JP4778071B2 - Wireless communication system, wireless base station, and wireless communication method - Google Patents

Description

  The present invention relates to a wireless communication system, a wireless base station, and a wireless communication method using wireless communication.

3GPP (3rd Generation
Partnership Project) systems include W-CDMA (Wideband Code Division Multiple Access) systems and HSDPA (High
A Speed Downlink Packet Access) system and a HSUPA (High Speed Uplink Packet Access) system have been studied and specified (for example, Non-Patent Documents 1, 2, 3, and 4 below). In addition, E3G (Evolved
3G) Systems are also being studied. FIGS. 1 to 3 show configuration examples of a W-CDMA system, an HSDPA system, an HSUPA system (hereinafter, these systems are collectively referred to as “HSPA system”), and an E3G system, respectively.

  One of the features of the HSPA system is that the modulation method and the coding method are variable according to the radio wave condition. As a result, the speed of data communication can be increased.

  In addition, unlike the W-CDMA system, the HSPA system does not perform diversity handover in which handover is performed without disconnecting the connection between the base station and the terminal, and temporarily disconnects from the handover source base station. Then, a hard handover (Hard Hand Over) is performed to reconnect to the handover destination base station.

  Next, a configuration example of the network side (infrastructure side) of the conventional W-CDMA system and HSPA system is shown in FIGS. 4 and 5 (for example, described in Non-Patent Documents 1 to 4 below), and the E3G system FIG. 6 shows a configuration example of FIG. 6, and FIG. 7 shows a configuration example of terminals in each system.

As shown in FIG. 4, in a W-CDMA system, a radio network controller (RNC) 10 includes a PDCP (Packet Data Convergence Protocol) unit 12, an RLC (Radio Radio Control).
Link Control) unit 13, MAC (Media Access Control) unit 14, and radio link control unit (RRC: Radio Resource)
Control) 15. On the other hand, the radio base stations (Node_B) 20 and 30 include a signal processing (BB: Base Band) unit 22. The PDCP unit 12, the RLC unit 13, and the MAC unit 14 generate individual packets and transfer them to the units 12 and the like. Generation of these packets and the like are controlled by the wireless line control unit 15.

  FIG. 5 shows the infrastructure side configuration in the HSPA system. Compared with FIG. 4, the radio base stations (Node_B) 20 and 30 include the MAC-hs / MAC-es unit 17, and a part of the functions of the radio control station 10 exists in the radio base stations 20 and 30. ing.

  Further, as shown in FIG. 6, the E3G system has an RLC unit 13, a MAC unit 14, and a radio network controller RRC unit 15 on the radio base station (eNode_B) 51 and 52 side.

  As described above, the functions performed in the radio control station 10 of the host device in the W-CDMA system are gradually performed in the subordinate radio base stations 20, 30, 51, and 52 in the HSPA system and the E3G system. This speeds up communication by causing the packet creation to be performed on the side closer to the terminal 60.

  As shown in FIG. 7, the terminal 60 includes a PDCP unit 42 to a BB unit 48.

  FIG. 8 shows the HSUPA system, and FIG. 9 shows the HSDPA system. As shown in FIG. 8, in the HSUPA system, the data unit when output from the PDCP unit 42 in the terminal 60 to the RLC unit 43 is RLC SDU (PDCP PDU).

  The RLC unit 43 divides the RLC SDU into, for example, four RLC SDUs, adds a header to the divided RLC SDU, and outputs the RLC PDU to the MAC-es unit 46 inside the terminal 60 as an RLC PDU.

  The MAC-es unit 46 divides one RLC PDU into eight, for example, and outputs the divided RLC PDUs to the MAC-e unit 47 as MAC-es SDUs.

  The MAC-e unit 47 adds a header to the MAC-es SDU and outputs it to the signal processing unit 48 as a MAC-e PDU. The signal processing unit 48 encodes and modulates the MAC-e PDU as transmission data, and transmits the encoded data to the base stations (Node_B) 20 and 30. At this time, HARQ (Hybrid Automatic Repeat reQuest) control is performed to transmit to the base stations 20 and 30 and to store the transmission data in a buffer. As described above, the terminal 60 creates four RLC PDUs from one RLC SDU and eight MAC PDUs from one RLC PDU (for example, Non-Patent Document 5 below).

  The base stations 20 and 30 create MAC-e PDUs from the received data, and transmit the MAC-e PDUs to the radio control station 10 that is a host device. In the radio control station 10, the MAC-es unit 16 transmits to the upper RLC unit 13 when eight MAC-es SDUs are prepared.

  The RLC unit 13 collects eight MAC-es SDUs to create one RLC PDU, and when four RLC PDUs are gathered, the four RLC PDUs are grouped to create one RLC SDU, and the upper PDCP unit 12 Send to.

  The radio control station 10 can reproduce the RLC SDU created by the terminal 60.

  FIG. 9 is an example of data flow and packet creation in the HSDPA system. One RLC SDU in the radio control station 10 is divided into four RLC PDUs as going down, and further one RLC PDU is divided into eight MAC-d PDUs. Then, the radio base stations 20 and 30 create a transmission packet and transmit it to the terminal 60. At this time, HARQ control is performed, and transmission data is stored in the buffers of the radio base stations 20 and 30.

  When the terminal 60 completes eight MAC-d PDUs, the terminal 60 outputs the MAC-d PDUs in a lower order, and creates an RLC PDU by combining them. Further, when four RLC PDUs are prepared, they are output to the lower order, and RLC SDUs are generated by combining them.

  FIG. 10 shows an uplink (uplink) data flow and packet creation example in the E3G system. Also in this case, as in FIG. 8, the RLC SDU generated by the terminal 60 is divided into four RLC PDUs and eight MAC PDUs toward the higher level, and is transmitted as radio base stations (eNode_B) 51 and 52 as transmission packets. Sent to.

  In the radio base stations 51 and 52, when eight MAC PDUs are prepared, one RLC PDU is created, and when four RLC PDUs are prepared, it is transmitted to the upper apparatus (MME / UPE) 50. One RLC SDU is created from the RLC PDU. Packet integration and division are performed in substantially the same manner as in the example of FIG.

FIG. 11 illustrates a downlink (downlink) data flow and an example of packet creation in the E3G system. As in FIG. 9, packet integration and division are performed.
3GPP TS25.321V5.12.0 3GPP TS25.321V6.10.0 (especially the configuration of MAC-d, MAC-hs, MAC-e, MAC-es is shown in Fig.4.2.4.1 on page 19) 3GPP TS25.322V5.13.0 3GPP TS25.322V6.9.0 3GPP R3.018V0.6.0_6.8.4.3.2

  As described above, in the case of the HSPA system and the E3G system, for example, if eight MAC PDUs are not prepared, an RLC PDU cannot be created. Further, for example, if four RLC PDUs are not prepared, an RLC SDU can be selected. It cannot be created.

  FIG. 12 is a diagram illustrating an example of processing in the MAC unit 44 of the terminal 60 or the MAC unit 14 of the radio base stations 51 and 52 in the E3G system. The number indicates the sequence number of the MAC PDU.

  Considering the uplink direction, MAC PDUs with sequence numbers “1” to “8” are transmitted to the upper RLC unit 13 because eight MAC PDUs are arranged. However, the sequence number “12” is being retransmitted by the retransmission control. In this case, if the “12” MAC PDU is not delivered even after a certain time has elapsed, this MAC PDU is discarded together with the MAC PDUs “9” to “16” already delivered, for example. FIG. 13 shows an example of processing in the RLC unit 43 of the terminal 60. When four RLC SDUs are prepared, it is transmitted to the host device 10.

When the terminal 60 performs handover in a state where the MAC PDU is not delivered, the radio base station 52 that is the handover destination transmits the MAC PDUs having sequence numbers “9” to “16” to the terminal 60 in order to prevent data loss. Have a new transmission. For example, when one MAC PDU is not delivered, 31 transmitted MAC PDUs may be retransmitted to the handover target radio base station 52 (for example, all retransmissions from sequence numbers “9” to “40”). To do). In such a case, the handover source radio base station 51 cannot transfer the RLC SDU to the host device 10 or the handover destination base station 52. (See Figure 14)
However, it is inefficient to retransmit the MAC PDU already delivered from the terminal 60 to the handover source radio base station 51 in this way from the terminal 60 to the handover destination radio base station 52. Transmission of duplicate MAC PDUs requires extra transmission time, resulting in a decrease in throughput.

  On the other hand, in the downlink direction, the MAC PDU being retransmitted remains in the handover source radio base station 51 due to the handover. The remaining data (hereinafter referred to as “residual data”) needs to be transferred to the handover destination radio base station 52, but the terminal 60 prevents the data loss of the MAC PDU being retransmitted to the handover destination radio base station 52. Request to send At this time, the handover destination radio base station 52 requests the host apparatus 10 for data in units of RLC SDUs including the MAC PDU being retransmitted, and the handover destination radio base station 52 transmits a MAC to the terminal 60. A PDU is transmitted.

  Therefore, in the downlink direction, the MAC PDU that has already been transmitted from the handover source radio base station 51 to the terminal 60 is transmitted from the handover destination radio base station 52 to the terminal 60. The transmission of the MAC PDU causes a decrease in throughput. Due to the decrease in throughput, for example, when moving images are transmitted in real time, the moving images are displayed on the terminal 60 side in a state of dropping frames, which also affects the service.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a wireless communication system, a wireless base station, and a wireless communication that improve throughput even when handover is performed during retransmission control. It is to provide a method.

  In order to achieve the above object, according to an embodiment of the present invention, when radio communication is performed between a first radio base station and a terminal, the first radio base station is replaced by handover. In a radio communication system in which radio communication is performed between a second radio base station and the terminal, the first radio base station receives transmission packets remaining in the first radio base station due to the handover. When transferring to the second radio base station, the transfer unit of the transmission packet transmitted from the terminal to the first radio base station is divided, and the first pseudo data packet (hereinafter referred to as a dummy data packet) is divided by the transfer unit. A packet creation unit that creates a packet) and a transfer unit that forwards the created first dummy packet to the second radio base station. 1 Dami A dummy packet receiving unit that receives a packet; and a transmission packet receiving unit that requests the terminal to transmit the remaining transmission packet from the received first dummy packet and receives the transmission packet from the terminal. It is characterized by that.

  In order to achieve the above object, according to another embodiment of the present invention, in a radio base station that performs radio communication with a terminal, when a handover is executed by the terminal, transmission packets remaining after the handover are transmitted. A packet generation unit that divides a transfer unit of the transmission packet transmitted from the terminal and generates a first dummy packet in the transfer unit when transferring to a handover destination radio base station; And a transfer unit that transfers one dummy packet to the handover destination radio base station.

  Furthermore, in order to achieve the above object, according to another embodiment of the present invention, when wireless communication is performed between the first radio base station and the terminal, the first radio base is performed by handover. In a radio communication method in a radio communication system in which radio communication is performed between a second radio base station and the terminal instead of a station, in the first radio base station, the handover to the first radio base station by the handover When transferring the remaining transmission packet to the second radio base station, a transfer unit of the transmission packet transmitted from the terminal to the first radio base station is divided, and a first dummy is used in the transfer unit. A packet is created, the created first dummy packet is transferred to the second radio base station, the first radio packet is received at the second radio base station, and the received first dummy packet is received. Of the transmission request of the transmission packet said residual from the dummy packet requests to the terminal, and wherein the receiving the transmission packet from the terminal.

  According to the present invention, it is possible to provide a radio communication system, a radio base station, and a radio communication method capable of improving throughput even when handover is performed during retransmission control.

FIG. 1 is a diagram illustrating a configuration example of a W-CDMA system. FIG. 2 is a diagram illustrating a configuration example of the HSPA system. FIG. 3 is a diagram illustrating a configuration example of the E3G system. FIG. 4 is a diagram illustrating a configuration example of the infrastructure side of W-CDMA. FIG. 5 is a diagram illustrating a configuration example of the HSPA infrastructure side. FIG. 6 is a diagram illustrating a configuration example of the E3G infrastructure side. FIG. 7 is a diagram illustrating a configuration example of a terminal. FIG. 8 is a diagram showing a data flow and a packet creation example. FIG. 9 is a diagram showing a data flow and a packet creation example. FIG. 10 is a diagram showing a data flow and a packet creation example. FIG. 11 is a diagram showing a data flow and a packet creation example. FIG. 12 is a diagram illustrating an example of transmission to a higher level of a MAC PDU. FIG. 13 is a diagram illustrating an example of transmission of RLC PDU to the upper level. FIG. 14 is a diagram showing an example of RLC SDU transfer in the E3G system. FIG. 15 is a diagram illustrating an example of a data configuration. FIG. 16 is a diagram illustrating an example of a data configuration. FIG. 17 is a diagram showing the concept of transfer. FIG. 18 is a diagram showing the concept of transfer. FIG. 19 is a diagram illustrating an example of a dummy MAC PDU0 type. FIG. 20 is a diagram illustrating an example of a dummy MAC PDU1 type. FIG. 21 is a diagram showing an example of a dummy MAC PD2 type. FIG. 22 is a diagram showing an example of residual data. FIG. 23 is a diagram illustrating an example of RLC SDU and the like. FIG. 24 is a diagram illustrating an example of a transfer RLC SDU or the like. FIG. 25 is a diagram illustrating an example of RLC SDU and the like. FIG. 26 is a diagram illustrating an example of a transfer RLC SDU or the like. FIG. 27 is a diagram illustrating an example of RLC SDU and the like. FIG. 28 is a diagram illustrating an example of transfer RLC SDU and the like. FIG. 29 is a diagram illustrating an example of residual data. FIG. 30 is a diagram illustrating an example of RLC SDU and the like. FIG. 31 is a diagram illustrating an example of a transfer RLC SDU or the like. FIG. 32 is a diagram illustrating an example of RLC SDU and the like. FIG. 33 is a diagram illustrating an example of the transfer RLC SDU. FIG. 34 is a diagram illustrating an example of a transfer MAC PDU0 type. FIG. 35 is a diagram illustrating an example of a transfer MAC PDU1 type. FIG. 36 is a diagram showing an example of residual data. FIG. 37 is a diagram illustrating an example of RLC SDU and the like. FIG. 38 is a diagram illustrating an example of a transfer RLC SDU or the like. FIG. 39 is a diagram illustrating an example of RLC SDU and the like. FIG. 40 is a diagram illustrating an example of a transfer RLC SDU or the like. FIG. 41 is a diagram illustrating an example of residual data. FIG. 42 is a diagram illustrating an example of RLC SDU and the like. FIG. 43 is a diagram illustrating an example of transfer RLC SDU and the like. FIG. 44 is a diagram illustrating an example of RLC SDU and the like. FIG. 45 is a diagram illustrating an example of a transfer RLC SDU or the like. FIG. 46 is a diagram illustrating a configuration example of the E3G system. FIG. 47 is a diagram illustrating a configuration example of a transfer source wireless base station. FIG. 48 is a diagram illustrating a configuration example of a transfer destination radio base station. FIG. 49 is a diagram illustrating a configuration example of MME / UPE. FIG. 50 is a diagram illustrating a configuration example of a terminal. FIG. 51 is a diagram showing an example of a processing sequence. FIG. 52 is a diagram illustrating a configuration example of a transfer source radio base station. FIG. 53 is a diagram illustrating a configuration example of a transfer destination radio base station. FIG. 54 is a diagram illustrating a configuration example of a terminal. FIG. 55 is a diagram showing an example of a processing sequence. FIG. 56 is a diagram showing an example of RLC SDU and the like. FIG. 57 is a diagram illustrating an example of a transfer RLC SDU or the like. FIG. 58 is a diagram illustrating a configuration example of a transfer source radio base station. FIG. 59 is a diagram illustrating a configuration example of a transfer destination radio base station. FIG. 60 is a diagram showing an example of a processing sequence. FIG. 61 is a diagram illustrating a configuration example of a transfer source radio base station. FIG. 62 is a diagram illustrating a configuration example of a transfer destination radio base station. FIG. 63 is a diagram illustrating a configuration example of a terminal. FIG. 64 is a diagram showing an example of a processing sequence. FIG. 65 is a diagram illustrating a configuration example of a transfer source radio base station. FIG. 66 is a diagram illustrating a configuration example of a transfer destination radio base station. FIG. 67 is a diagram illustrating a configuration example of a terminal. FIG. 68 is a diagram showing an example of a processing sequence. FIG. 69 is a diagram illustrating an example of RLC SDU and the like. FIG. 70 is a diagram illustrating an example of a transfer RLC SDU or the like. FIG. 71 is a diagram illustrating a configuration example of a transfer source radio base station. FIG. 72 is a diagram illustrating a configuration example of a transfer destination radio base station. FIG. 73 is a diagram showing an example of a processing sequence. FIG. 74 is a diagram showing an example of RLC SDU and the like. FIG. 75 is a diagram illustrating an example of RLC SDU and the like.

Explanation of symbols

11: MME / UPE 21: Transfer source radio base station (eNode B)
31: Transfer destination radio base station (eNode B) 40: Terminal 214: Error confirmation unit 218: Retransmission control unit 219: Temporary storage unit 220: Packet creation unit 223: Dummy packet creation unit 225: Transfer packet creation unit 233: Dummy packet / Packet configuration control unit 234: transmission / transfer packet configuration control unit 235: transmission packet creation unit 236: transmission / transfer configuration information creation unit 250: HARQ temporary storage unit 251: HARQ control unit 252: transmission / transfer MAC PDU configuration control unit 253: Transmission MAC PDU creation unit 254: Transmission / transfer RLC PDU configuration control unit 255: Transmission RLC PDU creation unit 258: Transmission / transfer RLC SDU configuration control unit 259: Transmission RLC SDU creation unit 260: Transfer MAC PDU creation unit 261: Transfer RLC PDU creation unit 262: Transfer RLC S U creation unit 266: transmission / transfer packet configuration information creation unit 270: HARQ control unit 271: HARQ temporary storage unit 272: transfer MAC PDU creation unit 273: transmission / transfer MAC PDU configuration control unit 274: transfer RLC PDU creation unit 275: Transmission / transfer RLC PDU configuration control unit 276: Transfer RLC SDU creation unit 277: Transmission / transfer RLC SDU configuration control unit 284: Transmission / transfer configuration information creation unit 314: Error check unit 318: Retransmission control unit 319: Temporary storage unit 322 : Dummy packet identification unit 323: transfer packet configuration control unit 324: dummy packet configuration control unit 325: transmission / transfer configuration information extraction unit 326: transmission packet creation unit 327: packet creation unit 340: HARQ control unit 341: HARQ temporary storage unit 342: RLC SDU identification unit 343: Transfer RLC SDU configuration control unit 344: RLC PDU identification unit 345: Transfer RLC PDU configuration control unit 346: MAC PDU identification unit 347: Transfer MAC PDU configuration control unit 365: Transfer packet identification unit 366: Transfer packet configuration control unit 367: Dummy packet configuration Control unit 375: HARQ control unit 376: HARQ temporary storage unit 377: Transfer MAC PDU configuration control unit 378: Transfer RLC PDU configuration control unit 379: Transfer RLC SDU configuration control unit 384: RLC SDU identification unit 385: RLC PDU identification unit 386 : MAC PDU identification unit 416: Retransmission control unit 417: Transmission / transfer configuration information extraction unit

  The best mode for carrying out the present invention will be described below.

  First, Example 1 will be described. In the first embodiment, an example in the uplink direction (from the terminal to the radio base station) will be described.

  FIG. 15 shows an example of the data structure of RLC SDU, RLC PDU, and MAC PDU. As shown in FIG. 15, consider the following example. That is, among the MAC PDUs included in the RLC PDU sequence number “7”, sequence numbers “9” to “11” have been delivered from the terminal to the radio base station. The MAC PDU with the sequence number “12” is being retransmitted by retransmission control. In addition, it is assumed that the MAC PDU with the sequence number “13” has been delivered, and that after “14” has not been received (the terminal has not transmitted the MAC PDU to the radio base station). For this reason, the RLC PDU with the sequence number “7” cannot be transmitted to the upper layer, and the RLC SDU with the sequence number “21” cannot be transmitted (or cannot be transferred). RLC SDUs that remain without being transmitted and MAC PDUs included in the RLC SDUs are referred to as residual data.

  Consider a case where the terminal performs handover in such a state. The handover source radio base station needs to transmit data (residual data) to the handover destination radio base station in order to prevent data loss. Conventionally, when one MAC PDU is being retransmitted, the RLC SDU cannot be configured, and the terminal newly transmits an RLC SDU including the MAC PDU being retransmitted to the handover destination radio base station.

  17 and 18 are diagrams illustrating an example of transfer in the first embodiment. In the first embodiment, delivered MAC PDUs with sequence numbers “0” to “11” (of the MAC PDUs transmitted from the terminal to the radio base station, the radio base station confirmed the delivery (ACK was returned). B) Combine MAC PDUs into one RLC PDU, retransmit the MAC PDU with sequence number “12” as one RLC PDU, and deliver delivered MAC PDUs with sequence numbers “13” to “16” Combined into one RLC PDU.

  Then, as shown in FIG. 18, RLC SDUs in which the number of RLC PDUs is changed are created from the created RLC PDUs. For example, from one RLC PDU to one RLC SDU. The RLC SDU composed of the delivered MAC PDU is transmitted to the MME / UPE 11 that is the host device. As a result, the handover source radio base station can notify the MME / UPE 11 of the delivery confirmation.

  On the other hand, RLC SDUs composed of MAC PDUs whose delivery confirmation has not been taken, such as during retransmission (hereinafter referred to as “undelivered MAC PDU”), are transferred to the handover destination radio base station. Residual data is transferred to the handover destination radio base station. The handover destination radio base station requests the terminal to transmit a MAC PDU whose delivery has not been confirmed, and the MAC PDU is transmitted from the terminal. As a result, since the handover destination radio base station can request the terminal to transmit only the transferred MAC PDU, it is possible to improve the throughput without transmitting the duplicate MAC PDU to the terminal. Further, since the delivered MAC PDU is not transferred to the handover destination radio base station, the amount of data transfer between the radio base stations can be reduced.

  Here, RLC SDU composed of undelivered MAC PDU will be described. Assuming that the MAC PDU transmitted from the terminal has not been confirmed for delivery, it is not transmitted from the terminal and is not received by the handover source radio base station, and “unreceived” MAC PDU is retransmitted or transmitted from the terminal. There are two types of MAC PDUs that are currently “resending” (or “sending”). In order to create RLC SDUs from such MAC PDUs, in the first embodiment, three types of dummy MAC PDUs shown in FIGS. 19 to 21 are created. By using this pseudo MAC PDU (hereinafter referred to as a dummy MAC PDU), an RLC PDU can be created, and further an RLC SDU can be created.

  FIG. 19 is a “dummy MAC PDU0 type”, which is a “formal existence” dummy MAC PDU in which no data is inserted. Since no data is inserted, the RLC SDU is not actually transferred. However, MAC PDU, RLC PDU, RLC SDU sequence number (SN), data length, etc. may be transferred.

  FIG. 20 is a dummy MAC PDU called a dummy MAC PDU1 type, which is configured by data of a specific pattern (for example, all “0”, “1”, etc.). It is necessary to notify in advance that a MAC PDU including data of such a pattern between wireless base stations and terminals is a dummy MAC PDU.

  FIG. 21 is an example of a dummy MAC PDU type, which is an example of using a data being retransmitted including an error as it is to obtain a dummy MAC PDU.

  In the following embodiments including the first embodiment, RLC PDUs configured with dummy MAC PDUs are referred to as transfer RLC PDUs, and RLC SDUs configured with transfer RLC PDUs are referred to as transfer RLC SDUs.

  Next, an example of RLC SDU in the first embodiment will be described with reference to FIGS.

  First, FIG. 22 shows an example of residual data remaining in the handover source radio base station, FIG. 23 shows an example of the configuration of the RLC SDU, and FIG. 24 shows an example of the transfer RLC SDU using the dummy MAC PDU0 type. It is. In FIG. 22 and the like, the upper part is an example of RLC SDU, the middle part is RLC PDU, and the lower part is an example of MAC PDU.

  As shown in FIG. 22, MAC PDUs with sequence numbers “9” to “11” have been delivered, MAC PDUs with sequence number “12” are being retransmitted, and sequence numbers “13” and after are not received. is there.

  In the first embodiment, an RLC SDU (hereinafter referred to as “transmission RLC SDU”) composed of a delivered MAC PDU is transmitted to the MME / UPE 11 which is a higher-level device, and the transfer RLC SDU is transferred to the handover destination radio base station. Therefore, the structure of the RLC SDU is changed.

  Therefore, as shown in FIG. 23, one RLC PDU with the sequence number “7” is created from the MAC PDUs with the delivered sequence numbers “9” to “11”, and the sequence number “23” is created from this RLC PDU. 'RLC SDU (Transmission RLC SDU).

  Also, an RLC PDU of sequence number “8” is created from MAC PDUs of sequence numbers “12” to “16” that have not been delivered, and an RLC SDU (transfer RLC SDU of sequence number “24”) is created from this RLC PDU. ).

  It should be noted that RLC SDUs with sequence numbers “21” and “22” are created from RLC PDUs with sequence numbers “5” and “6”, which are composed of MAC PDUs for which delivery has been confirmed.

  Then, as shown in FIG. 24, a dummy MAC PDU0 type (FIG. 19) is created from the retransmitting MAC PDU of sequence number “12” and the unreceived MAC PDUs of “13” to “16”. A transfer RLC SDU composed of a dummy MAC PDU0 type is created. However, since it is of type 0, the transfer RLC SDU is not transferred to the handover destination radio base station, but configuration information indicating that the RLC SDU is configured, the data length, the sequence number, etc. are transferred as shown in FIG. The

  FIGS. 25 and 26 are examples in which a transfer RLC SDU is configured with a dummy MAC PDU1 type (see FIG. 20) for a MAC PDU that has not been delivered, although the structure of the RLC SDU is similarly changed. As shown in FIG. 26, a dummy MAC PDU using dummy data is configured from the MAC PDU being retransmitted (sequence number “12”) and the unreceived MAC PDU (sequence numbers “13” to “16”), and transferred. Create an RLC SDU. This transfer RLC SDU is transferred to the handover destination radio base station. On the other hand, the transmission RLC SDU (sequence number “23”) composed of the delivered data is transmitted to the MME / UPE 11.

  FIGS. 27 and 28 similarly change the structure of the RLC SDU. The undelivered MAC PDU is divided into “unreceived” MAC PDUs and “retransmitting (or transmitting)” MAC PDUs. In this example, a dummy MAC PDU1 type is used for “unreceived” MAC PDUs, and a dummy MAC PDU2 type is used for “under resending” MAC PDUs (see FIG. 21). With respect to the MAC PDU being retransmitted, since the data being retransmitted is transferred to the handover destination radio base station as it is, retransmission can be continued using the data being retransmitted. In all the embodiments described below, the transfer to the handover destination radio base station may be performed in units of RLC SDUs or RLC PDUs, but will be described as a typical transfer in units of RLC SDUs.

  29 to 45 will be described as other embodiments.

  Next, the configuration and operation of the first embodiment will be described. In the following description, for ease of understanding, the description will be made as a packet, a transfer packet, etc. without taking out a MAC PDU or the like specifically.

  46 is a configuration example of an E3G system that is the overall system of the first embodiment, FIG. 47 is a configuration example of a transfer source radio base station that is a handover source, and FIG. 48 is a configuration example of a transfer destination radio base station that is a handover destination. 49 shows an example of the configuration of MME / UPE, FIG. 50 shows an example of the configuration of the terminal, and FIG. 51 shows an example of the processing sequence.

  As shown in FIG. 46, the E3G system includes an MME / UPE 11, a transfer source radio base station (eNode_B) 21, a handover destination transfer destination radio base station (eNode_B) 31, and a terminal (UE) 40. . The internal configuration of the MME / UPE 11 or the like indicates functional blocks, and the description of each block is omitted because it has been described in the related art.

  FIG. 47 is a diagram illustrating a specific configuration example of the transfer source wireless base station 21. As illustrated in FIG. As shown in the figure, the transfer source radio base station 21 includes a reception radio unit 211, a demodulation unit 212, a decoding unit 213, an error confirmation unit 214, a received electric field strength information extraction unit 215, and a handover control unit 216. A retransmission control unit 218, a temporary storage unit 219, a packet creation unit 220, a transfer control unit 222, a dummy packet creation unit 223, a transfer packet creation unit 225, an ACK / NACK creation unit, and a scheduler unit 228. An uplink transmission control information creation unit 229, an encoding unit 230, a modulation unit 231, a transmission radio unit 232, a dummy packet / packet configuration control unit 233, a transmission / transfer packet configuration control unit 234, and a transmission packet A creation unit 235 and a transmission / transfer configuration information creation unit 236 are provided.

  FIG. 48 is a diagram illustrating a specific configuration example of the transfer destination radio base station 31. As shown in the figure, the transfer destination radio base station 31 includes a reception radio unit 311, a demodulation unit 312, a decoding unit 313, a handover control unit 316, a transfer control unit 320, and a transmission / transfer packet identification unit 321. A dummy packet identification unit 322, a transfer packet configuration control unit 323, a dummy packet configuration control unit 324, a transmission / transfer configuration information extraction unit 325, a transmission packet creation unit 326, a packet creation unit 327, and a scheduler unit 328, an uplink transmission control information creation unit 329, an ACK / NACK creation unit 330, an encoding unit 331, a modulation unit 332, and a transmission radio unit 333.

  FIG. 49 is a diagram illustrating a specific configuration example of the MME / UPE 11. As shown in the figure, the MME / UPE 11 includes a PDCP unit 12, and the PDDCP unit 12 includes a ROHC (Robust Header Compression) unit 121, an encryption unit 122, and a PDCP PDU creation unit 123.

  FIG. 50 is a diagram illustrating a specific configuration example of the terminal 40. As shown in the figure, the terminal 40 includes a transmission packet (PDCP PDU) reception unit 401, a transmission packet creation unit 402, an encoding unit 403, a modulation unit 404, a transmission radio unit 405, and reception field strength measurement. Unit 406, reception field strength information creation unit 408, reception radio unit 409, demodulation unit 410, decoding unit 411, uplink transmission control information extraction unit 412, handover control information extraction unit 413, and handover control unit 414 An ACK / NACK extraction unit 415, a retransmission control unit 416, and a transmission / transfer configuration information extraction unit 417.

  The E3G system configured as described above operates as follows. That is, the transfer packet reception unit 401 of the terminal 40 receives, for example, image data captured by the camera of the terminal 40, and the transmission packet creation unit 402 creates a transmission packet from the received image data. The transmission packet is encoded and modulated by the encoding unit 403 and the modulation unit 404, converted to a predetermined frequency by the transmission radio unit 405, and transmitted to the transfer source radio base station 21 via the antenna.

  The transmission packet transmitted from the terminal 40 is received by the reception radio unit 211 of the transfer source radio base station 21, demodulated and decoded via the demodulation unit 212 and the decoding unit 213, and output to the error confirmation unit 214. The error confirmation unit 214 determines whether or not there is an error in the data based on the CRC code for the decoded transmission packet, and outputs the determination result to the retransmission control unit 218 via the temporary storage unit 219. The transmission packet data from the decoding unit 213 is temporarily stored in the temporary storage unit 219.

  On the other hand, the reception field strength measurement unit 406 of the terminal 40 measures the reception field strength from the radio base stations 21 and 31, and the reception field strength information creation unit 408 creates reception field strength information. The information is transmitted from the terminal 40 to the transfer source radio base station 21 via the encoding unit 403, the modulation unit 404, and the transmission radio unit 405.

  The reception field strength information is output to the reception field strength information extraction unit 215 via the reception radio unit 211, the demodulation unit 212, and the decoding unit 213. Then, the handover control unit 216 determines the handover of the terminal 40 from the received electric field strength information. When the handover control unit 216 determines that the handover of the terminal 40 has been executed, the handover control unit 216 outputs a control signal to each unit as shown by a two-dot chain line in FIG. Each part operates.

  The retransmission control unit 218 of the transfer source wireless base station 21 confirms the configuration of the remaining transmission packet stored in the temporary storage unit 219, and whether the transmission packet decoded from the decoding unit 213 is a packet being retransmitted or an unreceived packet. The packet is identified as a packet or a delivered packet, and the result is notified to the dummy packet / packet configuration control unit 233.

  The dummy packet / packet configuration control unit 233 divides the transmission packet stored in the temporary storage unit 219 into packets each having a smaller data length, and each packet is a “delivered” packet or an “undelivered” packet. And “delivered” packets are output to the packet creation unit 220, and “undelivered” packets are output to the dummy packet creation unit 223.

  That is, when the dummy packet / packet configuration control unit 233 obtains an identification result indicating a delivered packet from the retransmission control unit 218, the dummy packet / packet configuration control unit 233 outputs the corresponding packet stored in the temporary storage unit 219 to the packet creation unit 220. When an identification result indicating a packet being retransmitted or not transmitted is obtained from the retransmission control unit 218, the corresponding packet stored in the temporary storage unit 219 is output to the dummy packet creation unit 223.

  Further, the dummy packet / packet configuration control unit 233 creates packet configuration information and dummy packet configuration information. The packet configuration information includes accompanying information such as a sequence number (SN) and a data length of the packet created by the packet creation unit 220 and the dummy packet creation unit 223. In addition to these pieces of information, the dummy packet configuration information includes information indicating a dummy packet, information indicating which dummy packet is a plurality of types of dummy packets, information indicating a dummy bit pattern, and the like. included. The packet creation unit 220 and the dummy packet creation unit 223 create a packet and the like based on the packet configuration information and the dummy packet configuration information.

  The dummy packet creation unit 223 creates a dummy packet for a packet being retransmitted or an unreceived packet, and outputs the dummy packet to the transfer packet creation unit 225. The packet creation unit 220 creates a normal packet for the delivered packet and outputs it to the transmission packet creation unit 235. The dummy packet / packet configuration control unit 233 outputs packet configuration information and dummy packet configuration information to the transmission / transfer packet configuration control unit 234.

  The transmission / transfer packet configuration control unit 234 creates transfer packet configuration information from the dummy packet configuration information. The transfer packet configuration information includes dummy packet configuration information, SN of the transfer packet, and the like, for example, information indicating which transfer packet the packet is included in. In addition, the transmission / transfer packet configuration control unit 234 creates transmission packet configuration information from the packet configuration information. The transmission packet configuration information includes packet configuration information, SN of the transmission packet, and the like.

  The transfer packet creation unit 225 creates a transfer packet from one or a plurality of dummy packets based on the transfer packet configuration information. The transmission packet creation unit 235 creates a transmission packet from one or more packets.

  The created transfer packet is transferred from the transfer control unit 222 to the handover destination radio base station 31. On the other hand, the transmission packet is transmitted from the transfer control unit 222 to the MME / UPE 11 that is the host device. Delivery confirmation is performed to the MME / UPE 11 by transmission of the transmission packet.

  Also, the transmission / transfer configuration information creation unit 236 performs transmission configuration information and transfer configuration information (both of which are related to the changed packet configuration) based on the transmission packet configuration information and the transfer packet configuration information from the transmission / transfer packet configuration control unit 234. , Configuration, SN, data length, etc.). Here, the configuration is information indicating that the transfer packet is configured with two dummy packets (SN = 30, 31), for example.

  Since the structure of the “forwarding packet” is changed by changing the number of packets included in the “forwarding packet”, the transfer configuration information includes information indicating that this has been changed. On the other hand, regarding the “transmission packet”, the SN or the like may be changed with the change of the structure of the “transfer packet”, and the transmission configuration information includes information regarding the packet configuration with the change.

  The transfer configuration information is notified to the MME / UPE 11, the handover destination radio base station 31, and the terminal 40. Transmission configuration information is also notified in the same manner. These pieces of configuration information are notified at the same time or in advance with transmission of transfer packets and transmission packets. In addition, when notifying the transfer configuration information and the transmission configuration information to the terminal 40, it is notified via the encoding unit 230 or the like.

  The retransmission control unit 218 instructs the ACK / NACK creation unit 226 to create “NACK” when there is “error” from the signal indicating that there is no error from the error confirmation unit 214. In the case of “no error”, an instruction is given to create “ACK”. The ACK / NACK creation unit 226 outputs the created signal indicating “NACK” or “ACK” to the encoding unit 230, is encoded, and is transmitted to the terminal 40 via the modulation unit 231 and the transmission radio unit 232. The

  Further, the scheduler unit 228 receives information (for example, CQI) indicating the radio channel quality from the terminal 40, determines “which terminal transmits the packet” based on the information, and performs transmission control on the terminal 40. It instructs the uplink transmission control information creation unit 229 to create information. The uplink transmission control information creation unit 229 creates uplink transmission control information indicating a modulation method, an encoding method, and the like for the determined terminal 40. The created uplink transmission control information is transmitted to the terminal 40 via the encoding unit 230 and the like, and the terminal 40 transmits a transmission packet to the transfer source radio base station 21 based on this control information.

  In the handover destination radio base station 31, the transfer control unit 320 receives the transfer packet, and the transmission / transfer configuration information extraction unit 325 extracts the transfer configuration information. The transfer packet is output to the transmission / transfer packet identification unit 321 to identify whether it is a transmission packet from the MME / UPE 11 or a transfer packet.

  For example, the transfer packet configuration information is notified from the transmission / transfer configuration information extraction unit 325 to the transfer packet configuration control unit 323, and the transfer packet configuration control unit 323 transmits the transfer packet identification information included in the transfer packet configuration information. The packet identification unit 321 is notified. Based on this information, the transmission / transfer packet identification unit 321 identifies whether the packet is a transfer packet.

  The transmission / transfer packet identification unit 321 outputs the transfer packet to the dummy packet identification unit 322 and discards the transmission packet.

  The dummy packet identification unit 322 divides the transfer packet into packets and identifies whether the packet is a dummy packet. The identification is performed by the dummy packet configuration control unit 324 based on the dummy packet identification information notified from the transmission / transfer configuration information extraction unit 325. The dummy packet identification unit 322 discards the dummy packet and outputs other packets to the temporary storage unit 319 for temporary storage.

  Then, retransmission control section 318 requests terminal 40 to transmit a packet corresponding to the dummy packet based on the dummy packet identification information from dummy packet configuration control section 324. In this case, since it is a “undelivered” dummy packet, the delivery confirmation has not been taken, and the retransmission control unit 318 requests a new transmission. Therefore, it is not necessary to request transmission of the target packet, such as specifying the SN of the packet.

  A request for new transmission from the retransmission control unit 318 is notified to the scheduler unit 328, selects the terminal 40, the uplink transmission control information creating unit 329 and the uplink transmission control information such as the encoding method, the encoding unit 331, etc. Is encoded and transmitted to the terminal 40.

  In the terminal 40, transmission configuration information and transfer configuration information are notified in advance from the transfer source radio base station 21, decoded by the reception radio unit 409 and the like, and extracted by the transmission / transfer configuration information extraction unit 417. The transmission / transfer configuration information extraction unit 417 extracts and holds a transmission packet configuration and a transfer packet configuration, and further a packet configuration and a dummy packet configuration from the transmission configuration information and the like. Further, the transmission / transfer configuration information extraction unit 417 confirms an “undelivered” packet from the dummy packet configuration information.

  The terminal 40 receives and decodes the uplink transmission control information from the transfer destination radio base station 31 by the reception radio unit 409 and the like, and the uplink transmission control information extraction unit 412 extracts the transmitted uplink transmission control information. The uplink transmission control information extraction unit 412 outputs this information to the encoding unit 403, the modulation unit, and the transmission radio unit 405, and the encoding unit 403 and the like are subjected to the encoding scheme specified by the transmission control information. Then, based on the uplink transmission control information, the transmission packet creation unit 402 creates a new transmission packet to be transmitted to the transfer destination radio base station 31, and transmits the transmission packet via the encoding unit 403 and the like.

  In the transfer destination radio base station 31, the transmission packet is decoded via the reception radio unit 311, etc., the error check unit 314 is checked for errors, and the received transmission packet is stored in the temporary storage unit 319. .

  If there is an error, the retransmission control unit 318 requests the scheduler unit 328 to transmit a transmission packet to the terminal 40 again. This process is repeated until there are no errors.

  If there is no error, retransmission control section 318 instructs packet creation section 327 to create a packet from the data of the transmission packet stored in temporary storage section 319. The created packets are grouped into one or more at the transmission packet creation unit 326 to create a transmission packet and transmitted to the MME / UPE 11 via the transfer control unit 320.

  FIG. 51 is a diagram illustrating an example of a processing sequence according to the first embodiment. Since this is a duplicate description, a brief description will be given. First, when the transfer source wireless base station (Node_B1) 21 detects a handover (S10), it confirms whether the transmission packet transmitted from the terminal 40 is “delivered” or “undelivered”. (S11).

  The transfer source radio base station 21 examines the configuration of the transmission / transfer packet (S12), notifies the MME / UPE 11 of configuration information indicating the determined transfer packet and the configuration of the transfer packet (S13), and the configuration information. To the handover destination radio base station (Node_B2) 31 and the terminal (UE1) 40.

  Next, the transfer source wireless base station 21 creates a packet for the “delivered” packet (S15), creates a transmission packet from the packet (S16), and transmits the transmission packet to the MME / UPE 11 (S17).

  Further, the transfer source wireless base station 21 creates a dummy packet for the “undelivered” packet (S18), and creates a transfer packet (S20).

  When the handover is performed (S21), the transfer source radio base station 21 transfers the transfer packet to the transfer destination radio base station 31 that is the handover destination (S22).

  The terminal 40 newly transmits a packet corresponding to the dummy packet based on the request from the transfer destination radio base station 31 (S24).

  As described above, in the first embodiment, the transmitted transmission packet is transmitted to a higher level (MME / UPE 11 or the like), and the undelivered transmission packet is transferred to the handover destination transfer destination radio base station 31. For this purpose, the structure of the transmission packet transmitted from the transfer source radio base station 21 as the handover source to the MME / UPE 11 and the transfer packet transferred to the transfer destination radio base station 31 are changed. Accordingly, in the past, new transmission of a packet including a packet whose delivery has been confirmed is performed from the transfer destination radio base station 31 to the terminal 40, but it corresponds to the dummy packet transferred from the transfer source radio base station 21. Only the packet to be transmitted is transmitted from the terminal 40. Therefore, the transmission time can be shortened and the throughput can be improved as compared with the conventional case.

  Next, Example 2 will be described. The second embodiment is an example in which the packet is specifically a MAC PDU, RLC PDU, or RLC SDU as compared to the first embodiment. Further, a dummy MAC PDU0 type (FIG. 19) or a dummy MAC PDU1 type (FIG. 20) is used for a “undelivered” MAC PDU from the terminal 40 to the transfer source wireless base station 21, and a structure such as an RLC SDU is provided. It is an example to change (FIGS. 23 to 25).

  46 is a configuration example of the E3G system that is the overall system of the second embodiment, FIG. 49 is a configuration example of the MME / UPE 11 that is the host device, FIG. 52 is a configuration example of the transfer source radio base station that is the handover source, and FIG. Is a configuration example of a transfer destination radio base station that is a handover destination, FIG. 54 is a diagram illustrating a configuration example of a terminal, and FIG. 55 is a diagram illustrating an example of a processing sequence.

  As shown in FIG. 52, the transfer source radio base station 21 is configured to specifically create a MAC PDU, an RLC PDU, and an RLC SDU. The transfer source radio base station 21 according to the second embodiment newly adds a HARQ temporary storage unit 250, a HARQ control unit 251, and a transmission / transfer to the transfer source radio base station 21 (FIG. 48) according to the first embodiment. MAC PDU configuration control unit 252, transmission MAC PDU creation unit 253, transmission / transfer RLC PDU configuration control unit 254, transmission RLC PDU creation unit 255, ARQ temporary storage unit 256, ARQ control unit 257, transmission / transfer A transfer RLC SDU configuration control unit 258, a transmission RLC SDU creation unit 259, a transfer MAC PDU creation unit 260, a transfer RLC PDU creation unit 261, and a transfer RLC SDU creation unit 262 are provided.

  Also, as shown in FIG. 53, the transfer destination radio base station 31 also newly includes a HARQ control unit 340, a HARQ temporary storage unit 341, an RLC SDU identification unit 342, a transfer RLC SDU configuration control unit 343, RLC PDU identification unit 344, transfer RLC PDU configuration control unit 345, MAC PDU identification unit 346, transfer MAC PDU configuration control unit 347, transmission packet information creation unit 348, RLC PDU creation unit 349, and RLC SDU creation Unit 350, ARQ temporary storage unit 351, and ARQ control unit 352.

  Further, as shown in FIG. 54, also in the terminal 40, an RLC SDU (PDCP PDU) receiving unit 420, an RLC PDU creating unit 421, an ARQ temporary storage unit 422, a MAC PDU creating unit 423, and an HARQ are newly added. Temporary storage unit 424, ARQ control unit 425, ARQ ACK / NACK extraction unit 426, and transmission / transfer configuration information extraction unit 427 are provided.

  Each unit 11 of the E3G system configured as described above operates as follows. That is, the transmission packet creation unit 403 of the terminal 40 creates a transmission packet and transmits it to the transfer source radio base station 21 via the encoding unit 403 and the like. This transmission packet is transmitted in units of MAC PDUs.

  The transfer source radio base station 21 outputs the transmitted MAC PDU to the error confirmation unit 214 via the reception radio unit 211 or the like. The error check unit 214 detects an error in the MAC PDU and outputs “error” or “no error” information to the HARQ control unit 251. The error confirmation unit 214 outputs the MAC PDU to the HARQ temporary storage unit 250 regardless of whether there is an error or the like.

  When the handover control unit 216 detects the handover of the terminal 40, the following operation is performed.

  The HARQ control unit 251 detects the type of the MAC PDU transmitted from the terminal 40 based on the information from the error confirmation unit 214. That is, if the received MAC PDU is “error”, the HARQ control unit 251 determines that the MAC PDU is an “undelivered” MAC PDU, and if it is “no error”, the MAC PDU is “delivered”. judge. The HARQ control unit 251 outputs this result to the transmission / transfer MAC PDU configuration control unit 252.

  Note that “undelivered” can be classified into retransmission, transmission, and unreception, but in the second embodiment, “undelivered” is not distinguished.

  Although the MAC PDU transmitted from the terminal 40 is stored in the HARQ temporary storage unit 250, there is no MAC PDU sufficient to configure an RLC SDU that is a transmission unit to the MME / UPE 11 that is the host device. It cannot be transmitted to the MME / UPE 11. As a result, MAC PDU data remains. This is called residual data. Hereinafter, an RLC SDU configured with residual data is referred to as an old RLC SDU, and an RLC PDU configuring the old RLC SDU is referred to as an old RLC PDU.

  The transmission / transfer MAC PDU configuration control unit 252 divides the old RLC SDU and the old RLC PDU stored in the HARQ temporary storage unit 250 into MAC PDU units, and creates a transmission MAC PDU when “delivered”. In the case of “undelivered”, the data is output to the forwarding MAC PDU creation unit 260. Further, the transmission / transfer MAC PDU configuration control unit 252 creates transmission MAC PDU identification information when a “delivered” result is obtained, and creates transfer MAC PDU identification information when “not delivered”. The transmission MAC PDU identification information includes a MAC PDU sequence number (SN), a data length, information indicating a delivered MAC PDU (or information indicating that it is a transmission MAC PDU), and the like. In addition to the SN, data length, and information indicating undelivered MAC PDU (information indicating that it is a transfer MAC PDU), the transfer MAC PDU identification information includes dummy packet identification information (dummy MAC PDU0 type or 1). Type). The transmission MAC PDU creation unit 253 and the transfer MAC PDU creation unit 260 create a transmission MAC PDU and a transfer MAC PDU based on the transmission MAC PDU identification information and the transfer MAC PDU identification information.

  The transfer MAC PDU creation unit 260 creates a dummy MAC PDU0 type or dummy MAC PDU1 type dummy MAC PDU (or transfer MAC PDU), and outputs the created transfer MAC PDU to the transfer RLC PDU creation unit 261. However, since the dummy MAC PDU0 type does not include actual data, the transfer MAC PDU creation unit 260 extracts the SN number from the transfer MAC PDU information and outputs the SN number to the transfer RLC PDU creation unit 261. A PDU is created and output.

  The transmission MAC PDU creation unit 253 creates a normal MAC PDU and outputs it to the transmission RLC PDU creation unit 255.

  Also, the transmission / transfer MAC PDU configuration control unit 252 outputs the generated transmission MAC PDU configuration information and transfer MAC PDU configuration information to the transmission / transfer RLC PDU configuration control unit 254.

  The transmission / transfer RLC PDU configuration control unit 254 determines the configuration of the transmission or transfer RLC PDU based on the transmission or transfer MAC PDU configuration information, and uses the information as the transmission or transfer RLC PDU configuration information as the transmission / transfer RLC PDU configuration information. The data is output to the SDU configuration control unit 258. For example, information such as the SN number and the number of MAC PDUs included in the transfer RLC PCU. The transmission or transfer RLC PDU configuration information also includes accompanying information of the RLC PDU (SN of the RLC PDU, data length, delivered or undelivered, transferred RLC PDU or transmitted RLC PDU, etc.).

  The transmission RLC PDU creation unit 255 creates a transmission RLC PDU from one or a plurality of transmission MAC PDUs based on the transmission RLC PDU configuration information. The transmission RLC PDU is output to the transmission RLC SDU creation unit 259.

  Also, the transfer RLC PDU creation unit 261 creates a transfer RLC PDU from one or more transfer MAC PDUs based on the transfer RLC PDU configuration information. The transfer RLC PDU is output to the transfer RLC SDU creation unit 262. However, when the transfer RLC PDU is composed of the dummy MAC PDU0 type, since the transfer RLC PDU does not include actual data, the SN of the RLC PDU is extracted from the transfer RLC PDU information, and the transfer RLC SDU creation unit 262 It is assumed that a transfer RLC PDU is created and output by

  The transmission / transfer RLC SDU configuration control unit 258 determines the configuration of the transmission RLC SDU and the transfer RLC SDU based on the transmission / transfer RLC PDU configuration information, and transmits the information as transmission / transfer RLC SDU configuration information. The data is output to the transfer configuration information creation unit 236. For example, information such as the SN number and the number of RLC PDUs included in the transfer RLC SDU. The transmission or transfer RLC SDU configuration information also includes accompanying information of the transfer RLC SDU (SN of the RLC SDU, data length, delivered or undelivered, transferred RLC SDU or transmitted RLC SDU, etc.).

  The transmission RLC SDU creation unit 259 creates a transmission RLC SDU from one or a plurality of transmission RLC PDUs based on the transmission RLC SDU configuration information. Also, the transfer RLC SDU creation unit 262 creates a transfer RLC SDU from one or more transfer RLC PDUs based on the transfer RLC SDU configuration information. However, when the transfer RLC SDU is composed of the dummy MAC PDU0 type, since the actual data is not included, the transfer RLC SDU is generated by extracting and outputting the SN of the transfer RLC SDU from the transfer RLC SDU configuration information. Will be output.

  The transfer control unit 222 transmits the transmission RLC SDU from the transmission RLC SDU creation unit 259 to the MME / UPE 11, and forwards the transfer RLC SDU from the transfer RLC SDU creation unit 262 to the handover destination transfer destination radio base station 31. To do. When the transfer RLC SDU is composed of the dummy MAC PDU0 type, the transfer RLC SDU is not actually transferred.

  The transmission / transfer configuration information creation unit 236 transmits, from the transmission / transfer RLC SDU configuration information from the transmission / transfer RLC SDU configuration control unit 258, transmission / transfer configuration information regarding the configuration of the changed transmission / transfer RLC SDU and RLC PDU. (SN, data length, etc.) are created. For example, as shown in FIG. 23, for example, one RLC PDU (SN = 8) is configured from five dummy MAC PDUs (SN = 12 to 16), and the RLC SDU (one RLC SDU ( SN = 24). The transmission or transfer configuration information includes changed configuration information.

  The transmission configuration information and the transfer configuration information are transmitted from the transmission / transfer configuration information creation unit 236 to the MME / UPE 11, the transfer destination radio base station 31, and further to the terminal 40. This is for notifying each unit of the changed configuration information. Such information needs to be transmitted at the same time or in advance when transferring the transfer RLC SDU, transmitting the transmission RLC SDU, or the like. When such information is notified to the terminal 40, it is transmitted via the encoding unit 230 or the like.

  The transfer destination radio base station 31 that is the handover destination receives the transfer RLC SDU by the transfer control unit 320 and extracts the transfer configuration information by the transmission / transfer configuration information extraction unit 325. The extracted transfer configuration information is output to the transfer RLC SDU configuration control unit 343, the transfer RLC PDU configuration control unit 345, and the transfer MAC PDU configuration control unit 347. In each case, the transfer RLC SDU configuration information and the transfer RLC PDU are transmitted. Configuration information and transfer MAC PDU configuration information are extracted.

  The RLC SDU identification unit 342 identifies whether the RLC SDU from the transfer control unit 320 is a transfer RLC SDU. The identification is performed based on transfer RLC SDU configuration information (for example, accompanying information indicating whether the transfer RLC SDU is a transfer RLC SDU) from the transfer RLC SDU configuration control unit 343. In the case of a transfer RLC SDU, the RLC SDU identification unit 342 divides the RLC SDU into transfer RLC PDU units according to the transfer RLC SDU configuration information, and outputs the RLC SDU to the RLC PDU identification unit 344. For example, as shown in FIG. 23, a transfer RLC SDU with SN = 24 is divided into transfer RLC PDUs with SN = 8.

  In the RLC PDU identification unit 344, the RLC PDU is transferred based on the transfer RLC PDU configuration information notified from the transfer RLC PDU configuration control unit 345 (for example, accompanying information indicating whether the transfer RLC PDU or the transfer RLC PDU is transferred). In the case of a transfer RLC PDU, it is divided into MAC PDU units according to the transfer RLC PDU configuration information and output to the MAC PDU identification unit 346. For example, as shown in FIG. 23, a transfer RLC PDU with SN = 8 is divided into 5 transfer MAC PDUs with SN = 12-16.

  The MAC PDU identification unit 346 identifies whether the MAC PDU is a transfer MAC PDU based on transfer MAC PDU configuration information (for example, information indicating whether it is a dummy MAC PDU) from the transfer MAC PDU configuration control unit 347. In the case of a transfer MAC PDU, the HARQ control unit 340 is requested to newly transmit a MAC PDU corresponding to the transfer MAC PDU.

  The HARQ control unit 340 requests the scheduler unit 328 to newly transmit a MAC PDU corresponding to the transfer MAC PDU from the terminal 40 and requests the terminal 40 to transmit a MAC PDU.

  In the case of a transfer RLC PDU or a transfer RLC SDU in which all the MAC PDUs to be configured are dummy MAC PDUs (transfer MAC PDUs), the transfer RLC SDU configuration control unit 343 identifies the transfer RLC PDU without performing the identification by the RLC SDU identification unit 342 or the like. You may make it do.

  The terminal 40 extracts the transfer configuration information and the transmission configuration information notified from the transfer source radio base station 21 by the transmission / transfer configuration information extraction unit 427, and transfers or transmits RLC SDU, transfer or transmission RLC PDU, transfer or transmission Check each configuration of the MAC PDU. The transfer configuration information includes transfer MAC PDU configuration information, and “undelivered” MAC PDUs are confirmed from the transfer MAC PDU configuration information. These pieces of information are notified to the MAC PDU creation unit 423, and the MAC PDU creation unit 423 creates a MAC PDU corresponding to the dummy MAC PDU and transmits it to the transfer destination radio base station 31.

  In the transfer destination radio base station 31, the transmitted MAC PDU is received by the reception radio unit 311 or the like, and the error check unit 314 checks whether there is an error. The HARQ control unit 340 requests the ACK / NACK creation unit 330 to create a signal corresponding to whether there is an error. Repeat until there are no errors.

  If there is no error, the MAC PDU stored in the HARQ temporary storage unit 341 is output to the ARQ temporary storage unit 351, and the RLC SDU is generated via the RLC PDU creation unit 349 and the RLC SDU creation unit 350, and transfer control is performed. The data is transmitted from the unit 320 to the MME / UPE 11 that is the host device.

  FIG. 55 is a diagram illustrating an example of a processing sequence according to the second embodiment. Since it becomes a duplicate description, it will be briefly described.

  First, when the transfer source wireless base station (Node_B1) 21 detects a handover (S30), the MAC PDU transmitted from the terminal (UE1) 40 confirms whether the delivered MAC PDU is an undelivered MAC PDU (S31). . Then, the transfer source radio base station 21 examines the configuration of the transmission RLC SDU and the transfer RLC SDU, and notifies the MME / UPE 11, the transfer destination radio base station (Node_B2) 31, and the terminal 40 as the configuration information. (S33, S34).

  Further, the transfer source radio base station 21 creates a transmission MAC PDU for the delivered MAC PDU (S35), creates a transmission RLC PDU, and further creates a transmission RLC SDU (S36, S37), and transmits it to the MME / UPE 11 ( S38).

  On the other hand, for the undelivered MAC PDU, the transfer source radio base station 21 creates a transfer MAC PDU, a transfer RLC PDU, and a transfer RLC SDU (S39 to S41). When handover is performed (S42), the transfer RLC The SDU is transferred to the transfer destination radio base station 31 (S44). Further, the transfer source wireless base station 21 requests the terminal 40 to transmit a MAC PDU corresponding to the undelivered MAC PDU, and the MAC PDU is transmitted from the terminal 40 (S45). As described above, in the second embodiment, as in the first embodiment, the transfer destination radio base station 31 that is the handover destination transmits a request to the terminal 40 only to an undelivered MAC PDU. Therefore, the transmission time can be reduced and the throughput can be improved as compared with the case of transmitting the MAC PDU including the MAC PDU for which the delivery has been confirmed.

Next, Example 3 will be described. In the second embodiment, the transmission confirmed or undelivered MAC PDUs are not combined to create a transmission or forwarding RLC PDU beyond the configuration of the old RLC PDU. That is, in the second embodiment, a transmission RLC PDU including a delivered MAC PDU and a transmission RLC PDU including an undelivered MAC PDU are divided into two RLC PDUs, one for each RLC PDU. RLC
SDU was created. In the third embodiment, one transfer or transmission RLC SDU is created from a plurality of RLC PDUs beyond the frame (configuration) of the old RLC SDU.

  Such transmission RLC SDUs and transfer RLC SDUs are created in the transmission RLC SDU creation unit 259 and the transfer RLC SDU creation unit 262 regardless of the configuration of the old RLC PDU (regardless of the number of transfer RLC PDUs and transfer RLC PDUs). That's fine.

  56 and 57 are diagrams illustrating a configuration example of the RLC SDU and a configuration example of the transfer RLC SDU using the dummy MAC PDU0 type. A transfer RLC PDU (SN = 8) is created from a retransmitted MAC PDU (SN = 12) and an unreceived MAC PDU (SN = 13 to 16), and two transfer RLC PDUs (SN = 8, 9) 1 Two forwarding RLC SDUs (SN = 22) are created. Of course, one transfer RLC SDU may be created from three or more transfer RLC PDUs, and one transfer RLC PDU may be created from three or more transfer RLC PDUs.

  In FIG. 57, the dummy MAC PDU constituting the transfer RLC SDU is of type 0, but of course it may be of type 1.

  Next, Example 4 will be described. In the fourth embodiment, the “undelivered” MAC PDU is divided into “retransmitting” and “not received”, and the “retransmitting” MAC PDU is a dummy MAC PDU using data being retransmitted. (Type 2 shown in FIG. 21) is created, and retransmission is continued at the handover destination radio base station 31.

  27 and 28 are diagrams illustrating a configuration example of the RLC SDU and a configuration example of the transfer RLC SDU. The transmission RLC SDU is created for the “delivered” MAC PDU and is transmitted to the MME / UPE 11 which is the host device, as in the second embodiment. For the MAC PDU being “retransmitted”, the data being retransmitted with an error is used as it is to form a dummy MAC PDU, one RLC PDU, and further one RLC SDU. Forward to 31. On the other hand, for the “unreceived” MAC PDU, a dummy MAC PDU 1 type is used to form an RLC PDU and further an RLC SDU, and the resultant is transferred to the transfer destination radio base station 31.

  Of course, RLC SDUs may be created using a dummy MAC PDU0 type for “unreceived” MAC PDUs.

  46 is a configuration example of the E3G system showing the entire system in the fourth embodiment, FIG. 54 is a configuration example of the terminal 40, FIG. 58 is a configuration example of the transfer source radio base station 21, and FIG. FIG. 60 is a diagram showing a configuration example, and FIG. 60 shows an example of a processing sequence.

  The configurations of the transfer source radio base station 21 and the transfer destination radio base station 31 are substantially the same as those in the second embodiment. The transfer source radio base station 21 adds a point that the HARQ control unit 251 creates and notifies the transmission / transfer MAC PDU configuration control unit 252 of retransmission information indicating the number of retransmissions, a coding rate, a modulation method, and the like. Is done. In addition, in the transfer destination radio base station 31, a point in which retransmission information is notified from the transfer MAC PDU configuration control unit 347 to the HARQ control unit 340 is added.

  Hereinafter, the operation will be described by explaining these added points.

  The MAC PDU is transmitted from the terminal 40 to the transfer source radio base station 21 and stored in the HARQ temporary storage unit 250 via the error check unit 214. When the handover control unit 216 detects a handover of the terminal 40, each unit operates.

  The HARQ control unit 251 confirms the configuration of the old RLC SDU (RLC SDU composed of residual data) stored in the HARQ temporary storage unit 250, and sets the type of the MAC PDU constituting the old RLC SDU as an error check unit. Based on the result of error confirmation from 214, identification is performed.

  When there is an error, the HARQ control unit 251 indicates that the MAC PDU is “retransmitting”, the MAC PDU is “delivered” when there is no error, and “not received” when neither error nor error is confirmed. It is identified as a MAC PDU. The HARQ control unit 251 outputs the identification result to the transmission / transfer MAC PDU configuration control unit 252.

  Further, the HARQ control unit 251 holds the number of retransmissions from the number of times that the ACK / NACK creation unit 226 is instructed to create NACK, and from the uplink transmission control information created by the uplink transmission control information creation unit 229 via the scheduler unit 228. The encoding rate and the like are held, and these pieces of information are sent as retransmission information to the transmission / transfer MAC PDU configuration control unit 252 when the handover is triggered.

  The transfer MAC PDU creation unit 260 creates a dummy MAC PDU based on the transfer MAC PDU information from the transmission / transfer MAC PDU configuration control unit 252 and the identification result from the HARQ control unit 251.

  For example, when the dummy MAC PDU type 2 is created, data constituting the MAC PDU being retransmitted including the error stored in the HARQ temporary storage unit 250 is used. The dummy MAC PDU1 type uses data of a specific pattern held in the transfer MAC PCU creation unit 260, and the dummy MAC PDU0 type does not actually create any data, and outputs SN or the like to the transfer RLC PDU creation unit 261. .

  The retransmission information generated by the HARQ control unit 251 transmits the transmission / transfer configuration information via the transmission / transfer MAC PDU configuration control unit 252, the transmission / transfer RLC PDU configuration control unit 254, and the transmission / transfer RLC SDU configuration control unit 258. The data is output to the creation unit 236. The retransmission information may be included in the transmission configuration information or the transfer configuration information and transferred from the transmission / transfer configuration information creation unit 236 to the transfer destination radio base station 31 or at a timing different from the transmission configuration information or the transfer configuration information. May be forwarded separately.

  The transmission or transfer MAC PDU configuration information and the like are substantially the same as those in the second embodiment, but, for example, identification information indicating the type of the dummy MAC PDU is included as much as the dummy MAC PDU2 type is added. Further, the accompanying information included in the transmission or transfer MAC PDU configuration information includes information for identifying whether it is “resending”, “not received”, or “delivered”.

The configuration of the RLC PDU or RLC SDU is determined by the transmission / transfer MAC PDU configuration control unit 252 or the like, and based on the determined configuration, the transfer RLC SDU creation unit 262 creates the transfer RLC SDU, and the transmission RLC SDU creation unit At 259, a transmission RLC SDU is created. The created transfer RLC SDU is transferred to the transfer destination radio base station 31, and is transferred to the transfer RLC.
The SDU is transmitted to the MME / UPE 11.

  The transmission / transfer configuration information creation unit 236 transmits the transmission configuration information and the transfer configuration information to the MME / UPE 11, the transfer destination radio base station 31, and the terminal 40, as in the second embodiment. Transmission to the terminal 40 uses the encoding unit 230 or the like.

  In the transfer destination radio base station 31 that is the handover destination, the transfer configuration information is extracted by the transmission / transfer configuration information extraction unit 325. The transmission / transfer configuration information extraction unit 325 also extracts retransmission information. The extracted transfer configuration information and retransmission information are notified to the transfer RLC SDU configuration control unit 343, the transfer RLC PDU configuration control unit 345, and the transfer MAC PDU configuration control unit 347.

  The MAC PDU identification unit 346 identifies whether it is a forwarding MAC PDU (dummy MAC PDU) from the forwarding MAC PDU configuration information, and further identifies whether it is a “retransmitting” MAC PDU.

  When the MAC PDU identifying unit 346 identifies a MAC PDU (dummy MAC PDU type 2) “during retransmission”, the MAC PDU identifying unit 346 stores the MAC PDU in the HARQ temporary storage unit 341. In addition, the transfer MAC PDU configuration control unit 347 notifies the retransmission information to the HARQ control unit 340 and continues retransmission from the terminal 40 to the transfer destination radio base station 31. What is retransmitted is a MAC PDU corresponding to a MAC PDU “in retransmission”. The HARQ control unit 340 notifies the scheduler unit 328 of retransmission, and the scheduler unit 328 requests retransmission of the MAC PDU corresponding to the terminal 40. Thereafter, the same processing as in the second embodiment is performed.

  FIG. 60 is a diagram illustrating an example of a processing sequence according to the fourth embodiment. First, when the transfer source wireless base station 21 detects a handover (S30), it confirms the type of the MAC PDU transmitted from the terminal (UE1) 40 (S31). Then, the transfer source radio base station 21 examines the configurations of the transmission RLC SDU and the transfer RLC SDU, and notifies the determined configuration information to the MME / UPE 11, the transfer destination radio base station (Node_B2) 31, and the terminal 40 (S33). , S34).

  The transfer source wireless base station 21 creates a transmission RLC SDU for the “delivered” MAC PDU and transmits it to the MME / UPE 11 (S35 to S38), and a dummy MAC PDU2 type for the “resending” MAC PDU. A dummy MAC PDU0 type or type 1 is created for the “unreceived” MAC PDU (S50 to S51). Further, the transfer source radio base station 21 creates a transfer RLC SDU from the dummy MAC PDU (S40 to S41), and when handover is performed (S42), the retransmission information and the transfer RLC SDU are transferred to the transfer destination radio base station 31. Notification and transfer (S52, S44). The retransmission information may be notified together with the configuration information notification (S33), or may be added to the header of the transfer RLC SDU.

  The transfer destination radio base station 31 makes a retransmission request to the terminal 40 (S53), and the MAC PDU corresponding to the MAC PDU “under retransmission” is retransmitted (S54). The MAC PDU corresponding to the “unreceived” MAC PDU is newly transmitted in response to a new transmission request from the transfer destination radio base station 31 (S45).

  As described above, in the fifth embodiment, as in the second embodiment and the like, only the MAC PDU being “retransmitted” and the MAC PDU “unreceived” are transmitted from the terminal 40 to the transfer destination radio base station 31. As compared with the conventional case, the throughput can be improved. In the fifth embodiment, since retransmission is continued using the retransmission information, the number of retransmissions can be reduced as compared with the second embodiment, and the throughput can be further improved.

  Next, Example 5 will be described. In the fourth embodiment, transfer RLC SDUs and the like are sequentially created according to the sequence number (SN) of the MAC PDU. However, in this fifth embodiment, transfer RLC SDUs and the like are not limited to the SN of the MAC PDU. To create.

  FIGS. 29 to 33 are diagrams illustrating examples of the transfer RLC SDU and the like according to the fifth embodiment. For example, consider the example of residual data shown in FIG. With respect to the MAC PDU transmitted from the terminal 40 to the transmission source radio base station 31, the MAC PDU of SN = 9, 11, 13 is the “delivered” MAC PDU, SN = 10, 12 is “retransmitting”, and SN = 14 ˜16 are “unreceived” MAC PDUs.

  At this time, in the example of the first embodiment, in order to comply with the MAC PDU, even if the same type of MAC PDU is present, the transmission RLC SDU is created separately. For example, one transmission RLC SDU for a MAC PDU with SN = 9, one transmission RLC SDU for a MAC PDU with SN = 10, and one transmission RLC for a MAC PDU with SN = 11 An SDU will be created.

Therefore, in the fifth embodiment, as shown in FIG. 30, the same type of MAC PDUs are combined into one RLC PDU, thereby reducing the number allocated as SN, and the number of transfer RLC SDU configuration information. To reduce the amount of processing and, as a result, reduce the transmission time and improve the throughput. In the example of FIG. 30, “delivered” MAC PDUs with SN = 9,11 are rearranged to RLC PDUs with SN = 7, and “retransmitting” MAC PDUs with SN = 10,12 are reordered into RLC PDUs with SN = 8. Rearrangement, “unreceived” MAC PDUs with SN = 14-16 are rearranged into RLC PDUs with SN = 8. RLC with SN = 7
The PDU is a transmission RLC PDU, and the RLC PDU with SN = 8 is a “non-delivery” transfer RLC PDU including “under retransmission” and “not received”.

  FIG. 31 shows an example in which a dummy MAC PDU0 type is configured for an RLC PDU with SN = 8. Of course, a dummy MAC PDU1 type may be used instead of the dummy MAC PDU0 type.

  FIG. 32 is an example of RLC SDU for the residual data of FIG. “Retransmitting” MAC PDUs are rearranged to form one RLC PDU (SN = 8), and “unreceived” MAC PDUs are rearranged to form one RLC PDU (SN = 9). In this case, the dummy MAC PDU2 type is used for the MAC PDU “in retransmission”.

  Such rearrangement is performed as follows, for example. That is, the transmission / transfer MAC PDU configuration control unit 252 of the transfer source wireless base station 21 illustrated in FIG. 52 uses the transmission MAC PDU and transfer MAC PDU from the “delivered” and “undelivered” information from the HARQ control unit 251. MAC PDUs to be used are identified, and the information is notified to the transmission / transfer RLC PDU configuration control unit 254 as transfer MAC PDU configuration information and transmission MAC PDU configuration information.

  The transmission / transfer RLC PDU configuration control unit 254 rearranges the SNs of the MAC PDU so that the same type of MAC PDU becomes one RLC PDU, and transmits the rearranged information to the transmission MAC PDU configuration information and the transfer MAC PDU configuration information. To the transmission / transfer RLC SDU configuration control unit 258.

  The transfer RLC PDU creation unit 261 creates a transfer RLC PDU based on the transfer RLC PDU configuration information including rearrangement information. The same applies to the other creation units 262 and the like. Thereafter, the process is the same as in the second embodiment until the transfer RLC SDU is transferred to the transfer destination radio base station 31.

  As shown in FIG. 53, in the transfer destination radio base station 31, the transfer MAC PDU is identified by the MAC PDU identification unit 346. Therefore, even if the SNs are rearranged, it is possible to request the terminal 40 to transmit the corresponding MAC PDU as in the second embodiment.

  As shown in FIG. 32, when RLC SDUs are created by discriminating between MAC PDUs that are “retransmitting” and MAC PDUs that are not yet received, the transfer source radio base station 21 shown in FIG. 58 and FIG. The same can be performed by the transfer destination radio base station 31.

  Next, Example 6 will be described. In the following embodiments, including the sixth embodiment, the downlink direction (direction from the radio base station to the terminal) will be described.

  Consider the example shown in FIG. MAC PDUs with SN = 9 to 11 are “delivered” to the terminal, MAC PDUs with SN = 12 are “retransmitting” to the terminal, MAC PDUs with SN = 13 are “delivered”, and MACs with SN = 14 to 16 The PDU is “not transmitted”. At this time, since the RLC PDU of SN = 7 is not in a state of MAC PDU, the RLC PDU cannot be configured. Also, an RLC SDU with SN = 21 cannot be configured because RCL PDUs are not available.

  When a handover occurs in such a state, the RLC SDU with SN = 21 remains in the handover source radio base station as residual data.

  Therefore, in the sixth embodiment, as in the first embodiment, the configuration of the RLC PDU and RLC SDU is changed, and “delivered” MAC PDUs are collected to create an RLC PDU and RLC SDU, and “undelivered” RLC PDUs and RLC SDUs are created by grouping the MAC PDUs of the two, and RLC SDUs composed of “undelivered” MAC PDUs are transferred to the handover destination transfer destination radio base station 31 (see FIGS. 17 and 18).

  The transfer destination radio base station 31 only transmits “undelivered” MAC PDUs to the terminal 40, and the transmission time is compared with the conventional case where the MAC PDU “delivered” is transmitted to the terminal 40. Can be shortened, and throughput can be improved.

  For the “undelivered” MAC PDU, the transfer source radio base station 21 creates a MAC PDU as a dummy MAC PDU, as in the first embodiment. 34 and 35 are diagrams illustrating examples of dummy MAC PDUs. In the following description, a dummy MAC PDU is a transfer MAC PDU, a transfer MAC PDU composed of “untransmitted” data that is not transmitted to the terminal 40 is a transfer MAC PDU0 type (FIG. 34), and an error message “during retransmission”. The transfer MAC PDU composed of the transmission data of the transfer MAC PDU1 type (FIG. 35).

  36 to 40 are diagrams showing examples of residual data, examples of transfer RLC SDUs, and the like. As shown in FIG. 36, MAC PDUs with SN = 9 to 11 are “delivered”, MAC PDUs with SN = 12 are “retransmitting”, and SNs 13 to 16 are “untransmitted”.

At this time, as shown in FIG. 37, the configuration of the RLC SDU or RLC PDU is changed, an RLC PDU of SN = 7 is created from the “delivered” MAC PDU (SN = 9 to 11), ”And“ unsent ”(“ undelivered ”) MAC PDUs (SN = 12 to 16), an RLC PDU with SN = 8 is created. Furthermore, for each RLC PDU with SN = 5-9, each RLC with SN = 21-25, respectively.
Create an SDU.

  FIG. 38 is a diagram illustrating a configuration example of a transfer RLC SDU using the transfer MAC PDU0 type. A transfer MAC PDU is configured using “untransmitted” data for a “undelivered” MAC PDU.

  FIG. 39 is a configuration example of another RLC SDU. In the example shown in the figure, an RLC PDU with SN = 8 is configured for a MAC PDU (SN = 12) that is “retransmitting” and a MAC PDU (SN = 13 to 16) that is not yet transmitted. , SN = 9 RLC PDUs are constructed. Separate RLC PDUs and RLC SDUs are created for “Retransmitting” and “Not transmitted”.

  FIG. 40 is a diagram illustrating a configuration example of a transfer RLC SDU using the transfer MAC PDU1 type. An RLC PDU or the like is configured with a “retransmitting” MAC PDU as a transfer MAC PDU1 type and an “untransmitted” MAC PDU as a transfer MAC PDU0 type.

  Note that the RLC SDU composed of “delivered” MAC PDUs is not transferred to the handover destination radio base station 31. For the “delivered” MAC PDU, only the information indicating “delivery confirmed” is transmitted to the host device. Therefore, a packet for transmission is not actually created, and the configuration (frame) shown in FIGS. 37 and 38 is created as configuration information. The configuration information is transmitted to the host device, the terminal, and the handover destination radio base station, as in the first embodiment.

  In the sixth embodiment, “under retransmission” and “not yet transmitted” are described as “undelivered”, and the MAC PDU of “not yet delivered” is described using the transfer MAC PDU0 type.

  Next, the configuration and operation of the sixth embodiment will be described. In the following example, in order to facilitate understanding, MAC PDUs and the like are not expressed but are referred to as packets and transfer packets.

  46 is a diagram showing an example of the overall configuration of the present system, and FIG. 49 is a diagram showing an example of the configuration of the MME / UPE 11, which is an example of the host device, as in the first embodiment. 61 is a configuration example of the transfer source radio base station 21 that is the handover source, FIG. 62 is a configuration example of the transfer destination radio base station 31 that is the handover destination, FIG. 63 is a configuration example of the terminal 40, and FIG. It is a figure which shows the example of each.

  Since FIG. 46 and FIG. 49 have been described in the first embodiment, they are omitted. As shown in FIG. 61, the transfer source radio base station 21 includes a reception radio unit 211, a demodulation unit 212, a decoding unit 213, a received electric field strength information extraction unit 215, a handover control unit 216, and a temporary storage unit 219. A packet creation unit 220, a transfer control unit 222, a dummy packet creation unit 223, a transfer packet creation unit 225, a scheduler unit 228, an encoding unit 230, a modulation unit 231, a transmission radio unit 232, An ACK / NACK extraction unit 265, a transmission / transfer packet configuration information creation unit 266, and a downlink transmission control information creation unit 267 are provided. The same components as those in the first embodiment are denoted by the same reference numerals.

  As shown in FIG. 62, the transfer destination radio base station 31 includes a reception radio unit 311, a demodulation unit 312, a decoding unit 313, a handover control unit 316, a retransmission control unit 318, a temporary storage unit 319, and a transfer Control unit 320, dummy packet identification unit 322, transmission / transfer configuration information extraction unit 325, scheduler unit 328, encoding unit 331, modulation unit 332, transmission radio unit 333, transfer packet identification unit 365, A forward packet configuration control unit 366, a dummy packet configuration control unit 367, a packet creation unit 368, a transmission packet creation unit 369, a downlink transmission control information creation unit 370, and an ACK / NACK extraction unit 371. Similarly, the same components as those in the first embodiment are denoted by the same reference numerals.

  As illustrated in FIG. 63, the terminal 40 includes an encoding unit 403, a modulation unit 404, a transmission radio unit 405, a reception radio unit 409, a demodulation unit 410, a decoding unit 411, and a downlink transmission control information extraction unit. 412, handover control information extraction unit 413, handover control unit 414, transmission / transfer configuration information extraction unit 417, error confirmation unit 430, temporary storage unit 431, retransmission control unit 432, and ACK / NACK creation unit 433.

  The E3G system configured as described above operates as follows. That is, the IP header is compressed with respect to the IP data by the ROHC unit 121 of the MME / UPE 11, and the encryption unit 122 performs encryption. The encrypted data is transferred by the PDCP PDU creation unit 123 with a header (sequence number (SN), data length, CRC, etc.) added.

  The transfer source radio base station 21 receives the transfer packet from the MME / UPE 11 by the transfer control unit 222. The transfer control unit 222 outputs the transfer packet to the packet creation unit 220. When the scheduler unit 228 permits transmission to the terminal 40, the packet creation unit 220 follows the transmission method (modulation method, coding method, data length, etc.) specified by the scheduler unit 228, and the SN, CRC, header Is added to create a transmission packet.

  The created transmission packet is encoded by the encoding unit 230, modulated by the modulation unit 231, converted to a radio frequency by the transmission radio unit 232, and transmitted to the terminal 40. The packet creation unit 220 temporarily stores the created transmission packet in the temporary storage unit 219.

  The terminal 40 receives the transfer packet from the transfer source radio base station 21 by the reception radio unit 409, converts it into a baseband signal, demodulates it by the demodulation unit 410, and decodes it by the decoding unit 411.

  Note that the downlink transmission control information created by the scheduler unit 228 in the transfer source radio base station 21 is transmitted to the terminal 40 in advance via the modulation unit 231 and the like, and the downlink transmission control information extracting unit 412 of the terminal 40 performs downlink transmission. It is assumed that control information is extracted and processing is performed from the reception radio unit 409 to the decoding unit 411 based on this information.

  The decoded transmission packet is checked for error by the error checking unit 430 and temporarily stored in the temporary storage unit 431. The result of the error checking unit 430 is notified to the retransmission control unit 432. When “no error”, the retransmission control unit 432 instructs to create an “ACK” signal, and when “error”, the retransmission control unit 432 , Instructing the generation of the “NACK” signal. Then, the created “ACK” or “NACK” signal is encoded by the encoding unit 403 or the like and transmitted to the transfer source radio base station 21.

  The transfer source radio base station 21 receives the “ACK” or “NACK” signal at the reception radio unit 211, is demodulated by the demodulation unit 212, is decoded by the decoding unit 213, and is output to the ACK / NACK extraction unit 265.

  The ACK / NACK extraction unit 265 extracts “ACK” or “NACK” and notifies the retransmission control unit 218 of the extraction result.

  When “ACK” is extracted, retransmission control section 218 deletes transmission packet data stored in temporary storage section 219. When “NACK” is extracted, the retransmission control unit 218 changes the transmission method and the like, requests the terminal 40 to retransmit the transmission packet, and retransmits the transmission packet. When retransmitted, the retransmission control section 218 updates retransmission information indicating the number of retransmissions, the coding rate, and transmission information (encoding scheme, modulation scheme, RV information, etc.) at the previous transmission.

  Consider a case where handover from the transfer source radio base station 21 to the transfer destination radio base station 31 is performed during such a series of operations.

  When the handover control unit 216 detects the occurrence of the handover of the terminal 40 from the received field strength information from the received field strength information extraction unit 215, the handover control unit 216 instructs the retransmission control unit 218, the dummy packet creation unit 223, and the like to operate.

  The retransmission control unit 218 confirms the delivery state (delivered or undelivered) of the packets constituting the old transfer packet (residual transfer packet) stored in the temporary storage unit 219. That is, the retransmission control unit 218 notifies the dummy packet / packet configuration control unit 233 of information indicating “delivered” when “ACK” is extracted, and indicates “not delivered” when “NACK” is extracted. Information is notified to the dummy packet / packet configuration control unit 233.

  The dummy packet / packet configuration control unit 233 includes a transmission packet configured with a delivery confirmation packet and an undelivered packet based on information indicating “delivered” and information indicating “undelivered”. The configuration of the old transfer packet is changed for each transfer packet. The dummy packet / packet configuration control unit 233 includes configuration information indicating the changed configuration (such as SN = 30, 31 packets as dummy packets), information for identifying whether the packet is a dummy packet, Packet configuration information and dummy packet configuration information including information (SN, data length, etc.) attached to the packet and dummy packet, and delivery information (whether it has been delivered or not delivered) are created. Packet configuration information is created for “delivered” packets, and dummy packet configuration information is created for “undelivered” packets.

  The dummy packet creation unit 223 creates a transfer MAC PDU0 type dummy packet using untransmitted data stored in the temporary storage unit 219 based on the dummy packet configuration information. Note that the “delivered” packet does not need to be transmitted from the transfer destination radio base station 31 to the terminal 40, so a packet including actual data is not created, and the configuration (frame) shown in FIG. It is only created as configuration information.

  The transmission / forwarding packet configuration control unit 234 creates transmission packet configuration information or forwarding packet configuration information based on the packet configuration information or dummy packet configuration information, respectively. The transmission packet configuration information includes information related to the configuration of the transmission packet, the SN of the transmission packet, the data length, and packet configuration information. The transfer packet configuration information includes information indicating that it is a transfer packet, information related to the configuration of the transfer packet (eg, a transfer packet is composed of dummy packets with SN = 30 and 31), the SN of the transfer packet, and the data length Further, dummy packet configuration information is also included.

  The transfer packet creation unit 225 creates a transfer packet by combining one or more dummy packets based on the transfer packet configuration information created by the transmission / transfer packet configuration control unit 234.

  The transmission / transfer packet configuration information creation unit 266 creates a transmission packet configuration information signal based on the transmission packet configuration information from the transmission / transfer packet configuration control unit 234, and transfers the transfer packet configuration information signal based on the transfer packet configuration information Create

  The transmission packet configuration information signal and the transfer packet configuration information signal are transmitted to the MME / UPE 11, the transfer destination radio base station 31, and the terminal 40, for example. Since the transmission packet information signal includes delivery information, information indicating “delivered” (information indicating that delivery confirmation has been taken) is transmitted to the MME / UPE 11. In this case, this information may be transmitted to the MME / UPE 11 separately from the transmission packet information signal. When these signals are transmitted to the terminal 40, they are transmitted via the encoding unit 230 or the like.

  On the other hand, the transfer packet created by the transfer packet creation unit 225 is transferred from the transfer control unit 222 to the transfer destination radio base station 31 that is the handover destination. Transmission and transfer of the transfer packet configuration information signal are performed prior to transfer of the transfer packet. Of course, it may be performed simultaneously with the transfer of the transfer packet.

  The transfer destination wireless base station 31 receives the transferred transfer packet by the transfer control unit 320. The transmission configuration information and the transfer configuration information are extracted by the transmission / transfer configuration information extraction unit 325.

  The transmission configuration information and the transfer configuration information extracted by the transmission / transfer configuration information extraction unit 325 are output to the transfer packet configuration control unit 366 and the dummy packet configuration control unit 367. The transfer packet configuration control unit 366 extracts the transfer packet configuration information from the transfer configuration information and outputs it to the transfer packet identification unit 365. The dummy packet configuration control unit 367 extracts the dummy packet configuration information from the transfer configuration information and outputs it to the dummy packet identification unit 322.

  The transfer packet identification unit 365 identifies whether or not the received packet is a transfer packet based on the transfer packet configuration information. Since the transfer packet configuration information includes information indicating the transfer packet, this is used.

  When the forwarding packet identifying unit 365 identifies the forwarding packet, the forwarding packet identifying unit 365 divides the forwarding packet into packets that are smaller units based on the forwarding packet configuration information, and outputs each packet to the dummy packet identifying unit 322. To do.

  The dummy packet identification unit 322 identifies whether the packet is a dummy packet based on the dummy packet configuration information. Since the dummy packet configuration information includes information indicating that it is a dummy packet, it is used.

  When the dummy packet identification unit 322 identifies the dummy packet, the dummy packet identification unit 322 stores the dummy packet in the temporary storage unit 319 via the packet creation unit 368. Alternatively, the dummy packet identification unit 322 directly stores the dummy packet in the temporary storage unit 319. Furthermore, the dummy packet identification unit 322 notifies the retransmission control unit 318 of information indicating new transmission.

  The packet creation unit 368 again creates a packet from the dummy packet and stores it in the temporary storage unit 319.

  The retransmission control unit 318 requests the scheduler unit 328 to perform a new transmission to the terminal 40 based on the new transmission information. The scheduler unit 328 instructs the downlink transmission control information creation unit 370 to create downlink transmission control information indicating a transmission method to the terminal 40, and reads data included in the dummy packet stored in the temporary storage unit 319. The transmission packet creation unit 369 creates a transmission packet, adds downlink transmission control information to the transmission packet, and causes the encoding unit 331 to output the transmission packet.

  The transmission packet is encoded by the encoding unit 331, modulated by the modulation unit 332, converted to a frequency frequency by the transmission radio unit 333, and transmitted to the terminal 40.

  In the case of the transfer MAC PDU0 type, the dummy packet includes “untransmitted” data that has not been transmitted from the transfer source radio base station 21 to the terminal 40. Therefore, if the data related to the terminal 40 is transmitted from the radio base station 31, Residual data can be transmitted to the terminal 40.

  The terminal 40 receives the transmission packet by the reception wireless unit 409. The transmission packet is demodulated through the demodulator 410 and the like, and the error check unit 430 checks whether there is an error. The error confirmation unit 430 notifies the retransmission control unit 432 of the result, and the retransmission control unit 432 sends “ACK” (no error) and “NACK” (with error) to the ACK / NACK creation unit 433 depending on whether there is an error. Instruct creation. The generated “ACK” or “NACK” signal is transmitted to the transfer destination radio base station 31 via the encoding unit 403 and the like.

  The received transmission packet is temporarily stored in the temporary storage unit 431. When there is no error, the transmission packet is transmitted to a higher-level component (for example, a transmission packet creation unit) of the terminal 40.

  The transfer destination radio base station 31 extracts “ACK” or “NACK” by the ACK / NACK extraction unit 371. When receiving (extracting) “ACK”, the retransmission control unit 318 confirms delivery, sets the next dummy packet as a processing target, and when receiving “NACK”, instructs the scheduler unit 328 to perform retransmission. Thereafter, the above process is repeated.

  FIG. 64 is a diagram illustrating an example of a processing sequence according to the sixth embodiment. Briefly, first, when the transfer source wireless base station (Node_B1) 21 detects a handover (S60), it determines whether the transmission packet to the terminal 40 is “delivered” or “undelivered”. Confirm (S61).

  Then, the transfer source radio base station 21 examines the configuration of transmission and transfer packets (S62), and transmits the determined configuration to the MME / UPE 11, the transfer destination radio base station (Node_B2) 31, the terminal (UE1) 40, and the like. .

  Thereafter, the transfer source wireless base station 21 creates a configuration for the “delivered” packet (S65) and notifies the delivery confirmation (S66).

  Further, the transfer source wireless base station 21 creates a dummy packet for the “undelivered” packet (for example, transfer MAC PDU0 type) (S67), and creates a transfer packet from the dummy packet (S69).

  When handover is performed (S70), the transfer packet is transferred to the transfer destination radio base station 31 (S72).

  The transfer destination radio base station 31 confirms a packet to be newly transmitted from the dummy packet, and newly transmits the packet to the terminal 40 as a transmission packet (S74).

  As described above, in the sixth embodiment, the configurations of the delivered packet and the undelivered packet are changed, and only the undelivered packet for which the delivery confirmation has not been taken is transmitted from the handover destination radio base station 31 to the terminal 40. Therefore, the transmission time can be shortened and the throughput can be improved as compared with the conventional transmission of the packet including the packet whose delivery has been confirmed to the terminal 40.

  Next, Example 7 will be described. Although it is a downlink direction like Example 6, it is an example which makes a packet and a transfer packet concretely MAC PDU, RLC PDU, and RLC SDU. There are two types of packets, “undelivered” and “delivered”, and a dummy packet uses the transfer MAC PDU0 type.

  46 is a configuration example of the entire system, FIG. 49 is a configuration example of the MME / UPE 11 that is the host device, FIG. 65 is a configuration example of the transfer source radio base station 21, FIG. 66 is a configuration example of the transfer destination radio base station 31, and FIG. 67 shows a configuration example of the terminal, and FIG. 68 shows an example of the processing sequence.

Since FIG. 46 and FIG. 49 have been described in the first embodiment, the description thereof will be omitted. As shown in FIG. 65, the transfer source radio base station 21 newly adds a HARQ control unit 270, a HARQ temporary storage unit 271, a transfer MAC PDU to the transfer source radio base station 21 (FIG. 61) shown in the sixth embodiment. Creation unit 272, transmission / transfer MAC PDU configuration control unit 273, transfer RLC PDU creation unit 274, transmission / transfer RLC PDU configuration control unit 275, transfer RLC SDU creation unit 276, transmission / transfer RLC SDU configuration control unit 277 An ARQ control unit 278, an ARQ temporary storage unit 279, an RLC SDU (PDCP PDU) reception unit 280, and an RLC
A PDU creation unit 281, a MAC PDU creation unit 282, and a transmission packet creation unit 283 are provided.

  As shown in FIG. 66, the transfer destination radio base station 31 newly includes a HARQ control unit 375, a HARQ temporary storage unit 376, a transfer MAC PDU configuration control unit 377, a transfer RLC PDU configuration control unit 378, and a transfer RLC SDU. Configuration control unit 379, RLC PDU creation unit 380, RLC SDU creation unit 381, ARQ temporary storage unit 382, ARQ control unit 383, RLC SDU identification unit 384, RLC PDU identification unit 385, MAC PDU identification A unit 386 and a MAC PDU creation unit 387.

  As illustrated in FIG. 67, the terminal 40 newly includes a HARQ temporary storage unit 435 and a HARQ control unit 436.

  The E3G system configured as described above operates as follows. First, in the MME / UPE 11, as in the sixth embodiment, data encrypted by the ROHC unit 121 and the encryption unit 122 is created, and a PDCP PDU is created by the PDCP PDU unit 123 and transmitted.

  The transfer source radio base station 31 receives the PDCP PDU from the MME / UPE 11 as the RLC SDU at the RLC SDU (PDCP PDU) receiving unit 280.

  The RLC PDU creation unit 281 creates an RLC PDU by dividing the received RLC SDU into one or more, adds a header or the like to each RLC PDU, and outputs the RLC PDU to the MAC PDU creation unit 282.

  The MAC PDU creation unit 282 creates a MAC PDU by dividing the RLC PDU into one or more, and temporarily stores the created MAC PDU in the HARQ temporary storage unit 271.

  When transmission to the terminal 40 is permitted by the scheduler unit 228, the MAC PDU stored in the HARQ temporary storage unit 271 is read, a transmission packet is generated by the transmission packet generation unit 283, and a downlink transmission control information generation unit Along with the downlink transmission control information created at 267, the data is encoded by the encoding unit 230 or the like and transmitted to the terminal 40. The transmission packet is temporarily stored in the HARQ temporary storage unit 271.

  The terminal 40 receives the transmission packet by the reception radio unit 409 or the like, and the error check unit 430 checks whether there is an error. The result is notified to the HARQ control unit 430, and a signal corresponding to the presence or absence of an error is output from the ACK / NACK creation unit 433. The signal is encoded by the encoding unit 403 or the like and transmitted to the transfer source radio base station 21.

  The transfer source radio base station 21 receives an “ACK” or “NACK” signal by the reception radio unit 211 and the like, is extracted by the ACK / NACK extraction unit 265, and the result is notified to the HARQ control unit 270.

  When receiving (extracting) “ACK”, the HARQ control unit 270 deletes the transmission packet temporarily stored in the HARQ temporary storage unit 271. On the other hand, when receiving “NACK”, the HARQ control unit 270 instructs the scheduler unit 228 to retransmit, and the scheduler unit 228 retransmits the transmission packet stored in the HARQ temporary storage unit 271 to the terminal 40.

  Consider a case where handover is performed from the transfer source radio base station 21 to the transfer destination radio base station 31 during this series of operations.

  As in the sixth embodiment, if there is a MAC PDU that has not been acknowledged and has not been transmitted yet, that is, “resending” MAC PDU, the RLC PDU composed of this MAC PDU cannot be confirmed, and the RLC SDU is acknowledged. I can't take it. Therefore, in the HARQ temporary storage unit 271, “undelivered” MAC PDUs that have not been acknowledged and “delivered” MAC PDUs are stored as residual data (remaining). The residual data is data to be transferred to the handover destination radio base station 31 and transmitted from the radio base station 31 to the terminal 40.

  Also in the seventh embodiment, as in the sixth embodiment, the RLC SDU to be transferred to the transfer destination radio base station 31, the RLC SDU to be transmitted to the MME / UPE 11 which is the host device (actually delivery confirmation information), In order to distinguish these, the configuration of the RLC PDU or RLC SDU is changed. Then, the transfer source radio base station 21 creates a transfer MAC PDU0 type dummy packet for the “undelivered” MAC PDU and transfers it to the transfer destination radio base station 31.

  When the handover controller 216 detects the handover of the terminal 40, the HARQ controller 270 and the like execute the following operations. That is, the HARQ control unit 270 creates information indicating the delivery status of the MAC PDU (old MAC PDU) stored in the HARQ temporary storage unit 271 based on the extraction result from the ACK / NACK extraction unit 265. That is, the HARQ control unit 270 notifies the transmission / transfer MAC PDU configuration control unit 273 of “delivered” when “ACK” is received and “undelivered” when “NACK” is received.

  The transmission / transfer MAC PDU configuration control unit 273 divides a transmission MAC PDU configured by “delivered” MAC PDU and a transfer MAC PDU configured by “undelivered” MAC PDU, thereby configuring the RLC PDU. To change. However, the transmission MAC PDU has only a configuration (frame) and does not include actual data. This is because it is not necessary to transmit the transmission RLC SDU to the MME / UPE 11 in the downlink direction.

  The transmission / transfer MAC PDU configuration control unit 273 displays the information regarding the changed configuration as transmission MAC PDU configuration information for the “delivered” MAC PDU and as transfer MAC PDU for the “undelivered” MAC PDU. Create as configuration information. The created transfer MAC PDU configuration information is output to the transfer MAC PDU creation unit 272.

  The transmission MAC PDU configuration information includes configuration information changed for the transmission MAC PDU, information (SN, data length, etc.) associated with the transmission MAC PDU, and delivery information indicating “delivered”. The transfer MAC PDU configuration information includes changed configuration information, information accompanying the transfer MAC PDU (SN, data length, etc.), delivery information indicating “undelivered” (in addition, “untransmitted” or “retransmitted”). Medium ”information).

  For example, as shown in FIG. 37, the configuration information included in the transmission MAC PDU configuration information is information in which SN = 9 to 11 is “delivered” MAC PDU, and the configuration information included in the transfer MAC PDU is SN = 12 to 16 is information that uses “undelivered” MAC PDUs.

  The transfer MAC PDU creation unit 272 reads the “undelivered” MAC PDU stored in the HARQ temporary storage unit 271 based on the transfer MAC PDU creation information, and creates a transfer (dummy) MAC PDU. The dummy MAC PDU is, for example, a transfer MAC PDU0 type. The created transfer MAC PDU is output to the transfer RLC PDU creation unit 274.

  The transmission / transfer RLC PDU configuration control unit 275 creates transmission RLC PDU configuration information based on the transmission MAC PDU configuration information from the transmission / transfer MAC PDU configuration control unit 273, and transfers based on the transfer MAC PDU configuration information. Create RLC PDU configuration information.

  The transmission or transfer RLC PDU configuration information includes information regarding the transmission or transfer RLC PDU, information regarding the configuration of the changed RLC PDU, information associated with the transmission or transfer RLC PDU (SN, data length, etc.), transmission or transfer. MAC PDU configuration information and the like are included. For example, in the example of FIG. 37, as the transmission RLC PDU configuration information, the transmission RLC PDU with SN = 7 is information including “delivered” MAC PDUs with SN = 9 to 11.

  The transfer RLC PDU creation unit 274 creates a transfer RLC PDU from the transfer RLC PDU configuration information from the transmission / transfer RLC PDU configuration control unit 275. The transfer RLC PDU is output to the transfer RLC SDU creation unit 276.

  The transmission / transfer RLC SDU configuration control unit 277 creates transmission RLC SDU configuration information based on the transmission RLC PDU configuration information from the transmission / transfer RLC PDU configuration control unit 275, and transfers based on the transmission RLC PDU configuration information. Create RLC SDU configuration information.

  The transmission or transfer RLC SDU configuration information includes the RLC SDU configured by the transmission or transfer RLC SDU, the configuration information of the changed RLC SDU, the accompanying information (SN of the RLC SDU, the data length, etc.), the transmission Alternatively, forwarding RLC PDU configuration information is also included. As an example of the configuration information of the changed RLC SDU, for example, in the example shown in FIG. 37, information such as SN = 23 is a transmission RLC SDU for which delivery has been confirmed, SN = 24 is an undelivered transfer RLC SDU, and the like. It is.

  The transfer RLC SDU creation unit 276 creates a transfer RLC SDU based on the transfer RLC SDU configuration information from the transmission / transfer RLC SDU configuration control unit 277.

  The transmission / transfer configuration information creation unit 284 creates transmission and transfer configuration information based on the transmission and transfer RLC SDU configuration information from the transmission / transfer RLC SDU configuration control unit 277. The configuration information includes transmission or transfer RLC SDU configuration information, and further includes information about the configuration after the change. The information on the configuration after the change is, for example, in the example of FIG. 37, the transfer RLC SDU with SN = 24 is configured with one transfer RLC PDU with SN = 8, and further, five transfers with SN = 12 to 16 Information indicating that the packet is composed of MAC PDUs.

  The transmission / transfer configuration information creation unit 284 transmits the created transmission and transfer configuration information to the MME / UPE 11, the transfer destination radio base station 31, and the terminal 40. This is because the configuration of the changed RLC SDU or the like is notified in advance. When transmission configuration information or the like is transmitted to the terminal 40, it is transmitted via the encoding unit 230 or the like. Further, since the transmission configuration information includes information indicating “delivered” as the delivery information, by transmitting this to the MME / UPE 11 which is the host device, the delivery confirmation is transmitted to the host. .

  The transfer control unit 222 transfers the transfer RLC SDU from the transfer RLC SDU creation unit 276 to the transfer destination radio base station 31. Simultaneously with this transfer, transmission and transfer configuration information may be transmitted. As described above, the transmission RLC SDU only constitutes a frame, and the transfer of the RLC SDU is not performed. Further, the MAC PDU constituting the transfer RLC SDU is a transfer MAC PDU0 type.

  In the transfer destination radio base station 31, the transfer RLC SDU is received by the transfer control unit 320 and output to the RLC SDU identification unit 384.

  The transmission configuration information and the transfer configuration information are received by the transmission / transfer configuration information extraction unit 325. These pieces of information are output to the transfer RLC SDU configuration control unit 379, the transfer RLC PDU configuration control unit 378, and the transfer MAC PDU configuration control unit 377.

  The RLC SDU identification unit 384 determines whether the RLC SDU is a transfer RLC SDU based on information indicating that it is a transfer RLC SDU included in the transfer RLC SDU configuration control information extracted by the transfer RLC SDU configuration control unit 379. Identify. When it is a transfer RLC SDU, the RLC SDU identification unit 384 divides the transfer RLC SDU based on the transfer RLC SDU configuration information, creates an RLC PDU, and outputs the RLC PDU to the RLC PDU identification unit 385.

  The RLC PDU identifying unit 385 identifies whether the RLC PDU is a transfer RLC PDU based on the transfer RLC PDU configuration control information extracted from the transfer RLC PDU configuration control information 378 (particularly, information indicating that it is a transfer RLC PDU). In the case of the transfer RLC PDU, the transfer RLC PDU is divided to create a MAC PDU, which is output to the MAC PDU identification unit 386.

  The MAC PDU identification unit 386 identifies whether or not the transfer MAC PDU is a transfer MAC PDU based on the transfer MAC PDU configuration information extracted by the transfer MAC PDU configuration control unit 377, and transmits the transfer MAC PDU via the MAC PDU creation unit 387. , Temporarily store in the HARQ temporary storage unit 376. Further, when the MAC PDU identification unit 386 identifies the transfer MAC PDU, the MAC PDU identification unit 386 notifies the HARQ control unit 375 of new transmission information indicating new transmission.

  The HARQ control unit 375 requests the scheduler unit 328 to newly transmit a MAC PDU stored in the HARQ temporary storage unit 376, and the scheduler unit 328 uses one or a plurality of MAC PDUs as transmission packets to transmit packets. And the HARQ temporary storage unit 376 and the transmission packet creation unit 369 are controlled so as to be transmitted to the terminal 40 via the encoding unit 331 and the like. The created transmission packet is temporarily stored in the HARQ temporary storage unit 376.

  The transmission packet is transmitted to the terminal 40, and the error confirmation unit 430 of the terminal 40 confirms whether there is an error. Based on the result, the “ACK” or “NACK” signal created by the ACK / NACK creation unit 433 is transferred. It is transmitted to the previous radio base station 31.

  The HARQ control unit 375 of the transfer destination radio base station 31 retransmits the transmission packet in accordance with “ACK” or “NACK”.

  FIG. 68 is a diagram illustrating an example of a processing sequence according to the seventh embodiment. First, when the transfer source wireless base station 21 detects a handover (S80), it confirms whether the MAC PDU transmitted (to be transmitted) to the terminal 40 is a delivered MAC PDU or an undelivered MAC PDU (S81), and is transmitted. Then, the configuration of the transfer RLC SDU is examined (S82).

  The transfer source radio base station 21 transmits the configuration information to the MME / UPE 11, the transfer destination radio base station (Node_B2) 31, the terminal (UE1) 40, etc., and transmits the transmission MAC PDU and the transmission RLC PDU to the delivered MAC PDU. The transmission RLC SDUs are respectively configured, and the delivery confirmation is transmitted to the MME / UPE 11 (S85 to S88).

  The transfer source radio base station 21 creates a transfer MAC PDU, a transfer RLC PDU, and a transfer RLC SDU for the undelivered MAC PDU (S89 to S91).

  Thereafter, when handover is performed (S92), the transfer source radio base station 21 transfers the created transfer RLC SDU to the transfer destination radio base station 31 (S94). The transfer destination radio base station 31 confirms the MAC PDU to be transmitted (S95), and performs a new transmission to the terminal 40 (S96).

  As described above, also in the seventh embodiment, a MAC PDU including a MAC PDU for which delivery has been confirmed is not transmitted from the transfer destination radio base station 31 to the terminal 40, and only an undelivered MAC PDU is transmitted to the terminal 40. Therefore, the transmission time can be shortened and the throughput can be improved.

  Next, Example 8 will be described. Similar to the third embodiment, it is an example in which one transfer or transmission RLC SDU is created from a plurality of RLC PDUs beyond the frame (configuration) of the old RLC SDU, and is an example in the downlink direction.

  69 and 70 are diagrams illustrating examples of transfer RLC SDUs. As shown in FIG. 69, a MAC PDU being retransmitted (SN = 12) and an untransmitted MAC PDU (SN = 13 to 16) constitute an RLC PDU (SN = 8), and SN = 9. One transfer RLC SDU (SN = 22) is composed of RLC PDUs. A transfer RLC PDU is composed of two RLC PDUs. Of course, the RLC SDU may be composed of three or more RLC PDUs.

  As shown in FIG. 70, the forward RLC PDU0 type is used for undelivered MAC PDUs.

  Such transfer RLC PDUs and transfer RLC SDUs may be generated, for example, from a plurality of RLC PDUs in the transfer RLC SDU generation unit 276 (FIG. 65) in the seventh embodiment. Even if the transfer RLC SDU is configured in this way, it can be implemented in the same manner as in the eighth embodiment, and the same operational effects can be obtained.

  Next, Example 9 will be described. In the ninth embodiment, a MAC PDU “undelivered” is divided into two MAC PDUs “retransmitting” and “untransmitted” to create a transfer MAC PDU, and handover to the MAC PDU “retransmitting” is performed. This is an example in which retransmission is continued in the previous transfer destination radio base station 31.

  71 shows a configuration example of the transfer source radio base station 21 in the eighth embodiment, FIG. 72 shows a configuration example of the transfer destination radio base station 31, and FIG. 73 shows an example of a processing sequence. 46 shows a configuration example of the entire system, and FIG. 67 shows a configuration example of the terminal 40.

  The configurations of the transfer source radio base station 21 and the transfer destination radio base station 31 are substantially the same as those in the seventh embodiment. The transfer source radio base station 21 adds a point that retransmission information (information indicating a retransmission state such as the number of retransmissions, a coding rate, and a modulation method) is output from the HARQ control unit 270. In addition, also in the transfer destination radio base station 31, a point that retransmission information is extracted by the transfer MAC PDU configuration control unit 377 and notified to the HARQ control unit 375 is added.

  The part added from Example 7 is mainly demonstrated. When the transfer source radio base station 21 is transmitting a transmission packet in MAC PDU units to the terminal 40 and the handover is performed, the HARQ control unit 270 confirms the delivery state of the terminal 40. At this time, the HARQ control unit 270 receives the number of retransmissions for the old MAC PDU that has received “NACK” (the MAC PDU that is stored in the HARQ temporary storage unit 271 and cannot be configured as an RLC SDU), the coding rate, and the like. Is sent to the transmission / transfer MAC PDU configuration control unit 273.

  The HARQ control unit 270 determines that the old MAC PDU is “delivered” when “ACK” is received, and the old MAC PDU is “not transmitted” when neither “NACK” nor “ACK” is received. Unsent information is also notified to the transmission / transfer MAC PDU configuration control unit 273.

  The transmission / transfer MAC PDU configuration control unit 273 creates transfer MAC PDU configuration information and notifies the transfer MAC PDU creation unit 272 of the transfer MAC PDU configuration information. The transfer MAC PDU creation unit 272 creates a transfer MAC PDU1 type dummy MAC PDU for the “resending” MAC PDU.

  The retransmission information is notified from the transmission / transfer MAC PDU configuration control unit 273 to the transmission / transfer configuration information creation unit 284 via the transmission / transfer RLC PDU configuration control unit 275 and the transmission / transfer RLC SDU configuration control unit 277. The The retransmission information may be notified to each unit 275 or the like by including it in transfer MAC PDU configuration information or the like created by each control unit 273 or the like. In each configuration control unit 273, a configuration such as a modified transfer MAC PDU is created. From the transmission / transfer configuration information creation unit 284, as the transmission configuration information and the transfer configuration information, the MME / UPE 11, which is a higher-level device, the transfer destination wireless base The data is transmitted to the station 31 and the terminal 40 in advance or simultaneously with the transmission of the transfer RLC SDU.

  The transfer destination radio base station 31 transfers the transfer MAC PDU configuration information extracted by the transfer MAC PDU configuration control unit 377 as to whether the MAC PDU identification unit 386 is a transfer MAC PDU, and whether it is a “retransmitting” MAC PDU. Identify based on. The MAC PDU identifying unit 386 temporarily stores the MAC PDU being “retransmitted” in the HARQ temporary storage unit 376 and notifies the HARQ control unit 375 of the retransmission information extracted (or notified separately) from the transfer configuration information.

  Based on the retransmission information, the HARQ control unit 375 controls the scheduler unit 328 so as to retransmit the “under retransmission” MAC PDU stored in the HARQ temporary storage unit 376 to the terminal 40. The “resending” MAC PDU is transmitted to the terminal 40.

  Note that the MAC PDU identification unit 386 also stores “untransmitted” MAC PDUs in the HARQ temporary storage unit 376, and the HARQ control unit 375 controls to newly transmit “untransmitted” MAC PDUs to the terminal 40. To do. The subsequent steps are the same as in the seventh embodiment.

  FIG. 73 shows an example of a processing sequence. The points added from the seventh embodiment will be described. The transfer source radio base station 21 determines whether the old RLC SDU or the old MAC PDU constituting the old RLC PDU is a delivered MAC PDU or a retransmitted MAC PDU. It is confirmed whether it is a transmission MAC PDU (S100). The transfer source wireless base station 21 creates a transfer MAC PDU1 type dummy MAC PDU for the retransmitting MAC PDU (S101), and transfers MAC PDU0 type dummy MAC PDU to the untransmitted MAC PDU. Is created (S102).

  The transfer destination radio base station 31 confirms the MAC PDU to be retransmitted (S95), and retransmits the MAC PDU being retransmitted to the terminal 40 (S103).

  As described above, in the ninth embodiment, as in the seventh embodiment, the MAC PDU that has already been delivered is not transmitted to the terminal 40, so that the transmission time can be shortened and the throughput can be improved. . Further, in the ninth embodiment, “during retransmission” is distinguished from “not yet transmitted”, and “during retransmission” MAC PDUs are retransmitted from the transfer destination radio base station 31 to the terminal 40. Compared to the case of transmission, the number of retransmissions can be reduced.

  Next, Example 10 will be described. The tenth embodiment is an example of rearrangement as in the fifth embodiment, and is an example in the downlink direction.

  41 to 45 are diagrams illustrating examples of residual data in the downlink direction, configuration examples of transfer RLC SDUs, and the like.

  As shown in FIG. 41, “delivered” MAC PDUs with SN = 9, 11, 13 and “retransmitting” MAC PDUs with SN = 10 and 12 and “unsent” MAC PDUs with SN = 14 to 16 are residual data. Assuming that it is stored as

  Similarly to the fifth embodiment, “delivered” MAC PDUs are collectively configured as a transmission RLC PDU (SN = 7), and “resending” and “untransmitted” MAC PDUs are collectively combined as a transfer RLC PDU (SN = 8). ) Is configured. A transmission RLC SDU (SN = 23) is configured from the transmission RLC PDU, and a transmission RLC SDU (SN = 24) is configured from the transmission RLC PDU.

  Such rearrangement can be performed from the configuration of the seventh embodiment. That is, the transmission / transfer MAC PDU configuration control unit 273 of the transfer source wireless base station 21 (FIG. 65) collects the “delivered” MAC PDUs based on the delivery information and undelivered information from the HARQ control unit 270. Transmission MAC PDU configuration information is created so as to rearrange SNs. The transmission / transfer MAC PDU configuration control unit 273 creates transfer MAC PDU configuration information in the same manner for “undelivered”.

  Then, the transmission / transfer RLC PDU configuration control unit 275 collects the rearranged MAC PDUs into one based on the transmission and transfer MAC PDU configuration information, creates a configuration of the transmission and transfer RLC PDU, and transmits it. And transfer RLC PDU configuration information. The transfer RLC PDU creation unit 274 creates rearranged transfer RLC PDUs based on the transfer RLC PDU configuration information.

  Similarly, transmission / transfer RLC SDU configuration control unit 277 generates transmission and transfer RLC SDU configuration information, and transfer RLC SDU generation unit 276 generates transfer RLC SDU. The following is the same as in Example 7.

  FIG. 43 is an example in which a transfer RLC SDU is configured using a transfer MAC PDU0 type. 44 and 45 divide the undelivered MAC PDU into two types, “Retransmitting” and “Unsent”, and respectively configured dummy MAC PDUs of transfer MAC PDU1 type and transfer MAC PDU0 type. It is an example.

  Similar to the fifth embodiment, in the tenth embodiment, the configuration of the transmission and transfer RLC PDU and the transmission and transfer RLC SDU can be reduced, and the configuration information thereof can be reduced. Thereby, the processing time can be shortened, the transmission time can be shortened, and the throughput can be improved.

Next, Example 11 will be described. In the first embodiment, the sixth embodiment, and the like, the configuration of the RLC SDU is changed separately for the transfer RLC SDU and the transmission RLC SDU (see FIGS. 23 and 37). Accordingly, RCL
The SN of the SDU is also changed sequentially thereafter. The same applies to RLC PDUs.

  In the eleventh embodiment, a child number is used for the SN of the old RLC SDU, and the child numbers are sequentially assigned to the changed configurations. 74 and 75 are diagrams showing examples of RLC SDUs configured as described above.

  As shown in FIG. 74, the SN of the transfer RLC SDU is changed from SN = 21 to 25 to SN = 21-1 to 21-5. Thereby, it is not necessary to change the DSN of the RLC SDU after the old RLC SDU, and the change process can be reduced. In addition, the range of change can be reduced, and the memory capacity can be reduced. As shown in FIG. 75, similarly, the transfer RLC SDU can be assigned a child number to each transfer RLC SDU by taking over the SN of the old RLC SDU. The same applies to the transfer RLC PDU.

  In the upstream direction, the numbers are assigned by the transmission / transfer RLC PDU configuration control unit 254 and the transmission / transfer RLC SDU configuration control unit 258 of the transfer source radio base station 21 shown in FIG. The transmission / transfer RLC PDU configuration control unit 275 and the transmission / transfer RLC SDU configuration control unit 277 of the transfer source radio base station 21 shown in FIG. Other than that, since it is the same as the second embodiment, the seventh embodiment, etc., it can be carried out in exactly the same manner and has the same effects.

Claims (22)

The second radio base station replaces the first radio base station by handover when the radio communication is performed between the terminal and the first radio base station that performs data transfer to the host device in a predetermined transfer unit. In a wireless communication system in which wireless communication is performed between the terminal and the terminal,
In the first radio base station,
When the transmission packet transmitted from the terminal and remaining in the first radio base station is transferred to the second radio base station by the handover, the pseudo packet which is composed of the transmission packet and does not satisfy a predetermined transfer unit A packet creation unit for creating a data packet;
A wireless communication system, comprising: a transfer unit that transfers the created pseudo data packet to the second wireless base station. The second radio base station replaces the first radio base station by handover when the radio communication is performed between the terminal and the first radio base station that performs data transfer to the host device in a predetermined transfer unit. In a wireless communication system in which wireless communication is performed between the terminal and the terminal,
In the first radio base station,
When the transmission packet transmitted from the terminal and remaining in the first radio base station is transferred to the second radio base station by the handover, the pseudo packet which is composed of the transmission packet and does not satisfy a predetermined transfer unit A packet creation unit for creating a data packet;
A transfer unit that transfers the created pseudo data packet to the second radio base station;
Configuration information indicating the configuration of the pseudo data packet is created, and the created configuration information is transferred to the second radio base station and transmitted to the terminal together with the pseudo data packet or prior to transfer of the pseudo data packet. A wireless communication system comprising: a configuration information creating unit. In a wireless base station that performs wireless communication with a terminal,
When a transmission packet transmitted from the terminal and remaining in the handover source radio base station is transferred to the handover destination radio base station by handover, a pseudo data packet composed of the transmission packet and less than a predetermined transfer unit is created. A packet creation unit;
A wireless base station, comprising: a transfer unit that transfers the created pseudo data packet to the handover destination wireless base station. In a wireless base station that performs wireless communication with a terminal,
A pseudo data packet receiving unit configured to receive a transferred pseudo data packet composed of transmission packets remaining in the handover source radio base station when the handover is executed, and less than a predetermined transfer unit;
A radio base station, comprising: a packet receiving unit that requests the terminal to request transmission of the remaining packet from the received pseudo data packet and receives the packet from the terminal. When wireless communication is performed between the first wireless base station and the terminal, wireless communication is performed between the second wireless base station and the terminal instead of the first wireless base station by handover. In a wireless communication system,
In the first radio base station,
When the RLC SDU or RLC PDU composed of MAC PDUs transmitted from the terminal and remaining in the first radio base station is transferred to the second radio base station as a transfer unit by the handover,
A packet creation unit that divides or combines the RLC SDU or the RLC PDU, configures a forwarding RLC PDU or forwarding RLC SDU, creates a pseudo MAC PDU, and creates a forwarding RLC PDU or forwarding RLC SDU from the pseudo MAC PDU; ,
A wireless communication system comprising: a transfer unit configured to transfer the generated transfer RLC PDU or transfer RLC SDU to the second radio base station. In a wireless base station that performs wireless communication with a terminal,
When transferring RLC SDU or RLC PDU composed of MAC PDUs transmitted from the terminal and remaining in the radio base station by handover to the handover destination radio base station as a transfer unit,
A packet creation unit that divides or combines the RLC SDU or RLC PDU, configures a transfer RLC PDU or transfer RLC SDU, creates a pseudo MAC PDU, and creates the transfer RLC PDU or transfer RLC SDU from the pseudo MAC PDU When,
A radio base station comprising: a transfer unit configured to transfer the created transfer RLC PDU or transfer RLC SDU to the handover destination radio base station. In a wireless base station that performs wireless communication with a terminal,
The RLC SDU or RLC PDU composed of MAC PDUs transmitted from the terminal and remaining in the handover source radio base station by the handover is transferred from the handover source radio base station by the transfer RLC SDU or transfer RLC PDU obtained by dividing or combining the RLC PDUs. A transfer packet receiving unit that receives a transfer RLC SDU or a transfer RLC PDU including a pseudo MAC PDU;
A radio base station , comprising: a transmission packet receiving unit that requests the terminal to transmit a transmission request for a MAC PDU constituting the received transfer RLC SDU or the transfer RLC PDU, and receives the MAC PDU from the terminal. . When wireless communication is performed between the first wireless base station and the terminal, wireless communication is performed between the second wireless base station and the terminal instead of the first wireless base station by handover. In a wireless communication system,
In the first radio base station,
When the transmission packet to be transmitted to the terminal due to the handover and the transmission packet remaining in the first radio base station is transferred to the second radio base station, the transmission packet is configured by the transmission packet, A packet creation unit for creating a pseudo data packet less than the transfer unit;
A wireless communication system, comprising: a transfer unit that transfers the created pseudo data packet to the second wireless base station. When wireless communication is performed between the first wireless base station and the terminal, wireless communication is performed between the second wireless base station and the terminal instead of the first wireless base station by handover. In a wireless communication system,
In the first radio base station,
When the transmission packet to be transmitted to the terminal due to the handover and the transmission packet remaining in the first radio base station is transferred to the second radio base station, the transmission packet is configured by the transmission packet, A packet creation unit for creating a pseudo data packet less than the transfer unit;
A transfer unit configured to transfer the generated pseudo data packet to the second radio base station; and configuration information indicating a configuration of the pseudo data packet, and the configuration information together with the first pseudo data packet or the pseudo data packet A wireless communication system comprising: a configuration information creating unit that forwards the data packet to the second radio base station and transmits the data packet to the terminal prior to the data packet transfer. In a wireless base station that performs wireless communication with a terminal,
When a handover packet is transmitted, a transmission packet remaining in the radio base station is transferred to the handover destination radio base station.
A packet creation unit configured to create a pseudo data packet composed of the transmission packet transmitted to the terminal and less than a predetermined transfer unit;
A wireless base station, comprising: a transfer unit that transfers the created pseudo data packet to the handover destination wireless base station. In a wireless base station that performs wireless communication with a terminal,
A dummy packet receiving unit configured to receive a transferred pseudo data packet composed of transmission packets remaining in a handover source radio base station when a handover is executed, and less than a predetermined transfer unit;
A radio base station, comprising: a packet transmission unit configured to transmit a transmission packet corresponding to the pseudo data packet from the received pseudo data packet to the terminal. When wireless communication is performed between the first wireless base station and the terminal, wireless communication is performed between the second wireless base station and the terminal instead of the first wireless base station by handover. In a wireless communication system,
In the first radio base station,
When transferring RLC SDUs or RLC PDUs composed of MAC PDUs remaining in the first radio base station due to the handover to the second radio base station as a transfer unit,
A packet creation unit that divides or combines the RLC SDU or the RLC PDU, configures a forwarding RLC PDU or forwarding RLC SDU, creates a pseudo MAC PDU, and creates a forwarding RLC PDU or forwarding RLC SDU from the pseudo MAC PDU; ,
A wireless communication system comprising: a transfer unit configured to transfer the generated transfer RLC PDU or transfer RLC SDU to the second radio base station. In a wireless base station that performs wireless communication with a terminal,
When handover is performed, when RLC SDU or RLC PDU composed of MAC PDUs remaining in the handover source radio base station is transferred to the handover destination radio base station as a transfer unit,
A packet creation unit that divides or combines the RLC SDU or the RLC PDU, configures a forwarding RLC PDU or forwarding RLC SDU, creates a pseudo MAC PDU, and creates a forwarding RLC PDU or forwarding RLC SDU from the pseudo MAC PDU; ,
A radio base station, comprising: a transfer unit configured to transfer the created transfer RLC PDU or transfer RLC SDU to the handover destination radio base station. In a wireless base station that performs wireless communication with a terminal,
When a handover is executed, an RLC SDU or RLC PDU composed of MAC PDUs remaining in the handover source radio base station is divided or combined, and a pseudo MAC PDU transferred from the handover source radio base station is displayed. A transfer packet receiving unit for receiving a transfer RLC SDU or a transfer RLC PDU including:
A radio base station, comprising: a transmission packet transmission unit configured to transmit the received transfer RLC PDU or MAC PDU constituting the transfer RLC SDU to the terminal. The second radio base station replaces the first radio base station by handover when the radio communication is performed between the terminal and the first radio base station that performs data transfer to the host device in a predetermined transfer unit. In a wireless communication method in a wireless communication system in which wireless communication is performed between the terminal and the terminal,
In the first radio base station,
When transferring a transmission packet transmitted from a terminal and remaining in the first radio base station by the handover, to the second radio base station,
Create a pseudo data packet composed of the transmission packet and less than a predetermined transfer unit,
A wireless communication method comprising transferring the created pseudo data packet to the second wireless base station. When wireless communication is performed between the first wireless base station and the terminal, wireless communication is performed between the second wireless base station and the terminal instead of the first wireless base station by handover. In a wireless communication method in a wireless communication system,
In the first radio base station,
When the transmission packet remaining in the first radio base station is transferred to the second radio base station by the handover,
Create a pseudo data packet composed of the transmission packet and less than a predetermined transfer unit,
A wireless communication method comprising transferring the created pseudo data packet to the second wireless base station. In the second radio base station,
A pseudo data packet receiver for receiving the pseudo data packet;
The wireless communication system according to claim 1, further comprising: a transmission packet receiving unit that requests the terminal to transmit a transmission request for the transmission packet from the received pseudo data packet and receives the transmission packet from the terminal. In the second radio base station,
A transfer packet receiver that receives the transfer RLC PDU or the transfer RLC SDU;
The transmission packet receiving unit that requests the terminal to transmit a transmission request for the received transfer RLC PDU or the MAC PDU constituting the transfer RLC SDU, and receives the MAC PDU from the terminal. The wireless communication system described. In the second radio base station,
A dummy packet receiver for receiving the pseudo data packet;
The wireless communication system according to claim 8, further comprising: a packet transmission unit configured to transmit a transmission packet corresponding to the pseudo data packet from the received pseudo data packet to the terminal. In the second radio base station,
A transfer packet receiver that receives the transfer RLC PDU or the transfer RLC SDU;
The wireless communication system according to claim 12, further comprising: a transmission packet transmission unit configured to transmit the received transfer RLC PDU or MAC PDU configuring the transfer RLC SDU to the terminal. In the second radio base station,
Receiving the pseudo data packet;
The wireless communication method according to claim 15, wherein the terminal requests a transmission request for the transmission packet from the received pseudo data packet, and receives the transmission packet from the terminal. In the second radio base station,
Receiving the pseudo data packet;
The wireless communication method according to claim 16, wherein a transmission packet corresponding to the pseudo data packet is transmitted to the terminal from the received pseudo data packet.

Images