TPC (Transmit power control) is one of the key techniques to maximize the capacity of CDMA(Code Division Multiple Access) system.Highly precise measurement of inner-loop SIR (instantaneous signal-to-average interference plus background noise ratio) is the foundation of highly precise fast closed-loop TPC in WCDMA (Wideband Code Division Multiple Access) system which is selected as one system for IMT-2000 (International Mobile Telecommunications-2000).This paper proposes a new measurement method of inner-loop SIR based on 3GPP (the third Generation Partnership Project) protocols

which is prone to modularization

and compares it with another method brought forward by Shunsuke in principle and performance.It has been proved that the new measurement method has the better performance by means of computer simulation.The performance of fast closed-loop TPC based on producing equal QoS (Quality of Service) for all users is also given.