JP4820326B2 - Delivery confirmation information transmission method and reception side device - Google Patents

Description

  The present invention relates to a delivery confirmation information transmission method in which a reception side apparatus transmits delivery confirmation information for a packet from a transmission side apparatus, and a reception side apparatus.

  In 3GPP, which is an organization that standardizes third generation mobile communication systems, LTE (Long Term Evolution) is used to dramatically improve transmission speed and shorten transmission delay in a radio access network (RAN). ), And the standard specifications for the elemental technologies related to the study are being developed.

  As shown in FIG. 1, a radio access network (E-UTRAN: Evolved Universal Terrestrial RAN) in an LTE mobile communication system includes a mobile station UE (User Equipment), a radio base station eNB (E-UTRAN Node B), and The mobile station UE and the radio base station eNB are configured to perform communication via a radio link (RL: Radio Link).

  Further, each of the mobile station UE and the radio base station eNB is configured to terminate an RLC (Radio Link Control) sublayer, a MAC (Medium Access Control) sublayer, and a physical (PHY: Physical) layer.

  Also, the transmitting side device (mobile station UE or radio base station eNB) performs RLC processing, MAC processing, and PHY processing on the data to be transmitted in order, and then transmits the data as a radio signal in the radio unit. It is configured.

  On the other hand, the receiving side device (mobile station UE or radio base station eNB) extracts transmitted data by sequentially performing PHY processing, MAC processing, and RLC processing on the radio signal received by the radio unit. Is configured to do.

  Here, the data to be transmitted includes user data (U-plane data) generated by an application used by the user, RRC (Radio Resource Control) signaling used for control of the mobile communication system, NAS (Non Access Stratum) signaling, etc. Control data (C plane data).

  Further, an RLC retransmission control process is performed between the RLC sublayer of the transmission side apparatus and the RLC sublayer of the reception side apparatus, and between the MAC sublayer of the transmission side apparatus and the MAC sublayer of the reception side apparatus. In the configuration, HARQ (Hybrid Automatic Repeat Request) retransmission control processing (MAC retransmission control processing) is performed.

  Here, the RLC retransmission control process in the conventional mobile communication system will be described with reference to FIG.

  As illustrated in FIG. 5, in step S1001, the RLC sublayer of the transmission side apparatus transmits RLC-data-PDU # 1. Here, since the RLC sublayer of the transmission side device does not request STATUS-PDU (delivery confirmation information), “0” is set in the “Poll” field (delivery confirmation information request value) of RLC-data-PDU # 1. .

  In step S1002, the RLC sublayer of the transmission side apparatus transmits RLC-data-PDU # 2. Here, since the RLC sublayer of the transmission side device requests STATUS-PDU, “1” is set in the “Poll” field of RLC-data-PDU # 2.

In step S1003, the RLC sublayer of the reception-side apparatus receives RLC-data-PDU # 2 in which “1” is set in the “Poll” field, so RLC-data-PDU # 1 and RLC-data-PDU # 2 are received. STATUS-PDU (acknowledgment information) is transmitted.
RLC specification of IMT-2000: 3GPP TS 25.322 V6.9.0 (2006-09) LTE Stage2 Specification: 3GPP TS 36.300 V8.0.0 (2007-03)

  Here, in the LTE mobile communication system, the RLC sublayer of the transmission side apparatus divides the RLC-data-PDU according to the communication state of the radio link when retransmitting the RLC-data-PDU, An RLC-data-Sub-PDU is generated.

  In the example of FIG. 6, the RLC sublayer of the transmission side apparatus divides the RLC-data-PDU (SN = X) into three RLC-data-Sub-PDUs #A to #C at the first retransmission, At the time of the second retransmission, the three RLC-data-Sub-PDUs #A to #C are transferred to the three RLC-data-Sub-PDUs # A1 to # A3, # B1 to # B3, and # C1 to # C3, respectively. It is divided.

  Specifically, as illustrated in FIG. 7, the RLC sublayer of the transmission side device divides the entire RLC-data-PDU # 1 including the header portion, the extension header portion, and the payload portion, and RLC-data-Sub. -Insert into the payload part of PDU # 1 and # 2. A header portion is added to RLC-data-Sub-PDUs # 1 and # 2.

  Here, as shown in FIG. 7, in the conventional communication system, in the RLC-data-Sub-PDU # 1 and # 2, a “Poll” field (header part) is provided separately from the RLC-data-PDU # 1. ) Is added, and the condition for requesting STATUS-PDU (acknowledgment information) (setting “1” in the “Poll” field) is predetermined, but “Poll” The necessity of setting “1” in the field changes depending on the elapsed time in the transmission side apparatus, the transmission state of the RLC-data-PDU, the reception state of the STATUS-PDU (delivery confirmation information), and the like, and thus the RLC-data-PDU. At the transmission timing of # 1, even though it is necessary to request STATUS-PDU (acknowledgment information), RLC-data-S constituting RLC-data-PDU # 1 It may not be necessary to request STATUS-PDU (acknowledgment information) at the transmission timing of ub-PDUs # 1 and # 2, and in such a case, the RLC sublayer of the receiving-side apparatus may receive the RLC-data-Sub-PDU. Since RLC-data-PDU # 1 is reconstructed from # 1 and # 2, and “1” is set in the “Poll” field of RLC-data-PDU # 1, unnecessary STATUS-PDU (delivery (Confirmation information) is transmitted and radio resources cannot be used efficiently.

  Therefore, the present invention has been made in view of the above-described problems. When an RLC-data-Sub-PDU is transmitted, the RLC-data-PDU configured by the RLC-data-Sub-PDU is used. By ignoring the value of the “Poll” field assigned to the ID, it is possible to avoid unnecessary transmission of STATUS-PDU (acknowledgment information), thereby enabling the use of radio resources efficiently. It is an object to provide a transmission method and a receiving side device.

  A first feature of the present invention is a delivery confirmation information transmission method in which a reception side device transmits delivery confirmation information for a packet from a transmission side device, wherein the transmission side device The first packet transmitted at the time of initial transmission according to the communication status of the first link to generate and transmit a plurality of second packets, and the second packet received by the receiving device Transmitting acknowledgment information for the packet from the transmission side device in response to a delivery confirmation information request value included in the header portion of the packet, wherein the reception side device receives from the received second packet When the first packet is reconstructed, the delivery confirmation information for the packet from the transmission side device is not transmitted regardless of the delivery confirmation information request value included in the header portion of the first packet. The gist.

  A second feature of the present invention is a reception side device configured to transmit delivery confirmation information for a packet from a transmission side device, wherein the transmission side device communicates with the reception side device during retransmission. Included in the header portion of the received second packet when the first packet transmitted at the time of initial transmission is divided to generate a plurality of second packets and transmitted according to the wireless link communication status between In response to the delivery confirmation information request value, it is configured to transmit delivery confirmation information for the packet from the transmission side device, and when the first packet is reconstructed from the received second packet, The gist is that it is configured not to transmit the delivery confirmation information for the packet from the transmitting side device in accordance with the delivery confirmation information request value included in the header portion of the first packet.

  As described above, according to the present invention, when an RLC-data-Sub-PDU is transmitted, it is added to the RLC-data-PDU constituted by the RLC-data-Sub-PDU. By ignoring the value of the “Poll” field, unnecessary transmission of STATUS-PDU (delivery confirmation information) is avoided, thereby enabling the radio resource to be used efficiently and the reception side information transmission method and reception side apparatus. Can be provided.

(Configuration of mobile communication system according to the first embodiment of the present invention)
The configuration of the mobile communication system according to the first embodiment of the present invention will be described with reference to FIGS.

  In the present embodiment, as shown in FIG. 1, a mobile communication system having an LTE / SAE (System Architecture Evolution) architecture, which is being standardized by 3GPP, will be described as an example. The present invention is not limited to such a mobile communication system, but can be applied to a mobile communication system having other architecture.

  With reference to FIG. 2, a functional configuration of an RLC sublayer in Acknowledge mode (AM) (hereinafter, RLC sublayer) will be described.

  Note that some or all of the functions (modules) constituting the RLC sublayer shown in FIG. 2 may be realized by hardware or software on the IC chip.

  For example, a function (module) that constitutes a MAC sublayer and a physical layer that are generally simple and require high-speed processing on an IC chip is realized by hardware, and RLC that is generally required to perform complicated processing The functions (modules) constituting the sublayer may be configured to be realized by software.

  Further, the function (module) constituting the physical layer, the function (module) constituting the MAC sublayer, and the function (module) constituting the RLC sublayer may be realized on the same IC chip, or may be different from each other. It may be realized on an IC chip.

  Hereinafter, an example of the configuration of the RLC sublayer in the mobile communication system according to the present embodiment will be described with reference to FIG.

  As shown in FIG. 2, the RLC sublayer includes an RLC-SDU buffer 11, a new transmission buffer 12, a division and integration processing unit 13, an ACK waiting buffer 14, a retransmission buffer 15, an RLC-PDU transmission unit 16, Re-division processing unit 17, RLC-PDU transmission unit 18, RLC-control-PDU generation unit 19, RLC-control-PDU buffer 20, demultiplexing unit 31, order correction buffer 32, and reconstruction buffer 33 And an RLC-SDU reconstructing unit 34.

  The RLC-SDU buffer 11 is configured to store the RLC-SDU received from the upper layer.

  The new transmission buffer 12 is configured to copy and store the RLC-SDU stored in the RLC-SDU buffer 11.

  When the data integration opportunity is notified from the MAC sublayer, the division integration processing unit 13 performs division processing or integration processing on the RLC-SDU (or a part thereof) stored in the new transmission buffer 12, An RLC-data-PDU having a maximum size within the range of the allowable transmission data amount notified from the MAC sublayer is generated.

  The division integration processing unit 13 is configured to transmit the generated RLC-data-PDU to the RLC-PDU transmission unit 16 and store it in the ACK waiting buffer 14.

  The ACK waiting buffer 14 is an RLC-data-PDU from the division integration processing unit 13, an RLC-data-PDU or RLC-data-Sub-PDU from the retransmission waiting buffer 15, or an RLC- It is configured to store a data-Sub-PDU.

  FIG. 3 shows a format example of RLC-data-PDU used in the mobile communication system according to this embodiment, and FIG. 4 shows a format of RLC-data-Sub-PDU used in the mobile communication system according to this embodiment. An example is shown.

  As shown in FIG. 3, the header part of the RLC-data-PDU includes a “Type” field, a “Poll” field, an “Align” field, an “Ext” field, an “SN” field, and an “LI” field. Field.

  Also, as shown in FIG. 4, the header portion of the RLC-data-Sub-PDU includes a “Type” field, a “Poll” field, an “LSF (Last Segment Flag)” field, an “SN” field, And an “SO (Segment Offset)” field.

  The “Type” field is a field indicating the type of RLC-PDU. In the “Type” field, for example, RLC-data-PDU, RLC-data-Sub-PDU, RLC-control-PCU, or the like can be set as the type of RLC-PDU.

  The “Poll” field is a field including a value (delivery confirmation information request value) indicating whether or not the RLC sublayer of the reception side apparatus is prompted to transmit STATUS-PDU.

  The “Align” field indicates whether the first byte of the RLC-data-PDU is the first byte of the RLC-SDU and whether the last byte of the RLC-data-PDU is the last byte of the RLC-data-SDU. This is a field indicating whether or not.

  The “Ext” field is a field indicating whether an extension header follows the header portion of the RLC-data-PDU.

  The “SN” field indicates the sequence number of the RLC-data-PDU when included in the RLC-data-PDU, and indicates the RLC-data-Sub when included in the RLC-data-Sub-PDU. -A field indicating the sequence number of the RLC-data-PDU to which the PDU relates.

  The “LI” field is a field indicating the position of the last byte of the RLC-SDU in the “Payload” portion in the RLC-data-PDU.

  The “LSF” field is a field indicating whether or not the RLC-data-Sub-PDU is the last RLC-data-Sub-PDU in the related RLC-data-PDU.

  The “SO” field indicates the first byte of the RLC-data-SUB-PDU to which the first byte of the “Payload” portion of the RLC-data-Sub-PDU relates to the RLC-data-Sub-PDU. It is a field.

  The Ack waiting buffer 14 determines whether or not retransmission is necessary for the stored RLC-data-PDU or RLC-data-Sub-PDU, and determines whether the retransmission is necessary. The RLC-data-Sub-PDU is configured to be transmitted to the retransmission buffer 15.

  Here, for example, when the ACK waiting buffer 14 receives a STATUS-PDU (NACK) from the RLC sublayer of the receiving side device and a NACK from the MAC sublayer, the stored RLC-data-PDU or RLC- It is determined that it is necessary to retransmit the data-Sub-PDU.

  The retransmission buffer 15 is configured to store RLC-data-PDU and RLC-data-Sub-PDU from the Ack waiting buffer 14.

  When the data transmission opportunity is notified from the MAC sublayer, the RLC-PDU transmission unit 16 transmits the RLC-data-PDU transmitted from the division integration processing unit 13 and the RLC-data-PDU stored in the retransmission buffer 15. Are transmitted to the MAC sublayer.

  Here, the RLC-PDU transmission unit 16 assigns an RLC-control-PDU (STATUS-PDU or the like) stored in the RLC-control-PDU buffer 20 to the RLC-data-PDU to be transmitted. May be configured to generate and transmit an RLC-data-PDU-piggybacked-control-PDU.

  The re-division processing unit 17 determines one RLC-data stored in the retransmission buffer 15 according to the communication state of the radio link, specifically, according to the allowable transmission data amount notified from the MAC sublayer. -PDU or RLC-data-Sub-PDU is divided to generate a plurality of RLC-data-Sub-PDUs, that is, RLC-data-PDU stored in retransmission buffer 15 or The RLC-data-Sub-PDU is configured to perform subdivision processing.

  In the example of FIG. 6, the re-division processing unit 17 divides the RLC-data-PDU (SN = X) into three RLC-data-Sub-PDUs #A to #C at the time of the first retransmission. At the time of the second retransmission, the three RLC-data-Sub-PDUs #A to #C are divided into three RLC-data-Sub-PDUs # A1 to # A3, # B1 to # B3, and # C1 to # C3, respectively. is doing.

  Specifically, as shown in FIG. 7, the re-segmentation processing unit 17 divides the entire RLC-data-PDU # 1 including the header portion, the extension header portion, and the payload portion, and RLC-data-Sub- It is inserted into the payload part of PDU # 1 and # 2. A header portion is added to RLC-data-Sub-PDUs # 1 and # 2.

  Since the header portion of RLC-data-PDU # 1 includes a setting value at the time of initial transmission, not only the header portion of RLC-data-PDU # 1, but also RLC-data-Sub-PDU. The “Poll” field is also set in the header portions of # 1 and # 2.

  However, in this case, as will be described later, the RLC sublayer (RLC-control-PDU generation unit 19) of the receiving-side apparatus “Poll” set in the header part of RLC-data-Sub-PDU # 1 and # 2. ”Field is configured to generate STATUS-PDU, and“ Poll ”field value set in the header part of RLC-data-PDU # 1 is configured to be ignored. .

  The RLC-PDU transmission unit 18 is configured to transmit the RLC-data-Sub-PDU subjected to the re-division processing by the re-division processing unit 17 to the MAC sub-layer when the data transmission opportunity is notified from the MAC sub-layer. Has been.

  Here, the RLC-PDU transmission unit 18 adds an RLC-control-PDU (STATUS-PDU, etc.) stored in the RLC-control-PDU buffer 20 to the RLC-data-Sub-PDU to be transmitted. By doing so, the RLC-data-Sub-PDU-piggybacked-control-PDU may be generated and transmitted.

  The RLC-control-PDU generation unit 19 is configured to generate a STATUS-PDU (ACK / NACK) in response to the notification from the order correction buffer 32.

  For example, when an RLC-data-PDU or RLC-data-Sub-PDU in which “1” is set in the “Poll” field is received, the RLC-control-PDU generation unit 19 receives a STATUS-PDU (ACK / NACK).

  However, even when an RLC-data-PDU in which “1” is set in the “Poll” field is received, the RLC-control-PDU generation unit 19 converts the RLC-data-PDU into the RLC-data-PDU. In the case of being constructed from Sub-PDU, STATUS-PDU (ACK / NACK) is not generated.

  The RLC-control-PDU buffer 20 is configured to store the RLC-control-PDU generated by the RLC-control-PDU generation unit 19.

  The demultiplexer 31 extracts the STATUS-PDU from the RLC-PDU received from the MAC sublayer, transfers it to the ACK waiting buffer 14, and extracts the RLC-data-PDU and the RLC-data-Sub-PDU. The data is transferred to the order correction buffer 32.

  The order correction buffer 32 is configured to perform order correction processing on the stored RLC-data-PDU (or RLC-data-Sub-PDU).

  Specifically, the order correction buffer 32 is configured to store RLC-data-PDU (in-sequence) stored in the order of sequence numbers in the reconstruction buffer 33.

  On the other hand, the order correction buffer 32 performs a loss detection process on the RLC-data-PDU using the order correction timer for RLC-data-PDUs (out-of-sequence) that are not stored in the order of the sequence numbers, and is not received. When a loss for the RLC-data-PDU is detected, the RLC-control-PDU generation unit 19 is notified to that effect.

  When the RLC-data-PDU can be constructed from the stored RLC-data-Sub-PDU, the order correction buffer 32 is configured to construct the RLC-data-PDU.

  When the RLC-SDU can be constructed from the RLC-data-PDU stored in the reconstruction buffer 33, the RLC-SDU reconstruction unit 34 constructs the RLC-SDU and configures the upper layer Configured to send to.

(Operations and effects of the mobile communication system according to the first embodiment of the present invention)
According to the mobile communication system according to the first embodiment of the present invention, even when “1” is set in the “Poll” field assigned to the RLC-data-PDU, the RLC-data -If the PDU has been reconstructed by multiple RLC-data-Sub-PDUs, the unnecessary STATUS-PDU is ignored by ignoring the value of the "Poll" field and not generating a STATUS-PDU. Can be avoided and radio resources can be used efficiently.

  Although the present invention has been described in detail using the above-described embodiments, it is obvious to those skilled in the art that the present invention is not limited to the embodiments described in this specification. The present invention can be implemented as modified and changed modes without departing from the spirit and scope of the present invention defined by the description of the scope of claims. Therefore, the description of the present specification is for illustrative purposes and does not have any limiting meaning to the present invention.

It is a figure which shows the protocol layer structure in the radio | wireless access network of the mobile communication system which concerns on the 1st Embodiment of this invention. FIG. 3 is a functional block diagram of an RLC sublayer in the mobile station and the radio base station according to the first embodiment of the present invention. It is a figure which shows an example of the format of RLC-data-PDU produced | generated by the RLC sublayer in the mobile station and radio | wireless base station which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the format of RLC-data-Sub-PDU produced | generated by the RLC sublayer in the mobile station and radio | wireless base station which concerns on the 1st Embodiment of this invention. It is a sequence diagram which shows operation | movement of the mobile communication system of a LTE system. It is a figure for demonstrating the re-division process performed in the RLC sublayer in the mobile communication system of a LTE system. It is a figure for demonstrating the re-division process performed in the RLC sublayer in the mobile communication system of a LTE system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... RLC-SDU buffer 12 ... New transmission buffer 13 ... Division integration processing unit 14 ... ACK waiting buffer 15 ... Retransmission buffer 16, 18 ... RLC-PDU transmission unit 17 ... Re-division processing unit 19 ... RLC-control-PDU generation unit 20 ... RLC-control-PDU buffer 31 ... Demultiplexing unit 32 ... Order correction buffer 33 ... Reconstruction buffer 34 ... RLC-SDU reconstruction unit

Claims (2)

A reception confirmation information transmission method in which a reception side device transmits delivery confirmation information for a packet from a transmission side device,
A step of generating and transmitting a plurality of second packets by dividing the first packet transmitted at the time of initial transmission according to a communication state of a radio link with the reception side device during retransmission When,
The receiving side device has a step of transmitting delivery confirmation information for the packet from the transmitting side device in accordance with a delivery confirmation information request value included in a header portion of the received second packet;
When the receiving side device reconstructs the first packet from the received second packet, the receiving side device, regardless of the delivery confirmation information request value included in the header portion of the first packet, The delivery confirmation information transmitting method characterized by not transmitting the delivery confirmation information for the packet. A receiving side device configured to send acknowledgment information for a packet from a sending side device,
When the transmission side device generates a plurality of second packets by dividing the first packet transmitted during the initial transmission according to the communication status of the radio link with the reception side device during retransmission In response to the delivery confirmation information request value included in the received header portion of the second packet, the delivery confirmation information for the packet from the transmission side device is transmitted.
When the first packet is reconstructed from the received second packet, the delivery confirmation information for the packet from the transmission side device regardless of the delivery confirmation information request value included in the header portion of the first packet The receiving side device is configured not to transmit.

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