CN107302770A - A data retransmission method and device - Google Patents

Abstract

Disclosed herein is a data retransmission method, including: the upper layer protocol entity receives an indication that a first radio carrier currently used for transmitting the data packet is temporarily unavailable, or indicates that the User Equipment (UE) is accessed to a target node, or indicates a request for a status report; the upper layer protocol entity generates a state report according to the state of the buffer and sends the state report to an opposite end protocol entity through a second wireless carrier; and the upper layer protocol entity receives the data packet retransmitted by the opposite end protocol entity. The data retransmission method and the data retransmission device disclosed by the invention can reduce the loss of the bottom layer data packet as much as possible and realize the quick retransmission of the data packet in the service link replacement process, thereby effectively avoiding the reduction of the transmission throughput of the data packet.

Description

A data retransmission method and device

technical field

The invention relates to the technical field of mobile communication, in particular to a data retransmission method and device.

Background technique

Today, as 4G (the fourth Generation) communication networks are increasingly deployed, 5G (the fifth Generation) communication network technology has also been put on the agenda. 5G network strives to achieve an order of magnitude increase in data capacity, transmission speed and other aspects compared with 4G network, and can be applied to various scenarios at a lower cost, support various architectures, and be compatible with various terminals. On the other hand, superior performance also means that the deployment of 5G networks will become more complicated.

Looking forward to the future, the radio access network (Radio Access Network, RAN) is within the coverage of the widely deployed macro base station (Macro eNB, MeNB) that has an S1 interface with the core network (Core Network, CN). Selective and targeted deployment of low-power small cell nodes (Small eNB, SeNB) is an implementation strategy generally adopted by communication operators. In a 5G network, the SeNB may be able to support multiple frequency radio carriers (Carrier) and/or multiple radio access technologies (Radio Access Technology, RAT), or establish There are high-performance interfaces (such as the ideal interface (ideal backhaul)).

When the signal quality of the serving link of the source SeNB degrades, or when the resource load of the serving link of the source SeNB is too heavy, it is necessary to replace the serving link of the source SeNB or replace the SeNB. In order to meet the performance requirements of providing high-quality services for UEs, the 5G network hopes that during the service link replacement process, the user experience can be as imperceptible as possible, that is, the data throughput will not be greatly reduced. Therefore, how to minimize the loss of the underlying data packets and realize the fast retransmission of the data packets during the service link replacement process is a problem to be solved.

Because the transmission power is low, the wireless signal coverage of the small cell node will be much smaller than that of the macro base station. In addition, because the deployment environment of the communication network is becoming more and more complex, such as the existence of various obstructions on the communication path and the rapid movement of the user equipment, etc., it will cause frequent fluctuations in the signal quality of the wireless interface between the serving base station and the user equipment, resulting in more Frequent transmission link changes and/or service node switching.

In the prior art, there are basically two levels in the wireless protocol stack corresponding to the signal quality measurement of the wireless interface, corresponding resource allocation and mobility decision:

One is the bottom layer (mainly the physical layer (Physical layer, PHY), but it will affect the data transmission part of the media access control layer (Medium Access Control, MAC) entity, such as the Hybrid Automatic Repeat Request (Hybrid Automatic Repeat Request, HARQ (HARQ) entity) transmission link-related measurement, which requires a very short execution time, so it is very sensitive to the signal quality of the transmission link. In the prior art, such relatively instantaneous signal quality fluctuations basically have no explicit impact on upper layer protocol entities (such as radio link control (Radio Link Control, RLC) entities).

The other is the radio interface signal quality obtained by high-level layers (mainly referring to Radio Resource Control (RRC) entities) through the interaction of measurement configuration and reported control plane signaling. This measurement requires a long execution time and reflects is the average signal quality of the radio interface over a period of time. According to this measurement result, the access network node configured with the RRC entity can make a mobility handover decision (such as changing at least one serving base station of the UE), and during the execution of the handover procedure, the RLC entity and the following sublayers The context and data packets of the UE will be cleared, that is to say, after the UE accesses the new serving base station (target base station), the bearer data packets affected by the handover are at most within the data packet convergence protocol (Packet Data Convergence Protocol, PDCP ) sublayer for retransmission.

In the prior art, when the RLC entity carrying the data is configured as Acknowledged Mode (AM), this AM RLC entity has an Automatic Repeat Request (ARQ) function, which can support error-free data transmission. Specifically, this error-free data transmission is performed by the polling function of the active request status report (Status Report) of the sender of the data packet, the retransmission/re-segmentation function of the data packet, and the reception of the data packet. The status report sending function of the terminal is realized. However, on the one hand, it takes a certain amount of time for the data packet receiving end to detect the failure of data packet reception, which is related to the HARQ delay in the underlying MAC entity; on the other hand, the sending frequency of the status report needs to take into account the sending delay and The balance between wireless efficiency, therefore, AM RLC also has a function of status prohibition, to avoid sending status reports too frequently. It can be seen that when there is a problem with the quality of the underlying link, the RLC entity at the upper layer will not immediately respond to retransmission, but needs a certain waiting time, and correspondingly, during this period, AM RLC There will be more and more data packets (RLC Protocol Data Unit (Protocol Data Unit, PDU)) accumulated in the retransmission buffer of the entity.

In addition, when the serving base station node responsible for the bearer transmission of a certain data of the user equipment (User Equipment, UE) is changed, regardless of the sending end or the receiving end of the data, the data in the RLC entity and the following sublayers that have not been submitted to the upper layer protocol entity Both the package and the associated context are cleared. According to the user plane data packet forwarding mechanism and the notification scheme of control plane data transmission status information in the prior art, what the source base station transmits to the target base station is the status of the PDCP entity when the serving base station node changes/handovers. That is to say, in the process of changing the serving base station node, the data packet retransmission is implemented in the higher level of the wireless protocol stack - PDCP sublayer, and the higher the level of the encapsulation processing protocol involved in the data packet, the relatively required processing The time will be longer.

Among the underlying design goals of the 5G network, the use of new carrier frequency bands (such as high-frequency millimeter wave millimeter Wave, mmW) and codec processing solutions all have a common purpose, that is, to speed up the underlying transmission rate by orders of magnitude. Therefore, when the above-mentioned underlying transmission link needs to be changed or the serving base station node needs to be switched, according to the existing processing mechanism, the transmission throughput of the data packet will be reduced or even dropped significantly during this process. This has a very bad impact on the user experience.

Contents of the invention

In order to solve the above technical problems, the present invention provides a data retransmission method and device, which can minimize the loss of underlying data packets and realize fast retransmission of data packets in the process of service link replacement, thereby effectively avoiding data packet transmission. Throughput drops.

In order to achieve the purpose of the present invention, the present invention provides a data retransmission method, including:

The upper layer protocol entity receives the indication, the indication indicates that the first wireless carrier currently used to transmit the data packet is temporarily unavailable, or indicates that the user equipment UE is connected to the target node, or indicates a request for a status report;

The upper layer protocol entity generates a status report according to the status of the buffer, and sends the status report to the peer protocol entity through the second wireless carrier;

The upper layer protocol entity receives the data packet retransmitted by the peer protocol entity.

Wherein, the upper layer protocol entity receives an indication that the first wireless carrier currently used to transmit data packets is temporarily unavailable, including:

The upper layer protocol entity receives the indication sent by the lower layer protocol entity in the node where the indication indicates that the first wireless carrier currently used to transmit the data packet is temporarily unavailable;

The second wireless carrier is the wireless carrier used by the UE and the source serving node after stopping the transmission of the first wireless carrier.

Wherein, the method also includes:

The indication is sent by the underlying protocol entity in the node when it detects that the signal quality of the first wireless carrier drops to a preset threshold or is completely interrupted.

Wherein, the upper layer protocol entity receives an indication, and the indication indicates that the UE accesses the target node, including:

The upper layer protocol entity receives the indication sent by the lower layer protocol entity in the node where the indication indicates that the UE has accessed the target node;

The second wireless carrier is a wireless carrier used between the UE and the target node.

Wherein, before the upper layer protocol entity receives the indication, the method further includes:

The upper-layer protocol entity of the source serving node of the UE forwards the data packet and its serial number information in the buffer to the upper-layer protocol entity located at the target node;

The upper-layer protocol entity corresponding to the source serving node in the UE forwards the data packet and its serial number information in the buffer to the upper-layer protocol entity corresponding to the target node in the UE.

Wherein, when the upper-layer protocol entity is located in the UE, the upper-layer protocol entity refers to an upper-layer protocol entity corresponding to the source serving node in the UE, or an upper-layer protocol entity corresponding to the target node.

Wherein, the upper layer protocol entity receives the indication, the indication indicates a request for a status report, including: the upper layer protocol entity receives the indication on the second wireless carrier, and the indication is a polling request for a status report;

The second wireless carrier is the wireless carrier used by the UE and the source serving node after stopping the transmission of the first wireless carrier, or the wireless carrier used between the UE and the target node. 8. The method according to claim 1, further comprising: the upper layer protocol entity sorting and merging the data packets in the buffer and the received retransmission data packets.

Wherein, the upper layer protocol entity is the protocol entity above the MAC entity in the data packet receiving node on the wireless interface; the opposite end protocol entity is the data packet sending node on the wireless interface and the The upper layer protocol entity is a protocol entity at the same protocol stack level; the lower layer protocol entity is a physical layer PHY entity or the MAC entity.

The present invention also provides another data retransmission method, which includes: the peer protocol entity receives the status report sent by the upper layer protocol entity through the second wireless carrier, and the status report is sent by the upper layer protocol entity according to the status of the buffer after receiving the instruction. State generation, the indication indicates that the first wireless carrier currently used to transmit data packets is temporarily unavailable, or indicates that the user equipment UE has accessed the target node, or indicates a request for a status report; the peer protocol entity sends the The upper layer protocol entity retransmits the data packet.

Wherein, before the peer protocol entity receives the status report sent by the upper layer protocol entity through the second wireless carrier, it also includes: the peer protocol entity receives a message sent by the bottom layer protocol entity in the node where the message is currently used for transmission The first wireless carrier of the data packet is temporarily unavailable, or the UE is connected to the target node; the peer protocol entity sends a polling request to the upper layer protocol entity through the second wireless carrier, requesting the upper layer protocol entity to feedback a status report ; The second wireless carrier is the wireless carrier used by the UE and the source serving node after stopping the transmission of the first wireless carrier, or the wireless carrier used between the UE and the target node.

Wherein, the peer protocol entity retransmits the data packet to the upper layer protocol entity, comprising: the peer protocol entity retransmits the data packet on the second wireless carrier according to the information in the status report.

Wherein, the method further includes: detecting that the signal quality of the first wireless carrier recovers after a preset period of time, and the first wireless carrier is superior to the second wireless carrier in terms of transmission rate or resource load, Then, after completing the retransmission of the data packet, the peer protocol entity transfers the data packet back to the underlying protocol entity corresponding to the first wireless carrier for transmission.

The present invention also provides a data retransmission device, including: an indication module, a status report module, and a data packet receiving module; wherein, the indication module is used to receive an indication, and the indication indicates that the first wireless network currently used to transmit data packets The carrier is temporarily unavailable, or indicates that the user equipment UE is connected to the target node, or indicates a request for a status report; the status report module is configured to generate a status report according to the status of the buffer, and pass the status report through the second wireless carrier Send to the peer protocol entity; the data packet receiving module is used to receive the data packet retransmitted by the peer protocol entity; the data retransmission device is deployed in the upper layer protocol entity.

Wherein, the indication module is configured to receive the indication sent by the underlying protocol entity in the node where the indication indicates that the first wireless carrier currently used to transmit data packets is temporarily unavailable; the second wireless carrier is the The wireless carrier used by the UE and the source serving node after stopping the transmission of the first wireless carrier.

Wherein, the indication is sent by the underlying protocol entity in the node when it detects that the signal quality of the first wireless carrier drops to a preset threshold or is completely interrupted.

Wherein, the indication module is configured to receive the indication sent by the underlying protocol entity in the node, the indication indicates that the UE accesses the target node; the second wireless carrier is the link between the UE and the target node The wireless carrier used.

Wherein, the status reporting module is further configured to receive the data packet and its serial number information in the buffer forwarded by the upper-layer protocol entity of the source serving node of the UE or the upper-layer protocol entity of the corresponding source serving node in the UE.

Wherein, the upper layer protocol entity deploying the data retransmission device refers to the upper layer protocol entity corresponding to the source serving node in the UE, or the upper layer protocol entity corresponding to the target node.

Wherein, the indication module is configured to receive an indication on the second wireless carrier, and the indication is a polling request for a status report; the second wireless carrier is where the UE and the source serving node stop The wireless carrier used after the transmission of the first wireless carrier, or the wireless carrier used between the UE and the target node.

Wherein, the data packet receiving module is further configured to sort and merge the data packets in the buffer and the received retransmission data packets.

Wherein, the upper layer protocol entity deploying the data retransmission device is a protocol entity above the medium access control layer MAC entity in the data packet receiving node on the wireless interface; the peer protocol entity is the protocol entity on the wireless interface A protocol entity at the same protocol stack level as the upper protocol entity in the data packet sending node; the underlying protocol entity is a physical layer PHY entity or the MAC entity.

The present invention also provides a data retransmission device, including: a receiving module and a retransmission module; wherein, the receiving module is used to receive a status report sent by an upper-layer protocol entity through a second wireless carrier, and the status report is sent by the upper-layer protocol The entity generates according to the status of the buffer after receiving the indication, the indication indicates that the first wireless carrier currently used to transmit the data packet is temporarily unavailable, or indicates that the user equipment UE is connected to the target node, or indicates a request for a status report; The retransmission module is configured to retransmit data packets to the upper layer protocol entity; the data retransmission device is deployed on the peer protocol entity of the upper layer protocol entity.

Wherein, the receiving module is further configured to receive a message sent by the underlying protocol entity in the node where the peer protocol entity is located, and the message indicates that the first wireless carrier currently used to transmit data packets is temporarily unavailable, or that the UE receives into the target node; the device also includes: a sending module, configured to send a polling request to the upper layer protocol entity through the second wireless carrier, requesting the upper layer protocol entity to feed back a status report; the second wireless carrier It is the wireless carrier used by the UE and the source serving node after stopping the transmission of the first wireless carrier, or the wireless carrier used between the UE and the target node.

Wherein, the retransmission module is configured to retransmit the data packet on the second wireless carrier according to the information in the status report.

Wherein, the retransmission module is further configured to detect that the signal quality of the first wireless carrier recovers after a preset period of time, and that the first wireless carrier is superior to the second wireless carrier in terms of transmission rate or resource load. The wireless carrier, after completing the retransmission of the data packet, transfers the data packet back to the underlying protocol entity corresponding to the first wireless carrier for transmission.

Compared with the prior art, the embodiment of the present invention can immediately notify the upper-layer protocol entity when a wireless carrier signal quality degradation or complete interruption is detected, and the upper-layer protocol entity generates a status report and sends it through another wireless carrier at the earliest sending opportunity to the peer entity; or, the upper layer protocol entity requests the peer entity to feedback the status. Or, after the UE accesses the target SeNB, the RLC entity corresponding to the source SeNB or the RLC entity corresponding to the target SeNB sends a status report to the RLC entity in the target SeNB. In this way, it is possible to minimize the loss of underlying data packets and realize fast retransmission of data packets in the process of service link replacement, thereby avoiding the decrease of data packet transmission throughput, improving the rate of data packet transmission, and making the transmission and reception of data transmission Nodes can effectively manage protocol entity buffers, so as to bring users a communication experience that fully meets their needs.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Description of drawings

The accompanying drawings are used to provide a further understanding of the technical solution of the present invention, and constitute a part of the description, and are used together with the embodiments of the application to explain the technical solution of the present invention, and do not constitute a limitation to the technical solution of the present invention.

FIG. 1a is a schematic diagram of a communication system architecture applicable to an embodiment of the present invention;

FIG. 1b is a schematic diagram of another communication system architecture applicable to the embodiment of the present invention;

FIG. 2a is a schematic diagram of a user plane wireless protocol stack mode according to Embodiment 1 of the present invention;

FIG. 2b is a schematic diagram of another user plane wireless protocol stack mode according to an embodiment of the present invention;

FIG. 2c is a schematic diagram of another user plane wireless protocol stack mode according to an embodiment of the present invention;

FIG. 3 is a schematic flowchart of a data retransmission method according to an embodiment of the present invention;

FIG. 4 is a schematic flowchart of a data retransmission method in a preferred embodiment of the present invention;

FIG. 5 is a schematic flowchart of a data retransmission method in another preferred embodiment of the present invention;

FIG. 6 is a schematic flowchart of a data retransmission method in another preferred embodiment of the present invention;

7 is a schematic diagram of the composition and structure of a data retransmission device according to Embodiment 1 of the present invention;

FIG. 8 is a schematic diagram of the composition and structure of another data retransmission device according to an embodiment of the present invention.

detailed description

In order to make the purpose, technical solution and advantages of the present invention more clear, the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined arbitrarily with each other.

The steps shown in the flowcharts of the figures may be performed in a computer system, such as a set of computer-executable instructions. Also, although a logical order is shown in the flowcharts, in some cases the steps shown or described may be performed in an order different from that shown or described herein.

Fig. 1a and Fig. 1b are schematic diagrams of the system architecture of the communication system applicable to the embodiment of the present invention.

As shown in Figure 1a, SeNB-1 in RAN can support carriers of different frequency points, SeNB-2 and SeNB-3 support different RATs, and the two nodes are connected by ideal backhaul; SeNB and the serving gateway (Serving Gateway) in CN , S-GW) whether to establish an S1-U interface is optional, but an X2 interface is usually established between the SeNB and the MeNB. On the other hand, a UE with multiple Rx/Tx is in a Dual Connectivity (DC) or Multiple Connectivity (MC) state. In other words, the UE first accesses the MeNB, and the UE and the MeNB The wireless interface of the UE can at least transmit control plane signaling (that is, establish a radio resource control connection (RRC Connection)), and whether to establish a user plane data radio bearer (Data Radio Bearer, DRB) is optional; secondly, the UE communicates with at least one SeNB Establish a wireless interface, which can at least transmit user plane data. For example, after UE-1 accesses SeNB-1, it can obtain the data transmission service provided by SeNB-1. Specifically, SeNB-1 can decide to use Carrier- Carrier 1 and/or Carrier-2 communicate with UE, and UE-2 can obtain the data transmission service provided by SeNB-2 through RAT-1 after accessing SeNB-2.

As shown in Figure 1b, for two or more SeNBs within a certain range, a node (logical node) capable of centralized management of SeNBs within this specific range can also be deployed. In the embodiment of the present invention It is called the anchor point of the SeNB (SeNB Anchor). The ideal backhaul between the SeNB Anchor and the SeNB it manages may also be a non-ideal interface (non-ideal backhaul) with general performance, such as the X2 interface. From the perspective of the user plane, the SeNB Anchor establishes the S1-U interface with the S-GW, and SeNB-1 and SeNB-2, as the next-level nodes of the SeNB Anchor, only perform wired interface data transmission with the SeNB Anchor through the X2 interface . After the UE in DC state accesses MeNB, it can access SeNB-1 according to the instructions of MeNB, and obtain the data transmission service provided by SeNB-1 for UE through RAT-1; and after UE moves to the coverage of SeNB-2, The data transmission service provided by SeNB-2 through RAT-2 can be obtained by changing from SeNB-1 to SeNB-2 according to the instruction of the control plane signaling. Wherein, according to the capability of the UE, RAT-1/RAT-2 may be the same as or different from the RAT service provided by the MeNB for the UE.

FIG. 2a, FIG. 2b, and FIG. 2c are schematic diagrams of different wireless protocol stack formats applicable to embodiments of the present invention. In the wireless protocol stack mode shown in Figure 2a, the wireless protocol stack is only located in the MeNB, that is, the E-UTRAN radio access bearer (E-UTRAN Radio Access Bearer, E-RAB) that only uses MeNB resources can be called the primary cell group Bearer (Master Cell Group Bearer, MCG bearer), such as DRB-1; the wireless protocol stack is only located in SeNB, that is, E-RAB that only uses SeNB resources can be called Secondary Cell Group Bearer (SCG bearer), such as DRB-2. Taking SeNB-1 in Figure 1a as an example responsible for the transmission of DRB-2, according to UE capabilities, and/or signal quality of Carrier-1 and Carrier-2, and/or resource load conditions, SeNB-1 can decide Scheduling UE-1 on Carrier-1 or Carrier-2 for DRB-2 data transmission; corresponding to Carrier-1 and Carrier-2, PHY-1 and PHY-2 correspond to different HARQ entities in the MAC.

In the wireless protocol stack mode shown in Fig. 2b, the wireless protocol stack is located in the MeNB and the SeNB, that is, the bearer that uses resources of the MeNB and the SeNB at the same time may be called a split bearer, such as DRB-3. At the current moment, DRB-3 uses the resources of MeNB and SeNB-2, and MeNB serves as the anchor point of DRB-3 (with S1-U interface with S-GW) to establish a complete wireless protocol stack and SeNB corresponding to the DRB. -2 establishes the RLC entity and the following sublayers (namely MAC and PHY) for DRB-3, and what is transmitted on the X2 interface between MeNB and SeNB-2 is PDCP PDU.

In the wireless protocol stack mode shown in Figure 2c, UE is currently accessing MeNB and SeNB-1, SeNB Anchor serves as the anchor point of the user plane on the SeNB side, a PDCP entity configured with DRB, and SeNB-1 serves as the UE’s serving base station The RLC entity configured with DRB and the sublayers below, and the X2 interface between SeNB Anchor and SeNB-1 transmit PDCP PDUs.

Among them, the type of small cell nodes, the number of carriers that can be supported, the type and number of RATs that can be supported, whether to establish a wired interface with the core network, and the establishment of interfaces between small cell nodes and between small cell nodes and macro base stations Neither form nor kind is limited. On the other hand, there are no restrictions on the number of serving base stations and the type and number of serving carriers for multiple Rx/Tx UEs.

That is to say, all the embodiments of the present invention are applicable within the schematic frameworks of Fig. 1a, Fig. 1b, Fig. 2a, Fig. 2b, and Fig. 2c.

It should be noted that, hereinafter, the RLC entity of the sending node of the user plane radio bearer data packet is called RLC-1, and the RLC entity of the receiving node is called RLC-2. Wherein, for downlink data, the sending node is a node in the access network, such as SeNB; for uplink data, the sending node is UE. For downlink data, the receiving node is UE; for uplink data, the receiving node is a node in the access network, such as SeNB.

As shown in Figure 3, an embodiment of the present invention provides a data retransmission method, the method comprising:

Step 301: The upper layer protocol entity receives an indication, the indication indicates that the first wireless carrier currently used to transmit data packets is temporarily unavailable, or indicates that the user equipment UE has accessed the target node, or indicates a request for a status report;

Step 302: The upper layer protocol entity generates a status report according to the status of the buffer, and sends the status report to the peer protocol entity through the second wireless carrier;

Step 303: The upper layer protocol entity receives the data packet retransmitted by the peer protocol entity.

Specifically, the upper-layer protocol entity receives an indication that the first wireless carrier currently used to transmit data packets is temporarily unavailable, including: the upper-layer protocol entity receives the indication sent by the lower-level protocol entity in the node where it is located, and the The above indication indicates that the first wireless carrier currently used to transmit data packets is temporarily unavailable; the second wireless carrier is the wireless carrier used by the UE and the source serving node after stopping the transmission of the first wireless carrier. Here, the indication is sent by the underlying protocol entity in the node when it detects that the signal quality of the first wireless carrier drops to a preset threshold or is completely interrupted.

Specifically, the upper layer protocol entity receiving the indication, the indication indicating that the UE has accessed to the target node, includes: the upper layer protocol entity receiving the indication sent by the lower layer protocol entity in the node where the UE is located, the indication indicating that the UE has accessed to the target node A node; the second wireless carrier is a wireless carrier used between the UE and the target node. Further, before the upper layer protocol entity receives the indication, the method may further include: the upper layer protocol entity of the source serving node of the UE forwards the data packet and its number information in the buffer to the The upper-layer protocol entity of the node; the upper-layer protocol entity corresponding to the source serving node in the UE forwards the data packet and its serial number information in the buffer to the upper-layer protocol entity corresponding to the target node in the UE. Here, when the upper-layer protocol entity is located in the UE, the upper-layer protocol entity refers to an upper-layer protocol entity corresponding to the source serving node in the UE, or an upper-layer protocol entity corresponding to the target node.

Specifically, the upper layer protocol entity receiving an indication, the indication representing a request for a status report, includes: the upper layer protocol entity receives an indication on the second wireless carrier, and the indication is a polling request for a status report; The second wireless carrier is the wireless carrier used by the UE and the source serving node after stopping the transmission of the first wireless carrier, or the wireless carrier used between the UE and the target node.

After step 303, the method further includes: the upper layer protocol entity sorting and merging the data packets in the buffer and the received retransmission data packets.

Specifically, the upper layer protocol entity mentioned above may be a protocol entity above the MAC entity in the data packet receiving node on the wireless interface; the peer protocol entity may be the data packet sending node on the wireless interface and the The upper layer protocol entity is a protocol entity at the same protocol stack level; the lower layer protocol entity may be a physical layer PHY entity or the MAC entity.

Correspondingly, on the side of the peer protocol entity, an embodiment of the present invention also provides a data retransmission method, including: the peer protocol entity receives a status report sent by the upper layer protocol entity through the second wireless carrier, and the status report is sent by the The upper layer protocol entity generates according to the status of the buffer after receiving the indication, the indication indicates that the first wireless carrier currently used to transmit the data packet is temporarily unavailable, or indicates that the user equipment UE is connected to the target node, or indicates that the status report Request; the peer protocol entity retransmits the data packet to the upper layer protocol entity.

Wherein, before the peer protocol entity receives the status report sent by the upper layer protocol entity through the second wireless carrier, it may also include: the peer protocol entity receives a message sent by the bottom layer protocol entity in the node where the message is currently used The first wireless carrier for transmitting data packets is temporarily unavailable, or the UE accesses the target node; the peer protocol entity sends a polling request to the upper layer protocol entity through the second wireless carrier, requesting the upper layer protocol entity to feedback the status Reporting; the second wireless carrier is the wireless carrier used by the UE and the source serving node after stopping the transmission of the first wireless carrier, or the wireless carrier used between the UE and the target node.

Specifically, the retransmission of the data packet by the peer protocol entity to the upper layer protocol entity includes: the peer protocol entity retransmits the data packet on the second wireless carrier according to the information in the status report.

Wherein, it is detected that the signal quality of the first wireless carrier recovers after a preset period of time, and the transmission rate or resource load of the first wireless carrier is better than that of the second wireless carrier, then after completing the transmission of the data packet After retransmission, the peer protocol entity may also transfer the data packet back to the underlying protocol entity corresponding to the first wireless carrier for transmission.

The data retransmission method according to the embodiment of the present invention will be described in detail below for different scenarios.

Scenario 1: The serving base station (such as SeNB-1) accessed by the UE has two or more wireless carriers (such as Carrier-1 and Carrier-2, where Carrier-1/2 can be the same or different RAT), and the UE A data packet of a data bearer is currently transmitted through Carrier-1 and SeNB-1; or, SeNB-1 accessed by the UE has a wireless carrier Carrier-1, and SeNB-1 communicates with another base station node (SeNB-2 , Carrier-2) are connected, wherein, the frequencies of Carrier-1 and Carrier-2 are different, and the RATs can be the same or different, and SeNB-2 has the RLC entity corresponding to the UE and the data bearer and the configuration of the following sublayers /context. When there is a problem with the underlying transmission link of Carrier-1, the RLC PDU carried by the data can be retransmitted through Carrier-2 as necessary.

In Scenario 1, for the receiving node of the user plane data packet, when the underlying protocol entity (PHY and MAC entity, or at least the data transmission part in the existing MAC entity, such as the HARQ entity) detects that Carrier-1 When the signal quality drops to a certain threshold (eg, preset threshold) or even completely interrupted (eg, an obstruction appears in the mmW transmission path), the MAC entity immediately indicates the detection result to the upper layer protocol entity (eg, RLC-2). After the upper-layer protocol entity receives the indication of the detection result, it immediately checks the status of the data packet buffer to generate a status report, and sends it to the peer entity (the protocol entity of the data packet sending node, such as RLC-1). The peer entity retransmits the corresponding data packet on Carrier-2 according to the information indicated in the Status Report received.

In Scenario 1, for the sending node of the user plane data packet, when the underlying protocol entity detects that the signal quality of Carrier-1 has dropped to a certain threshold (such as a preset threshold) or even completely interrupted, the upper layer protocol entity (such as RLC -1) After knowing the detection result, immediately initiate a polling request (polling) to the peer entity (such as RLC-2 or UE), that is, request the peer to feed back a status report, wherein polling is sent through Carrier-2 . After receiving the polling request, the peer entity immediately generates a status report and sends it through Carrier-2. In Scenario 1, if the signal quality of Carrier-1 recovers after a short period of time (within the preset time period) (that is, the mobility decision of the RRC layer has not yet been caused), then if Carrier-1 is between the transmission rate and It is superior to Carrier-2 in terms of/or resource load, and data packets can be transferred back to the MAC/PHY entity corresponding to Carrier-1 for transmission. In this case, because the transmission status of Carrier-2 may still be good, whether to perform the sending process of the above status report can be decided by the receiving end entity. Wherein, the MAC entity of Carrier-1 can be made to submit an indication that Carrier-1 can be used to an upper layer protocol entity (such as RLC-1), or submit a transmission opportunity (transmission opportunity) of a schedulable RLC data packet to RLC-1, In this way, the sending node learns the information available to Carrier-1. Further, if Carrier-2 insists on sending the data packets scheduled for transmission to completion, then the protocol entity of the receiving node (such as RLC-2 or UE) needs to perform the function of merging and sorting.

Scenario 2: The UE transmits data packets of a certain bearer through Carrier-1 and SeNB-1, and the mobility decision determines that the bearer needs to be changed to SeNB-2 (Carrier-2) to continue transmission; The PDCP entity on the access side is located at the MeNB or SeNB Anchor, that is to say, the node will not be changed with the change of the SeNB.

In the process of changing the bearer serving node, taking the downlink data as an example, the protocol entity (such as the RLC entity) located on the MAC entity of the source SeNB will store the data packet in the buffer and the corresponding sequence number (Sequence Number, SN ) to the protocol entity located in the target SeNB; the RLC entity corresponding to the source SeNB in the UE forwards the data packet in the buffer to the RLC entity corresponding to the target SeNB. After the UE accesses the target SeNB, the RLC entity corresponding to the target SeNB in the UE sends a status report (Status Report) to the peer entity located in the target SeNB, that is, the RLC entity, and the RLC entity in the target SeNB according to the status report (Status Report) Make the necessary RLC packet retransmission according to the information indicated in . Wherein, if the RLC entity corresponding to the source SeNB has not cleared the data packet and context after the UE accesses the target SeNB, then the status report may also be sent by the RLC entity corresponding to the source SeNB in the UE to the peer entity located in the target SeNB. The RLC entity corresponding to the target SeNB in the UE will combine the data packets from the RLC entity corresponding to the source SeNB and the data packets from the RLC entity in the target SeNB for processing such as sorting.

It should be noted that the RLC entity and data packet are the titles of the wireless protocol entity and data packet in the E-UTRAN system in the embodiment of the present invention, and may actually refer to the protocol entity and data packet above the MAC entity in the user plane ( It may even be a data packet above the HARQ entity in the MAC entity), that is, other names will not affect the essence of the solution described in the embodiment of the present invention.

The specific implementation process of data retransmission in the embodiment of the present invention will be described in detail below in the form of specific embodiments for different scenarios.

Embodiment one

The schematic diagram of the system architecture in Figure 1a and the schematic diagram of the user plane wireless protocol stack mode in Figure 2a, this embodiment mainly uses UE-1 as an example to illustrate the specific implementation process of data retransmission in the present invention.

Specifically, the serving base stations currently accessed by UE-1 in the DC state are MeNB and SeNB-1, where MeNB has established a control plane RRC connection with UE-1, and transmits DRB with UE-1 on the user plane. -1 (MCG bearer) data packet; SeNB-1 and the S-GW in the core network have an S1-U interface, and the node itself is configured with Carrier-1 and Carrier-2 two carriers (which can be different frequencies of the same RAT) carrier, or the RATs of the two carriers are different), and SeNB-1 currently uses Carrier-1 to transmit data packets of DRB-2 (SCG bearer) with UE. Further, from the perspective of the wireless protocol stack, the difference between Carrier-1 and Carrier-2 is mainly reflected in different PHY layers (PHY-1 and PHY-2 have different parameter configurations), and SeNB-1 is Carrier-1 A unified MAC entity can be configured with Carrier-2 (in the MAC entity, corresponding to PHY-1 and PHY-2, there will be HARQ-1 and HARQ-2 entities), or two MAC entities can be configured separately; and for the upper layer protocol entity Speaking of (such as RLC and PDCP entities), there is only one corresponding to DRB-2.

Taking downlink data as an example, Figure 4 is a schematic diagram of the status report sending process of the SCG bearer data packet receiving node (UE-1), which mainly includes the following steps:

Step 401: The PHY/MAC entity starts to receive SCG bearer data on Carrier-1, the PHY performs the signal measurement of the wireless interface, and the PHY/MAC determines whether there is a blockage, and if so, the MAC of UE-1 The entity indicates to the upper layer protocol entity (such as the RLC entity) the information that Carrier-1 is temporarily unavailable and continues to step 302, otherwise continue to perform the signal measurement of the radio interface;

Specifically, during the transmission process of DRB-2 (SCG bearer), the PHY of UE-1 will measure the signal quality of the first radio link bearer (Carrier-1) chain in real time according to the configuration of SeNB-1, and the PHY layer And/or the MAC sublayer will judge the signal condition of the wireless link according to the measurement result and perform corresponding data packet scheduling. Taking Carrier-1 as a high-frequency carrier and a blockage appears in the transmission path as an example, the underlying protocol entity (PHY and/or MAC entity) of UE-1 knows that Carrier-1 cannot transmit data packets (or HARQ The transmission failure rate of the -1 entity is high), therefore, the MAC entity of UE-1 indicates to the upper layer protocol entity (such as the RLC entity) that Carrier-1 is temporarily unavailable, and changes the underlying transmission link to Carrier-2 ( PHY-2 and HARQ-2).

Step 402: As the receiving node of the data packet, after the RLC entity corresponding to DRB-2 in UE-1 receives the instruction submitted by the underlying entity (such as the MAC entity), it knows that the underlying transmission link of Carrier-1 has been interrupted (that is, the HARQ -1 entity cannot successfully complete the behavior of receiving the data packet), so the RLC entity (specifically, the receiving side in the AM RLC entity) checks the status in the current buffer and generates a status report, and carries it over the first radio link as early as possible (Carrier-2)C sends the status report to the peer entity (the RLC entity in SeNB-1).

Step 403: After receiving the status report, the RLC entity corresponding to DRB-2 in SeNB-1 performs corresponding data packet retransmission and necessary re-segmentation according to the information indicated therein, and combines the retransmitted data packet with the subsequent initial transmission The data packet is sent to UE-1 through Carrier-2.

Here, the RLC entity in UE-1 also jointly performs processing such as sorting and merging on the data packets in the buffer and the data packets received on Carrier-2.

It should be noted that if the signal quality of Carrier-1 recovers after a short period of time (that is, other influences such as the mobility decision of the RRC entity have not been triggered), then if Carrier-1 is in the transmission speed or resource load, etc. It is better than Carrier-2 in terms of data packets can be changed back to the MAC/PHY entity corresponding to Carrier-1 for transmission. In this case, because the transmission status of Carrier-2 may still be good (that is, the operation of changing back is not due to an obstruction in the transmission path of Carrier-2), so whether it is necessary to implement the solution described in this embodiment It can be decided by the RLC entity of UE-1 at its own discretion.

Embodiment two

Referring to the communication system architecture in FIG. 1a and the user plane wireless protocol stack mode in FIG. 2b, this embodiment mainly uses UE-2 as an example to illustrate the specific implementation process of data retransmission in the present invention.

Specifically, the serving base stations currently accessed by UE-2 in the DC state are MeNB and SeNB-2, wherein, a control plane RRC connection is established between MeNB and UE-2, and a complete DRB-3 is established on the user plane. Protocol stack, and transmit DRB-3 data packets with UE-2 through the wireless interface; SeNB-2 transmits DRB-3 data packets with UE-2 through the RAT-1 carrier supported by itself, wherein the DRB-3 It is a split bearer form in the existing DC user plane architecture. Further, SeNB-2 is connected to the adjacent node SeNB-3 (the wireless interface supports RAT-2 carrier) through ideal backhaul, and there is an X2 interface between SeNB-2/3 and MeNB; among them, SeNB-3 and UE In -2, the wireless protocol stack corresponding to the SeNB part of DRB-3 has been established.

Taking the same downlink data as an example, Figure 5 is a schematic flow diagram of sending a status report between the SeNB node and the UE in the access network, and the specific steps are as follows:

Step 501: In the process of sending data to UE-2, the underlying protocol entities of SeNB-2 (such as PHY layer and MAC entity) will detect the signal status of the radio interface in real time through "RLC PDU for Split bearer". Taking RAT-1 as a high-frequency carrier and blockage occurs in its transmission path (that is, blockage is detected by PHY/MAC) as an example, SeNB-2 judges that RAT-1 cannot transmit data packets temporarily, then the RLC in SeNB-2 The entity immediately forwards the data packet in the buffer to SeNB-3 through the ideal interface (idealbackhaul). For example, the RLC entity in SeNB-2 forwards the RLC PDU (Forwarding the RLC PDU in buffer) in the buffer to SeNB-3 .

Step 502: After receiving the data packet forwarded by SeNB-2, SeNB-3 initiates polling (polling) to UE-2 through the RAT-2 carrier, that is, actively requests a status report from the receiving node of the data packet; at this time, SeNB In -3, the timer related to the state prohibition function of the RLC entity is in the off state.

Step 503: After UE-2 receives the polling (polling), check the status in the current buffer, generate a status report, and send the status report as soon as possible (that is, when the next transmission opportunity arrives, and jump into the queue to wait for the data packet to be transmitted Before) sending the status report to the peer entity (RLC entity in SeNB-3) through RAT-2. After the RLC entity in SeNB-3 receives the status report (StatusReport), it performs corresponding data packet retransmission and necessary re-segmentation according to the information indicated in it, and passes the retransmitted data packet and the subsequent first transmitted data packet through RAT-2 sends the RLC PDU (RLC PDU for Split bearer (Retransmission and Transmission)) to UE-2. The RLC entity in UE-2 combines the data packet in the buffer with the data packet received on RAT-2 Packets are combined for processing such as sorting and merging.

If the RAT-1 carrier of SeNB-2 recovers the signal quality meeting a certain threshold within a short period of time, then the data packet can be transferred back to SeNB-2 to continue transmission. Further, for the solution of switching back (from RAT-2 to RAT-1), reference may be made to the above-mentioned related operations when RAT-1 is changed to RAT-2. If the RAT-1 carrier quality of SeNB-2 has not recovered after a certain period of time, then SeNB-2 or SeNB-3 can pass the converted information to MeNB, and the MeNB will generate DRB after receiving the information Part of the RLC PDU of -3 is distributed to SeNB-2 for further transmission.

Embodiment three

Referring to the communication system architecture in FIG. 1b and the user plane wireless protocol stack mode in FIG. 2c, this embodiment mainly uses the SeNB node switching procedure as an example to illustrate the implementation process of data retransmission in the present invention.

Specifically, the serving base stations currently accessed by the UE in the DC state are MeNB and SeNB-1, where a control plane RRC connection is established between MeNB and the UE, and SeNB-1 communicates with the UE through the RAT-1 carrier supported by itself. A data packet of a DRB. It should be noted that there is a SeNB Anchor node within the coverage area of the MeNB, and the SeNB Anchor can have an S1-U interface with the S-GW in the core network, and all SeNB nodes within a certain range have an X2 interface with the SeNB Anchor. Interface and transmit user plane data with it. Wherein, each data bearing PDCP entity is established on the SeNB Anchor node, and each data bearing RLC entity and the following sublayers are established on the SeNB nodes within the range. In addition, the performance of the interface between SeNB nodes within the range of the SeNB Anchor is good, for example, SeNB-1 is connected to the neighboring node SeNB-2 (the wireless interface supports RAT-2 carrier) through ideal backhaul.

Similarly, the following row data is taken as an example, and FIG. 6 is a schematic flow chart of data retransmission in this embodiment:

Step 601: MeNB sends measurement configuration to UE and receives UE measurement report. According to measurement report and other radio resource management information, MeNB decides to handover UE from currently accessed SeNB-1 to SeNB-2. Therefore, MeNB requests SeNB-2 for radio resources related to the UE (the request message carries the RLC entity configuration parameters of SeNB-1 to DRB) and obtains an acknowledgment reply message from SeNB-2, and the message contains SeNB-2 Configure the radio resources of the UE and receive the tunnel address of the data packet forwarded by the SeNB-1. Among them, the messages exchanged between MeNB and SeNB-2 can be transmitted through SeNBanchor.

Step 602: After receiving the confirmation reply message from SeNB-2, the MeNB sends RRC signaling to the UE through the wireless interface to instruct the UE to leave the SeNB-1 cell and access the SeNB-2 cell, and rebuild the MAC according to the configuration information Entity and physical layer, however, the buffer and context in the RLC entity are not cleared; on the other hand, MeNB sends a message indicating node switching to SeNB-1 through the X2 interface, and the message carries the tunnel for SeNB-2 to receive and forward data packets address.

Among them, after receiving the RRC signaling from the MeNB, on the one hand, the UE leaves the SeNB-1 cell and initiates random access to the SeNB-2 cell; on the other hand, it creates a new MAC entity and PHY inside the node. If the RLC entity corresponding to SeNB-2 of the DRB is newly created, the original RLC entity corresponding to SeNB-1 forwards the data packet in the buffer and the SN status to the RLC entity corresponding to SeNB-2, and the original RLC entity can Delete; otherwise, the register in the original RLC entity can be kept unchanged. After the protocol entity reconfiguration is completed, the UE replies to the MeNB with RRC signaling indicating completion.

Wherein, SeNB-1 forwards the data packet and SN status in the RLC entity to SeNB-2 after receiving the X2 message from MeNB.

Step 603: After accessing the SeNB-2 cell, the UE checks the buffer status in its own RLC entity and sends a status report (Status Report) to SeNB-2 as soon as possible. After the RLC entity in SeNB-2 receives the Status Report, Perform corresponding data packet retransmission and necessary re-segmentation according to the information indicated therein, and send the retransmitted data packet and subsequent first-transmitted data packets to the UE through RAT-2. The RLC entity in the UE combines the data packets in the buffer with the data packets received on RAT-2 to perform processing such as sorting and merging. In terms of the X2 interface, SeNB-2 sends an indication message to the SeNB Anchor (Anchor) to notify the SeNB Anchor of path switching, so that the SeNB Anchor sends subsequent PDCP PDUs to SeNB-2 to continue transmission after receiving the indication message.

As shown in FIG. 7 , the embodiment of the present invention provides a data retransmission device deployed on an upper layer protocol entity, including: an indication module, a status reporting module, and a data packet receiving module; wherein,

The indication module is configured to receive an indication, the indication indicates that the first wireless carrier currently used to transmit the data packet is temporarily unavailable, or indicates that the user equipment UE is connected to the target node, or indicates a request for a status report;

A status report module, configured to generate a status report according to the status of the buffer, and send the status report to the peer protocol entity through the second wireless carrier;

The data packet receiving module is configured to receive the data packet retransmitted by the peer protocol entity.

Specifically, the indication module is configured to receive the indication sent by the underlying protocol entity in the node where the indication indicates that the first wireless carrier currently used to transmit data packets is temporarily unavailable; the second wireless carrier is The wireless carrier used by the UE and the source serving node after stopping the transmission of the first wireless carrier. Here, the indication is sent by the underlying protocol entity in the node when it detects that the signal quality of the first wireless carrier drops to a preset threshold or is completely interrupted.

Specifically, the indication module is configured to receive the indication sent by the underlying protocol entity in the node where the indication indicates that the UE accesses the target node; the second wireless carrier is the connection between the UE and the target node The wireless carrier used between. The status reporting module is further configured to receive the data packet and its serial number information in the buffer forwarded by the upper-layer protocol entity of the source serving node of the UE or the upper-layer protocol entity of the corresponding source serving node in the UE. Here, the upper layer protocol entity deploying the data retransmission device refers to the upper layer protocol entity corresponding to the source serving node in the UE, or the upper layer protocol entity corresponding to the target node.

Specifically, the indication module is configured to receive an indication on the second wireless carrier, where the indication is a polling request for a status report; The wireless carrier used after the transmission of the first wireless carrier, or the wireless carrier used between the UE and the target node.

Wherein, the data packet receiving module is further configured to sort and merge the data packets in the buffer and the received retransmission data packets.

Wherein, the upper layer protocol entity deploying the data retransmission device may be a protocol entity above the MAC entity in the data packet receiving node on the wireless interface; the peer protocol entity may be a data packet sending node on the wireless interface A protocol entity at the same protocol stack level as the upper protocol entity in the node; the underlying protocol entity may be a PHY entity or the MAC entity.

As shown in Figure 8, the embodiment of the present invention provides a data retransmission device deployed on the peer protocol entity of the upper layer protocol entity, including: a receiving module and a retransmission module; wherein, the receiving module is used to receive the upper layer protocol entity A status report sent by the protocol entity through the second wireless carrier, the status report is generated by the upper layer protocol entity according to the status of the buffer after receiving the indication that the first wireless carrier currently used to transmit data packets is temporarily unavailable , or indicates that the user equipment UE accesses the target node, or indicates a request for a status report; the retransmission module is configured to retransmit the data packet to the upper layer protocol entity.

Wherein, the receiving module may also be configured to receive a message sent by the underlying protocol entity in the node where the peer protocol entity is located, the message indicating that the first wireless carrier currently used to transmit data packets is temporarily unavailable, or the UE Access to the target node; the device may also include: a sending module, configured to send a polling request to the upper-layer protocol entity through the second wireless carrier, and request the upper-layer protocol entity to feed back a status report; the second The wireless carrier is the wireless carrier used by the UE and the source serving node after stopping the transmission of the first wireless carrier, or the wireless carrier used between the UE and the target node.

Specifically, the retransmission module may be configured to retransmit the data packet on the second wireless carrier according to the information in the status report. Here, the retransmission module is further configured to detect that the signal quality of the first wireless carrier recovers after a preset period of time, and that the first wireless carrier is superior to the second wireless carrier in terms of transmission rate or resource load. The wireless carrier, after completing the retransmission of the data packet, transfers the data packet back to the underlying protocol entity corresponding to the first wireless carrier for transmission.

In practical applications, the above-mentioned data retransmission device provided by the embodiment of the present invention can be used to implement the technical solution of the above-mentioned method embodiment, and its implementation principle and technical effect are similar, and will not be repeated here.

Although the embodiments disclosed in the present invention are as above, the described content is only an embodiment adopted for understanding the present invention, and is not intended to limit the present invention. Anyone skilled in the field of the present invention can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed by the present invention, but the patent protection scope of the present invention must still be The scope defined by the appended claims shall prevail.

Claims (26)

1. A method for retransmitting data, comprising:

the upper layer protocol entity receives an indication that a first radio carrier currently used for transmitting the data packet is temporarily unavailable, or indicates that the User Equipment (UE) is accessed to a target node, or indicates a request for a status report;

the upper layer protocol entity generates a state report according to the state of the buffer and sends the state report to an opposite end protocol entity through a second wireless carrier;

and the upper layer protocol entity receives the data packet retransmitted by the opposite end protocol entity.

2. The method of claim 1, wherein the upper layer protocol entity receives an indication that a first radio carrier currently used for transmitting the data packet is temporarily unavailable, comprising:

the upper layer protocol entity receives the indication sent by the bottom layer protocol entity in the node where the upper layer protocol entity is located, wherein the indication represents that the first wireless carrier currently used for transmitting the data packet is temporarily unavailable;

the second wireless carrier is a wireless carrier used by the UE and a source service node after stopping transmission of the first wireless carrier.

3. The method of claim 2, further comprising:

the indication is sent by a bottom layer protocol entity in the node when detecting that the signal quality of the first wireless carrier is reduced to a preset threshold or completely interrupted.

4. The method of claim 1, wherein the upper layer protocol entity receives an indication that the UE has access to a target node, comprising:

the upper layer protocol entity receives the indication sent by the bottom layer protocol entity in the node where the upper layer protocol entity is located, and the indication represents that the UE is accessed to the target node;

the second radio carrier is a radio carrier used between the UE and the target node.

5. The method of claim 4, wherein prior to the upper layer protocol entity receiving the indication, the method further comprises:

the upper protocol entity of the source service node of the UE forwards the data packet in the buffer and the number information thereof to the upper protocol entity positioned at the target node;

and the upper protocol entity corresponding to the source service node in the UE forwards the data packet in the buffer and the number information thereof to the upper protocol entity corresponding to the target node in the UE.

6. The method according to claim 4 or 5,

when the upper layer protocol entity is located in the UE, the upper layer protocol entity refers to an upper layer protocol entity corresponding to the source service node in the UE or an upper layer protocol entity corresponding to the target node.

7. The method of claim 1, wherein the upper layer protocol entity receives an indication that represents a request for a status report, comprising:

an upper layer protocol entity receives an indication on the second wireless carrier, the indication being a polling request for a status report;

the second wireless carrier is a wireless carrier used by the UE and a source serving node after stopping transmission of the first wireless carrier, or a wireless carrier used between the UE and the target node.

8. The method of claim 1, further comprising: and the upper layer protocol entity sequences and combines the data packet in the buffer with the received retransmission data packet.

9. The method according to any one of claims 1 to 8,

the upper layer protocol entity is a protocol entity above a Media Access Control (MAC) layer entity in a data packet receiving node on a wireless interface;

the opposite end protocol entity is a protocol entity which is in a data packet sending node on a wireless interface and is the same as the protocol stack level of the upper layer protocol entity;

the bottom layer protocol entity is a physical layer (PHY) entity or the MAC entity.

10. A method for retransmitting data, comprising:

an opposite end protocol entity receives a state report sent by an upper layer protocol entity through a second wireless carrier, wherein the state report is generated by the upper layer protocol entity according to the state of a buffer after receiving an indication, and the indication represents that a first wireless carrier currently used for transmitting a data packet is temporarily unavailable, or represents that User Equipment (UE) is accessed to a target node, or represents a request for the state report;

and the opposite end protocol entity retransmits the data packet to the upper layer protocol entity.

11. The method according to claim 10, wherein before the peer protocol entity receives the status report sent by the upper layer protocol entity through the second radio carrier, further comprising:

an opposite end protocol entity receives a message sent by a bottom layer protocol entity in a node where the opposite end protocol entity is located, wherein the message indicates that a first wireless carrier currently used for transmitting a data packet is temporarily unavailable or UE (user equipment) is accessed to a target node;

the opposite end protocol entity sends a polling request to the upper layer protocol entity through a second wireless carrier to request the upper layer protocol entity to feed back a state report;

the second wireless carrier is a wireless carrier used by the UE and a source serving node after stopping transmission of the first wireless carrier, or a wireless carrier used between the UE and the target node.

12. The method of claim 10, wherein the peer protocol entity retransmits the data packet to the upper layer protocol entity, comprising:

and the opposite end protocol entity retransmits the data packet on the second wireless carrier according to the information in the status report.

13. The method of claim 12, further comprising:

and if the signal quality of the first wireless carrier is detected to be recovered after a preset time period, and the first wireless carrier is superior to the second wireless carrier in transmission rate or resource load, the opposite-end protocol entity transfers the data packet back to the bottom-layer protocol entity corresponding to the first wireless carrier for transmission after the retransmission of the data packet is completed.

14. A data retransmission apparatus, comprising: the device comprises an indication module, a status report module and a data packet receiving module; wherein,

an indication module, configured to receive an indication that a first radio carrier currently used for transmitting a data packet is temporarily unavailable, or that a user equipment UE accesses a target node, or that a request for a status report is received;

the state report module is used for generating a state report according to the state of the buffer and sending the state report to the opposite terminal protocol entity through a second wireless carrier;

a data packet receiving module, configured to receive a data packet retransmitted by the peer protocol entity;

the data retransmission device is deployed in an upper layer protocol entity.

15. The apparatus of claim 14,

the indication module is configured to receive the indication sent by the bottom layer protocol entity in the node where the indication indicates that the first wireless carrier currently used for transmitting the data packet is temporarily unavailable;

the second wireless carrier is a wireless carrier used by the UE and a source service node after stopping transmission of the first wireless carrier.

16. The apparatus of claim 15, wherein the indication is issued by an underlying protocol entity within the node upon detecting that the signal quality of the first wireless carrier has dropped to a preset threshold or has been completely interrupted.

17. The apparatus of claim 14,

the indication module is used for receiving the indication sent by the bottom layer protocol entity in the node where the UE is located, wherein the indication represents that the UE is accessed to the target node;

the second radio carrier is a radio carrier used between the UE and the target node.

18. The apparatus of claim 17,

the status report module is further configured to receive a data packet and its number information in a buffer forwarded by an upper layer protocol entity of a source service node of the UE or the upper layer protocol entity of the corresponding source service node in the UE.

19. The apparatus of claim 17,

the upper layer protocol entity for deploying the data retransmission apparatus refers to an upper layer protocol entity corresponding to the source serving node in the UE, or an upper layer protocol entity corresponding to the target node.

20. The apparatus of claim 14,

the indication module is configured to receive an indication on the second radio carrier, where the indication is a polling request for a status report;

the second wireless carrier is a wireless carrier used by the UE and a source serving node after stopping transmission of the first wireless carrier, or a wireless carrier used between the UE and the target node.

21. The apparatus of claim 14, wherein the packet receiving module is further configured to order and combine the packets in the buffer with the received retransmitted packets.

22. The apparatus of any one of claims 14 to 21,

the upper layer protocol entity deployed with the data retransmission device is a protocol entity above a Media Access Control (MAC) layer entity in a data packet receiving node on a wireless interface;

the opposite end protocol entity is a protocol entity which is in a data packet sending node on a wireless interface and is the same as the protocol stack level of the upper layer protocol entity;

the bottom layer protocol entity is a physical layer (PHY) entity or the MAC entity.

23. A data retransmission apparatus, comprising: a receiving module and a retransmission module; wherein,

a receiving module, configured to receive a status report sent by an upper layer protocol entity through a second radio carrier, where the status report is generated by the upper layer protocol entity according to a status of a buffer after receiving an indication, where the indication indicates that a first radio carrier currently used for transmitting a data packet is temporarily unavailable, or indicates that a user equipment UE is accessed to a target node, or indicates a request for the status report;

a retransmission module, configured to retransmit a data packet to the upper layer protocol entity;

the data retransmission device is deployed at an opposite end protocol entity of the upper layer protocol entity.

24. The apparatus of claim 23,

the receiving module is further configured to receive a message sent by a bottom layer protocol entity in a node where the opposite end protocol entity is located, where the message indicates that a first wireless carrier currently used for transmitting a data packet is temporarily unavailable or that the UE is accessed to a target node;

the device further comprises: a sending module, configured to send a polling request to the upper layer protocol entity through the second radio carrier, and request the upper layer protocol entity to feed back a status report;

the second wireless carrier is a wireless carrier used by the UE and a source serving node after stopping transmission of the first wireless carrier, or a wireless carrier used between the UE and the target node.

25. The apparatus of claim 23,

and the retransmission module is used for retransmitting the data packet on the second wireless carrier according to the information in the status report.

26. The apparatus of claim 25,

the retransmission module is further configured to detect that the signal quality of the first wireless carrier is recovered after a preset time period, and the first wireless carrier is better than the second wireless carrier in transmission rate or resource load, and after completing retransmission of a data packet, transfer the data packet back to a bottom layer protocol entity corresponding to the first wireless carrier for transmission.