WO2009086679A1 - Method for reset control of radio link control entity - Google Patents

Abstract

The invention discloses a method for reset control of radio link control entity which comprises: setting a corresponding discard timer for each Packet Data Convergence Protocol service data unit (PDCP SDU) on Packet Data Convergence Protocol (PDCP) layer; starting the discard timer when the upper layer of the PDCP layer transfers the PDCP SDU; stopping the discard timer, setting and starting an RLC reset timer when a first predetermined condition is fulfilled, and triggering the reset procedure of the RLC entity when a second predetermined condition is fulfilled. The first predetermined condition is: the PDCP SDU has been transferred to the RLC layer and the RLC sequence number has been assigned before the discard timer expires. The second predetermined condition is: when the RLC reset timer expires, there exist RLC PDUs which are not transferred successfully among all of the RLC PDUs.

Description

 TECHNICAL FIELD The present invention relates to the field of digital mobile communication technologies, and in particular to a reset control method for a radio link control entity in a wireless communication system. The radio link control layer (Radio Link Control, RLC for short) of the third-generation mobile communication system Wideband Code Division Multiple Access (WCDMA) wireless interface includes three modes of RLC entities: transparent Mode (Transparent Mode, TM for short), Unacknowledged Mode (UM) and Acknowledged Mode (AM) „ TM RLC entity and UM RLC entity can be configured to send RLC entities or receive RLC entities. The RLC entity sends a RLC PDU when the RLC entity is sent, and the RLC entity receives the RLC PDU. The AM RLC entity includes a sender and a receiver, where the sender AM RLC The entity sends the RLC PDU, and the receiving end AM RLC entity receives the RLC PDU. The AM RLC entity provides a reliable data transmission service by using an Automatic Retransmission Request (ARQ) mechanism.

The transmitters of the TM RLC entity, the UM RLC entity, and the AM RLC entity support a timer-based radio link control radio data control (Radio Link Control Service Data Unit, RLC SDU) discarding function (SDU Discard), In addition, the AM RLC entity also supports the SDU drop function based on the maximum number of transmissions of the RLC PDU. In the timer-based SDU discarding function, the timer is set at the RLC layer. When the RLC layer receives an RLC SDU from the upper layer protocol layer, it starts a timer (Timer_Discard) whose value is configured by the upper layer protocol layer. If the relevant RLC PDU cannot be successfully sent before the timer expires or after several times of retransmission, the relevant RLC PDU is discarded from the buffer of the RLC PDU to avoid buffer overload. TM RLC entities and UM RLC entities can be configured by the higher layer protocol layer to use SDU

The Discard function does not use the SDU Discard function. When the UM RLC entity is configured not to use the SDU Discard function, the relevant RLC PDU can be discarded only when the transmit buffer is full. When the TM RLC entity is configured not to use the SDU Discard function, when the sender receives a new SDU from the upper layer protocol layer, it can discard the previous transmission interval (Transmission Timer Interval, Referred to as TTI), the SDU is connected to 4. When the TM RLC entity/UM RLC entity is configured to use the SDU Discard function, the "Timer based (discipline based discard, without explicit signaling) discarding, mechanism is used. The transmitting end receives from the higher layer protocol layer. Each SDU that is sent initiates a timer to monitor the transmission time of the SDU. When the transmission time exceeds the configured value, the sender discards the SDU, and does not need to explicitly signal the TM RLC or UM RLC entity of the receiving end.

The AM RLC entity must be configured to use the SDU Discard function and support three SDU Discard mechanisms. These three mechanisms are: "Timer based discard (with explicit signaling) discards", " SDU discard after MaxDAT number of transmissions " ^ " exceeds the maximum number of transmissions (No-discard after MaxDAT number of transmissions),.

The basic principle of the "Timer-based Discarding with Explicit Signaling" mechanism is: The sender initiates a timer (Timer- Discard) for each SDU received from the higher layer protocol layer. When the timer expires, it sends The end discards the SDU. When the "Send MRW" function is configured or one or more fragments of the SDU that need to be discarded have been submitted to the underlying protocol layer, the receiving end discards the corresponding RLC PDU by explicitly signaling. The basic principle of the "discard after exceeding the maximum number of transmissions" mechanism is: When the number of times an AM RLC data PDU (AMD PDU) is scheduled to be sent reaches the maximum number of transmissions, MaxDAT, the sender discards the relevant SDU and passes the explicit letter. Let the receiving end discard the corresponding RLC PDU. The basic principle of the mechanism of "Do not discard after exceeding the maximum number of transmissions" is: When the number of times an AMD PDU is scheduled to be sent reaches the maximum number of transmissions MaxDAT, the sender initiates an RLC Reset (RLC Reset) process.

The "Send Mobile Receive Window (Send MRW)" function is used by the AM RLC entity to discard the SDU and then explicitly signal the receiving end to discard the corresponding AMD PDU to update the receiving window. The basic principle is shown in Figure 1: The sender sets the "Mobile Receive Window Super Field (MRW SUFI)" after discarding the relevant SDU, which contains the necessary information of the discarded SDU, and includes the MRW SUFI in the Status Protocol Data Unit Status. The receiving end of the AM RLC entity is notified in the PDU, and the timer Timer_MRW is started. After the receiving end correctly receives the Status PDU containing the MRW SUFI, it discards the corresponding AMD PDU according to the information in the MRW SUFI and delivers the other related AMD PDUs to the upper layer protocol layer, and sets the mobile receiving window to confirm the super field MRW_ACK SUFI to the transmitting end. AM RLC entity response. After the transmitter AM RLC entity correctly receives the MRW_ACK SUFI, it updates the transmission window according to the information therein, stops the timer Timer_MRW, and completes the Send MRW process. If the Timer MR_Timeout is not completed when the timer expires - MRW is over, then at MRW When the transmission of SUFI does not reach the maximum number of times MaxMRW, the sender resets MRW SUFI and sends it to the receiver. When the transmission of MRW SUFI has reached the maximum number of times, the sender terminates the Send MRW process and initiates the RLC reset process. .

The RLC reset process is used to reset two peer AM RLC entities. The basic principle of the process is shown in Figure 2. During the RLC reset process, the Hyper Frame Number (HFN) used by the encryption function is required. Synchronize between two AM RLC entities. When the RLC reset process is initiated, the sender stops sending all AMD PDUs or Status PDUs, ignores all received AMD PDUs or Status PDUs, sets the reset protocol data unit (RESET PDU) and submits it to the underlying protocol layer, and starts the timer Timer— RST. After receiving the RESET PDU correctly, the receiving end submits a reset acknowledgement protocol data unit (RESET ACK PDU) to the underlying protocol layer, and performs RLC reset, including initializing related state variables, stopping related timers, resetting related configuration parameters, and discarding related RLC SDUs. With RLC PDUs, etc. After the sender receives the RESET ACK PDU correctly, it performs an RLC reset, including initializing the relevant state variables, stopping the relevant timer, resetting the relevant configuration parameters, discarding the relevant RLC SDUs and RLC PDUs, etc., to complete the RLC reset process. If the RLC reset process is not completed when the timer Timer-RST expires, if the transmission of the RESET PDU does not reach the maximum number of transmissions MaxRST, the sender resets the RESET PDU transmission, and the transmission of the RESET PDU reaches the maximum number of transmissions. Next, the sender reports an unrecoverable error to the upper layer protocol layer. The third-generation mobile communication Long Term Evolution (LTE) system radio interface radio link control layer (Radio Link Control, RLC for short) also includes three types of RLC entities: TM RLC entity, UM RLC entity, And AM RLC entities.

The LTE radio interface also supports the timer-based SDU Discard function. The SDU discard timer is set in the Packet Data Convergence Protocol (PDCP). The PDCP layer is a high-level protocol layer located above the RLC layer. Each PDCP SDU is configured with a timer that is started when a high layer of the PDCP layer delivers a packet. When the timer expires, the PDCP SDU that has not been submitted to the RLC layer and/or has been submitted to the RLC layer may be discarded. There is no PDCP SDU with the RLC serial number assigned at the RLC layer. For the PDCP SDU that has been submitted to the RLC layer and has been assigned the RLC serial number at the RLC layer, it can be discarded. In the 3rd Generation Partnership Project , referred to as 3GPP) is still under study. There are currently two options:

(-) The PDCP SDU is not discarded. The subsequent process is to be studied. For AM RLC, the solution is as follows. Set a discard timer for each RLC PDU. If the timer expires, After receiving the acknowledgment response from the receiving end, the corresponding RLC SDU is discarded, and the sending window is updated;

(2) Discarding the PDCP SDU, the subsequent process follows the "Send MRW" function of the WCDMA radio interface of the third generation mobile communication system. In the process of implementing the present invention, the inventors of the present invention have found that the first solution has the following disadvantages: It may cause buffer overload, and for what proportion of SDUs may exceed the quality of service (QoS) requirements. The packet delay budget ("packet delay budget", or PDB for short) is not clear. The solution 2 has the following two disadvantages: First, when the SDU discard timer expires, a part of the corresponding RLC PDU has been sent successfully. The timer timeout may be caused by the scheduling delay, that is, the PDCP SDU is The PDCP layer has a large retention time in the buffer. In this case, if the SDU discarding is performed immediately, the radio resources will be wasted and unfair; the second is the complexity of the "Send MRW" mechanism.

The RLC reset function of the LTE radio interface is also under study. The current research conclusion is that the inter-base station handover will trigger the RLC reset, and no research results have been obtained for other trigger conditions. In the existing scheme, there are two views on the flow of the RLC reset itself, as shown in FIG. 3: First, the RLC reset mechanism of the WCDMA radio interface of the third generation mobile communication system is used, that is, the RESET PDU is used by the transmitting end in the RLC layer. The receiving end resets; the second is that when the RLC reset triggering condition is met, the RLC layer instructs the higher layer radio resource control layer (Radio Resource Control, RRC for short) to notify the RLC entity corresponding to the receiving end to reset by the RRC layer signaling. As described above, for the LTE radio interface, the SDU Discard solution may cause problems such as buffer overload, waste of radio resources, and a mechanism for "sending the mobile receiving window", and the research result of the RLC reset technology is only the base station. The inter-switching will result in an RLC reset, but not for other reset conditions. Therefore, further research on RLC reset techniques is needed. SUMMARY OF THE INVENTION The present invention has been made in view of the problems that the SDU Discard technology of the LTE radio interface existing in the related art may cause buffer overload, waste of radio resources, and a mechanism of "sending a mobile reception window". Accordingly, the present invention is directed to a reset control method for a radio link control entity that can effectively overcome at least one of the above problems. According to an aspect of the present invention, there is provided a reset control method of a radio link control entity for confirming a reset control of a mode radio link control entity. A reset control method of a radio link control entity according to an embodiment of the present invention includes the following processing: For each PDCP SDU, a corresponding discard timer is set for it at the PDCP layer, and discarding is started when a PDCP SDU is delivered at a high layer of the PDCP layer a timer; if the first predetermined condition is met, stopping the discard timer, setting and starting the radio link control reset timer, and triggering the radio link control entity reset procedure if the second predetermined condition is met; The first predetermined condition is: before the drop timer expires, the PDCP SDU has been delivered to the radio link control layer and the radio link control sequence number has been allocated; the second predetermined condition is: the radio link control reset timer is super At present, there are radio link control protocol data units that are not successfully transmitted in all radio link control protocol data units involved in the PDCP SDU. Preferably, after the discard timer is started, the method further includes: discarding the service data unit if the third predetermined condition is met; wherein the third predetermined condition is: when the discard timer expires, the PDCP SDU has not been submitted yet To the radio link control layer; or, when the discard timer expires, the PDCP SDU has been delivered to the radio link control layer, but the radio link control sequence number has not been assigned yet. Preferably, after the radio link control reset timer is started, the method further includes: stopping the radio link control reset timer if the fourth predetermined condition is met; wherein the fourth predetermined condition is: radio link control All radio link control protocol data units involved in the PDCP SDU have been sent successfully before the reset timer expires. The duration of the reset timer is configured by a higher layer protocol layer, and the duration is configured to be equal to an integer multiple of the automatic retransmission request loopback time. Preferably, in the case of a plurality of PDCP SDUs, in a case where both of the first predetermined conditions are satisfied: respectively setting and starting a radio link control reset timer corresponding to each PDCP SDU; when one of the radio links controls the reset timing When the radio link control entity reset process is triggered, all other radio link control reset timers that have been started are stopped; when the radio link control entity reset process is completed, other radio link control that stops and stops is restarted. Reset the timer. Or, preferably, in the case of a plurality of PDCP SDUs, in a case where both of the first predetermined conditions are satisfied: setting and starting a radio link control reset timer corresponding to the earliest stopped discard timer; When the control reset timer is stopped before the timeout, the radio link control reset timer corresponding to the next earliest discarded discard timer is set and started. In addition, in the case of multiple PDCP SDUs, after the radio link control entity reset timer corresponding to one of the PDCP SDUs triggers the radio link control entity reset process, the discard timing corresponding to other PDCP SDUs that have been started is not stopped. Device. Or, in the case of multiple PDCP SDUs, after the radio link control entity reset timer corresponding to one of the PDCP SDUs triggers the radio link control entity reset process, the drop timer corresponding to the other PDCP SDUs that have been started is stopped, and After the radio link control entity reset process is completed, the discard timer corresponding to the other PDCP SDUs that are stopped is restarted. According to another aspect of the present invention, a reset control method of a radio link control entity is also provided. The reset control method according to an embodiment of the present invention includes the following processing: For each PDCP

SDU, which sets a corresponding drop timer for the PDCP layer, and starts the discard timer when the PDCP SDU is delivered by the upper layer of the PDCP layer; if the first predetermined condition is met: If the radio link control entity is in the acknowledge mode a radio link control entity, stopping the discard timer, setting and starting a radio link control reset timer, and triggering a radio link control entity reset procedure if the second predetermined condition is met; if the radio link control entity is non- The acknowledgment mode radio link control entity or the transparent mode radio link control entity discards the service data unit; wherein, the first predetermined condition is: before the discard timer expires, the PDCP SDU has been delivered to the radio link control layer and The radio link control sequence number has been allocated; the second predetermined condition is: when the radio link control reset timer expires, there are radio link control protocol data that are not successfully transmitted in all radio link control protocol data units involved in the PDCP SDU unit. Preferably, after the discard timer is started, the method further includes: discarding the service data unit if the third predetermined condition is met; wherein the third predetermined condition is: when the discard timer expires, the PDCP SDU has not been submitted to The radio link control layer; or, when the discard timer expires, the PDCP SDU has been delivered to the radio link control layer, but the radio link control sequence number has not been assigned yet. Further preferably, after the radio link control reset timer is started, the method further includes: stopping the radio link control reset timer if the fourth predetermined condition is met; wherein the fourth predetermined condition is: the radio link All radio link control protocol data units involved in the PDCP SDU have been successfully transmitted before the control reset timer expires. According to the above at least one technical solution provided by the present invention, by setting a new radio link control trigger condition, it is possible to prevent the SDU from staying in the buffer for too long. The buffer overload problem can also avoid the waste of wireless resources and unfairness caused by the immediate discarding of SDUs. At the same time, it can avoid the complicated "send mobile receiving window"mechanism; in addition, compared with related technologies In the method of setting a discard timer for each RLC PDU, the present invention can reduce the number of timers required by setting a discard timer for each PDCP SDU, thereby reducing the processing complexity and processing overhead. Other features and advantages of the invention will be set forth in the description which follows, and The objectives and other advantages of the invention will be realized and attained by the <RTI The drawings are intended to provide a further understanding of the invention, and are intended to be a part of the description of the invention. In the drawings: FIG. 1 is a schematic diagram of a function of a "send mobile reception window (Send MRW)" in a third generation mobile communication system WCDMA according to the related art; FIG. 2 is a schematic diagram of an RLC reset process according to the related art; 3 is a flowchart of an RLC reset procedure according to the related art; FIG. 4 is a flowchart of a reset control method of a radio link control entity according to Embodiment 1 of the present invention; FIG. 5 is a radio link control entity shown in FIG. FIG. 6 is a flowchart of an example of a reset control method of a radio link control entity according to Embodiment 1 of the present invention; FIG. 7 is a radio link control entity according to Embodiment 2 of the present invention; Flowchart of the reset control method; FIG. 8 is a detailed processing flow of the reset control method of the radio link control entity shown in FIG. 9 is a flow chart showing an example of a reset control method of a radio link control entity according to Embodiment 2 of the present invention. DETAILED DESCRIPTION As described above, a Radio Link Control Layer (RLC) includes three types of RLC entities, namely, TM RLC (RLC in Transparent Mode), UM RLC (RLC in Non-Confirmed Mode), and AM RLC (Acknowledge Mode) RLC). In addition, for the LTE radio interface, the existing SDU Discard scheme may cause problems such as buffer overload, waste of radio resources, and a mechanism for "sending the mobile receiving window", and the research result of the RLC reset function is only the base station. An inter-switch will trigger an RLC reset. In view of this, the present invention provides a reset control method for a radio link control entity for the above three types of RLC entities, which provides a new SDU Discard scheme and provides a new reset trigger condition. , can effectively solve the above problems. The preferred embodiments of the present invention are described in the following with reference to the accompanying drawings, which are intended to illustrate and illustrate the invention. Method Embodiment 1 First, for the AM RLC, the embodiment of the present invention provides a reset control method for a radio link control entity, which is used for reset control of an AM RLC. As shown in FIG. 4, the method for resetting a radio link control entity according to an embodiment of the present invention includes the following processes: (Step S402-Step S404) Step S402: For each PDCP SDU, set a corresponding discard for the PDCP layer. Discarding the timer (Timer_Discard), and starting the discard timer when the PDCP SDU is delivered by the upper layer of the PDCP layer; Step S404: Stop the discard timer when the first predetermined condition is met, and set and start the RLC reset timer (Timer_RESET) And triggering the radio link control entity reset procedure if the second predetermined condition is met. In the case of multiple PDCP SDUs, after the radio link control entity reset timer corresponding to one of the PDCP SDUs triggers the radio link control entity reset process, the corresponding PDCP SDU corresponding discards may be stopped or not stopped. Timer. In the case of a stop, After the radio link control entity reset process is completed, the discard timer corresponding to the other PDCP SDUs that are stopped is restarted. For the RLC reset timer, the duration can be configured by a higher layer protocol layer (for example, the RC layer), and the duration is configured to be equal to an integer multiple of the automatic repeat request (ARQ) Round Trip Time (RTT). For the RLC reset process, the transmitting end AM RLC entity may use the RESET control PDU to notify the receiving end of the AM RLC reset or the transmitting end AM RLC entity to indicate its higher layer protocol layer RRC, and the RRC signaling control receiving end AM RLC reset. The respective predetermined conditions and their corresponding processes described above will be further described below in conjunction with FIG. Step S502 is the same as step S402. The processing under the first predetermined condition corresponds to step S506 in FIG. 5, and the processing under the second predetermined condition corresponds to step S510 in FIG. The first predetermined condition is: before the drop timer expires, the PDCP SDU has been delivered to the RLC layer and the RLC sequence number has been allocated; the second predetermined condition is: when the RLC reset timer expires, the PDCP SDU is involved. There are no RLC PDUs in all Radio Link Control Protocol Data Units (RCC PDUs) that have not been successfully transmitted. In addition, after the discard timer is started, the above method further includes the following processing: in a case where the third predetermined condition is satisfied (the processing under the third predetermined condition corresponds to step S504 in FIG. 5), the service data unit is discarded (step S504); wherein, the third predetermined condition is: when the discarding timer expires, the PDCP SDU has not been submitted to the RLC layer; or, when the discarding timer expires, the PDCP SDU has been delivered to the RLC layer, but the RLC serial number has not been allocated yet. . After the RLC reset timer is started, the method further includes: stopping the RLC reset timer if the fourth predetermined condition is satisfied (the processing under the fourth predetermined condition corresponds to step S508 in FIG. 5) (step S508) The fourth predetermined condition is: Before the RLC reset timer expires, all RLC PDUs involved in the PDCP SDU have been successfully sent. Example 1: Reset Control Process of AM RLC Entity FIG. 6 is a flowchart showing a reset control process of an AM RLC entity in the reset control method of Embodiment 1 of the present invention. As shown in FIG. 6, the reset control process of the AM RLC entity includes the following processing: Step S601, the PDCP layer connects the 4t PDCP SDU from the upper layer; Step S602, the PDCP layer sets and starts an SDU discard timer Timer-Discred for each PDCP SDU. Step S603, the PDCP layer performs related processing, for example, performs header compression, encryption, and delivery to the RLC layer for the PDCP SDU. Step S604 The RLC layer performs related processing, for example, receiving a PDCP SDU from the PDCP layer, performing segmentation, concatenation, adding header information, submitting RLC PDUs to the bottom layer, receiving and processing a status report of the receiving terminal AM RLC entity, and the like; Step S605, Determine if the Timer-Discred expires before the PDCP SDU submits to the RLC layer and assigns the RLC sequence number? If the determination result is yes, proceed to step S606; otherwise, proceed to step S607; step S606, discard the corresponding PDCP SDU/PDU, and return to step S601; step S607, after assigning the RLC serial number, stop the corresponding Timer - Discard, set and start the RLC reset timer Timer - RESET, proceeds to step S608; Step S608, determines whether the RLC reset timer Timer_RESET timeout, if the determination is yes, then proceeds to step S609; otherwise, proceeds to step S610; Step S609, if at least one of all the RLC PDUs involved in the PDCP SDU is not successfully sent (for example, the acknowledgment response message of the peer AM RLC entity is not received), the RLC reset process is triggered; the PDCP layer may be notified to stop before the RLC is reset. The SDU discarding timer corresponding to all the PDCP SDUs in the current buffer is notified to the PDCP to restart the PDCP SDU timer corresponding to all PDCP SDUs in the current buffer after the RLC is successfully reset. Then, the process returns to step S601; All RLC PDUs involved in the PDCP SDU have been sent successfully before the RLC reset timer Timer_RESET times out (for example, all received) End of the AM RLC entity acknowledgment response message), then the RLC reset timer is stopped Timer- RESET; then returns to step S601. In addition, preferably, for the case of multiple PDCP SDUs, in the case that both the first predetermined condition is satisfied, the setting and starting of the reset timer may be at least the following two ways: (Mode 1) respectively set and start a radio link control reset timer corresponding to each PDCP SDU; when one of the radio link control reset timers triggers the radio link control entity reset process, the stop has been started. All other radio link control reset timers. After the reset is complete, restart all other radio link control reset timers that were stopped. And so on. Taking the example shown in FIG. 6 as an example, before the above-mentioned RLC reset timer Timer_RESET times out, if other PDCP SDUs have been submitted to the RLC layer, and the RLC sequence number has been allocated at the RLC layer, the RLC sequence is allocated. After the number, stop the corresponding Timer-Dissard and start the corresponding RLC reset timer Timer-RESET. If the earliest Timer-RESET timeout triggers the RLC reset process, all other activated Timer_RESET timers are stopped. (Method 2:) Set and start the radio link control reset timer corresponding to the earliest stopped discard timer; set and start the next earliest when the activated radio link control reset timer is stopped before the timeout The radio link control reset timer corresponding to the dropped discard timer. Still taking the example shown in FIG. 6 as an example, before the above-mentioned RLC reset timer Timer_RESET times out, for the AM RLC entity, if other PDCP SDUs have been submitted to the RLC layer, and the RLC has been allocated at the RLC layer. The serial number stops the corresponding Timer-Dissard after the RLC serial number is assigned, but does not set a new RLC reset timer Timer_RESET, that is, only one RLC reset timer Timer_RESET is active. In this case, it is necessary to record the PDCP SDU of the discarded timer Timer-Discred before the Timer-RESET timeout. If the Timer_RESET is stopped before the timer expires, the PDCP corresponding to the earliest stopped SDU Discard timer is restarted. SDU Timer - RESET timer, and so on. Method embodiment two

In addition, the embodiment of the present invention further provides a reset control method for a radio link control entity. As shown in FIG. 7, the reset control method according to this embodiment of the present invention includes the following processes: (Step S702 - Step S704-2) Step S702, for each PDCP SDU, a corresponding discard timer is set for the PDCP layer. And starting the discarding timer when the PDCP SDU is delivered by the upper layer of the PDCP layer; Step S704-1, if the radio link control entity is the acknowledgment mode radio link control entity, the discard timer is stopped if the first predetermined condition is met , set up and start wireless link control Resetting the timer, and triggering the radio link control entity reset process if the second predetermined condition is met; step S704-2, if the first predetermined condition is met, if the radio link control entity is not acknowledging The mode of the radio link control entity or the transparent mode radio link control entity discards the service data unit. The respective predetermined conditions and their corresponding processes described above will be further described below in conjunction with FIG. Step S802 is the same as step S702. The processing under the first predetermined condition corresponds to step S806 in FIG. 8, and the processing under the second predetermined condition corresponds to step S810 in FIG. The first predetermined condition is similar to the method embodiment 1. The PDCP SDU has been delivered to the radio link control layer and the radio link control sequence number has been allocated before the discard timer expires. Compared with the flow of FIG. 5, in the case where the flow shown in FIG. 8 satisfies the first condition, different RLC entities correspond to different processes. If it is a TM RLC, UM RLC entity, it proceeds to step S804, and if it is an AM RLC entity, it proceeds to step S806. The second predetermined condition is as follows: When the radio link control reset timer expires, there are radio link control protocol data units that are not successfully transmitted in all radio link control protocol data units involved in the PDCP SDU. In addition, after the discard timer is started, the above method further includes the following processing: in a case where the third predetermined condition is satisfied (the processing under the third predetermined condition corresponds to step S804 in FIG. 8), the service data unit is discarded (step S804). The third predetermined condition is: When the discard timer expires, the PDCP SDU has not been submitted to the RLC layer; or, when the discard timer expires, the PDCP SDU has been delivered to the RLC layer, but the RLC sequence number has not been allocated yet. After the RLC reset timer is started, the above method further includes: stopping the RLC reset timer if the fourth predetermined condition is satisfied (the processing under the fourth predetermined condition corresponds to step S808 in FIG. 8) (step S808) The fourth predetermined condition is: Before the RLC reset timer expires, all RLC PDUs involved in the PDCP SDU have been successfully sent. The details of this embodiment can be understood by referring to the flowcharts of FIG. 7 and FIG. 8 and the method embodiment 1. The same or similar portions will not be repeatedly described herein. ' Example 2: RLC SDU Drop Flow for UM RLC or TM RLC Entity Flowchart 9 illustrates the RLC SDU discard procedure for a UM RLC or TM RLC entity of the reset control method of Embodiment 2 of the method of the present invention. As shown in FIG. 9, the δ port includes the following processing: Step S901: The PDCP layer receives the PDCP SDU from the upper layer; Step S902, the PDCP layer sets and starts the SDU discard timer Timer-Discred for each PDCP SDU; Step S903, the PDCP layer performs correlation Processing: Performing operations such as header compression, encryption, and delivery to the RLC layer for the PDCP SDU; Step S904, the RLC layer performs related processing: receiving PDCP SDU from the PDCP layer, performing segmentation, concatenation, adding header information, and submitting to the bottom layer The RLC PDU, the status report to the peer AM RLC entity, the status report of receiving and processing the peer AM RLC entity, and the like; Step S905, determining whether the Timer-Discred has timed out? If the result of the determination is YES, the process goes to step S906; otherwise, the process returns to step S901; in step S906, the relevant PDCP SDU/PDU is discarded, and the process returns to step S901. That is, PDCP SDU/PDU discarding is performed regardless of whether the PDCP SDU has been submitted to the RLC layer and the RLC sequence number is assigned. According to the foregoing at least one technical solution provided by the present invention, by setting a new radio link control trigger condition, the buffer overload problem caused by the SDU staying in the buffer for too long can be avoided, and the buffer overload problem can also be avoided. The SDU immediately discards the waste of wireless resources and unfairness, and at the same time avoids the complicated "send mobile receive window"mechanism; in addition, a drop timer is set for each RLC PDU compared to the related art. The method of the present invention can reduce the number of timers required by setting a discard timer for each PDCP SDU, thereby reducing the processing complexity and processing overhead. The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

Claim A reset control method for a radio link control entity, which is used for confirming a reset control of a mode radio link control entity, and includes:  For each packet data convergence protocol layer service data unit, ie, a PDCP SDU, a corresponding drop timer is set for it at the packet data convergence protocol layer, and the drop timing is initiated when the PDCP SDU is delivered by a higher layer of the PDCP layer Device  If the first predetermined condition is met, the discarded discard timer is stopped, the radio link control reset timer is set and started, and the wireless link control entity reset procedure is triggered if the second predetermined condition is met;  The first predetermined condition is: before the drop timer expires, the PDCP SDU has been delivered to the radio link control layer and the radio link control sequence number has been allocated; the second predetermined condition is: When the radio link control reset timer expires, there are radio link control protocol data units that are not successfully transmitted in all radio link control protocol data units involved in the PDCP SDU. The reset control method according to claim 1, wherein after the discarding timer is started, the method further comprises:  If the third predetermined condition is met, the service data unit is discarded; wherein the third predetermined condition is: when the discard timer expires, the PDCP SDU is not yet delivered to the radio link control layer. Or, when the timer is discarded, the PDCP SDU has been delivered to the radio link control layer, but the radio link control sequence number has not been allocated yet. The reset control method according to claim 1, wherein after the wireless link control reset timer is started, the method further includes:  Stopping the radio link control reset timer if the fourth predetermined condition is met; The fourth predetermined condition is that all radio link control protocol data units involved in the PDCP SDU have been successfully sent before the radio link control reset timer expires. The reset control method according to claim 1, wherein the duration of the reset timer is configured by a higher layer, a layer, and the duration is configured to be equal to an integer multiple of an automatic retransmission request loopback time. . 5. The reset control method according to claim 1, wherein, in the case of a plurality of PDCP SDUs, in a case where both of the first predetermined conditions are satisfied:  Setting and starting a radio link control reset timer corresponding to each PDCP SDU respectively; when one of the radio link control reset timers triggers the radio link control entity reset process, stopping all other devices that have been started Radio link control reset timer;  The other radio link control reset timer that is stopped is restarted in the case where the radio link control entity reset procedure is completed. 6. The reset control method according to claim 1, wherein, in the case of a plurality of PDCP SDUs, in a case where the first predetermined condition is satisfied:  Setting and starting a radio link control reset timer corresponding to the earliest stopped discard timer;  In case the activated radio link control reset timer is stopped before the timeout, the radio link control reset timer corresponding to the next earliest stopped discard timer is set and started. The method for controlling a radio link control entity according to claim 1, wherein, in the case of a plurality of PDCP SDUs, a radio link control entity reset timer corresponding to one of the PDCP SDUs triggers a radio chain After the path control entity resets the process, the drop timer corresponding to other PDCP SDUs that have been started is not stopped. 8. The method for controlling a radio link control entity according to claim 1, wherein, in the case of a plurality of PDCP SDUs, a radio link control entity reset timer corresponding to one of the PDCP SDUs triggers a radio chain After the path control entity resets the process, the drop timer corresponding to the other PDCP SDUs that have been started is stopped, and after the radio link control entity reset process is completed, the drop timer corresponding to the other PDCP SDUs that are stopped is restarted. A reset control method for a radio link control entity, comprising:  For each PDCP SDU, a corresponding drop timer is set for it at the packet data convergence protocol layer, and the discard timer is started when the PDCP SDU is delivered by the upper layer of the PDCP layer;  In case the first predetermined condition is met:  If the radio link control entity is an acknowledgment mode radio link control entity, stopping the discard timer, setting and starting a radio link control reset timer, and triggering the radio if the second predetermined condition is met Link control entity reset process;  If the radio link control entity is a radio link control entity in a non-acknowledgment mode or a radio link control entity in a transparent mode, discarding the service data unit;  The first predetermined condition is: before the drop timer expires, the PDCP SDU has been delivered to the radio link control layer and the radio link control sequence number has been allocated; the second predetermined condition is When the radio link control reset timer expires, there are radio link control protocol data units that are not successfully transmitted in all radio link control protocol data units involved in the PDCP SDU. The method of claim 9, wherein after the discarding timer is started, the method further includes:  If the third predetermined condition is met, the service data unit is discarded; wherein, the third predetermined condition is: when the discarding timer expires, the PDCP SDU has not been submitted to the radio link control layer; or When the discard timer expires, the PDCP SDU has been delivered to the radio link control layer, but the radio link control sequence number has not been allocated yet. The reset control method according to claim 9, wherein after the wireless link control reset timer is started, the method further includes:  Stopping the radio link control reset timer if the fourth predetermined condition is met;  The fourth predetermined condition is that all radio link control protocol data units involved in the PDCP SDU have been successfully sent before the radio link control reset timer expires.