Wireless communication system and its transmission power control method

Abstract

An uplink channel transmission power control method is provided for a CDMA mobile communication system performing one way communication. A base station measures the received level of data transmitted from each mobile terminal at each channel, and generates a transmission power control signal of each uplink traffic channel. The generated transmission power control signals are multiplexed, and the multiplexed common transmission power control signal is transmitted to all mobile terminals by using the common channel shared by the mobile terminals. Each mobile terminal derives the transmission power control signal of the uplink traffic channel used by the terminal, from the received common transmission power control signal, and controls the transmission power of a data packet.

1 - 26 . (canceled) 
     
     
         27 . A transmission power control method in a spread spectrum communication system which performs communications between a base station and a plurality of mobile terminals by using a code division multiple access system, comprising the steps of:
 transmitting, by the base station, transmission power control signals by using a traffic channel destined for each of communicating mobile terminals and a control channel in common to the plurality of mobile terminals; and   deriving, by a mobile terminal, a transmission power control signal corresponding to a channel currently used by the communicating mobile terminal, from among the transmission power control signals which are sent from the communicating base station to the mobile terminal, to perform transmission power control of a transmission signal according to the transmission power control signal thus derived.   
     
     
         28 . A base station for performing communications between the base station and a plurality of mobile terminals by using a code division multiple access system, comprising:
 a unit that transmits transmission power control signals corresponding to a plurality of channels by using a traffic channel destined for each of communicating mobile terminals; and   another unit that multiplexes the transmission power control signals corresponding to the plurality of channels, to transmit the transmission power control signals thus multiplexed by using a control channel in common to the plurality of mobile terminals.   
     
     
         29 . A mobile terminal for communicating with a base station by using a code division multiple access system, comprising:
 a first channel demodulator that receives a data signal and a transmission power control signal contained in traffic channel sent from a base station that is communicating with the mobile terminal;   a second channel demodulator that receives a transmission power signal contained in a control channel sent from the base station that is communicating with the mobile terminal′   a unit that derives the transmission power control signal corresponding to the channel that the mobile terminal is using; and   a unit that performs transmission power control of a transmission signal according to the transmission power control signal thus derived.