Cell reselection recognition by a terminal in a communication system

Abstract

A narrow-bandwidth terminal device performs radio communication at a bandwidth narrower than a system bandwidth. The narrow-bandwidth terminal device in an idle state camps on a cell, and performs discontinuous reception of a signal transmitted from the cell. The terminal device also determines a reception condition of the signal, for example, whether the signal can be received. When it is determined that the signal cannot be received, the narrow-bandwidth terminal device moves out of a coverage area of the cell while continuing to perform the discontinuous reception. When it is determined that a discontinuous reception timer has been completed, the narrow-bandwidth terminal device continues to perform the discontinuous reception.

1 . A communication system comprising a communication terminal, and a base station that performs radio communication with the communication terminal,
 wherein the communication terminal includes a narrow-bandwidth terminal that performs radio communication with the base station at a frequency band narrower than a system bandwidth that can be used in the radio communication, the system bandwidth being a frequency band, and   the base station transmits, to the communication terminal, a base station selection parameter for the narrow-bandwidth terminal.   
     
     
         2 . The communication system according to  claim 1 ,
 wherein system information for the narrow-bandwidth terminal includes the base station selection parameter, and the base station transmits the system information to the communication terminal.   
     
     
         3 . A base station that performs radio communication with a communication terminal,
 wherein the communication terminal includes a narrow-bandwidth terminal that performs radio communication with the base station at a frequency band narrower than a system bandwidth that can be used in the radio communication, the system bandwidth being a frequency band, and   the base station transmits, to the communication terminal, a base station selection parameter for the narrow-bandwidth terminal.   
     
     
         4 . A communication terminal that performs radio communication with a base station, the communication terminal comprising
 a narrow-bandwidth terminal that performs radio communication with the base station at a frequency band narrower than a system bandwidth that can be used in the radio communication, the system bandwidth being a frequency band,   wherein the communication terminal receives, from the base station, a base station selection parameter for the narrow-bandwidth terminal.