Communication system, base station and communication terminal

Abstract

A base station device is configured to set, for each communication terminal device, a radio format for signals transmitted to and received from the communication terminal device. The radio format is set for each communication terminal device in accordance with, for example, a type of use including a moving speed of the communication terminal device. The base station device may be configured to change the radio format for the communication terminal device based on the information about a change in the environment of a radio communication between the communication terminal device and the base station device and a change including the communication terminal device's location. The signals transmitted and received between the base station device and the communication terminal device include radio formats in which at least one of a length of a symbol of the signal and a length of a cyclic prefix in an OFDM scheme differs.

1 . (canceled) 
     
     
         2 . A communication system comprising:
 a plurality of communication terminals; and   at least one base station that configures a plurality of cells for performing radio communication with the plurality of communication terminals,   wherein the at least one base station configures:
 a first cell in accordance with a first radio format; and 
 a second cell neighboring the first cell in accordance with a second radio format that is different from the first radio format in at least one of an orthogonal frequency domain multiplexing (OFDM) symbol length and a cyclic prefix (CP) length, and 
 a first interval between timings at which specific reference signal insertion in the first radio format is started and a second interval between timings at which specific reference signal insertion in the second radio format is started are the same. 
   
     
     
         3 . The communication system according to  claim 2 , wherein the first interval in the first radio format is caused to match the second interval in the second radio format in which at least one of the OFDM symbol length and the CP length is greater than that in the first radio format. 
     
     
         4 . The communication system according to  claim 2 , wherein a specific reference signal insertion interval in a time direction and a frequency direction in the first radio format and the second radio format is changed in accordance with a characteristic of each of the communication terminals. 
     
     
         5 . A base station that configures a plurality of cells for performing radio communication with a communication terminal,
 wherein the base station configures a first cell in accordance with a first radio format,   a second cell neighboring the first cell is configured by the base station or another base station in accordance with a second radio format that is different from the first radio format in at least one of an orthogonal frequency domain multiplexing (OFDM) symbol length and a cyclic prefix (CP) length, and   a first interval between timings at which specific reference signal insertion in the first radio format is started and a second interval between timings at which specific reference signal insertion in the second radio format is started are the same.   
     
     
         6 . A communication terminal that performs radio communication with a base station via a cell configured by the base station,
 wherein a first cell used for radio communication between the communication terminal and the base station is configured by the base station in accordance with a first radio format,   a second cell neighboring the first cell is configured by the base station or another base station in accordance with a second radio format that is different from the first radio format in at least one of an orthogonal frequency domain multiplexing (OFDM) symbol length and a cyclic prefix (CP) length, and   a first interval between timings at which specific reference signal insertion in the first radio format is started and a second interval between timings at which specific reference signal insertion in the second radio format is started are the same.