Communication apparatus and communication method

• US 8,312,352 B2
• Filed: 12/07/2009
• Issued: 11/13/2012
• Est. Priority Date: 12/09/2008
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Suneya, Toru
• Primary Examiner(s): Maskulinski, Michael
• Application Number:
  US12/632,606
• Publication Number:
  US 20100146352A1
• Time in Patent Office: 1,072 Days
• Field of Search: None
• US Class Current: 714/776
• CPC Class Codes: H04L 1/0045 Arrangements at the receiver end
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements

Abstract

A communication apparatus which can communicate a data packet, a recovery packet used to recover a data packet that failed to be communicated, and a retransmit packet for the data packet that failed to be communicated, the communication apparatus includes a determining unit configured to determine, when a first packet of a plurality of packets that failed to be communicated is normally communicated, a packet that can be recovered, from among the plurality of the packets that failed to be communicated based on the first packet and the normally communicated recovery packet, and a retransmit determination unit configured to determine not to retransmit at least a part of the plurality of packets that can be recovered, when the first data packet is retransmitted which is determined to recover a plurality of data packets if it is normally communicated.

Claims

1. A communication apparatus which can communicate a data packet, a recovery packet used to recover a data packet that failed to be communicated, and a retransmit packet for the data packet that failed to be communicated, the communication apparatus comprising:

a determining unit configured to determine, when a first packet of a plurality of packets that failed to be communicated is normally communicated, a packet that can be recovered, from among the plurality of the packets that failed to be communicated based on the first packet and the normally communicated recovery packet; and

a retransmit determination unit configured to determine not to retransmit at least a part of the plurality of packets that can be recovered, when the first data packet is retransmitted which is determined to recover a plurality of data packets if it is normally communicated.

2. A communication apparatus which can communicate a data packet and a recovery packet used to recover a data packet that failed to be communicated, the communication apparatus comprising:

a determining unit configured to determine, when a first packet of a plurality of packets that failed to be communicated is normally communicated, a packet that can be recovered, from among the plurality of the packets that failed to be communicated based on the first packet and the normally communicated recovery packet; and

a retransmit determination unit configured to determine a packet to be retransmitted with the first packet from the plurality of packets that failed to be communicated, except the packet that can be recovered.

3. A communication apparatus for packet communication, comprising:

a determining unit configured to determine a packet that can be recovered when a first packet of a plurality of packets that failed to be communicated is normally communicated; and

a retransmit determination unit configured to determine a retransmit packet so that at least a part of the plurality of packets that can be recovered is not retransmitted, when the first packet that is determined to recover a plurality of packets if it is normally communicated is retransmitted.

4. The communication apparatus according to claim 3, wherein the retransmit determination unit determines a number of packets to be retransmitted with the first packet from among the packets that can be recovered, according to a number of the packets that can be recovered when the first packet is normally communicated.

5. The communication apparatus according to claim 3, wherein the determining unit determines a packet that can be recovered based on the first packet and the recovery packet that is communicated to recover the failed packets and normally communicated.

6. The communication apparatus according to claim 3, further comprising:

an obtaining unit configured to obtain an error rate corresponding to a number of the packets that failed to be communicated,

wherein when a number of packets which have a second error rate that is higher than a first error rate and are determined to be recoverable, is a first number of packets, the retransmit determination unit determines a number of retransmit packets to be smaller than a number of retransmit packets in a case where the error rate is the first error rate and a number of packets that are determined to be recoverable is the first number of the packets.

7. The communication apparatus according to claim 3, further comprising:

an obtaining unit configured to obtain an error rate corresponding to a number of the packets that failed to be communicated,

wherein when the error rate is a second error rate that is higher than a first error rate, the retransmit determination unit determines the retransmit packet so that a packet which includes moving image data that is not coded by referring to the other frame of data is retransmitted, from among the packets that failed to be communicated.

8. The communication apparatus according to claim 3, further comprising:

an obtaining unit configured to obtain delay time information about delay time required for a packet to be transmitted and received,

wherein when the obtaining unit obtains delay time information about first delay time, and then obtains delay time information about second delay time which is longer than the first delay time, and when a number of packets that are determined to be recoverable is a first number of packets, the retransmit determination unit determines the retransmit packet so that a second number of packets are retransmitted, from among the first number of packets that are determined to be recoverable, and

when the obtaining unit obtains the delay time information about first delay time, and then obtains delay time information about third delay time which is longer than the second delay time, and when the number of packets that are determined to be recoverable is the first number of packets, the retransmit determination unit determines the retransmit packet so that a third number of packets which is smaller than the second number of packets are retransmitted, from among the first number of packets that are determined to be recoverable.

9. The communication apparatus according to claim 3, wherein the retransmit determination unit determines whether to retransmit the packets that failed to be communicated according to whether the packets that failed to be communicated includes moving image data that is coded by referring to the other frame of data.

10. The communication apparatus according to claim 3, further comprising:

an obtaining unit configured to obtain delay time information about delay time required for a packet to be transmitted and received,

wherein when the obtaining unit obtains delay time information about first delay time, and then obtains delay time information about second delay time which is longer than the first delay time, the retransmit determination unit determines the retransmit packet so that a packet which includes moving image data that is coded by referring to the other frame of data and a packet which includes moving image data that is not coded by referring to the other frame of data are retransmitted, from among the packet that are determined to be recoverable, and

when the obtaining unit obtains the delay time information about the first delay time, and then obtains delay time information about third delay time which is longer than the second delay time, the retransmit determination unit determines the retransmit packet so that a packet which includes moving image data that is not coded by referring to the other frame of data is retransmitted, from among the packet that are determined to be recoverable.

11. The communication apparatus according to claim 3,

wherein the determining unit determines a packet that can be recovered when a second packet is normally communicated, from among a plurality of packets that cannot be recovered when the first packet is normally communicated, and

the retransmit determination unit determines the retransmit packet so that at least a part of the plurality of packets that are determined to be recoverable when the second packet is normally communicated is not retransmitted, when the first and second packets that are determined to recover the plurality of packets if they are normally communicated are retransmitted.

12. A transmission apparatus, comprising:

a transmission unit configured to transmit a recovery packet which is used by a reception device to recover a data packet that has failed to be communicated, and a data packet to the reception device;

a reception unit configured to receive a request for retransmitting a data packet;

a determining unit configured to determine a data packet that can be recovered by the reception device based on reception of a first data packet, from among a plurality of the data packets requested for retransmission, and

a retransmit determination unit configured to determine a data packet to be retransmitted so that at least a part of the plurality of packets that are determined to be recoverable is not retransmitted, when a number of the data packets requested for retransmission exceeds a predetermined number and when the first data packet that is determined to recover a plurality of data packets by the determining unit is retransmitted.

13. A reception device, comprising:

a reception unit configured to receive a recovery packet which is used to recover a data packet that failed to be communicated, and a data packet;

an identifying unit to identify a data packet that cannot be recovered by the recovery packet, from among the data packet that failed to be communicated;

a determining unit configured to determine a data packet that can be recovered based on reception of a first data packet, from among a plurality of data packets that cannot be recovered; and

a retransmit determination unit configured to determine a data packet which is required to be retransmitted so that at least a part of the plurality of data packets that are determined to be recoverable is not retransmitted, when a number of the data packets that cannot be recovered by the recovery packets exceeds a predetermined number and when retransmission of the first data packet that is determined to recover a plurality of data packets by the determining unit is requested.

14. A method for communication performed by a communication apparatus which can communicate a data packet, a recovery packet used to recover a data packet that failed to be communicated, and a retransmit packet for the data packet that failed to be communicated, the method comprising:

determining, when a first packet of a plurality of packets that failed to be communicated is normally communicated, a packet that can be recovered, from among the plurality of the packets that failed to be communicated based on the first packet and the normally communicated recovery packet; and

determining not to retransmit at least a part of the plurality of packets that can be recovered, when the first data packet is retransmitted which is determined to recover a plurality of data packets if it is normally communicated.

15. A non-transitory storage medium which stores a program to cause a computer which can communicate a data packet, a recovery packet used to recover a data packet that failed to be communicated, and a retransmitted packet for the data packet that failed to be communicated to execute a method comprising:

determining, when a first packet of a plurality of packets that failed to be communicated is normally communicated, a packet that can be recovered, from among the plurality of the packets that failed to be communicated based on the first packet and the normally communicated recovery packet; and

determining not to retransmit at least a part of the plurality of packets that can be recovered, when the first data packet is retransmitted which is determined to recover a plurality of data packets if it is normally communicated.

16. A communication method performed by a communication apparatus for packet communication, the method comprising:

determining a packet that can be recovered when a first packet of a plurality of packets that failed to be communicated is normally communicated; and

determining a retransmit packet so that at least a part of the plurality of packets that can be recovered is not retransmitted, when the first packet that is determined to recover a plurality of packets if it is normally communicated and retransmitted.