JP2008022516A - Communication method, transmitter, and receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve communication speed of a communication system by incorporating Outer-ARQ function. <P>SOLUTION: The communication method transmits packets from a transmitter 110 to a receiver 120. The packet that is transmitted has such information as indicates no discrimination information and no division information executed. When a re-transmission request is received about the specified packet that has been transmitted from the receiver 120, re-transmission of the specified packet or re-transmission of a plurality of sub division packets, provided by dividing the specified packet, is executed. The plurality of subdivision packets have the information for assembling the specified packet, meaning the discrimination information about the specified packet and the information indicating that division have been executed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a communication method, a transmitting apparatus, and a receiving apparatus having an automatic repeat control (ARQ) function, and data smaller than that at the time of initial transmission when retransmitting a packet that has not been correctly received. The present invention relates to a communication method, a transmission device, and a reception device that transmit the packet in size.

  3G LTE (Long Term Evolution), which is being standardized in the 3rd generation mobile communication system standardization project (3GPP: 3rd Generation Partnership Project), is a mobile communication system capable of 100 Mbps data transmission in the downlink. .

  In 3G LTE, it is agreed to perform ARQ in two layers. One is a hybrid ARQ (HARQ: Hybrid ARQ) performed in a Media Access Control (MAC) layer, and the other is an Outer-ARQ performed in a higher RLC (Radio Link Control) layer.

  In the following description, a data unit input to the RLC layer is referred to as RLC SDU (Service Data Unit), a data unit handled in Outer-ARQ is referred to as RLC PDU (Protocol Data Unit), and a data unit handled in HARQ is referred to as MAC PDU. .

  HARQ is a technique for improving retransmission efficiency by combining an error correction code and ARQ. The transmitting device transmits the MAC PDU with the correction code added thereto to the receiving device. When the received MAC PDU is normal or when the error can be corrected, the receiving device transmits ACK (Acknowledge) to the transmitting device. Conversely, if the received MAC PDU is abnormal and the error cannot be corrected, retransmission is requested by transmitting a NACK (Negative Ack Knowledge). When receiving the NACK, the transmitting apparatus transmits the corresponding MAC PDU again.

  Outer-ARQ relieves RLC PDUs contained in missing MAC PDUs when missing MAC PDUs occur due to HARQ retransmissions not succeeding within a certain number of times or within a certain time. Means. The transmitter assigns a series of numbers to the RLC PDU, and the receiver uses this number to report the PDU arrival status to the transmitter. Based on this report, the transmitting apparatus transmits an unarrived RLC PDU again. In the 3G system, the report of the arrival status of the PDU is a part of a function called a status report.

  Here, in the conventional 3G, the size of the RLC PDU handled by the RLC layer is semi-fixed and cannot be changed during communication. On the other hand, in 3G LTE, it has been agreed that the size of the RLC PDU can be flexibly changed according to the channel state at the time of transmission. In Outer-ARQ, with this resizing function, the RLC layer re-divides the RLC PDU into smaller RLC PDUs when the RLC PDU is retransmitted if the channel state has deteriorated from the initial transmission. This makes it possible to retransmit the RLC PDU under conditions where the transmission state is more severe.

  FIG. 11 is a diagram illustrating an example of a conventional PDU format and PDU re-segmentation method for realizing Outer-ARQ. As shown in FIG. 11, a MAC SDU (corresponding to the RLC SDU described above, hereinafter referred to as “SDU”) 1110 is composed of SDU1, SDU2, and SDU3.

  A MAC-I PDU (corresponding to the RLC PDU described above) formed by dividing the SDU 1110, hereinafter referred to as “PDU” 1120 includes a TSN (Transmission Sequence Number) 1121, an S (SubFraming Indicator) 1122, and It consists of LEX (Length extension Indicator) 1123 and SDU Seg1124. The TSN 1121 is a series of numbers added to the PDU 1120 unit.

  S1122 is information indicating Yes / No whether or not the PDU 1120 has been subdivided. The LEX 1123 is information indicating by Yes / No whether or not a plurality of SDU 1110 fragments are combined in the PDU 1120. SDU Seg1124 is a fragment of SDU1110. When a plurality of SDU 1110 fragments are combined in the PDU 1120 (LEX: Yes), a LI (Length Indicator) 1125 indicating the boundary position of each SDU 1110 fragment is added.

  A MAC-I SubPDU (hereinafter referred to as “SubPDU”) 1130 formed by re-dividing the PDU 1120 is configured by adding a SubPDU info 1131 to the configuration of the PDU 1120. The SubPDU info 1131 is information indicating which SubPDU 1130 is the SubPDU 1130 among the plurality of SubPDUs 1130 formed by re-dividing the PDU 1120. Thus, in this example, the PDU 1120 and the SubPDU 1130 have a format that basically follows the same rule (for example, see Non-Patent Document 1 below).

  FIG. 12 is a diagram illustrating another example of a conventional PDU format and PUD subdivision method for realizing Outer-ARQ. The RLC PDU 1210 (hereinafter referred to as “PDU”) shown in FIG. 12 is formed by dividing a block (not shown) (corresponding to the RLC SDU described above). The PDU 1210 includes a TSN 1211, an R 1212, an SI 1213, an LI 1214, and a Block 11215.

  The TSN 1211 is a series of numbers added to the PDU 1210 unit. R1212 is information indicating by 1/0 whether or not the PDU 1210 has been subdivided (corresponding to S1122 in FIG. 11). SI1213 is information indicating Yes / No whether or not a plurality of Block fragments are combined in the PDU 1210 (corresponding to LEX1123 in FIG. 11). The LI 1214 is information indicating the length of a block or a fragment of the block (corresponding to the LI 1125 in FIG. 11). Block 11215 is a fragment of Block.

  In addition, an RLC SubPDU (corresponding to the MAC-I SubPDU in FIG. 11; hereinafter referred to as “SubPDU”) formed by re-dividing the PDU 1210 is configured by adding a TSN 1221 and an R1222 to the configuration of the PDU 1210. The TSN 1221 is a series of numbers added to the SubPDU 1220 unit. R1222 is information indicating by 1/0 whether or not the SubPDU 1220 has been subdivided.

Thus, in this example, the PDU 1210 and the SubPDU 1220 have a format that basically follows the same rule. In this format, the SubPDU 1220 can be further divided any number of times. In this case, a new TSN each time it is subdivided
And R are added to the subdivided SubPDU (for example, refer to Non-Patent Document 2 below).

“Framing in the MAC entity”, [online], 3GPP, [May 15, 2006 search], Internet <URL: http: // www. 3 gpp. org / ftp / tsg_ran / WG2_RL2 / TSGR2_52 / Documents / R2-061012. zip> "LTE-Data framing", [online], 3GPP, [May 15, 2006 search], Internet <URL: http: // www. 3 gpp. org / ftp / tsg_ran / WG2_RL2 / TSGR2_52 / Documents / R2-060893. zip>

  However, in the above-described conventional technology, the PDU before subdivision and the SubPDU after subdivision are basically in the format according to the same rule. For this reason, each time a sub-segmentation is performed on a PDU in which a plurality of SDU fragments are combined, the transmitting apparatus determines in which sub-PDU the sub-segmentation is included in the sub-segment of the SDU, and further, There is a problem that it is necessary to recalculate the value and add it to the SubPDU including this boundary portion, and the processing of the transmitting apparatus at the time of retransmission becomes complicated.

  Further, in the above-described prior art, the receiving apparatus determines whether or not the PDU is subdivided for each received PDU, and if it is subdivided, all the SubPDUs necessary for assembling the PDU are all included. It is necessary to determine whether or not they are aligned, and the process of determining whether or not each PDU is aligned becomes complicated. For this reason, there is a problem that the process of determining whether all necessary PDUs have been prepared is complicated when assembling an SDU or requesting retransmission.

  Further, in the related art according to Non-Patent Document 2 described above, if the receiving apparatus cannot correctly receive the SubPDU, it makes a retransmission request by directly specifying the SubPDU that has not been correctly received. In other words, when a retransmission request is made by directly specifying a SubPDU, it is necessary to notify the transmitting device of the unique sequence number of the SubPDU in addition to the sequence number of the source PDU. The amount of information increases. For this reason, there is a problem that the band that can be used for data transmission is compressed by the control information necessary for the retransmission request.

  The present invention solves the above-described problems, and has a subdivision function without complicating Outer-ARQ processing and without compressing a data transmission band due to an increase in control information. It is an object to provide a communication method, a transmission device, and a reception device.

  A communication method according to the present invention is a communication method for transmitting a packet from a transmission device to a reception device, and a packet to be transmitted has identification information and information indicating that no division is performed and is transmitted. When a retransmission request is received for a specific packet from the receiving device, the specific packet is retransmitted or a plurality of divided packets obtained by dividing the specific packet are retransmitted. And the information for assembling the specific packet.

In addition, the transmission apparatus according to the present invention forms a first packet by dividing or combining information output from an upper layer in a transmission apparatus that retransmits a packet based on a retransmission request transmitted by the reception apparatus. A first layer to be transmitted and retransmitted and the first layer are provided independently, and a second layer for re-dividing the first packet by a predetermined number of divisions to form a plurality of second packets A layer, first control means for controlling retransmission of the first packet, second control means for controlling division of the first packet into the second packet, and the first packet or Transmitting means for transmitting the second packet to the receiving device.

  Further, the second packet formed by the transmitting apparatus according to the present invention restores this information from the first packet in the information output from the higher layer among the information included in the first packet. Information that is necessary to identify the first packet in the receiver, and that the first packet is a divided second packet. Information and information necessary for restoring the first packet from the second packet as a header.

  According to the above configuration, the second layer forming the second packet is provided independently of the first layer forming the first packet, and among the information included in the first packet, Since the information necessary to restore this information from the first packet at the receiving device is irrelevant to the process of forming the second packet, the first packet is retransmitted and the PDU first packet is subdivided. Each of the PDU formation processes when not performing the process is simplified. Specifically, in particular, the first packet retransmission process can be made substantially equivalent to the process performed in the current 3G system, and the amount of control information necessary for the PDU retransmission is also increased. It can be equivalent to the current 3G system.

  In addition, the receiving apparatus according to the present invention re-divides the first packet formed by dividing or combining predetermined information by the transmitting apparatus, or the first packet by the transmitting apparatus by a predetermined number of divisions. Receiving means for receiving the formed second packet; requesting means for sending a retransmission request to the transmitting device based on a receiving state of the first packet received by the receiving means; and receiving by the receiving means A first layer that assembles the second packets to be formed to form the first packet, and the first layer provided independently of the first layer and received by the receiving means or the first packet A second layer that assembles the first packet formed by one layer, restores the predetermined information, and outputs the predetermined information to an upper layer. And wherein the Rukoto.

  According to the above configuration, the second layer that restores the predetermined information is provided independently of the first layer that forms the first packet, and among the information included in the second packet, Since the information necessary to form one packet is removed at the second layer and is irrelevant to the process of restoring the predetermined information, the process of forming the first packet at the receiving device, and The process of restoring predetermined information is simplified. Specifically, in particular, the process of restoring the predetermined information can be made substantially equivalent to the process performed in the current 3G system.

  As described above, according to the present invention, it is possible to restore predetermined information without complicating PDU retransmission processing, without increasing the amount of control information necessary for PDU retransmission, and The packet re-segmentation function can be provided without complicating the process, and the packet re-segmentation process and the restoration process of the re-divided packet can be simplified.

  Exemplary embodiments of a communication method, a transmission device, and a reception device according to the present invention will be described below in detail with reference to the accompanying drawings.

(Embodiment)
(Basic configuration of communication system)
First, a basic configuration of a communication system according to an embodiment of the present invention will be described. FIG. 1 is a block diagram illustrating a basic configuration of a communication system according to an embodiment. As illustrated in FIG. 1, the communication system 100 according to the embodiment includes a transmission device 110 and a reception device 120. The transmission device 110 includes an upper layer 111, an RLC layer 112, a MAC layer 114, and a PHY layer 115.

  The RLC layer 112 includes an Outer-ARQ processing unit 113. Specifically, the RLC layer 112 includes an SDU division unit 113a (first layer) and a PDU division unit 113b (second layer) as sublayers. The SDU division unit 113a divides or combines RLC SDUs (hereinafter referred to as “SDUs”) output from the upper layer 111, and RLC PDUs (hereinafter referred to as “PDUs”) that are first packets (specific packets). Is output to the PDU divider 113b.

  The PDU divider 113b is provided independently below the SDU divider 113a. The PDU dividing unit 113b is a plurality of second packets (divided packets) by re-dividing the PDU output from the SDU dividing unit 113a by a predetermined number of divisions based on the retransmission request transmitted from the receiving device 120. An RLC SubPDU (hereinafter referred to as “SubPDU”) is formed and output to the MAC layer 114.

  However, PDU re-division is performed according to the transmission status (channel state), and is not always performed. When the PDU is not re-divided, such as at the first transmission time or when the communication state (transmission state) is not deteriorated, the PDU dividing unit 113b directly sends the PDU output from the SDU dividing unit 113a to the MAC layer 114. Output. Therefore, when the PDU is not re-divided, the processing in the PDU dividing unit 113b is hardly performed.

  Also, the PDU division unit 113b can change the number of divisions according to the transmission status and retransmit. For example, even though the transmission device 110 transmits a PDU by dividing it into sub-sized PDUs, the reception device 120 cannot correctly receive one or more of the sub PDUs, and has received a retransmission request regarding the PDU from the reception device 120. In this case, the number of divisions from the PDU to the SubPDU is changed, a SubPDU having a different size is re-formed, and the re-formed Sub PDU is output to the MAC layer 114. In this case, the division number may not be changed when the communication state is not deteriorated.

  Here, the RLC layer 112 includes a plurality of Outer-ARQ processing units 113. Thereby, the RLC layer 112 divides or subdivides a plurality of SDUs output from the upper layer 111 in parallel, and outputs the PDU or SubPDU formed by the division or subdivision to the MAC layer 114.

  The MAC layer 114 includes a multiplexing unit 114a and a HARQ processing unit 114b. The multiplexing unit 114a multiplexes PDUs or SubPDUs that are output in parallel in the RLC layer 112 to form a MAC PDU, and sequentially outputs the MAC PDU to the HARQ processing unit 114b. The HARQ processing unit 114b adds a correction code to the MAC PDU output from the multiplexing unit 114a, and transmits the MAC PDU to which the correction code is added to the reception device 120 via the PHY layer 115.

The HARQ processing unit 114b performs retransmission control based on the retransmission request transmitted from the receiving device 120. Specifically, when a retransmission request is transmitted from the receiving apparatus 120, the HARQ processing unit 114b transmits a MAC PDU corresponding to the transmission request to the receiving apparatus 120.

  The PHY layer 115 includes an encoding unit 115a, a modulation unit 115b, and a radio unit 115c. The encoding unit 115a encodes the MAC PDU output from the MAC layer 114, and outputs the encoded MAC PDU to the modulation unit 115b as a digital signal. Modulation section 115b converts the digital signal output from encoding section 115a into an analog signal, and outputs the analog signal to radio section 115c. The radio unit 115c transmits the analog signal output from the modulation unit 115b to the receiving device 120 by radio communication.

  The receiving apparatus 120 includes a PHY layer 121, a MAC layer 122, an RLC layer 123, and an upper layer 125. The PHY layer 123 includes a radio unit 121a, a demodulation unit 121b, and a decoding unit 121c. The radio unit 121a receives the analog signal transmitted from the transmission device 110 and outputs the analog signal to the demodulation unit 121b. The demodulator 121b converts the analog signal output from the radio unit 121a to a digital signal and outputs the digital signal to the composite unit 121c. The combination unit 121c decodes the digital signal output from the demodulation unit 121b and outputs the decoded digital signal to the MAC layer 122 as a MAC PDU.

  The MAC layer 122 includes a HARQ processing unit 122a and a separation unit 122b. The HARQ processing unit 122a combines and rearranges the MAC PDUs received from the transmission apparatus 110 via the PHY layer 121, and outputs them to the separation unit 122b. The demultiplexing unit 122b demultiplexes a plurality of PDUs or SubPDUs multiplexed in the MAC PDU output from the HARQ processing unit 122a, and outputs the demultiplexed data to the RLC layer 123. Also, the HARQ processing unit 122a notifies the reception status of the MAC PDU as an ACK / NACK signal to the HARQ processing unit 114b of the transmission apparatus 110, and the MAC PDU notified that the HARQ processing unit 114b has not been correctly received (NACK). Will be resent.

  The RLC layer 123 includes an Outer-ARQ processing unit 124. Specifically, the RLC layer 123 includes a PDU assembly unit 124a (first layer) and an SDU assembly unit 124b (second layer) as sublayers. When a SubPDU is output from the MAC layer 114, the PDU assembly unit 124a assembles a predetermined SubPDU and then outputs it as a PDU to the SDU assembly unit 124b.

  Further, when a PDU is output from the MAC layer 122, the PDU assembly unit 124a outputs this PDU as it is to the SDU assembly unit 124b. That is, when a SubPDU is received or not received, only the PDU is output to the SDU assembling unit 124b, and the SubPDU is not output. For this reason, the SDU assembly unit 124b does not need to determine whether or not the PDU has been subdivided and whether or not all of the SubPDUs have been subdivided. Even if it is transmitted, it can be operated without having to change the configuration of the SDU assembly unit.

  The receiving apparatus 120 includes a buffer (not shown), and the PDU or SubPDU received via the PHY layer 121 is held in the temporary buffer until it is assembled by the RLC layer.

  As described above, the SubPDU received by the receiving apparatus may include subPDUs that are retransmitted after changing the number of divisions according to the transmission status. For example, when the PDU assembling unit 124a receives a SubPDU that has been divided from the same PDU and whose number of divisions has been changed from the PDU division unit 113b of the transmission apparatus 110, the SubPDU before the change of the number of divisions held in the buffer is changed. By discarding, it is possible to prevent sub-PDUs having different numbers of divisions from being assembled.

  The SDU assembly unit 124b is provided above the PDU assembly unit 124a. The SDU assembling unit 124 b waits for predetermined PDUs output from the MAC layer 122 or the PDU assembling unit 124 a to be assembled, assembles the aligned PDUs, restores the SDU, and outputs the SDU to the upper layer 125. In addition, the SDU assembling unit 124b notifies the SDU dividing unit 113a of the transmitting apparatus 110 of the reception status of the PDU as a Status report, and retransmits the PDU that is notified that the SDU dividing unit 113a is not correctly received. Here, the RLC layer 112 includes a plurality of Outer-ARQ processing units 124, assembles a plurality of PDUs or SubPDUs output from the MAC layer 114 in parallel, and outputs an SDU to the upper layer 111.

  Here, the RLC layer 112 and the RLC layer 123 include a plurality of processing units 113 and an Outer-ARQ processing unit 124, respectively, and are configured to assemble a plurality of PDUs or SubPDUs in parallel. The number of units 113 or the Outer-ARQ processing unit 124 may be one. In this case, the combining unit 114a of the MAC layer 114 or the branching unit 122b of the MAC layer 122 can be omitted.

  In addition, although the SDU division unit 113a and the PDU division unit 113b, and the PDU assembly unit 124a and the SDU assembly unit 124b are configured as independent layers, they are independent in a logical relationship. This is not the case in the physical relationship when realized. Further, here, for convenience, the ACK / NACK signal and the Status report are represented as information that is directly notified between the corresponding layers of the reception device 120 and the transmission device 110. However, in an actual communication system, each information Is notified via a lower layer.

  In addition, here, it has been described that the MAC layer 114 transmits the PDU or SubPDU output from the RLC layer 113 as the MAC PDU to the receiving device 120 via the PHY layer 115. However, in the following description, the MAC PDU is irrelevant. Therefore, for convenience of explanation, it is assumed that the transmission device 110 transmits a PDU or SubPDU to the reception device 120. Similarly, the receiving apparatus 120 receives a PDU or a SubPDU.

(Outline of PDU and SubPDU format in communication system)
Next, an outline of the format of PDUs and SubPDUs in the communication system 100 according to the embodiment of the present invention will be described. FIG. 2 is a diagram for explaining an outline of the format of PDU and SubPDU in the communication system according to the embodiment. In FIG. 2, the SDU 210 is an SDU output from the upper layer 111. The PDU 220 is a PDU output by the SDU divider 113a. The SubPDU 230 is a SubPDU output by the PDU dividing unit 113b.

  Here, it is assumed that the SDU 210 includes SDU # 1 and SDU # 2. The SDU 210 includes an Hdr (Header) 211 and a Payload 212. Hdr211 is information relating to the SDU 210 itself, which is added to the head of the SDU 210. For example, the Hdr 211 is information relating to the destination of the SDU 210. Payload 212 is a data body to be originally transferred, excluding the Hdr 211 portion of the SDU 210.

  Here, it is assumed that the PDU 220 includes PDU # 1, PDU # 2, and PDU # 3. The PDU 220 includes an SN (Sequence Number) 221, an F (Re-segmentation Indicator Flag) 222, a Payload (PDU data) 223, and an LI (Length Indicator) 224. The SN 221 is a series of numbers in a finite range for identifying the PDUs 220. For example, the SN 221 values of PDU # 1, PDU # 2, and PDU # 3 are “1”, “2”, and “3”, respectively.

  F222 is information indicating whether or not the PDU 220 has been subdivided. Here, since PDU 220 is not subdivided, the values of F222 of PDU # 1, PDU # 2, and PDU # 3 are all “0”, for example. Conversely, the value of F222 in the SubPDU 230 in which the PDU 220 is subdivided is “1”, for example. Based on this information, the PDU assembly unit 124a of the receiving apparatus 120 can easily determine whether the output from the MAC layer 122 is a PDU or a SubPDU, and can perform processing according to the type.

  Payload (PDU data) 223 is obtained by dividing the SDU 210 into a predetermined number. Payload (PDU data) 223 may be a combination of two or more SDUs 210. Further, when the size of the SDU 210 is smaller than the size of the PDU 220, the entire SDU 210 may be included in one PDU 220 of the Payload (PDU data) 223. Further, when the size of the fragment of the SDU 210 is smaller than the size of the PDU 220, the remaining part of the PDU 220 may be filled with data having no meaning called padding.

  Here, Payload (PDU data) 223 of PDU # 1 is composed of the first half of the fragments divided into two parts of SDU # 1. Also, PDU # 2 Payload (PDU data) 223 includes the latter half of the two pieces of SDU # 1 and the first half of the pieces obtained by dividing SDU # 2 into two, Are combined. PDU # 3 is composed of the latter half of the two segments of SDU # 2.

  The LI 224 is information indicating the state of division and combination of the SDU 210. For example, the LI of PDU # 2 indicates the boundary portion between the latter half of the fragments divided into two of SDU # 1 and the first half of the fragments divided into two of SDU # 2. ing.

  Here, as the SubPDU 230, there are PDU # 2-1, PDU # 2-2, and PDU # 2-3, which are obtained by re-dividing PDU # 2 into three. The SubPDU 230 includes SN 221, F 222, Payload (SubPDU data) 231, and RI (Re-segmentation Information) 232. The SN 221 of the SubPDU 230 is a copy of the SN 221 of the source PDU 220. Here, since the SN value of PDU # 2 that is the division source is “2”, the SN values of PDU # 2-1, PDU # 2-2, and PDU # 2-3 are all “2”.

  F222 of SubPDU 230 is a copy of F222 of PDU 220. However, since the SubPDU 230 is obtained by re-dividing the PDU 220, the values of F222 of PDU # 2-1, PDU # 2-2, and PDU # 2-3 are all rewritten to “1”, for example.

  The Payload (SubPDU data) 231 of the PDU 230 is obtained by dividing the LI 224 of the PDU 220 and the Payload (SubPDU data) 223 for each size according to the number of divisions. That is, the PDU division unit 113b divides the LI 224 of the PDU 220 and the payload (PDU data) 223 into a single piece without distinguishing them.

  In addition, since the PDU dividing unit 113b has a payload (PDU data) 223 of the PDU 220 in which a plurality of fragments of the SDU 210 are combined, similarly, when there are a plurality of LI 224, a plurality of LI 224 and a plurality of SDUs 210 Divide the pieces into one unit. Here, the fragments of PDU # 2-1, PDU # 2-2, and PDU # 2-3 are assigned by dividing the LI224 of PDU # 2 and the payload (PDU data) 223 into three parts. Is.

  Thus, by treating the LI 224 and the payload (PDU data) 223 as one unit without distinguishing them, no matter how many PDUs 220 are formed from SDU 210 or SDU 210 fragments, a single SDU 210 is used. This group can be divided in exactly the same way as if it were formed from all or a piece of.

  The RI 232 of the SubPDU 230 is subdivision information related to Payload (SubPDU data) 231 and includes RI_L, RI_N, and RI_F (not shown). RI_L is information indicating the size of Payload (PDU data) 231. RI_N is information indicating the number of fragments among the fragments obtained by dividing the Payload (SubPDU data) 231 from the source PDU 220. Here, the RI_N values of PDU # 2-1, PDU # 2-2, and PDU # 2-3 are “1”, “2”, and “3”, respectively.

  RI_F is information indicating whether or not the Payload (SubPDU data) 231 is the last fragment among the fragments divided from the PDU 220 that is the division source. Here, among PDU # 2-1, PDU # 2-2, and PDU # 2-3 divided from PDU # 2, the last SubPDU 230 is PDU # 2-3. Therefore, for example, the value of RI_F in PDU # 2-3 is “1”, and the value of RI_F in PDU # 2-1 and PDU # 2-2 is “0”. Note that the expression method and arrangement of each component of the format described above are not limited to those described, and any expression method and arrangement may be used.

(Retransmission processing of communication system)
Next, retransmission processing of the communication system 100 according to the embodiment of the present invention will be described. FIG. 3 is a sequence diagram illustrating retransmission processing of the communication system according to the embodiment. In FIG. 3, the horizontal axis indicates time t. As shown in FIG. 3, first, the transmission apparatus 110 transmits PDU # 1 (only the numbers are shown; the same applies hereinafter) output from the SDU division unit 113a to the reception apparatus 120 (step S301). At this time, the PDU division unit 113b does not re-divide the PDU 220 output from the SDU division unit 113a.

  Next, the transmission apparatus 110 transmits PDU # 2 output from the SDU division unit 113a to the reception apparatus 120 (step S302). Here, it is assumed that the communication state between the transmission device 110 and the reception device 120 is deteriorated, and the reception device 120 cannot correctly receive this PDU # 2. In addition, the transmission apparatus 110 reduces the size of the PDU 220 to be transmitted later.

  Next, the transmitter 110 transmits, to the receiver 120, poll information for inquiring the reception status on the receiver 120 side, together with PDU # 3 output from the SDU divider 113a (step S303). When receiving the poll transmitted from the transmission device 110 in step S303, the reception device 120 transmits status information indicating that the PDU # 1 has been correctly received to the transmission device 110 (step S304).

  Here, the receiving apparatus 120 is configured to transmit the status information in accordance with the poll information transmitted from the transmitting apparatus 110. However, the receiving apparatus 120 may autonomously transmit the status information. For example, in the current 3G system, it is possible to adopt a method of periodically transmitting or transmitting when it is detected that the SN of the received PDU is discontinuous.

  Next, the transmission apparatus 110 transmits PDU # 4 and PDU # 5 output from the SDU division unit 113a to the reception apparatus 120 (steps S305 and S306). Next, when the transmitting apparatus 110 receives the status information transmitted from the receiving apparatus 120 in S304, the transmitting apparatus 110 re-divides PDU # 2 by the PDU dividing unit 113b (step S307).

  Next, the transmission apparatus 110 transmits PDU # 2-1 and PDU # 2-2 as SubPDU230 to the reception apparatus 120 (steps S308 and S309). Here, it is assumed that the communication state between the transmission device 110 and the reception device 120 has deteriorated, and the reception device 120 has not been able to correctly receive this PDU # 2-2. Further, the transmission apparatus 110 further reduces the size of the PDU 220 to be transmitted later.

  Next, the transmission apparatus 110 transmits the Poll information to the reception apparatus 120 together with PDU # 6 output from the SDU division unit 113a (step S310). When receiving the poll information transmitted from the transmission apparatus 110 in step S310, the reception apparatus 120 transmits status information indicating that the PDU # 1 has been correctly received at this time to the transmission apparatus (step S311). Next, the transmission apparatus 110 transmits PDU # 7 and PDU # 8 output from the SDU division unit 113a to the reception apparatus 120 (steps S312 and S313).

  Next, when the transmission apparatus 110 receives the status information transmitted from the reception apparatus 120 in S10, the transmission apparatus 110 re-divides the PDU # 2 by the PDU division unit 113b (step S314), and the PDU # 2-1 ′ to ## as the SubPDU 230. 2-4 ′ is transmitted to the receiving apparatus 120 (steps S315 to S318). Next, the receiving apparatus 120 assembles PDU # 2 based on the received PDU # 2-1 'to PDU # 2-4' (step S319), and ends a series of processes.

  Here, when the receiving apparatus 120 cannot correctly receive the SubPDU 230, the transmitting apparatus 110 increases the number of divisions from two to four, and transmits the SubPDU 230 formed by re-division so that the communication state is increased. Even in the case of deterioration, SubPDU 230 transmission is possible under robust conditions. On the other hand, the transmission apparatus 110 may transmit the same SubPDU 230 again without changing the number of divisions based on the communication state or the like.

  In addition, here, when the receiving apparatus 120 cannot correctly receive a part of the SubPDU 230, the division source PDU 220 of the SubPDU 230 is changed and transmitted again. As a result, the status information transmitted by the receiving apparatus 120 is sufficient, for example, only the information that “up to PDU # 1 has been correctly received”, and the information amount of the status information can be reduced.

(Procedure for processing in which the PDU division unit of the transmission device re-divides the PDU)
Next, a procedure of processing in which the PDU division unit 113b of the transmission apparatus 110 according to the embodiment of the present invention redivides the PDU 220 will be described. FIG. 4 is a flowchart of a process procedure in which the PDU division unit of the transmission apparatus according to the embodiment re-divides the PDU 220. FIG. 5 is a diagram for explaining the creation and formation process of the SubPDU 230 in correspondence with the steps in FIG.

  Here, a case will be described in which the unit size of the LI 224 and the payload (PDU data) 223 of the PDU 220 output from the SDU divider 113 a is 200 octets, and the PDU divider 113 b divides the PDU 220 into two SubPDUs 230. That is, here, the PDU divider 113b subdivides the LI 224 and Payload (PDU data) 223 of the PDU 220 into two (100 octets each).

  The variable n is a variable that indicates the number of the SubPDU 230 out of the SubPDUs 230 that are formed by re-dividing the sub-PDU 230 that is being created and formed from the original PDU 220. In FIG. 2, the first SubPDU 230 is SubPDU # 1, but here, for convenience of explanation, the value of n of the first SubPDU 230 is described as “0” (the same applies to the following description). Here, since the PDU 220 is divided into two, when the value of n is 0 “1”, it indicates that the SubPDU 230 being created and formed is the SubPDU 230 at the head end. When n is 1, it indicates that the sub-PDU 230 being formed is the last sub-PDU 230.

  First, the PDU 220 output from the SDU division unit 113a is stored in a buffer (not shown) of the transmission device 110 (step S401, see FIG. 5). Next, “0” is substituted into the variable n (step S402). That is, the created SubPDU 230 is set as the first SubPDU 230.

  Next, “1” is read from the addresses “0” of the buffer. (Step S403, see FIG. 5). That is, the SN 221 and the F 222 of the division source PDU 220 are read. Next, the value of F222 is changed from “0” to “1” (step S404, see FIG. 5). In other words, information indicating that the SubPDU 230 being formed has been subdivided is added.

  Next, it is determined whether or not the value of the variable n is “1” (step S405). That is, it is determined whether the SubPDU 230 being formed is the last SubPDU 230. When the value of the variable n is “1” (step S405: Yes), RI_F (value: 1) and RI_N (value: n) are added to the subPDU 230 being formed (step S406, see FIG. 5). That is, information indicating that the sub PDU 230 being formed is the last sub PDU 230, and information indicating the sub PDU 230 of the sub PDU 230 (here, n = 1) are added.

  In step S405, when the value of the variable n is “0” (step S405: No, refer to FIG. 9), RI_F (value: 0) and RI_N (value: n) are added to the subPDU 230 being formed (step S407). (See FIG. 5). That is, information indicating that the sub-PDU 230 being formed is not the last sub-PDU 230, and information indicating the sub-PDU 230 of the sub-PDU 230 (here, n = 0) are added.

  Next, RI_L (value: 100) is added to the SubPDU 230 being formed (step S408, see FIG. 5). That is, information indicating that the size of the fragment of the source PDU 220 included in the subPDU 230 being formed is 100 octets is added. Next, “2 + 100 * (n + 1) −1” is read out from the buffer address “2 + 100 * n” (step S409, see FIG. 5). That is, 100 octets are read out as a payload (SubPDU data) 231 of the SubPDU 230 being formed from a set of the payload (PDU data) 223 and the LI 224 of the source PDU 220.

  Next, the SubPDU 230 composed of SN221, F222, RI_N, RI_F, RI_L and Payload (SubPDU data) 231 is output to the MAC layer 114 (step S410). Next, it is determined whether or not the value of the variable n is “1” (step S411). That is, it is determined whether or not the SubPDU 230 output in S411 is the last SubPDU 230. When the value of the variable n is “0” (step S411: No), “1” is added to the variable n (step S412), and the process returns to step S403 to continue the processing. If the value of the variable n is “1” (step S411: Yes), the series of processes is terminated.

  Thus, even when the PDU 220 to which a plurality of SDUs 210 or fragments of the SDUs 210 are combined is subdivided by collectively subdividing the LI 224 and the payload (PDU data) 223 of the PDU 220 without distinguishing them, the combination of the SDUs 210 is combined. Therefore, it is not necessary to determine which SubPDU 230 after the re-division includes the boundary portion of LI and recalculate the value of the LI 224.

(Management table provided in the PDU assembly unit of the receiving device)
Next, a management table provided in the PDU assembly unit 124a of the receiving device 120 according to the embodiment of the present invention will be described. FIG. 6 is a diagram illustrating an example of a management table provided in the PDU assembly unit of the receiving apparatus according to the embodiment. The PDU assembly unit 124a includes a management table a (610) and a management table b (620) shown in FIG. The management table 610 includes SN 611, C 612, Final 613, and Valid 614 for each of the plurality of PDUs 220.

  SN 611 is a copy of SN 221 of each PDU 220. C612 is information indicating whether or not the PDU 220 is subdivided. For example, the value of C612 is “1” when the PDU 220 is subdivided, and “0” when the PDU 220 is not subdivided.

  Final 613 is the RI_N value of the last sub PDU 230 among the plurality of sub PDUs 230 formed by dividing the PDU 220. That is, when the SubPDU 230 whose RI_F is 1 is received, the value of RI_N of the SubPDU 230 is written in the Final 613.

  A plurality of Valid 614 are provided. Here, the management table 610 includes eight Valids 614 of Valid (0) to (7). The Valid 614 corresponds to each SubPDU 230 after the PDU 220 is subdivided, and is information indicating whether or not the corresponding SubPDU 230 has been correctly received. The initial value of Valid 614 is, for example, “0”. For example, when the PDU assembly unit 124a receives the SubPDU 230 having RI_N “0”, the PDU assembly unit 124a writes “1” to the corresponding Valid (0).

  Here, since eight Valid 614s are provided, it is possible to cope with the assembly of the PDU 220 divided into a maximum of eight. In addition, when the SubPDU 230 is less than 8, for example, when the PDU 220 is divided into two, when the SubPDU 230 PDU # 2-2 with RI_N “1” is received, Valid (1) to (7) Write “1” to all of

  The management table 620 is composed of an address 621 and a length 622. In each row, an Address 621 indicating the head address on a buffer (not shown) provided in the receiving apparatus 120 in which a fragment of one SubPDU 230 is stored and a Length 622 indicating the length of this fragment are stored in association with each other. ing. Here, the Address 621 and the Length 622 of each SubPDU 230 of the PDU 220 whose SN 611 of the management table 610 is “0” are stored in the 0th to 7th rows of the management table 620, respectively.

  Each time the PDU assembly unit 124a of the receiving device 120 receives the SubPDU 230, it writes the payload (SubPDU data) 231 of the received SubPDU 230 into the buffer. The PDU assembly unit 124a updates the management table 610 and the management table 620 every time the payload (SubPDU data) 231 of the received SubPDU 230 is written to the buffer.

(Processing procedure in which the PDU assembly unit assembles the PDU)
Next, a process procedure for assembling the PDU 220 by the PDU assembly unit 124a of the receiving apparatus 120 according to the embodiment of the present invention will be described. FIG. 7 is a flowchart of a process procedure in which the PDU assembly unit of the receiving apparatus according to the embodiment assembles a PDU. FIG. 8 is a diagram for explaining the PDU assembling process corresponding to the steps of FIG. The variable n is a variable indicating the number of the SubPDU 230 among the SubPDUs 230 that are divided from the divisional source PDU 220.

  First, it waits for the SubPDU 230 to be input from the MAC layer 114 (step S701: No loop). When the SubPDU 230 is input (Step S701: Yes), the input SubPDU is stored in the buffer, and the management table 610 and the management table 620 are updated (Step S702).

  Next, the management table 610 is read (step S703). Next, it is determined whether or not all Valid 614 values in the management table 610 are all “1” (step S704). That is, it is determined whether all the SubPDUs 230 corresponding to the PDU 220 being assembled have been received. Next, “0” is substituted into the variable n (step S705). That is, the SubPDU 230 to be read is set as the first SubPDU 230.

  Next, the SN 611 is read from the management table 610 (step S706, see FIG. 8). Next, Address 621 and Length 622 corresponding to the SubPDU 230 being read are read from the management table 620 (step S707). Next, “Address + Length−1” is read from the address “Address” of the buffer (step S708, see FIG. 8). That is, Payload (PDU data) 231 of the SubPDU 230 is read from the buffer based on the Address 621 and the Length 622 read in Step S707.

  Next, it is determined whether or not the value of the variable n is equal to Final 613 (step S709). That is, it is determined whether or not the sub-PDU 230 being read is the last sub-PDU 230 among the sub-PDUs 230 divided from the original PDU 220. If the value of the variable n is not equal to the Final 613 (step S709: No), “1” is added to the variable n (step S710), and the process returns to step S707 to continue the processing. When the value of the variable n is equal to Final 613 (step S709: Yes), the assembled PDU 220 is output to the SDU assembly unit 124b (step S711), and a series of processes is terminated.

(Management table provided in the PDU assembly unit of the receiving device)
Next, a management table provided in the PDU assembly unit 124a of the receiving device 120 according to the embodiment of the present invention will be described. FIG. 9 is a diagram illustrating an example of a management table provided in the PDU assembly unit of the receiving apparatus according to the embodiment. The PDU assembly unit 124a includes a management table 900 shown in FIG. The management table 900 includes Valid 901, Address 902, and Length 903 for each of the plurality of PDUs 220.

  Valid 901 is information indicating whether or not the PDU 220 has been correctly received. The initial value of Valid 901 is “0”, for example. For example, when receiving the PDU 220, the SDU assembly unit 124 b writes “1” in the Valid 901 of the row number corresponding to the SN of the PDU 220.

  Address 902 is the top address on the buffer where Payload (PDU data) 223 of the PDU 220 is stored. Length 903 is information indicating the length of this (PDU data) 223.

  As described above, the management table 900 does not include information indicating the presence / absence of subdivision or information regarding the SubPDU when subdivision is performed. When receiving the status information in response to the poll information transmitted from the transmission device 110, the reception device 120 can obtain necessary information only by referring to only the valid 901 of the row number corresponding to the SN of the management table 900. it can.

(Example of PDU and SubPDU format)
Next, an example of the format of the PDU 220 and the SubPDU in the communication system 100 according to the embodiment of the present invention will be described. FIG. 10 is a diagram illustrating an example of a PDU format in the communication system according to the embodiment. In this embodiment, an AMD (Asynchronous Mode Data) PDU format, which is a PDU of a conventional 3G system, is applied to the format of the PDU 220 according to the embodiment of the present invention.

  The PDU 1020 is an embodiment of the PDU 220 shown in FIG. SubPDU 1030 is an embodiment of SubPDU 230 shown in FIG. As shown in FIG. 10, the PDU 1020 includes a D / C (Data / Control) 1021, an SN 1022, a P (Polling Bit) 1023, an HE (Header Extension Type) 1024, an LI 1025, an E1026, and a Payload (PDU). Data) 1027. Payload 1027 corresponds to Payload 223 in FIG.

  The D / C 1021 is information for identifying a data PDU and a control PDU, and the D / C 1021 in the PDU 1020 indicates that the PDU 1020 is a data PDU. SN 1022 is a series of numbers in a finite range for identifying PDUs 1020 as described with reference to FIG. P1023 is a bit used when inquiring the reception status on the receiving apparatus 120 side, and the Poll information described in FIG. 3 is transmitted using this bit.

  The HE 1024 is information including information indicating whether or not the LI 1025 is included in the PDU 1020 and information indicating whether or not the PDU 1020 is subdivided (corresponding to F222 in FIG. 2). In the AMD PDU format of the conventional 3G system, 2 bits are allocated to HE.

  The least significant bit (LSB Less Significant Bit) of the two bits of the HE is information indicating whether or not the LI is included in the AMD PDU. Further, the most significant bit (MSB: Most Significant Bit) of the HE is not used. Therefore, in the present invention, information indicating whether or not the PDU 1020 has been subdivided is assigned to the MSB of the HE 1024.

  For example, when the value of the HE 1024 is “00”, the HE 1024 indicates that the PDU 1020 is not subdivided and the PDU 1020 does not include the LI 1025. When the value of the HE 1024 is “01”, the HE 1024 indicates that the PDU 1020 is not subdivided, and the PDU 1020 includes the LI 1025. Since the PDU 1020 is not subdivided, the MSB value of the HE 1024 of the PDU 1020 is “0”.

  The LI 1025 is information indicating a boundary portion of the combination when the PDU 1020 includes a plurality of fragments of the SDU 210 combined. The LI 1025 does not exist when only one fragment of the SDU 210 is included in the PDU 1020 (when no boundary portion exists). E1026 added after the LI1025 is information indicating whether the LI1025 or the Payload (PDU data) 1027 follows.

  For example, when the value is “0”, E1026 indicates that LI1025 follows E1026. On the other hand, E1026 indicates that when the value is “1”, Payload (PDU data) 1027 follows E1026. Here, the case where LI 1025 follows E1026 is a case where there are two or more boundary portions for combining fragments because the PDU includes three or more SDU 210 fragments.

  Payload (PDU data) 1027 is a fragment of SDU 210 or divided SDU 210. Further, the Payload (PDU data) 1027 may be a combination of SDU 210 or SDU 210 fragments. If the total amount of fragments of the SDU 210 is smaller than the size of the PDU 1020, the remaining part of the PDU 1020 may be filled with data having no meaning called padding. The presence or absence of padding is displayed by adding an LI 1025 having a predefined value.

  The SubPDU 1030 includes a D / C 1021, an SN 1022, a P1023, an HE 1031, an RI_N 1032, an RI_F 1033, an RI_L 1034, and a Payload (SubPDU data) 1035. The SubPDU 1030 is formed by dividing the PDU 1020 into three parts. Note that, in the configuration of the SubPDU 1030, the same configuration as the configuration of the PDU 1020 is denoted by the same reference numeral, and the description thereof is omitted. However, Payload 1035 corresponds to Payload 231 in FIG. The HE 1033 is information including information indicating whether or not the SubPDU 1030 has been subdivided and information indicating whether or not the SubPDU has been transmitted by changing the number of divisions.

  The HE 1024 in the PDU 1020 includes information indicating whether or not the LI 1025 is included in the PDU 1030. However, the Sub PDU 1030 handles the LI 1025 of the PDU 1020 and the Payload (PDU data) 1027 without distinction, and also includes a Payload (Subload 1030 specific to the SubPDU 1030). (SubPDU data) 1035 does not include a boundary portion. Accordingly, the HE 1031 in the SubPDU 1030 does not need information indicating whether or not the LI is included.

  For this reason, in the present invention, information indicating whether or not the SubPDU 1030 is transmitted with the division number changed is assigned to the LSB of the HE 1031 of the SubPDU 1030. That is, for example, when a SubPDU 1030 formed by dividing the PDU 1020 into three is first transmitted, the MSB value of the HE 1031 of the SubPDU 1030 is “0”. Further, when a SubPDU 1030 obtained by dividing the same PDU 1030 into six is transmitted thereafter, the MSB value of the HE 1031 of the SubPDU 1030 is always “1”.

  By the way, the information indicating whether or not the SubPDU 1030 is transmitted after changing the number of divisions is the SubPDU 1030 after re-division or the SubPDU 1030 after re-division for the receiving device 120. It is necessary to notify you. For example, in the example shown in FIG. 3, PDU # 2-1 obtained by re-dividing PDU # 2 in step S307 and PDU # 2-1 obtained by re-dividing PDU # 2 in step S314 are different SubPDUs. Contain the same SN and RI_N and are indistinguishable.

  For this reason, information indicating whether or not the SubPDU 1030 is transmitted with the division number changed is required. For example, if the PDU assembly unit 124a receives a SubPDU 1030 that includes the same SN 1022 and has a different MSB value in the HE 1031, the PDU assembly unit 124a determines that the number of divisions has been changed, and before that, The SubPDU 1030 is discarded.

  For example, when the value of the HE 1031 is “10”, the HE 1031 indicates that the SubPDU 1030 has been subdivided, and that the SubPDU 1030 has not been transmitted with the division number changed. When the value of the HE 1031 is “11”, the HE 1031 indicates that the SubPDU 1030 has been subdivided, and that the SubPDU 1030 has been transmitted by changing the number of divisions. Note that since the SubPDU 1030 has been subdivided, the MSB value of the HE 1031 of the SubPDU 1030 is always “1”.

  As described with reference to FIG. 2, RI_N 1032 is information indicating the number of fragments among the fragments divided from the PDU 1020 that is the division source. RI_F 1033 is information indicating whether or not the fragment is the last fragment among the fragments divided from the PDU 1020 that is the division source. RI_L 1034 is information indicating the size of Payload (SubPDU data) 1035. Payload (SubPDU data) 1035 is a fragment obtained by dividing a group of LI 1025 of PDU 1020 and Payload (PDU data) 1027.

  In this way, by assigning information indicating whether or not the PDU has been subdivided to the MSB of the HE that was not used in the AMD PDU format of the 3G system, the size of the AMD PDU format of the 3G system is reduced. It is possible to realize the Outer-ARQ function without increasing it.

  As described above, according to the communication method, the transmission apparatus, and the reception apparatus according to the present invention, the SDU division unit and the PDU division unit of the transmission apparatus are provided as independent layers, thereby performing PDU re-division. When there is no PDU, the process of PDU formation is simplified.

  In addition, when the transmission device re-divides a PDU, the LI and Payload (PDU data) in the PDU are divided together without being distinguished, so that the boundary portion of the SDU combination is included in which sub-PDU after re-division And the process of recalculating the value of LI and adding it to the SubPDU including this boundary portion becomes unnecessary.

  In addition, by providing the SDU assembly unit and the PDU assembly unit of the receiving apparatus as independent layers, the SDU assembly process in the receiving apparatus is simplified when the transmitting apparatus does not re-divide the PDU. .

  In addition, when the receiving apparatus makes a retransmission request, it is only necessary to notify the transmitting apparatus of the PDU serial number, and there is no need to notify the SubPDU unique serial number. For this reason, the amount of control information necessary for the retransmission request is reduced.

  As described above, most transmission errors can be corrected by HARQ. Therefore, there is no need to configure the communication system so that all PDUs can be subdivided. For example, by setting an upper limit on the number of PDUs that can be subdivided at the same time, the configuration of the management table or the like may be minimized.

  The transmission method or the reception method described in this embodiment can be realized by executing a program prepared in advance on a computer such as a personal computer or a workstation. This program is recorded on a computer-readable recording medium such as a hard disk, a flexible disk, a CD-ROM, an MO, and a DVD, and is executed by being read from the recording medium by the computer. The program may be a transmission medium that can be distributed via a network such as the Internet.

(Supplementary note 1) A communication method for transmitting a packet from a transmitting device to a receiving device,
The packet to be sent has identification information and information indicating that no division is performed,
When a retransmission request is received from a receiving device for a specific packet sent out, the specific packet is retransmitted or a plurality of divided packets obtained by dividing the specific packet are retransmitted,
The communication method according to claim 1, wherein the plurality of divided packets include the identification information of the specific packet, information indicating that the division is performed, and information for assembling the specific packet.

(Supplementary note 2) The communication method according to supplementary note 1, wherein retransmission of the specific packet and selection of retransmission of a plurality of divided packets obtained by dividing the specific packet are performed based on a transmission state.

(Supplementary note 3) The communication method according to Supplementary note 1 or Supplementary note 2, wherein the number of divisions of the fragmented packet is performed based on a transmission state.

(Supplementary Note 4) A communication method for transmitting a packet from a transmitting device to a receiving device,
Transmission control by a first layer that divides or combines information output from higher layers to form a first packet;
Transmission control is performed by a second layer that is provided independently of the first layer and divides the first packet to form a plurality of second packets,
Retransmission of a packet from the transmitting device to the receiving device is performed by either the first packet or the second packet.

(Supplementary Note 5) The first and second packets have identification information and information indicating presence / absence of division in a common format, and information for assembling the specific packet. The communication method according to attachment 4.

(Supplementary note 6) The communication method according to supplementary note 5, wherein selection of retransmission by the first packet and retransmission by the second packet is performed based on a transmission state.

(Supplementary note 7) The communication method according to supplementary note 5 or 6, wherein the number of divisions of the second packet with respect to the first packet is changed based on a transmission state.

(Supplementary Note 8) A transmission device that transmits a packet to a reception device,
The packet to be sent has identification information and information indicating that no division is performed,
When a retransmission request is received from a receiving device for a specific packet sent out, the specific packet is retransmitted or a plurality of divided packets obtained by dividing the specific packet are retransmitted,
The transmission apparatus according to claim 1, wherein the plurality of divided packets include the identification information of the specific packet, information indicating that the division is performed, and information for assembling the specific packet.

(Supplementary note 9) The transmission apparatus according to supplementary note 8, wherein retransmission of the specific packet and selection of retransmission of a plurality of divided packets obtained by dividing the specific packet are performed based on a transmission state.

(Supplementary note 10) The transmission apparatus according to supplementary note 8 or supplementary note 9, wherein the number of divisions of the divided packet is performed based on a transmission state.

(Additional remark 11) It is a receiver which receives the packet transmitted from a transmitter, Comprising:
The received packet has identification information and information indicating that no division is performed,
A retransmission request for the received specific packet is made to the transmission apparatus, and the received retransmission packet is the specific packet having information indicating that the division is not performed, or the same identification information as the specific packet And determining whether the packet is a fragmented packet having information indicating that the fragmentation is being performed and information for assembling the packet,
When the received retransmission packet is the divided packet, the receiving apparatus assembles the specific packet based on information for assembling the packets of a plurality of the divided packets.

(Supplementary note 12) The reception according to Supplementary note 11, wherein the request for retransmission of the received specific packet and the request for retransmission of a plurality of divided packets obtained by dividing the specific packet are made based on a transmission state. apparatus.

(Supplementary note 13) The supplementary note 11 or the supplementary note 12, wherein the division packet having the number of divisions changed based on a transmission state and information on the change of the division number are received and the specific packet is assembled. Receiver.

(Supplementary note 14) The receiving apparatus according to any one of supplementary notes 11 to 13, wherein the specific packet having the same identification number of the specific packet is assembled.

(Additional remark 15) The said division | segmentation packet contains the information that the said division | segmentation number was changed, and when the said division | segmentation packet containing the information that the said division | segmentation number was changed is received, the identification same as the said division | segmentation packet 15. The receiving apparatus according to appendix 13 or 14, wherein the received divided packet having a number is discarded.

  As described above, the communication method, the transmission apparatus, and the reception apparatus according to the present invention are useful for a communication system having an ARQ function, and are particularly suitable for realizing Outer-ARQ in the system.

1 is a block diagram showing a basic configuration of a communication system according to an embodiment. It is a figure explaining the outline | summary of the format of PDU and SubPDU concerning embodiment. It is a sequence diagram which shows the resending process of the communication system concerning Embodiment. It is a flowchart which shows the procedure of the process which the PDU division part of the transmission device concerning an embodiment re-divides PDU. It is a figure explaining the formation process of SubPDU concerning an embodiment corresponding to the step of FIG. It is a figure which shows an example of the management table with which the PDU assembly part of the receiver concerning embodiment is provided. It is a flowchart which shows the procedure of the process which the PDU assembly part of the receiver concerning Embodiment assembles PDU. It is a figure explaining the assembly process of PDU concerning an embodiment corresponding to the step of FIG. It is a figure which shows an example of the management table with which the PDU assembly part of the receiver concerning embodiment is provided. It is a figure explaining the Example of the format of PDU concerning Embodiment. It is a figure which shows an example of the conventional PDU format and PUD subdivision method for implement | achieving Outer-ARQ. It is a figure which shows another example of the conventional PDU format and PUD subdivision method for implement | achieving Outer-ARQ.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Communication system 110 Transmission apparatus 112, 123 RLC layer 113, 124 Outer-ARQ process part 113a SDU division part 113b PDU division part 114, 122 MAC layer 114b, 122a HARQ process part 115, 121 PHY layer 120 Reception apparatus 124a PDU assembly part 124b SDU assembly part 210, 1020 SDU
220, 1030 PDU
230 SubPDU
610, 620, 900 management table

Claims (10)

A communication method for transmitting a packet from a transmitting device to a receiving device,
The packet to be sent has identification information and information indicating that no division is performed,
When a retransmission request is received from a receiving device for a specific packet sent out, the specific packet is retransmitted or a plurality of divided packets obtained by dividing the specific packet are retransmitted,
The communication method according to claim 1, wherein the plurality of divided packets include the identification information of the specific packet, information indicating that the division is performed, and information for assembling the specific packet.   2. The communication method according to claim 1, wherein retransmission of the specific packet and selection of retransmission of a plurality of divided packets obtained by dividing the specific packet are performed based on a transmission state. A communication method for transmitting a packet from a transmitting device to a receiving device,
Transmission control by a first layer that divides or combines information output from higher layers to form a first packet;
Transmission control is performed by a second layer that is provided independently of the first layer and divides the first packet to form a plurality of second packets,
Retransmission of a packet from the transmitting device to the receiving device is performed by either the first packet or the second packet.   The said 1st and said 2nd packet has the information which shows the identification information of the common format and the presence or absence of the division | segmentation, and the information for assembling the said specific packet, The said 3rd packet is characterized by the above-mentioned. The communication method described. A transmitting device that transmits a packet to a receiving device,
The packet to be sent has identification information and information indicating that no division is performed,
When a retransmission request is received from a receiving device for a specific packet sent out, the specific packet is retransmitted or a plurality of divided packets obtained by dividing the specific packet are retransmitted,
The transmission apparatus according to claim 1, wherein the plurality of divided packets include the identification information of the specific packet, information indicating that the division is performed, and information for assembling the specific packet.   The transmission apparatus according to claim 5, wherein retransmission of the specific packet and selection of retransmission of a plurality of divided packets obtained by dividing the specific packet are performed based on a transmission state. A receiving device that receives a packet transmitted from a transmitting device,
The received packet has identification information and information indicating that no division is performed,
A retransmission request for the received specific packet is made to the transmission apparatus, and the received retransmission packet is the specific packet having information indicating that the division is not performed, or the same identification information as the specific packet And determining whether the packet is a fragmented packet having information indicating that the fragmentation is being performed and information for assembling the packet,
When the received retransmission packet is the divided packet, the receiving apparatus assembles the specific packet based on information for assembling the packets of a plurality of the divided packets. 8. The receiving apparatus according to claim 7, wherein a request for retransmission of the received specific packet and a request for retransmission of a plurality of divided packets obtained by dividing the specific packet are made based on a transmission state.   9. The receiving apparatus according to claim 7, wherein the specific packet having the same identification number is assembled.   The divided packet includes information indicating that the number of divisions has been changed, and when receiving the divided packet including information indicating that the number of divisions has been changed, a reception having the same identification number as the divided packet is received. The receiving apparatus according to claim 9, wherein the received divided packet is discarded.

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