Data transmission apparatus, data reception apparatus, and data transmission and reception system

A data transmission and reception system for transmitting and receiving copyrighted data having a use limit based on a copyright, comprising:

• a data transmission apparatus;
• and
• a data reception apparatus,
• wherein said data transmission apparatus includes:
• a control information generation unit configured to generate use control information indicating that the copyrighted data is available within a predetermined use limit in said data transmission and reception system, the use control information including use-control-information confirmation interval that indicates an interval time for periodically measuring a round trip time taken for transmitting and receiving a predetermined measuring packet;
• a proximity confirmation unit configured to measure the round trip time to said data reception apparatus;
• and
• a use information management unit configured to control transmission of validity information of the use control information to said data reception apparatus in the case where the measured round trip time is equal to or less than a predetermined time, and
• said data reception apparatus includes:
• a proximity confirmation unit configured to transmit and receive the predetermined measuring packet between said data reception apparatus and said data transmission apparatus;
• a use information management unit configured to control reception of the use control information and the copyrighted data from said data transmission apparatus;
• and
• a use information confirmation unit configured to request said data transmission apparatus to measure the round trip time based on the use-control-information confirmation interval included in the received use control information,
• wherein said use information management unit of said data reception apparatus is further configured to invalidate the received use control information in the case where the use-control-information confirmation interval is exceeded without receiving the validity information of the use control information from said data transmission apparatus

A data transmission apparatus that transmits copyrighted data having a use limit based on a copyright, in a data transmission and reception system, said data transmission apparatus comprising:

• a use information generation unit configured to generate use control information indicating that the copyrighted data is available overall within a predetermined use limit in said data transmission and reception system, the use control information including use-control-information confirmation interval that indicates an interval time for periodically measuring a round trip time taken for transmitting and receiving a predetermined measuring packet;
• a proximity confirmation unit configured to measure the round trip time in response to a request from the data reception apparatus after the transmission of the use control information and the copyrighted data;
• and
• a use information management unit configured to control transmission of validity information of the use control information to the data reception apparatus in the case where the measured round trip time is equal to or less than the predetermined time.

A data reception apparatus that receives copyrighted data having a use limit based on a copyright from a data transmission apparatus, in a data transmission and reception system, said data reception apparatus comprising:

• a proximity confirmation unit configured to transmit and receive a predetermined measuring packet, to and from the data transmission apparatus;
• a use information management unit configured to control reception of use control information and the copyrighted data from the data transmission apparatus, and
• a use information confirmation unit configured to request the data transmission apparatus to measure a round trip time based on a use-control-information confirmation interval included in the received use control information,
• wherein said use information management unit is further configured to invalidate the received use control information in the case where the use-control-information confirmation interval is exceeded without receiving validity information of the use control information from the data transmission apparatus.

A data transmission method, used for a data transmission and reception system, for transmitting copyrighted data having a use limit based on a copyright, said data transmission method comprising:

• generating use control information indicating that the copyrighted data is available overall within a predetermined use limit in the data transmission and reception system, the use control information including use-control-information confirmation interval that indicates an interval time for periodically measuring a round trip time taken for transmitting and receiving a predetermined measuring packet;
• measuring the round trip time in response to a request from the data reception apparatus after the transmission of the use control information and the copyrighted data;
• and
• controlling transmission of validity information of the use control information to the data reception apparatus in the case where the measured round trip time is equal to or less than the predetermined time.

A data reception method of receiving copyrighted data having a use limit based on copyright from a data transmission apparatus, in a data transmission and reception system, said data reception method comprising:

• transmitting and receiving a predetermined measuring packet, to and from the data transmission apparatus;
• controlling reception of use control information and the copyrighted data from the data transmission apparatus;
• and
• requesting the data transmission apparatus to measure a round trip time based on a use-control-information confirmation interval included in the received use control information,
• wherein said requesting further includes invalidating the received use control information in the case where the use-control-information confirmation interval is exceeded without receiving validity information of the use control information from the data transmission apparatus.

A program used for a data transmission apparatus in a data transmission and reception system, the data transmission apparatus transmitting copyrighted data having a use limit based on a copyright to a data reception apparatus, said program causing a computer to execute:

• generating use control information indicating that the copyrighted data is available overall within a predetermined use limit in the data transmission and reception system, the use control information including use-control-information confirmation interval that indicates an interval time for periodically measuring a round trip time taken for transmitting and receiving a predetermined measuring packet;
• measuring the round trip time in response to a request from the data reception apparatus after the transmission of the use control information and the copyrighted data;
• and
• controlling transmission of validity information of the use control information to the data reception apparatus in the case where the measured round trip time is equal to or less than the predetermined time.

A program used for a data reception apparatus in a data transmission and reception system, the data reception apparatus receiving copyrighted data having a use limit based on a copyright from a data transmission apparatus, said program causing a computer to execute:

• transmitting and receiving a predetermined measuring packet, to and from the data transmission apparatus;
• controlling reception of use control information and the copyrighted data from the data transmission apparatus;
• and
• requesting the data transmission apparatus to measure a round trip time based on a use-control-information confirmation interval included in the received use control information,
• wherein said requesting further includes invalidating the received use control information in the case where the use-control-information confirmation interval is exceeded without receiving validity information of the use control information from the data transmission apparatus.

A computer-readable recording medium on which a program is stored, the program being used for a data transmission apparatus in a data transmission and reception system, the data transmission apparatus transmitting copyrighted data having a use limit based on a copyright to a data reception apparatus, the program causing a computer to execute:

• generating use control information indicating that the copyrighted data is available overall within a predetermined use limit in the data transmission and reception system, the use control information including use-control-information confirmation interval that indicates an interval time for periodically measuring a round trip time taken for transmitting and receiving a predetermined measuring packet;
• measuring the round trip time in response to a request from the data reception apparatus after the transmission of the use control information and the copyrighted data;
• and
• controlling transmission of validity information of the use control information to the data reception apparatus in the case where the measured round trip time is equal to or less than the predetermined time.

A computer-readable recording medium on which a program is stored, the program being used for a data reception apparatus in a data transmission and reception system, the data reception apparatus receiving copyrighted data having a use limit based on a copyright from a data transmission apparatus, the program causing a computer to execute:

• transmitting and receiving a predetermined measuring packet, to and from the data transmission apparatus;
• controlling reception of use control information and the copyrighted data from the data transmission apparatus;
• and
• requesting the data transmission apparatus to measure a round trip time based on a use-control-information confirmation interval included in the received use control information,
• wherein said requesting further includes invalidating the received use control information in the case where the use-control-information confirmation interval is exceeded without receiving validity information of the use control information from the data transmission apparatus.