Device and method

Abstract

[Object] To make it possible to retransmit downlink data with a high degree of certainty when a frequency band shared by a plurality of wireless communication systems is used in a cellular system. [Solution] Provided is a device, including: a control unit configured to control transmission of downlink data in a manner that the transmission of the downlink data is performed using a first frequency band shared by a plurality of wireless communication systems including a cellular system. The control unit controls retransmission of the downlink data in a manner that the retransmission of the downlink data is performed using a second frequency band for the cellular system.

1 . A device, comprising:
 a control unit configured to:
 control transmission of downlink data on a first frequency band shared by a plurality of wireless communication systems including a cellular system, 
 control retransmission of the downlink data on a second frequency band for the cellular system,
 wherein the retransmission on the second frequency band is within a limited time period. 
 
   
     
     
         2 . The device according to  claim 1 , wherein the control unit is further configured to:
 determine receipt of an acknowledgement associated with reception of the downlink data; and   control the retransmission of the downlink data based on a determination of a lack of the reception of the acknowledgement.   
     
     
         3 . The device according to  claim 2 , wherein:
 the transmission of the downlink data on the first frequency band is within a first time period, and   a start time of the limited time period starts before an end time of the first time period such that the retransmission of the downlink data on the second frequency band is executed before release of the first frequency band.   
     
     
         4 . The device according to  claim 1 , wherein:
 the control unit is further configured to control transmission of downlink control information to a terminal device based on allocation of the first frequency band, and   the downlink control information indicates that the transmission of the downlink data.   
     
     
         5 . The device according to  claim 4 , wherein:
 the downlink control information is information based on a format, and   the format includes a first field that indicates a shared band used for the transmission of the downlink data.   
     
     
         6 . The device according to  claim 5 , wherein the control unit is further configured to notify the terminal device of at least two bit pattern candidates corresponding to the shared band included in the first field and shared frequency bands corresponding to at least two bit patterns. 
     
     
         7 . The device according to  claim 5 , wherein the format includes a second field that indicates a retransmission control process for the downlink data. 
     
     
         8 . The device according to  claim 7 , wherein
 the retransmission control process is a hybrid automatic repeat request (HARQ) process, and   the second field is a HARQ process number field.   
     
     
         9 . The device according to  claim 5 , wherein the format excludes a field that indicates whether resource allocation is for one of transmission of new data or for retransmission. 
     
     
         10 . The device according to  claim 1 , wherein
 the downlink data is transmitted to a terminal device that supports carrier aggregation,   the first frequency band is a secondary component carrier for the terminal device, and   the second frequency band is one of a primary component carrier or the secondary component carrier for the terminal device.   
     
     
         11 . The device according to  claim 1 , wherein the first frequency band is a channel of a wireless local area network (WLAN).