COMMUNICATION TERMINAL AND RETRANSMISSION CONTROL METHOD

• US 20070230337A1
• Filed: 03/29/2007
• Published: 10/04/2007
• Est. Priority Date: 03/30/2006
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: IGARASHI, Ken, YAMAZAKI, Kenichi
• Granted Patent: US 7,715,314 B2
• Time in Patent Office: Days
• US Class Current: 370/230
• CPC Class Codes: H04L 1/1678 where the control information is for timing, e.g. time stamps
• CPC Class Codes: H04L 1/1848 Time-out mechanisms
• CPC Class Codes: H04L 1/1854 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 1/188 Time-out mechanisms

Abstract

A retransmission control method of the present invention includes the steps in which a receiving terminal: measures a round trip time (RTT) between the receiving terminal and a sending terminal; calculates an RTO by using the measured RTT; and starts a time counting operation of the RTO upon reception from a point in time when a segment is received from the sending terminal; transmits a segment prompt signal which prompts the sending terminal to transmit a segment, when the segment is not received from the sending terminal until the RTO is completed, and in which the sending terminal: retransmits a segment to the receiving terminal when there is a segment to be retransmitted; and transmits a data-less signal to the receiving terminal when there is a segment that should be retransmitted, the data-less signal indicating that there is no segment that should be retransmitted.

Claims

1. A communication terminal configured to receive a segment transmitted by a different terminal, comprising:

a round trip time measuring unit configured to measure a round trip time between the communication terminal and the different terminal;

a retransmission timeout time calculator configured to calculate a retransmission timeout time by using the round trip time in order to estimate a retransmission timeout time set in the different terminal;

a timer configured to start a time counting operation of the retransmission timeout time when the segment is received from the different terminal; and

a segment prompt transmitter configured to transmit, to the different terminal, a segment prompt signal for prompting the different terminal to transmit the segment when the segment is not received from the different terminal during a time from the start of the time counting operation to the completion of the retransmission timeout time.

2. The communication terminal according to claim 1, further comprising a round trip time increasing unit configured to increase a round trip time to be measured by the different terminal, by manipulating an acknowledgement to be transmitted to the different terminal.

3. The communication terminal according to claim 1, wherein

the timer restarts the time counting operation when the segment is received from the different terminal after the segment prompt signal is transmitted, and

the timer cancels a restart of the time counting operation until a new segment is received when a data-less signal is received from the different terminal after the segment prompt signal is transmitted, the data-less signal indicating that there is no segment that should be retransmitted.

4. The communication terminal according to claim 1, further comprising an application detector configured to detect an application executed by the different terminal, wherein

the segment prompt transmitter determines whether or not to transmit the segment prompt signal to the different terminal in accordance with the application detected by the application detector.

5. A communication terminal configured to transmit a segment to a different terminal, comprising:

a segment receiver configured to receive a segment prompt signal which requests a retransmission of the segment; and

a segment retransmitter configured to retransmit a segment to the receiving terminal when there is a segment that should be transmitted, and to transmit a data-less signal to the receiving terminal when there is no segment that should be retransmitted, the data-less signal indicating that there is no segment that should be retransmitted.

6. A retransmission control method for controlling a retransmission of a segment transmitted from a first communication terminal to a second communication terminal, comprising the steps of:

measuring, at the second communication terminal, a round trip time between the first and second communication terminals;

calculating at the second communication terminal, a retransmission timeout time by using the round trip time in order to estimate a retransmission timeout time set in the first communication terminal;

starting, at the second communication terminal, a time counting operation of the retransmission timeout time when the segment is received from the first communication terminal;

transmitting, from the second communication terminal to the first communication terminal, a segment prompt signal for prompting the first terminal to transmit the segment when the segment is not received to the second communication terminal from the first communication terminal during a time from the start of the time counting operation to the completion of the retransmission timeout time;

receiving, at the first communication terminal, the segment prompt signal from the second communication terminal;

retransmitting, at the first communication terminal, a segment to the second communication terminal when there is a segment that should be retransmitted; and

transmitting, at the first communication terminal, a data-less signal to the second communication terminal when there is no segment that should be retransmitted, the data-less signal indicating that there is no segment that should be retransmitted.