Data transmitting apparatus, data receiving apparatus, and data communication system

• US 20080130534A1
• Filed: 06/22/2007
• Published: 06/05/2008
• Est. Priority Date: 11/30/2006
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Tomioka, Tazuko
• Granted Patent: US 8,009,596 B2
• Time in Patent Office: Days
• US Class Current: 370/310
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/0072 Error control for data other than payload data, e.g. control data
• CPC Class Codes: H04L 1/1819 with retransmission of additional or different redundancy

Abstract

A data transmitting apparatus generates a block that includes identification information including the number of times divided data can be transmitted and data for error detection for detecting an error in the identification information associated with each other with respect to each divided data, and transmits the block to a data receiving apparatus. If the number of times divided data can be transmitted is one or more, the data transmitting apparatus stores the corresponding block in a transmission memory, and retransmits it upon a request for retransmission from the data receiving apparatus.

Claims

1. A data transmitting apparatus comprising:

a first encoding unit that encodes a packet to be transmitted based on a first error-correcting method and generates an encoded packet;

a dividing unit that divides the encoded packet and generates a plurality of divided data;

an identification-information generating unit that generates identification information unique to one of the divided data;

a computing unit that computes data for error detection in the identification information;

a second encoding unit that encodes the identification information and the data for error detection based on a second error-correcting method and generates additional information;

a block generating unit that adds the additional information to the one of the divided data and generates a block;

a transmission-data storing unit that stores the block;

a transmitting unit that transmits the block;

a receiving unit that receives retransmission requesting information for requesting retransmission of the block from an external device, when the external device having received the block detects an error in the block based on the data for error detection; and

a retransmission control unit that reads the block from the transmission-data storing unit and instructs the transmitting unit to transmit the block when the receiving unit receives the retransmission requesting information.

2. The apparatus according to claim 1, wherein the identification information includes a retransmission counter that indicates retransmissible number of times, and the data transmitting apparatus further comprises:

a storage control unit that determines whether the block including the identification information can be retransmitted based on a value of the retransmission counter included in the identification information and, stores the block in the transmission-data storing unit when the block is determined to be capable of being retransmitted.

3. The apparatus according to claim 2, wherein the storage control unit stores a block in which the retransmission counter indicates one or more in the transmission-data storing unit.

4. The apparatus according to claim 2, wherein the retransmission control unit decrements the value of the retransmission counter by one every time the block is retransmitted, and

the storage control unit deletes a block in which the retransmission counter indicates zero from the transmission-data storing unit.

5. The apparatus according to claim 2, wherein the identification-information generating unit sets a common value as an initial value of the retransmission counter in a plurality of divided data belonging to an identical packet.

6. The apparatus according to claim 5, wherein the identification-information generating unit sets one of zero and one as the initial value of the retransmission counter.

7. The apparatus according to claim 1, wherein

the identification information includes a block number indicating an order of the divided data in the block to form the packet, and

the data transmitting apparatus further comprises:

a transmission control unit that instructs the transmitting unit to transmit blocks in order of block numbers included in the identification information.

8. The apparatus according to claim 1, wherein the identification information includes a quantity information indicating a quantity of all blocks which are to be transmitted at a time that belong to an identical packet.

9. The apparatus according to claim 1, wherein

the identification information includes a packet identification information for identifying the packet to which the divided data having the identification information belongs, and

the data transmitting apparatus further comprises:

a transmission control unit that instructs the transmitting unit to transmit blocks that includes identical packet identification information at a time.

10. The apparatus according to claim 1, further comprising:

a timer that measures time, and wherein

the retransmission control unit instructs the transmitting unit to transmit the block stored in the transmission-data storing unit to the external device, when the retransmission control unit determines that a reply including the retransmission requesting information is not received from the external device within a predetermined time based on the time measured by the timer.

11. A data receiving apparatus comprising:

a receiving unit that receives each of a plurality of divided data that form a single encoded packet encoded based on a first error-correcting method from an external device in units of blocks, a block including a single divided data and additional information added thereto, the additional information including identification information unique to one of the divided data and data for error detection both of which are encoded based on a second error-correcting method;

a separating unit that separates each of the blocks into the divided data and the additional information;

a first decoding unit that performs error-correction decoding on the additional information and acquires the identification information and the data for error detection;

an error detecting unit that detects an error in the identification information based on the data for error detection;

a retransmission processing unit that generates requesting information for requesting retransmission of the block that includes the error detected by the error detecting unit in the identification information;

a transmitting unit that transmits the retransmission requesting information to an external device;

a packet synthesizing unit that synthesizes the encoded packet based on the divided data contained in the block retransmitted from the external device and other block data received in advance; and

a second decoding unit that performs error-correction decoding on the encoded packet and generates a single packet.

12. The apparatus according to claim 11, wherein

the identification information includes a retransmission counter that indicates retransmissible number of times for the block, and

the retransmission processing unit determines the divided data in which an error is detected by the error detecting unit and a value of the retransmission counter is one or more to be retransmitted.

13. The apparatus according to claim 11, wherein

the identification information includes a block number that indicates an order of the divided data in the block to form the packet, and

the packet synthesizing unit arranges the divided data in the order of the block number.

14. The apparatus according to claim 11, wherein the identification information includes packet identification information for identifying the packet to which the divided data having the identification information belongs.

15. The apparatus according to claim 14, wherein the retransmission processing unit generates retransmission requesting information for requesting retransmission of all the divided data that are to be retransmitted and include an identical packet identification information.

16. The apparatus according to claim 14, wherein the retransmission processing unit generates retransmission requesting information for requesting retransmission of divided data added with the identification information, when the error detecting unit detects errors in the identification information belonging to an identical packet at a predetermined ratio or more.

17. The apparatus according to claim 14, wherein the packet synthesizing unit synthesizes the encoded packet from all the divided data that are received regardless of a result of an error detection, when at least one of the divided data having the identical packet identification information indicates zero in the retransmission counter thereof.

18. The apparatus according to claim 14, wherein the packet synthesizing unit synthesizes the encoded packet from all the divided data that are received regardless of a result of an error detection, when the error detecting unit detects errors in the identification information belonging to an identical packet at a predetermined ratio or less.

19. The apparatus according to claim 11, further comprising:

a timer that measures time, and wherein

the packet synthesizing unit synthesizes the encoded packet from all the divided data that are received regardless of a result of an error detection, when the packet synthesizing unit determines that a block requested by the retransmission requesting information is not received from the external device within a predetermined time based on the time measured by the timer.

20. A data communication system comprising:

a data transmitting apparatus; and

a data receiving apparatus, wherein

the data transmitting apparatus includes;

a first encoding unit that encodes a packet to be transmitted based on a first error-correcting method and generates an encoded packet;

a dividing unit that divides the encoded packet and generates a plurality of divided data;

an identification-information generating unit that generates identification information unique to one of the divided data;

a computing unit that computes data for error detection in the identification information;

a second encoding unit that encodes the identification information and the data for error detection based on a second error-correcting method and generates additional information;

a block generating unit that adds the additional information to the one of the divided data and generates a block;

a transmission-data storing unit that stores the block;

a transmitting unit that transmits the block;

a receiving unit that receives retransmission requesting information for requesting retransmission of the block from an external device when the external device having received the block detects an error in the block based on the data for error detection; and

a retransmission control unit that reads the block from the transmission-data storing unit and instructs the transmitting unit to transmit the block when the receiving unit receives the retransmission requesting information, and

the data receiving apparatus includes;

a receiving unit that receives the block from the data transmitting apparatus;

a separating unit that separates each of the blocks into the divided data and the additional information;

a first decoding unit that performs error-correction decoding on the additional information and acquires the identification information and the data for error detection;

an error detecting unit that detects an error in the identification information based on the data for error detection;

a retransmission processing unit that generates requesting information for requesting retransmission of the block that includes the error detected by the error detecting unit in the identification information;

a transmitting unit that transmits the retransmission requesting information to an external device;

a packet synthesizing unit that synthesizes the encoded packet based on the divided data contained in the block retransmitted from the data transmitting apparatus and other block data received in advance; and

a second decoding unit that performs error-correction decoding on the encoded packet and generates a single packet.