Base station apparatus, user terminal, communication system and communication control method

Abstract

The present invention is designed to provide a base station apparatus, a user terminal, a communication system and a communication control method that can support the diversification of communication. In a base station apparatus, downlink measurement object signals are pre-coded using precoding weights that are specific to a user terminal, and transmitted to the user terminal, and, in the user terminal, the downlink measurement object signals are demodulated using the precoding weights that are specific to the user terminal, and measurement processes are performed based on the demodulated downlink measurement object signals.

1 . A base station apparatus comprising:
 a precoding processing section configured to pre-code at least one of a synchronization signal and a broadcast signal using a precoding weight that is specific to a user terminal; and   a transmission section configured to transmit the at least one of the synchronization signal and the broadcast signal having been pre-coded in the precoding processing section, to the user terminal,   wherein the transmission section provides the user terminal with information about the precoding weight that is specific to the user terminal.   
     
     
         2 . The base station apparatus according to  claim 1 , wherein the precoding processing section pre-codes the at least one of the synchronization signal and the broadcast signal using a precoding weight that is used to pre-code a downlink shared data channel signal for the user terminal. 
     
     
         3 . The base station apparatus according to  claim 1 , further comprising a power control section configured to execute power control for the at least one of the synchronization signal and the broadcast signal using a power control value that is specific to the user terminal,
 wherein the transmission section transmits the at least one of the synchronization signal and the broadcast signal having been pre-coded in the precoding processing section and subjected to the power control in the power control section, to the user terminal.   
     
     
         4 . The base station apparatus according to  claim 1 , wherein the information about the precoding weight that is specific to the user terminal is included in control information to be provided to the user terminal. 
     
     
         5 . The base station apparatus according to  claim 3 , wherein the power control value that is specific to the user terminal is reported to the user terminal. 
     
     
         6 . A user terminal comprising:
 a receiving section configured to receive at least one of a synchronization signal and a broadcast signal that is pre-coded using a precoding weight that is specific to the user terminal;   a demodulation section configured to demodulate the at least one of the synchronization signal and the broadcast signal using the precoding weight; and   a measurement section configured to perform a measurement process based on the at least one of the synchronization signal and the broadcast signal having been demodulated,   wherein the receiving section receives information about the precoding weight provided from a base station apparatus, and   the demodulation section demodulates the at least one of the synchronization signal and the broadcast signal using the information about the precoding weight.   
     
     
         7 . The user terminal according to  claim 6 , wherein the receiving section receives the information about the precoding weight in control information or DM-RS (DeModulation-Reference Signal). 
     
     
         8 . The user terminal according to  claim 6 , wherein the measurement section performs the measurement process based on the at least one of the synchronization signal and the broadcast signal having been adjusted based on a power control value that is specific to the user terminal. 
     
     
         9 . The user terminal according to  claim 8 , wherein the measurement section adjusts the at least one of the synchronization signal and the broadcast signal using the power control value that is reported from the base station apparatus. 
     
     
         10 . A user terminal comprising:
 a receiving section configured to receive at least one of a synchronization signal and a broadcast signal, and a specific signal that is pre-coded using a precoding weight that is specific to the user terminal, from a base station apparatus;   a demodulation section configured to demodulate the at least one of the synchronization signal and the broadcast signal;   a measurement section configured to perform a measurement process based on the at least one of the synchronization signal and the broadcast signal; and   a correction section configured to correct a measurement result in the measurement section using the precoding weight that is used to pre-code the specific signal,   wherein the receiving section receives information about the precoding weight provided from the base station apparatus.   
     
     
         11 . The user terminal according to  claim 10 , wherein:
 the receiving section receives the specific signal having been subjected to power control using a power control value that is specific to the user terminal; and   the correction section corrects the measurement result in the measurement section using the power control value that is used in the power control of the specific signal.   
     
     
         12 . A user terminal comprising:
 a receiving section configured to receive at least one of a synchronization signal and a broadcast signal, and a specific signal that is pre-coded using a precoding weight that is specific to the user terminal, from a base station apparatus;   a demodulation section configured to demodulate the at least one of the synchronization signal and the broadcast signal;   a measurement section configured to perform a measurement process based on the at least one of the synchronization signal and the broadcast signal having been demodulated; and   a transmission section configured to transmit a measurement result in the measurement section and the precoding weight that is used to pre-code the specific signal, to the base station apparatus,   wherein the receiving section receives information about the precoding weight provided from the base station apparatus.   
     
     
         13 . The user terminal according to  claim 12 , wherein:
 the receiving section receives the specific signal, having been subjected to power control using a power control value that is specific to the user terminal; and   the transmission section transmits the power control value that is used in the power control of the specific signal, to the base station apparatus.   
     
     
         14 . A communication system comprising:
 a base station apparatus comprising:   a precoding processing section configured to pre-code at least one of a synchronization signal and a broadcast signal using a precoding weight that is specific to a user terminal; and   a transmission section configured to transmit the at least one of the synchronization signal and the broadcast signal having been pre-coded in the precoding processing section, to the user terminal; and   the user terminal comprising:   a receiving section configured to receive the at least one of the synchronization signal and the broadcast signal having been pre-coded using the precoding weight;   a demodulation section configured to demodulate the at least one of the synchronization signal and the broadcast signal using the precoding weight; and   a measurement section configured to perform a measurement process based on the at least one of the synchronization signal and the broadcast signal having been demodulated,   wherein the receiving section receives information about the precoding weight provided from the base station apparatus, and   the demodulation section demodulates the at least one of the synchronization signal and the broadcast signal using the information about the precoding weight.   
     
     
         15 . A communication control method comprising the steps of:
 in a base station apparatus:   pre-coding at least one of a synchronization signal and a broadcast signal using a precoding weight that is specific to a user terminal; and   transmitting the at least one of the synchronization signal and the broadcast signal having been pre-coded to the user terminal; and   in the user terminal:   receiving the at least one of the synchronization signal and the broadcast signal having been pre-coded using the precoding weight;   demodulating the at least one of the synchronization signal and the broadcast signal using the precoding weight; and   performing a measurement process based on the at least one of the synchronization signal and the broadcast signal having been demodulated,   wherein the user terminal demodulates the at least one of the synchronization signal and the broadcast signal using information about the precoding weight provided from the base station apparatus.   
     
     
         16 . The base station apparatus according to  claim 1 , wherein the transmission section provides the user terminal with the information about the precoding weight that is specific to the user terminal by a downlink control channel and/or higher layer signaling. 
     
     
         17 . The base station apparatus according to  claim 1 , wherein when pre-coding the channel state information reference signal using the precoding weight that is specific to the user terminal, the transmission section notifies the user terminal of execution of pre-coding by at least one of a downlink control channel, a broadcast signal and higher layer signaling.