HK1226234B - Rlc data packet offloading method, and base station - Google Patents

Description

RLC data packet offloading method and base station

This application claims priority to two Chinese patent applications, application number PCT/CN2015/072572, filed with the Patent Office of China on February 9, 2015, entitled “A Method for Offloading RLC Data Packets and a Base Station”, and application number PCT/CN2015/088049, filed with the Patent Office of China on August 25, 2015, entitled “A Method for Offloading RLC Data Packets and a Base Station”, the entire contents of which are incorporated herein by reference.

Technical Field

The present invention relates to the field of communication technology, and in particular to an RLC data packet offloading method and a base station.

Background Art

The Long Term Evolution (LTE) system consists of the Evolved Packet Core (EPC), Evolved NodeBs (eNodeBs), and User Equipment (UE). The EPC is the core network component and includes the Mobility Management Entity (MME), responsible for signaling, and the Serving Gateway (SGW), responsible for data processing. The eNodeBs and EPC are connected via the S1 interface, eNodeBs are connected to each other via the X2 interface, and the eNodeBs and UEs are connected via the Uu interface.

The Evolved Universal Terrestrial Radio Access Network (E-UTRAN) consists of eNodeBs, which are responsible for radio-related functions. The E-UTRAN protocol framework is divided into user plane protocols and control plane protocols. The user plane protocol stack includes the Packet Data Convergence Protocol (PDCP), Radio Link Control (RLC), and Media Access Control (MAC).

Referring to Figure 1 , in the prior art, data packets can be transmitted from a PDCP entity to an RLC entity. RLC entities can operate in Transparent (TM), Unacknowledged (UM), and Acknowledged (AM) modes. Figure 1 shows an AM RLC entity.

For the carrier aggregation (CA) scenario of the heterogeneous network (HetNet) with ideal backhaul, in the AM mode of RLC, data packets can be diverted to the macro eNodeB (Macro eNodeB) belonging to the primary cell (Pcell) and the micro eNodeB (Micro eNodeB) belonging to the secondary cell (Scell), so that the data packets can be sent to the user equipment (UE) through the primary cell and the secondary cell respectively, thereby improving data transmission efficiency.

In actual networks, non-ideal backhaul is usually used between Macro eNodeB and Micro eNodeB. Due to the large transmission delay between Macro eNodeB and Micro eNodeB, the performance of UE in the CA scenario of HetNet with non-ideal backhaul is affected.

Summary of the Invention

The embodiments of the present invention provide an RLC data packet offloading method and a base station, so as to solve the problem that the transmission delay between macro and micro base stations is large, thereby affecting the performance of UE in a CA scenario with non-ideal backhaul HetNet.

A first aspect of the present invention provides an RLC data packet offloading method, comprising:

The macro base station receives an RLC data packet request message sent by the micro base station, wherein the RLC data packet request message is used by the micro base station to request the macro base station for a first number of RLC data packets sent by the micro base station to the CAUE through the secondary cell, and the RLC data packet request message is sent by the micro base station to the macro base station at a first moment, and the time difference between the first moment and the second moment is T, where T is greater than or equal to 2t, and the second moment is the moment when the micro base station sends the first number of RLC data packets to the UE, and t is the one-way transmission delay between the micro base station and the macro base station;

Determining, by the macro base station, a second number of RLC data packets to be sent by the macro base station to the UE through the primary cell within a T-t duration according to the RLC data packet request message, wherein a start time of the T-t duration is a time when the macro base station receives the RLC data packet request message;

In a descending order of sequence numbers of the RLC data packets to be sent, the macro base station allocates the first second number of RLC data packets from the RLC data packets to be sent to the macro base station, and allocates the first number of RLC data packets to the micro base station starting from the first RLC data packet with a sequence number after the first second number of RLC data packets;

The macro base station sends the first number of RLC data packets to the micro base station.

In combination with the first aspect, in a first possible implementation manner of the first aspect, the method further includes:

The macro base station sends the second number of RLC data packets to the UE through the primary cell.

In combination with the first possible implementation manner of the first aspect, in a second possible implementation manner of the first aspect, the method further includes:

The macro base station receives ACK/NACK information sent by the UE through the primary cell, where the ACK/NACK information includes feedback information of the UE for the first number of RLC data packets and feedback information of the UE for the second number of RLC data packets.

In combination with the second possible implementation manner of the first aspect, in a third possible implementation manner of the first aspect, after the macro base station receives the ACK/NACK information sent by the UE through the primary cell, the method further includes:

If the feedback information for the first number of RLC data packets received by the macro base station includes NACK, the macro base station determines whether the micro base station can obtain HARQ combining gain by performing HARQ on the RLC data packets corresponding to the NACK through the secondary cell;

If the HARQ combining gain can be obtained, the macro base station sends the NACK to the micro base station and instructs the micro base station to retransmit the RLC data packet to the UE using the HARQ method.

In combination with the third possible implementation manner of the first aspect, in a fourth possible implementation manner of the first aspect, the macro base station determines whether the micro base station can obtain a HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, specifically including:

When the macro base station determines that the number of HARQ processes currently used by the micro base station on the secondary cell is less than the maximum number of HARQ processes, the macro base station determines that the micro base station can obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell.

In combination with the third possible implementation manner or the fourth possible implementation manner of the first aspect, in a fifth possible implementation manner of the first aspect, the method further includes:

If the macro base station determines that the micro base station cannot obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, the macro base station retransmits the RLC data packet corresponding to the NACK to the UE through the primary cell in an ARQ manner.

In combination with the fifth possible implementation manner of the first aspect, in a sixth possible implementation manner of the first aspect, before the macro base station receives the ACK/NACK information sent by the UE through the primary cell, the method further includes:

The macro base station receives an RLC packetization result sent by the micro base station, where the RLC packetization result is used to indicate information about an RLC data packet transmitted by the micro base station to the UE through the secondary cell; wherein the RLC data packet transmitted by the micro base station to the UE through the secondary cell is part or all of the first number of RLC data packets;

The macro base station retransmitting the RLC data packet corresponding to the NACK to the UE through the primary cell in an ARQ manner specifically includes:

The macro base station retransmits the RLC data packet corresponding to the NACK to the UE through the primary cell in an ARQ manner according to the RLC packet assembly result.

In combination with the third possible implementation manner or the fourth possible implementation manner of the first aspect, in a seventh possible implementation manner of the first aspect, the method further includes:

If the macro base station determines that the micro base station cannot obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, the macro base station sends the NACK to the micro base station and instructs the micro base station to retransmit the RLC data packet corresponding to the NACK to the UE through the secondary cell in an ARQ manner.

A second aspect of the present invention provides an RLC data packet offloading method, comprising:

The micro base station sends an RLC data packet request message to the macro base station, wherein the RLC data packet request message is used by the micro base station to request the macro base station for a first number of RLC data packets sent by the micro base station to the CAUE through the secondary cell, and the RLC data packet request message is sent by the micro base station to the macro base station at a first moment, and the time difference between the first moment and the second moment is T, where T is greater than or equal to 2t, and the second moment is the moment when the micro base station sends the first number of RLC data packets to the UE, and t is the one-way transmission delay between the micro base station and the macro base station;

The micro base station receives the first number of RLC data packets sent by the macro base station, wherein the process of determining the first number of RLC data packets includes: according to the RLC data packet request message, the macro base station determines the second number of RLC data packets sent by the macro base station to the UE through the main cell within the T-t time length, wherein the starting time of the T-t time length is the time when the macro base station receives the RLC data packet request message, and the macro base station allocates the first second number of RLC data packets from the RLC data packets to be sent to the macro base station in the order of the sequence numbers of the RLC data packets to be sent from front to back, and allocates the first number of RLC data packets to the micro base station starting from the first RLC data packet with a sequence number after the first second number of RLC data packets.

In conjunction with the second aspect, in a first possible implementation manner of the second aspect, the method further includes:

The micro base station receives part or all of the feedback information of the UE for the first number of RLC data packets sent by the macro base station. The feedback information of the UE for the first number of RLC data packets belongs to the ACK/NACK information sent by the UE to the macro base station, and the ACK/NACK information also includes the feedback information of the UE for the second number of RLC data packets.

In combination with the first possible implementation manner of the second aspect, in a second possible implementation manner of the second aspect, before the micro base station receives the feedback information of the UE for the first number of RLC data packets sent by the macro base station, the method further includes:

The micro base station sends an RLC packetization result to the macro base station, and the RLC packetization result is used to indicate information of the RLC data packet transmitted by the micro base station to the UE through the secondary cell; wherein, the RLC data packet transmitted by the micro base station to the UE through the secondary cell is part or all of the first number of RLC data packets.

A third aspect of the present invention provides a macro base station, including:

A first receiving module is configured to receive an RLC data packet request message sent by a micro base station, wherein the RLC data packet request message is used by the micro base station to request the macro base station for a first number of RLC data packets sent by the micro base station to the CAUE through the secondary cell, and the RLC data packet request message is sent by the micro base station to the macro base station at a first moment, and the time difference between the first moment and the second moment is T, wherein T is greater than or equal to 2t, and the second moment is the moment when the micro base station sends the first number of RLC data packets to the UE, and t is a one-way transmission delay between the micro base station and the macro base station;

a determining module, configured to determine, based on the RLC data packet request message, a second number of RLC data packets sent by the macro base station to the UE through the primary cell within a T-t duration, wherein a start time of the T-t duration is a time when the macro base station receives the RLC data packet request message;

an allocating module, configured to allocate the first second number of RLC data packets from the RLC data packets to be sent to the macro base station in a descending order of the sequence numbers of the RLC data packets to be sent, and allocate the first number of RLC data packets to the micro base station starting from the first RLC data packet with a sequence number after the first second number of RLC data packets;

The first sending module is used to send the first number of RLC data packets to the micro base station.

In combination with the third aspect, in a first possible implementation manner of the third aspect, the macro base station further includes a second sending module, where the second sending module is configured to:

The second number of RLC data packets are sent to the UE through the primary cell.

In combination with the first possible implementation manner of the third aspect, in a second possible implementation manner of the third aspect, the macro base station further includes a second receiving module, where the second receiving module is configured to:

ACK/NACK information sent by the UE is received through the primary cell, where the ACK/NACK information includes feedback information of the UE for the first number of RLC data packets and feedback information of the UE for the second number of RLC data packets.

In combination with the second possible implementation manner of the third aspect, in a third possible implementation manner of the third aspect, the macro base station further includes a judgment module, configured to: after the second receiving module receives the ACK/NACK information sent by the UE through the primary cell, if the feedback information for the first number of RLC data packets in the ACK/NACK information includes NACK, then determine whether the micro base station can obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell;

The first sending module is further used to: if HARQ combining gain can be obtained, send the NACK to the micro base station and instruct the micro base station to retransmit the RLC data packet to the UE using the HARQ method.

In conjunction with the third possible implementation manner of the third aspect, in a fourth possible implementation manner of the third aspect, the judgment module is specifically configured to:

When it is determined that the number of HARQ processes currently used by the micro base station on the secondary cell is less than the maximum number of HARQ processes, it is determined that the micro base station can obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell.

In combination with the third possible implementation manner or the fourth possible implementation manner of the third aspect, in a fifth possible implementation manner of the third aspect, the macro base station further includes a retransmission module, configured to:

If the judgment module determines that the micro base station cannot obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, it retransmits the RLC data packet corresponding to the NACK to the UE in an ARQ manner through the primary cell and the second sending module.

In combination with the fifth possible implementation manner of the third aspect, in a sixth possible implementation manner of the third aspect, the first receiving module is further configured to:

Before the second receiving module receives the ACK/NACK information sent by the UE through the primary cell, the second receiving module receives an RLC packetization result sent by the micro base station, where the RLC packetization result is used to indicate information about the RLC data packets transmitted by the micro base station to the UE through the secondary cell; wherein the RLC data packets transmitted by the micro base station to the UE through the secondary cell are part or all of the first number of RLC data packets;

The retransmission module is specifically configured to: retransmit the RLC data packet corresponding to the NACK to the UE in an ARQ manner through the primary cell and the second sending module according to the RLC packet assembly result.

In combination with the third possible implementation manner or the fourth possible implementation manner of the third aspect, in a seventh possible implementation manner of the third aspect, the first sending module is further configured to:

If the judgment module determines that the micro base station cannot obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, the NACK will be sent to the micro base station, and the micro base station will be instructed to retransmit the RLC data packet corresponding to the NACK to the UE through the secondary cell in an ARQ manner.

A fourth aspect of the present invention provides a micro base station, comprising:

A first sending module is configured to send an RLC data packet request message to the macro base station, wherein the RLC data packet request message is used by the micro base station to request the macro base station for a first number of RLC data packets sent by the micro base station to the CAUE through the secondary cell. The RLC data packet request message is sent by the micro base station to the macro base station through the first sending module at a first moment. The time difference between the first moment and the second moment is T, wherein T is greater than or equal to 2t. The second moment is the moment when the micro base station sends the first number of RLC data packets to the UE through the second sending module, and t is the one-way transmission delay between the micro base station and the macro base station;

A first receiving module is used to receive the first number of RLC data packets sent by the macro base station, wherein the process of determining the first number of RLC data packets includes: according to the RLC data packet request message, the macro base station determines the second number of RLC data packets sent by the macro base station to the UE through the main cell within the T-t time period, wherein the starting time of the T-t time period is the time when the macro base station receives the RLC data packet request message, and the macro base station allocates the first second number of RLC data packets from the RLC data packets to be sent to the macro base station in order from the sequence numbers of the RLC data packets to be sent, and allocates the first number of RLC data packets to the micro base station starting from the first RLC data packet with a sequence number after the first second number of RLC data packets.

In combination with the fourth aspect, in a first possible implementation manner of the fourth aspect, the first receiving module is further configured to:

Receive part or all of the feedback information of the UE for the first number of RLC data packets sent by the macro base station, the feedback information of the UE for the first number of RLC data packets belongs to the ACK/NACK information sent by the UE to the macro base station, and the ACK/NACK information also includes the feedback information of the UE for the second number of RLC data packets.

In combination with the first possible implementation manner of the fourth aspect, in a second possible implementation manner of the fourth aspect, the first sending module is further configured to:

Before the first receiving module receives the feedback information of the UE for the first number of RLC data packets sent by the macro base station, the RLC packetization result is sent to the macro base station, and the RLC packetization result is used to indicate the information of the RLC data packets transmitted by the micro base station to the UE through the secondary cell and the second sending module; wherein, the RLC data packets transmitted by the micro base station to the UE through the secondary cell and the second sending module are part or all of the first number of RLC data packets.

A fifth aspect of the present invention provides a macro base station, comprising a memory, a processor, and an interface;

The memory is used to store instructions;

The interface is configured to receive an RLC data packet request message sent by a micro base station, wherein the RLC data packet request message is used by the micro base station to request the macro base station for a first number of RLC data packets sent by the micro base station to the CAUE through the secondary cell, and the RLC data packet request message is sent by the micro base station to the macro base station at a first moment, and the time difference between the first moment and the second moment is T, wherein T is greater than or equal to 2t, and the second moment is the moment when the micro base station sends the first number of RLC data packets to the UE, and t is the one-way transmission delay between the micro base station and the macro base station;

The processor calls the instructions of the memory, configured to execute: determining, according to the RLC data packet request message, a second number of RLC data packets to be sent by the macro base station to the UE through the primary cell within a T-t duration, wherein a start time of the T-t duration is a time when the macro base station receives the RLC data packet request message; and allocating the first second number of RLC data packets from the RLC data packets to be sent to the macro base station in a sequence from front to back of the sequence numbers of the RLC data packets to be sent, and allocating the first number of RLC data packets to the micro base station starting from a first RLC data packet with a sequence number after the first second number of RLC data packets;

The processor is further configured to send the first number of RLC data packets to the micro base station through the interface.

In combination with the fifth aspect, in a first possible implementation manner of the fifth aspect, the macro base station further includes a transceiver; and the processor is further configured to:

The second number of RLC data packets are sent to the UE through the primary cell and the transceiver.

In combination with the first possible implementation manner of the fifth aspect, in a second possible implementation manner of the fifth aspect, the transceiver is further configured to:

ACK/NACK information sent by the UE is received through the primary cell, where the ACK/NACK information includes feedback information of the UE for the first number of RLC data packets and feedback information of the UE for the second number of RLC data packets.

In combination with the second possible implementation manner of the fifth aspect, in a third possible implementation manner of the fifth aspect, the processor is further configured to:

After the transceiver receives the ACK/NACK information sent by the UE through the primary cell, if the feedback information for the first number of RLC data packets in the ACK/NACK information includes NACK, it is determined whether the micro base station can obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell; and, if the HARQ combining gain can be obtained, the NACK is sent to the micro base station through the interface, and the micro base station is instructed to retransmit the RLC data packet to the UE using the HARQ method.

In combination with the third possible implementation manner of the fifth aspect, in a fourth possible implementation manner of the fifth aspect, the processor is further configured to determine whether the micro base station can obtain a HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, specifically:

When it is determined that the number of HARQ processes currently used by the micro base station on the secondary cell is less than the maximum number of HARQ processes, it is determined that the micro base station can obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell.

In combination with the third possible implementation manner or the fourth possible implementation manner of the fifth aspect, in a fifth possible implementation manner of the fifth aspect, the processor is further configured to:

If it is determined that the micro base station cannot obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, the RLC data packet corresponding to the NACK is retransmitted to the UE in an ARQ manner through the primary cell and the transceiver.

In combination with the fifth possible implementation manner of the fifth aspect, in a sixth possible implementation manner of the fifth aspect, the interface is further used to: before the transceiver receives the ACK/NACK information sent by the UE through the primary cell, receive the RLC packetization result sent by the micro base station, where the RLC packetization result is used to indicate information about the RLC data packet transmitted by the micro base station to the UE through the secondary cell; wherein the RLC data packet transmitted by the micro base station to the UE through the secondary cell is part or all of the first number of RLC data packets;

The processor is also used to retransmit the RLC data packet corresponding to the NACK to the UE in an ARQ manner through the primary cell and the transceiver, specifically: according to the RLC packet grouping result, retransmit the RLC data packet corresponding to the NACK to the UE in an ARQ manner through the primary cell and the transceiver.

In combination with the third possible implementation manner or the fourth possible implementation manner of the fifth aspect, in a seventh possible implementation manner of the fifth aspect, the processor is further configured to:

If it is determined that the micro base station cannot obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, the NACK is sent to the micro base station through the interface, and the micro base station is instructed to retransmit the RLC data packet corresponding to the NACK to the UE through the secondary cell in an ARQ manner.

A sixth aspect of the present invention provides a micro base station, comprising a memory, a processor, an interface, and a transceiver;

The memory is used to store instructions;

The processor calls the instruction stored in the memory to execute: sending an RLC data packet request message to the macro base station through the interface, wherein the RLC data packet request message is used by the micro base station to request the macro base station for a first number of RLC data packets sent by the micro base station to the CAUE through the secondary cell, and the RLC data packet request message is sent by the processor to the macro base station through the interface at a first moment, the time difference between the first moment and the second moment is T, wherein T is greater than or equal to 2t, the second moment is the moment when the processor sends the first number of RLC data packets to the UE through the transceiver, and t is the one-way transmission delay between the micro base station and the macro base station;

The interface is used to receive the first number of RLC data packets sent by the macro base station, wherein the process of determining the first number of RLC data packets includes: based on the RLC data packet request message, the macro base station determines the second number of RLC data packets sent by the macro base station to the UE through the main cell within the T-t time period, wherein the starting time of the T-t time period is the time when the macro base station receives the RLC data packet request message, and the macro base station allocates the first second number of RLC data packets from the RLC data packets to be sent to the macro base station in the order of the sequence numbers of the RLC data packets to be sent from front to back, and allocates the first number of RLC data packets to the micro base station starting from the first RLC data packet with a sequence number after the first second number of RLC data packets.

In conjunction with the sixth aspect, in a first possible implementation of the sixth aspect, the interface is further used to:

Receive part or all of the feedback information of the UE for the first number of RLC data packets sent by the macro base station, the feedback information of the UE for the first number of RLC data packets belongs to the ACK/NACK information sent by the UE to the macro base station, and the ACK/NACK information also includes the feedback information of the UE for the second number of RLC data packets.

With reference to the first possible implementation manner of the sixth aspect, in a second possible implementation manner of the sixth aspect, the processor is further configured to:

Before the interface receives the feedback information of the UE for the first number of RLC data packets sent by the macro base station, the RLC packetization result is sent to the macro base station through the interface, and the RLC packetization result is used to indicate the information of the RLC data packets transmitted by the processor to the UE through the secondary cell and the transceiver; wherein, the RLC data packets transmitted by the processor to the UE through the secondary cell and the transceiver are part or all of the first number of RLC data packets.

In an embodiment of the present invention, the micro base station can request the required RLC data packet at the first moment before sending the RLC data packet to the UE, so that the macro base station can send the RLC data packet required by the micro base station to the micro base station in advance, thereby minimizing the transmission delay between the macro base station and the micro base station, and improving the UE's reception performance in the CA scenario of non-ideal backhaul HetNet.

In addition, in an embodiment of the present invention, the macro base station receives the RLC data packet request message from the micro base station in a time period of t, and then determines that the macro base station can send the second number of RLC data packets within the time period from the current moment to the second moment, and then allocates the first second number of RLC data packets with sequence numbers in front to the macro base station, and at the same time allocates the first number of RLC data packets with sequence numbers after the second number of RLC data packets to the micro base station, and the macro base station starts to send the second number of RLC data packets to the UE. Because the time required for the macro base station to send the second number of RLC data packets is the time period from the current moment to the second moment, when the macro base station finishes sending the second number of data packets, the micro base station receives and starts to send the first number of RLC data packets, and the sequence numbers between these RLC data packets are arranged in sequence, thereby ensuring the sequential sending of the RLC data packets, avoiding the UE from being unable to decode due to receiving out-of-order RLC data packets, and further improving the UE's receiving performance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of RLC data packet transmission of AM in the prior art;

FIG2 is a main flow chart of a method for offloading RLC data packets at a macro base station side according to an embodiment of the present invention;

FIG3 is a main flow chart of a method for offloading RLC data packets at a micro base station side according to an embodiment of the present invention;

FIG4A is a block diagram of the main structure of a macro base station according to an embodiment of the present invention;

FIG4B is a detailed structural block diagram of a macro base station according to an embodiment of the present invention;

FIG5A is a block diagram of the main structure of a micro base station according to an embodiment of the present invention;

FIG5B is a detailed structural block diagram of a micro base station according to an embodiment of the present invention;

FIG6A is a schematic diagram of the main structure of a macro base station according to an embodiment of the present invention;

FIG6B is a schematic diagram of the detailed structure of a macro base station according to an embodiment of the present invention;

FIG7 is a schematic diagram of the structure of a micro base station in an embodiment of the present invention.

DETAILED DESCRIPTION

To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

The technology described in this document may be applied to Universal Mobile Telecommunications System (UMTS), LTE system, and subsequent evolution systems of LTE.

The first base station receives an RLC data packet request message sent by the second base station, wherein the RLC data packet request message is used by the second base station to request the first base station for a first number of RLC data packets sent by the second base station to the CA UE through the secondary cell, and the RLC data packet request message is sent by the second base station to the first base station at a first moment, and a time difference between the first moment and the second moment is greater than or equal to 2t, the second moment is the moment when the second base station sends the first number of RLC data packets to the UE, and t is a one-way transmission delay between the second base station and the first base station;

determining, by the first base station, a second number of RLC data packets to be sent by the first base station to the UE through the primary cell according to the RLC data packet request message;

In a descending order of sequence numbers of the RLC data packets to be sent, the first base station allocates a first second number of RLC data packets from the RLC data packets to be sent to the first base station, and allocates the first number of RLC data packets to the second base station starting from a first RLC data packet with a sequence number after the first second number of RLC data packets;

The first base station sends the first number of RLC data packets to the second base station.

The second base station sends an RLC data packet request message to the first base station, wherein the RLC data packet request message is used by the second base station to request the first base station for a first number of RLC data packets sent by the second base station to the CA UE through the secondary cell. The RLC data packet request message is sent by the second base station to the first base station at a first moment, and a time difference between the first moment and the second moment is greater than or equal to 2t. The second moment is the moment when the second base station sends the first number of RLC data packets to the UE, and t is a one-way transmission delay between the second base station and the first base station.

The second base station receives the first number of RLC data packets sent by the first base station, wherein the process of determining the first number of RLC data packets includes: based on the RLC data packet request message, the first base station determines the second number of RLC data packets to be sent by the first base station to the UE through the main cell, and the first base station allocates the first second number of RLC data packets from the RLC data packets to be sent to the first base station in order from front to back of the sequence numbers of the RLC data packets to be sent, and allocates the first number of RLC data packets to the second base station starting from the first RLC data packet with a sequence number after the first second number of RLC data packets.

In the embodiments of the present invention, the receiving end is taken as an example.

The primary cell is a cell operating on the primary frequency band. The UE establishes a Radio Resource Control (RRC) connection with the Macro eNodeB through the primary cell.

A secondary cell is a cell operating on a secondary frequency band. When a CA-capable UE establishes an RRC connection with a Macro eNodeB, a secondary cell can be configured for the UE to provide additional radio resources.

In the embodiments of the present invention, a scenario in which a first base station and a second base station are networked is used for description. The first base station may be a macro base station or a micro base station. Similarly, the second base station may be a macro base station or a micro base station. The embodiments of the present invention do not limit the types of the first base station and the second base station. For example, the first base station and the second base station may both be macro base stations, or the first base station and the second base station may both be micro base stations, or the first base station may be a macro base station and the second base station may be a micro base station, or the first base station may be a micro base station and the second base station may be a macro base station, and so on. In the following description, the first base station is a macro base station and the second base station is a micro base station as an example.

Then, it should be noted that, for the convenience of description, the embodiment of the present invention is described in a HetNet scenario of macro and micro base station networking. The macro base station introduced in the embodiment of the present invention may also be replaced by a micro base station in some application scenarios. Similarly, the micro base station introduced in the embodiment of the present invention may also be replaced by a macro base station in some application scenarios. That is, the technical solution in the embodiment of the present invention is also applicable to networking scenarios between macro base stations and between micro base stations.

Additionally, the terms "system" and "network" are often used interchangeably in this document. The term "and/or" is simply a description of an association between related objects, indicating that three possible relationships exist. For example, "A and/or B" can mean: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, unless otherwise specified, the character "/" in this document generally indicates an "or" relationship between the related objects.

The embodiments of the present invention are described in further detail below with reference to the accompanying drawings.

Referring to FIG. 2 , an embodiment of the present invention provides an RLC data packet offloading method, and the main process of the method is described as follows.

Step 201: The macro base station receives an RLC data packet request message sent by the micro base station.

Among them, the RLC data packet request message is used by the micro base station to request the macro base station for the first number of RLC data packets sent by the micro base station to the CA UE through the secondary cell. The RLC data packet request message is sent by the micro base station to the macro base station at the first moment. The time difference between the first moment and the second moment is T, where T is greater than or equal to 2t. The second moment is the moment when the micro base station sends the first number of RLC data packets to the UE, and t is the one-way transmission delay between the micro base station and the macro base station.

Optionally, the one-way transmission delay can be obtained by measuring the transmission and reception of data packets with timestamps. Other methods for obtaining the one-way transmission delay are also within the protection scope of the embodiments of the present invention.

Optionally, the micro base station determines the first number of RLC data packets to be sent by the micro base station to the CA UE at the second moment based on any one or a combination of the quality of the wireless channel between the micro base station and the CA UE, the cell load of the secondary cell of the micro base station, and the spectrum efficiency of the CA UE in the secondary cell. The micro base station sends the first number to the macro base station through the RLC data packet request message, so that the micro base station requests the first number of RLC data packets from the macro base station.

Optionally, the micro base station sends the wireless channel quality between the micro base station and the CAUE, the cell load of the secondary cell of the micro base station, and the spectrum efficiency of the CA UE in the secondary cell to the macro base station through the RLC data packet request message, so that the micro base station requests the first number of RLC data packets from the macro base station. The macro base station determines the first number of RLC data packets that the micro base station can send to the CA UE at the second moment based on any one or a combination of the received wireless channel quality between the micro base station and the CAUE, the cell load of the secondary cell of the micro base station, and the spectrum efficiency of the CA UE in the secondary cell. Furthermore, the macro base station can also comprehensively consider any one or a combination of the wireless channel quality between the macro base station and the CAUE, the cell load of the primary cell of the macro base station, and the spectrum efficiency of the CA UE in the primary cell to determine the first number of RLC data packets that the micro base station can send to the CA UE at the second moment.

The wireless channel quality may be a channel quality indicator (CQI), a signal to interference plus noise ratio (SINR), a reference signal received power (RSRP), or a reference signal received quality (RSRQ).

Other parameters used by the base station to determine the number of RLC data packets to be sent to the UE, such as scheduling delay, scheduling data packet size, etc., are also within the protection scope of the embodiments of the present invention.

In the embodiment of the present invention, a UE with CA capability is referred to as a CA UE.

Optionally, before step 201, the method further includes:

A UE with CA capability is made to camp on the macro base station preferentially, that is, it is made to use the cell in the macro base station as its primary cell.

After the UE is preferentially camped on the macro base station, when the UE initiates service bearer establishment to the base station in the primary cell (i.e., the macro base station), the macro base station establishes an RLC data service logical channel for AM between the macro base station and the UE, and establishes an RLC data service logical channel for AM between the micro base station and the UE. The cell in the micro base station is the secondary cell of the UE.

Specifically, allowing UEs with CA capabilities to reside in the macro base station first and the macro base station to establish RLC data service logical channels respectively are both processes in the existing technology. The specific implementation method can refer to the existing technology, and the present invention does not limit this.

In this embodiment of the present invention, the micro base station knows when to start sending RLC data packets to the UE. Therefore, at the first moment before starting to send RLC data packets to the UE, the micro base station may first send the RLC data packet request message to the macro base station. The RLC data packet request message is used to request the macro base station to send RLC data packets to the micro base station. In this embodiment of the present invention, the number of RLC data packets required by the micro base station is referred to as the first number.

In the embodiment of the present invention, the time difference T between the first moment and the second moment is greater than or equal to 2t. Preferably, the time difference T between the first moment and the second moment is equal to 2t.

Step 202: The macro base station determines the second number of RLC data packets sent by the macro base station to the UE through the primary cell within the T-t duration based on the RLC data packet request message.

After receiving the RLC data packet request message, the macro base station determines the second number of RLC data packets sent by the macro base station to the CA UE through the main cell within the T-t time period, and the starting time of the T-t time period is the time when the macro base station receives the RLC data packet request message.

The macro base station determines the RLC data packets that the macro base station can transmit within the above-mentioned time length based on any one or a combination of the wireless signal quality between the macro base station and the CAUE, the cell load of the main cell of the macro base station, and the spectrum efficiency of the CA UE in the main cell, that is, determines the second number of RLC data packets sent by the macro base station to the CA UE through the main cell.

If the time difference between the first moment and the second moment is equal to 2t, then the time difference between the moment when the macro base station receives the RLC data packet request message and the second moment is t.

After receiving the RLC packet request message, the macro base station determines how many RLC packets the macro base station can transmit within the time period between the current moment and the second moment, and how much sequence number (SN) resources are required. For example, in this embodiment of the present invention, the number of RLC packets that the macro base station can transmit within this time period is referred to as the second number. Each RLC packet can have a sequence number. Both the macro base station and the micro base station transmit RLC packets sequentially based on the sequence number of the RLC packet. Therefore, the resources consumed by adding a sequence number to each RLC packet are SN resources.

For example, if the time difference between the first moment and the second moment is equal to 2t, then the macro base station needs to determine the number of RLC data packets that the macro base station can transmit within the future time period t and the SN resources consumed. That is, the second number is the number of RLC data packets that the macro base station can transmit within the future time period t. The future time period t mentioned here starts at the moment when the macro base station receives the RLC data packet request message.

Step 203: According to the order of the sequence numbers of the RLC data packets to be sent from front to back, the macro base station allocates the first second number of RLC data packets to the macro base station from the RLC data packets to be sent, and allocates the first number of RLC data packets to the micro base station starting from the first RLC data packet whose sequence number is after the first second number of RLC data packets.

For example, the macro base station determines that the second number is 50, that is, the macro base station will send 50 RLC data packets between the current moment and the second moment, and determines that the number of RLC data packets required by the micro base station is 30. Then the macro base station allocates the first 50 RLC data packets to the macro base station in descending order of the sequence numbers of the RLC data packets to be sent, starting from the first RLC data packet to be sent, and allocates the 30 RLC data packets starting from the 51st data packet to the micro base station.

Step 204: The macro base station sends the first number of RLC data packets to the micro base station.

That is, after allocating the first number of RLC data packets to the micro base station, the macro base station may send the first number of RLC data packets to the micro base station. When the micro base station receives the first number of RLC data packets, if the second time has arrived, the micro base station may directly start sending the first number of RLC data packets to the UE in sequence according to the sequence numbers of the RLC data packets.

Preferably, if the time difference between the first moment and the second moment is equal to 2t, then the moment when the micro base station receives the first number of RLC data packets may be exactly the second moment. The micro base station can send the RLC data packets immediately after receiving them, reducing the step that the micro base station needs to temporarily store the RLC data packets and saving storage resources.

Optionally, in an embodiment of the present invention, the method further includes:

The macro base station sends the second number of RLC data packets to the UE through the primary cell.

That is, after determining the second number of RLC data packets allocated to the macro base station, the macro base station can directly send the second number of RLC data packets to the UE.

For example, the time difference between the first moment and the second moment is equal to 2t. The macro base station determines that the second number is 50, meaning that the macro base station will send 50 RLC data packets between the current moment and the second moment, and determines that the number of RLC data packets required by the micro base station is 30. The macro base station then allocates the first 50 RLC data packets to the macro base station, starting with the first RLC data packet to be sent, in descending order of sequence numbers. The macro base station allocates the 30 RLC data packets starting with the 51st data packet to the micro base station. The macro base station then sends the 30 RLC data packets starting with the 51st data packet to the micro base station.

After allocating the first 50 RLC packets to the macro base station, the macro base station can directly send these first 50 RLC packets to the UE in sequence according to the sequence numbers of the RLC packets. When the macro base station sends the 50th RLC packet, the micro base station has just received the next 30 RLC packets. At the second moment, the micro base station also begins sending the 51st RLC packet to the UE in sequence according to the sequence numbers of the RLC packets. This ensures that the UE receives RLC packets sequentially, preventing decoding issues caused by out-of-order reception and improving UE reception performance. Furthermore, the transmission process has minimal delay, improving transmission efficiency.

In an embodiment of the present invention, the macro base station receives the RLC data packet request message from the micro base station in a time period of t, and then determines that the macro base station can send the second number of RLC data packets within the time period from the current moment to the second moment, and then allocates the first second number of RLC data packets with sequence numbers in front to the macro base station, and at the same time allocates the first number of RLC data packets with sequence numbers after the second number of RLC data packets to the micro base station, and the macro base station starts to send the second number of RLC data packets to the UE. Because the time required for the macro base station to send the second number of RLC data packets is the time period from the current moment to the second moment, when the macro base station finishes sending the second number of data packets, the micro base station receives and starts to send the first number of RLC data packets, and the sequence numbers between these RLC data packets are arranged in sequence, thereby ensuring the sequential sending of the RLC data packets, avoiding the UE from being unable to decode due to receiving out-of-order RLC data packets, and further improving the UE's receiving performance.

In the embodiment of the present invention, taking the receiving end as UE as an example, whether it is a macro base station or a micro base station, to send an RLC data packet to the UE, the RLC data packet can be sent to the air interface, and the UE receives it through the air interface.

After receiving the RLC data packet, the UE needs to feed back Acknowledgement (ACK)/Negative ACKnowledge (NACK) information to the macro base station according to the correctness of the received RLC data packet.

Optionally, in an embodiment of the present invention, the method further includes:

The macro base station receives ACK/NACK information sent by the UE through the primary cell, where the ACK/NACK information includes feedback information of the UE for the first number of RLC data packets and feedback information of the UE for the second number of RLC data packets.

Optionally, in the embodiment of the present invention, before the macro base station receives ACK/NACK information sent by the UE through the primary cell, the method further includes:

The macro base station receives the RLC packetization result sent by the micro base station, and the RLC packetization result is used to indicate the information of the RLC data packet transmitted by the micro base station to the UE through the secondary cell; wherein, the RLC data packet transmitted by the micro base station to the UE through the secondary cell is part or all of the first number of RLC data packets.

The micro base station may transmit all of the first number of RLC data packets allocated by the macro base station to the micro base station to the UE, or may only transmit a portion of them to the UE. For example, if the macro base station allocates a total of three RLC data packets to the micro base station, for example, 1, 2, and 3, the micro base station may transmit all of the three RLC data packets to the UE, and the RLC packetization result is used to indicate information about the three RLC data packets. Alternatively, the micro base station may only transmit 1 and 2 of the data packets to the UE, and the RLC packetization result is used to indicate information about the two RLC data packets 1 and 2. Alternatively, the micro base station may only transmit a portion of the data in 1 and 2 to the UE, and the RLC packetization result is used to indicate information about the portion of the data in 1 and 2 that is transmitted to the UE.

That is, although the macro base station knows which RLC data packets are allocated to the micro base station, the micro base station needs to tell the macro base station which part of the data packets is transmitted to the UE through the RLC packetization result.

For example, the micro base station can send the RLC packet result to the macro base station when sending the allocated RLC data packet to the receiving end (if the receiving end is the UE, it is sent to the air interface). In this way, the macro base station can know which RLC data the micro base station has transmitted to the UE.

Optionally, in the embodiment of the present invention, after the macro base station receives ACK/NACK information sent by the UE through the primary cell, the method further includes:

If the feedback information for the first number of RLC data packets received by the macro base station includes NACK, the macro base station determines whether the micro base station can obtain a hybrid automatic repeat reQuest (HARQ) combining gain by performing a HARQ on the RLC data packets corresponding to the NACK through the secondary cell;

If the HARQ combining gain can be obtained, the macro base station sends the NACK to the micro base station and instructs the micro base station to retransmit the RLC data packet to the UE using the HARQ method.

If the macro base station confirms that the received feedback information for the RLC data packet transmitted by the micro base station is NACK, the macro base station confirms that the RLC data packet corresponding to the NACK needs to be retransmitted.

If the macro base station determines that the RLC data packet corresponding to the NACK needs to be retransmitted, the macro base station can first determine whether the micro base station can obtain HARQ combining gain by performing HARQ on the RLC data packet through the secondary cell. For example, the micro base station transmits a total of three RLC data packets to the UE, namely RLC data packet 1, RLC data packet 2 and RLC data packet 3, then the UE will send feedback information for all three RLC data packets to the macro base station. For example, for RLC data packet 2, the feedback information sent by the UE is NACK, then the macro base station will determine whether the micro base station can obtain HARQ combining gain by performing HARQ on RLC data packet 2 through the secondary cell. If the macro base station determines that the micro base station can obtain HARQ combining gain by performing HARQ on RLC data packet 2 through the secondary cell, then the macro base station will send the NACK corresponding to RLC data packet 2 to the micro base station, and instruct the micro base station to retransmit RLC data packet 2 through HARQ.

Of course, if the feedback information received by the macro base station for the first number of RLC data packets includes ACKs, the macro base station directly sends these ACKs to the micro base station. For example, for RLC data packet 1 and RLC data packet 3, the feedback information sent by the UE is both ACK, then the macro base station sends both the ACK corresponding to RLC data packet 1 and the ACK corresponding to RLC data packet 3 to the micro base station.

Optionally, in an embodiment of the present invention, the macro base station determines whether the micro base station can obtain a HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, specifically including:

When the macro base station determines that the number of HARQ processes currently used by the micro base station on the secondary cell is less than the maximum number of HARQ processes, the macro base station determines that the micro base station can obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell.

If the number of HARQ processes currently used by the micro base station on the secondary cell is less than the maximum number of HARQ processes, indicating that there are idle HARQ processes, the macro base station can send the NACK to the micro base station and instruct the micro base station to retransmit the RLC data packet corresponding to the NACK in HARQ mode. After receiving the NACK sent by the macro base station and the instruction for instructing the micro base station to retransmit the RLC data packet corresponding to the NACK in HARQ mode, the micro base station will retransmit the RLC data packet corresponding to the NACK to the UE through the secondary cell in HARQ mode. The micro base station can directly use the idle HARQ process to retransmit the RLC data packet corresponding to the NACK. The retransmission delay is small and basically does not affect the UE's throughput. The UE can normally obtain the HARQ combining gain.

However, if the number of HARQ processes currently used by the micro base station on the secondary cell is not less than the maximum number of HARQ processes, the micro base station needs to wait until there is an idle HARQ process before it can retransmit the RLC data packet corresponding to the NACK to the UE, which results in a large retransmission delay. In this case, if the micro base station continues to retransmit the RLC data packet corresponding to the NACK using the HARQ method through the secondary cell, the UE cannot obtain the HARQ combining gain. Therefore, this method is used to determine whether the micro base station can obtain the HARQ combining gain by performing HARQ on the RLC data packet through the secondary cell.

In an embodiment of the present invention, if the macro base station determines that the micro base station cannot obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, the macro base station has two processing methods:

The first way: the macro base station retransmits the RLC data packet corresponding to the NACK to the UE through the primary cell in an automatic repeat reQuest (ARQ) manner.

The second way: the macro base station instructs the micro base station to retransmit the RLC data packet corresponding to the NACK to the UE through the secondary cell in an ARQ manner.

They are introduced below.

First way:

Optionally, in an embodiment of the present invention, after the macro base station determines whether the micro base station can obtain a HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, the method may further include:

If the macro base station determines that the micro base station cannot obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, the macro base station retransmits the RLC data packet corresponding to the NACK to the UE through the primary cell in an ARQ manner.

Optionally, in the embodiment of the present invention, the macro base station retransmitting the RLC data packet corresponding to the NACK to the UE through the primary cell in an ARQ manner specifically includes:

The macro base station retransmits the RLC data packet corresponding to the NACK to the UE through the primary cell in an ARQ manner according to the RLC packet assembly result.

That is, if the macro base station determines that the micro base station cannot obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, then one method that the macro base station can adopt is: to retransmit the RLC data packet corresponding to the NACK to the UE through ARQ.

Because before step 201, the macro base station has obtained the RLC packetization result and knows which RLC data packets the micro base station has transmitted to the UE, the macro base station can directly transmit the RLC data packet corresponding to the NACK to the UE through ARQ.

In the prior art, even if the macro base station wants to retransmit the RLC data packet, it needs to wait for the SN status report fed back by the UE first. Only after receiving the SN status report can it know which RLC data packets the micro base station has transmitted to the UE, and then the macro base station can retransmit some or all of the RLC data packets. It can be seen that the technical solution in the embodiment of the present invention shortens the RLC service interaction time and improves the transmission efficiency compared with the prior art.

Second way:

Optionally, in an embodiment of the present invention, the method may further include:

If the macro base station determines that the micro base station cannot obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, the macro base station sends the NACK to the micro base station and instructs the micro base station to retransmit the RLC data packet corresponding to the NACK to the UE through the secondary cell in an ARQ manner.

If the macro base station determines that the micro base station cannot obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, the macro base station may adopt another method of sending the NACK to the micro base station and instructing the micro base station to retransmit the RLC data packet corresponding to the NACK to the UE through the secondary cell in an ARQ manner. After receiving the NACK sent by the macro base station and the instruction instructing the micro base station to retransmit the RLC data packet corresponding to the NACK through the secondary cell in an ARQ manner, the micro base station will retransmit the RLC data packet corresponding to the NACK to the UE through the secondary cell in an ARQ manner.

For example, in a frequency division duplexing (FDD) system, the number of HARQ processes (IDs) specified in the protocol is 8 (i.e., the maximum number of HARQ IDs available on the air interface). However, due to the existence of the HARQ round-trip time (RTT), the actual HARQ RTT is 8+N (N refers to the unidirectional link delay between stations). In extreme scenarios, this may result in insufficient available HARQ IDs. In the prior art, when all 8 HARQ IDs on the secondary cell have been used and no HARQ ID has been released, if the micro base station still has new RLC data packets that need to be retransmitted, the retransmission will not be performed temporarily, but will wait until there is an idle HARQ ID before retransmitting. That is, due to insufficient HARQ IDs, RLC data packets cannot be sent for some time, resulting in a loss of UE throughput. Generally speaking, the UE's throughput loss is negatively increased by N/(8+N)*100%.

Furthermore, in the prior art, if all eight HARQ IDs are already in use and have not been released, and a new RLC packet needs to be transmitted, HARQ multiplexing can be used. This occupies an already used HARQ ID and sets the RLC packet for that HARQ ID as the newly transmitted RLC packet. This results in the RLC packet last sent by the occupied HARQ ID being sent to the receiver as a newly transmitted RLC packet when HARQ retransmission is required, and cannot be processed as a retransmitted RLC packet, resulting in the receiver being unable to obtain HARQ combining gain.

After adopting the method in the embodiment of the present invention, the macro base station first determines whether the number of HARQ IDs currently used by the micro base station on the secondary cell is less than the maximum number of HARQ IDs (i.e., the maximum number of HARQ processes). If so, it is determined that there are idle HARQ IDs available for retransmitting RLC data packets, and the RLC data packets to be retransmitted can be transmitted in a timely manner, that is, the receiving end can obtain HARQ combining gain. If the number of HARQ IDs currently used by the micro base station on the secondary cell is not less than the maximum number of HARQ IDs, generally speaking, the number of HARQ IDs currently used by the micro base station on the secondary cell is equal to the maximum number of HARQ IDs, indicating that there are no idle HARQ IDs for retransmitting new RLC data packets, then the new RLC data packets may not be transmitted in a timely manner. In this case, the HARQ method can be abandoned in the embodiment of the present invention, and the ARQ method can be used to retransmit the new RLC data packets, so that the RLC data packets can be retransmitted as soon as possible, reducing the delay required for data packet retransmission, and improving the efficiency of data packet retransmission.

Referring to FIG. 3 , based on the same inventive concept, an embodiment of the present invention provides another RLC data packet offloading method, the main process of which is described as follows.

Step 301: The micro base station sends an RLC data packet request message to the macro base station.

Among them, the RLC data packet request message is used by the micro base station to request the macro base station for the first number of RLC data packets sent by the micro base station to the CA UE through the secondary cell. The RLC data packet request message is sent by the micro base station to the macro base station at the first moment. The time difference between the first moment and the second moment is T, where T is greater than or equal to 2t. The second moment is the moment when the micro base station sends the first number of RLC data packets to the UE, and t is the one-way transmission delay between the micro base station and the macro base station.

Step 302: The micro base station receives the first number of RLC data packets sent by the macro base station.

After receiving the RLC data packet request message, the macro base station determines the second number of RLC data packets sent by the macro base station to the CA UE through the main cell within the T-t time period, and the starting time of the T-t time period is the time when the macro base station receives the RLC data packet request message.

Among them, the process of determining the first number of RLC data packets includes: according to the RLC data packet request message, the macro base station determines the second number of RLC data packets sent by the macro base station to the UE through the main cell within the T-t time length, wherein the starting time of the T-t time length is the time when the macro base station receives the RLC data packet request message, and the macro base station allocates the first second number of RLC data packets from the RLC data packets to be sent to the macro base station in the order of the sequence numbers of the RLC data packets to be sent from front to back, and allocates the first number of RLC data packets to the micro base station starting from the first RLC data packet with a sequence number after the first second number of RLC data packets.

Optionally, in an embodiment of the present invention, after the micro base station receives the first number of RLC data packets sent by the macro base station, the method further includes:

The micro base station sends the first number of RLC data packets to the UE.

Optionally, in the embodiment of the present invention, after the micro base station sends the first number of RLC data packets to the UE, the method may further include:

The micro base station receives part or all of the feedback information of the UE for the first number of RLC data packets sent by the macro base station. The feedback information of the UE for the first number of RLC data packets belongs to the ACK/NACK information sent by the UE to the macro base station, and the ACK/NACK information also includes the feedback information of the UE for the second number of RLC data packets.

That is, the UE sends feedback information for the first number of RLC data packets to the macro base station. After receiving the feedback information for the first number of RLC data packets, if there is ACK, the macro base station directly sends the ACK to the micro base station. If there is NACK, the macro base station will determine whether the micro base station can obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell. If it can be obtained, the macro base station will send NACK to the micro base station and instruct the micro base station to perform HARQ on the RLC data packet corresponding to the NACK. After receiving the NACK and the instruction of the macro base station, the micro base station will retransmit the RLC data packet corresponding to the NACK to the UE through the secondary cell in HARQ manner. However, if the macro base station determines that the micro base station cannot obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, the macro base station has two processing methods: one is that the macro base station still sends the NACK to the micro base station and instructs the micro base station to perform ARQ on the RLC data packet corresponding to the NACK to the UE. Then, after receiving the NACK and the instruction of the macro base station, the micro base station will retransmit the RLC data packet corresponding to the NACK to the UE through the secondary cell in ARQ mode. The other is that the macro base station retransmits the RLC data packet corresponding to the NACK to the UE through the primary cell in ARQ mode. In this case, the macro base station may not send the NACK to the micro base station.

Optionally, in the embodiment of the present invention, before the micro base station receives the feedback information of the UE for the first number of RLC data packets sent by the macro base station, the method further includes:

The micro base station sends an RLC packetization result to the macro base station, and the RLC packetization result is used to indicate information of the RLC data packet transmitted by the micro base station to the UE through the secondary cell; wherein, the RLC data packet transmitted by the micro base station to the UE through the secondary cell is part or all of the first number of RLC data packets.

If the macro base station determines that the micro base station cannot obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to NACK through the secondary cell, and the macro base station retransmits the RLC data packet corresponding to the NACK to the UE through the main cell in ARQ mode, because the macro base station has obtained the RLC packet grouping result and knows which RLC data packets the micro base station has specifically transmitted to the UE, the macro base station can directly transmit the RLC data packet corresponding to the NACK to the UE in ARQ mode.

In the prior art, even if the macro base station wants to retransmit the RLC data packet, it needs to wait for the SN status report fed back by the UE first. Only after receiving the SN status report can it know which RLC data packets the micro base station has transmitted to the UE, and then the macro base station can retransmit some or all of the RLC data packets. It can be seen that the technical solution in the embodiment of the present invention shortens the RLC service interaction time and improves the transmission efficiency compared with the prior art.

Any relevant details of the implementation of the embodiment of Figure 3 that are not introduced in the embodiment of Figure 3 have been introduced in the embodiment of Figure 2. Please refer to the embodiment of Figure 2 for details and will not be described in detail here.

Please refer to Figure 4A. Based on the same inventive concept, an embodiment of the present invention provides a macro base station, which may include a first receiving module 401, a determining module 402, an allocating module 403 and a first sending module 404.

A first receiving module 401 is configured to receive an RLC data packet request message sent by a micro base station, wherein the RLC data packet request message is used by the micro base station to request the macro base station for a first number of RLC data packets sent by the micro base station through a secondary cell CA UE. The RLC data packet request message is sent by the micro base station to the macro base station at a first moment, and the time difference between the first moment and the second moment is T, where T is greater than or equal to 2t. The second moment is the moment when the micro base station sends the first number of RLC data packets to the UE, and t is a one-way transmission delay between the micro base station and the macro base station.

A determining module 402 is configured to determine, according to the RLC data packet request message, a second number of RLC data packets sent by the macro base station to the UE through the primary cell;

After the first receiving module 401 receives the RLC data packet request message, the determining module 402 determines a second number of RLC data packets sent by the macro base station to the CA UE through the primary cell within a time period T-t, where a start time of the T-t time period is a time when the macro base station receives the RLC data packet request message;

an allocating module 403, configured to allocate the first second number of RLC data packets from the RLC data packets to be sent to the macro base station in a descending order of the sequence numbers of the RLC data packets to be sent, and allocate the first number of RLC data packets to the micro base station starting from the first RLC data packet with a sequence number after the first second number of RLC data packets;

The first sending module 404 is configured to send the first number of RLC data packets to the micro base station.

Optionally, referring to FIG. 4B , in the embodiment of the present invention, the macro base station further includes a second sending module 405 , and the second sending module 405 is configured to:

The second number of RLC data packets are sent to the UE through the primary cell.

Optionally, referring to FIG. 4B , in the embodiment of the present invention, the macro base station further includes a second receiving module 406 , and the second receiving module 406 is configured to:

ACK/NACK information sent by the UE is received through the primary cell, where the ACK/NACK information includes feedback information of the UE for the first number of RLC data packets and feedback information of the UE for the second number of RLC data packets.

Optionally, please continue to refer to FIG. 4B , in an embodiment of the present invention,

The macro base station further includes a judgment module 407, which is configured to: after the second receiving module 406 receives the ACK/NACK information sent by the UE through the primary cell, if the feedback information for the first number of RLC data packets in the ACK/NACK information includes NACK, determine whether the micro base station can obtain a HARQ combining gain by performing HARQ on the RLC data packets corresponding to the NACK through the secondary cell;

The first sending module 404 is further configured to: if HARQ combining gain can be obtained, send the NACK to the micro base station, and instruct the micro base station to retransmit the RLC data packet to the UE using the HARQ method.

Optionally, in the embodiment of the present invention, the determination module 407 is specifically configured to:

When it is determined that the number of HARQ processes currently used by the micro base station on the secondary cell is less than the maximum number of HARQ processes, it is determined that the micro base station can obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell.

Optionally, referring to FIG. 4B , in the embodiment of the present invention, the macro base station further includes a retransmission module 408 , which is configured to:

If the judgment module 407 determines that the micro base station cannot obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, the RLC data packet corresponding to the NACK is retransmitted to the UE in an ARQ manner through the primary cell and the second sending module 405.

Optionally, in an embodiment of the present invention,

The first receiving module 401 is further configured to:

Before the second receiving module 406 receives the ACK/NACK information sent by the UE through the primary cell, it receives an RLC packetization result sent by the micro base station, where the RLC packetization result is used to indicate information about the RLC data packets transmitted by the micro base station to the UE through the secondary cell; wherein the RLC data packets transmitted by the micro base station to the UE through the secondary cell are part or all of the first number of RLC data packets;

The retransmission module 408 is specifically configured to retransmit the RLC data packet corresponding to the NACK to the UE in an ARQ manner through the primary cell and the second sending module 405 according to the RLC packet assembly result.

Optionally, in the embodiment of the present invention, the first sending module 404 is further configured to:

If the judgment module 407 determines that the micro base station cannot obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, the NACK will be sent to the micro base station, and the micro base station will be instructed to retransmit the RLC data packet corresponding to the NACK to the UE through the secondary cell in an ARQ manner.

Please refer to Figure 5A. Based on the same inventive concept, an embodiment of the present invention provides a micro base station, which may include a first sending module 501 and a first receiving module 502.

A first sending module 501 is configured to send an RLC data packet request message to a macro base station, wherein the RLC data packet request message is used by the micro base station to request the macro base station for a first number of RLC data packets to be sent by the micro base station to a CA UE through a secondary cell. The RLC data packet request message is sent by the micro base station to the macro base station through the first sending module at a first moment. The time difference between the first moment and the second moment is T, wherein T is greater than or equal to 2t. The second moment is the moment when the micro base station sends the first number of RLC data packets to the UE through a second sending module 503 (see FIG. 5B , the micro base station further includes a second sending module 503). t is a one-way transmission delay between the micro base station and the macro base station.

The first receiving module 502 is used to receive the first number of RLC data packets sent by the macro base station, wherein the process of determining the first number of RLC data packets includes: according to the RLC data packet request message, the macro base station determines the second number of RLC data packets sent by the macro base station to the UE through the main cell within the T-t time period, wherein the starting time of the T-t time period is the time when the macro base station receives the RLC data packet request message, and the macro base station allocates the first second number of RLC data packets from the RLC data packets to be sent to the macro base station in the order of the sequence numbers of the RLC data packets to be sent from front to back, and allocates the first number of RLC data packets to the micro base station starting from the first RLC data packet with a sequence number after the first second number of RLC data packets.

Optionally, in the embodiment of the present invention, the first receiving module 502 is further configured to:

Receive part or all of the feedback information of the UE for the first number of RLC data packets sent by the macro base station, the feedback information of the UE for the first number of RLC data packets belongs to the ACK/NACK information sent by the UE to the macro base station, and the ACK/NACK information also includes the feedback information of the UE for the second number of RLC data packets.

Optionally, in the embodiment of the present invention, the first sending module 501 is further configured to:

Before the first receiving module 502 receives the feedback information of the UE for the first number of RLC data packets sent by the macro base station, the RLC packetization result is sent to the macro base station, and the RLC packetization result is used to indicate the information of the RLC data packets transmitted by the micro base station to the UE through the secondary cell and the second sending module 503; wherein, the RLC data packets transmitted by the micro base station to the UE through the secondary cell and the second sending module 503 are part or all of the first number of RLC data packets.

Optionally, in the embodiment of the present invention, the second sending module 503 is further configured to: send the first number of RLC data packets to the UE.

Optionally, in an embodiment of the present invention, the second sending module 503 is further configured to retransmit the RLC data packet corresponding to the NACK to the UE in a HARQ or ARQ manner through the secondary cell according to an instruction of the macro base station.

Please refer to Figure 6A. Based on the same inventive concept, an embodiment of the present invention provides a macro base station. The macro base station may include a memory 601 connected to a bus 600, a processor 602, and an interface 603.

Memory 601, used to store instructions required by processor 602 to perform tasks;

Interface 603, used to receive an RLC data packet request message sent by the micro base station, wherein the RLC data packet request message is used by the micro base station to request the macro base station for a first number of RLC data packets sent by the micro base station to the CA UE through the secondary cell, and the RLC data packet request message is sent by the micro base station to the macro base station at a first moment, and the time difference between the first moment and the second moment is T, where T is greater than or equal to 2t, and the second moment is the moment when the micro base station sends the first number of RLC data packets to the UE, and t is the one-way transmission delay between the micro base station and the macro base station;

The processor 602 calls the instructions stored in the memory 601 to execute: determining, according to the RLC data packet request message, a second number of RLC data packets to be sent by the macro base station to the UE through the primary cell; and allocating, from the RLC data packets to be sent, the first second number of RLC data packets to the macro base station in a sequence from front to back of the sequence numbers of the RLC data packets to be sent, and allocating, starting from the first RLC data packet with a sequence number after the first second number of RLC data packets, the first number of RLC data packets to the micro base station;

Specifically, the processor 602 is configured to: after receiving the RLC data packet request message through the interface 603, determine a second number of RLC data packets sent by the macro base station to the CA UE through the primary cell within a time period T-t, where a start time of the T-t time period is a time when the RLC data packet request message is received;

The processor 602 is further configured to send the first number of RLC data packets to the micro base station through the interface 603 .

Optionally, referring to Figure 6B, in an embodiment of the present invention, the macro base station further includes a transceiver 604 connected to the bus 600; the processor 602 is further used to: send the second number of RLC data packets to the UE through the main cell and via the transceiver 604.

Optionally, in an embodiment of the present invention, the transceiver 604 is further used to: receive ACK/NACK information sent by the UE through the primary cell, the ACK/NACK information including feedback information of the UE for the first number of RLC data packets and feedback information of the UE for the second number of RLC data packets.

Optionally, in this embodiment of the present invention, the processor 602 is further configured to:

After the transceiver 604 receives the ACK/NACK information sent by the UE through the primary cell, if the feedback information for the first number of RLC data packets in the ACK/NACK information includes NACK, it is determined whether the micro base station can obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell; and, if the HARQ combining gain can be obtained, the NACK is sent to the micro base station through the interface 603, and the micro base station is instructed to retransmit the RLC data packet to the UE using the HARQ method.

Optionally, in the embodiment of the present invention, the processor 602 is further configured to determine whether the micro base station can obtain a HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, specifically:

When it is determined that the number of HARQ processes currently used by the micro base station on the secondary cell is less than the maximum number of HARQ processes, it is determined that the micro base station can obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell.

Optionally, in this embodiment of the present invention, the processor 602 is further configured to:

If it is determined that the micro base station cannot obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, the RLC data packet corresponding to the NACK is retransmitted to the UE in an ARQ manner through the primary cell via the transceiver 604.

Optionally, in an embodiment of the present invention,

The interface 603 is further configured to: before the transceiver 604 receives the ACK/NACK information sent by the UE through the primary cell, receive an RLC packetization result sent by the micro base station, where the RLC packetization result is used to indicate information about the RLC data packet transmitted by the micro base station to the UE through the secondary cell; wherein the RLC data packet transmitted by the micro base station to the UE through the secondary cell is part or all of the first number of RLC data packets;

The processor 602 is also used to retransmit the RLC data packet corresponding to the NACK to the UE in an ARQ manner through the primary cell and the transceiver 604, specifically: according to the RLC packet grouping result, the RLC data packet corresponding to the NACK is retransmitted to the UE in an ARQ manner through the primary cell and the transceiver 604.

Optionally, in this embodiment of the present invention, the processor 602 is further configured to:

If it is determined that the micro base station cannot obtain HARQ combining gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, the NACK is sent to the micro base station through interface 603, and the micro base station is instructed to retransmit the RLC data packet corresponding to the NACK to the UE through the secondary cell in an ARQ manner.

Please refer to Figure 7. Based on the same inventive concept, an embodiment of the present invention provides a micro base station, which may include a memory 701 connected to a bus 700, a processor 702, an interface 703 and a transceiver 704.

Memory 701, used to store instructions required by processor 702 to perform tasks;

The processor 702 calls the instruction stored in the memory 701 to execute: sending an RLC data packet request message to the macro base station through the interface 703, wherein the RLC data packet request message is used by the micro base station to request the macro base station for the first number of RLC data packets sent by the micro base station to the CA UE through the secondary cell, and the RLC data packet request message is sent by the processor 702 to the macro base station through the interface 703 at a first moment, and the time difference between the first moment and the second moment is T, where T is greater than or equal to 2t, and the second moment is the moment when the processor 702 sends the first number of RLC data packets to the UE through the transceiver 704, and t is the one-way transmission delay between the micro base station and the macro base station;

Interface 703 is used to receive the first number of RLC data packets sent by the macro base station, wherein the process of determining the first number of RLC data packets includes: based on the RLC data packet request message, the macro base station determines the second number of RLC data packets sent by the macro base station to the UE through the main cell within the T-t time period, wherein the starting time of the T-t time period is the time when the macro base station receives the RLC data packet request message, and the macro base station allocates the first second number of RLC data packets from the RLC data packets to be sent to the macro base station in the order of the sequence numbers of the RLC data packets to be sent from front to back, and allocates the first number of RLC data packets to the micro base station starting from the first RLC data packet with a sequence number after the first second number of RLC data packets.

Optionally, in an embodiment of the present invention, interface 703 is also used to: receive part or all of the feedback information of the UE for the first number of RLC data packets sent by the macro base station, the feedback information of the UE for the first number of RLC data packets belongs to the ACK/NACK information sent by the UE to the macro base station, and the ACK/NACK information also includes the feedback information of the UE for the second number of RLC data packets.

Optionally, in this embodiment of the present invention, the processor 702 is further configured to:

Before interface 703 receives the feedback information of the UE for the first number of RLC data packets sent by the macro base station, the RLC packetization result is sent to the macro base station through interface 703, and the RLC packetization result is used to indicate the information of the RLC data packet transmitted to the UE by the processor 702 through the secondary cell and via the transceiver 704; wherein, the RLC data packet transmitted to the UE by the processor 702 through the secondary cell and via the transceiver 704 is part or all of the first number of RLC data packets.

Optionally, in this embodiment of the present invention, the processor 702 is further configured to: send the first number of RLC data packets to the UE through the transceiver 704 .

Optionally, in an embodiment of the present invention, the processor 702 is further configured to, according to an instruction of the macro base station, retransmit the RLC data packet corresponding to the NACK to the UE in a HARQ or ARQ manner through the secondary cell and the transceiver 704 .

In an embodiment of the present invention, the micro base station can request the required RLC data packet at the first moment before sending the RLC data packet to the UE, so that the macro base station can send the RLC data packet required by the micro base station to the micro base station in advance, thereby minimizing the transmission delay between the macro base station and the micro base station, and improving the UE's reception performance in the CA scenario of non-ideal backhaul HetNet.

In addition, in an embodiment of the present invention, the macro base station receives the RLC data packet request message from the micro base station in a time period of t, and then determines that the macro base station can send the second number of RLC data packets within the time period from the current moment to the second moment, and then allocates the first second number of RLC data packets with sequence numbers in front to the macro base station, and at the same time allocates the first number of RLC data packets with sequence numbers after the second number of RLC data packets to the micro base station, and the macro base station starts to send the second number of RLC data packets to the UE. Because the time required for the macro base station to send the second number of RLC data packets is the time period from the current moment to the second moment, when the macro base station finishes sending the second number of data packets, the micro base station receives and starts to send the first number of RLC data packets, and the sequence numbers between these RLC data packets are arranged in sequence, thereby ensuring the sequential sending of the RLC data packets, avoiding the UE from being unable to decode due to receiving out-of-order RLC data packets, and further improving the UE's receiving performance.

Those skilled in the art will clearly understand that for the sake of convenience and brevity, the division of the above-mentioned functional units is only used as an example for illustration. In actual applications, the above-mentioned functions can be distributed and completed by different functional units as needed, that is, the internal structure of the device can be divided into different functional units to complete all or part of the functions described above. The specific working processes of the above-mentioned systems, devices, and units can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

The technical solution in the embodiment of the present invention is also applicable to the networking scenario between the first base stations and the networking scenario between the second base stations, that is, the embodiment of the present invention does not limit the base station form.

In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units or units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) or a processor to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

The above embodiments are merely used to provide a detailed introduction to the technical solutions of the present application. However, the description of the above embodiments is only intended to help understand the method and core concept of the present invention and should not be construed as limiting the present invention. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention.

Claims (33)

1. A method for offloading Radio Link Control (RLC) data packets, characterized in that it includes: The first base station receives an RLC data packet request message sent by the second base station. The RLC data packet request message is used by the second base station to request the first base station to send a first number of RLC data packets to the carrier aggregation CA user equipment (UE) through the secondary cell. The RLC data packet request message is sent by the second base station to the first base station at a first moment. The time difference between the first moment and the second moment is T, where T is greater than 2t. The second moment is the moment when the second base station sends the first number of RLC data packets to the UE. t is the one-way transmission delay between the second base station and the first base station. The first base station determines, based on the RLC data packet request message, the second number of RLC data packets that the first base station will send to the UE through the primary cell within a time period of T-t, wherein the start time of the T-t time period is the time when the first base station receives the RLC data packet request message; According to the sequence number of the RLC data packets to be sent from front to back, the first base station allocates the first second number of RLC data packets to the first base station from the RLC data packets to be sent, and allocates the first number of RLC data packets to the second base station starting from the first RLC data packet whose sequence number is after the first second number of RLC data packets; The first base station sends the first number of RLC data packets to the second base station. 2. The method as described in claim 1, characterized in that the method further comprises: The first base station sends the second number of RLC data packets to the UE through the main cell. 3. The method as described in claim 2, characterized in that the method further comprises: The first base station receives ACK/NACK information sent by the UE through the main cell. The ACK/NACK information includes feedback information from the UE for the first number of RLC data packets and feedback information from the UE for the second number of RLC data packets. 4. The method as described in claim 3, characterized in that, after the first base station receives the ACK/NACK information sent by the UE through the primary cell, the method further includes: If the feedback information received by the first base station for the first number of RLC data packets includes NACK, then the first base station determines whether the second base station can obtain HARQ merging gain by performing Hybrid Automatic Repeat Request (HARQ) on the RLC data packets corresponding to the NACK through the secondary cell. If HARQ combining gain can be obtained, the first base station sends the NACK to the second base station and instructs the second base station to retransmit the RLC data packet to the UE using HARQ. 5. The method as described in claim 4, wherein the first base station determines whether the second base station can obtain HARQ merging gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, specifically including: When the first base station determines that the number of HARQ processes currently used by the second base station on the secondary cell is less than the maximum number of HARQ processes, the first base station determines that the second base station can obtain HARQ merging gain by performing HARQ on the RLC data packets corresponding to the NACK through the secondary cell. 6. The method as described in claim 4 or 5, characterized in that the method further comprises: If the first base station determines that the second base station cannot obtain HARQ merging gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, then the first base station retransmits the RLC data packet corresponding to the NACK to the UE through the primary cell using the Automatic Repeat Request (ARQ) method. 7. The method as described in claim 6, characterized in that, before the first base station receives the ACK/NACK information sent by the UE through the primary cell, the method further includes: The first base station receives the RLC packet assembly result sent by the second base station. The RLC packet assembly result is used to indicate the information of the RLC data packets transmitted by the second base station to the UE through the secondary cell. The RLC data packets transmitted by the second base station to the UE through the secondary cell are part or all of the first number of RLC data packets. The first base station retransmits the RLC data packet corresponding to the NACK to the UE via the primary cell in ARQ mode, specifically including: Based on the RLC packet assembly result, the first base station retransmits the RLC data packet corresponding to the NACK to the UE via the primary cell in ARQ mode. 8. The method as described in claim 4 or 5, characterized in that the method further comprises: If the first base station determines that the second base station cannot obtain HARQ merging gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, the first base station sends the NACK to the second base station and instructs the second base station to retransmit the RLC data packet corresponding to the NACK to the UE through the secondary cell in ARQ mode. 9. A method for offloading Radio Link Control (RLC) data packets, characterized in that it includes: The second base station sends an RLC data packet request message to the first base station. The RLC data packet request message is used by the second base station to request the first base station to send a first number of RLC data packets to the carrier aggregation CA user equipment (UE) through the secondary cell. The RLC data packet request message is sent by the second base station to the first base station at a first moment. The time difference between the first moment and the second moment is T, where T is greater than 2t. The second moment is the moment when the second base station sends the first number of RLC data packets to the UE. t is the one-way transmission delay between the second base station and the first base station. The second base station receives the first number of RLC data packets sent by the first base station. The process of determining the first number of RLC data packets includes: according to the RLC data packet request message, the first base station determines the second number of RLC data packets sent by the first base station to the UE through the primary cell within a time period T-t, wherein the start time of the time period T-t is the time when the first base station receives the RLC data packet request message; the first base station allocates the first second number of RLC data packets from the RLC data packets to be sent in the order of their sequence numbers from front to back; and allocates the first number of RLC data packets to the second base station starting from the first RLC data packet whose sequence number is after the first second number of RLC data packets. 10. The method of claim 9, wherein the method further comprises: The second base station receives feedback information from the first base station regarding some or all of the first number of RLC data packets sent by the UE. The feedback information from the UE regarding the first number of RLC data packets is an ACK/NACK message sent by the UE to the first base station. The ACK/NACK message also includes feedback information from the UE regarding the second number of RLC data packets. 11. The method of claim 10, wherein before the second base station receives the feedback information from the first base station regarding the first number of RLC data packets sent by the UE, the method further comprises: The second base station sends an RLC packet assembly result to the first base station. The RLC packet assembly result is used to indicate the information of the RLC data packets transmitted by the second base station to the UE through the secondary cell. The RLC data packets transmitted by the second base station to the UE through the secondary cell are part or all of the first number of RLC data packets. 12. A base station for a first base station, characterized in that it comprises: The first receiving module is configured to receive a Radio Link Control (RLC) Data Packet Request message sent by the second base station. The RLC Data Packet Request message is used by the second base station to request the first base station to send a first number of RLC data packets to the carrier aggregation (CA) user equipment (UE) through the secondary cell. The RLC Data Packet Request message is sent by the second base station to the first base station at a first moment. The time difference between the first moment and the second moment is T, where T is greater than 2t. The second moment is the moment when the second base station sends the first number of RLC data packets to the UE. t is the one-way transmission delay between the second base station and the first base station. The determining module is configured to determine, based on the RLC data packet request message, a second number of RLC data packets sent by the first base station to the UE through the primary cell within a time period T-t, wherein the start time of the time period T-t is the time when the first base station receives the RLC data packet request message; The allocation module is configured to allocate the first second number of RLC data packets to the first base station from the RLC data packets to be sent in the order of their sequence numbers from front to back, and to allocate the first number of RLC data packets to the second base station starting from the first RLC data packet whose sequence number is located after the first second number of RLC data packets. The first sending module is used to send the first number of RLC data packets to the second base station. 13. The base station as claimed in claim 12, wherein the base station further comprises a second transmitting module, the second transmitting module being used for: The second number of RLC data packets are sent to the UE through the primary cell. 14. The base station as described in claim 13, wherein the base station further comprises a second receiving module, the second receiving module being used for: The primary cell receives ACK/NACK information sent by the UE, wherein the ACK/NACK information includes feedback information from the UE for the first number of RLC data packets and feedback information from the UE for the second number of RLC data packets. 15. The base station as described in claim 14, wherein the base station further comprises a judgment module, configured to: after the second receiving module receives the ACK/NACK information sent by the UE through the primary cell, if the feedback information for the first number of RLC data packets in the ACK/NACK information includes NACK, then determine whether the second base station can obtain HARQ merging gain by performing Hybrid Automatic Repeat Request (HARQ) on the RLC data packets corresponding to the NACK through the secondary cell; The first sending module is further configured to: if HARQ combining gain can be obtained, send the NACK to the second base station and instruct the second base station to retransmit the RLC data packet to the UE using HARQ. 16. The base station as described in claim 15, wherein the determining module is specifically used for: When it is determined that the number of HARQ processes currently used by the second base station on the secondary cell is less than the maximum number of HARQ processes, it is determined that the second base station can obtain HARQ merging gain by performing HARQ on the RLC data packets corresponding to the NACK through the secondary cell. 17. The base station as described in claim 15 or 16, wherein the base station further comprises a retransmission module, used for: If the determination module determines that the second base station cannot obtain HARQ merging gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, then it retransmits the RLC data packet corresponding to the NACK to the UE through the primary cell and via the second transmission module in the form of Automatic Repeat Request (ARQ). 18. The base station as described in claim 17, wherein the first receiving module is further configured to: Before the second receiving module receives the ACK/NACK information sent by the UE through the primary cell, it receives the RLC packet assembly result sent by the second base station. The RLC packet assembly result is used to indicate the information of the RLC data packets transmitted by the second base station to the UE through the secondary cell. The RLC data packets transmitted by the second base station to the UE through the secondary cell are part or all of the first number of RLC data packets. The retransmission module is specifically used to: retransmit the RLC data packet corresponding to the NACK to the UE in ARQ mode through the main cell and via the second transmission module, based on the RLC packet assembly result. 19. The base station as described in claim 15 or 16, wherein the first transmitting module is further configured to: If the determination module determines that the second base station cannot obtain HARQ merging gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, it sends the NACK to the second base station and instructs the second base station to retransmit the RLC data packet corresponding to the NACK to the UE through the secondary cell in ARQ mode. 20. A base station for use as a second base station, characterized in that it comprises: The first transmitting module is used to transmit a Radio Link Control (RLC) data packet request message to the first base station. The RLC data packet request message is used by the second base station to request the first base station to transmit a first number of RLC data packets to the carrier aggregation (CA) user equipment (UE) through the secondary cell. The RLC data packet request message is sent by the second base station to the first base station through the first transmitting module at a first moment. The time difference between the first moment and the second moment is T, where T is greater than 2t. The second moment is the moment when the second base station transmits the first number of RLC data packets to the UE through the second transmitting module. t is the one-way transmission delay between the second base station and the second base station. The first receiving module is configured to receive the first number of RLC data packets sent by the first base station. The process of determining the first number of RLC data packets includes: according to the RLC data packet request message, the first base station determines a second number of RLC data packets to be sent by the first base station to the UE through the primary cell within a time period T-t, wherein the start time of the time period T-t is the time when the first base station receives the RLC data packet request message; the first base station allocates the first second number of RLC data packets to the first base station from the RLC data packets to be sent in the order of their sequence numbers from front to back; and allocates the first number of RLC data packets to the second base station starting from the first RLC data packet whose sequence number is after the first second number of RLC data packets. 21. The base station as described in claim 20, wherein the first receiving module is further configured to: The system receives feedback information from the first base station regarding some or all of the first number of RLC data packets sent by the UE. The feedback information from the UE regarding the first number of RLC data packets is an ACK/NACK message sent by the UE to the first base station. The ACK/NACK message also includes feedback information from the UE regarding the second number of RLC data packets. 22. The base station as described in claim 21, wherein the first transmitting module is further configured to: Before the first receiving module receives the feedback information from the UE regarding the first number of RLC data packets sent by the first base station, the RLC packet assembly result is sent to the first base station. The RLC packet assembly result is used to indicate the information of the RLC data packets transmitted by the second base station to the UE through the secondary cell and the second sending module. The RLC data packets transmitted by the second base station to the UE through the secondary cell and the second sending module are part or all of the first number of RLC data packets. 23. A base station for a first base station, characterized in that it includes a memory, a processor, a computer program stored in the memory and executable on the processor, and an interface; The interface is used to receive a Radio Link Control (RLC) Data Packet Request message sent by a second base station. The RLC Data Packet Request message is used by the second base station to request a first number of RLC data packets to be sent by the second base station to the carrier aggregation (CA) user equipment (UE) through a secondary cell. The RLC Data Packet Request message is sent by the second base station to the first base station at a first moment. The time difference between the first moment and the second moment is T, where T is greater than 2t. The second moment is the moment when the second base station sends the first number of RLC data packets to the UE. t is the one-way transmission delay between the second base station and the first base station. The processor, when executing the program, performs the following steps: Based on the RLC data packet request message, determines a second number of RLC data packets that the first base station will send to the UE through the primary cell within a time period T-t, wherein the start time of the T-t time period is the time when the first base station receives the RLC data packet request message; and allocates the first second number of RLC data packets to the first base station from the RLC data packets to be sent in order of their sequence numbers from front to back, and allocates the first number of RLC data packets to the second base station starting from the first RLC data packet whose sequence number is after the first second number of RLC data packets. The processor is also configured to send the first number of RLC data packets to the second base station via the interface. 24. The base station as claimed in claim 23, wherein the base station further comprises a transceiver; the processor is further configured to: The second number of RLC data packets are sent to the UE via the main cell and the transceiver. 25. The base station as claimed in claim 24, wherein the transceiver is further configured to: The primary cell receives ACK/NACK information sent by the UE, wherein the ACK/NACK information includes feedback information from the UE for the first number of RLC data packets and feedback information from the UE for the second number of RLC data packets. 26. The base station as claimed in claim 25, wherein the processor is further configured to: After the transceiver receives the ACK/NACK information sent by the UE through the primary cell, if the feedback information for the first number of RLC data packets in the ACK/NACK information includes NACK, then it is determined whether the second base station can obtain HARQ merging gain by performing Hybrid Automatic Repeat Request (HARQ) on the RLC data packets corresponding to the NACK through the secondary cell; and if HARQ merging gain can be obtained, then the NACK is sent to the second base station through the interface, and the second base station is instructed to retransmit the RLC data packets to the UE using HARQ. 27. The base station as described in claim 26, wherein the processor is further configured to determine whether the second base station can obtain HARQ merging gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, specifically: When it is determined that the number of HARQ processes currently used by the second base station on the secondary cell is less than the maximum number of HARQ processes, it is determined that the second base station can obtain HARQ merging gain by performing HARQ on the RLC data packets corresponding to the NACK through the secondary cell. 28. The base station as described in claim 26 or 27, wherein the processor is further configured to: If it is determined that the second base station cannot obtain HARQ merging gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, then the base station retransmits the RLC data packet corresponding to the NACK to the UE through the primary cell and the transceiver in the Automatic Repeat Request (ARQ) manner. 29. The base station as claimed in claim 28, wherein the interface is further configured to: receive an RLC packet assembly result sent by the second base station before the transceiver receives ACK/NACK information sent by the UE through the primary cell, the RLC packet assembly result being used to indicate information of the RLC data packets transmitted by the second base station to the UE through the secondary cell; wherein the RLC data packets transmitted by the second base station to the UE through the secondary cell are part or all of the first number of RLC data packets; The processor is further configured to retransmit the RLC data packet corresponding to the NACK to the UE via the main cell and the transceiver in ARQ mode, specifically: based on the RLC packet assembly result, retransmit the RLC data packet corresponding to the NACK to the UE via the main cell and the transceiver in ARQ mode. 30. The base station as described in claim 26 or 27, wherein the processor is further configured to: If it is determined that the second base station cannot obtain HARQ merging gain by performing HARQ on the RLC data packet corresponding to the NACK through the secondary cell, then the NACK is sent to the second base station through the interface, and the second base station is instructed to retransmit the RLC data packet corresponding to the NACK to the UE through the secondary cell in ARQ mode. 31. A base station for a second base station, characterized in that it includes a memory, a processor, a computer program stored in the memory and executable on the processor, an interface, and a transceiver; The processor, when executing the program, performs the following steps: sending a Radio Link Control (RLC) data packet request message to the first base station through the interface, wherein the RLC data packet request message is used by the second base station to request the first base station to send a first number of RLC data packets to the carrier aggregation (CA) user equipment (UE) through the secondary cell, the RLC data packet request message is sent by the processor to the first base station through the interface at a first moment, the time difference between the first moment and the second moment is T, where T is greater than 2t, the second moment is the moment when the processor sends the first number of RLC data packets to the UE through the transceiver, and t is the one-way transmission delay between the second base station and the first base station; The interface is used to receive the first number of RLC data packets sent by the first base station. The process of determining the first number of RLC data packets includes: according to the RLC data packet request message, the first base station determines a second number of RLC data packets to be sent by the first base station to the UE through the primary cell within a time period T-t, wherein the start time of the time period T-t is the time when the first base station receives the RLC data packet request message; the first base station allocates the first second number of RLC data packets to the first base station from the RLC data packets to be sent in the order of their sequence numbers from front to back; and allocates the first number of RLC data packets to the second base station starting from the first RLC data packet whose sequence number is after the first second number of RLC data packets. 32. The base station as described in claim 31, wherein the interface is further configured to: The system receives feedback information from the first base station regarding some or all of the first number of RLC data packets sent by the UE. The feedback information from the UE regarding the first number of RLC data packets is an ACK/NACK message sent by the UE to the first base station. The ACK/NACK message also includes feedback information from the UE regarding the second number of RLC data packets. 33. The base station as described in claim 32, wherein the processor is further configured to: Before receiving feedback information from the UE regarding the first number of RLC data packets sent by the first base station at the interface, an RLC packet assembly result is sent to the first base station through the interface. The RLC packet assembly result is used to indicate the information of the RLC data packets transmitted by the processor to the UE through the secondary cell and the transceiver. The RLC data packets transmitted by the processor to the UE through the secondary cell and the transceiver are part or all of the first number of RLC data packets.