JP4572933B2 - Receiving apparatus and retransmission control method - Google Patents

Description

The present invention relates to a retransmission control how contact and receiver of the packet, in particular, the transmitted encoded from the transmitter packet by returning a stepwise acknowledgment with error detection and correction at the receiver , it relates to a receiving apparatus and you retransmission control how to carry out an efficient retransmission control.

  In recent years, with the spread of ADSL (Asymmetric Digital Subscriber Line) and the like, high-speed data transmission can be used even in general homes. In addition, with the widespread use of mobile phones, high-speed data transmission is also required for mobile radio communications.

  In these applications that deliver video and audio in real time using high-speed data transmission, it is necessary to minimize the delay in data transmission. Especially, even if there is an error during data transmission, the number of retransmissions is small and the delay is minimal. Realization of efficient retransmission control that can be suppressed to a low level is desired.

  2. Description of the Related Art Conventionally, an ARQ (Automatic Repeat reQuest) system has been used as a packet transmission procedure for performing data transmission with high reliability in a communication system that performs data transmission through a transmission path in which an error occurs.

  In the ARQ scheme, a transmission apparatus encodes packet data to be transmitted using a code having error detection capability and transmits the encoded packet data. The receiving apparatus detects an error of the received packet, and returns an acknowledgment ACK (ACKnowledgement) if the information is correct, and discards the received packet and returns a negative acknowledgment NAK (Negative AcKnowledgement) if the information is correct. The transmitter transmits the next packet when the ACK is returned, and retransmits the packet when the NAK is returned.

  When the receiving station receives the retransmission packet, it detects the error again and performs the same processing as when the initial transmission packet is received.

There are the following three methods for retransmission control of the ARQ method.
1) SAW (Stop And Wait) method In the SAW method, each time a transmitting device transmits one packet, it waits without transmitting the next packet until an ACK is returned. The transmission buffer is sufficient for one packet and is easy to control. However, round-trip transmission is required every time one packet is transmitted.
2) GBN (Go Back N) method The GBN method allows a maximum of N packets to be transmitted continuously without waiting for the return of an ACK for each packet. A serial number is assigned to the packet, and the serial number is confirmed between the transmitting and receiving apparatuses. This is generally called numbering control. In this method, the acknowledgment does not simply return ACK / NAK, but includes an acknowledgment of the packet transmitted from the previously returned ACK to that point by including the sequence number of the packet to be transmitted next. A single ACK can be returned in a batch. If an error is detected, the receiving apparatus sends a NAK including the serial number of the erroneous packet to the transmitting apparatus, thereby requesting retransmission of all packets after the serial number included in the NAK.
3) SR (Selective Repeat) method The SR method is a method of continuously transmitting up to N packets in the same way as the GBN method. ACK / NAK is performed by numbering control, but if an error is detected, only the erroneous packet is detected. Is different from the GBN method.

  FIG. 22 is an operation sequence of retransmission control according to the SAW method of the prior art. When transmitting packets P (1) to P (3) from the transmitting apparatus 100 to the receiving apparatus 200, the receiving apparatus 200 detects an error when receiving the second packet P (2), and the packet P (2 ) Shows the operation sequence when retransmitted. Here, “i” in the notation of the packet P (i) indicates the serial number of the packet.

  S01. Transmitting apparatus 100 transmits an initial packet P (1) to receiving apparatus 200 with an error detection code added.

  S02. The receiving apparatus 200 performs error detection using the error detection code included in the received packet P (1), and when there is no error, returns an acknowledgment ACK after a predetermined time T has elapsed. Here, the predetermined time T is the processing time of the receiving apparatus 200.

  S03. Receiving acknowledgment ACK for packet P (1) transmitted in sequence S01, transmitting apparatus 100 transmits next packet P (2) to receiving apparatus 200.

  S04. Since the receiving apparatus 200 detects an error in the received packet P (2), it returns a negative acknowledgment NAK after a predetermined time T has elapsed.

  S05. Since the transmission device 100 has received the negative acknowledgment NAK, the transmission device 100 retransmits the packet P (2) transmitted to the reception device 200 immediately before.

  S06. When the receiving apparatus 200 normally receives the retransmitted packet P (2), the receiving apparatus 200 returns an acknowledgment ACK after a predetermined time T has elapsed.

  S07. Upon receiving the acknowledgment ACK, the transmitting apparatus 100 transmits the next packet P (3).

  S08. When the received packet P (3) is normal, the receiving apparatus 200 returns an acknowledgment ACK after a predetermined time T has elapsed.

  FIG. 21 shows an operation sequence of retransmission control according to the conventional GBN method. When packets P (1) to P (7) are transmitted from the transmitting apparatus 100 to the receiving apparatus 200, the second packet P (2) is transmitted. Shows an operation sequence in the case where an error is detected and the packet P (2) and subsequent packets are retransmitted.

  S01. Transmitting apparatus 100 transmits an initial packet P (1) to receiving apparatus 200 with an error detection code added.

  S02. The transmitting apparatus 100 transmits the next packet P (2) without waiting for the response data from the receiving apparatus 200 to receive the packet P (1) transmitted in the sequence S01, and proceeds to the next sequence S04. To do.

  S03. On the other hand, the receiving device 200 detects an error in the received packet P (1), and returns a confirmation response ACK if it is normal.

  S04. Transmitting apparatus 100 transmits the next packet P (3) without waiting for reception of response data from receiving apparatus 200 for packet P (2) transmitted in sequence S02, and proceeds to sequence S06.

  S05. On the other hand, if an error is detected in the received packet P (2), the receiving apparatus 200 returns a negative acknowledgment NAK (2). Here, the number “2” in parentheses of NAK (2) indicates the serial number of the packet in which the error is detected.

  S06. The transmitting apparatus 100 transmits the next packet P (4) without waiting for reception of response data from the receiving apparatus 200 for the packet P (3) transmitted in the sequence S04, and proceeds to sequence S08.

  S07. On the other hand, receiving apparatus 200 receives packet P (3) transmitted from transmitting apparatus 100 in sequence S04, and returns an acknowledgment ACK when no error is detected.

  S08. When receiving the negative response NAK (2) returned from the receiving apparatus 200 in sequence S05, the transmitting apparatus 100 sequentially retransmits the packets having the serial numbers “2” and thereafter.

  S09. Receiving apparatus 200 receives packet P (4) transmitted in sequence S06, and returns an acknowledgment ACK if normal.

  S10. Following the sequence S08, the transmitting apparatus 100 retransmits the next packet P (3), and proceeds to the sequence S12. In other words, packet P (3) has already been transmitted in sequence S04, but since a negative response NAK (2) for packet P (2) with a lower sequence number was returned thereafter, the sequence numbers after packet P (2) are returned. The packet P (3) containing the message will also be retransmitted.

  S11. On the other hand, receiving apparatus 200 receives packet P (2) retransmitted in sequence S08, and returns an acknowledgment ACK when the error detection result is normal.

  After S12 to S19, the transmitting apparatus 100 continuously transmits the acknowledgment response ACK for the previously transmitted packet in a range of up to N without waiting for the receiving apparatus 200 to return the acknowledgment response ACK. On the other hand, if the error detection result of the received packet is normal, the receiving apparatus 200 returns an acknowledgment ACK.

  Although not shown in the operation sequence of retransmission control by the GBN method shown in FIG. 21 above, the response data is returned from the receiving device 200 to the transmitting device 100 after a predetermined time has passed, as in the SAW method.

  FIG. 20 shows an operation sequence of retransmission control by the SR method of the prior art. When packets P (1) to P (9) are transmitted from the transmission device 100 to the reception device 200, the second packet (2) is transmitted. An operation sequence in the case where an error is detected by the receiving apparatus 200 during transmission and only the packet P (2) is retransmitted is shown.

  S01. Transmitting apparatus 100 adds an error detection code to the first packet P (1) and transmits it to receiving apparatus 200.

  S02. Transmitting apparatus 100 transmits the next packet P (2) without waiting for reception of response data from receiving apparatus 200 with respect to packet P (1) transmitted in sequence S01, and then proceeds to sequence S04.

  S03. On the other hand, when receiving the packet P (1) normally, the receiving apparatus 200 returns an acknowledgment ACK.

  S04. Transmitting apparatus 100 transmits the next packet P (3) without waiting for reception of response data from receiving apparatus 200 for packet P (2) transmitted in sequence S02, and proceeds to sequence S06. .

  S05. On the other hand, the receiving apparatus 200 detects an error in the packet P (2) and returns a negative acknowledgment NAK (2). Here, the number “2” in parentheses of NAK (2) indicates the serial number of the packet in which an error is found.

  S06. The transmission apparatus 100 transmits the next packet P (4) without waiting for reception of response data from the reception apparatus 200 for the packet P (3) transmitted in the sequence S04, and proceeds to sequence S08. .

  S07. On the other hand, when receiving device 200 normally receives packet P (3) transmitted from transmitting device 100 in sequence S04, receiving device 200 returns an acknowledgment ACK.

  S08. Upon receiving the negative acknowledgment NAK (2) returned from the receiving apparatus 200 in sequence S05, the transmitting apparatus 100 retransmits the packet P (2) with the serial number “2” and proceeds to sequence S10.

  S09. On the other hand, receiving apparatus 200 receives packet P (4) transmitted in sequence S06, detects an error, and returns a confirmation response ACK if normal.

  S10. Transmitting apparatus 100 transmits packet P (5) of the next serial number after packet P (4) transmitted immediately before packet P (2) retransmitted in sequence S08.

  That is, in the GBN system shown in FIG. 21, the packets after the sequence number of the retransmitted packet are also retransmitted, whereas in this SR system, only the packet P (2) in which an error is detected is retransmitted. .

  S11. When receiving apparatus 200 normally receives packet P (2) retransmitted in sequence S08, it returns an acknowledgment ACK.

  From S12 to S19, the transmitting apparatus 100 continuously transmits the next packet in a maximum of N ranges without waiting for the acknowledgment ACK for the previously transmitted packet to be returned from the receiving apparatus 200. On the other hand, the receiving device 200 returns an acknowledgment ACK while the error detection result of the received packet is normal.

  Although omitted in the description of the operation sequence of the retransmission control by the SR method shown in FIG. 20, the response data is returned from the receiving device 200 to the transmitting device 100 after a predetermined time elapses as in the SAW method.

  In the three ARQ packet transmission methods described above, a packet having the same content as the initial transmission packet is retransmitted as a retransmission packet when an error occurs. A combination of this ARQ method and an error correction code is an H-ARQ (Hybrid-ARQ) method.

  In the H-ARQ scheme, when the packet received by the receiving apparatus can be successfully decoded by the error correction detection code, an acknowledgment ACK is returned to the transmitting apparatus, and the transmitting apparatus returns an ACK in the same manner as in the ARQ scheme. When received, the next packet is transmitted. When the packet received by the receiving device cannot be decoded normally by the error correction detection code, a negative acknowledgment NAK is returned, and when the transmitting device receives the NAK, the retransmission packet is transmitted. This is different from the ARQ system in that it is not necessarily the same as the initial transmission packet but may be different. In the following description of the H-ARQ scheme, the case of the SAW scheme in the ARQ scheme is taken as a representative example.

  There are three types of H-ARQ schemes, Type I, Type II, and Type III, depending on the error correction detection decoding method.

FIG. 19 shows a retransmission control method using the Type I H-ARQ scheme of the prior art.
S01. Transmitting apparatus 100 generates packet P including an error correction detection code and transmits it to receiving apparatus 200.

  S02. The receiving apparatus 200 decodes based on the error correction detection code included in the received packet P. If the decoding cannot be performed normally, a negative acknowledgment NAK is returned and a retransmission is requested to the transmitting apparatus 100.

  S03. The transmitting apparatus 100 that has received the negative response NAK retransmits the packet P having the same content as the packet transmitted in step S01.

  S04. The receiving apparatus 200 performs error correction detection decoding on the received packet P in the same manner as in step S02, and returns an acknowledgment ACK if it can be normally decoded.

  As described above, in the Type I H-ARQ scheme, the initial transmission packet and the retransmission packet have the same contents, and the error correction detection decoding process when the packet is received is independent of the initial transmission case and the retransmission case. Done.

  FIG. 18 shows a retransmission control method based on the Type II H-ARQ scheme of the prior art.

  S01. Transmitting apparatus 100 generates packet P including an error correction detection code and transmits it to receiving apparatus 200.

  S02. The receiving apparatus 200 stores the received packet P, and then performs error correction detection decoding on the packet P. If the decoding does not end normally, the receiving apparatus 200 returns a negative acknowledgment NAK and requests retransmission to the transmitting apparatus 100.

  S03. The transmitting apparatus 100 that has received the negative acknowledgment NAK retransmits the packet Pa composed of additional redundant bits for error correction detection.

  S04. The receiving apparatus 200 combines the packet P stored in step S02 and the retransmitted packet Pa composed of the redundant bits for error correction detection received this time, performs error correction detection decoding based on this, and decoding is normal. If completed, an acknowledgment ACK is returned.

  As described above, in the Type I H-ARQ scheme, a packet having the same content as that of the initial transmission is transmitted at the time of retransmission, whereas in the Type II H-ARQ scheme, the initial transmission packet is stored in the receiving apparatus. The apparatus only has to retransmit a retransmission packet consisting of only additional redundant bits, and can efficiently retransmit the packet when an error occurs. In addition, only a first packet is required for a transmission line with a low error rate, and error correction detection capability is enhanced by retransmission for a transmission line with a high error rate. Therefore, flexible retransmission adapted to the quality of the transmission line can be efficiently performed. Yes.

  FIG. 17 shows a retransmission control method based on the Type III H-ARQ scheme of the prior art.

  S01. Transmitting apparatus 100 generates packet P including an error correction detection code and transmits it to receiving apparatus 200.

  S02. The receiving apparatus 200 stores the received packet P and then decodes it based on the error correction detection code included in the packet P. If the decoding does not end normally, the receiving apparatus 200 returns a negative response NAK and returns it. Request a resend.

  S03. The transmitting apparatus 100 that has received the negative acknowledgment NAK retransmits the packet Pa including additional redundant bits for error correction detection.

  S04. First, the receiving apparatus 200 performs error correction detection decoding only on the received packet Pa, and returns a confirmation response ACK when decoding is normally performed.

  If decoding does not end normally, the packet P stored in step S02 and the packet Pa including redundant bits for error correction detection received this time are combined, and error correction detection is performed based on the combined data. Decryption is performed, and if the decryption is completed normally, an acknowledgment ACK is returned. That is, the Type III H-ARQ system is different from the Type II system in that the packet is configured so that it can be decoded only by the retransmitted packet Pa.

  FIG. 16 is an operation flowchart of retransmission control by the conventional ARQ method, and is an example of the retransmission control by the SAW method. In the operation flowchart of the transmission device 100 and the reception device 200, the relationship between the packet transmission / reception timings is indicated by dotted arrows.

  The transmission device 100 is activated by a packet transmission request from a higher-level device and operates in the next processing step.

  S01. A packet to be transmitted to the receiving apparatus 200 is generated.

  S02. An error detection code is added to the packet generated in step S01.

  S03. The packet is transmitted to the receiving apparatus 200. The packet transmitted here is accepted in step R01 of the receiving apparatus 200 described later, as indicated by a dotted arrow.

  S04. Waiting for reception of response data from the receiving apparatus 200 for the packet transmitted in step S03, and if received, the process proceeds to step S05.

  S05. It is determined whether the response data is a positive response ACK or a negative response NAK. If it is an acknowledgment ACK, the process proceeds to the next step S06, and if it is a negative response NAK, the process proceeds to step S07 for retransmission.

  S06. It is determined whether or not the packet transmitted in step S03 is the final packet. If it is not the final packet (NO), the process proceeds to step S01 to transmit the next packet, and if it is the final packet (YES) finish.

  S07. Generate a retransmission packet and proceed to step S02.

  The above is the operation flowchart of the transmitting apparatus 100.

  On the other hand, the receiving device 200 operates in the following steps in cooperation with the operation steps of the transmitting device 100 described above.

  R01. Waiting for reception of a packet transmitted from the transmitting apparatus 100, and when receiving a packet, the process proceeds to the next step R02.

R02. Error detection is performed using the error detection code included in the received packet.
R03. If there is no error and the signal is correctly received (YES), the process proceeds to the next step R04. If an error is detected (NO), the process proceeds to step R08.

  R04. In order to notify that the packet has been normally received, an acknowledgment ACK is set as response data.

  R05. The response data set in step R04 or step R08 described later is transmitted to the transmitting apparatus 100. The response data transmitted here is received in step S04 of the transmission device 100 as indicated by the dotted arrow.

  R06. It is determined whether or not the received packet is the last packet. If it is not the last packet (NO), the process proceeds to step R01 to receive the next packet. If it is the last packet (YES), the process proceeds to the next step R07. Transition.

  R07. The host device is notified that the last packet has been received correctly, and the process proceeds to step R01 to wait for the next packet reception.

  R08. Negative response NAK is set as response data, and the process proceeds to step R05.

  FIG. 15 is an operation flowchart of retransmission control according to the conventional H-ARQ scheme, and is an embodiment of retransmission control according to the Type II H-ARQ scheme. The relationship between packet transmission / reception timings of the transmission device 100 and the reception device 200 is indicated by dotted arrows.

  The transmission device 100 is activated by a packet transmission request from a higher-level device and operates in the next processing step.

  S01. A packet to be transmitted to the receiving apparatus 200 is generated.

  S02. The packet generated in step S01 is encoded with an error correction detection code.

  S03. The packet is transmitted to the receiving apparatus 200. The packet transmitted here is accepted in step R01 of the receiving apparatus 200 described later, as indicated by a dotted arrow.

  S04. Waiting for reception of response data from the receiving apparatus 200 for the packet transmitted in step S03, and if received, the process proceeds to step S05.

  S05. It is determined whether the response data is a positive response ACK or a negative response NAK. If it is an acknowledgment ACK, the process proceeds to the next step S06, and if it is a negative response NAK, the process proceeds to step S07 for retransmission.

  S06. It is determined whether or not the packet transmitted in step S03 is the final packet. If it is not the final packet (NO), the process proceeds to step S01 to transmit the next packet, and if it is the final packet (YES) And return to the host device that is the packet transmission request source.

  S07. Generate a retransmission packet including additional error correction detection code bits for the initial transmission packet generated in step S01, and proceed to step S02.

  The above is the operation flowchart of the transmitting apparatus 100.

  On the other hand, the receiving device 200 operates in the following steps in cooperation with the operation steps of the transmitting device 100 described above.

  R01. Wait for reception of a packet from the transmitting apparatus 100, and when receiving a packet, proceed to the next step R02.

  R02. Judge whether it is a retransmitted packet. If it is a retransmitted packet (YES), go to the next step R03 to combine, and if it is not a retransmitted packet, that is, if it is a first packet (NO), go to step R10. Transition.

  R03. The stored initial transmission packet and the retransmission packet received this time are combined, and the process proceeds to the next step R04.

  R04. Perform error correction detection decoding processing based on the delivered composite data. Thus, the error correction detection decoding capability can be enhanced by combining the initial transmission packet stored in step R10 described later and the additional redundant bit received this time to perform error correction detection decoding.

  R05. If the error correction detection / decoding is correctly performed (YES), the process proceeds to the next step R06. If the error correction detection / decoding is not correctly performed (NO), the process proceeds to step R11.

  R06. Affirmative acknowledgment ACK is set as response data, and it is transferred to the next step R07.

  R07. The response data set in step R06 or step R11 described later is transmitted to the transmitting apparatus 100. The response data transmitted here is accepted in step S04 of the transmitting device 100 as indicated by the dotted arrow.

  R08. Determine whether the received packet is the last packet or not. If it is the last packet (YES), go to the next step R07. If it is not the last packet (NO), go to step R01 to receive the next packet. To do.

  R09. The host device is notified that the last packet has been received correctly, and the process proceeds to step R01 to wait for the next packet reception.

  R10. Store the received packet and proceed to step R04. The packet data stored here is used for error correction detection decoding at the time of retransmission packet reception.

  R11. Negative response NAK is set as response data, and the process proceeds to step R07.

The retransmission control using the ARQ scheme and the H-ARQ scheme, which are the above-described conventional techniques, is disclosed in Non-Patent Document 1 below, for example.
Automatic repeat-request error control schemes; Lin, S., Costello, DJ; IEEE Communication Magazine, vol. 12, December 1984, pp. 5-17.

  In the conventional retransmission control process, in order to prevent transmission delay of a packet, response data is generally returned within a predetermined time for a packet transmitted by a transmission device. The amount of processing for error detection and correction performed in this way is limited by this predetermined time. For this reason, if error detection and correction processing is continued beyond a predetermined time, the packet can be corrected correctly. However, if the packet cannot be corrected correctly within the predetermined time, unnecessary retransmission is performed, resulting in transmission efficiency. There is a problem that falls.

  For example, in the case of a system using a turbo code, a packet cannot be correctly decoded when the number of repetitions of turbo decoding is 8 in the receiving apparatus, but this is the case when a packet can be correctly decoded with 16 repetitions. As another example, in retransmission control based on the Type III H-ARQ scheme, when the receiving apparatus cannot perform error correction detection decoding correctly only with the initial transmission packet and makes a retransmission request, the initial transmission packet and the retransmission packet are combined. In this case, the correctness cannot be determined.

In the retransmission control method when transmitting a packet from a transmission device to a reception device, the present invention further continues error detection correction processing even if the packet received by the reception device cannot be detected and corrected within a predetermined time. by performing, and to provide an efficient retransmission control how you and receiving apparatus capable of suppressing the number of packet retransmissions.

According to a first aspect of the present invention, there is provided a receiving apparatus that performs retransmission control on a coded packet transmitted from a transmitting apparatus, and performs a first error detection correction process on the packet; Means for performing a second error detection correction process, and when the error is eliminated within a predetermined time in the first error detection correction process for the received packet, the second error detection correction process is not executed. And a means for returning an acknowledgment requesting the next packet, and a negative response requesting a retransmission packet if the error is not resolved within a predetermined time by the first error detection correction process for the received packet. When the second error detection correction process is executed on the packet after the first error detection correction process and the error is eliminated by the second error detection correction process, It means for returning an acknowledgment requesting packet, and configured to include.

According to the first invention, if the error is not resolved even after the first error detection and correction processing of the received packet is performed for a predetermined time, the receiving device returns a negative response to the transmitting device and resends the packet. after requesting performs second error detection correction process subsequently by returning an acknowledgment when an error is eliminated in the second error detection compensation processing, the transmitting device, once receiving a negative acknowledgment However, if the affirmative response is returned when the retransmission packet transmission process is not started for some reason, transmission of the retransmission packet can be canceled, and transmission of unnecessary retransmission packets can be suppressed. In general, a transmitting device transmits packets to a plurality of receiving devices at the same time. Even if a negative response is received, a retransmission process may be awaited while processing a packet transmission for another receiving device. By suppressing the transmission of retransmission packets in such a situation, it is possible to improve packet transmission efficiency.

  According to a second aspect, in the retransmission control method according to the first aspect, the receiving device returns an acknowledgment when receiving the retransmission packet, if an error of the previously received packet is eliminated. is doing.

  According to the second aspect of the present invention, if the receiving apparatus can correct the error of the initial transmission packet after returning the negative response once, the retransmission is unconditionally returned to the retransmission packet. Even if the packet itself is wrong, it is possible to avoid the retransmission of the retransmission packet, and to improve the packet transmission efficiency.

  As a mode of realization of the above invention, the transmission apparatus can be configured to transmit the packet after turbo encoding, and the reception apparatus can perform error detection correction by repeatedly performing turbo decoding.

  Further, the receiving apparatus may be configured to perform error detection correction by passing an interference canceller once or more to remove an interference signal when demodulating a received packet.

  Further, the initial transmission packet and one or more retransmission packets may be held in the receiving apparatus, and the result of combining and combining them may be detected and corrected.

  In the present invention, when error detection correction is performed on an encoded packet transmitted from a transmission apparatus to a reception apparatus, the transmission apparatus first uses the result of the first error detection correction performed within a predetermined time as an affirmative response or negative response. When a negative response is returned, the second error detection correction is subsequently performed, and when the error is resolved, an acknowledgment is returned. Is transmitted, but is not retransmitted when an acknowledgment is received by the start of retransmission packet transmission.

  As a result, even if the transmission device has once received a negative response, it can cancel the transmission of the retransmission packet if an acknowledgment is returned at the time when the transmission processing of the retransmission packet is not started for some reason. And transmission of unnecessary retransmission packets can be suppressed. In general, a transmitting device transmits packets to a plurality of receiving devices at the same time. Even if a negative response is received, a retransmission process may be awaited while processing a packet transmission for another receiving device. By suppressing the transmission of retransmission packets in such a situation, efficient packet transmission is possible.

  In addition, the receiving apparatus is configured to return an acknowledgment regardless of whether there is an error in the retransmission packet if the second error detection correction processing is completed by the time when the retransmission packet is received.

  As a result, even if an error is detected in the retransmission packet itself, if the error of the initial transmission packet is eliminated by the second error detection correction process, the retransmission packet can be prevented from being transmitted again, and the transmission can be efficiently performed. Retransmission control can be performed.

  FIG. 1 shows an operation sequence (1) of retransmission control according to the present invention.

  When the packet received by the receiving device 200 cannot be completed within a predetermined time, and the error detection and correction can be correctly corrected without performing retransmission by continuing the processing thereafter. An example is shown.

  S01. Transmitting apparatus 100 transmits encoded first packet P (1) to receiving apparatus 200.

  S02. The receiving apparatus 200 performs error detection and correction on the received packet P (1), and returns a positive response ACK when correct correction is performed.

  S03. Upon receiving the acknowledgment ACK from the receiving apparatus 200, the transmitting apparatus 100 transmits the next second packet P (2), and then proceeds to sequence S06.

  S04. On the other hand, the receiving apparatus 200 corrects and corrects an error in the received packet P (2), but cannot correct it correctly within a predetermined time, and after returning a negative response NAK at that time, continues to the next Sequence S05 is executed.

  S05. The receiving apparatus 200 transmits an acknowledgment ACK to the transmitting apparatus 100 when it can be corrected correctly as a result of continuing the error detection correction process following the sequence S04.

  S06. If the transmission device 100 has not started retransmission processing for the NAK returned from the reception device 200 in sequence S04 because the processing is congested due to transmission processing to other reception devices other than the reception device 200, for example. Then, the acknowledgment ACK is accepted without performing the retransmission process, and the next third packet P (3) is transmitted.

  S07. The receiving apparatus 200 receives the packet P (3), performs error detection correction, and returns a positive response ACK when the correction is correct.

  From S08 to S13., The transmitting apparatus 100 sequentially transmits the next encoded packet while waiting for the reception of the acknowledgment ACK from the receiving apparatus 200, and the receiving apparatus 200 sequentially detects the received packet for error detection correction. If correct correction is possible, an acknowledgment ACK is returned.

  In the embodiment of FIG. 1 described above, the transmitting device 100 receives the acknowledgment ACK after starting the retransmission processing of the packet P (2) after receiving the NAK from the receiving device 200. The next packet P (3) can be transmitted without performing retransmission. Thus, it can be seen that efficient transmission is performed without retransmission, as compared with the operation sequence of retransmission control by the SAW method of the prior art shown in FIG.

  FIG. 2 is an operation sequence (2) of retransmission control according to the present invention.

  Unlike the embodiment shown in FIG. 1, the transmitting apparatus 100 shows a case where an acknowledgment ACK is received after starting a retransmission process of the packet P (2) after receiving a NAK from the receiving apparatus 200.

  S01. Transmitting apparatus 100 transmits encoded first packet P (1) to receiving apparatus 200.

  S02. The receiving apparatus 200 performs error detection and correction on the received packet P (1), and returns a positive response ACK when correct correction is performed.

  S03. When receiving the acknowledgment ACK from the receiving device 200, the transmitting device 100 transmits the next second packet P (2).

  S04. Receiving apparatus 200 corrects and detects an error in received packet P (2), but cannot correct it correctly within a predetermined time. At that time, negative response NAK is returned, and error correction processing is continued in sequence S06. Do.

  S05. On the other hand, since the transmission device 100 has received the negative acknowledgment NAK from the reception device 200, the transmission device 100 generates and transmits a retransmission packet Pa (2) based on the initial transmission packet P (2) transmitted in the sequence S03.

  S06. Following the sequence S04, the receiving apparatus 200 can correct correctly as a result of continuing the error detection correction process, and returns an acknowledgment ACK to the transmitting apparatus 100 at that time. However, since transmission apparatus 100 has already started retransmission processing for the NAK returned in sequence S04, retransmission of packet Pa (2) cannot be suppressed in this case.

  S07. The receiving apparatus 200 receives the retransmission packet Pa (2) transmitted from the transmitting apparatus 100 in the sequence S05, but since the error detection correction of the initial transmission packet has been completed at that time, the received retransmission packet An acknowledgment ACK is returned regardless of whether the packet is correct or not.

  S08. The transmitting apparatus 100 accepts the acknowledgment ACK from the receiving apparatus 200 and transmits the next third packet P (3).

  S09. The receiving apparatus 200 receives the packet P (3), and returns an acknowledgment ACK when the error detection correction is correctly performed.

  From S10 to S13., The transmitting apparatus 100 sequentially transmits the next encoded packet while waiting for the reception of the acknowledgment ACK from the receiving apparatus 200, and the receiving apparatus 200 sequentially detects the received packet for error detection correction. If correct correction is possible, an acknowledgment ACK is returned.

  In the embodiment of FIG. 2 described above, since the ACK transmission after the NAK transmission from the receiving device 200 is received after the transmitting device 100 starts the retransmission process of the packet Pa (2), the transmitting device 100 receives the packet Pa (2). However, for this retransmission packet, since error detection correction has already been completed by the initial transmission packet, an acknowledgment ACK is returned regardless of whether there is an error in the retransmission packet, Comparing with the operation sequence of the retransmission control by the SAW system of the prior art shown in FIG.

  FIG. 3 shows a case where a transmission error occurs in the retransmission packet shown in FIG. 2 in the retransmission control operation sequence (3) of the present invention. In the receiving device 200, since the error correction processing of the initial transmission packet has been completed, even when a transmission error occurs in the retransmission packet, an acknowledgment ACK is returned, and it is not necessary to transmit the retransmission packet again. It can be seen that more efficient packet transmission is performed as compared with the operation sequence of retransmission control according to the conventional SAW method. Since the processing steps in FIG. 3 are the same as the processing steps in FIG. 2, detailed description thereof is omitted.

  FIG. 4 is an operation sequence (4) of retransmission control according to the present invention.

  When transmitting packets P (1) to P (3) from the transmitting apparatus 100 to the receiving apparatus 200, the receiving apparatus 200 detects an error when receiving the second packet P (2), and the packet P (2 ) Is described in relation to a predetermined time when response data is returned from the receiving apparatus to the transmitting apparatus.

  S01. Transmitting apparatus 100 encodes first packet P (1) and transmits it to receiving apparatus 200.

  S02. The receiving apparatus 200 corrects and detects an error in the received packet P (1), and immediately returns an acknowledgment ACK when it is corrected correctly.

  S03. Upon receiving an acknowledgment ACK for packet P (1) transmitted in sequence S01, transmitting apparatus 100 transmits next packet P (2) to receiving apparatus 200.

  S04. The receiving apparatus 200 starts error detection correction processing immediately after receiving the packet P (2), but returns a negative response NAK when correct correction is not possible even after a predetermined time T has elapsed.

  S05. Since the transmission device 100 has received the negative acknowledgment NAK, the transmission device 100 transmits the retransmission packet Pa (2) generated based on the packet P (2) transmitted to the reception device 200 immediately before.

  S06. When receiving apparatus 200 has correctly detected and corrected retransmission packet Pa (2), it immediately returns an acknowledgment ACK.

  S07. Upon receiving the acknowledgment ACK, the transmitting apparatus 100 transmits the next packet P (3).

  S08. When the receiving device 200 has correctly detected and corrected the received packet P (3), it immediately returns an acknowledgment ACK.

  According to the retransmission control operation sequence (4) of the present invention shown in FIG. 4 above, when a packet is correctly received on the receiving apparatus side, the retransmission control operation using the conventional SAW method shown in FIG. Since the acknowledgment ACK is returned without waiting for the elapse of the predetermined time T as in the sequence, the transmitting apparatus can also transmit the next packet earlier by that amount, and more efficient packet transmission can be performed.

  FIG. 5 is a flowchart (1) of retransmission control according to the present invention, and shows the relationship between transmission / reception timings of the transmission device 100 and the reception device 200 in association with dotted arrows.

  The transmission device 100 is activated by a packet transmission request from a higher-level device and operates in the next processing step.

  S01. Based on the data delivered from the host device, a packet to be transmitted to the receiving device 200 is generated.

  S02. Encode the packet generated in step S01.

  S03. The packet encoded in step S02 is transmitted to receiving apparatus 200. The packet transmitted here is accepted in step R01 of the receiving apparatus 200 described later, as indicated by a dotted arrow.

  S04. Waiting for reception of response data from the receiving apparatus 200, and when receiving response data, the process proceeds to the next step S05.

  S05. It is determined whether the received response data is an acknowledgment ACK or a negative acknowledgment NAK, and if it is an acknowledgment ACK (ACK), the process proceeds to the next step S06, and if it is a negative acknowledgment NAK (NAK), for retransmission processing Control goes to step S07.

  S06. It is determined whether or not the packet transmitted in step S03 is the final packet. If the packet is the final packet (YES), the host device is notified and the process is terminated. The process proceeds to step S01.

  S07. Based on the initial transmission packet generated in step S01, a retransmission packet is generated, and the process proceeds to step S02.

  The above is the processing steps of the transmitting apparatus 100.

  On the other hand, the receiving device 200 is activated by a request from the host device, and operates in the next processing step in cooperation with the transmitting device 100.

  R01. Wait for reception of a packet from the transmitting apparatus 100, and when receiving a packet, proceed to the next step R02.

  R02. It is determined whether or not the received packet is a retransmission packet. If the packet is a retransmission packet (YES), the process proceeds to the next step R03. If the packet is not a retransmission packet (NO), the process proceeds to step R04.

  R03. When the retransmission packet is received in step R02, the error detection correction processing 2a shown in FIG. 7 described later is performed in order to stop the second error detection correction processing started and executed in step R09 described later. Stop.

  R04. First error detection correction processing is performed. Here, the error detection and correction processing of the received packet is repeated within a predetermined time until it is correctly completed.

  R05. If the error detection / correction is correctly performed in step R04, the process proceeds to the next step R06 after a predetermined time elapses, and an acknowledgment ACK is returned. If the error correction cannot be corrected correctly by the lapse of a predetermined time even after repeating the error detection correction, the process proceeds to step R08 in order to return the NAK and continue the error detection correction process.

  Here, if the transmitting device 100 is capable of accepting a response before a predetermined time, if the error detection / correction can be correctly performed, the process immediately proceeds to step R06 and an acknowledgment ACK may be returned. In this case, an acknowledgment is returned to the transmitting device 100 before a predetermined time elapses, and the transmitting device 100 can quickly transmit the next packet, thereby enabling efficient packet transmission.

  R06. In order to notify that the packet has been normally received, an acknowledgment ACK is returned to the transmitting apparatus 100. The acknowledgment ACK returned here is accepted in step S04 of the transmitting apparatus 100 as indicated by a dotted arrow.

  R07. Notify the received packet to the host device, move to step R01 and wait for the next packet reception.

  R08. In order to request retransmission of the packet, a negative acknowledgment NAK is returned to the transmitting apparatus 100. The negative response NAK returned here is accepted in step S04 of the transmitting apparatus 100 as indicated by the dotted arrow.

  R09. In order to perform the second error detection correction process, an error detection correction process 2a shown in FIG. 7 to be described later is started as a separate process capable of performing parallel processing, and then a step R01 is performed to wait for reception of the next packet. Migrate to Here, by starting the error detection correction processing 2a as a separate process, the second error detection correction processing is executed in parallel even during the packet reception waiting state.

  FIG. 6 is an operation flowchart (2) of the retransmission control according to the present invention. Compared with the operation flowchart shown in FIG. 5, the second error detection and correction process instructed to start and stop by the receiving apparatus 200 is performed. The only difference is that the process is changed from the error detection correction processing 2a to the error detection correction processing 2b. As shown in FIG. 7 to be described later, in the error detection correction process 2a, when the error detection correction is correctly completed, an acknowledgment ACK is returned. However, in the error detection correction process 2b, the acknowledgment ACK is returned even when the error detection correction is correctly completed. The point is different.

  Details of the processing of the transmission apparatus 100 are the same as those of the transmission apparatus 100 shown in FIG.

  The receiving device 200 is activated in response to a request from the host device, and operates in the next processing step in cooperation with the transmitting device 100.

  R01. Waiting for reception of a packet transmitted from the transmitting apparatus 100, and when receiving a packet, the process proceeds to the next step R02.

  R02. It is determined whether or not the received packet is a retransmission packet. If the packet is a retransmission packet (YES), the process proceeds to the next step R03. If the packet is not a retransmission packet (NO), the process proceeds to step R04.

  R03. When a retransmission packet is received in step R02, the error detection correction 2b process shown in FIG. 7 to be described later is stopped in order to stop the second error detection correction processing that is started and executed in step R09 to be described later. To do.

  R04. First error detection correction processing is performed. Here, the error detection and correction processing of the received packet is repeated within a predetermined time until it is correctly completed.

  R05. If the error detection / correction is correctly performed in step R04, the process proceeds to the next step R06 after a predetermined time elapses, and an acknowledgment ACK is returned. If the error correction cannot be corrected correctly by the lapse of a predetermined time even after repeating the error detection correction, the process proceeds to step R08 in order to return the NAK and continue the error detection correction process.

  Here, if the transmitting device 100 is capable of accepting a response before a predetermined time, if the error detection / correction can be correctly performed, the process immediately proceeds to step R06 and an acknowledgment ACK may be returned. In this case, an acknowledgment is returned to the transmitting device 100 before a predetermined time elapses, and the transmitting device 100 can quickly transmit the next packet, thereby enabling efficient packet transmission.

  R06. In order to notify that the packet has been normally received, an acknowledgment ACK is returned to the transmitting apparatus 100. The acknowledgment ACK returned here is accepted in step S04 of the transmitting apparatus 100 as indicated by a dotted arrow.

  R07. The received packet is notified to the host device, and the process proceeds to step R01 to wait for the next packet reception.

  R08. In order to request retransmission of the packet, a negative acknowledgment NAK is returned to the transmitting apparatus 100. The negative response NAK returned here is accepted in step S04 of the transmitting apparatus 100 as indicated by the dotted arrow.

  R09. After returning NAK in step R09, in order to perform the second error detection correction process, error detection correction process 2b shown in FIG. To wait for reception, the process proceeds to step R01. Here, by starting the error detection correction process 2b as a separate process, the second error detection correction process is executed in parallel even while waiting for reception of a packet.

  FIG. 7 is an operation flowchart (3) of retransmission control according to the present invention. The error detection correction process 2a started from the receiving apparatus 200 shown in FIG. 5 and the receiving apparatus 200 shown in FIG. The processing contents of the error detection correction processing 2b are shown.

  The error detection / correction processing 2a is started as a separate process from step R09 of the receiving apparatus 200 shown in FIG. 5, and performs processing according to the following procedure.

  R21. Performs error detection correction processing on the transferred packet data.

  R22. It is determined whether or not the error detection correction process of step R21 has been completed correctly. If the error detection correction is correctly performed (YES), the process proceeds to the next step R23, and the error detection correction is not correctly performed. If (NO), the process returns to step R21 to repeat the error detection and correction process. If the error detection / correction process is not completed normally and the error detection / correction process is repeated, the process is stopped when the retransmission packet is received as shown in step R03 of the receiving apparatus 200 in FIG.

  R23. Memorize that the error detection correction is completed.

  R24. An acknowledgment ACK is returned to the transmitting apparatus 100, and the process is terminated. The acknowledgment ACK transmitted here is accepted in step S04 of the transmitting apparatus 100 in FIG. 5, as indicated by the dotted arrow in FIG. As a result, even if the initial transmission packet is error-detected and corrected for a predetermined time, the error is not eliminated and the negative acknowledgment NAK is returned once. Then, when the error detection correction is completed, an acknowledgment ACK is immediately returned, and the transmitting device 100 However, if retransmission processing has not started yet, transmission of retransmission packets can be suppressed, and efficient retransmission control can be performed.

  The error detection / correction processing 2b is started as a separate process from step R09 of the receiving apparatus 200 shown in FIG. 6, and performs processing according to the following procedure.

  R31. Perform error detection and correction processing on the transferred packet data.

  R32. Judges whether or not the error detection correction process of step R31 has been completed correctly, and if error detection correction is correctly performed (YES), moves to the next step R33, and error detection correction was not performed correctly If (NO), the process returns to step R31 to repeat the error detection correction process. If the error detection and correction process is not completed normally and this error detection and correction process is repeated, the process is stopped when the retransmission packet is received as shown in step R03 of the receiving apparatus 200 in FIG.

  R33. The fact that the error detection correction has been completed is stored, and the process is terminated.

  As described above, the error detection correction process 2b differs from the error detection correction process 2a described above in that the acknowledgment ACK is not returned even when the error detection correction is correctly completed. According to this, even if the acknowledgment ACK is not returned, even if the received retransmission packet itself has an error, the acknowledgment ACK is surely returned, and the retransmission due to the error of the retransmission packet can be suppressed. Increase efficiency.

  FIG. 8 shows the configuration of the transmission apparatus according to the present invention.

  The packet generation unit 101 decomposes the transmission data delivered from the host device into packets, delivers the packets to the data selection unit 104 for each packet, and simultaneously stores the packets in the storage unit 102 for retransmission due to a transmission error or the like. Keep it.

  When the data selection unit 104 passes the packet delivered from the packet generation unit 101 to the encoding unit 105, the encoding unit 106 encodes the packet and then passes the packet to the modulation unit 106. The packet is modulated by the modulation unit 106 and then transmitted to the reception apparatus 200 by the transmission unit 107.

  In response to the packet transmitted from the transmitting unit 107 to the receiving device 200, response data (ACK or NAK) returned from the receiving device 200 is received by the receiving unit 108, demodulated by the demodulating unit 109, and then responded. The signal analysis unit 110 analyzes the content, and the analysis result is notified to the data selection unit 104.

  When “ACK” is notified from the response signal analysis unit 110, the data selection unit 104 requests the packet generation unit to deliver the next packet. When the response signal analysis unit 110 receives “NAK” Asks the retransmission packet generation unit 103 to deliver the retransmission packet. Here, retransmission packet generation section 103 generates a retransmission packet based on the packet data stored in storage section 102 and delivers it to data selection section 104.

  The data selection unit 104 uses the encoding unit 105, the modulation unit 106, and the transmission unit 107 for the retransmission packet delivered from the retransmission packet generation unit 103 in the same manner as the initial transmission packet delivered from the packet generation unit 101. To the receiving device 200.

  Here, when the process of the retransmission packet generation unit 103 is delayed for some reason and the delivery timing of the retransmission packet to the data selection unit 104 is delayed, the second error detection correction performed by the receiving apparatus 200 is correctly performed. If ACK is returned as a result, the ACK is preferentially processed and the packet retransmission process is stopped. This makes it unnecessary, for example, when a packet is being transmitted from the same transmitter to a plurality of receivers at the same time, and retransmission processing is delayed due to packet transmission processing to other receivers. Transmission of retransmission packets can be suppressed.

  FIG. 9 shows a configuration of a receiving apparatus according to the present invention.

  The packet transmitted from the transmitting apparatus 100 is received by the receiving unit 210, demodulated by the demodulating unit 220, and then delivered to the data selecting unit 230.

  The data selection unit 230 delivers the packet to the error detection correction unit 240 and simultaneously instructs the error detection determination unit 250 to start error detection determination processing.

  The error detection determination unit 250 instructs the error detection correction unit 240 to start the first error detection correction process for the delivered packet, and simultaneously starts a monitoring timer for a predetermined time T.

  The error detection / correction unit 240 repeatedly executes error detection / correction processing for the packet, and notifies the error detection determination unit 250 of the processing result each time. Then, when a stop instruction is received from the error detection determination unit 250, the process is stopped.

  When the error detection determination unit 250 receives a notification from the error detection correction unit 240 that the error detection correction has been correctly completed, the error detection determination unit 250 notifies the response signal generation unit 260 to request transmission of an acknowledgment ACK, and at the same time, The correction unit 240 is instructed to stop processing. The monitoring timer for a predetermined time T is also stopped, and the received packet is delivered to the host device.

  Even when the predetermined time T has elapsed, if the error detection / correction unit 240 does not notify that the error detection / correction has been correctly completed, the response signal generation unit 260 is requested to transmit a negative response NAK. Here, since there is no instruction to stop processing from the error detection determination unit 250, the error detection correction unit 240 performs the second error detection correction process. When the error detection correction is correctly performed, the error detection determination unit 250 requests the response signal generation unit 260 to transmit an acknowledgment ACK, and at the same time, instructs the error detection correction unit 240 to stop processing to detect the error. The fact that the correction is correctly completed is stored. As a result, even if NAK is returned in the result of the first error detection correction process, an ACK is immediately returned if the error detection correction can be correctly performed in the subsequent second error detection correction process. When an ACK is received by the transmission device at the time when retransmission processing has not yet started, retransmission processing is suppressed and efficient retransmission control is performed.

  The above-described second error detection correction process is repeatedly executed when the error detection correction is not completed correctly. Then, when the data selection unit 230 detects the reception of the retransmission packet, the error detection determination unit 250 is notified to that effect, and the error detection determination unit 250 stops by instructing the error detection correction unit 240 to stop processing. Is done.

  The response signal generation unit 260 generates an acknowledgment ACK or negative response NAK in response to a request from the error detection determination unit 250, modulates the modulation by the modulation unit 270, and then transmits to the transmission device 100 via the transmission unit 280. Send.

  For the retransmitted packet, error detection correction processing is performed in the same manner as described above. However, when the error detection correction is correctly completed by the second error detection correction processing at the time of retransmission packet reception, an error detection determination unit 250 requests the response signal generation unit 260 to transmit an acknowledgment ACK regardless of the error detection correction result of the retransmission packet itself. As a result, even if the retransmission packet itself is incorrect, the retransmission process again becomes unnecessary, and an efficient retransmission process is performed.

  In addition, in the second error detection correction process described above, when the error detection correction is correctly completed, the error detection determination unit 250 does not request the response signal generation unit 260 to transmit an acknowledgment ACK, and the error detection correction is performed. It may be configured to instruct the error detection / correction unit 240 to stop processing after storing the fact that it has been correctly completed. In this case, the retransmission process itself of the transmission device cannot be suppressed, but an acknowledgment ACK is surely returned regardless of whether there is an error in the retransmission packet itself, and even if the retransmission packet is incorrect, the retransmission process is suppressed again. it can.

  FIG. 10 shows the configuration of the error detection and correction unit when turbo codes are used for packet encoding in the configuration (1) of the error detection and correction unit according to the present invention.

The first error detection and correction process is performed on the packet delivered from the data selection unit 230 as follows. The turbo decoding unit 241a performs turbo decoding processing on the passed packet, notifies the error detection determination unit 250 of the result, and simultaneously feeds back to the input of the turbo decoding unit 241a to repeat decoding processing, thereby improving the accuracy of error detection correction. The error detection and correction process is continued while raising the value. This iterative process is continued until a stop signal STP is input from the error detection determination unit 250.

  In this case, the error detection unit 250 notifies the turbo decoding unit 241a of the stop signal STP when the turbo decoding unit 241a notifies the turbo decoding unit 241a of the normal decoding, and simultaneously requests the response signal generation unit 260 to confirm A response ACK is returned to the transmitting apparatus 100.

  In the first error detection correction process, when the packet is not correctly decoded even after the predetermined time T has elapsed, the response signal generation unit 260 is requested to return a negative response NAK to the transmission device 100. The second error detection correction process is performed by repeating the above decoding process until a retransmitted packet is received, and at the time when decoding is correctly performed, the error detection determination unit 250 issues a stop instruction STP to the turbo decoding unit 241a. At the same time, the response signal generator 260 is requested to transmit an acknowledgment ACK to the transmitter 100.

  The error detection determination unit 250 instructs the turbo decoding unit 241a to stop the decoding process when the data selection unit 230 notifies the reception of the retransmission packet.

  The error detection unit 250 may be configured not to make a request for returning an acknowledgment ACK even when the second error detection correction process is correctly decoded.

  The turbo decoding process performs error correction detection decoding of a plurality of patterns, and the first error detection correction process and the second error detection correction process are configured to change the execution order of these patterns. Is also possible.

  FIG. 11 shows the configuration (2) of the error detection / correction unit according to the present invention, which holds an initial transmission packet and one or more retransmission packets and performs error detection correction by combining them. The embodiment of FIG. 11 shows a configuration in which error correction detection decoding is performed by combining an initial transmission packet and two types of retransmission packets generated therefrom. Further, an error correction detection code is used for encoding, and the receiving apparatus performs error correction detection decoding processing as error detection correction processing.

  The packet storage unit 244b, the retransmission packet 1 storage unit 245b, and the retransmission packet 2 storage unit 246b are storage areas for storing the initial transmission packet, the first retransmission packet, and the second retransmission packet, respectively.

  The selection control unit 241b selects which of the packet storage unit 244b, the retransmission packet 1 storage unit 245b, and the retransmission packet 2 storage unit 246b is to be subjected to error correction detection decoding processing, and then selects the combination unit 242b. Instructs synthesis of packet data.

  The combining unit 242b combines the packets in the storage area designated by the selection control unit 241b, and then transfers them to the error correction detection decoding processing unit 243b. The error correction detection decoding processing unit 243b performs error correction detection decoding on the transferred packet data. The result is notified to the selection control unit 241b and the error detection determination unit 250.

  As an embodiment according to this configuration, when the initial transmission packet, the first retransmission packet, and the second retransmission packet are received, the difference between the processing contents of the respective first error detection correction processes, Embodiments are possible.

  In the first embodiment, the error correction detection decoding process for the packet received immediately before is the first error detection correction process.

  First, in the case of initial transmission packet reception, the selection control unit 241b selects only the packet storage unit 244b and instructs the combining unit 242b, and the error correction detection decoding processing unit 243b performs error correction detection decoding of only the initial transmission packet in a predetermined By performing it within the time, the first error detection correction process is performed. The processing result of the error correction detection decoding processing unit 243b is notified to the error detection determination unit 250. When the error correction detection decoding is performed correctly, an acknowledgment ACK is received. When the error correction detection decoding is not performed correctly The negative acknowledgment NAK is returned to the transmitting device 100, respectively.

  When the first retransmission packet is transmitted from the transmitting device 100 in response to the NAK return, the selection control unit 241b selects only the retransmission packet 1 storage unit 245b and instructs the combining unit 242b to generate an error. The correction detection decoding processing unit 243b performs the first error detection correction processing by performing error correction detection decoding of the first retransmission packet within a predetermined time. The processing result of the error correction detection decoding processing unit 243b is notified to the error detection determination unit 250. When the error correction detection decoding is performed correctly, an acknowledgment ACK is received. When the error correction detection decoding is not performed correctly, negative processing is performed. The response NAK is returned to the transmitting device 100, respectively. If the first error detection correction process is not completed correctly, then the selection control unit 241b selects the packet storage unit 244b and the retransmission packet 1 storage unit 245b and instructs the combining unit 242b to generate an error. The correction detection decoding processing unit 243b performs error correction detection decoding on the result of combining the initial transmission packet and the first retransmission packet, thereby performing the second error detection correction processing. The processing result of the error correction detection decoding processing unit 243b is notified to the error detection determination unit 250, and an acknowledgment ACK is returned to the transmission device 100 only when error correction detection decoding is correctly performed.

  When the first error detection correction process is not completed correctly and the second retransmission packet is transmitted from the transmission device 100, and the second error detection correction process is not completed correctly The selection control unit 241b selects only the retransmission packet 2 storage unit 245b and instructs the combining unit 242b, and the error correction detection decoding processing unit 243b performs error correction detection decoding of the second retransmission packet within a predetermined time. Thus, the first error detection and correction process is performed. Then, the processing result of the error correction detection decoding processing unit 243b is notified to the error detection determination unit 250, and when the error correction detection decoding is performed correctly, an acknowledgment ACK is received, and when the error correction detection decoding is not performed correctly The negative response NAK is returned to the transmitting device 100, respectively. If the first error detection correction process is not completed correctly, the second error detection correction process is performed in the following procedure.

  The selection control unit 241b selects the packet storage unit 244b and the retransmission packet 2 storage unit 246b and instructs the combining unit 242b, and the error correction detection decoding processing unit 243b combines the initial transmission packet and the second retransmission packet. Error correction detection decoding is performed on the result, and the processing result is notified to the error detection determination unit 250. Here, only when the error correction detection decoding is correctly performed, an acknowledgment ACK is transmitted to the transmitting apparatus 100. However, when the error correction detection decoding is not completed correctly, the selection control unit 241b receives the packet storage unit 244b, The packet 1 storage unit 245b and the retransmission packet 2 storage unit 246b are selected and instructed to the combining unit 242b, and the error correction detection decoding processing unit 243b performs the initial transmission packet, the first retransmission packet, and the second retransmission. Error correction detection decoding is performed on the result of combining the packets, and the processing result is notified to the error detection determination unit 250. Here, an acknowledgment ACK is transmitted to transmitting apparatus 100 only when error correction detection / decoding is correctly performed. The above is the second error detection correction process.

  The second embodiment for realizing the configuration shown in FIG. 11 is a method for performing a first error detection correction process by performing error correction detection decoding on a combination of all packet data currently held. It is.

  First, in the case of initial transmission packet reception, the selection control unit 241b selects only the packet storage unit 244b and instructs the synthesis unit 242b, and the error correction detection decoding processing unit 243b stores the initial transmission packet stored in the packet storage unit 244b. The first error detection correction process is performed by performing error correction detection decoding in a predetermined time. The processing result of the error correction detection decoding processing unit 243b is notified to the error detection determination unit 250. When the error correction detection decoding is performed correctly, an acknowledgment ACK is received. When the error correction detection decoding is not performed correctly, negative processing is performed. The response NAK is returned to the transmitting device 100, respectively. The second error detection correction process is not performed for this initial transmission packet reception.

When the first retransmission packet is transmitted from the transmission device 100 to the NAK that has been returned because the first error detection correction process has not been performed correctly, the selection control unit 241b performs the packet storage unit 244b and the retransmission. The packet 1 storage unit 245b is selected and instructed to the combining unit 242b, and the error correction detection decoding processing unit 243b performs error correction detection decoding within a predetermined time on the result of combining the initial transmission packet and the first retransmission packet. To perform the first error detection correction process. The processing result of the error correction detection decoding processing unit 243b is notified to the error detection determination unit 250, and when the error correction detection decoding process is correctly performed, an acknowledgment ACK is received. When the error correction detection decoding process is not performed correctly, a negative response is received. The NAK is returned to the transmitting device 100. When the error correction detection decoding process is not performed correctly, the selection control unit 241b selects the retransmission packet 1 storage unit 245b and combines
The error correction detection decoding processing unit 243b performs the second error detection correction processing by performing error correction detection decoding of the first retransmission packet. The processing result of the error correction detection decoding processing unit 243b is notified to the error detection determination unit 250, and ACK is returned to the transmission device only when the error correction detection decoding is correctly performed.

  If the first error detection correction process is not completed correctly and a NAK is returned, a second retransmission packet is transmitted from the transmission device 100. At this time, the selection control unit 241b selects the packet storage unit 244b, the retransmission packet 1 storage unit 245b, and the retransmission packet 2 storage unit 246b and instructs the combining unit 242b, and the error correction detection decoding processing unit 243b The first error detection correction process is performed by performing error correction detection decoding within a predetermined time on the result of combining the first retransmission packet and the second retransmission packet. The error correction detection decoding processing result is notified to the error detection determination unit 250, and when the error correction detection decoding is correctly completed, an acknowledgment ACK is received, and when the error correction detection decoding is not completed correctly, a negative response NAK is respectively received. It is returned to the transmitting device 100.

  When the first error detection correction process is not completed correctly, the second error detection correction process is performed as follows.

  The selection control unit 241b selects the packet storage unit 244b and the retransmission packet 2 storage unit 246b and instructs the combining unit 242b, and the error correction detection decoding processing unit 243b combines the initial transmission packet and the second retransmission packet. Error correction detection decoding is performed on the result. The result of the error correction detection decoding is notified to the error detection determination unit 250, and an acknowledgment ACK is transmitted to the transmission device only when the error correction detection decoding is correctly performed. If the error correction detection decoding is not completed correctly, the selection control unit 241b selects only the retransmission packet 2 storage unit 246b and instructs the combining unit 242b. The error correction detection decoding processing unit 243b Error correction detection decoding is performed on the second retransmission packet. The result of the error correction detection decoding process is notified to the error detection determination unit 250, and an acknowledgment ACK is transmitted to the transmission apparatus only when the error correction detection decoding is correctly performed. The above is the second error detection correction process.

  In the configuration shown in FIG. 11 above, the number of retransmission packets is set to “2”, but the present invention can be similarly applied to “3” or more.

  FIG. 12 shows a configuration of a demodulator according to the present invention. When an interference canceller is applied to an input signal, when signals of a plurality of users are transmitted on the same transmission path, signals from other users are removed. It is configured to improve the quality.

  The configuration shown in FIG. 12 shows an embodiment in which the demodulator 220 is configured with a four-stage interference canceller.

  The input signal IN passed from the receiving unit 210 is passed to the first stage interference canceller 222a, and at the same time passed to the second stage interference canceller via the delay unit 221a.

  The first-stage interference canceller 222a demodulates the input signal IN and outputs it as OUTa to the output selection unit 223. At the same time, the first stage interference canceller 222a receives the replica signal Sa that is a predicted value of each user's interference signal included in the input signal IN. Generated and delivered to the second-stage interference canceller 222b.

  Based on the replica signal Sa delivered from the first-stage interference canceller 222a, the second-stage interference canceller 222b removes the interference signal predicted by the other user from the input signal IN and outputs a signal with improved quality. The demodulated signal is output as OUTb to the output selection unit 223, and at the same time, the replica signal Sb with improved accuracy is delivered to the third-stage interference canceller 222c.

  The same applies to the third-stage interference canceller 222c. The result of demodulating the improved signal is output as OUTc to the output selection unit 223, and at the same time, the replica signal Sc with improved accuracy is output to the fourth-stage interference canceller 222d. Hand over to

  Similarly, the fourth stage interference canceller 222d, which is the final stage, outputs the result of demodulating the improved signal to the output selection unit 223 as OUTd.

  The output selection unit 223 selects the output signal from the number of stages specified by the stage number selection signal SL from the error detection determination unit 250, and passes it to the data selection unit 230 as the output signal OUT.

  Thus, when the received packet cannot be correctly detected and corrected, the error detection determination unit 250 selects a signal with improved quality from the output signals OUTa, OUTb, OUTc, and OUTd from the interference canceller. By passing it to the data selection unit 230, the accuracy of error detection and correction can be improved.

  In the embodiment shown in FIG. 12, the case of a four-stage configuration is described, but the number of stages is not limited to this, and an arbitrary number of stages is possible.

  FIG. 13 shows the configuration (1) of the interference canceller according to the present invention, and shows the configuration of the interference canceller 222a located in the first stage among the interference cancellers shown in FIG.

  The input signal IN delivered from the receiving unit 210 includes a demodulating unit Xa (1) that demodulates a signal assigned to the own device, and demodulating units Xa (2) to Xa that demodulate signals assigned to other users. passed to (k). Here, “i” in the notation Xa (i) is the identification number of the user who uses the same transmission path. Here, for convenience, “1” is assigned to the own device, and “2” to “k” are assigned to other users. It is assumed that it is assigned to.

  The signals demodulated by the demodulation units Xa (1) to (k) are sent to the provisional determination units Ya (1) to Ya (k) and replica generation units Za (1) to Za (k) provided for each user. Via these, replica signals Sa (1) to Sa (k) serving as reception prediction values for each user are generated and delivered to the interference canceller 222b at the next stage. Here, the output signal OUTa of the demodulator Xa (1) corresponding to its own device is delivered to the output selector 223.

  FIG. 14 shows the configuration of the second-stage interference canceller 222b as a representative example of the second-stage and subsequent interference cancellers in the configuration (2) of the interference canceller according to the present invention.

  The replica signals Sa (1) to Sa (k) for each user delivered from the first-stage interference canceller 222a are input to the signal selection unit R and are signals Rb obtained by synthesizing replica signals of other users other than the user. (1) to Rb (k) are passed to the interference cancellers Wb (1) to (k) provided for each user. For example, Rb (1) is a signal obtained by synthesizing Sa (2) to Sa (k), and Rb (2) is a signal obtained by synthesizing Sa (1) and Sa (3) to Sa (k).

The interference cancellers Wb (1) to Wb (k) subtract Rb (1) to Rb (k) from the input signal IN containing the interference signal of the other user passed from the delay unit 221a, respectively. Thus, the predicted value of the interference signal of the other user is removed to obtain a signal with improved quality. This signal is demodulated by the demodulating units Xb (1) to Xb (k), and then the tentative judging units Yb (1) to Yb (k) and the replica generating unit Zb, like the first stage interference canceller 222a. From (1) to Zb (k), replica signals Sb (1) to Sb (k), which are prediction values with higher accuracy of the interference signal, are generated and delivered to the interference canceller at the next stage. Since the demodulation unit Xb (1) corresponds to its own device, the output signal is delivered to the output selection unit 223 as the output signal OUTb of the interference canceller 222b.

  In this way, a signal with improved quality can be obtained by applying the interference canceller to the input signal IN.

  The interference canceller 222c and the interference canceller 222d operate similarly.

  In the embodiment shown in FIG. 12, the number of stages of the interference canceller is four, but is not limited to this, and the number of stages can be arbitrarily configured.

  In the embodiment shown in FIG. 12, the interference canceller replica is generated based on the output signal of the demodulator, but can also be realized using the output signal of the error detection corrector 240.

  The first error detection and correction process generates a replica signal using the outputs OUTa to OUTd of the demodulation unit, and the second error detection and correction process uses the output of the error detection and correction unit 240 to generate a replica signal. It can also be configured to generate.

  Examples of the above-described error detection and correction of the present invention include a method using an error correction code, a method in which a packet is turbo encoded and transmitted, and turbo decoding is repeated, and an interference canceller is used when demodulating a received packet. A method of removing an interference signal by passing multiple times and a method of performing error detection correction on the result of combining and combining the initial transmission packet and one or more retransmission packets held in the receiving device However, in addition to this, various embodiments are conceivable, such as when a packet is encoded with a convolutional code, and the present invention can be similarly applied.

  The embodiment of the present invention described above is as follows.

(Supplementary Note 1) In a retransmission control method when transmitting a packet from a transmission device to a reception device,
The transmitter encodes the packet and transmits it to the receiver;
The receiving device performs a first error detection correction process for the packet within a predetermined time, and when the error is resolved, returns an acknowledgment at a predetermined time point,
If the error is not resolved, a negative response is returned when a predetermined time elapses, and then the second error detection correction process is performed on the packet. When the error is resolved there, the second error detection correction process is terminated. Send back a positive response,
The transmission device transmits the next packet when the acknowledgment is received with respect to the transmitted packet, and transmits the retransmission packet generated based on the packet when the negative response is received.
If the acknowledgment is received between the time when the negative response is received and the time when the retransmission packet starts to be transmitted, the transmission of the retransmission packet is suppressed.
A retransmission control method characterized by the above.

(Supplementary note 2) In the retransmission control method described in supplementary note 1,
A retransmission control method characterized in that, when an error is resolved in the second error detection correction process, the second error detection correction process is terminated and the reception of the retransmission packet is waited.

(Supplementary Note 3) In the retransmission control method described in Supplementary Note 1 or Supplementary Note 2,
When the receiving device receives the retransmission packet, if the error of the previously received packet is resolved, an acknowledgment is returned.
A retransmission control method characterized by the above.

(Supplementary note 4) In the retransmission control method according to any one of supplementary notes 1 to 3,
A retransmission control method, wherein an acknowledgment is immediately returned when an error is eliminated by the first error detection correction process.

(Supplementary note 5) In the retransmission control method according to any one of supplementary notes 1 to 4,
The encoding uses a turbo code, and the first error detection correction process and the second error detection correction process perform error detection and correction by repeatedly performing turbo decoding.
A retransmission control method characterized by the above.

(Supplementary note 6) In the retransmission control method according to any one of supplementary notes 1 to 5,
The receiving apparatus holds the packet and the one or more retransmission packets;
The second error detection correction process performs error detection and correction by combining and combining the packet and one or more retransmission packets.
A retransmission control method characterized by the above.

(Supplementary note 7) In the retransmission control method according to supplementary note 6,
The first error detection correction process for the retransmission packet performs error detection and correction by combining and combining all of the packet and the one or more retransmission packets.
A retransmission control method characterized by the above.

(Supplementary note 8) In the retransmission control method according to any one of supplementary notes 1 to 7,
The receiver includes an interference canceller that removes interference of a received signal,
The first error detection correction process and the second error detection correction process perform error detection and correction by applying the interference canceller at least once to the received packet.
A retransmission control method characterized by the above.

(Supplementary note 9) In a transmission apparatus that transmits a packet by performing retransmission control to the reception apparatus,
Means for encoding the packet and transmitting it to the receiving device;
Means for receiving an acknowledgment and a negative response sent back from the receiving device after transmitting the packet to the receiving device;
Means for transmitting the next packet when the acknowledgment is received, and transmitting a retransmission packet generated based on the packet when the negative response is received;
If the acknowledgment is received between the time when the negative response is received and the time when the retransmission packet starts to be transmitted, the device includes means for suppressing transmission of the retransmission packet.
A transmission apparatus characterized by the above.

(Additional remark 10) In the receiving apparatus which carries out retransmission control and receives the encoded packet transmitted from the transmitting apparatus,
Means for performing a first error detection correction process on the packet within a predetermined time;
When the error is eliminated in the first error detection correction process, means for returning an affirmative response at a predetermined time point;
If the error is not resolved in the first error detection correction process, a means for performing a second error detection correction process for the packet by returning a negative response when a predetermined time has elapsed,
A receiving apparatus.

(Supplementary note 11) In the reception device according to supplementary note 10,
When an error is eliminated in the second error detection correction process, the second error detection correction process is terminated, and a means for returning an acknowledgment is provided.
A receiving apparatus.

(Supplementary Note 12) In the receiving device according to Supplementary Note 10 or Supplementary Note 11,
When an error is eliminated in the first error detection correction process, the device includes means for immediately returning an acknowledgment.
A receiving apparatus.

(Supplementary note 13) In the reception device according to any one of Supplementary note 10 to Supplementary note 12,
Means for receiving a turbo-encoded packet; and means for performing the first error detection correction process and the second error detection correction process by repeating turbo decoding.
A receiving apparatus.

(Supplementary Note 14) In the receiving device according to any one of Supplementary Notes 10 to 13,
Means for holding the packet and one or more of the retransmission packets;
Means for performing the second error detection correction process on the retransmission packet by combining and combining the packet and the one or more retransmission packets;
A receiving apparatus.

(Supplementary Note 15) In the receiving device according to any one of Supplementary Notes 10 to 14,
Means for performing the first error detection correction processing on the retransmission packet by combining and combining all of the packet and the one or more retransmission packets;
A receiving apparatus.

(Supplementary Note 16) In the receiving device according to any one of Supplementary Notes 10 to 15,
An interference canceller that removes interference of the received signal;
Means for performing the first error detection correction process and the second error detection correction process by applying the interference canceller at least once to a packet transmitted from the transmission device;
A receiving apparatus.

Operation sequence of retransmission control according to the present invention (1) Operation sequence of retransmission control according to the present invention (2) Operation sequence of retransmission control according to the present invention (3) Operation sequence of retransmission control according to the present invention (4) Operation flow chart of retransmission control of the present invention (1) Operation flow chart of retransmission control of the present invention (2) Operation flow chart of retransmission control according to the present invention (3) Configuration of transmitting apparatus according to the present invention Configuration of receiving apparatus according to the present invention Configuration of error detection and correction unit according to the present invention (1) Configuration of error detection and correction unit according to the present invention (2) Configuration of demodulation unit according to the present invention Configuration of interference canceller according to the present invention (1) Configuration of interference canceller according to the present invention (2) Flowchart of Retransmission Control by Conventional H-ARQ Scheme Flowchart of Retransmission Control by Conventional ARQ Method Retransmission control method using Type III H-ARQ scheme of the prior art Retransmission control method using Type II H-ARQ scheme of the prior art Retransmission control method using Type I H-ARQ scheme of the prior art Operation Sequence of Retransmission Control by Conventional SR Method Operation sequence of retransmission control by conventional GBN method Operation sequence of retransmission control by SAW method of the prior art

Explanation of symbols

100 Transmitter
101 packet generator
102 Memory unit
103 Retransmission packet generator
104 Data selection part
105 Error detection and correction section
106 Modulator
107 Transmitter
108 Receiver
109 Demodulator
110 Response signal analyzer
200 Receiver
210 Receiver
220 Demodulator
230 Data selector
240,240a, 240b Error detection and correction unit
250 Error detection judgment section
260 Response signal generator
270 Modulator
280 Transmitter
241a Turbo decoder
241b Selection control unit
242b Composite unit
243b Error correction detection decoding processor
244b Initial packet storage unit
245b Retransmission packet 1 storage unit
246b Retransmission packet 2 storage unit
220 Demodulator
221a, 221b, 221c Delay part
222a, 222b, 222c, 222d Interference canceller
223 Output selector
R signal selector
Rb (i) i = 1 to k
Sa (i), Sb (i) i = 1 to k replica signal
Wb (i) i = 1 to k Interference canceller
Xa (i), Xb (i) i = 1 to k demodulator
Ya (i), Yb (i) i = 1 to k
Za (i), Zb (i) i = 1 to k replica generator

Claims (5)

In a receiving apparatus that receives and controls retransmission of an encoded packet transmitted from a transmitting apparatus,
Means for performing a first error detection correction process on the packet;
Means for performing second error detection correction processing for performing error detection correction on the packet in a manner different from the first error detection correction processing ;
When an error is eliminated within a predetermined time in the first error detection correction process for the received packet, an acknowledgment requesting the next packet is made without executing the second error detection correction process. Means to return,
If the error is not resolved within a predetermined time in the first error detection correction process for the received packet, a negative response requesting a retransmission packet is returned, and the packet after the first error detection correction process is returned. Means for executing said second error detection and correction process, and when an error is eliminated by said second error detection and correction process, means for returning an acknowledgment requesting the next packet. A receiving device. The receiving device according to claim 1,
Means for stopping the second error detection correction process and executing the first error detection correction process for the retransmission packet when the retransmission packet is received during the execution of the second error detection correction process; A receiving apparatus comprising: The receiving apparatus according to claim 1 or 2,
If the error is resolved in the first or second error detection correction process, the acknowledgment is immediately returned , and if the error is not resolved even if the second error detection correction process is performed, a retransmission packet is sent. Means for continuing the second error detection correction process until the retransmission packet is received without returning a negative response to be requested ;
A receiving apparatus comprising: The receiving apparatus according to claim 1 or 2,
A receiving apparatus comprising: means for returning the acknowledgment upon receipt of the retransmission packet when an error is eliminated in the second error detection correction process. In the retransmission control method when transmitting a packet from a transmission device to a reception device,
The transmitting device encodes the packet and transmits the encoded packet to the receiving device;
The receiving apparatus performs the first error detection correction process on the packet, if the error is resolved within a predetermined time, the next packet to the packet after the error detection and correction processing of the first Send back the requested acknowledgment,
When the first error detection correction process is performed on the packet and an error is not resolved within a predetermined time, a negative response requesting a retransmission packet is returned and the packet after the first error detection correction process is sent If a second error detection correction process for performing error detection correction by a method different from the first error detection correction process is performed, and the error is eliminated by the second error detection correction process, Send back an acknowledgment requesting the packet,
A retransmission control method characterized by the above.

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