Communication system, communication terminal, and base station

Abstract

A radio communication technology for enabling high reliability, a high transmission rate, and low power consumption is provided. A communication system includes a communication terminal and a base station. The base station includes a plurality of transmitter-receivers configured to perform radio communication with the communication terminal. The base station is configured to perform radio communication with the communication terminal by using a part or all of the plurality of transmitter-receivers. The communication terminal receives a downlink synchronization signal from at least one first transmitter-receiver to be newly connected, and establishes downlink synchronization with the at least one first transmitter-receiver by using the downlink synchronization signal. The communication terminal establishes uplink synchronization with the at least one first transmitter-receiver through random access processing.

1 . A communication system comprising:
 a communication terminal; and   a base station including a plurality of transmitter-receivers configured to perform radio communication with the communication terminal, the base station being configured to perform radio communication with the communication terminal by using a part or all of the plurality of transmitter-receivers, wherein   the communication terminal receives a downlink synchronization signal from at least one first transmitter-receiver to be newly connected, and establishes downlink synchronization with the at least one first transmitter-receiver by using the downlink synchronization signal, and   the communication terminal establishes uplink synchronization with the at least one first transmitter-receiver through random access processing.   
     
     
         2 . The communication system according to  claim 1 , wherein
 the base station transmits a start command of the random access processing to the communication terminal via a transmitter-receiver being currently connected to the communication terminal, and   the communication terminal starts the random access processing by receiving the start command.   
     
     
         3 . The communication system according to  claim 1 , wherein
 the communication terminal autonomously starts the random access processing.   
     
     
         4 . The communication system according to  claim 1 , wherein
 the base station transmits, to the communication terminal, a release command for releasing connection between the communication terminal and at least one second transmitter-receiver via a transmitter-receiver being currently connected to the communication terminal, and   the communication terminal releases the connection with the at least one second transmitter-receiver in accordance with the release command.   
     
     
         5 . A communication terminal being configured to perform radio communication with a base station including a plurality of transmitter-receivers via a part or all of the plurality of transmitter-receivers, wherein
 the communication terminal receives a downlink synchronization signal from at least one first transmitter-receiver to be newly connected, and establishes downlink synchronization with the at least one first transmitter-receiver by using the downlink synchronization signal, and   the communication terminal establishes uplink synchronization with the at least one first transmitter-receiver through random access processing.   
     
     
         6 . A base station being configured to perform radio communication with a communication terminal, wherein
 the base station includes a plurality of transmitter-receivers, and is configured to perform radio communication with the communication terminal by using a part or all of the plurality of transmitter-receivers, and   when the communication terminal starts random access processing, the base station performs the random access processing with the communication terminal via at least one first transmitter-receiver to be newly connected to the communication terminal.