CN101132609A

Movatterモバイル変換

Info

Publication number: CN101132609A
Application number: CNA2006101099128A
Authority: CN
Inventors: 邵飞; 郑潇潇
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2006-08-22
Filing date: 2006-08-22
Publication date: 2008-02-27
Anticipated expiration: 2026-08-22
Also published as: CN101132609B; WO2008025253A1

Abstract

Translated fromChinese

本发明公开了一种切换过程中转发数据的方法及系统，用以解决目前切换过程中，下行数据转发会带来比较大的时延的问题。本发明方法包括：切换时，由源eNodeB按序将业务数据单元SDU转发到目标eNodeB，并告知转发数据的结束点；目标eNodeB按照接收顺序将收到的SDU向用户侧转发，并告知转发数据的结束点；用户侧RLC将收到的SDU递交到用户侧PDCP层，并告知转发数据的结束点；PDCP层以PDCP编号对转发数据结束点之前的SDU进行排序并向高层递交。本发明可以减少下行数据转发带来的时延。

The invention discloses a method and system for forwarding data in the handover process, which is used to solve the problem of relatively large time delay caused by downlink data forwarding in the current handover process. The method of the present invention includes: when switching, the source eNodeB forwards the service data unit SDUs to the target eNodeB in sequence, and informs the end point of the forwarded data; the target eNodeB forwards the received SDUs to the user side according to the receiving order, and informs the forwarded data The end point of the forwarded data; the RLC on the user side submits the received SDU to the PDCP layer on the user side, and informs the end point of the forwarded data; the PDCP layer sorts the SDUs before the end point of the forwarded data by the PDCP number and submits it to the upper layer. The present invention can reduce the delay caused by downlink data forwarding.

Description

Transmit the method and system of data in a kind of handoff procedure

Technical field

The present invention relates to the communications field, particularly relate to the method and system of transmitting data in a kind of handoff procedure.

Background technology

Begun the research work of WCDMA in early 1990s, since 98 years till now, the technical specification of the WCDMA system Release 99 that passed by, Release 4, Release 5, Release 6 these several stages, and the standardization effort about Release 7 comes into effect at present.Meanwhile, the research of more long-term LTE (Long Term Evolution) has also begun to become gradually the new focus of standardization effort.

In Release 99 systems, downlink transfer adopts dedicated channel, and its maximum rate can reach 384kbps.From Release 4, MSC (Mobile Service Switch Center) is split into MSC Server and MGW (Multi-media GateWay), thereby will controls and service detach.In Release 5, introduced the notion of IMS (IP Multi-media Subsystem), its IP-based transport layer, and on wireless access technology, introduced HSDPA (High Speed Downlink Packet Access), make downstream rate can reach 14.4Mbps.In Release 6, introduce HSUPA (High SpeedUplink Packet Access) technology, made upstream rate can reach 5.76Mbps.Above-mentioned several standard is more stable, at present Release 7 protocol targets of discussing be on the basis of Release 6 by little change, improve systematic function.LTE will be brand-new from the system framework to the physical layer, be intended to for the user provides higher speed the more performance service.UTRAN among the LTE is called as E-UTRAN at present.

Referring to shown in Figure 1, be the E-UTRAN system architecture diagram, it comprises an IAD aGW (accessgateway), and a plurality of base station eNodeB that communicate with.

Described aGW is in core net; can comprise a plurality of aGW in the core net; the initiation of aGW duty pager, the condition managing of LTE_IDLE, customer side encryption, functions such as the safety of PDCP PDCP (PacketData Convergence Protocol), System Architecture Evolution SAE (System Architecture Evolution) carrying control, Non-Access Stratum NAS (Non Access stratum) signaling and integrity protection.

Described eNodeB is positioned at Access Network, links to each other the scheduling of duty pager information and transmission, the scheduling of broadcast message and transmission, the distribution of up-downgoing resource, radio bearer control, radio management control, the connection mobility control under the LTE_ACTIVE state with aGW.

At present, E-UTRAN protocol stack architecture figure is referring to shown in Figure 2.

Prior art one: based on above-mentioned E-UTRAN protocol stack architecture, the data forwarding flow process when switching in the E-UTRAN system is referring to shown in Figure 3.After source eNodeB received that switching preparation confirms, beginning was transmitted data to target eNode B, and described data are the Service Data Unit SDU of rlc layer, i.e. the protocol Data Unit PDU of PDCP layer.Between transfer period, rlc layer is reseted, and data of sending to target eNode B from aGW and source eNodeB transmit the data of coming and can be stored in the target eNode B, by the time target eNode B and user terminal synchronously on, and after setting up communication, begin to send data to user terminal.Because when switching, rlc layer is reseted, the data that the data that source eNodeB transmits to target eNode B may send to target eNode B with aGW staggeredly arrive target eNode B, may be out of order so the source eNodeB that target eNode B is received transmits the data of coming.

The rlc layer of target eNode B is to obtain RLCPDU after described out of order data renumber by reception in proper order, remains out of order but obtain RLC PDU after obviously renumbeing.Obtain RLC PDU after target eNode B will renumber again and be transmitted to user terminal, be delivered to the PDCP layer by user terminal again, obviously can't guarantee professional continuity.

Prior art two: LTE strides the switching flow of different e NodeB at present, referring to shown in Figure 4, comprises the following steps:

1, the principle of UE triggering status report is issued or the like by agreement formulation or system message.

2, source eNodeB makes the switching decision according to measurement report and RRM information that UE reports.Switch preparation for target eNode B is done, source eNodeB can send to target eNode B with relevant information in handoff request message.

3, the target eNode B switching of doing layer one deck two is prepared, and to the new C-RNTI of source eNodeB feedback and possible other parameters such as access parameter, SIB or the like is as response.After receiving the affirmation that HO prepares, source eNodeB begins to transmit packet to target eNode B.

4, UE can receive and contain new C-RNTI and possible time started, the HANDOVER COMMAND message of necessary parameter such as target e NB SIB.This rrc message is used RLC AM mode transfer, that is to say that UE RLC can confirm to guarantee its reliability this information.

5, the time started in HO COMMAND overtime, the synchronizing process that UE will carry out with target eNode B begins its uplink synchronous.

6, network carries out ascending resource distribution and timing advance.These resources send switching affirmation " HANDOVER CONFIRM " message for UE and use to target eNode B, and the handoff procedure of UE finishes simultaneously." HO CONFIRM " message that UE sends is with the transmission of RLC affirmation mode, needs the affirmation of network side to guarantee its reliability.

7a, target eNode B notification source eNodeB successful switch, source eNodeB will delete the data of having transmitted in the buffer memory like this.If also have data or UPE still to continue to send data to source eNodeB in the eNodeB buffer memory of source, source eNodeB can continue to transmit these data to target eNode B.

7b, can directly transmit packet to correct target eNode B in order to make UPE, the UE positional information changes and can upgrade at Mobility Management Entity/data surface entity MME/UPE.

When LTE strode different e NodeB switching, first kind of processing scheme to user data was as follows:

1) issues after switching command gives UE (HO COMMAND) as source eNodeB, not begun all SDU (according to numbering) from first and be forwarded to target eNode B in the RLC buffer memory among the eNodeB of source by correct (i.e. minimum PDU or the SDU of numbering) that confirms of UE.

2) target eNode B is rebuild corresponding RLC entity, and buffer memory is transmitted the packet of coming, when receiving the laggard line data face transmission of the synchronous information of UE.Do not need mutual RLC control context (as information such as SN) like this between source eNodeB and the target eNode B, target eNode B sends to user side after the data of transmitting are renumberd or read the high-rise numbering of each packet.

3) aGW is after carrying out transmission path change (path switch), and the high level data bag will be issued to target eNode B from aGW.At this moment the problem that can occur, promptly first new data packets that issues from aGW (after path switching) arrives the time of target eNode B, and it is Zao to arrive time of target eNode B than last packet of being transmitted by source eNodeB.In the target eNode B side situation that data packet disorder arrives will appear like this.In order to address this problem, can be in eNodeB, according to high level numbering (PDCP numbering) necessarily reorder (can not doing) yet.

The problem of this scheme is to transmit from first and is not meaned that by the correct packet of confirming of UE some data discontinuous but that correctly received by UE can be transmitted again, and this has just wasted interface-free resources, has also increased handover delay (from high-level perspective).Simultaneously, this lot of data forwarding can cause the more late arrival target eNode B of sending from the aGW high level of data, if if this out of order reordering in target eNode B can be brought bigger time delay.

When LTE strode different e NodeB switching, second kind of processing scheme to user data was as follows:

1) issues after switching command gives UE (HO COMMAND) as source eNodeB, (these SDU can not be discontinuous, optionally) are forwarded to target eNode B by the correct SDU that confirms of UE in the RLC buffer memory among the eNodeB of source.

2) target eNode B is rebuild corresponding RLC entity, and the packet that buffer memory is transmitted when receiving the laggard line data face transmission of the synchronous information of UE, sends after renumbeing or read the high-rise numbering of each bag for the packet of these forwardings.

3) out of order problem is equally also arranged here.Be that aGW is after carrying out transmission path change (path switch), the high level data bag will be issued to target eNode B from aGW, at this moment first packet that issues from aGW (after path switching) can occur than the early situation of transmitting by source eNodeB that arrives target eNode B of last packet, cause target eNode B the out of order reception of packet to occur.

Thisly carry out scheme that selectivity retransmits and compare first kind of processing scheme and optimize to some extent, can not waste interface-free resources user data.Out of order problem takes place still can't solving but transmit data after the conversion of data and transmission path, and reorders in target eNode B and can bring bigger time delay.

Summary of the invention

The invention provides the method and system of transmitting data in a kind of handoff procedure, in order to solve in the present handoff procedure, the downlink data forwarding can bring the problem of bigger time delay.

The inventive method comprises the following steps:

When A, switching, according to the order of sequence Service Data Unit SDU is forwarded to target eNode B, and informs the end point of transmitting data by source eNodeB;

B, target eNode B are transmitted the SDU that receives according to the reception order to user side, and inform the end point of transmitting data;

C, user side RLC are delivered to user side PDCP layer with the SDU that receives, and inform the end point of transmitting data;

D, PDCP layer sort to the SDU before the forwarding ED point with the PDCP numbering and submit to high level.

Wherein, the SDU that source eNodeB transmits according to the order of sequence in the steps A perhaps is not by the correct SDU that confirms of user from first for not by the correct SDU that confirms of user.

Wherein, inform described in the steps A that the mode of transmitting ED point is: for identify last SDU of forwarding by transmission network; Perhaps, in the target eNode B side timer is set, if do not receive a SDU in timing, then target eNode B judges that in view of the above transmitting the data node arrives.

Wherein, among the step B, target eNode B is divided into protocol Data Unit PDU with the SDU that receives, and according to transfer sequence each PDU is carried out the RLC numbering; Inform described in the step B that the mode of transmitting ED point is: in the packet header of last PDU of last SDU that need transmit of transmission, add indication bit; Perhaps, by showing that signaling method identifies last PDU of last SDU that need transmit.

Further, among the step C, described user side RLC detects and has complete SDU in the local cache, then submits to the PDCP layer immediately.

Further again, among the step C, when user side RLC will number when being delivered to the PDCP layer by the SDU of the numbering correspondence of the PDU that identified or finishing the RLC ordering, the out of order reception of notice PDCP layer finishes, and well is submitted the follow-up SDU that receives according to the order of sequence.

Further, among the step B, target eNode B is added indication bit in the packet header of last PDU of each SDU that transmits, or by showing last PDU of each SDU that the signaling method sign is transmitted.

Further again, among the step C, when the SDU of the PDU correspondence that user side RLC will be identified was delivered to the PDCP layer or finishes the RLC ordering, the out of order reception of notice PDCP layer finished, and submits the follow-up SDU that receives according to the order of sequence.

Further, among the step C, the PDU that described user side RLC buffer memory target eNode B is sent, and according to the PDU number sorting, after correctly receiving the PDU that is identified as user side RLC, PDU to buffer memory carries out the SDU verification, and the SDU that will number the numbering correspondence of the PDU that is identified smaller or equal to quilt afterwards submits to the PDCP layer in the lump.

Further again, among the step C, the SDU of user side RLC after with verification is submitted to after the PDCP layer, and notice PDCP layer is transmitted ED, and submits the follow-up SDU that receives according to the order of sequence.

Wherein, among the step B, target eNode B is divided into PDU with the SDU that receives, and according to transfer sequence each PDU is carried out the RLC numbering; Inform described in the step B that the mode of transmitting ED point is: after sending each PDU of last SDU that need transmit, the packet header of last PDU that transmits first SDU that comes from aGW, add indication bit; Perhaps, by showing signaling method sign last PDU from first next SDU of aGW transmission.

Further again, among the step C, the SDU that user side RLC will number the numbering correspondence of the PDU that is identified less than quilt is delivered to the PDCP layer or finishes RLC when sorting, and the out of order reception of notice PDCP layer finishes, and submits the follow-up SDU that receives according to the order of sequence.

Further, among the step B, target eNode B is after sending each PDU of last SDU that need transmit, the packet header of last PDU that transmits each SDU that comes from aGW, add indication bit, perhaps by showing signaling method sign last PDU from each next SDU of aGW transmission.

Further again, after target eNode B is received the response message that PDU that an arbitrary quilt identifies correctly received, stop to add the operation of indication.

Further, among the step C, the PDU that described user side RLC buffer memory target eNode B is sent, and according to the PDU number sorting, after receiving the PDU that is identified as user side RLC, the PDU that numbers the numbering of the PDU that is identified less than quilt in the buffer memory is carried out the SDU verification, and the SDU that will number the numbering correspondence of the PDU that is identified less than quilt afterwards submits to the PDCP layer in the lump.

Further again, the SDU of user side RLC after with verification is submitted to after the PDCP layer, and notice PDCP layer is transmitted ED, and submits the follow-up SDU that receives according to the order of sequence.

In sum, whether the PDCP numbering of the PDU that described PDCP layer record received and the mapping relations of RLC numbering are out of order SDU according to these mapping relations and the verification of forwarding ED point at the SDU that transmits the PDU correspondence of receiving before the ED point.

In sum, numbering complete and that submitted the PDU of PDCP layer received in described user side RLC record, according to the numbering of the PDU of described record and the SDU that transmits the PDU correspondence that ED point verification received before forwarding ED point whether be out of order SDU.

System of the present invention comprises:

Submit the unit, it is positioned at the user side rlc layer, is used for submitting SDU to the PDCP layer;

Sequencing unit, it is positioned at the PDCP layer, is used for sorting to submitting the SDU that sends the unit before the forwarding ED point with the PDCP numbering;

Transmit ED point notification unit, it is arranged in source eNodeB, target eNode B and user side RLC, is used for notice and transmits the ED point.

Further, described system also comprises:

First trigger element, it is positioned at the user side rlc layer, when being used for receiving first SDU that target eNode B sends after switching beginning, triggers the described unit of submitting;

Second trigger element, it is positioned at the PDCP layer, is used for triggering sequencing unit and beginning ordering when user side carries out the RLC replacement.

Beneficial effect of the present invention is as follows:

The inventive method is not carried out out of order reordering at rlc layer, but when switching, by source eNodeB successively by target eNode B and user side RLC, to be delivered to the PDCP layer of user side, and inform the end point of transmitting data successively by the correct SDU that confirms of user by the correct SDU that confirms of user or from first; The PDCP layer sorts to the SDU before the end point of transmitting data with the PDCP numbering and submits to high level.

In order to support the inventive method, the present invention also provides the system that transmits data in a kind of handoff procedure.

In sum, the present invention reorders at the PDCP of user side layer and can be supported in target eNode B and do not need to reorder, and transmits the time delay of bringing thereby reduce downlink data.

Reorder at the PDCP of user side layer, the reliability of submitting scheme in proper order with respect to existing user side RLC has had stricter assurance, reduces the complexity of more high-rise processing.

When the PDCP layer of user side sorted, user side RLC can not carry out the RLC number sorting of PDU, promptly can support out of order submitting, thereby has reduced the processing delay that the unnecessary two-layer ordering of user side brings.

Description of drawings

Fig. 1 is the E-UTRAN system architecture diagram;

Fig. 2 is E-UTRAN protocol stack architecture figure;

Fig. 3 is the data forwarding flow chart when switching in the E-UTRAN system;

Fig. 4 strides the switching flow figure of different e NodeB for present LTE;

Fig. 5 is the inventive method flow chart of steps;

Fig. 6 is a system configuration schematic diagram of the present invention.

Embodiment

For in handoff procedure, reduce downlink data and transmit the time delay of bringing, the invention provides the method for transmitting data in a kind of handoff procedure, referring to shown in Figure 5, comprise following key step:

When S1, switching, eNodeB is forwarded to target eNode B with SDU according to the order of sequence by the source, and informs the end point of transmitting data.

During switching, source eNodeB will be transmitted to target eNode B by the correct SDU that confirms of user according to reception order (promptly transmitting according to the order of sequence) by the correct SDU that confirms of user or from first, and inform the end point of transmitting data.

Source eNodeB is transmitting to target eNode B in the process of SDU, identifies last SDU (last SDU that is forwarding adds label, indicating the end point of out of order reception, and by the FP transmission) of forwarding by transmission network; Perhaps, in the target eNode B side timer is set, if do not receive a SDU in timing, then target eNode B judges that in view of the above transmitting the data node arrives.

S2, target eNode B are transmitted the SDU that receives according to the reception order to user side, and inform the end point of transmitting data.

In this step, target eNode B is divided into PDU with the SDU that receives, and according to transfer sequence each PDU is carried out the RLC numbering; Based on the PDU of cutting apart, target eNode B informs that it is one of following manner that user side is transmitted the mode of ED point:

Mode 11: target eNode B is added indication bit in the packet header of last PDU of last SDU that need transmit that sends; Perhaps, by showing that signaling method identifies last PDU of last SDU that need transmit.

Mode 12:(is as the mode of texturing of mode one) target eNode B adds indication bit in the packet header of last PDU of each SDU that transmits; Perhaps, by showing last PDU of each SDU that the signaling method sign is transmitted.Promptly not only last PDU of last SDU that need transmit is identified, and last PDU of each SDU before it is identified.

Mode 13: target eNode B is added indication bit the packet header of last PDU that transmits first SDU that comes from aGW after sending each PDU of last SDU that need transmit; Perhaps, by showing signaling method sign last PDU from first next SDU of aGW transmission.

Mode 14:(is as the mode of texturing of mode three) target eNode B after sending each PDU of last SDU that need transmit, the packet header of last PDU of each SDU that comes from aGW transmission, add indication bit; Perhaps, by showing signaling method sign last PDU from each next SDU of aGW transmission.After target eNode B is received the response message that PDU that an arbitrary quilt identifies correctly received, stop to add the operation of indication.

S3, user side RLC are delivered to user side PDCP layer with the SDU that receives, and inform the end point of transmitting data.

User side RLC is to the out of order function of submitting of PDCP layer, triggers when receiving first SDU that target eNode B sends after switching beginning.

In this step, user side is one of following manner with the mode that SDU is delivered to the PDCP layer:

Mode 21 (corresponded manner 11 is to mode 14): user side RLC detects and has complete SDU in the local cache, then submits (out of order submitting) to the PDCP layer immediately.

Mode 22 (corresponded manner 11): the PDU that user side RLC buffer memory target eNode B is sent, and according to the PDU number sorting, after correctly receiving the PDU that is identified as user side RLC, PDU to buffer memory carries out the SDU verification, and the SDU that will number the numbering correspondence of the PDU that is identified smaller or equal to quilt afterwards submits to the PDCP layer in the lump.

Mode 23 (corresponded manner 12): the PDU that user side RLC buffer memory target eNode B is sent, and according to the PDU number sorting, after receiving the PDU that is not identified as user side RLC, numbering in the buffer memory is carried out the SDU verification less than the PDU of the numbering of the PDU that is not identified, and the SDU that will number afterwards less than the numbering correspondence of the PDU that is not identified submits to the PDCP layer in the lump.

Mode 24 (corresponded manner 13 and mode 14):

The PDU that user side RLC buffer memory target eNode B is sent, and according to the PDU number sorting, after receiving the PDU that is identified as user side RLC, the PDU that numbers the numbering of the PDU that is identified less than quilt in the buffer memory is carried out the SDU verification, and the SDU that will number the numbering correspondence of the PDU that is identified less than quilt afterwards submits to the PDCP layer in the lump.

In this step, user side informs that it is one of following manner that the PDCP layer is transmitted the mode of the end point of data:

Mode 31 (corresponding aforesaid way 21+ mode 11): when user side RLC will number when being delivered to the PDCP layer by the SDU of the numbering correspondence of the PDU that identified or finishing the RLC ordering, the out of order reception of notice PDCP layer finishes, and submits the follow-up SDU that receives according to the order of sequence.

Mode 32 (corresponding aforesaid way 21+ mode 12): when the SDU of the PDU correspondence that user side RLC will be identified was delivered to the PDCP layer or finishes the RLC ordering, the out of order reception of notice PDCP layer finished, and submits the follow-up SDU that receives according to the order of sequence.

The corresponding aforesaid way 21+ of mode 33:(mode 13; Mode 21+ mode 14): the SDU that user side RLC will number the numbering correspondence of the PDU that is identified less than quilt is delivered to the PDCP layer or finishes RLC when sorting, and the out of order reception of notice PDCP layer finishes, and submits the follow-up SDU that receives according to the order of sequence.

Mode 34 (corresponding aforesaid way 22, mode 23 and mode 24): the SDU of user side RLC after with verification is submitted to after the PDCP layer, and notice PDCP layer is transmitted ED, and submits the follow-up SDU that receives according to the order of sequence.

Further, SDU is delivered to the mode of PDCP layer based on above-mentioned user side, and corresponding with it forwarding ED point, user side RLC also can write down and receive numbering complete and that submitted the PDU of PDCP layer, according to the numbering of the PDU of described record and the SDU that transmits the PDU correspondence that ED point verification received before forwarding ED point whether be out of order SDU, thereby avoid the SUD of subsequent order to arrive user side prior to last out of order SDU, cause order SUD to be mistaken as out of order SDU, and then be committed to the problem (also can in step S4, carry out) that the PDCP layer misprints preface.

S4, PDCP layer sort to the SDU before the forwarding ED point with the PDCP numbering and submit to high level.

The PDCP layer carries out triggering when RLC resets ranking function at user side, the PDCP layer extracts the PDCP numbering of each PDU that receives, and with the PDCP numbering SDU is reordered, when receiving the forwarding ED notice that user side is sent, finish ordering, and the SDU after will sorting submits to more high-rise.Afterwards by the reception order to the more high-rise SDU that submits.

Whether further, the PDCP layer also can write down the PDCP numbering of the PDU that receives and the mapping relations of RLC numbering, be out of order SDU according to these mapping relations and the verification of forwarding ED point at the SDU that transmits the PDU correspondence of receiving before the ED point.

Below specifically describe the inventive method by eight examples.

Method example one: the combination of aforesaid way 11, mode 21 and mode 31.

L11, receive that the switching affirmation of target eNode B or source eNodeB are after user side sends switching command as source eNodeB, source eNodeB will not transmitted to target eNode B by the correct SDU that confirms of user by the correct SDU that confirms of user side or from first according to its reception order.Identify last SDU of forwarding simultaneously by transmission network; Perhaps, in the target eNode B side timer is set, if do not receive a SDU in timing, then target eNode B judges that in view of the above transmitting the data node arrives.

L12, target eNode B generate corresponding RLC entity, the SDU that receives with buffer memory.After switching affirmation of receiving user side or synchronizing information, the transmission of beginning user face data.In the process of transmitting SDU, the priority that target eNode B arrives according to the SDU packet, order (is about to SDU and is divided into several PDU the RLC numbering that the SDU that receives carries out PDU again, and order is to described PDU numbering), perhaps read PDCP numbering among the SDU, send to user side according to the reception order again.

In this step, the SDU that receives is not sorted with the PDCP numbering in the target eNode B side.

L13, target eNode B are in the process of the out of order transmission of user side SDU, in the packet header of last PDU of last SDU that need transmit that sends, add indication bit, perhaps, transmit the ED point to inform user side by showing that signaling method identifies last PDU of last SDU that need transmit.

L14, after user side is received switching command message (can on meet step L11), the operation of the RLC entity that begins to reset, comprising: notice high-rise (PDCP layer) generates (activation) PDCP sequencing unit, begins out of order ordering; Detect RLC and receive in the buffer memory whether have complete SDU; Delete incomplete SDU segmentation; Parameters such as initialization user side timer and state variable.

L15, for the user side RLC entity after resetting, when receiving first SDU that target eNode B sends, trigger RLC and receive the out of order function of submitting of buffer memory reorganization, as long as detect complete SDU, then submit to the PDCP layer immediately, no matter the priority of PDU numbering.User side begins the SDU that will receive from target eNode B in the out of order mode of submitting, and submits to the PDCP layer.

L16, when user side RLC will number when being delivered to the PDCP layer by the SDU of the numbering correspondence of the PDU that identified or finishing the RLC ordering, the out of order reception of notice PDCP layer finishes, and submits the follow-up SDU that receives according to the order of sequence; Behind the PDU that promptly correct reception is identified, user side is submitted greater than the SDU implementation of the PDU numbering N correspondence that is identified according to the order of sequence to PDU numbering in the RLC reception buffer memory, and must wait until that PDU numbering is successfully received smaller or equal to the PDU of N or deleted after, just can recombinate greater than the complete S DU of the PDU correspondence of N and to deliver to the PDCP layer.Described PDU is deleted to be according to the setting mechanism that reorders, by window or timer control.

L17, PDCP layer reorder according to the PDCP numbering of the SDU that receives.

L18, when PDU numbering all is committed to the PDCP layer smaller or equal to each PDU of N or reaches maximum retransmission or shift out receive window, user side RLC entity notice PDCP entity, the SDU after PDCP will sort delivers to more high-rise, hangs up its ranking function.

Method example two: the combination of aforesaid way 12, mode 21 and mode 32.

L21 is identical with L11 and L12 with L22.

L23, target eNode B are sending in the process of SDU to user side, add indication bit in the packet header of last PDU of each SDU that transmits; Perhaps, by showing last PDU of each SDU that the signaling method sign is transmitted.

L24 is identical with L14.

L25 is identical with L15.

When the SDU of the PDU correspondence that L26, user side RLC will be identified was delivered to the PDCP layer or finishes the RLC ordering, the out of order reception of notice PDCP layer finished, and submits the follow-up SDU that receives according to the order of sequence; Behind the PDU that promptly correct reception is not identified, user side is submitted more than or equal to the SDU implementation of the PDU numbering N correspondence that is not identified according to the order of sequence to PDU numbering in the RLC reception buffer memory, and must wait until that PDU numbering is successfully received less than the PDU of N or deleted after, just can recombinate more than or equal to the complete S DU of the PDU correspondence of N and to deliver to the PDCP layer.Described PDU is deleted to be according to the setting mechanism that reorders, by window or timer control.

L27 is identical with L17.

L28, when PDU numbering all is committed to the PDCP layer less than each PDU of N or reaches maximum retransmission or shift out receive window, user side RLC entity notice PDCP entity, the SDU after PDCP will sort delivers to more high-rise, hangs up its ranking function.

Method example three: the combination of aforesaid way 11, mode 22 and mode 34.

L31 to L34 is identical with L11 to L14.

The PDU that L35, user side RLC buffer memory target eNode B are sent, and according to the PDU number sorting, after correctly receiving the PDU that is identified as user side RLC, PDU to buffer memory carries out SDU verification (promptly numbering being carried out the SDU detection smaller or equal to all PDU that the PDU that is identified numbers N), and the SDU that will number the numbering correspondence of the PDU that is identified smaller or equal to quilt afterwards submits to the PDCP layer in the lump.SDU greater than the PDU correspondence of N submits according to the order of sequence to numbering.

L36, the user side RLC SDU after with verification is submitted to after the PDCP layer, and notice PDCP layer is transmitted ED, and submits the follow-up SDU that receives according to the order of sequence.

L37, PDCP layer reorder according to the PDCP numbering of the SDU that receives.

L38 is identical with L18.

Method example four: the combination of aforesaid way 13, mode 21 and mode 33.

L41 is identical with L11 and L12 with L42.

L43, target eNode B are sending in the process of SDU to user side, after sending each PDU of last SDU that need transmit, the packet header of last PDU that transmits first SDU that comes from aGW, add indication bit, perhaps, transmit the end point of data to inform user side by showing signaling method sign last PDU from first next SDU of aGW transmission.

L44 is identical with L14 and L15 with L45.

The SDU that L46, user side RLC will number the numbering correspondence of the PDU that is identified less than quilt is delivered to the PDCP layer or finishes RLC when sorting, and the out of order reception of notice PDCP layer finishes, and submits the follow-up SDU that receives according to the order of sequence.

L47, PDCP layer reorder according to the PDCP numbering of the SDU that receives.

After L48, PDCP layer are received the notice of user side RLC entity, deliver to the SDU after the ordering more high-rise, hang up its ranking function.

Method example five: the combination of aforesaid way 14, mode 21 and mode 33.

L51 is identical with L11 and L12 with L52.

L53, target eNode B after sending each PDU of last SDU that need transmit, are added indication bit sending in the process of SDU to user side the packet header of last PDU that transmits each SDU that comes from aGW; Perhaps, by showing signaling method sign last PDU from each next SDU of aGW transmission.After target eNode B is received the response message that PDU that an arbitrary quilt identifies correctly received, stop to add the operation of indication.

L54 is identical with L14 and L15 with L55.

The SDU that L56, user side RLC will number the numbering correspondence of the PDU that is identified less than quilt is delivered to the PDCP layer or finishes RLC when sorting, and the out of order reception of notice PDCP layer finishes, and submits the follow-up SDU that receives according to the order of sequence; And after receiving the PDU that is identified, return the response message of correct reception to target eNode B.

L57 is identical with L47 and L48 with L58.

Method example six: the combination of aforesaid way 13, mode 24 and mode 34.

L61 to L63 is identical with L41 to L43.

The PDU that L64, user side RLC buffer memory target eNode B are sent, and according to the PDU number sorting, after receiving the PDU that is identified as user side RLC, the PDU that numbers the numbering of the PDU that is identified less than quilt in the buffer memory is carried out the SDU verification, and the SDU that will number the numbering correspondence of the PDU that is identified less than quilt afterwards submits to the PDCP layer in the lump.

L65, the user side RLC SDU after with verification is submitted to after the PDCP layer, and notice PDCP layer is transmitted ED, and submits the follow-up SDU that receives according to the order of sequence.

L67 is identical with L37 and L38 with L68.

Method example seven: the combination of aforesaid way 11, mode 21 and mode 31; And PDCP layer record and according to the out of order SDU of mapping relations verification.

L71 to L74 is identical with L11 to L14.

L75 is identical with L15; And the PDCP numbering of the PDU that PDCP layer record received and the mapping relations of RLC numbering.

L76 is identical with L16.

Whether L77, PDCP layer are out of order SDU according to these mapping relations and the verification of forwarding ED point at the SDU that transmits the PDU correspondence of receiving before the ED point earlier.Afterwards, the PDCP layer reorders according to the PDCP numbering of the PDU that receives again.

L78 is identical with L18.

Method example eight: the combination of aforesaid way 11, mode 21 and mode 31; And the RLC numbering of PDU complete and that submitted the PDCP layer received in user side RLC record, and the out of order SDU of verification.

L81 to L874 is identical with L11 to L14.

L85 is identical with L15; And the RLC numbering of PDU complete and that submitted the PDCP layer received in user side RLC record.

L86, identical with L16; And after the PDU that the quilt that the correct receiving target eNodeB of user side RLC entity sends identifies, according to the numbering of the PDU of described record and the SDU that transmits the PDU correspondence that ED point verification received before forwarding ED point whether be out of order SDU, if there is numbering to be delivered to the PDCP layer by reorganization greater than the SDU of the numbering N correspondence of the PDU that is identified, then this SDU is used as and successfully receives, if needs are arranged, then further upgrade corresponding timer or window edge, inform that simultaneously this SDU of PDCP layer is not out of order SDU.

L87, PDCP layer reorder according to the PDCP numbering of the SDU that receives.

L78 is identical with L18.

In order to support the inventive method, the present invention also provides the system that transmits data in a kind of handoff procedure, and referring to shown in Figure 6, it comprises sequencing unit, and link to each other with described sequencing unit submit unit and forwarding ED point notification unit; Further comprise and described first trigger element that the unit links to each other and second trigger element that links to each other with described sequencing unit submitted.

Described first trigger element, it is positioned at the user side rlc layer, when being used for receiving first SDU that target eNode B sends after switching beginning, triggers the described unit of submitting.

The described unit of submitting, it is positioned at the user side rlc layer, is used for submitting SDU to the PDCP layer.

Described second trigger element, it is positioned at the PDCP layer, is used for triggering sequencing unit and beginning ordering when user side carries out the RLC replacement.

Described sequencing unit, it is positioned at the PDCP layer, is used for sorting to submitting the SDU that sends the unit before the forwarding ED point with the PDCP sequence number.

Described forwarding ED point notification unit, it is arranged in source eNodeB, target eNode B and user side RLC, is used for notice and transmits the ED point.

Obviously, those skilled in the art can carry out various changes and modification to the present invention and not break away from the spirit and scope of the present invention.Like this, if of the present invention these are revised and modification belongs within the scope of claim of the present invention and equivalent technologies thereof, then the present invention also is intended to comprise these changes and modification interior.