Summary of the invention
Purpose of the present invention is intended to solve at least one of above-mentioned technological deficiency, particularly solves when reordering with the repeated elimination operation by the control of Flush_timer timer in the prior art, owing to the inaccurate amount of calculation that increases of value or the out of order problem of generation.
For achieving the above object, the present invention one side proposes a kind of control and reorders and the repeated elimination method of operating, may further comprise the steps: receiving terminal (following behavior UE, last behavior target eNB) receive coboundary sequence number SN after switching, described coboundary SN is the coboundary that the SN of out of order data convergence protocol service data cell PDCP SDU possible take place; Described receiving terminal is determined the termination time of permutatation and repeated elimination operation according to the described coboundary SN that receives.
As an embodiment of said method of the present invention, described receiving terminal is a user equipment (UE), and described UE receives coboundary SN and is specially after switching: the source evolution base station eNB sends to target eNB with described coboundary SN by the X2/S1 interface; Described target eNB is when described UE sends data, and the PDCP PDU of described coboundary SN correspondence is sent to described UE as first PDCP PDU.
As an embodiment of said method of the present invention, described receiving terminal is UE, and described UE receives coboundary SN and is specially after switching: described source eNB sends to target eNB with described coboundary SN by the X2/S1 interface; Described target eNB sends to UE by status report with described coboundary SN when described UE sends data.
An embodiment as said method of the present invention, described receiving terminal is UE, described UE is specially receiving coboundary SN after the switching: by the X2/S1 interface during to described target eNB forwarding data, described source eNB is given to described target eNB with the PDCP SDU of described coboundary SN correspondence before preferential at described source eNB; Described target eNB is when described UE sends data, and the PDCP PDU of the described PDCP SDU correspondence that receives is sent to UE as first PDCP PDU.
As an embodiment of said method of the present invention, described receiving terminal is UE, and described UE receives coboundary SN and is specially after switching: described source eNB sends to described UE by switching command message with described coboundary SN.
In the above-described embodiments, the RRC that described coboundary SN is source eNB is when sending switching command message, and the SN of the PDCP SDU of the new RLC PDU correspondence that RLC will send subtracts 1.
An embodiment as said method of the present invention, described receiving terminal is a target eNB, described target eNB is specially receiving described coboundary SN after the switching: described UE is when described target eNB sends data, and the PDCP PDU of coboundary SN correspondence is sent to target eNB as first PDCP PDU.
An embodiment as said method of the present invention, described receiving terminal is a target eNB, described target eNB is specially at the described coboundary SN of reception after the switching: described UE sends to described target eNB by status report with described coboundary SN when described target eNB sends data.
As an embodiment of said method of the present invention, described receiving terminal is a target eNB, and described target eNB receives described coboundary SN and is specially after switching: described UE sends described coboundary SN by switch acknowledgment message to described target eNB.
In the above-described embodiments, the RRC that described coboundary SN is UE is when receiving switching command message, and the SN of the PDCP SDU of the new RLC PDU correspondence that RLC will send subtracts 1.
An embodiment as said method of the present invention, also comprise: startup reorder and repeated elimination operation after, start timer, lower boundary SN is upgraded in the overtime back of the timing of described timer, and the described timer of resetting, described timing preestablishes.
An embodiment as said method of the present invention also comprises: startup reorder and repeated elimination operation after, start timer, the timing of described timer is used to control the required time of next SDU that receives the corresponding PDCP SDU of lower boundary SN; Receive the next SDU of the corresponding PDCP SDU of lower boundary SN at described receiving terminal after, described receiving terminal is updated to the SN of the described SDU correspondence of reception with the lower boundary SN of record, and the described timer of resetting; When described timer expiry, and when not receiving the next SDU of the corresponding PDCP SDU of lower boundary SN, the more described lower boundary SN of new record is the SN of the previous PDCP SDU correspondence that has received of the next SDU gap that does not receive, the described timer of resetting, and continue to receive SDU.
In the above-described embodiments, also comprise: when the lower boundary SN of described receiving terminal record 〉=coboundary SN, stops described reorder and repeated elimination is operated.
The present invention also proposes a kind of control on the other hand and reorders and the repeated elimination operated system, comprise UE, source eNB and target eNB, described UE, be used for when switching the coboundary SN of upstream data is sent to target eNB, and after switching the coboundary SN of downlink data receiving, and downlink data is reordered and termination time of repeated elimination operation according to the coboundary SN control of the downlink data that receives; Described target eNB is used for the termination time that SN control in coboundary is reordered to upstream data and repeated elimination is operated according to the upstream data of described UE transmission; Described source eNB is used for after sending switching command the coboundary SN of downlink data is sent to described UE, or is transmitted to described UE by target eNB.
Further aspect of the present invention also proposes a kind of receiving terminal, be used for reordering and the repeated elimination operation according to the coboundary SN control that receives, comprise receiver module and control module, described receiver module, be used for receiving after switching coboundary SN, described coboundary SN is the coboundary that the SN of out of order PDCP SDU possible take place; Described control module is used for determining the termination time that permutatation and repeated elimination are operated according to the described coboundary SN that described receiver module receives.
As an embodiment of said method of the present invention, when described receiving terminal was UE, the RRC that described coboundary SN is source eNB was when sending switching command message, and the SN of the PDCP SDU of the new RLC PDU correspondence that RLC will send subtracts 1.
As an embodiment of said method of the present invention, when described receiving terminal was target eNB, the RRC that described coboundary SN is UE was when receiving switching command message, and the SN of the PDCP SDU of the new RLC PDU correspondence that RLC will send subtracts 1.
An embodiment as said method of the present invention also comprises time block, is used for upgrading lower boundary SN in the overtime back of timing, and the described timer of resetting, described timing preestablishes.
An embodiment as said method of the present invention, also comprise time block, be used to control the required time of next SDU that receives the corresponding PDCP SDU of lower boundary SN, when described time block overtime, and when not receiving next SDU, the more described lower boundary SN of new record is the SN of the previous PDCP SDU correspondence that has received of the next SDU gap that does not receive, the described timer of resetting, and continuation receives SDU, and when the lower boundary SN 〉=coboundary SN of record, stop reordering and the repeated elimination operation.
The present invention also proposes a kind of eNB, comprises above-mentioned receiving terminal.
The present invention also proposes a kind of UE, comprises above-mentioned receiving terminal.
The present invention is by the transmission of coboundary SN, make receiving terminal can determine the termination time of permutatation and repeated elimination operation according to coboundary SN, therefore need not Flush_timer timer of the prior art, thereby avoid the Flush_timer length of timer that inaccurate caused technological deficiency is set.And the timer that proposes by the present invention, and the method that the timer timing is set also can be avoided in handoff procedure effectively because PDCP SDU is dropped caused deadlock.
Aspect that the present invention adds and advantage part in the following description provide, and part will become obviously from the following description, or recognize by practice of the present invention.
Embodiment
Describe embodiments of the invention below in detail, the example of described embodiment is shown in the drawings, and wherein identical from start to finish or similar label is represented identical or similar elements or the element with identical or similar functions.Below by the embodiment that is described with reference to the drawings is exemplary, only is used to explain the present invention, and can not be interpreted as limitation of the present invention.
For down link and up link, it is also inequality that it produces out of order situation, below just the out of order reason of its generation etc. simply introduced.
For down link:
In down link, for the DRB that is mapped to RLC AM (Data Radio Bearer, Data Radio Bearer), the main task that PDCP will finish in the handoff procedure is that source eNB gives target eNB with following three class PDCP SDU by changeing (forwarding) before the X2/S1 interface, sends to UE by target eNB again.This three class PDCP SDU is:
The first kind, source eNB send to UE, but are not confirmed the SDU of the PDCPPDU correspondence that success receives as yet by UE, and wherein this partial data may successfully be received by UE but not return state report as yet.
The rlc layer of second class, source eNB is treated and handling, but the PDCP SDU of the data correspondence that does not send as yet.
Handling the untreated PDCP SDU of Buddhist monk in the 3rd class, the PDCP layer.
When switching generation, the UE end starts the Flush_timer timer, opens and delivers according to the order of sequence and the repeated elimination function, and above-mentioned data are handled.It is to be noted, cause the PDCP SDU that receives in the UE end PDCP layer handoff procedure take place out of order, need do at the PDCP layer and reorder and after the reason of repeated elimination operation is to receive the handover_command order, the out of order PDCP of the being submitted to layer of RLC SDU that the rlc layer of UE end can be assembled into, and source eNB can resend to UE by target eNB all data that do not receive the confirmation information.Source eNB by target eNB in the data that UE resends, a part is that UE does not receive and successfully needs the data that retransmit, another part is to be held the data (although being out of order) that successfully receive by UE.When UE receives first's data, need do (reordering) operation of reordering with already present out of order PDCP SDU in the PDCP buffering; Need do the repeated elimination operation with the out of order PDCP SDU that exists in the PDCP buffering when receiving the second portion data.
As seen through the above analysis, for the UE of down link, need do and reorder and the PDCP SDU of the data correspondence of repeated elimination operation is the first kind PDCP SDU that the source eNB that receives of UE is given to target eNB before by the X2/S1 interface.
For up link:
In the up link, for the DRB that is mapped to RLC AM, the main task that PDCP will finish in the handoff procedure is that UE does head compression (if configuration) again with following three class SDU and the encryption back sends to target eNB:
The first kind, UE send to source eNB, but are not confirmed the SDU (partial data may successfully be received by source eNB but not return state report as yet) of the PDCP PDU correspondence that success receives as yet by source eNB.
The rlc layer of second class, UE is treated and handling, but the PDCP SDU of the data correspondence that does not send as yet.
The PDCP SDU that is handling in the PDCP layer of the 3rd class, UE.
Similar with down link, doing the reason that reorders with the repeated elimination operation at the PDCP layer is: when switching, source eNB can be given to target eNB before with the out of order PDCP SDU that receives by the X2/S1 interface, can resend to target eNB all data that do not receive source eNB confirmation and switch back UE.In the data that target eNB resends, a part is to switch preceding source eNB not receive and successfully need the data retransmitted at UE, and another part is the data (although being out of order) that source eNB has successfully received, and by being given to target eNB before the X2/S1 interface.When target eNB receives first's data, need do the operation of reordering with already present out of order PDCP SDU in the PDCP buffering; Need do the repeated elimination operation with the out of order PDCP SDU that exists in the PDCP buffering when receiving the second portion data.As seen through the above analysis, need do and reorder and the PDCP SDU of the data correspondence of repeated elimination operation is the first kind PDCP SDU that the UE that receives of target eNB resends.
Can learn by above-mentioned analysis, it is limited needing the out of order data of permutatation and repeated elimination operation control, for down link, out of order data are that source eNB sends to UE, but do not confirmed the data that success receives as yet by UE, this partial data is transmitted to target eNB by source eNB, and is sent to UE again by target eNB; For up link, out of order data are that UE sends to source eNB, but are not confirmed the data that success receives by source eNB as yet, and this partial data sends to target eNB once more by UE.Receiving terminal (UE or target eNB) as long as know need reorder and the coboundary of the lower boundary of the SN of the PDCP SDU of repeated elimination operation and SN just can be good at controlling reordering and heavily eliminate operational processes out of order data, therefore need not Flush_timer timer of the prior art, thereby avoid the Flush_timer length of timer that inaccurate technological deficiency is set.Need reorder and the lower boundary of the SN of the PDCP SDU of repeated elimination operation owing to provide in the present standard, that is: the lower boundary last_submitted_PDCP_RX_SN of reordering window (the present invention is designated hereinafter simply as lower boundary SN).Therefore as long as accessing, receiving terminal need reorder and the coboundary of the SN of the PDCP SDU of repeated elimination operation, that is: the coboundary (Upper_line_outorder_PDCP_SN of the SN of out of order PDCP SDU may take place, the present invention is designated hereinafter simply as coboundary SN) get final product, wherein, as one embodiment of the present of invention, the SN that rlc layer will send the pairing PDCP SDU of RLC PDU that does not also send among source eNB or the UE when described coboundary SN is specially and switches subtracts 1.Be specially:
For down link: coboundary SN be the RRC of source eNB when sending switching command (handover_command), the SN of the PDCP SDU of RLC PDU correspondence that RLC will send will be new (being different from re-transmission) subtracts 1.
For up link: coboundary SN be the RRC of UE when receiving handover_command, the SN of the PDCP SDU of RLC PDU correspondence that RLC will send will be new (being different from re-transmission) subtracts 1.
Certainly the value of the coboundary SN of Uplink/Downlink that the above embodiment of the present invention proposes only is the more excellent implementation of the present invention; also the coboundary of above-mentioned SN can be postponed backward; the time of reordering and heavily eliminating operation with increase; though may increase the computing of receiving terminal; but equally also can reach technique effect of the present invention, the variation of this type also should be included within protection scope of the present invention equally.
In order clearer understanding to be arranged, will be that present invention is described for example with down link and up link respectively below to the present invention.
As shown in Figure 1, reorder and repeated elimination method of operating flow chart, may further comprise the steps for control in the one embodiment of the invention down link:
Step S101, source eNB sends switching command handover_command message to UE, and the SN of the PDCP SDU of the record new RLC PDU correspondence that RLC will send this moment, thereby obtains coboundary SN.
Step S102 sends to receiving terminal UE with the coboundary SN that obtains.Wherein, the present invention proposes multiple mode and above-mentioned coboundary SN can be sent to UE; following variety of way only is the more excellent implementation of the present invention; be not that explanation the present invention only can realize by following proposal; be that the present invention should not be limited to following send mode, other similar send modes also should be protection range of the present invention and contain.Further, can earlier coboundary SN be sent to target eNB, send to UE by target eNB again by source eNB; Perhaps directly send it to UE by source eNB.
As one embodiment of the present of invention, can by the X2/S1 interface described coboundary SN be sent to target eNB by source eNB earlier, target eNB is when UE sends data, and the PDCP PDU of this coboundary SN correspondence is sent to UE as first PDCP PDU.Wherein, S1 is used to connect eNB and mobile management entity/gateway, and X2 is used for the connection between the eNB.
As an alternative embodiment of the invention, can by the X2/S1 interface coboundary SN be informed target eNB by source eNB earlier, target eNB sends to UE by status report with described coboundary SN when UE sends data.
As another embodiment of the present invention, can be when source eNB passes through the X2/S1 interface to the target eNB forwarding data, the PDCP SDU of coboundary SN correspondence at first before is given to target eNB, target eNB is when UE sends data, and the PDCP PDU of this RLC SDU correspondence is sent to UE as first PDCP PDU.
Equally, as another embodiment of the present invention, also can send to UE by handover_command message.In the handover_command message that UE sends, carry described coboundary SN at source eNB, this coboundary SN is reordered as needs and the coboundary of the SN of the PDCPSDU of repeated elimination operation.
Need to prove skew before and after above-mentioned coboundary SN can do according to actual conditions.In addition from foregoing description as can be seen, how to transmit coboundary SN and mainly be agreement between UE, source eNB and the target eNB, therefore also can send above-mentioned coboundary SN to UE by other means, same the present invention also is not limited to above-mentioned four kinds of modes.Those skilled in the art can understand that above-mentioned four kinds of modes only are in order better to understand the present invention, rather than restriction the present invention, therefore other of above-mentioned send mode are changed also should be protection range of the present invention and contain.
Step S103, UE reorders and the repeated elimination operation termination time according to the coboundary SN control PDCP layer that receives.Because UE end PDCP layer is to guarantee can successfully submit to the upper strata according to the order of sequence when source eNB is given to the first kind SDU of target eNB before by the X2/S1 interface receiving, need reorder and control to the PDCP layer reorders and repeated elimination is operated just can be realized in the lower boundary of the PDCP SDU SN of repeated elimination operation and coboundary as long as therefore know.
As shown in Figure 2, reorder and repeated elimination method of operating flow chart, may further comprise the steps for control in the another embodiment of the present invention up link:
Step S201, source eNB sends switching command (handover_command message) to UE.
Step S202, the rrc layer of UE are after receiving switching command, and RLC writes down the SN of the PDCP SDU of the new RLC PDU correspondence that will send this moment, thereby obtains coboundary SN.
Step S203, UE sends to the receiving terminal target eNB with the coboundary SN that obtains.Wherein, the present invention has proposed three kinds of modes too and has sent coboundary SN by UE to target eNB.
As one embodiment of the present of invention, can be by UE when target eNB send data, the PDCP PDU of coboundary SN correspondence is sent to target eNB as first PDCP PDU.
As an alternative embodiment of the invention, can by status report coboundary SN be sent to target eNB by UE when target eNB sends data.
As another embodiment of the present invention, UE confirms that by switching (handover_confirm) message sends coboundary SN to target eNB.Carry coboundary SN at UE in the handover_confirm message that target eNB sends, target eNB reorders this coboundary SN and the coboundary of the SN of the PDCP SDU of repeated elimination operation as needs.Skew before and after same above-mentioned coboundary SN can do according to actual conditions.
Step S204, target eNB reorders and the repeated elimination operation termination time according to the coboundary SN control PDCP layer that receives.Because target eNB will guarantee target eNB and can submit to the upper strata according to the order of sequence, only need know that therefore lower boundary that out of order PDCP SDU SN may take place and coboundary just could realize the control to the PDCP layer reorders and repeated elimination is operated when receiving the first kind PDCP SDU that UE resends.
An embodiment as said method of the present invention, the deadlock situation that occurs in the handoff procedure, one timer can be set, this timer can be got bigger value as timing, same end is reordered and the repeated elimination operation behind this timer expiry, and this timer also can adopt Flush_timer timer of the prior art.But issuable problem is when adopting the Flush_timer timer: overtime or other reasons is dropped if PDCP SDU is owing to discard_timer in the handoff procedure, then can cause the PDCP SDU of its back to delay time to the upper strata and submit.
Therefore, in order to prevent this from occurring, another embodiment of the present invention also proposes a kind of method that prevents deadlock.Also be provided with a timer among same this embodiment, be specially: start timer when current handoff procedure begins, this is timer-operated to be to receive to be right after used time of SDU of the pairing SDU of lower boundary SN back.When this SDU is received, upgrade described lower boundary SN, and the replacement timer.Need to prove that the present invention is not limited to receive SDU at every turn all will upgrade lower boundary SN, but for example also the compartment of terrain upgrade lower boundary SN.If timer expiry, then the corresponding SDU of expression does not successfully receive, and upgrades lower boundary SN so, and the replacement timer.At this moment lower boundary SN is made as the SN of the previous PDCP SDU correspondence that has received of the next SDU gap (gap) that does not receive, may comprise a plurality of continuous SDU that do not receive among one of them SDU gap.This process stops when lower boundary SN>=coboundary SN.At this moment, stop reordering and the repeated elimination operation of PDCP layer.Simultaneously, in order to guarantee the reception of crucial SDU (PDCPSDU that coboundary SN is indicated), uplink downlink can require corresponding receiving terminal return state report after sending this SDU.
In the above-described embodiments, value about timer: the effect of timer is not the termination time that is used for directly control ordering and repeated elimination operation, but prevent that overtime or other reasons abandons the deadlock that occurs to PDCP SDU owing to Discard_timer, so value can be made as the integral multiple of the Discard_timer value of configuration.
The method that the present invention proposes not only can effectively be finished ordering and repeated elimination operation, when avoiding adopting Flush_timer mechanism, thereby amount of calculation increase that causes owing to value is inaccurate and the out of order problem that causes thereof have also been avoided, simultaneously, the present invention also provides the obtaining value method to used timer.
Corresponding to said method, the present invention also proposes a kind of control and reorders and the repeated elimination operated system, its structure chart as shown in Figure 3, this system comprises UE 100, source eNB200 and target eNB 300.UE100 is used for when switching the coboundary SN of upstream data is sent to target eNB 300, and after switching the coboundary SN of downlink data receiving, and downlink data is reordered and termination time of repeated elimination operation according to the coboundary SN control of the downlink data that receives.Target eNB 300 is used for the termination time that SN control in coboundary is reordered to upstream data and repeated elimination is operated according to the upstream data of UE100 transmission.Source eNB200 is used for after sending switching command the coboundary SN of downlink data is sent to UE100, or is transmitted to UE100 by target eNB 300.
The present invention also proposes a kind of receiving terminal, its structure as shown in Figure 4, this receiving terminal can reorder and the repeated elimination operation according to the coboundary SN control that receives, for down link, this receiving terminal is UE; And for up link, this receiving terminal is a target eNB.This receiving terminal 400 comprises receiver module 410 and control module 420, and receiver module 410 is used for receiving coboundary SN after switching, and this coboundary SN is the coboundary that the SN of out of order PDCP SDU possible take place; Control module 420 is used for determining according to the coboundary SN that receiver module 410 receives the termination time of permutatation and repeated elimination operation.Wherein, when described receiving terminal was UE, the SN of the PDCP SDU of the new RLC PDU correspondence that the RLC that described coboundary SN is source eNB will send when sending switching command message subtracted 1; When described receiving terminal was target eNB, the SN of the PDCP SDU of the new RLC PDU correspondence that the RLC that described coboundary SN is UE will send when receiving switching command message subtracted 1.
As an embodiment of said method of the present invention, this receiving terminal also comprises time block 430, be used at the overtime renewal lower boundary of timing SN, and the described timer of resetting, described timing can preestablish, and can avoid occurring in the handoff procedure deadlock.
For above-mentioned time block 430, the invention allows for a kind of implementation method, this time block 430 is used to control the required time of next SDU that receives the corresponding PDCP SDU of lower boundary SN, when time block 430 overtime, and when not receiving next SDU, more the lower boundary SN of new record is the SN of the previous PDCP SDU correspondence that has received of the next SDU gap that does not receive, the replacement timer, and continue to receive SDU, may comprise a plurality of continuous SDU that do not receive among one of them SDU gap.And when the lower boundary SN of receiving terminal 400 record 〉=coboundary SN, stop reordering and the repeated elimination operation.So in this way, not only can avoid the deadlock situation that occurs in the handoff procedure, can also effectively avoid postponing the problem submitted owing to some PDCP PDU is dropped the PDCP PDU that causes its back.
The present invention is by the transmission of coboundary SN, make receiving terminal can determine the termination time of permutatation and repeated elimination operation according to coboundary SN, therefore need not Flush_timer timer of the prior art, thereby avoid the Flush_timer length of timer that inaccurate caused technological deficiency is set.And the timer that proposes by the present invention, and the method that the timer timing is set also can be avoided in handoff procedure effectively because PDCP SDU is dropped caused deadlock.
Although illustrated and described embodiments of the invention, for the ordinary skill in the art, be appreciated that without departing from the principles and spirit of the present invention and can carry out multiple variation, modification, replacement and modification that scope of the present invention is by claims and be equal to and limit to these embodiment.