, which transfers weighting in chip level to weighting in symbol level, replacing a Hyperbolic tangent decision with a piecewise linear decision method or a look-up table method.

Method of double weighting parallel interference cancellation

In a method for parallel interference cancellation (PIC) in a mobile communication system, every user signal is processed through multiple stages of PIC to remove multiple address interference (MAI) partly. In any middle stage and final stage, multipath de-spread is made for output signal of last stage to obtain a multipath de-spread result of this stage. The multipath de-spread result of this stage and that of the last stage of a user are combined to obtain a combined multipath de-spread result, which is sent to next stage when it is in a middle stage. Channel estimation and multipath combination are made based on the combined multipath de-spread result to obtain an output of the user. A PIC device is provided for the method. The method and the PIC device may raise SNR of the de-spread result of each user.

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Limei Wei