WO2018165864A1

WO2018165864A1 - Data transmission method, control plane device and base station

Info

Publication number: WO2018165864A1
Application number: PCT/CN2017/076645
Authority: WO
Inventors: 朱方园; 李岩; 倪慧; 李建
Original assignee: 华为技术有限公司
Priority date: 2017-03-14
Filing date: 2017-03-14
Publication date: 2018-09-20

Abstract

Provided are a data transmission method, a control plane device and a base station, wherein same can save on signalling resources for air interface transmission. The method in the present application comprises: after receiving downlink data to be sent to a UE, a control plane device sending, according to identifier information about a source base station in the context of the UE, a downlink message to the source base station; and then, if the control plane device receives, from the source base station, a first uplink message for indicating that the UE is not within a coverage range of the source base station, the control plane device determining a target base station currently serving the UE, and sending the downlink data to the UE by means of the target base station. In the present application, it is not necessary for a UE to send a null uplink packet to a core network every time a base station is replaced, and if the UE moves, a first uplink message can be sent when a source base station receives a downlink message, so that a control plane device redetermines a target base station where the UE is located. Therefore, the present application can save on signalling resources for air interface transmission on the basis of satisfying the mobility requirements of the UE.

Description

Data transmission method, control plane device and base station

Technical field

The present application relates to the field of communications, and in particular, to a data transmission method, a control plane device, and a base station.

Background technique

With the development of communication technology, the future is the world of Internet of Things, and the demand for equipment to equipment (M2M) is increasing. The future carrier business is no longer limited to voice and data traffic, but is considered. M2M connects to the business. Cellular-based Narrow Band Internet of Things (NB-IoT) technology can solve the M2M service problem of deep coverage, low transmission, low power consumption and large connection.

In order to meet massive fragmentation, low cost, low rate, low power consumption NB-IoT IoT applications, the core network supports the transmission of small data packets (referred to as small packets) services.

In the existing packet transmission scheme, the interface between the radio access network (RAN) and the core network is in a connectionless (ConnectionLess, CL) state, and the RAN does not save the context of the user equipment (User Equipment, UE). The core network holds the context of the UE. As shown in FIG. 1 , in the connectionless mode, if the UE moves in the range of the Tracking Area List (TA list) during the service, the coverage from the current base station is moved to the new base station. In the coverage, since the RAN does not have any context of the UE, the handover procedure of the UE in the connected state cannot be supported. In order to notify the User Plane (UP) device, the UE has moved to the coverage of the new base station, so that the current When the line data arrives, the UP can send the data packet of the UE to the new base station. Therefore, each time the UE replaces the base station, the UE needs to send an uplink null message to update the forwarding path of the downlink data stored in the UP, that is, update the UP. The identification information and address of the base station in the context of the stored UE. After receiving the uplink packet, the UP does not send it to the external data network, but discards it directly.

In the prior art solution, the UE needs to send an uplink null message to the core network every time the base station is replaced during the mobile process. Therefore, the signaling resources of the air interface transmission are wasted.

Summary of the invention

The embodiment of the invention provides a data transmission method, a control plane device and a base station, which can save signaling resources for air interface transmission.

A first aspect of the embodiments of the present invention provides a data transmission method, where the method includes:

After receiving the downlink data to be sent to the user equipment UE, the control plane device sends a downlink message to the source base station according to the context of the UE, where the context of the UE includes the identifier information of the source base station, and the control plane device receives the first uplink message from the source base station. The first uplink message is used to notify the control plane device that the UE is not in the coverage of the source base station. After that, the control plane device determines the identifier information of the target base station serving the UE, and sends the downlink data to the UE through the target base station.

In the embodiment of the present invention, the UE does not need to send an uplink null message to the core network to notify the current base station where the core network UE is located, but the downlink data of the UE arrives at the control plane. After the device, the control plane device sends a downlink message to the source base station. If the UE is not in coverage of the source base station, the source base station sends a first uplink message to notify the control plane device, and the control plane device re-determines the location of the UE. Target base station The target base station transmits downlink data to the UE. Therefore, the embodiment of the present invention can ensure that data is not lost when the UE moves, and can save signaling resources of air interface transmission on the basis of satisfying the mobility requirement of the UE.

Optionally, the downlink message sent by the control plane device to the source base station includes the received downlink data to be sent to the UE, that is, the downlink data is encapsulated in the downlink message and sent to the source base station; if the UE is not in the coverage of the source base station When the source base station fails to send the downlink data, the method further includes: the control plane device receives the downlink data from the source base station, and buffers the downlink data. Therefore, packet loss of downlink data can be avoided.

Optionally, the control plane device buffers the received downlink data to be sent to the UE, and the downlink information sent by the control plane device to the source base station does not include the downlink data, where the downlink message is used to confirm whether the UE is located in the coverage of the source base station. If the UE is located in the coverage of the source base station, the buffered downlink data is sent to the source base station. In this manner, it is possible to save signaling transmission in a unidirectional packet transmission scenario, for example, where the uplink data transmission is dominant and the downlink data transmission probability is extremely low.

Optionally, the downlink message sent by the control plane device to the source base station is a NAS message.

Optionally, the process of determining, by the control plane device, the identifier information of the target base station serving the UE is: the control plane device sends a paging message to the base station in the tracking area list where the UE is located, where the tracking area list includes the identifier information of the target base station; The device receives a paging response message from the target base station to determine identification information of the target base station.

This method is suitable for UEs that require high real-time downlink data. When the control plane device knows that the UE is not in the coverage of the source base station, it immediately pages the UE to determine the target base station, and sends the downlink data to the UE through the target base station. Therefore, the requirements of the UE with high requirements on the downlink data real-time performance can be satisfied.

Optionally, before the control plane device sends the paging message to the base station in the tracking area list where the UE is located, it is determined according to the context of the UE whether to immediately page the UE, and when it is determined that the paging is to be immediately performed, the UE is only sent to the UE. The base station in the tracking area list is sent a paging message.

Optionally, the control plane device determines to send a paging message to the base station in the tracking area list where the UE is located according to the subscription data of the UE or the service type of the UE in the context of the UE.

In this way, it is determined whether the UE is in a high-time manner for the downlink data according to the context of the UE, and if so, the paging is initiated, so that different processing can be performed according to the requirements of different UEs, and different UEs are required to perform downlink data. Real-time demand.

Optionally, the control plane device sends a paging message to other base stations except the source base station in the tracking area list where the UE is located, to save unnecessary signaling expenses.

Optionally, the manner in which the control plane device determines the target base station serving the UE further includes: the control plane device receives the second uplink message of the UE from the target base station, where the second uplink message includes the identifier information of the target base station and the first uplink data of the UE. Determining a target base station serving the UE according to the identification information of the target base station.

In this manner, the control plane device locally caches the downlink data of the UE, does not send a paging message, and waits for the UE to send the uplink packet, and then sends the buffered downlink data to the UE. For some UEs that have low real-time requirements for downlink data packets, paging signaling can be saved, which is beneficial to terminal power saving.

Optionally, the method further includes: before the control plane device receives the downlink data to be sent to the UE, the control plane device receives the third uplink data of the UE from the source base station, the control plane device starts a timer, and sets the state of the UE. a connection state; the control plane device sends a downlink message to the source base station according to the context of the UE, specifically: when the timer does not time out, The source base station sends a downlink message. The method further includes: after the control plane device receives the first uplink message from the source base station, setting the timer to a timeout, and updating the UE from the connected state to the idle state.

In this way, by setting a timer to maintain the state of the UE, after the control plane device receives the first uplink message and confirms that the UE is not in the coverage of the source base station, the timer is set to timeout, so that the state of the UE can be implemented. Before being updated to the connection state again, the downlink data of the subsequent arrival control plane device is prevented from being retransmitted to the source base station.

Optionally, in an implementation manner, the control plane device includes a mobility management device, and the method performed by the control plane device is performed by the mobility management device.

In a second aspect, an embodiment of the present invention provides a data transmission method, where the method includes:

The base station receives the downlink message sent by the control plane device to the user equipment UE; determines whether the UE is within the coverage of the base station; if the UE is not in the coverage of the base station, the base station sends a first uplink message to the control plane device, where the first uplink message is used. The notification control plane device UE is not within the coverage of the base station.

In the embodiment of the present invention, when the UE is moved and is not in the coverage of the base station, after receiving the downlink message sent by the control plane device, the base station sends a first uplink message to notify the control plane device, and the control plane device re- Determining the target base station where the UE is located, and transmitting downlink data to the UE through the target base station. Therefore, when the UE moves, the data is guaranteed to be free of packet loss, and the signaling resources of the air interface transmission can be saved on the basis of satisfying the mobility requirement of the UE.

Optionally, if the downlink message received by the base station includes the downlink data sent to the UE, the base station sends the downlink data to the control plane device to avoid packet loss of the downlink data.

In a third aspect, an embodiment of the present invention further provides a control plane device, which specifically implements a function corresponding to the data transmission method provided by the foregoing first aspect. The functions may be implemented by hardware or by executing corresponding software programs through hardware. The hardware and software include one or more unit modules corresponding to the functions described above, which may be software and/or hardware.

In a possible design, the control plane device comprises:

a receiving unit, configured to receive downlink data to be sent to the user equipment UE;

a sending unit, configured to send, by the receiving unit, the downlink message to the source base station according to the context of the UE, where the context of the UE includes the identifier information of the source base station;

The receiving unit is further configured to receive, by the source base station, a first uplink message, where the first uplink message is used to notify the control plane device that the UE is not in the coverage of the source base station;

The processing unit is configured to determine identity information of the target base station serving the UE, and send the downlink data to the UE by using the target base station.

In a possible design, the control plane device comprises:

Processor, memory and network interface;

The memory is used to store program code, and the processor calls the program code in the memory to perform the following operations:

Receiving, by the network interface, downlink data to be sent to the user equipment UE, and transmitting, by the network interface, a downlink message to the source base station according to the context of the UE, where the context of the UE includes the identifier information of the source base station; and then receiving the information from the source base station through the network interface. An uplink message is used to notify the control plane device that the UE is not in the coverage of the source base station; the identification information of the target base station serving the UE is determined, and the downlink data is sent to the UE by the target base station.

In a fourth aspect, the embodiment of the present invention further provides a base station, which specifically implements data corresponding to the foregoing second aspect. The function of the transfer method. The functions may be implemented by hardware or by executing corresponding software programs through hardware. The hardware and software include one or more unit modules corresponding to the functions described above, which may be software and/or hardware.

In a possible design, the base station includes:

a receiving unit, configured to receive a downlink message sent by the control plane device to the user equipment UE;

a processing unit, configured to determine whether the UE is within the coverage of the base station;

And a sending unit, configured to: when the processing unit determines that the UE is not in the coverage of the base station, send a first uplink message to the control plane device, where the first uplink message is used to notify the control plane device that the UE is not in the coverage of the base station.

In a possible design, the base station includes:

Interconnected processors, memories, receivers, and transmitters;

The memory is used to store program code, and the processor is used to call program code in the memory to perform the following operations:

Receiving, by the receiver, a downlink message sent by the control plane device to the user equipment UE; determining whether the UE is within the coverage of the base station; and when determining that the UE is not within the coverage of the base station, sending, by the transmitter, the first uplink message to the control plane device, The first uplink message is used to notify the control plane device that the UE is not within the coverage of the base station.

In a fifth aspect, the present application further provides a computer storage medium storing an application program, the program including some or all of the functions of the data transmission method provided by the above first aspect.

In a sixth aspect, the present application further provides a computer storage medium storing an application, the program including the method described in the above aspects.

In a seventh aspect, the present application also provides a computer program product comprising instructions which, when run on a computer, cause the computer to perform the methods described in the various aspects above.

It can be seen from the above technical solutions that the solution of the embodiment of the present invention has the following beneficial effects:

In the embodiment of the present invention, after receiving the downlink data to be sent to the UE, the control plane device sends a downlink message to the source base station according to the identity information of the source base station in the context of the UE, and then, if the control plane device receives the downlink message from the source base station, The first uplink message is used to indicate that the UE is not in the coverage of the source base station, and the control plane device determines the target base station of the currently serving UE, and sends the downlink data to the UE by using the target base station. Compared with the prior art, the UE sends an uplink null message to the core network every time the base station is replaced. The embodiment of the present invention can save the signaling resources of the air interface transmission on the basis of satisfying the mobility requirement of the UE.

DRAWINGS

1 is a schematic diagram of a UE transmitting an uplink null message to a core network in a mobile process in the prior art;

2 is a structural diagram of a next generation mobile network according to an embodiment of the present invention;

FIG. 3 is another structural diagram of a next generation mobile network according to an embodiment of the present invention; FIG.

4 is a flowchart of packet transmission in an embodiment of the present invention;

FIG. 5 is an information interaction diagram of a data transmission method according to an embodiment of the present invention; FIG.

6 is a schematic diagram of a data transmission process in an embodiment of the present invention;

FIG. 7 is a flow chart of information interaction of a data transmission process corresponding to FIG. 6 according to an embodiment of the present invention; FIG.

FIG. 8 is another schematic diagram of a data transmission process according to an embodiment of the present invention; FIG.

FIG. 9 is a flowchart of information interaction of a data transmission process corresponding to FIG. 8 according to an embodiment of the present invention; FIG.

FIG. 10 is another schematic diagram of a data transmission process according to an embodiment of the present invention; FIG.

FIG. 11 is a flow chart of information interaction of a data transmission process corresponding to FIG. 10 according to an embodiment of the present invention; FIG.

12 is a structural block diagram of a control plane device according to an embodiment of the present invention;

FIG. 13 is a schematic structural diagram of hardware of a control plane device according to an embodiment of the present invention; FIG.

14 is a structural block diagram of a base station in an embodiment of the present invention;

FIG. 15 is a schematic structural diagram of hardware of a base station according to an embodiment of the present invention.

detailed description

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

Embodiments of the present invention are applied to cellular-based narrowband Internet of Things (NB-IoT) data transmission. Among them, NB-IoT's main application scenarios include intelligent environment monitoring, smart city, smart meter reading, object tracking, smart farm/industry, smart home and other Internet of Things scenarios.

In order to meet massive fragmentation, low cost, low speed, low power consumption NB-IoT IoT applications, the core network transmits services through small packets (small packets).

Among them, the way of transmitting services through small packets is mainly applied to scenes such as sensors, measuring instruments, and meter reading. The service (packet service) transmitted by the packet is characterized in that the UE has a low packet transmission frequency and a small transmission data, and most of the services have low latency requirements, and there is no strict requirement for quality of service (QoS), and is not required. The core network maintains session continuity, and the core network can forward the packets sent by the UE "best effort" for such services. For example, some UEs (such as gas meters, water meters, metering reports for electric meters, smart agriculture or smart environment measuring instruments) are mainly reported above, with 1 to 4 reports per day, and 90% of cases with a payload of less than 10 bytes. Some UEs (such as smoke alarm detectors, smart meter power failure notifications) may receive uplink messages every few months or even annually.

The packet transmission method according to the embodiment of the present invention is based on a packet transmission scheme of a Non-Access Stratum (NAS), that is, the packet data is encapsulated in a NAS message, and the packet data is implemented by a Control Plane (CP). The transfer process.

The system architecture model of the NAS-based packet transmission scheme is the next-generation mobile network architecture diagram shown in Figure 2, including user equipment (UE), radio access network (RAN), control plane, user plane equipment, and external data network ( Network elements such as Data Network, DN).

Among them, the RAN is used to implement wireless related functions. The RAN is also called an access network (AN), and may specifically be a base station.

A base station as referred to in this application may refer to a device in an access network that communicates with a wireless terminal over one or more sectors over an air interface. It may be a narrow base station, that is, a public mobile communication base station, or a generalized base station, that is, a base station subsystem. For example, it may be a Global System for Mobile Communication (GSM) or a Base Transceiver Station (BTS) in Code Division Multiple Access (CDMA), or may be a wideband code division multiple access ( The base station (NodeB) in the Wideband Code Division Multiple Access (W-CDMA) may also be an evolved base station (NodeB or eNB or e-NodeB, evolutional Node B) in Long Term Evolution (LTE). Not limited.

The external data network may specifically be a server or a server cluster that provides services.

The UP has functions such as user packet forwarding, encapsulation, and statistics. The user plane is also called the user plane function entity (UP Function), or the user plane device.

The UE may include a handheld device having a wireless communication function, an in-vehicle device, a wearable device, a computing device, or other processing device connected to the wireless modem, and various forms of a mobile station (MS), a terminal, Terminal equipment and so on. For convenience of description, in the present application, it is simply referred to as a user equipment or a UE.

The control surface is also called the control surface function entity (CP Function), or the control plane device. In addition, as shown in FIG. 3, the control plane can be decomposed into a Mobility Management (MM) functional entity and a Session Management (SM) functional entity.

MM is responsible for user mobility management, including mobile state management, assigning user temporary identity, authenticating and authorizing users. The SM is responsible for UP network element selection, UP network element redirection, IP address allocation, and is responsible for the establishment, modification, and release of bearers, and QoS control.

The embodiment of the present invention introduces the solution in the embodiment of the present invention by taking the MM and SM separation architecture in the CP as an example. The MM and SM splicing architecture in the CP is similar to the implementation in the scheme, and is not described in detail.

Based on the architecture shown in FIG. 2, the process of NAS-based packet transmission will be described below with reference to FIG.

The embodiment of the present invention adopts a connection mode in which the RAN node is disconnected, that is, in the UE attaching process, the air interface does not initiate the establishment of a data radio bearer (DRB), and the subsequent message and data transmission adopt a signaling radio bearer ( Signal Radio Bearer (SRB) performs transmission without establishing a user plane tunnel between RAN and UP. Since the interface between the RAN and the core network has no connection and context, all subsequent NAS messages of the UE carry the UE identifier.

As shown in Figure 4:

401: The UE is attached to the network.

In the process of the UE attaching, the CP in the core network determines whether to establish a session context for the UE in the attaching process according to the subscription data of the UE or the information carried in the attach request of the UE (the capability information of the UE).

For a UE that can support multiple services, for example, the subscription data of the terminal indicates that the UE can send small packets and other services (such as accessing the network). If the UE does not explicitly indicate the type of service to be performed in the attach request, the control plane only determines whether the service to be performed by the UE is a packet service or a non-packet service, and the control plane may temporarily not create the UE. The session context does not assign an IP address to the UE. The subsequent UE may initiate a Protocol Data Unit (PDU) session establishment request process for a specific service before performing a specific service. The core network selects UP for the UE according to the specific request information of the UE, and allocates an IP address.

If the CP in the core network determines to establish a PDU session for the UE during the attach procedure, in addition to assigning a temporary identity to the UE, the UE is also selected to UP and assign an IP address.

402: The UE sends a NAS message to an access network RAN node (for example, a base station), where the NAS message carries an uplink data packet encrypted by the NAS, that is, carries the NAS PDU, and the NAS message further carries the temporary identifier of the UE and Information such as the name of the external data network (Data Network Name, DN name). The uplink data packet is also referred to as uplink data.

403: The RAN addresses the control plane CP of the core network that is currently serving the UE according to the temporary identifier of the UE, and sends the NAS message carrying the uplink data packet to the CP.

404: After receiving the packet, the control plane of the core network performs integrity check of the NAS PDU and decrypts the packet.

405: If the message sent by the UE is a non-IP packet, the CP checks whether the session context corresponding to the PDU has been created according to the context of the UE. If the CP has already created the session context, there is no need to create it. If there is no information about the session in the UE context stored by the CP, the CP will select an appropriate UP network element and assign an IP address to the UE. The UE does not participate in the session context creation process, and the IP address assigned by the CP is not sent. For the UE, the IP address is used only for the UP of the core network to encapsulate non-IP packets into IP packets and send them to the external data network.

406: The control plane sends the uplink data packet to the corresponding UP network element according to the context of the UE. The CP can maintain a transient relationship with the RAN to ensure that downlink data messages can be sent to the UE through the RAN node.

407: The user plane sends the PDU packet to the external data network. If the PDU message sent by the UE is a non-IP packet, the UP network element encapsulates the non-IP packet into an IP packet. The source IP address of the IP packet is the IP address allocated to the UE in step 405.

408: If the server of the external data network needs to return a downlink data packet (a downlink PDU, which may also be referred to as downlink data), it is sent to the user plane. For example, the downlink PDU may be a response message to the uplink data.

409: The user plane sends the received downlink data packet to the control plane. The user plane first determines whether to remove the IP header of the downlink data packet according to the context of the UE. For example, if the context corresponding to the packet is a non-IP (non-IP) type PDU session, the user plane network element first removes the IP header in the downlink data packet and sends it to the control plane. If the context corresponding to the packet is an IP type PDU session, the user plane does not perform any processing and directly sends it to the control plane. If the user does not have a session context of the UE, the UP directly discards the downlink data packet.

410: The control plane encrypts the packet and performs integrity protection, and then encapsulates the downlink data packet in the NAS message.

411: The control plane sends the downlink data packet encapsulated in the NAS message to the RAN node.

412: The RAN sends the received downlink data packet encapsulated in the NAS message to the UE.

As shown in FIG. 4, the UE transmits uplink data in a connectionless state, and the uplink data is encapsulated in a NAS message and transmitted to the external data network via the control plane CP. The CP maintains a transient relationship with the RAN, ensuring that downlink data can be sent to the UE through the RAN node.

The flow chart of the data transmission method in FIG. 5 is combined below. Figure 5 illustrates the processing flow of the CP for downlink data when the UE moves from the previous RAN (source base station) to another RAN (moves to the destination base station).

501. After receiving the downlink data to be sent to the UE, the control plane device sends a downlink message to the source base station according to the context of the UE.

When the external data network has downlink data to be sent to the UE, the external data network sends the downlink data to the CP through the UP. After receiving the downlink data to be sent to the UE, the CP obtains the identity information of the source base station from the context of the UE.

The CP sends downlink information to the source base station, and the source base station receives the downlink information sent by the CP.

Optionally, in an implementation manner, the downlink message includes downlink data that is sent by the CP to be sent to the UE. For example, the downlink data is sent to the source base station by encapsulating the downlink data in the downlink message.

Optionally, in another implementation manner, after receiving the downlink data to be sent to the UE, the CP caches the downlink data, and the downlink message sent by the CP to the source base station does not include the downlink data sent to the UE.

Specifically, the downlink message is a NAS message.

502. The source base station determines whether the UE is within the coverage of the source base station.

The specific method of determining is: if the source base station receives the downlink data sent by the CP (the downlink data is encapsulated in the NAS message), the base station attempts to send the downlink data to the UE, and if the sending fails, determines that the UE is not in the source base station. Coverage.

503. If the UE is not in the coverage of the source base station, the source base station sends a first uplink message to the control plane device.

If the source base station determines that the UE is not in its coverage, the source base station sends a first uplink message to the CP to notify the CP that the UE is not in the coverage of the source base station. The CP receives the first uplink message from the source base station, so that the UE has learned that the UE has moved, and is no longer in the coverage of the source base station.

If the downlink message received by the source base station encapsulates the downlink data to be sent to the UE, the source base station sends the downlink data to the CP. Optionally, the source base station may carry the downlink data in the first uplink message and send the downlink data to the CP.

Optionally, the first uplink message is a Downlink Data Notify (DDN) message.

504. The control plane device determines identification information of the target base station serving the UE.

After learning that the UE has moved and is no longer within the coverage of the source base station, the CP re-determines the target base station serving the UE. The manner of determining the target base station includes but is not limited to the following two types:

The first type: determining the target base station of the UE by paging the UE

The CP initiates paging to all the cells in the Tracking Area List (TA list) in which the UE is located according to the context of the UE, that is, sends a paging message to the base station in the TA list where the UE is located. After receiving the paging message, the target base station serving the UE sends a paging response message to the CP, and after receiving the paging response message, the CP determines the identification information of the target base station where the UE is currently located.

Optionally, the CP first determines, according to the context of the UE, whether to immediately send a paging message to the base station in the tracking area list where the UE is located, and sends a search to the base station in the TA list where the UE is located when determining that the paging is to be immediately performed. Call the message. For example, the CP may determine whether to send a paging message to the base station in the tracking area list where the UE is located, according to the subscription data of the UE or the service type of the UE in the context of the UE. For example, if the CP knows from the subscription information or service type of the UE that the UE has high real-time requirements for downlink data, the UE determines to immediately send a paging message to the base station in the TA list where the UE is located.

Optionally, the CP sends a paging message to all base stations except the source base station in the TA list to save unnecessary signaling expenses.

Second: the CP waits for the UE to send uplink data from the target base station to determine the target base station where the UE is located.

In this manner, the CP does not actively page the UE, but waits for the UE to send an uplink packet at the new location, and the base station (the target base station) where the UE is located sends the uplink packet (the second uplink message) to the CP. The second uplink message includes the identifier information of the target base station and the first uplink data of the UE. After receiving the second uplink message of the UE from the target base station, the CP determines the target base station of the serving UE according to the identity information of the target base station.

The method is applicable to the UE that is insensitive to the real-time performance of the downlink data. In this case, the CP first buffers the downlink data of the UE locally, and waits for the UE to send the uplink packet, and then sends the buffered downlink data to the UE.

For example, the CP may determine the target base station serving the UE by the second manner described above according to the configuration. In addition, the CP may first determine, according to the context of the UE, whether to immediately send a paging message to the base station in the tracking area list where the UE is located. For example, when the real-time requirement of the downlink data of the UE is higher than a preset value, the CP immediately sends a paging message to the base station in the tracking area list where the UE is located. When the real-time requirement of the downlink data of the UE is lower than a preset value, the CP determines the target base station serving the UE by using the foregoing second manner.

How the CP determines the target base station serving the UE will be further described in conjunction with FIGS. 6 through 11.

505. The control plane device sends the downlink data to the UE by using the target base station.

After re-determining the target base station serving the UE, the CP sends the downlink data to the UE through the target base station.

In the embodiment of the present invention, when the UE moves, it is not necessary to send an uplink null message to the core network every time the base station is replaced, to notify the current base station where the core network UE is located, and when the downlink data of the UE reaches the control plane. After the device, and the UE is in the connected state, the control plane device sends a downlink message to the source base station. If the UE moves and is not within the coverage of the source base station, the source base station sends a first uplink message to notify the control plane device, and the control plane device The target base station where the UE is located is determined, and the downlink data is sent to the UE through the target base station. Therefore, the embodiment of the present invention can meet the mobility requirement of the UE, that is, the data can be saved when the UE moves, and the uplink message is sent every time the UE replaces one base station. For the core network, the solution of the embodiment of the present invention can save signaling resources for air interface transmission.

Optionally, the CP maintains a Connected or Idle state of the UE by setting a timer. Before the step 501, that is, before the CP receives the downlink data to be sent to the UE, the CP receives the uplink data (the third uplink data) of the UE from the source base station, and the CP starts the timer, and sets the state of the UE to the connected state. The transient relationship between the CP and the RAN is maintained to ensure that when there is a downlink message, it can be sent to the UE through the RAN.

If the timer expires, the CP updates the connection state of the UE from the connection state to the idle state. When the downlink data of the UE arrives at the CP, the CP re-establishes the link with the target base station where the UE is located by paging or other means.

If the step 501 to step 503 are performed after the timer has not expired, after receiving the first uplink message from the source base station, the CP learns that the UE has moved and is not in the coverage of the source base station. In order to prevent the downlink data from being retransmitted to the source base station, the CP sets the timer to timeout and updates the UE from the connected state to the idle state. When the downlink data of the UE arrives at the CP, the CP buffers the downlink data until the CP determines the target base station of the serving UE through the step 504, and then sends the buffered downlink data to the UE through the target base station.

After receiving the downlink data to be sent to the UE from the CP, the downlink message sent to the source base station includes the implementation manner of the downlink data, and the implementation manner of not including the downlink data in the downlink message sent to the source base station, respectively. A data transmission method in an embodiment of the invention.

1. Downstream data is included in the downlink message.

The processing procedure of the downlink data included in the downlink message sent by the CP to the source base station is introduced in conjunction with FIG. 6 and FIG. 7 and FIG. 8 and FIG.

As shown in Figure 6, the UE has moved. For example, the UE moves from the coverage of the base station 1 to the coverage of the base station 2. After the UE moves, if the MM receives the downlink data to be sent to the UE from the SM and the UE is in the connected state (that is, the timer that the MM starts does not time out), the processing process of the MM for the downlink data is:

601. The MM directly encapsulates the downlink data (that is, the downlink data packet) in the NAS message and sends it to the UE. The RAN node (base station 1) stored in the text.

602. Because the UE has moved out of the coverage of the base station 1, the base station 1 fails to send the downlink data packet, and the base station 1 returns a downlink data packet and a DDN message to the MM to notify the core network that the UE has moved out of the coverage of the current base station. .

603. After receiving the DDN message, the MM caches the downlink data packet locally; and updates the state of the UE to the idle state (that is, the timer is set to timeout);

604. At the same time as or after performing step 603, the MM immediately initiates paging to all cells in the TA list where the UE is located. After receiving the paging message, the base station 2 of the serving UE sends a paging response message to the MM. After receiving the paging response message, the MM determines that the UE is located in the cell of the base station 2, and then the MM passes the buffered downlink through the base station 2. The data packet is sent to the UE.

In the embodiment shown in FIG. 6, after the MM learns that the UE moves, the MM decides to immediately page the UE. This method is suitable for UEs that require high real-time downlink data.

The specific flow of data transmission in the scenario shown in FIG. 6 will be described below with reference to FIG. 7.

701: The UE sends the NAS packet data in the connectionless mode. The specific process refers to FIG. 4. The base station where the UE is currently located is in a connectionless state, and the RAN node has no UE context and no UE identification information.

702: The MM receives the uplink data packet of the UE, and the MM starts a timer. The timer is used to maintain the state of the UE. When the downlink packet is delivered, the MM directly sends the NAS message before the timer expires. After the timer expires, the state of the UE in the core network is updated from the connection state to the idle state. The core network will use the paging procedure to trigger the state change of the UE.

703: The UE moves in the connected state, replaces the cell within the range of the TA list, and removes the coverage of the current base station. For example, the UE moves from the source base station to the target base station.

704: The external data network sends a downlink data (Downlink PDU) to the UP.

705: The UP sends the downlink data packet to the session management function SM entity according to the session context of the UE.

706: The SM entity sends the downlink data packet to the mobility management function MM entity according to the context information of the UE.

707: If the timer of the MM is not timed out, the MM performs encryption and integrity protection on the downlink data packet, and searches for a base station address saved in the UE context according to the context of the UE, where the base station is sent by the UE in a connected state. The base station (ie, the source base station) through which the uplink data message of the previous one is transmitted, that is, the latest location information of the UE saved by the core network.

708: The UE is in a connected state because the timer is not timed out, and the MM encapsulates the encrypted downlink data packet in the NAS message, and sends the downlink data packet to the source base station, and carries the ID of the UE.

709: The source base station fails to send the downlink data packet to the UE successfully because the UE moves, and the source base station fails to send the downlink data packet.

710: The source base station sends a downlink data notification (DDN) message to the MM, and returns the downlink data packet sent in step 708 to the MM to notify the MM that the UE has moved out of the current base station range, thereby triggering the MM to determine whether to perform paging.

711: Optionally, after receiving the downlink data notification message sent by the source base station, the MM returns an acknowledgement (ACK) message.

712: The MM updates the state of the session timer of the UE, sets the timeout, and the state of the UE in the core network. The MM then sends the downlink data packet to the source base station.

713: The MM caches the downlink data packet returned by the source base station locally, and determines whether the UE needs to be paged immediately according to the subscription data or the service type of the UE.

For example, for a UE with high real-time downlink data, you can choose to page immediately. The MM decides to page the UE immediately.

714: The MM initiates a paging process to the cell in the tracking area list where the UE is located according to the mobility management context of the UE: sending a paging message to the cell in the tracking area list where the UE is located, where the paging message carries the TA list, and the UE Information such as identity (ID) information, and paging priority indication (Paging Priority).

The failure of the previous source base station to send the downlink data indicates that the UE is not in the coverage of the source base station, so the MM may not send the paging message to the source base station to reduce the signaling burden of the air interface transmission.

715: After receiving the paging message sent by the core network, the base station (excluding the source base station) in the tracking area list (TA list) performs corresponding paging scheduling according to the paging priority indication carried in the paging message. And sending a paging message to the UE.

716: After receiving the paging message, the UE sends a paging response message to the current target base station, and carries the UE ID.

717: The RAN node (target base station) where the UE is currently located, after receiving the paging response message of the UE, sends a paging response message to the MM. The paging response message carries information about the target base station, for example, identifier information of the target base station and address information of the target base station.

718: After receiving the paging response message of the UE, the MM updates the current base station address of the UE stored in the context, and encapsulates the previously buffered downlink data packet in the NAS message to be sent to the target base station.

719: The target base station forwards the NAS message to the UE.

The flowchart shown in FIG. 7 is an example of the architecture in which the MM and the SM are separated as shown in FIG. 3 , and the embodiment of the present invention can also be applied to the architecture of the MM and the SM shown in FIG. 2 . . The specific process of data transmission in the architecture of the MM and the SM is also referred to FIG. 7. When the external data network sends the downlink data packet of the UE to the UP of the core network, the UP sends the packet according to the session context of the UE. Up to the CP, and then all the steps performed by the MM in FIG. 7 are performed by the CP, and no further description is made here.

In the embodiment shown in FIG. 6 and FIG. 7, the MM directly encapsulates the data packet in the NAS message and sends it to the source base station. If the UE moves and moves out of the coverage of the current base station, the source base station returns a DDN message to the control plane. And the downlink data packet, notifying the core network that the UE has moved out of the current base station range. After receiving the DDN message sent by the source base station, the MM updates the state of the UE in the core network, and the MM determines whether to page the UE immediately according to the subscription data and the service type of the UE. The embodiments of the present invention can meet the requirements of the UE with high requirements on the downlink data in real time, and can avoid packet loss in the downlink data, thereby satisfying the mobility requirement of the UE.

On the basis of this, the UE sends an uplink null message to the core network for each UE in the prior art. The solution of the embodiment of the present invention can also save signaling resources for air interface transmission.

The processing manner of another type of data transmission including downlink data in the downlink message sent by the MM to the source base station will be described below with reference to FIG. 8 and FIG.

In this embodiment, after the MM learns that the UE moves, the MM does not immediately page the UE, but caches the downlink data packet locally, and the UE actively sends an uplink data packet in the new location area to determine. UE's goal After the base station, the downlink data packet is sent to the UE. This method is applicable to UEs that do not require high-speed downlink data.

As shown in FIG. 8, the UE moves, and the coverage of the base station 1 is moved to the coverage of the base station 2. After the UE moves, if the MM receives the downlink data to be sent to the UE, the process of controlling the downlink data is controlled. for:

801. The MM directly encapsulates the downlink data packet in the NAS message and sends it to the RAN node (base station 1) stored in the UE context.

802. If the UE moves and moves out of the range of the current base station, the base station 1 fails to send the downlink data packet, and the base station 1 returns a downlink data packet and a downlink data notification (DDN) message to notify the core network that the UE has moved out of the current base station range.

803. After receiving the DDN message, the MM buffers the downlink data packet; and updates the state of the UE to the idle state (that is, the timer is set to timeout).

804. The MM waits for the UE to actively send an uplink data packet in the new location area, and the MM determines, by using the uplink data packet, that the UE is located in the base station 2.

805. The MM sends the buffered downlink data packet to the UE by using the base station 2.

The specific flow of data transmission in the scenario shown in FIG. 8 will be described in detail below with reference to FIG. 9.

Steps 901 to 911 are the same as steps 701 to 711 in the embodiment shown in FIG. 7, and refer to the embodiment shown in FIG.

912: The MM determines, according to the subscription data or service type of the UE, whether the UE needs to be paged immediately. For example, for the service of the UE that is insensitive to the downlink data time, the MM decides not to immediately page the packet, and first buffers the downlink data packet, thereby saving paging signaling between the core network and the terminal, which is beneficial to the terminal to save power.

913: The MM updates the state of the UE's timer, sets the timeout, and the UE updates the state of the core network from the Connected state to the Idle state.

914: The MM locally buffers downlink data packets of the UE.

915-916: If the MM continues to receive the downlink data packet of the UE, the MM continues to use the buffering method to prevent the downlink data packet from being sent to the source base station.

917: The UE actively initiates an uplink data packet in the new location area, and sends the uplink data packet to the core network through a NAS message. The method for transmitting the packet is described in the embodiment shown in FIG. The MM receives the uplink data packet from the base station (the target base station) where the UE is located, where the uplink data packet carries the identifier information of the target base station, and the MM determines the current location of the UE according to the identifier information of the target base station in the uplink data packet. The target base station where it is located.

Since the core network receives the uplink packet of the UE, the MM starts the timer, and the UE becomes the Connected state again.

918: The MM searches from the context whether the downlink data packet of the UE is buffered. If yes, the MM encrypts and protects the buffered downlink data packet, encapsulates it in the NAS message, and sends it to the target base station.

919: The target base station forwards the downlink packet to the UE.

Similarly, in the flowchart shown in FIG. 9 , the architecture in which the MM and the SM are separated as shown in FIG. 3 is taken as an example. In the embodiment of the present invention, the MM and the SM combined in FIG. 2 can also be applied. Architecture. For the specific process of data transmission in the MM and SM combined architecture, refer to FIG. 9. When the external data network sends the downlink data packet of the UE to the UP in the core network, the UP sends the packet to the UE according to the session context of the UE. CP, then executed by the CP All the steps performed by the MM in FIG. 9 are not described herein.

The difference between the embodiment shown in FIG. 8 and FIG. 9 and the embodiment shown in FIG. 6 and FIG. 7 is that the MM in the embodiment of the present invention adopts a data buffering method, and does not send a paging message, so that some downlink datagrams are sent. A UE with low real-time requirements can save paging signaling and save power for the terminal.

In the same manner, the embodiment of the present invention can avoid packet loss of downlink data, thereby satisfying the mobility requirement of the UE. On the basis of this, the UE sends an uplink null message to the core network for each UE in the prior art. The solution of the embodiment of the present invention can also save signaling resources for air interface transmission.

2. Downstream data is not included in the downlink message.

After receiving the downlink data to be sent to the UE from the MM, the MM first buffers the downlink data, and introduces an implementation manner in which the downlink message sent by the source base station does not include the downlink data.

In the embodiment of FIG. 6 to FIG. 9, when the MM receives the downlink data packet of the UE before the timer expires, the MM encrypts and protects the packet, and then directly encapsulates the packet into the NAS message and sends the packet to the RAN node. . If the RAN node that receives the message fails to send, the RAN node must return the message to the MM again, and then the MM determines whether it is necessary to page the UE to all the base stations in the tracking area list.

The method used in the embodiment of the present invention is: when the MM receives the downlink data packet of the UE before the timer expires, the MM does not directly send the downlink data to the RAN node, but directly caches it locally. First, the MM sends a downlink message to the RAN node, where the downlink message does not include downlink data, and the downlink message is used to enable the UE to return an ACK message, and is used to inform the RAN node whether the UE is located within the coverage of the RAN node. After the RAN node returns an ACK message and confirms that the UE has not moved, the MM encrypts and integrity protects the downlink message and sends it to the UE through the RAN node.

As shown in FIG. 10, if the UE moves and moves out of the coverage of the current base station, the base station 1 moves to the base station 2. After the UE moves, if the MM receives the downlink data to be sent to the UE, the control faces the downlink data. The process is:

1001, MM directly caches downlink data packets locally;

1002: The MM sends a NAS message that does not include a downlink data packet to the base station 1;

1003. The base station 1 fails to send a downlink data packet, and the base station 1 returns a downlink data notification (DDN) message to notify the core network that the UE has moved out of the current base station range.

1004. After receiving the DDN message, the MM determines whether to immediately page. If the page is immediately paged, it searches for the base station 2 where the UE is currently located. If not, the UE waits for the UE to actively send an uplink data in the new location area. At the time of the message, the base station 2 is determined again.

1005. The MM sends the buffered downlink data packet to the UE through the base station 2.

The MM timer is required to return the ACK message of the UE to confirm the location information of the UE. The embodiment of the present invention is applicable to a unidirectional packet transmission scenario, for example, the above. A scenario where the data transmission is dominant and the probability of downlink data transmission is extremely low.

The specific flow of data transmission in the scenario shown in FIG. 10 will be described in detail below with reference to FIG. 11.

Steps 1101 to 1106 are the same as steps 701 to 706 of the embodiment shown in FIG. 7, please refer to the embodiment shown in FIG.

1107: The MM temporarily buffers the downlink data packet locally because the timer does not time out, but the MM does not determine whether the UE has moved.

1108: The MM searches for the RAN node (source base station) information of the UE according to the context, and sends a NAS message to the source base station, where the NAS message does not carry the downlink packet data. The NAS message carries the identity of the UE, requesting the UE to return an acknowledgement (ACK) message. The source base station is a RAN node through which the UE transmits the previous uplink data, and is the latest location information of the UE stored in the context of the core network.

(1) If the UE does not remove the coverage of the source base station, the steps performed are steps 1109 to 1114:

1109: The source base station forwards the NAS message and sends it to the UE.

1110-1111: The UE receives the NAS message and returns an ACK message according to the indication in the NAS message. The source base station returns the ACK message to the MM.

1112-1113: After receiving the ACK message, the MM confirms that the UE is still in the coverage of the source base station, so the buffered downlink data packet is encrypted and integrity protected, encapsulated into the NAS message, and carries the UE ID, and sends To the source base station.

1114: The source base station sends the packet to the UE.

(2) If the UE has moved and the coverage of the target base station is removed, the steps performed are step 1115 to step 1120:

1115: After receiving the NAS message sent by the MM, the source base station sends the NAS message to the UE, and the failure occurs.

1116-1117: The source base station sends a DDN message to the MM to notify the MM that the UE is not in the coverage of the source base station. Optionally, the MM returns a response message after receiving the DDN message.

1118-1119: The MM determines whether to trigger immediate paging according to the subscription data and service type of the UE, and the MM sets the timer to timeout.

1120A: If the MM decides to immediately initiate paging to the UE according to the information in the context of the UE, the RAN node (target base station) where the UE is currently located is determined by paging, and the buffered downlink data is sent to the UE by the target base station. The specific process is the same as step 714 to step 719 in the embodiment shown in FIG. 7, and details are not described herein again.

1120B: If the MM decides not to page the UE immediately according to the information in the context of the UE, the downlink data of the subsequent UE is locally buffered, and the buffered downlink data packet is sent to the UE when the UE sends the uplink data. The specific process is the same as step 915 to step 919 in the embodiment shown in FIG. 9, and details are not described herein again.

Similarly, in the flowchart shown in FIG. 11 , the architecture in which the MM and the SM are separated as shown in FIG. 3 is taken as an example. In the embodiment of the present invention, the MM and the SM combined in FIG. 2 can also be applied. Architecture. The specific process of data transmission in the MM and SM combined architecture may also be referred to FIG. 11. When the external data network sends the downlink data packet of the UE to the UP in the core network, the UP sends the packet to the UE according to the session context of the UE. The CP, and then all the steps performed by the MM in FIG. 11 are performed by the CP, and will not be described here.

In the embodiment of the present invention, when the MM receives the downlink data packet of the UE before the timer expires, the downlink data packet is first cached in the MM, and the NAS message is sent to the RAN node, requesting the UE to return an ACK message. If the MM receives the ACK message returned by the UE, it indicates that the UE is not moving, and the MM sends the buffered downlink message to the UE. If the MM receives the DDN message returned by the source base station, it indicates that the UE has removed the coverage of the source base station, and then triggers the MM to re-determine the target base station where the UE is located, thereby preventing packet loss of the downlink data. Thereby enabling Enough to meet the mobility requirements of the UE. On the basis of this, the UE sends an uplink null message to the core network for each UE in the prior art. The solution of the embodiment of the present invention can also save signaling resources for air interface transmission.

The foregoing is a description of the data transmission method in the embodiment of the present invention. The control plane device and the base station in the embodiment of the present invention are introduced from the perspective of a functional module and a hardware implementation.

The control surface device in the embodiment of the present invention is a control surface (also referred to as a control surface functional entity) in the embodiment shown in FIG. 2 or FIG. 3. In a possible implementation manner, the control plane device in the embodiment of the present invention may be a 3GPP traditional Mobility Management Entity (MME). The control plane device may also be a CP that combines various control plane functions, and is specifically responsible for mobility management, authentication and authorization, session management, information storage, QoS control, charging, IP address allocation, and the like for the UE. In addition, the control plane device may also be an MM after the CP is separated into MM and SM, and is responsible for the mobility management of the user.

Specifically, FIG. 12 is a schematic structural diagram of a function module of a control plane device according to an embodiment of the present invention, including the following functional units:

The receiving unit 1201 is configured to receive downlink data to be sent to the UE.

The sending unit 1202 is configured to: after the receiving unit receives the downlink data, send a downlink message to the source base station according to the context of the UE, where the context of the UE includes the identifier information of the source base station;

The receiving unit 1201 is further configured to receive, by the source base station, a first uplink message, where the first uplink message is used to notify the control plane device that the UE is not in the coverage of the source base station;

The processing unit 1203 is configured to determine identifier information of the target base station serving the UE, and send the downlink data to the UE by using the target base station.

In some specific embodiments, the downlink message sent by the sending unit 1202 includes downlink data. The receiving unit 1201 is further configured to receive downlink data from the source base station. The control plane device further includes: a buffer unit 1204, configured to buffer downlink data.

In another specific embodiment, the control plane device further includes: a buffer unit, configured to buffer downlink data, and the downlink message sent by the sending unit 1202 does not include downlink data.

In some specific embodiments, the processing unit 1203 is configured to send, by using the sending unit 1202, a paging message to the base station in the tracking area list where the UE is located, where the tracking area list includes the identification information of the target base station, and the receiving unit 1201 A paging response message is received from the target base station to determine identification information of the target base station.

In some specific embodiments, the processing unit 1203 is specifically configured to determine, according to the context of the UE, whether to page the UE immediately. If it is determined that the UE is immediately paged, the sending unit 1202 sends the base station in the tracking area list where the UE is located. Sending a paging message, where the context of the UE includes the subscription data of the UE or the service type of the UE.

Optionally, the sending unit 1202 sends a paging message to the base station other than the source base station in the tracking area list where the UE is located, that is, the base station that receives the paging message does not include the source base station.

In some specific embodiments, the processing unit 1203 is configured to receive, by the receiving unit 1201, a second uplink message of the UE from the target base station, where the second uplink message includes the identifier information of the target base station and the first uplink data of the UE; The identification information of the target base station determines the target base station serving the UE.

In some specific embodiments, the receiving unit 1201 is further configured to: before receiving the downlink data to be sent to the UE, receive the third uplink data of the UE from the source base station; the processing unit 1203 is further configured to receive at the receiving unit 1201. To the third After the data is sent, the timer is started, and the state of the UE is set to the connection state. The sending unit 1202 is configured to send a downlink message to the source base station when the timer does not time out. The processing unit 1203 is further configured to: when the receiving unit 1201 After receiving the first uplink message, the source base station sets the timer to timeout and updates the UE from the connected state to the idle state.

For the information interaction between the units in the control plane device, refer to the foregoing method embodiment (the embodiment shown in FIG. 4 to FIG. 11), which is not described herein.

In practical applications, the hardware structure of the control plane device is relatively different due to different configurations or performances. As shown in FIG. 13, the control plane device may include one or more processors 1301, at least one memory 1302, and at least one network. Interface 1303. The memory 1302 is configured to store one or more operating systems and to store computer program code and data. The computer program code stored in memory 1302 may include one or more modules (not shown), each of which may include a series of instruction operations corresponding to the control plane device. The processor 1301 is in communication with the memory 1302, the network interface 1303, the control plane device communicates with other devices in the core network and the base station through the network interface 1303, and the processor 1301 executes a series of instruction operations in the memory 1302 on the control plane device to use All or part of the steps performed by the CP in the above method embodiment (the embodiment shown in FIGS. 4 to 11) are performed.

FIG. 14 is a schematic structural diagram of a function module of a base station according to an embodiment of the present invention, including the following functional units:

The receiving unit 1401 is configured to receive a downlink message that is sent by the control plane device to the user equipment UE.

The processing unit 1402 is configured to determine whether the UE is within the coverage of the source base station;

The sending unit 1403 is configured to: when the processing unit determines that the UE is not in the coverage of the source base station, send the first uplink message to the control plane device, where the first uplink message is used to notify the control plane device that the UE is not in the coverage of the source base station.

In some specific embodiments, the sending unit 1403 is further configured to: when the downlink message includes the downlink data sent to the UE, send the downlink data to the control plane device.

For the information interaction between the units in the base station in the embodiment shown in FIG. 14, refer to the steps performed by the base station in the foregoing method embodiment (the embodiment shown in FIG. 4 to FIG. 11), which is not described in this application. .

In a practical application, a base station provides UE-to-network wireless access, including one or more processors, one or more memories, one or more network interfaces, and one or more transceivers (each transceiver including receiving) Rx and transmitter Tx), these hardware modules are connected by a bus, and one or more transceivers are connected to an antenna or an antenna array. The network interface is connected to the core network through a link (eg, a link to the core network) or to other base stations via a wired or wireless link. The memory is for storing computer program code and data, and the processor executes a series of computer program code instructions in the memory to perform, in particular, all of the executions performed by the base station in the above-described method embodiments (the embodiments shown in FIGS. 4 to 11) Or part of the steps.

Further, the present application also provides a computer storage medium storing an application program which, when executed, includes some or all of the steps in the above data transmission method (the embodiment shown in FIGS. 4 to 11).

It should be noted that, in the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, it may be implemented in whole or in part in the form of a computer program product.

The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in accordance with embodiments of the present invention are generated in whole or in part. The computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer readable storage medium or transferred from one computer readable storage medium to another computer readable storage medium For example, the computer instructions can be from a website site, computer, server or data center via wired (eg, coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (eg, infrared, wireless, microwave, etc.) Another website site, computer, server, or data center for transmission. The computer readable storage medium can be any available media that can be stored by a computer or a data storage device such as a server, data center, or the like that includes one or more available media. The usable medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (such as a Solid State Disk (SSD)) or the like.

The terms "first", "second", "third", "fourth", etc. (if present) in the specification and claims of the present application and the above figures are used to distinguish similar objects, and are not necessarily used for Describe a specific order or order. It is to be understood that the data so used may be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than what is illustrated or described herein. In addition, the terms "comprises" and "comprises" and "the" and "the" are intended to cover a non-exclusive inclusion, for example, a process, method, system, product, or device that comprises a series of steps or units is not necessarily limited to Those steps or units may include other steps or units not explicitly listed or inherent to such processes, methods, products or devices.

In the above embodiments, the descriptions of the various embodiments are different, and the details that are not detailed in a certain embodiment can be referred to the related descriptions of other embodiments.

A person skilled in the art can clearly understand that for the convenience and brevity of the description, the specific working process of the system, the device and the unit described above can refer to the corresponding process in the foregoing method embodiment, and details are not described herein again.

In the several embodiments provided by the present application, it should be understood that the disclosed system, apparatus, and method may be implemented in other manners. For example, the device embodiments described above are merely illustrative. For example, the division of the unit is only a logical function division. In actual implementation, there may be another division manner, for example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be in an electrical, mechanical or other form.

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

In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a standalone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application can be embodied in the form of a software product stored in a storage medium, including a plurality of instructions for causing a computer device (which may be a personal computer, a server, Either a network device or the like) performs all or part of the steps of the method described in the various embodiments of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, and the like, which can store program codes. .

The principles and implementations of the present application are described in the following by using specific examples. The description of the above embodiments is only It is a method for helping to understand the present application and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope, in summary, The content of the present specification should not be construed as limiting the embodiments of the present application.

Claims

A data transmission method, comprising:

After receiving the downlink data to be sent to the user equipment UE, the control plane device sends a downlink message to the source base station according to the context of the UE, where the context of the UE includes the identifier information of the source base station;

The control plane device receives a first uplink message from the source base station, where the first uplink message is used to notify the control plane device that the UE is not in the coverage of the source base station;

The control plane device determines identification information of a target base station serving the UE, and sends the downlink data to the UE by using the target base station.
The method according to claim 1, wherein the downlink message includes the downlink data, and the method further includes:

The control plane device receives the downlink data from the source base station;

The control plane device buffers the downlink data.
The method of claim 1 further comprising:

The control plane device buffers the downlink data.
The method according to any one of claims 1 to 3, wherein the control plane device determines that the identity information of the target base station serving the UE comprises:

The control plane device sends a paging message to the base station in the tracking area list where the UE is located, where the tracking area list includes the identification information of the target base station;

The control plane device receives a paging response message from the target base station to determine identification information of the target base station.
The method according to claim 4, wherein the control plane device sends a paging message to the base station in the tracking area list where the UE is located, including:

The control plane device determines, according to the context of the UE, that the paging message is sent to a base station in a tracking area list where the UE is located, where the context of the UE includes subscription data of the UE or the UE Type of business.
The method according to claim 4 or 5, wherein the base station receiving the paging message does not include the source base station.
The method according to any one of claims 1 to 6, wherein the control plane device determines that the target base station serving the UE comprises:

The control plane device receives a second uplink message of the UE from the target base station, where the second uplink message includes identifier information of the target base station and first uplink data of the UE;

The control plane device determines, according to the identification information of the target base station, the target base station serving the UE.
The method according to any one of claims 1 to 7, wherein the method further comprises:

Before the control plane device receives the downlink data to be sent to the UE, the control plane device receives third uplink data of the UE from the source base station, and the control plane device starts a timer. And setting the state of the UE to a connected state;

The sending, by the control plane device, the downlink message to the source base station according to the context of the UE includes: when the timer does not time out, the control plane device sends the downlink message to the source base station;

After the control plane device receives the first uplink message from the source base station, the method further includes: The control plane device sets the timer to a timeout and updates the UE from a connected state to an idle state.
A method according to any one of claims 1 to 7, wherein

The control plane device includes a mobility management device.
A data transmission method, comprising:

The base station receives the downlink message from the control plane device;

Determining, by the base station, whether the user equipment UE is within the coverage of the base station;

If the UE is not in the coverage of the base station, the base station sends a first uplink message to the control plane device, where the first uplink message is used to notify the control plane device that the UE is not in the base station. Coverage.
The method of claim 9 wherein:

If the downlink message includes downlink data that is sent to the UE, the method further includes:

The base station sends the downlink data to the control plane device.
A control surface device, characterized in that the control surface device comprises:

a receiving unit, configured to receive downlink data to be sent to the user equipment UE;

a sending unit, configured to send, by the receiving unit, the downlink message to the source base station according to the context of the UE, where the context of the UE includes the identifier information of the source base station;

The receiving unit is further configured to receive, by the source base station, a first uplink message, where the first uplink message is used to notify the control plane device that the UE is not in a coverage range of the source base station;

And a processing unit, configured to determine identity information of the target base station serving the UE, and send the downlink data to the UE by using the target base station.
The control plane device according to claim 12, wherein the downlink message sent by the sending unit includes the downlink data;

The receiving unit is further configured to receive the downlink data from the source base station;

The control plane device further includes: a buffer unit, configured to cache the downlink data.
The control surface device according to claim 12, wherein the control surface device further comprises:

a cache unit, configured to cache the downlink data.
A control surface device according to any one of claims 12 to 14, wherein

The processing unit is configured to send, by using the sending unit, a paging message to a base station in a tracking area list where the UE is located, where the tracking area list includes identification information of the target base station; The unit receives a paging response message from the target base station to determine identification information of the target base station.
The control surface device according to claim 15, wherein

The processing unit is configured to: according to the context of the UE, determine, by using the sending unit, to send the paging message to a base station in a tracking area list where the UE is located, where the context of the UE includes the The subscription data of the UE or the service type of the UE.
The control plane device according to claim 15 or 16, wherein the base station receiving the paging message does not include the source base station.
A control surface device according to any one of claims 12 to 17, wherein

The processing unit is specifically configured to receive, by the receiving unit, a second uplink of the UE from the target base station And the second uplink message includes the identifier information of the target base station and the first uplink data of the UE; and the target base station serving the UE is determined according to the identifier information of the target base station.
A control surface device according to any one of claims 12 to 18, characterized in that

The receiving unit is further configured to: before receiving the downlink data to be sent to the UE, receive third uplink data of the UE from the source base station;

The processing unit is further configured to: after the receiving unit receives the third uplink data, start a timer, and set a state of the UE to a connected state;

The sending unit is specifically configured to: when the timer does not time out, send the downlink message to the source base station;

The processing unit is further configured to: after the receiving unit receives the first uplink message from the source base station, set the timer to a timeout, and update the UE from a connection state to an idle state.
A base station, the base station includes:

a receiving unit, configured to receive a downlink message from the control plane device;

a processing unit, configured to determine whether the user equipment UE is within the coverage of the base station;

a sending unit, configured to: when the processing unit determines that the UE is not in the coverage of the base station, send a first uplink message to the control plane device, where the first uplink message is used to notify the control plane device The UE is not within the coverage of the base station.
The base station according to claim 20, characterized in that:

The sending unit is further configured to send the downlink data to the control plane device when the downlink message includes downlink data sent to the UE.
A control surface device, characterized in that the control surface device comprises:

Processor, memory and network interface;

The memory is for storing computer program code, the processor invoking computer program code in memory to perform the following operations:

Receiving, by the network interface, the downlink data to be sent to the user equipment UE, and sending, by using the network interface, a downlink message to the source base station according to the context of the UE, where the context of the UE includes the identifier information of the source base station Receiving a first uplink message from the source base station by using the network interface, where the first uplink message is used to notify the control plane device that the UE is not in the coverage of the source base station; determining to serve the UE The identification information of the target base station, and the downlink data is sent to the UE by the target base station.
A base station, the base station includes:

Interconnected processors, memories, receivers, and transmitters;

The memory is for storing computer program code, the processor is for invoking computer program code in the memory to perform the following operations:

Receiving, by the receiver, a downlink message from the control plane device; determining whether the user equipment UE is within the coverage of the base station; and when determining that the UE is not within the coverage of the base station, using the transmitter to The control plane device sends a first uplink message, where the first uplink message is used to notify the control plane device that the UE is not in the coverage of the base station.
A computer readable storage medium comprising instructions that, when executed on a computer, cause the computer to execute The method of claims 1-9.
A computer program product comprising instructions which, when run on a computer, cause the computer to perform the method of any of claims 1-9.
A computer readable storage medium comprising instructions which, when executed on a computer, cause the computer to perform the method of claims 10-11.
A computer program product comprising instructions which, when run on a computer, cause the computer to perform the method of any of claims 10-11.