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US 2002/0154600 A1Published application
Data communication system
OwnerDaiji Ido, Koji Imura +2inventors
InventorsDaiji Ido, Koji Imura, Akihiro Miyazaki, Koichi Hata
Life of this patent
Estimating the term…
Abstract
A data communication system capable of eliminating the retransmission of useless data that is too late for the playback time at the receiving side, and, accordingly, capable of eliminating the wasteful utilization of transmission band. In the system, round-trip time RTT of a packet between the server (data transmitting apparatus) 100 and the terminal apparatus (data receiving apparatus) 200 is calculated, and only when the sum of the round-trip time RTT and present time is less than the playback time of the packet, retransmission request for lost packet which has high priority is made.
Claims24
A data transmitting apparatus, comprising:
- storing means for storing a retransmittable data only;
- retransmitting means for retransmitting a data that is extracted from the data stored in said storing means corresponding to a retransmission request of a receiving side;
- calculating means for calculating a data round-trip time between the receiving side and the data transmitting apparatus;
- and
- transmitting means for transmitting the data round-trip time calculated by said calculating means to the receiving side at a predetermined time interval.
2 more elements
A data transmitting apparatus, comprising:
- storing means for storing a retransmittable data only;
- retransmitting means for retransmitting a data that is extracted from the data stored in said storing means corresponding to a retransmission request of a receiving side;
- measuring means for measuring a differential time between reception time of a first data transmitted from the receiving side and transmission time of a second data to be transmitted to the receiving side in response to the first data;
- and
- transmitting means for transmitting the differential time measured by said measuring means included in the second data to the receiving side at a predetermined time interval.
2 more elements
A data receiving apparatus, comprising:
- receiving means for receiving a data;
- loss detecting means for detecting loss of data when the data is received by said receiving means;
- playback time calculating means for calculating playback time of the data received by said receiving means;
- round-trip time receiving means for receiving a data round-trip time between a transmitting side and the data receiving apparatus;
- and
- retransmission request deciding means for deciding, when a lost data is detected by said loss detecting means, whether a retransmission request for the lost data is made or not based on the playback time calculated by said playback time calculating means and the data round-trip time received by said data round-trip time receiving means.
3 more elements
A data receiving apparatus, comprising:
- calculating means for calculating a data round-trip time between a transmitting side and the data receiving apparatus by subtracting transmission time of a first data transmitted to the transmitting side and a differential time between reception time of the first data at the transmitting side and transmission time of a second data transmitted from the transmitting side, the differential time being included in the second data, from reception time of the second data;
- receiving means for receiving a data;
- loss detecting means for detecting loss of data when the data is received by said receiving means;
- playback time calculating means for calculating playback time of the data received by said receiving means;
- and
- retransmission request deciding means for deciding, when a lost data is detected by said loss detecting means, whether a retransmission request for the lost data is made or not based on the playback time calculated by said playback time calculating means and the data round-trip time calculated by said calculating means.
3 more elements
A data communication system comprising a data transmitting apparatus and a data receiving apparatus,
- wherein the data transmitting apparatus comprises:
- storing means for storing a retransmittable data only;
- retransmitting means for retransmitting a data that is extracted from the data stored in said storing means corresponding to a retransmission request of the data receiving apparatus;
- calculating means for calculating a data round-trip time between the data receiving apparatus and the data transmitting apparatus;
- and
- transmitting means for transmitting the data round-trip time calculated by said calculating means to the data receiving apparatus at a predetermined time interval, and
- wherein the data receiving apparatus comprises:
- receiving means for receiving the data transmitted from the data transmitting apparatus;
- loss detecting means for detecting loss of data when the data is received by said receiving means;
- playback time calculating means for calculating playback time of the data received by said receiving means;
- round-trip time receiving means for receiving the data round-trip time transmitted from said transmitting means;
- and
- retransmission request deciding means for deciding, when a lost data is detected by said loss detecting means, whether a retransmission request for the lost data is made or not based on the playback time calculated by said playback time calculating means and the data round-trip time received by said round-trip time receiving means.
10 more elements
A data communication system comprising a data transmitting apparatus and a data receiving apparatus,
- wherein the data transmitting apparatus comprises:
- storing means for storing a retransmittable data only;
- retransmitting means for retransmitting a data that is extracted from the data stored in said storing means corresponding to a retransmission request of the data receiving apparatus;
- measuring means for measuring a differential time between reception time of a first data transmitted from the data receiving apparatus and transmission time of a second data to be transmitted to the data receiving apparatus in response to the first data;
- and
- transmitting means for transmitting the differential time measured by said measuring means included in the second data to the data receiving apparatus at a predetermined time interval, and
- wherein the data receiving apparatus comprises:
- calculating means for calculating a data round-trip time between the data transmitting apparatus and the data receiving apparatus by subtracting transmission time of the first data transmitted to the data transmitting apparatus and the differential time included in the second data transmitted from the data transmitting apparatus from reception time of the second data;
- receiving means for receiving the data transmitted from the data transmitting apparatus;
- loss detecting means for detecting loss of data when the data is received by said receiving means;
- playback time calculating means for calculating playback time of the data received by said receiving means;
- and
- retransmission request deciding means for deciding, when a lost data is detected by said loss detecting means, whether a retransmission request for the lost data is made or not based on the playback time calculated by said playback time calculating means and the data round-trip time calculated by said calculating means.
10 more elements
A data communication method in a data communication system comprising a data receiving apparatus and a data transmitting apparatus that retransmits a data which is extracted from the data stored in storing means for storing a retransmittable data only corresponding to a retransmission request of the data receiving apparatus, said method comprising:
- a calculating step in which the data transmitting apparatus calculates a data round-trip time between the data receiving apparatus and the data transmitting apparatus;
- a transmitting step in which the data transmitting apparatus transmits the data round-trip time calculated in the calculating step to the data receiving apparatus at a predetermined time interval;
- a receiving step in which the data receiving apparatus receives the data transmitted from the data transmitting apparatus;
- a loss detecting step in which the data receiving apparatus detects loss of data when the data is received in the receiving step;
- a playback time calculating step in which the data receiving apparatus calculates playback time of the data received in the receiving step;
- a round-trip time receiving step in which the data receiving apparatus receives the data round-trip time transmitted in the transmitting step;
- and
- a retransmission request deciding step in which the data receiving apparatus decides, when a lost data is detected in the loss detecting step, whether a retransmission request for the lost data is made or not based on the playback time calculated in the playback time calculating step and the data round-trip time received in the round-trip time receiving step.
5 more elements
A data communication method in a data communication system comprising a data receiving apparatus and a data transmitting apparatus that retransmits a data which is extracted from the data stored in storing means for storing a retransmittable data only corresponding to a retransmission request of the data receiving apparatus, said method comprising:
- a measuring step in which the data transmitting apparatus measures a differential time between reception time of a first data transmitted from the data receiving apparatus and transmission time of a second data to be transmitted to the data receiving apparatus in response to the first data;
- a transmitting step in which the data transmitting apparatus transmits the differential time measured in the measuring step included in the second data to the data receiving apparatus at a predetermined time interval;
- a calculating step in which the data receiving apparatus calculates a data round-trip time between the data transmitting apparatus and the data receiving apparatus by subtracting transmission time of the first data transmitted to the data transmitting apparatus and the differential time included in the second data transmitted from the data transmitting apparatus from reception time of the second data;
- a receiving step in which the data receiving apparatus receives the data transmitted from the data transmitting apparatus;
- a loss detecting step in which the data receiving apparatus detects loss of data when the data is received in the receiving step;
- a playback time calculating step in which the data receiving apparatus calculates playback time of the data received in the receiving step;
- and
- a retransmission request deciding step in which the data receiving apparatus decides, when a lost data is detected in the loss detecting step, whether a retransmission request for the lost data is made or not based on the playback time calculated in the playback time calculating step and the data round-trip time calculated in the calculating step.
5 more elements
Dependencies are inferred from the claim text.