Patent ID: 8417278

Claim:
A wireless communication system of a communication terminal device receiving, by wireless, a signal containing a TPC (Transmitter Power Control) command and a CPICH (Common Pilot Channel) from a plurality of base stations, and sending, by wireless, a signal under a variable transmission power to said base stations, the system comprising: a detection unit detecting timing information of path timing from the received signal; a de-spreading unit de-spreading said received signal based on said detected timing information and a code specified corresponding to said received signal; a combiner unit extracting a symbol data of said CPICH from said de-spread received signal, based on channel estimation on the same time axis with a symbol data of said TPC command for each of said base stations; a judgment unit judging, depending on whether the extracted symbol data of said CPICH falls in a predetermined quadrant of an I-Q (In-phase and Quadrature) plane, whether said correspondent TPC command is valid or invalid; and a transmission power control unit controlling said transmission power corresponding to said TPC command judged as being valid, wherein if said TPC command is judged as being invalid, said quadrant of said I-Q plane is expanded in a step-wise manner.