Wireless chain control layer reduces the method and system that redundant message retransmits
Technical field
The present invention relates to moving communicating field, be particularly related to a kind of LTE (Long Term Evolution, long-term evolution) in the system, in the process of reconstruction of wireless chain control layer protocol entity (Re-establishment procedure), reduce or avoid the method and system of transmitter side re-transmission redundant message.
Background technology
RLC (Radio Link Control, Radio Link control) protocol layer is in the Radio interface protocols stack of LTE, it is a sublayer of L2 (layer 2), be positioned at MAC (Media Access Control, the media access control) on the layer, the rlc protocol layer provides segmentation and retransmits professional with the control data for the user.The function of rlc protocol layer comprises link control, encapsulation and restructuring, cascade, user data transmission, error correction, protocol error detection and reparation etc.Each rlc protocol entity is by RRC (Radio Resource Control, Radio Resource control) dispose and operate with three kinds of patterns, be respectively: transparent mode (TM, Transparent Mode), Unacknowledged Mode (UM, Unacknowledged Mode), affirmation mode (AM, Acknowledged Mode).
ARQ in the affirmation mode (Auto Repeat Request, HARQ), realize to transmitting terminal status report (Status Report) by receiving terminal, transmitting terminal is judged which PDU (Protocol Data Unit according to the ACK_SN among the Status Report, NACK_SN, protocol Data Unit) the receiving end acknowledges receipt of, which PDU or PDU fragment need to retransmit, thereby guarantee the reliability of transfer of data.In 36.322 agreements, send too frequent for fear of Status Report, take interface-free resources, set a T_status_prohibit (status report is forbidden) timer at the receiving terminal of rlc protocol entity, start this timer behind Status Report of every transmission, at the timer run duration, forbid sending Status Report.
At UE (User Equipment, subscriber equipment) side and eNodeB (Evolution NodeB, evolution base station) side, correspondence belongs to each bar logic channel (Logic Channel) of this UE, UE and eNodeB can set up the rlc protocol entity of equity, and this protocol entity is carried out the handling process of rlc protocol layer.The local terminal of describing in this article namely refers to be subordinated among UE or the eNodeB some UE, and the rlc protocol entity of a corresponding specific logic channel, and the opposite end namely is indication above, corresponding same logic channel with this protocol entity, reciprocity rlc protocol entity.
Rlc protocol volume reconstruction process (Re-establishment procedure), refer to the rlc protocol entity, entity resets (Reset) process by the high level indication, in this process, relate to the processing of current uplink and downlink message, the setting of timer, a series of related procedure such as change of protocol status variable.The present invention be directed to the process of reconstruction under the AM affirmation mode.
36.322 in the agreement, at present to the description of the rlc protocol volume reconstruction process of AM pattern as shown in Figure 1: after receiving terminal receives the reconstruction indication of RRC, the message that has received that directly will receive in the sliding window is all delivered to the upper strata, be PDCP (Packet Data Convergence Protocol, PDCP) layer, and no matter whether it is continuous, and can not send Status Report to transmitting terminal this moment.After reconstruction was finished, transmitting terminal need to resend the message that receiving terminal does not have loopback to cross to reply.
Trigger at present the following several classes of Conditional Include of rlc protocol volume reconstruction process:
● switch, indicated by RRC;
● the rlc protocol layer is processed unusual;
● network condition is abominable, repeatedly retransmits all such as certain message to send unsuccessfully.
Fig. 2 has described in the rlc protocol volume reconstruction process, causes the reason of redundant message transmission.As shown in the figure, before process of reconstruction occured, receiving terminal had received that sequence number is 0,1,2,3,7 message, 4,5,6 disappearances.Receive upper strata indication reconstruction, then receiving terminal can all be delivered 0,1,2,3,7 these 5 messages to the PDCP layer.For PDCP, sequence number is that 0,1,2,3 message belongs to the message of receiving continuously, can continue to deliver to the upper strata, and from sequence number 4, then needs to continue afterwards to wait in reconstruction the message of transmitting terminal re-transmission.
Yet in process of reconstruction, receiving terminal does not send Status Report to transmitting terminal, and for transmitting terminal, all messages of sequence number from 0 to 7 are not all received and replied.After rlc protocol volume reconstruction process was finished, transmitting terminal is whole messages of transmission sequence number from 0 to 7 again.After the rlc protocol entity resets of receiving terminal, all state variables and timer make zero, and can't judge that these messages are re-transmissions or new, so still be delivered to PDCP, judge by PDCP whether message repeats.Concerning PDCP, sequence number 0,1,2,3,7 message all are redundant messages, can only abandon.On flow process, because lack the mutual of receiving terminal and transmitting terminal in the process of reconstruction, thereby correctly receive but do not send Status Report and cause transmitting terminal not receive that the message of replying is repeated transmission, has wasted the processing time of interface-free resources and protocol layer because occur rebuilding though cause those receiving terminals.
Discuss among the manuscript CR R2-085804 in nearest agreement, removed the process of reconstruction for single DRB (Data Radio Bear, Data Radio Bearer), replace the mode that UE all rebuilds all special-purpose DRB of this UE.This that is to say that a DRB's is unusual, may cause the redundant message transmission on many DRB, thereby causes the waste of larger interface-free resources.
Summary of the invention
In view of this, main purpose of the present invention is to provide a kind of wireless chain control layer to reduce the method that message retransmits, be used for to solve and to repeat transmitting and receiving terminal behind the rlc protocol volume reconstruction and confirmed the redundant message that receives, cause the technical problem of interface-free resources waste.
Core concept of the present invention is: in the condition that triggers rlc protocol volume reconstruction process, except switching this by the direct condition of initiating of high level, reconstruction under all the other two kinds of conditions, all be by behind the RLC notice high level, initiated by high level again, hence one can see that, but whether the reconstruction of rlc protocol layer look-ahead occurs, therefore, before receiving to rebuild indication, the rlc protocol entity allow each Data Radio Bearer (DRB) that belongs to this UE attempt to send a status report (Status Report) to transmitting terminal, transmitting terminal was just at first disposed the message that these have acknowledged receipt of before receiving the request of reconstruction, after reconstruction is finished, no longer repeat to send, retransmit thereby reduce redundant message.
For achieving the above object, technical scheme of the present invention is achieved in that
A kind of wireless chain control layer reduces the method that message retransmits, and may further comprise the steps:
Steps A: in eNodeB or UE side, when corresponding to the rlc protocol entity detection of a certain logic channel when triggering rlc protocol volume reconstruction unusual, the notice local terminal be subordinated to other rlc protocol entity corresponding with logic channel of same UE or only notify that local terminal is subordinated to same UE with affirmation pattern corresponding to logic channel under the rlc protocol entity;
In the eNodeB side, a plurality of rlc protocol entities that belong to same UE normally operate on same veneer or the digital signal processor, only comprise the rlc protocol entity of this UE in the UE side.No matter be eNodeB side or UE side, detecting the unusual rlc protocol entity of triggering rlc protocol volume reconstruction can notify local terminal other rlc protocol entity corresponding with logic channel by modes such as function call, information communication mechanism or global variable signs, and local terminal need to be rebuild all rlc protocol entities that are subordinated to same UE.
Step B: no matter its status report forbids whether timer moves to the radio link control entity that is in affirmation mode that local terminal is notified, all before described radio link control volume reconstruction to the rlc protocol entity status report (Status Report) of opposite end equity;
In the steps A, if the rlc protocol entity that notes abnormalities only notifies local terminal to be subordinated to the RLC entity under the affirmation mode of being in of same UE, then this step need not judge whether current notified rlc protocol entity is in affirmation mode again; If in the steps A, the rlc protocol entity notice local terminal that notes abnormalities is subordinated to all RLC entities of same UE, need also among the step B then to judge whether current rlc protocol entity is in affirmation mode, and the rlc protocol entity that only is under the affirmation mode just needs status report.Also be in affirmation mode if detect the unusual rlc protocol entity of triggering rlc protocol volume reconstruction in the steps A, then other rlc protocol entity that is in affirmation mode of this rlc protocol entity and local terminal all needs to the opposite end status report.
Step C: after the rlc protocol entity of described opposite end equity is received status report, protocol Data Unit (the Protocol Data Unit that has acknowledged receipt of in the deletion status report, PDU) and service data unit (Service Data Unit, SDU) corresponding to upper strata.
Further, in the steps A, unusually refer to protocol processes mistake or the message of described triggering rlc protocol volume reconstruction retransmit unusually;
Further, among the step B, the radio link control entity that is in affirmation mode that described local terminal is notified is as follows to the step of the rlc protocol entity status report of opposite end equity:
Step B01, judge whether the T_status_prohibit timer moves, if off-duty, then execution in step B02; If B03 is then carried out in operation;
Step B02, send Status Report, execution in step B05 to the rlc protocol entity of opposite end equity;
Step B03, stop the T_status_prohibit timer, then execution in step B04;
Step B04, send Status Report to the rlc protocol entity of opposite end equity;
Step B05, restart the T_status_prohibit timer.
Another object of the present invention is to provide a kind of wireless chain control layer to reduce the system that redundant message retransmits, comprise UE side and eNodeB side, UE side and eNodeB side all comprise chain of command processing unit and user's face processing unit, comprise one or more radio link control entities corresponding with logic channel in user's face processing unit, described radio link control entity comprises:
The entity handles module is for the basic function that realizes the radio link control entity;
Notification module, be used for when during to triggering radio link control volume reconstruction unusual, having the radio link control entity of notifying local terminal to be subordinated to other radio link control entity of same terminal or being in affirmation mode corresponding to the radio link control entity detection of a certain logic channel;
Status report module before rebuilding, be used for the notified radio link control entity that is in affirmation mode of local terminal after receiving described notice, no matter its status report forbids whether timer moves, and all has before described radio link control volume reconstruction to opposite end equity radio link control entity status report.
Further, after the rlc protocol volume reconstruction was finished, the rlc protocol entity only retransmitted unacknowledged message among the Status Report that receives recently.
It should be noted that if because network condition is abominable, then Status Report also possibly can't send to the opposite end, so this scheme is a kind of protection mechanism, whether can comes into force in real time and then depend on the network environment that triggers when rebuilding.
Adopt after the implementation method of the present invention, can allow the rlc protocol volume reconstruction finish after, the protocol entity of transmitting terminal is the transmitting and receiving terminal message of receiving unconfirmed only, avoided receiving terminal received message repeat the transmission, reduced the expense of eating dishes without rice or wine.
Description of drawings
Fig. 1 is the generally speaking realization of rlc protocol volume reconstruction flow process;
Fig. 2 is the schematic diagram that redundant message retransmitted after process of reconstruction was finished;
Fig. 3 is the logical construction schematic diagram of system of the present invention;
Fig. 4 is the building-block of logic of rlc protocol entity in the system of the present invention;
Fig. 5 A is the handling process when the rlc protocol entity detection is unusual to the triggering reconstruction in the present invention's one specific embodiment;
Fig. 5 B is the handling process when the rlc protocol entity detection is unusual to the triggering reconstruction in another specific embodiment of the present invention;
Fig. 6 is the handling process of rlc protocol entity of the present invention after notified;
Fig. 7 is that opposite end of the present invention rlc protocol entity is received Status Report, the handling process before and after rebuilding;
Fig. 8 is the whole sequential flow chart of realizing of process of reconstruction of the present invention.
Embodiment
For making the purpose, technical solutions and advantages of the present invention clearer, by the following examples and with reference to accompanying drawing, the present invention is described in more detail.
Fig. 3 is the logical construction schematic diagram of system of the present invention, comprises UE end and eNodeB end two parts, and protocol hierarchy relation and the module at two ends form basically identical.Two ends all comprise chain of command processing unit and user's face processing unit two parts, and each UE holds user's face processing unit that a correspondence can be arranged at eNodeB, for the treatment of the user face data that is subordinated to same UE.RLC entity in user's face processing unit is used for finishing the wireless chain control layer protocol function, each end might comprise a plurality of service logical channels, therefore it is corresponding with service logical channels to have a plurality of rlc protocol entities, each rlc protocol entity communicates by the rlc protocol entity of the equity of Traffic Channel and opposite end, in the existing protocol, when the rlc protocol entity is detecting when triggering rlc protocol volume reconstruction unusual, can notify the Radio Resource controlled entity in the chain of command processing unit, the Radio Resource controlled entity can be rebuild Indication message to sending for all rlc protocol entities that are subordinated to same UE, after local terminal rlc protocol volume reconstruction is finished, resend again the message data that does not obtain confirming.Among the present invention, the rlc protocol entity is detecting when triggering rlc protocol volume reconstruction unusual, all that can at first notify local terminal are subordinated to the rlc protocol entity of same UE, notified and be in rlc protocol entity under the affirmation mode can be before reconstruction status report to opposite end rlc protocol entity.
Fig. 4 is the logical construction schematic diagram of the rlc protocol entity in the system of the present invention, comprises entity handles module, notification module, status report module before rebuilding.The entity handles module is used for finishing the function of existing protocol wireless chain control layer; Notification module is used for when notifying local terminal other rlc protocol entity corresponding to the rlc protocol entity detection of a certain logic channel during to triggering rlc protocol volume reconstruction unusual; The status report module was used for before local terminal rlc protocol volume reconstruction to opposite end equity rlc protocol entity status report before rebuilding.The entity handles module detects unusual rear notice and rebuilds front status report module and notification module, after the status report module sends other rlc protocol entity that status report messages and notification module be subordinated to from same UE to local terminal and sends abnormity notifying message to the opposite end before reconstruction, the entity handles module will report the Radio Resource controlled entity unusually, and the decision-making of Radio Resource controlled entity is rebuild and sent the reconstruction indication to the entity handles module.
In the present invention's one specific embodiment, suppose to belong at certain eNodeB 5 rlc protocol entities of UE (User Equipment, subscriber equipment), be affirmation mode, the DRB of respectively corresponding 5 kinds of different business comes respectively with DRB1~DRB5.Suppose that the rlc protocol entity receiving terminal of each DRB has received that according to the order of sequence sequence number is 10 messages of 0~9 now, length is 1024 bytes, because do not reach the condition that triggers Status Report, all be not the RLC peer protocol entity transmission Status Report of UE at present to transmitting terminal; It is 10 messages of 0~9 that the reciprocity rlc protocol entity transmitting terminal of each DRB of UE side has sent sequence number, and also having sequence number is that 5 messages of 10~14 are to be sent, and length is 1024 bytes equally.When rlc protocol entity detection corresponding to DRB1 retransmit to protocol processes mistake or message surpass threshold value unusual after, handling process such as Fig. 5 A:
The rlc protocol entity detection of step 5-01:DRB1 surpasses the unusual of threshold value to protocol processes mistake or the re-transmission of a certain message;
The rlc protocol entity of step 5-02:DRB1 is notified all the rlc protocol entities from DRB1 to DRB5 that belong to this UE by the mode of message or function call;
The rlc protocol entity of step 5-03:DRB1 is with the Radio Resource controlled entity of this abnormity notifying local terminal.
In the present invention's one specific embodiment, suppose to belong at certain eNodeB 8 rlc protocol entities of UE (User Equipment, subscriber equipment), the DRB of respectively corresponding 8 kinds of different business comes respectively with DRB1~DRB8.Wherein DRB1~DRB5 is the rlc protocol entity of affirmation mode, and DRB6~DRB8 is the rlc protocol entity of Unacknowledged Mode.Suppose that the rlc protocol entity receiving terminal of each DRB has received that according to the order of sequence sequence number is 10 messages of 0~9 now, length is 1024 bytes, because do not reach the condition that triggers Status Report, the rlc protocol entity of all affirmation modes all is not the RLC peer protocol entity transmission Status Report of UE to transmitting terminal at present; It is 10 messages of 0~9 that the reciprocity rlc protocol entity transmitting terminal of each DRB of UE side has sent sequence number, and also having sequence number is that 5 messages of 10~14 are to be sent, and length is 1024 bytes equally.When rlc protocol entity detection corresponding to DRB1 retransmit to protocol processes mistake or message surpass threshold value unusual after, handling process such as Fig. 5 B:
The rlc protocol entity detection of step 5-11:DRB1 surpasses the unusual of threshold value to protocol processes mistake or the re-transmission of a certain message;
The rlc protocol entity of step 5-12:DRB1 is notified the rlc protocol entity of the affirmation pattern from DRB1 to DRB5 that belongs to this UE by the mode of message or function call, but does not notify the rlc protocol entity of DRB6 to these Unacknowledged Modes of DRB8;
The rlc protocol entity of step 5-13:DRB1 is with the Radio Resource controlled entity of this abnormity notifying local terminal.
For each rlc protocol entity that is informed in from DRB1 to DRB5 (comprise and at first detect wrong rlc protocol entity), carry out following steps as shown in Figure 6:
Step 6-1:RLC protocol entity is notified, learns to detect and may trigger the unusual of rlc protocol volume reconstruction;
Step 6-2: this rlc protocol entity judges that whether T_status_prohibit (Status Disable) timer of self is in run mode, if so, then changes flow process 6-3 over to, otherwise directly jumps to flow process 6-4;
Step 6-3: stop the T_status_prohibit timer;
Step 6-4: send Status Report to the rlc protocol entity of opposite end equity, the ACK_SN that wherein comprises equals 10, namely identifies 0~9 message and all receives;
Step 6-5: start the T_status_prohibit timer.
The rlc protocol entity of opposite end receives after the Status Report, handling process as shown in Figure 7:
Step 7-1:RLC protocol entity is received the Status Report that sends the opposite end;
Step 7-2: according to Status Report, the sequence number that has correctly been received by the opposite end in the transmit queue in the deletion protocol entity is 0~9 PDU, and SDU corresponding to notice upper strata deletion;
Step 7-3: rebuild and finish;
Step 7-4: retransmit still not deleted SDU, i.e. SDU corresponding to the PDU of sequence number 10~14 to opposite end RLC.
In sum, comprise the process of reconstruction of the method for the invention as shown in Figure 8, carry out following steps:
Step 8-1: receiving terminal rlc protocol entity is learnt and is occured to trigger the unusual of rlc protocol volume reconstruction;
Step 8-2: receiving terminal rlc protocol entity sends Status Report to the opposite end;
Step 8-3: after transmitting terminal rlc protocol entity is received Status Report, delete the PDU that is correctly received by the opposite end in the transmit queue, and SDU corresponding to notice upper strata deletion;
Step 8-4: receiving terminal and transmitting terminal rlc protocol entity are all received the reconstruction indication on upper strata;
Step 8-5: receiving terminal rlc protocol entity is with all messages in the reception buffer zone, and no matter whether it all delivers to PDCP continuously;
Step 8-6:RLC protocol entity is rebuild and is finished;
Step 8-7: transmitting terminal rlc protocol entity sends to the opposite end and not yet obtains the PDU that confirms.
Can see that from the description of this flow process because before receiving the reconstruction indication, receiving terminal and transmitting terminal have carried out the mutual of a Status Report, so that transmitting terminal can be deleted the confirmed PDU of receiving terminal.Only can transmit the PDU that those do not obtain confirming afterwards in reconstruction like this, avoid a large amount of re-transmissions of redundant message.In this embodiment, 5 DRB, each DRB do not repeat transmission sequence number after reconstruction be 10 PDU messages of 0~9, and each length is 1024 bytes, and namely in the transfer of data of eating dishes without rice or wine to have reduced 50K, effect is quite obvious.
The above is preferred embodiment of the present invention only, is not for limiting protection scope of the present invention.