WO2015120698A1

WO2015120698A1 - Method and device for reducing number of ue releases, and base station

Info

Publication number: WO2015120698A1
Application number: PCT/CN2014/083588
Authority: WO
Inventors: 李凤军
Original assignee: 中兴通讯股份有限公司
Priority date: 2014-02-17
Filing date: 2014-08-01
Publication date: 2015-08-20
Also published as: CN104853372A; CN104853372B

Abstract

Provided are a method and device for reducing the number of UE releases, and a base station. The method comprises: when a PDU reaches the maximum number of retransmissions, air interface resources and/or air interface quality conditions of a main carrier and an auxiliary carrier corresponding to the PDU satisfy a predetermined condition, deactivating the auxiliary carrier and allowing the PDU to be continuously retransmitted. By means of the technical solution provided in the present invention, the number of times that a UE is released by an RRC connection is reduced, and the probability of a UE being released by the RRC connection is reduced, thereby improving the performance of a communication system and improving the user experience.

Description

The present invention relates to the field of mobile communication systems, and more particularly to user equipment (UE, User in a carrier aggregation scenario in a Long Term Evolution Advanced (LTE-A) communication system. Equipment) is released. In a carrier aggregation (CA) in an LTE-A communication system, a base station can aggregate two or more component carriers (CCs) to provide services for the UE to support a larger Transmission bandwidth. The UE can receive or transmit data on one or more CCs simultaneously according to its capabilities.

When a UE in LTE-A establishes a Radio Resource Control (RRC) connection for the first time, only one serving cell, that is, a primary cell (PCell) is configured. The carrier in this serving cell is called a Primary Component Carrier (PCC) and is responsible for RRC communication with the UE. In the RRC reconfiguration process, one or more additional serving cells, that is, a secondary cell (SCell), are added to the UE according to factors such as load, quality of service (QoS), and the carrier in the serving cell is called auxiliary A component carrier (SCC) is used to provide additional radio resources. The PCell is always in an active state, and the UE only needs to perform downlink wireless link monitoring on the PCell. When the radio link fails, the RRC re-establishment process is triggered. Carrier aggregation is based on medium access control (MAC) aggregation. Each carrier has an independent hybrid automatic repeat request (HARQ) entity, and each transport block is mapped to only a single carrier. According to the description of the relevant protocol, when the radio link control (RLC) layer data is retransmitted to the maximum number of times, the radio link is considered to have failed. For the UE, if the access layer (AS, Access Stratum) security is not activated, the UE will leave the RRC connection state. If the AS security has activated the UE, the RRC connection re-establishment will be initiated. For the base station, the UE will be released. In a CA scenario, multiple carriers provide radio resources for the same UE at the same time. Since carrier aggregation is implemented at the MAC layer, the RLC layer does not see which carrier is sent in the MAC layer. When the data is retransmitted to the maximum number of times in the RLC layer, The UE will be released by the RRC connection. If the UE is released by the RRC connection too many times and the probability is too large, the user experience will be affected. SUMMARY OF THE INVENTION The present invention is directed to an improvement in the above problems in a communication system, that is, a technical problem to be solved by the present invention is to provide a method, apparatus, and base station for reducing the number of UE releases, which method, device, or base station can effectively reduce UE The number of RRC connection releases reduces the probability that the UE is released by the RRC connection. In order to solve the above technical problem, the method for reducing the number of UE release times provided by the embodiment of the present invention includes: when a protocol data unit (PDU) is the maximum number of retransmissions, and the primary carrier corresponding to the PDU And when the air interface resource and/or air interface quality condition of the secondary carrier satisfies a predetermined condition, the secondary carrier is deactivated, and the PDU is allowed to continue to be retransmitted. Preferably, the air interface resource and/or the air interface quality of the primary carrier and the secondary carrier meet the predetermined condition, including: the number of retransmissions of the PDU on the primary carrier and the number of retransmissions on the secondary carrier satisfy a predetermined condition; and Or the air interface quality coefficient of the primary carrier and the air interface quality coefficient of the secondary carrier satisfy a predetermined condition. Preferably, the number of retransmissions of the PDU on the primary carrier and the number of retransmissions on the secondary carrier satisfy a predetermined condition, including: a ratio of the number of retransmissions of the PDU on the primary carrier to the number of retransmissions on the secondary carrier is less than And the ratio of the air interface quality coefficient of the primary carrier to the air interface quality coefficient of the secondary carrier is greater than a predetermined threshold TH2. Preferably, the air interface quality coefficient is determined according to a BLOCK ERROR RATE (BLER) and a Channel Quality Indicator (CQI). Preferably, the PDU is allowed to continue to be retransmitted to allow the PDU to continue to be retransmitted N times, where N is a preset positive integer. The embodiment of the present invention further provides an apparatus for reducing the number of times of release of the user equipment UE, including: a statistics module and an air interface resource processing module; and a detection module and/or an air interface quality detection module; the statistics module is configured to determine a protocol data unit. Whether the PDU reaches the maximum number of retransmissions, and notifies the air interface resource detecting module and/or the air interface quality processing module when determining that the maximum number of retransmissions is reached; the air interface resource detecting module is configured to detect the air interface resources of the primary carrier and the secondary carrier, and Notifying the processing module when the detection result satisfies the predetermined condition; and/or the air interface quality detecting module is configured to detect the air interface quality of the primary carrier and the secondary carrier, and notify the processing module when the detection result satisfies the predetermined condition; the processing module, setting To deactivate the secondary carrier, the notification statistics module is allowed to continue the retransmission of the PDU. Preferably, the air interface resource detecting module is specifically configured to determine whether the number of retransmissions of the PDU on the primary carrier and the number of retransmissions on the secondary carrier meet predetermined conditions, and notify the processing module when the predetermined condition is met; the air interface quality detecting module Specifically, it is configured to detect a quality coefficient of the primary carrier and a quality coefficient of the secondary carrier corresponding to the PDU, and notify the processing module when the air interface quality coefficient of the primary carrier corresponding to the PDU and the air interface quality coefficient of the secondary carrier satisfy a predetermined condition. Preferably, when the ratio of the number of retransmissions of the PDU on the primary carrier to the number of retransmissions on the secondary carrier is less than a predetermined value TH1, the processing module is notified; when the air interface quality coefficient of the primary carrier corresponding to the PDU and the secondary When the ratio of the air interface quality coefficient of the carrier is greater than the predetermined value TH2, the processing module is notified. Preferably, the air interface quality coefficient is determined according to the air interface block error rate BLER and the channel quality indicator CQI. The embodiment of the present invention further provides a base station, including the foregoing apparatus for reducing the number of times the UE of the user equipment is released. When the maximum number of retransmissions of a protocol data unit (PDU) of the RLC layer is reached by using the method, the device, or the base station provided by the present invention, if the air interface resource and/or the air interface quality of the primary carrier and the secondary carrier are determined to be satisfied The predetermined condition; then the secondary carrier is deactivated and the PDU is allowed to continue to retransmit. This reduces the number of times the UE is released by the RRC connection, reduces the probability of the UE being released by the RRC connection, thereby improving the performance of the communication system and improving the user experience. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flow chart showing the basic steps of a method for reducing the number of UEs released in the embodiment of the present invention; FIG. 2 is a schematic diagram of Embodiment 1 of the present invention; FIG. 3 is a schematic diagram of Embodiment 2 of the present invention; FIG. 5 is a schematic diagram of a first implementation manner of the apparatus for reducing the number of UE releases according to the present invention; FIG. 6 is a schematic diagram of a second implementation manner of the apparatus for reducing the number of UE release times according to the present invention; A schematic diagram of a third implementation of the number of releases. 1 is a flowchart of a basic method for reducing the number of UE release times according to an embodiment of the present invention. As shown in the figure, the basic steps of the method for reducing the number of UE release times in the embodiment of the present invention include: Step 101: The base station determines that a PDU reaches the maximum. Step 102: The base station determines that the air interface resource and/or the air interface quality of the primary carrier and the secondary carrier corresponding to the PDU meet the predetermined condition; Step 103: The base station deactivates the secondary carrier, and allows the PDU to continue to retransmit. The air interface resources of the primary carrier and the secondary carrier satisfy the predetermined condition, including the air interface bandwidth of the primary carrier is smaller, and the air interface resource of the secondary carrier is more abundant; the air interface quality of the primary carrier and the secondary carrier meets predetermined conditions, including the quality of the primary carrier air interface is good. The secondary carrier air interface is of poor quality. Deactivating the secondary carrier, allowing the PDU to continue to retransmit, instead of directly following the RRC connection release procedure, can ensure that the primary carrier can continue to serve the UE, that is, the UE is still in the RRC connected state, reducing the dropped call rate of the UE, and improving user experience. If the PDU still reaches the maximum number of retransmissions when there is only the primary carrier service, the UE is released. In the embodiment of the present invention, the number of the primary and secondary carrier air interface resources may be determined according to the air interface scheduling of the primary carrier and the secondary carrier, that is, the number of retransmissions of the PDU on the primary carrier and the secondary carrier; More lenient, on the contrary, it means that the air interface resources are relatively tight. The air interface quality of the primary carrier and the secondary carrier can be determined by the air interface block error rate BLER, CQI and other indicators. The specific implementation method is explained in detail in the following specific embodiments. Embodiment 1 FIG. 2 is a schematic diagram of Embodiment 1 of the present invention. As shown in FIG. 2, the method for reducing the number of UE release times in this embodiment includes the following steps: Step 201: The base station RLC layer records the number of retransmissions of each PDU on its primary carrier and all secondary carriers; Step 202: The RLC layer determines Whether the PDU reaches the maximum number of retransmissions. If the PDU reaches the maximum number of retransmissions (set PDU1 to reach the maximum number of retransmissions), go to step 203; otherwise, the current flow ends; Step 203: The RLC layer determines that PDU1 is on its primary carrier. The ratio of the number of retransmissions to the number of retransmissions on each secondary carrier; for convenience of description, the ratio of the number of retransmissions of PDU1 on its primary carrier and secondary carrier X is Rx, ie, Rx=N_pcc/N_sccx, where N_pcc, N_sccx Representing the number of retransmissions of PDU1 on the primary carrier and on the secondary carrier X, respectively; Step 204: The RLC layer determines whether Rx is less than a predetermined threshold TH1. If yes, indicating that the air interface resource of the primary carrier is relatively abundant, and the primary carrier can continue to provide services for the UE, notify the MAC layer and jump to step 205. Otherwise, jump Step 207: The TH1 may be scheduled according to the requirements of the network to release the UE. In this embodiment, ΤΗ1=1/5; Step 205: The base station MAC layer initiates a secondary carrier deactivation process to deactivate the secondary carrier. X, and notify the RLC layer after completion; Step 206: The RLC layer allows PDU1 to continue retransmission, if the retransmission is successful, the current process ends; if it continues to retransmit after N times, then go to step 207; The number of times that the default is allowed to continue retransmission is a positive integer. Specifically, the RNLC can report the error indication according to the specific networking environment, and the RNLC receives the error indication after receiving the error indication. The RRC connection release command is issued, and the UE is released. Embodiment 2 FIG. 3 is a schematic diagram of Embodiment 2 of the present invention. As shown in FIG. 3, the method for reducing the number of UE release times in this embodiment includes the following steps: Step 301: The base station MAC layer detects the air interface quality of all activated carriers of the UE in a period of time, and according to the air interface quality coefficient. = CQI/BLER gives the air interface quality factor of each carrier. Step 302: The base station RLC layer records the number of retransmissions of each PDU on its primary carrier and all secondary carriers. Step 303: The RLC layer determines whether one PDU reaches the maximum number of retransmissions, and if one PDU reaches the maximum number of retransmissions ( If the PDU2 reaches the maximum number of retransmissions, the MAC layer is notified and the process proceeds to step 304; otherwise, the current process is terminated; Step 304: The base station MAC layer determines the air interface quality coefficient of the primary carrier corresponding to the PDU2 and the air interface quality of each secondary carrier. For the convenience of description, the ratio of the air interface quality coefficient of the primary carrier and the secondary carrier X corresponding to PDU2 is Qx, that is, Qx=C_pcc/C_sccx, where: C_pcc, C_pccx represent the air interface of the primary carrier and the secondary carrier X, respectively. Quality factor Step 305: Determine whether Qx is greater than a predetermined threshold TH2. If yes, it indicates that the air interface quality of the primary carrier is good, and the quality of the secondary carrier X air interface is poor. The primary carrier may continue to provide services for the UE, and the process proceeds to step 306. If the Qx is less than the predetermined threshold TH2, the process proceeds to step 308. The TH2 may be scheduled according to the requirement of the network release rate of the UE. In this embodiment, It can take TH2=5; Step 306: The MAC layer initiates a secondary carrier deactivation procedure, deactivates the secondary carrier X, and notifies after completion

RLC layer; Step 307: The RLC layer allows the PDU2 to continue retransmission. If the retransmission is successful, the current process is ended. If the retransmission continues after the N times, the process proceeds to step 308; where N is the preset permission to continue to be heavy. The number of times of transmission: Step 308: The RLC layer reports an error indication to the RNLC, and after receiving the error indication, the RNLC sends an RRC connection release command to release the UE. Embodiment 3 FIG. 4 is a schematic diagram of Embodiment 3 of the present invention. As shown in FIG. 4, the method for reducing the number of UE release times in this embodiment includes the following steps: Step 401: The MAC layer of the base station detects the air interface quality of all activated carriers of the UE in a period of time, and obtains the air interface quality coefficient C=CQI/BLER according to the air interface quality coefficient C=CQI/BLER The air interface quality coefficient of each carrier is generated; Step 402: The RLC layer of the base station records the number of retransmissions of each PDU on its primary carrier and all the secondary carriers; Step 403: The RLC layer determines whether one PDU reaches the maximum number of retransmissions, if any One PDU reaches the maximum number of retransmissions (set PDU3 to reach the maximum number of retransmissions), and jumps to step 404; otherwise, the current flow ends; Step 404: The RLC layer determines the number of retransmissions of PDU3 on its primary carrier and on each secondary carrier. The ratio of the number of retransmissions on the PDU3 is the ratio Rx of the number of retransmissions on the primary carrier and the number of retransmissions on the secondary carrier X, that is, Rx=N_pcc/N_sccx, where N_pcc and N_sccx respectively represent the PDU3 in the primary carrier and the secondary The number of retransmissions on the carrier X; Step 405: The RLC layer determines whether Rx is less than the predetermined threshold TH1; if yes, notifies the MAC layer to jump to step 406, otherwise, notifies the MAC layer and jumps to step 41 0; in this embodiment, ΤΗ1=1/5 can be taken; Step 406: The MAC layer determines a ratio of an air interface quality coefficient of the primary carrier corresponding to the PDU3 and a quality coefficient of each secondary carrier air interface. The ratio of the air interface quality coefficient of the primary carrier corresponding to the PDU3 and the air interface quality coefficient of the secondary carrier X is Qx. That is, Qx=C_pcc/C_sccx, where: C_pcc, C_pccx represent the air interface quality coefficients of the primary carrier and the secondary carrier X, respectively; Step 407: The MAC layer determines whether Qx is greater than a predetermined threshold TH2, and if present, indicates that the primary carrier at this time The air interface quality is better, and the secondary carrier X air interface quality is worse; and the Rx is smaller than TH1, indicating that the primary carrier resources are relatively abundant; this means that the primary carrier can continue to provide services for the UE, the jump goes to step 408; if it does not exist If Qx is greater than the predetermined threshold TH2, go to step 410; in this embodiment, TH2=5 may be taken; Step 408: The MAC layer initiates a secondary carrier deactivation procedure, deactivates the secondary carrier X, and notifies after completion

RLC layer; Step 409: The RLC layer allows the PDU3 to continue to retransmit. If the retransmission is successful, the current process ends; if the retransmission continues after the N times, the process proceeds to step 410; where N is the preset permission to continue to be heavy. The number of times of transmission: Step 410: The RLC layer reports an error indication to the RNLC, and after receiving the error indication, the RNLC sends an RRC connection release command to release the UE. It should be understood that the technical solutions in the above embodiments may be used in combination without conflict. The RLC layer allows the PDU to continue retransmission by an error indication message that does not report the PDU to the control plane to the maximum number of retransmissions. 5, FIG. 6, and FIG. 7 are schematic diagrams of three implementations of an apparatus for reducing the number of UE release times according to an embodiment of the present invention. The first implementation manner is as shown in FIG. 5. The device includes a statistics module, an air interface resource detection module, and a processing module. The working mode is: the statistic module determines whether the protocol data unit PDU reaches the maximum number of retransmissions, and notifies the air interface resource detecting module when determining that a PDU (set to PDU4) reaches the maximum number of retransmissions; the air interface resource detecting module detects the PDU4 corresponding to the PDU4. The air interface resource of the primary carrier and the secondary carrier, and the processing module is notified when the detection result satisfies the predetermined condition; because the amount of the primary carrier and the secondary carrier air interface resource can be determined according to the scheduling frequency, the air interface resource detecting module can specifically determine the PDU4 Whether the number of retransmissions on the primary carrier and the number of retransmissions on the secondary carrier satisfy a predetermined condition, and notify the processing module when satisfied; the processing module receives the air interface resource After the notification sent by the detection module satisfies the predetermined condition, the secondary carrier is deactivated, and the statistic module is notified to allow the PDU to continue retransmission. Preferably, when the ratio of the number of retransmissions of the PDU on the primary carrier to the number of retransmissions on any one of the secondary carriers is less than the predetermined value TH1, the processing module is notified; the number of times the PDU is allowed to continue to be retransmitted may be based on the frequency of releasing the UE and The requirements for data transmission delay are preset. The TH1 can be scheduled according to the requirement of the network to release the frequency of the UE. In this embodiment, ΤΗ1=1/5 can be taken. The second implementation manner is shown in FIG. 6. The device includes a statistics module, an air interface quality detection module, and a processing module. The working mode is as follows: The statistics module determines whether the protocol data unit PDU reaches the maximum number of retransmissions, and notifies the air interface resource detecting module when determining that a certain PDU (set to PDU5) reaches the maximum number of retransmissions; the air interface quality detecting module detects the corresponding PDU4 The air interface quality of the primary carrier and the secondary carrier, and notifying the processing module when the detection result satisfies the predetermined condition; specifically, detecting that the ratio of the air interface quality coefficient on the primary carrier corresponding to the PDU 5 and the air interface quality coefficient on the secondary carrier is satisfied Notifying the processing module when the condition is predetermined; after receiving the notification that the air interface quality detecting module sends the predetermined condition, the processing module deactivates the secondary carrier, and notifies the statistics module to allow the PDU to continue to retransmit. Preferably, when the ratio of the air interface quality coefficient of the PDU on the primary carrier to the air interface quality coefficient on any secondary carrier is greater than the predetermined value TH2, the processing module is notified, wherein the air interface quality coefficient may be determined according to the BLER and the CQI, and the specific air interface is determined. The quality coefficient is equal to the ratio of CQI to BLER, that is, the air interface quality coefficient is <:01/61^1 _. As in the first implementation manner, the number of times that the PDU is allowed to continue retransmission can be preset, and TH2 can release the frequency to the UE according to the network construction. The request is to be predetermined. In this embodiment, TH2=5 can be taken. The third implementation manner is shown in FIG. 7. The device includes a statistics module, an air interface resource detection module, an air interface quality detection module, and a processing module. The difference between the first implementation and the second implementation manner is that the processing module receives the notification that the air interface resource detection module sends the predetermined condition, and/or the air interface quality detection module sends the satisfaction request. After the conditional notification, the secondary carrier is deactivated, and the statistics module is notified to allow the PDU to continue to retransmit. In the device of the embodiment of the present invention, the statistic module and the air interface resource detecting module are located at the RLC layer of the base station, and the air interface quality detecting module and the processing module are located at the MAC layer of the base station. The base station provided by the embodiment of the present invention includes the apparatus for reducing the number of UE release times as described in any one of the foregoing three implementation manners. In the embodiment of the present invention, the maximum number of retransmissions of the PDU is: The number of times that the same PDU of the RLC layer is repeatedly transmitted on the air interface reaches the maximum number of retransmissions, where the maximum number of retransmissions is configured by the base station during the UE access process. In addition, the RLC does not receive the acknowledgement of the packet for a certain period of time after receiving the PDU or receives the NACK (Nacknowledge, no acknowledgement) of the packet, and then retransmits the packet. It is to be understood that various changes and substitutions may be made in accordance with the description of the invention and the embodiments of the invention. range.

Claims

The present invention provides a method for reducing the number of times a user equipment UE is released, including: when a protocol data unit PDU reaches a maximum number of retransmissions, and the air interface resource and/or air interface quality of the primary carrier and the secondary carrier corresponding to the PDU When the predetermined condition is met, the secondary carrier is deactivated and the PDU is allowed to continue to be retransmitted. The method according to claim 1, wherein the air interface resource and/or air interface quality of the primary carrier and the secondary carrier meet predetermined conditions, including:

The number of retransmissions of the PDU on the primary carrier and the number of retransmissions on the secondary carrier satisfy a predetermined condition; and the air interface quality coefficient of the primary carrier and the air interface quality coefficient of the secondary carrier satisfy a predetermined condition. The method according to claim 2, wherein the number of retransmissions of the PDU on the primary carrier and the number of retransmissions on the secondary carrier satisfy a predetermined condition, including: the number of retransmissions of the PDU on the primary carrier and The ratio of the number of retransmissions on the secondary carrier is less than a predetermined threshold TH1; the air interface quality coefficient of the primary carrier and the quality coefficient of the secondary carrier satisfy a predetermined condition, including: an air interface quality coefficient of the primary carrier and the secondary carrier The ratio of the air quality coefficient is greater than a predetermined threshold

The method according to claim 2 or 3, wherein the air interface quality coefficient is determined according to an air interface block error rate BLER and a channel quality indicator CQI. The method according to claim 1, wherein the allowing the PDU to continue to retransmit to allow the PDU to continue to be retransmitted N times, where N is a preset positive integer. And a device for reducing the number of UE device release times, comprising: a statistics module and a processing module; and further comprising an air interface resource detection module and/or an air interface quality detection module;

The statistic module is configured to determine whether the protocol data unit PDU reaches the maximum number of retransmissions, and notify the air interface resource detecting module and/or the air interface quality detecting module when determining that the maximum number of retransmissions is reached; the air interface resource detecting module is set to Detecting air interface resources of the primary carrier and the secondary carrier, and notifying the processing module when the detection result satisfies a predetermined condition; and/or

The air interface quality detecting module is configured to detect air interface quality of the primary carrier and the secondary carrier, and notify the processing module when the detection result satisfies a predetermined condition; The processing module is configured to deactivate the secondary carrier and notify the statistics module to allow the PDU to continue to retransmit. The apparatus according to claim 6, wherein the air interface resource detecting module is configured to determine whether the number of retransmissions of the PDU on the primary carrier and the number of retransmissions on the secondary carrier satisfy a predetermined condition, and satisfy the predetermined condition Notifying the processing module when conditions are met;

The air interface quality detecting module is configured to detect a quality coefficient of a primary carrier corresponding to the PDU and a quality coefficient of a secondary carrier, and satisfy a predetermined condition in an air interface quality coefficient of the primary carrier corresponding to the PDU and an air interface quality coefficient of the secondary carrier. Notify the processing module. The apparatus according to claim 7, wherein when the ratio of the number of retransmissions of the PDU on the primary carrier to the number of retransmissions on the secondary carrier is less than a predetermined value TH1, the processing module is notified; when corresponding to the PDU When the ratio of the air interface quality coefficient of the primary carrier to the air interface quality coefficient of the secondary carrier is greater than the predetermined value TH2, the processing module is notified. The apparatus according to any one of claims 6 to 8, wherein the air interface quality coefficient is determined according to an air interface block error rate BLER and a channel quality indicator CQI. A base station, comprising the apparatus for reducing the number of UE device release times according to any one of claims 6 to 9.