Communications method, communications apparatus and communications system using same communications apparatus

• US 7,003,710 B2
• Filed: 10/12/2001
• Issued: 02/21/2006
• Est. Priority Date: 10/13/2000
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Ohtani, Yoshihiro, Tomaru, Tomonobu
• Primary Examiner(s): TORRES, JOSEPH D
• Application Number:
  US09/974,799
• Publication Number:
  US 20020046380A1
• Time in Patent Office: 1,593 Days
• Field of Search: 714/750, 714/751, 714/748, 714/749
• US Class Current: 714/751
• CPC Class Codes: H03M 13/35 Unequal or adaptive error protection, e.g. by providing a different level of protection according to significance of source information or by adapting the coding according to the change of transmission channel characteristics
• CPC Class Codes: H04L 1/1819 with retransmission of additional or different redundancy

Abstract

A communications method carries out error-correction encoding of data, generation of a suitable packet in accordance with a retransmission request from a receiving side, and transmission of the packet to the receiving side, from a transmission side. In the receiving side, the communications method performs error-correction decoding of the received data, distinguishing an uncorrectable block in accordance with a result of the error-correction decoding, and transmission of a retransmission request packet to the transmitting side. In this way, if a block in the packet is judged as uncorrectable by the receiving side, where one packet is composed of a plurality of correction blocks of error correction codes of a block type, it is possible to retransmit only the block to be retransmitted. Therefore, it is possible to avoid unnecessary use of bands and to attain a low bit rate.

Claims

1. A communications method for a communication system having a transmitting end and receiving end, in which a payload of a data packet is composed of a plurality of error correction blocks, each error correction block having a block-type error correction code, comprising the steps of:

performing error correction decoding for each of said plurality of error correction blocks in said data packet at a receiving end;

transmitting an error correction state of each of said error correction blocks from said receiving end to a transmitting end; and

extending the size of the payload of a packet to be transmitted next or subsequently from the transmitting end by adding an error correction block, a retransmission of which has been requested, to the error correction blocks in the data packet to be transmitted next or subsequently, thereby increasing the number of error correction blocks in the data packet to be transmitted next or subsequently.

2. The communications method as set forth in claim 1, wherein:

the data packet contains a retransmission-block field where the block, a retransmission of which has been requested, is added, the field being not used in an ordinary state where there is no retransmission request; and

if a retransmission of more blocks than the retransmission-block field has been requested, some blocks to be transmitted in the data packet to which are added the blocks, a retransmission of which has been requested, are added to a subsequent data packet for transmission using the retransmission-block fields.

3. The communications method as set forth in claim 1, wherein said error correction state of each error correction block includes identification information of a block that is most lately outputted from said transmitting end, among blocks received by said receiving end.

4. The communications method as set forth in claim 1, wherein said error correction state of each error correction block includes identification information of a block last outputted from said transmitting end, among blocks received by said receiving end and a number of blocks for which error-correction decoding has finished.

5. A communications apparatus, which transmits a data packet, a payload for the data packet is composed of a plurality of blocks, so as to communicate, comprising:

a receiver end performing error correction decoding for each of said plurality of blocks received from a transmitter end;

said transmitter end, when having received a request for a retransmission of an undecodable block from said receiver end, extending the size of the payload of the data packet to be transmitted next or subsequently from the transmitter end by adding the block, a retransmission of which has been requested, to the blocks constituting the data packet to be transmitted next or subsequently, thereby increasing the number of blocks in the data packet to be transmitted next or subsequently.

6. The communications apparatus as set forth in claim 5, wherein:

the data packet contains a retransmission-block field where the block, a retransmission of which has been requested, is added, the field being not used in an ordinary state where there is no retransmission request; and

if a retransmission of more blocks than the retransmission-block field has been requested, some blocks to be transmitted in the data packet to which are added the blocks, a retransmission of which has been requested, are added to a subsequent data packet for transmission using the retransmission-block fields.

7. The communications apparatus as set forth in claim 5, wherein the block, a retransmission of which has been requested, is added at a head of the data packet to be transmitted next or subsequently.

8. The communications apparatus as set forth in claim 5, wherein the block, a retransmission of which has been requested, is added between a head and a tail of the data packet to be transmitted next or subsequently.

9. The communications apparatus as set forth in claim 5, wherein the block, a retransmission of which has been requested, is added at a tail of the data packet to be transmitted next or subsequently.

10. The communications apparatus as set forth in claim 5, wherein the data packet has a fixed number of blocks.

11. The communications apparatus as set forth in claim 5, wherein the data packet has a variable number of blocks.

12. A communications apparatus, which transmits a data packet, a payload of the data packet is composed of a plurality of blocks, each block having a block-type error correction code so as to communicate, comprising:

a receiver end performing error correction decoding for each of said plurality of blocks received from a transmitter end;

said transmitter end, when having received a request for a retransmission of an undecodable block from said receiver end, extending the size of the payload of the data packet to be transmitted next or subsequently from the transmitter end by adding the block, a retransmission of which has been requested, to the blocks constituting the data packet to be transmitted next or subsequently, thereby increasing the number of blocks in the data packet to be transmitted next or subsequently.

13. The communications apparatus as set forth in claim 12, wherein:

the data packet contains a retransmission-block field where the block, a retransmission of which has been requested, is added, the field being not used in an ordinary state where there is no retransmission request; and

if a retransmission of more blocks than the retransmission-block field has been requested, some blocks to be transmitted in the data packet to which are added the blocks, a retransmission of which has been requested, are added to a subsequent data packet for transmission using the retransmission-block field.

14. The communications apparatus as set forth in claim 12, wherein the block, a retransmission of which has been requested, is added at a head of the data packet to be transmitted next or subsequently.

15. The communications apparatus as set forth in claim 12, wherein the block, a retransmission of which has been requested, is added between a head and a tail of the data packet to be transmitted next or subsequently.

16. The communications apparatus as set forth in claim 12, wherein the block, a retransmission of which has been requested, is added at a tail of the data packet to be transmitted next or subsequently.

17. The communications apparatus as set forth in claim 12, wherein the data packet has a fixed number of blocks.

18. The communications apparatus as set forth in claim 12, wherein the data packet has a variable number of blocks.

19. A communications system, including:

a communications apparatus which receives a data packet, a payload of the data packet is composed of a plurality of blocks, performs error correction decoding on said plurality of blocks, selects only an undecodable block out of said plurality of blocks, and transmits a request for a retransmission of the undecodable block; and

another communications apparatus which transmits a data packet, a payload of the data packet is composed of a plurality of blocks and when having received a request for a retransmission of an undecodable block, extends the size of the payload of the data packet to be transmitted next or subsequently by adding the block, a retransmission of which has been requested, to the blocks constituting the data packet to be transmitted next or subsequently, thereby increasing a number of blocks in the data packet to be transmitted next or subsequently,

a data packet receiving end transmits, to a data packet transmitting end, a request for a retransmission of only an undecodable block out of a data packet that has been received; and

the data packet transmitting end, in response to the request for a retransmission, retransmits a corresponding block.

20. A communications system, including:

a communications apparatus which receives a data packet, a payload of the data packet is composed of a plurality of blocks, performs error correction decoding on said plurality of blocks, selects only an undecodable block out of plurality of blocks that has been received, and transmits a request for a retransmission of the undecodable block; and

another communications apparatus which transmits a data packet, a payload of the data packet is composed of a plurality of blocks of block-type error correction codes, and when having received a request for a retransmission of an undecodable block, extends the size of the payload of a data packet to be transmitted next of subsequently by adding the block, a retransmission of which has been requested, to the blocks constituting the data packet to be transmitted next or subsequently, thereby increasing the number of blocks in the data packet to be transmitted next or subsequently,

a data packet receiving end transmits, to a data packet transmitting end, a request for a retransmission of only an undecodable block out of a data packet that has been received; and

the data packet transmitting end, in response to the request for a retransmission, retransmits a corresponding block.