Communication control method, base station, user terminal, processor, and storage medium

Abstract

A communication control method used in a cellular mobile communication system that supports inter-terminal communication that is direct radio communication capable of being performed between user terminals in a state where a radio connection with a network is established, comprises a step of transmitting, by a base station, maximum power information indicating maximum transmission power permitted in the inter-terminal communication.

1 . A communication control method used in a cellular mobile communication system that supports inter-terminal communication that is direct radio communication capable of being performed between user terminals in a state where a radio connection with a network is established, comprising:
 a step of transmitting, by a base station, maximum power information indicating maximum transmission power permitted in the inter-terminal communication.   
     
     
         2 . The communication control method according to  claim 1 , wherein, in the step of transmitting, the base station transmits the maximum power information over a broadcast channel. 
     
     
         3 . The communication control method according to  claim 1 , further comprising: a step of notifying, by a user terminal performing the inter-terminal communication, the base station that the maximum transmission power is exceeded when transmission power in the inter-terminal communication exceeds the maximum transmission power indicated by the maximum power information. 
     
     
         4 . The communication control method according to  claim 3 , further comprising: a step of controlling, by the base station, so that the inter-terminal communication is stopped in response to the reception of the notification from the user terminal. 
     
     
         5 . The communication control method according to  claim 1 , further comprising: a step of notifying, by one user terminal performing the inter-terminal communication, another user terminal performing the inter-terminal communication, of transmission power of a radio signal, when the one user terminal transmits the radio signal to the other user terminal. 
     
     
         6 . The communication control method according to  claim 5 , further comprising:
 a step of measuring, by the other user terminal, received power of the radio signal; and   a step of controlling, by the other user terminal, transmission power in transmitting a radio signal to the one user terminal on the basis of a difference between the measured received power and the notified transmission power.   
     
     
         7 . The communication control method according to  claim 1 , further comprising: a step of determining, by the base station, the maximum transmission power in accordance with propagation loss between the base station and a user terminal performing the inter-terminal communication. 
     
     
         8 . A base station used in a cellular mobile communication system that supports inter-terminal communication that is direct radio communication capable of being performed between user terminals in a state where a radio connection with a network is established, comprising:
 a processor that performs a process for transmitting maximum power information indicating maximum transmission power permitted in the inter-terminal communication.   
     
     
         9 . A user terminal that supports inter-terminal communication that is direct radio communication capable of being performed between user terminals in a state where a radio connection with a network is established, comprising:
 a processor that performs a process for receiving maximum power information indicating maximum transmission power permitted in the inter-terminal communication.   
     
     
         10 . A processor provided in a user terminal that supports inter-terminal communication that is direct radio communication capable of being performed between user terminals in a state where a radio connection with a network is established, wherein
 the processor performs a process for receiving maximum power information indicating maximum transmission power permitted in the inter-terminal communication.   
     
     
         11 . A storage medium provided in a user terminal that supports inter-terminal communication that is direct radio communication capable of being performed between user terminals in a state where a radio connection with a network is established, wherein
 the storage medium stores therein a program for the user terminal to perform a process for receiving maximum power information indicating maximum transmission power permitted in the inter-terminal communication.