WO2020042040A1 - 一种下行数据早传方法及装置 - Google Patents

一种下行数据早传方法及装置 Download PDF

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Publication number
WO2020042040A1
WO2020042040A1 PCT/CN2018/103092 CN2018103092W WO2020042040A1 WO 2020042040 A1 WO2020042040 A1 WO 2020042040A1 CN 2018103092 W CN2018103092 W CN 2018103092W WO 2020042040 A1 WO2020042040 A1 WO 2020042040A1
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WIPO (PCT)
Prior art keywords
message
terminal
downlink data
network device
key
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PCT/CN2018/103092
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English (en)
French (fr)
Inventor
王宏
唐珣
于映辉
张戬
Original Assignee
华为技术有限公司
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Publication date
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to PCT/CN2018/103092 priority Critical patent/WO2020042040A1/zh
Priority to CN201880096908.3A priority patent/CN112640570B/zh
Priority to EP18931533.6A priority patent/EP3846577A4/en
Publication of WO2020042040A1 publication Critical patent/WO2020042040A1/zh
Priority to US17/186,026 priority patent/US20210195424A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W12/00—Security arrangements; Authentication; Protecting privacy or anonymity
    • H04W12/10—Integrity
    • H04W12/106—Packet or message integrity
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L63/00—Network architectures or network communication protocols for network security
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W12/00—Security arrangements; Authentication; Protecting privacy or anonymity
    • H04W12/03—Protecting confidentiality, e.g. by encryption
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W12/00—Security arrangements; Authentication; Protecting privacy or anonymity
    • H04W12/04—Key management, e.g. using generic bootstrapping architecture [GBA]
    • H04W12/041—Key generation or derivation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/02—Power saving arrangements
    • H04W52/0209—Power saving arrangements in terminal devices
    • H04W52/0212—Power saving arrangements in terminal devices managed by the network, e.g. network or access point is master and terminal is slave
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/02—Power saving arrangements
    • H04W52/0209—Power saving arrangements in terminal devices
    • H04W52/0212—Power saving arrangements in terminal devices managed by the network, e.g. network or access point is master and terminal is slave
    • H04W52/0216—Power saving arrangements in terminal devices managed by the network, e.g. network or access point is master and terminal is slave using a pre-established activity schedule, e.g. traffic indication frame
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W68/00—User notification, e.g. alerting and paging, for incoming communication, change of service or the like
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA
    • H04W74/0833—Random access procedures, e.g. with 4-step access
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/20—Manipulation of established connections
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/20—Manipulation of established connections
    • H04W76/27—Transitions between radio resource control [RRC] states
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/30—Connection release
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/02—Terminal devices
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/002—Transmission of channel access control information
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Definitions

  • the present application relates to the field of communication technologies, and in particular, to a method and a device for early transmission of downlink data.
  • a radio resource control (RRC) connection is not established between the base station and the terminal.
  • the terminal is in an idle state, which is the IDLE state.
  • RRC radio resource control
  • the network side initiates a paging to the terminal, establishes an RRC connection with the terminal, and the terminal enters the connected state from the idle state.
  • the process of the network side initiating a paging to the terminal and establishing an RRC connection requires the interaction of multiple signalings to complete.
  • the terminal When the terminal monitors the paging message and determines that the paging message carries its own identity, it triggers an RRC connection establishment process to complete the terminal's random access process. After the random access process is completed, the network side also needs to set the context of the terminal and configure the bearer of the terminal in order to send downlink data. It can be seen that when there is downlink data of the terminal on the network side, it needs to go through a very complicated process and requires a certain signaling overhead.
  • MTC machine type communication
  • NB-IoT narrow band Internet of Things
  • MTC-type terminals such as water meters and electricity meters
  • the signal coverage strength of the terminal cannot meet the requirements for signal reception. Therefore, MTC is enhanced to enable base stations and terminals to support extended coverage.
  • the main method of coverage is to repeatedly send uplink or downlink signals multiple times, and to achieve the purpose of improving the success rate of data reception through multiple receiving and combining. If the small data packet requires a high delay, the data transmission method and the repeated sending method cannot meet the small data packet's delay requirement.
  • the present application provides a method and a device for early transmission of downlink data, which are used to solve the problem of low resource utilization efficiency when transmitting downlink data packets with a small amount of data.
  • a method for early transmission of downlink data is provided.
  • the method may be executed by a terminal.
  • the method is implemented by the following steps: sending a random access preamble to a network device, and receiving a random access response from the network device,
  • a message 3 is sent to the network device, the message 3 carries a first indication, the first indication is used to indicate a single downlink data packet, and the message 4 is received from the network device, so
  • the message 4 carries downlink data.
  • sending an instruction from the terminal to the network device enables the network device to send a single downlink data to the terminal in the random access process according to the instruction sent by the terminal, without establishing the RRC connection of the terminal, so that the terminal can be idle. After receiving the downlink data, this helps reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • the first indication may also be used to indicate early transmission of downlink data; or the first indication may also be used to indicate that the downlink data of the terminal can be transmitted at one time; or the first indication may also be used to indicate the terminal No uplink response message or uplink data is sent after receiving the downlink data; or the first indication may also be used to instruct the terminal to release the connection after receiving the downlink data.
  • the message 3 is a first RRC message for requesting restoration of an RRC connection.
  • the message 4 is a second RRC message for instructing to release the RRC connection.
  • the method may also include implementations of integrity protection and encryption and decryption.
  • the context information is recovered, and the context information includes a first next hop chain count NCC, the first NCC is used to derive a first key, and the first key is used to decrypt the downlink data.
  • the first NCC is also used to derive a second key, and the second key is used to perform integrity protection check on the message 4.
  • the method for protecting the integrity of the message 4 in this design may be an independent design of the present application, or may be combined with the previous possible design to encrypt the downlink data to form a solution.
  • the first NCC can also be used to derive a second key and a fourth key
  • the second key can be used to perform integrity protection check on the message 4
  • the fourth key can be used
  • the message 4 is decrypted.
  • the method for protecting the integrity of the message 4 in this design may be an independent design of the present application, or may be combined with the previous possible design to encrypt the downlink data to form a solution.
  • the context information further includes a third key, and the third key is used to perform integrity protection check on the message 4.
  • the method for protecting the integrity of the message 4 in this design may be an independent design of the present application, or may be combined with the previous possible design to use a first key to decrypt the downlink data to form a scheme.
  • the context information further includes bearer configuration information and security configuration information.
  • the message 4 includes a second NCC
  • a solution of encryption and decryption and integrity protection can also be implemented by the following method: using the second NCC to derive a fifth key, and using the fifth key Decrypt the downlink data.
  • the second NCC can also be used to derive a sixth key, and the sixth key can be used to perform integrity protection check on the message 4.
  • the first key included in the context information can also be used.
  • Three keys perform integrity protection on the message 4.
  • the two methods for protecting the integrity of the message 4 in this design may both be independent designs of this application, or may be combined with the previous possible design to use a fifth key to decrypt the downlink data to form a scheme.
  • the message 4 can be prevented from being tampered with, and the security of the downlink data can be guaranteed.
  • a second indication may also be received from the network device, where the second indication is used to indicate a single downlink data packet.
  • a paging message may be received from the network device, where the paging message carries the second indication, and the paging message is used to page the terminal.
  • a permission indication may also be received from the network device, where the permission indication is used to instruct the network device to allow early transmission of downlink data.
  • a method for early transmission of downlink data is provided.
  • the method may be executed by a terminal.
  • the method is implemented by the following steps: sending a random access preamble to a network device, and receiving a random access response from the network device,
  • a message 3 is sent to the network device, the message 3 carries a first indication, the first indication is used to indicate a single downlink data packet, and the message 4 is received from the network device, so
  • the message 4 is an RRC message, and the RRC message includes downlink data of the terminal.
  • sending an instruction from the terminal to the network device enables the network device to send a single downlink data to the terminal in the random access process according to the instruction sent by the terminal, without establishing the RRC connection of the terminal, so that the terminal can be idle. After receiving the downlink data, this helps reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • the message 3 is an RRC data early transmission request message
  • the message 4 is an RRC data early transmission completion message
  • the message 3 is an RRC connection request message
  • the message 4 is RRC data Early transmission completion message
  • message 3 is an RRC connection request message
  • message 4 is an RRC connection release message
  • a method for early transmission of downlink data may be implemented by a network device, which is referred to herein as a first network device.
  • the method is implemented by the following steps: the first network device receives a random access preamble from a terminal The first network device sends a random access response to the terminal, the first network device receives a message 3 from the terminal, the message 3 carries a first instruction, and the first instruction is used to indicate the In a single downlink data packet, the first network device sends a message 4 to the terminal, and the message 4 carries downlink data.
  • the network device can send a single downlink data to the terminal during the random access process according to the instruction sent by the terminal, without establishing the RRC connection of the terminal, so that the terminal can receive the downlink data in the idle state, which helps Reduce resource consumption, reduce signaling overhead, and reduce terminal power consumption.
  • the first indication may also be used to indicate early transmission of downlink data; or the first indication may also be used to indicate that the downlink data of the terminal can be transmitted at one time; or the first indication may also be used to indicate the terminal No uplink response message or uplink data is sent after receiving the downlink data; or the first indication may also be used to instruct the terminal to release the connection after receiving the downlink data.
  • the message 3 is a first RRC message for requesting restoration of an RRC connection.
  • the message 4 is a second RRC message for instructing to release the RRC connection.
  • the method may also include implementations of integrity protection and encryption and decryption.
  • the first network device recovers the context information of the terminal, where the context information includes a first next hop chain count NCC, and the first NCC is used to derive a first key; the first network device Encrypt the downlink data using the first key.
  • the context information further includes a third key, and the first network device uses the third key to perform integrity protection on the message 4; or the first network device uses The first NCC derives a second key, and the first network device uses the second key to perform integrity protection on message 4; or, the first network device uses the first NCC to derive a second secret And a fourth key, use the second key to perform integrity protection on the message 4, and use the fourth key to encrypt the message 4.
  • three methods for integrity protection of message 4 are included. The three methods can be independent designs of this application, or they can use the first key to encrypt the downlink data in the previous possible design.
  • the scheme combination forms a scheme.
  • the message 4 carries a second NCC
  • a solution of encryption and decryption and integrity protection can also be implemented by the following method: the first network device uses the second NCC to derive a fifth key, and uses The fifth key encrypts the downlink data.
  • the first network device uses the second NCC to derive a sixth key, and uses the sixth key to perform integrity protection on the message 4; or, the first network device Restore the context information of the terminal, where the context information includes a third key, and use the third key to perform integrity protection on the message 4.
  • the two methods for protecting the integrity of the message 4 in this design may both be independent designs of this application, or may be combined with the previous possible design to use a fifth key to encrypt the downlink data to form a scheme.
  • the message 4 can be prevented from being tampered with, and the security of the downlink data can be guaranteed.
  • the first network device may further send a second instruction to the terminal, where the second instruction is used to indicate a single downlink data packet.
  • the first network device may send a paging message to the terminal, where the paging message carries a second indication.
  • the first network device receives a third instruction from the second network device, and the third instruction is used to indicate a single downlink data packet. Specifically, the first network device receives a paging message from the second network device, and the paging message carries the third indication.
  • the first network device receives a fourth instruction from a third network device, and the fourth instruction is used to indicate a single downlink data packet.
  • the first network device receives downlink data from a third network device, and the downlink data carries a fourth instruction, where the fourth instruction is used to indicate a single downlink data packet.
  • a method for early transmission of downlink data may be performed by a network device, which is referred to herein as a first network device.
  • the method is implemented by the following steps: a first network device receives a page from a second network device Message, the paging message carries a first indication, the first indication is used to indicate a single downlink data packet; the first network device receives a random access preamble from a terminal; and the first network device sends the The terminal sends a random access response; the first network device receives a message 3 from the terminal; the first network device sends a message 4 to the terminal, the message 4 is an RRC message, and the RRC message includes all The downlink data of the terminal is described.
  • the first network device may send a single downlink data to the terminal in a random access process according to an instruction sent by the terminal and the core network device without establishing an RRC connection of the terminal, so that the terminal can receive the downlink data in the idle state. This helps reduce resource consumption, reduce signaling overhead, and reduce terminal power consumption.
  • the first indication may also be used to indicate early transmission of downlink data; or the first indication may also be used to indicate that the downlink data of the terminal can be transmitted at one time; or the first indication may also be used to indicate the terminal No uplink response message or uplink data is sent after receiving the downlink data; or the first indication may also be used to instruct the terminal to release the connection after receiving the downlink data.
  • the message 3 is used to request the restoration of the RRC connection
  • the message 4 is used to instruct the terminal to release the RRC connection.
  • the method may also include implementations of integrity protection and encryption and decryption.
  • the first network device recovers the context information of the terminal, where the context information includes a first next hop chain count NCC, and the first NCC is used to derive a first key; the first network device Encrypt the downlink data using the first key.
  • the context information further includes a third key, and the first network device uses the third key to perform integrity protection on the message 4; or the first network device uses The first NCC derives a second key, and the first network device uses the second key to perform integrity protection on message 4; or, the first network device uses the first NCC to derive a second secret And a fourth key, use the second key to perform integrity protection on the message 4, and use the fourth key to encrypt the message 4.
  • three methods for integrity protection of message 4 are included. The three methods can be independent designs of this application, or they can use the first key to encrypt the downlink data in the previous possible design.
  • the scheme combination forms a scheme.
  • the message 4 carries a second NCC
  • a solution of encryption and decryption and integrity protection can also be implemented by the following method: the first network device uses the second NCC to derive a fifth key, and uses The fifth key encrypts the downlink data.
  • the first network device uses the second NCC to derive a sixth key, and uses the sixth key to perform integrity protection on the message 4; or, the first network device Restore the context information of the terminal, where the context information includes a third key, and use the third key to perform integrity protection on the message 4.
  • the two methods for protecting the integrity of the message 4 in this design may both be independent designs of this application, or may be combined with the previous possible design to use a fifth key to encrypt the downlink data to form a scheme.
  • the message 4 can be prevented from being tampered with, and the security of the downlink data can be guaranteed.
  • the first network device sends a second instruction to the terminal, where the second instruction is used to indicate a single downlink data packet.
  • the first network device may send a paging message to the terminal, where the paging message carries a second indication.
  • the first network device receives a third instruction from the terminal, and the third instruction is used to indicate a single downlink data packet.
  • the first network device receives a fourth instruction from a third network device, and the fourth instruction is used to indicate a single downlink data packet.
  • the first network device receives downlink data from a third network device, and the downlink data carries a fourth instruction, where the fourth instruction is used to indicate a single downlink data packet.
  • a method for early transmission of downlink data may be a network device, which is described here as a first network device.
  • the method is implemented by the following steps: the first network device receives a random access preamble from a terminal The first network device sends a random access response to the terminal; the first network device receives a first instruction from the terminal, the first instruction is used to indicate a single downlink data packet; the first network The device sends a message 4 to the terminal, where the message 4 is an RRC message, and the RRC message includes downlink data of the terminal.
  • the network device can send a single downlink data to the terminal during the random access process according to the instruction sent by the terminal, without establishing the RRC connection of the terminal, so that the terminal can receive the downlink data in the idle state, which helps Reduce resource consumption, reduce signaling overhead, and reduce terminal power consumption.
  • the first indication may also be used to indicate early transmission of downlink data; or the first indication may also be used to indicate that the downlink data of the terminal can be transmitted at one time; or the first indication may also be used to indicate the terminal No uplink response message or uplink data is sent after receiving the downlink data; or the first indication may also be used to instruct the terminal to release the connection after receiving the downlink data.
  • the message 3 is an RRC data early transmission request message
  • the message 4 is an RRC data early transmission completion message
  • the message 3 is an RRC connection request message
  • the message 4 is RRC data Early transmission completion message
  • message 3 is an RRC connection request message
  • message 4 is an RRC connection release message
  • the first network device sends a second instruction to the terminal, where the second instruction is used to indicate a single downlink data packet.
  • the first network device receives a third instruction from the second network device, and the third instruction is used to indicate a single downlink data packet.
  • the third indication is carried in a paging message, or the third indication is carried in a NAS message.
  • the first network device receives the downlink data from a second network device.
  • the downlink data is carried in a NAS message.
  • a method for early transmission of downlink data may be a core network device, which is referred to herein as a first core network device.
  • the method is implemented by the following steps: the first core network device is from an access network device Receiving a terminal initialization message, where the terminal initialization message carries a first instruction, where the first instruction is used to indicate a single downlink data packet; the first core network device receives a downlink of the terminal from a second core network device Data; the first core network device sends a NAS message to the access network device, and the NAS message carries downlink data of the terminal.
  • the first core network device can encapsulate the downlink data of the terminal in a NAS message and send it to the terminal via the access network device according to the instruction sent by the terminal. There is no need to establish the RRC connection of the terminal, so that the terminal can receive it in idle state Downlink data, which helps reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • the first core network device receives a second instruction from a second core network device, and the second instruction is used to indicate a single downlink data packet.
  • the first core network device receives a downlink data notification message from a second core network device, and the downlink data notification message carries the first indication.
  • the downlink data of the terminal carries a second indication, and the second indication is used to indicate a single downlink data packet.
  • a method for early transmission of downlink data may be a core network device, which is referred to herein as a first core network device.
  • the method is implemented by the following steps: the first core network device is from the second core network.
  • the device receives a first instruction, where the first instruction is used to indicate a single downlink data packet;
  • the first core network device receives downlink data of the terminal from the second core network device;
  • the first core network sends a NAS message to the access network device, and the NAS message carries downlink data of the terminal.
  • the first core network device may also receive instructions from other core network devices, and according to the instructions, the downlink data of the terminal is encapsulated in a NAS message and sent to the terminal via the access network device. There is no need to establish an RRC connection of the terminal, so that the terminal is idle.
  • the downlink data can be received, which helps reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • the first core network device receives a downlink data notification message from a second core network device, and the downlink data notification message carries the first indication.
  • the first core network device sends a second instruction to the access network device, where the second instruction is used to indicate a single downlink data packet.
  • the first core network device sends a paging message to the access network device, and the paging message carries the second indication.
  • the first core network device receives downlink data of the terminal from a second core network device, and the downlink data of the terminal carries the first instruction.
  • the NAS message further carries a second indication, where the second indication is used to indicate a single downlink data packet.
  • an apparatus for early transmission of downlink data which has an implementation of terminal device behavior in any one of the first aspect, the second aspect, and the first aspect or the second aspect.
  • a function which includes means corresponding to the steps or functions described in the above method aspect.
  • the steps or functions may be implemented by software, or by hardware (such as a circuit), or by a combination of hardware and software.
  • the above device includes one or more processors and a communication unit.
  • the one or more processors are configured to support the downlink data early transmission device to perform a corresponding function of the terminal in the foregoing method. For example, a random access preamble is sent to a network device, a random access response is received from the network device, a message 3 is sent to the network device, a first indication is carried in the message 3, and a message 4 is received from the network device.
  • the communication unit is configured to support the downlink data early transmission device to communicate with other devices to implement a receiving and / or transmitting function. For example, send each message and receive each message.
  • the device may further include one or more memories, and the memory is configured to be coupled to the processor, and stores the program instructions and / or data necessary for the device.
  • the one or more memories may be integrated with the processor, or may be separately provided from the processor. This application is not limited.
  • the communication unit may be a transceiver, or a transceiver circuit.
  • the transceiver may be an input / output circuit or an interface.
  • the device may also be a communication chip.
  • the communication unit may be an input / output circuit or an interface of a communication chip.
  • the foregoing downlink data early transmission device includes a transceiver, a processor, and a memory.
  • the processor is used to control the transceiver or the input / output circuit to send and receive signals
  • the memory is used to store a computer program
  • the processor is used to run the computer program in the memory, so that the device executes the first aspect, the second aspect, and the first aspect
  • an apparatus for early transmission of downlink data which has any one of the possible designs of the third aspect, the fourth aspect, the fifth aspect, and the third aspect, the possible design of any of the fourth aspect, or
  • the function of the network device behavior in any possible design of the fifth aspect which includes means corresponding to the steps or functions described in the above method aspect.
  • the steps or functions may be implemented by software, or by hardware (such as a circuit), or by a combination of hardware and software.
  • the foregoing downlink data early transmission device includes one or more processors and a communication unit.
  • the one or more processors are configured to support the downlink data early transmission device to execute any one of the third aspect, the fourth aspect, the fifth aspect, the third aspect, the possible design, and any of the fourth aspect.
  • the communication unit is configured to support the downlink data early transmission device to communicate with other devices to implement a receiving and / or transmitting function. For example, receiving an instruction and sending downlink data.
  • the apparatus may further include one or more memories, where the memories are configured to be coupled to the processor, and store the program instructions and / or data necessary for the network device.
  • the one or more memories may be integrated with the processor, or may be separately provided from the processor. This application is not limited.
  • the downlink data early transmission device may be a base station, gNB, or TRP, and the like, and the communication unit may be a transceiver or a transceiver circuit.
  • the transceiver may be an input / output circuit or an interface.
  • the device may also be a communication chip.
  • the communication unit may be an input / output circuit or an interface of a communication chip.
  • the foregoing downlink data early transmission device includes a transceiver, a processor, and a memory.
  • the processor is used to control the transceiver or the input / output circuit to send and receive signals
  • the memory is used to store a computer program
  • the processor is used to run the computer program in the memory, so that the device executes the third aspect, the fourth aspect, and the fifth aspect described above Any one of the possible designs in the third aspect, any of the possible designs in the fourth aspect, or the method for completing the network device in any of the possible designs in the fifth aspect.
  • an apparatus for early transmission of downlink data which has a core network device behavior in implementing any one of the possible designs of the sixth aspect, the seventh aspect, and the sixth aspect, or any one of the seventh aspect.
  • Functions which include means corresponding to the steps or functions described in the above method aspects.
  • the steps or functions may be implemented by software, or by hardware (such as a circuit), or by a combination of hardware and software.
  • the foregoing downlink data early transmission device includes one or more processors and a communication unit.
  • the one or more processors are configured to support the downlink data early transmission device to execute any one of the foregoing sixth aspect, the seventh aspect, the sixth aspect or any possible design of the seventh aspect Corresponding functions of network equipment. For example, an instruction is received from an access network device, downlink data is received from another core network device, and the downlink data is carried and sent to the access network device in a NAS message.
  • the communication unit is configured to support the downlink data early transmission device to communicate with other devices to implement a receiving and / or transmitting function. For example, receiving an instruction and sending downlink data.
  • the downlink data early transmission device may further include one or more memories, where the memories are configured to be coupled to the processor and store program instructions and / or data necessary for the network device.
  • the one or more memories may be integrated with the processor, or may be separately provided from the processor. This application is not limited.
  • the downlink data early transmission device may be an MME or the like, and the communication unit may be a transceiver or a transceiver circuit.
  • the transceiver may be an input / output circuit or an interface.
  • the device may also be a communication chip.
  • the communication unit may be an input / output circuit or an interface of a communication chip.
  • the foregoing downlink data early transmission device includes a transceiver, a processor, and a memory.
  • the processor is used to control the transceiver or the input / output circuit to send and receive signals
  • the memory is used to store a computer program
  • the processor is used to run the computer program in the memory, so that the device executes the sixth aspect, the seventh aspect, and the sixth aspect described above
  • a system which includes the downlink data early transmission device provided by at least two of the eighth aspect, the ninth aspect, or the tenth aspect described above.
  • a computer-readable storage medium for storing a computer program, the computer program including any one of the first aspect, the second aspect, and the first aspect, or the second aspect. Instructions in any of the possible designs.
  • a computer-readable storage medium for storing a computer program.
  • the computer program includes a possible design for implementing any one of the third aspect, the fourth aspect, the fifth aspect, and the third aspect. 2. Instructions for any one of the possible designs in the fourth aspect or the method in any of the possible designs for the fifth aspect.
  • a computer-readable storage medium for storing a computer program, the computer program including a possible design or seventh aspect for implementing any of the sixth aspect, the seventh aspect, and the sixth aspect Instructions in any of the possible designs.
  • a computer program product includes: computer program code that, when the computer program code runs on a computer, causes the computer to execute the foregoing first aspect, second aspect, and first A method in any one of the possible designs of the aspect or a possible design in any of the second aspects.
  • a computer program product includes: computer program code that, when the computer program code runs on a computer, causes the computer to execute the third aspect, the fourth aspect, and the fifth aspect. Aspect, any possible design in the third aspect, any possible design in the fourth aspect, or a method in any possible design in the fifth aspect.
  • a computer program product includes: computer program code that, when the computer program code runs on a computer, causes the computer to execute the sixth aspect, the seventh aspect, and the sixth aspect.
  • FIG. 1 is a schematic diagram of a communication system architecture in an embodiment of the present application
  • 2a is a schematic flowchart of one of early downlink data transmission methods according to an embodiment of the present application
  • 2b is a schematic flowchart of a second method for early transmission of downlink data according to an embodiment of the present application
  • 2c is a schematic flowchart of a third method for early transmission of downlink data according to an embodiment of the present application.
  • 3a is a schematic flowchart of a fourth method for early transmission of downlink data according to an embodiment of the present application.
  • 3b is a schematic flowchart of a fifth method for early transmission of downlink data according to an embodiment of the present application.
  • 3c is a schematic flowchart of a sixth method for early transmission of downlink data according to an embodiment of the present application.
  • 3d is a schematic flowchart of a seventh method for early transmission of downlink data according to an embodiment of the present application
  • 4a is a schematic flowchart of one of the implementation manners of the method for early transmission of downlink data according to an embodiment of the present application
  • 4b is a schematic flowchart of a second implementation manner of an early downlink data transmission method according to an embodiment of the present application.
  • 4c is a schematic flowchart of a third implementation manner of an early downlink data transmission method according to an embodiment of the present application.
  • 5a is a schematic flowchart of a fourth implementation manner of an early downlink data transmission method according to an embodiment of the present application.
  • 5b is a schematic flowchart of a fifth implementation manner of an early downlink data transmission method according to an embodiment of the present application.
  • 5c is a schematic flowchart of a sixth implementation manner of an early downlink data transmission method according to an embodiment of the present application.
  • 6a is a schematic flowchart of a seventh implementation manner of an early downlink data transmission method according to an embodiment of the present application.
  • 6b is a schematic flowchart of an eighth implementation manner of a method for early transmission of downlink data according to an embodiment of the present application.
  • 6c is a schematic flowchart of a method for implementing early transmission of downlink data according to an embodiment of the present application
  • FIG. 7a is a schematic flowchart of a tenth implementation manner of an early downlink data transmission method according to an embodiment of the present application.
  • 7b is a schematic flowchart of an eleventh implementation manner of an early downlink data transmission method according to an embodiment of the present application.
  • 7c is a schematic flowchart of a twelfth implementation manner of an early downlink data transmission method according to an embodiment of the present application.
  • 8a is a schematic flowchart of a thirteenth implementation manner of an early downlink data transmission method according to an embodiment of the present application
  • FIG. 8b is a schematic flowchart of a fourteenth implementation manner of an early downlink data transmission method according to an embodiment of the present application.
  • 8c is a schematic flowchart of a fifteenth implementation manner of an early downlink data transmission method according to an embodiment of the present application.
  • 9a is a schematic flowchart of a sixteenth implementation manner of an early downlink data transmission method according to an embodiment of the present application.
  • FIG. 9b is a schematic flowchart of a seventeenth implementation manner of an early downlink data transmission method according to an embodiment of the present application.
  • FIG. 9c is a schematic flowchart of an eighteenth implementation manner of an early downlink data transmission method according to an embodiment of the present application.
  • 10a is a schematic flowchart of a nineteenth implementation manner of an early downlink data transmission method according to an embodiment of the present application.
  • FIG. 10b is a schematic flowchart of Embodiment 20 of an implementation method of an early downlink data transmission method according to an embodiment of the present application.
  • FIG. 10c is a schematic flowchart of a twenty-first implementation manner of a method for early transmission of downlink data according to an embodiment of the present application.
  • FIG. 11 is a schematic diagram of a structure of an early data transmission device for downlink data according to an embodiment of the present application.
  • FIG. 12 is a second schematic structural diagram of a downlink data early transmission device according to an embodiment of the present application.
  • FIG. 13 is a third schematic structural diagram of an apparatus for early transmission of downlink data according to an embodiment of the present application.
  • the embodiments of the present application provide a method and a device for early transmission of downlink data, which implement early transmission of downlink data by using a simple connection establishment process, so as to improve resource utilization efficiency and reduce power consumption of a terminal.
  • the method and the device are based on the same inventive concept. Since the principle of the method and the device for solving the problem is similar, the implementation of the device and the method can be referred to each other, and duplicated details will not be repeated.
  • "and / or" describes the association relationship of the associated objects, and indicates that there can be three kinds of relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and There are three cases of B.
  • the communication method provided in the embodiment of the present application can be applied to a 4th generation (4G) communication system, a 5th generation (5G) communication system, or various future communication systems. Specifically, it can be applied to the communication scenario of MTC, the communication scenario of NB-IoT, and the transmission scenario of any downlink small data packet.
  • FIG. 1 shows an architecture of a possible communication system to which the method for early transmission of downlink data according to an embodiment of the present application is applicable.
  • the communication system 100 includes one or more access network devices, one or more Terminals and one or more core network devices. Each access network device can provide services to one or more terminals in the coverage area.
  • the access network devices are connected through an X2 interface for communication.
  • Core network devices are connected through the S1 interface.
  • the communication system 100 includes an access network device 101 and an access network device 101 ′, and terminals within the coverage of the access network device 101 are represented by a terminal 102, and the access network device 101 ′ The terminals within the coverage area are represented by the terminal 102 '.
  • the communication system 100 further includes a core network device 103 and a core network device 103 '.
  • the following describes the forms of access network equipment, terminals, and core network equipment included in the communication system by way of examples.
  • the access network device 101, the terminal 102, and the core network device 103 are used for description.
  • the access network device 101 is a node in a radio access network (RAN), and may also be referred to as a base station, and may also be referred to as a RAN node (or device).
  • access network equipment 101 are: gNB / NR-NB, transmission reception point (TRP), evolved node B (eNB), radio network controller (radio network controller), RNC), Node B (Node B, NB), base station controller (BSC), base transceiver station (BTS), home base station (e.g., home NodeB, or home NodeB, HNB) Baseband unit (BBU), or wireless fidelity (Wifi) access point (AP), or 5G communication system or network-side equipment in a possible future communication system.
  • TRP transmission reception point
  • eNB evolved node B
  • RNC radio network controller
  • Node B Node B
  • BSC base station controller
  • BTS base transceiver station
  • home base station e.g., home NodeB, or home NodeB
  • Terminal 102 also known as user equipment (UE), mobile station (MS), mobile terminal (MT), etc., is a device that provides voice or data connectivity to users. It can be an IoT device.
  • the terminal 102 includes a handheld device, a vehicle-mounted device, and the like having a wireless connection function.
  • the terminal 102 may be: a mobile phone, a tablet computer, a notebook computer, a handheld computer, a mobile Internet device (MID), a wearable device (such as a smart watch, a smart bracelet, a pedometer, etc.) , Vehicle equipment (for example, cars, bicycles, electric vehicles, airplanes, ships, trains, high-speed rail, etc.), virtual reality (VR) equipment, augmented reality (AR) equipment, industrial control (industrial control) Wireless terminals, smart home equipment (for example, refrigerators, televisions, air conditioners, electricity meters, etc.), smart robots, workshop equipment, wireless terminals in self driving, wireless terminals in remote medical surgery, Wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, or wireless terminals in smart homes, flight equipment (e.g., Smart robots, hot air balloons, drones, airplanes), etc.
  • Vehicle equipment for example, cars, bicycles, electric vehicles, airplanes, ships, trains, high-speed rail, etc.
  • VR virtual reality
  • the core network device 102 is used for communication between the network device 101 and an IP network.
  • the IP network may be the Internet, a private IP network, or other data networks.
  • the core network device 102 includes a mobile management entity (MME) / service-network gateway (S-GW).
  • MME mobile management entity
  • S-GW service-network gateway
  • the terminal involved in the embodiment of the present application may have a characteristic of a single service, for example, the downlink data of the terminal transmits only one downlink data packet at a time.
  • the embodiments of the present application may, but are not limited to, the following application scenarios:
  • Scenario 1 The amount of downlink data of the terminal is less than a set threshold
  • the core network device can send the downlink data of the terminal to the access network device through a network protocol IP packet;
  • the access network device can send the downlink data of the terminal to the terminal through a transmission block (TB);
  • the core network device sends the downlink data of the terminal to the access network device multiple times, but the access network device can send the downlink data received multiple times to the terminal through one TB.
  • both the core network device and the access network device may be referred to as network devices.
  • the embodiments of the present application may use words such as "first" and "second" to distinguish descriptions. It is understood that such words cannot be understood to indicate or imply relative importance. Nor can it be understood to indicate or imply a sequence.
  • the core idea of the embodiment of the present application is that the network device receives an indication and determines that the downlink data of the terminal has only one downlink data packet according to the instruction, and then sends the downlink data of the terminal to the terminal through a message, which can save signaling. Consume and avoid wasting resources.
  • Example 1 Indicate early transmission of downlink data
  • Example 2 Indicate that the downlink data of the terminal can be transmitted at one time, that is, the downlink data of the terminal can be transmitted in one message, for example, transmitted through message 4. Data and message 4 can be sent in one TB;
  • message 4 is the fourth message that is exchanged between the terminal and the network device during the random access process.
  • Example 3 Instruct the terminal not to send an uplink response message or uplink data after receiving downlink data
  • Example 4 Instruct the terminal to release the connection after receiving the downlink data.
  • Example 5 Indicate a single downlink data packet, that is, indicate that the core network device can send the downlink data of the terminal through an IP packet, which is represented as a single downlink data packet (single single packet) or a single downlink data (single downlink data)
  • Example 6 Indicate a single downlink data packet, that is, indicate that the access network device can send the downlink data of the terminal through a TB, which is expressed as a single downlink data packet (single single packet) or a single downlink data (single DL data).
  • Example 7 Instructing the transmission of a small packet can be understood as that the amount of downlink data of the terminal is less than a threshold.
  • an interactive device may be represented by a terminal, a first network device, a second network device, and a third network device.
  • the first network device is an access network device.
  • the access network device may be an eNB.
  • the second network device and the third network device are core network devices.
  • the second network device is recorded as the first core network device
  • the third network device is recorded as the second core network device
  • the second network device may be the MME
  • the third The network device may be an S-GW.
  • the terminal sends a message 1 (Msg1) to the first network device.
  • the first network device receives a message 1 (Msg1) from the terminal, where the message 1 is a random access preamble.
  • the first network device broadcasts several random access preambles through a broadcast message.
  • the terminal needs to initiate a random access process, it randomly selects one of the received random access preambles, and selects the selected random access preamble.
  • the random access preamble is sent to the first network device.
  • the terminal Before S201a, the terminal receives a paging message sent by the first network device.
  • S202a The first network device sends a message 2 (Msg2) to the terminal, and the terminal receives the message 2 from the first network device.
  • Msg2 message 2
  • the message 2 is a random access response (random access response).
  • S203a The terminal sends message 3 (Msg3) to the first network device, and the first network device receives message 3 (Msg3) from the terminal.
  • the message 3 carries an indication, and the meaning of the indication can refer to the description above.
  • the message 3 may be an RRC message, which is recorded here as a first RRC message.
  • the first RRC message is an RRC connection resume request (RRC connection request) message, which is used to request the restoration of an RRC connection.
  • the first RRC message may also carry a resume ID, a resume cause, and a truncated resume MAC-I.
  • the MAC-I is used for integrity protection.
  • Message authentication code (message authentication code for integration).
  • the resume ID is used to identify the suspended terminal;
  • the resumecause is used to indicate the reason for the terminal to resume the connection, for example, the value of the resumecause is called mobile accessing-access (mt-Access), or resume
  • the cause value is a newly added value, and the newly added value is used to indicate that the reason for the connection restoration is to transmit a single downlink data; short-resume MAC-I is used to protect the integrity of Msg3 to prevent Msg3 from being tampered with.
  • message A carrying B there can be multiple methods for message A carrying B.
  • the cell or domain included in message A can be used to carry B, that is, it can be understood that message A includes B.
  • B and message A can be encapsulated together to realize that message A carries B, such as encapsulating B and message A in a MAC PDU, and encapsulating B and message A in a transport block, for example. medium.
  • the message A carrying B may be a message 3 carrying instruction (ie, the first instruction in the text), or a message 4 carrying downlink data.
  • the third network sends downlink data to the terminal, and the terminal receives downlink data from the third network device.
  • Instructions are carried in the downlink data, and the meaning of the instructions is as described above.
  • the header of a GPRS tunneling protocol (GTP-U) packet of a user plane of a downlink data packet (GTP-U) may carry the indication, where GPRS is a general packet radio service.
  • S204a The first network device sends a message 4 (Msg4) to the terminal, and the terminal receives the message 4 from the first network device.
  • Msg4 message 4
  • the message 4 carries downlink data, and the downlink data is downlink data delivered by the third network device to the first network device.
  • the first network device may send downlink data to the terminal by using message 4 according to the instruction.
  • Message 4 may be an RRC message, which is recorded as a second RRC message.
  • the second RRC message is an RRC connection release message.
  • message 4 carries downlink data, it can be understood that message 4 and downlink data are encapsulated in one message.
  • message 4 includes a second RRC message and downlink data.
  • Msg4 is carried on the logical channel of the common control channel (CCCH) (that is, carried on SRB0), and the downlink data is carried on the dedicated service channel (DTCH) channel (that is, carried on the DRB)
  • CCCH common control channel
  • DTCH dedicated service channel
  • the data on these two channels namely the MAC service data control unit (service data unit, MAC SDU), is multiplexed at the medium access control (MAC) layer to form a media access control protocol data unit ( medium access control packet data unit (MAC PDU), the first network device sends a MAC PDU to the terminal, and the terminal receives the MAC PDU sent by the first network device.
  • MAC medium access control
  • the message 4 may carry a resume ID, a release cause, and a next hop chaining count (NCC).
  • NCC next hop chaining count
  • resume ID is used to identify the suspended terminal
  • releasecause is used to indicate the reason for releasing the terminal context.
  • the value of releasecause may be RRC suspension (ie rrc-suspend).
  • the first network device can send a single downlink data to the terminal in a random access process according to an instruction sent by the terminal, without establishing an RRC connection of the terminal, so that the terminal is idle in the idle state.
  • the downlink data can be received, which helps reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • an instruction may also be sent to the access network device through the core network device.
  • the specific process of the second method for early transmission of downlink data provided in the embodiment of the present application is as follows.
  • the third network device sends a downlink data notification message to the second network device, and the second network device receives the downlink data notification message from the third network device.
  • the downlink data notification message carries an indication.
  • the indication refer to the description above.
  • the downlink data notification message may also carry an identifier of the terminal, for example, S-TMSI and / or Resume ID.
  • the second network device sends a paging message to the first network device, and the first network device receives the paging message from the second network device.
  • the paging message carries an instruction. Similarly, the meaning of the instruction can refer to the description above.
  • the paging message may also carry the identity of the terminal, for example, S-TMSI and / or Resume ID.
  • the first network device sends the Resume ID of the terminal to the second network device.
  • the first network device sends a paging message to the terminal, and the terminal receives the paging message sent by the first network device.
  • an indication may also be carried in the paging message sent in this step, and the meaning of the indication may refer to the description above.
  • S206b The terminal sends message 3 (Msg3) to the first network device, and the first network device receives message 3 (Msg3) from the terminal.
  • the message 3 is a first RRC message, and the first RRC message may be used to request restoration of an RRC connection.
  • the first RRC message is an RRC connection restoration request (RRC connection request) message.
  • the first RRC message may also carry a resume ID (resume ID), a resume cause (resume cause), and a short resume MAC-I.
  • resume ID resume ID
  • resume cause resume cause
  • short resume MAC-I short resume MAC-I
  • the first network device After receiving the first RRC message, the first network device determines that the suspended terminal is the terminal indicated by the instruction sent by the core network according to the resume ID or the mapping relationship between the resume ID and the S-TMSI, and further determines the terminal.
  • the downlink data of the terminal can be transmitted at one time, so the downlink data of the terminal is carried in message 4 in subsequent S207b.
  • the third network device sends downlink data to the first network device, and the first network device receives the downlink data from the third network device.
  • Instructions are carried in the downlink data, and the meaning of the instructions is as described above.
  • the indication may be carried in the header of the GTP-U protocol packet of the downlink data packet.
  • the first network device can send a single downlink data to the terminal in the random access process according to an instruction sent by the core network device without establishing an RRC connection of the terminal, so that the terminal is idle.
  • the state can finish receiving the downlink data, which helps to reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • an instruction may be sent to the access network device through both the core network device and the terminal.
  • the specific process of the third method for early transmission of downlink data provided in the embodiment of the present application is as follows.
  • the third network device sends a downlink data notification message to the second network device, and the second network device receives the downlink data notification message from the third network device.
  • the downlink data notification message carries an indication.
  • the downlink data notification message may also carry the identity of the terminal, for example, S-TMSI.
  • the second network device sends a paging message to the first network device, and the first network device receives the paging message from the second network device.
  • the paging message carries an instruction. Similarly, the meaning of the instruction can refer to the description above.
  • the paging message may also carry the identity of the terminal, for example, S-TMSI.
  • the first network device sends a paging message to the terminal, and the terminal receives the paging message sent by the first network device.
  • an indication may also be carried in the paging message sent in this step, and the meaning of the indication may refer to the description above.
  • S204c The terminal sends a message 1 (Msg1) to the first network device, and the first network device receives a message 1 (Msg1) from the terminal, where the message 1 is a random access preamble.
  • S205c The first network device sends a message 2 (Msg2) to the terminal, and the terminal receives the message 2 from the first network device.
  • Msg2 message 2
  • the message 2 is a random access response (random access response).
  • the terminal sends message 3 (Msg3) to the first network device, and the first network device receives message 3 (Msg3) from the terminal.
  • the message 3 carries an indication, and the meaning of the indication can refer to the description above.
  • the message 3 may be an RRC connection restoration request (RRC connection request) message, which is used to request the restoration of an RRC connection.
  • RRC connection request RRC connection request
  • the first RRC message may also carry a resume ID (resume ID), a resume cause (resume cause), and a short resume MAC-I.
  • resume ID resume ID
  • resume cause resume cause
  • short resume MAC-I short resume MAC-I
  • the first network device receives the first RRC message, and according to the instruction, determines that the downlink data of the terminal can be completed in one transmission. Therefore, in the subsequent S207c, the downlink data of the terminal is carried in the message 4.
  • the third network sends downlink data to the terminal, and the terminal receives downlink data from the third network device.
  • Instructions are carried in the downlink data, and the meaning of the instructions is as described above.
  • the indication may be carried in the header of the GTP-U protocol packet of the downlink data packet.
  • S207c The first network device sends a message 4 (Msg4) to the terminal, and the terminal receives the message 4 from the first network device.
  • the message 4 carries downlink data, and the downlink data is downlink data delivered by the third network device to the first network device.
  • the message 4 may be an RRC message, for example, an RRC connection release message.
  • the first network device can send a single downlink data to the terminal in the random access process according to the instructions sent by the terminal and the core network device without establishing an RRC connection of the terminal, so that the terminal In the idle state, the downlink data can be completely received, which helps reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • Method 1 Before the first network device sends a message 4 (Msg4) to the terminal, the context information of the terminal is restored.
  • the context information of the terminal includes the NCC, which is recorded here as the first NCC.
  • the first network device uses the first NCC to derive
  • the new key, recorded as the first key, is represented by K 1 RRCenc .
  • the terminal's context information also contains the old key, which is recorded as the third key and is represented by K 3 RRCint .
  • the first network device uses a third key to perform integrity protection on the second RRC message, and uses the first key to encrypt downlink data.
  • the second RRC message and the encrypted downlink data for performing integrity protection are carried in message 4 and sent to the terminal.
  • the terminal After receiving the message 4 (Msg4) sent by the first network device, the terminal recovers the context information of the terminal.
  • the context information of the terminal includes the first NCC and the third key.
  • the terminal uses the first NCC to derive the first key, uses the third key to perform integrity protection check on the received second RRC message, and uses the first key to decrypt the received downlink data.
  • Method 2 Before the first network device sends a message 4 (Msg4) to the terminal, the context information of the terminal is restored.
  • the context information of the terminal includes the first NCC, and the first network device uses the first NCC to derive the first key and The second key, the first key is represented by K 1 RRCenc , and the second key is represented by K 2 RRCint .
  • the first network device uses the second key to perform integrity protection on the second RRC message, and uses the first key to encrypt downlink data.
  • the second RRC message and the encrypted downlink data for performing integrity protection are carried in message 4 and sent to the terminal.
  • the terminal After receiving the message 4 (Msg4) sent by the first network device, the terminal recovers the context information of the terminal.
  • the context information of the terminal includes the first NCC.
  • the terminal uses the first NCC to derive the first key and the second key, uses the second key to perform integrity protection check on the received second RRC message, and uses the first key to decrypt the received downlink data.
  • Method 3 Before the first network device sends a message 4 (Msg4) to the terminal, the context information of the terminal is restored.
  • the context information of the terminal includes the first NCC, and the first network device uses the first NCC to derive the first key, Second and fourth keys.
  • the second key is represented by K 2 RRCint
  • the fourth key is represented by K 4 RRCenc .
  • the first network device uses a second key to perform integrity protection on the second RRC message, uses a fourth key to encrypt the second RRC message, and uses the first key to encrypt downlink data.
  • the second RRC message and the encrypted downlink data that perform integrity protection and encryption are carried in message 4 and sent to the terminal.
  • the terminal recovers the context information of the terminal before sending the message 3 (Msg3) to the first network device.
  • the context information of the terminal includes the first NCC, and the terminal uses the first NCC to derive the first key and the second Key and fourth key.
  • the terminal uses the second key and the fourth key to perform integrity protection checksum decryption on the second RRC message, and uses the first key to decrypt the received downlink data.
  • Method 4 Before the first network device sends a message 4 (Msg4) to the terminal, the context information of the terminal is restored.
  • the context information of the terminal includes the old key and is recorded as the third key.
  • the first network device carries a second NCC in a message 4 (Msg4) sent to the terminal, and uses a fifth key derived by the second NCC, and the fifth key is represented by K 5 RRCenc .
  • the first network device uses the third key to perform integrity protection on the second RRC message, and uses the derived fifth key to encrypt the downlink data.
  • the second RRC message and the encrypted downlink data for performing integrity protection are carried in message 4 and sent to the terminal.
  • the terminal restores the context information of the terminal before sending the message 3 (Msg3) to the first network device.
  • the context information of the terminal contains the old key and is recorded as the third key.
  • the terminal receives message 4 and uses the third key to perform integrity protection check on the second RRC message.
  • the message 4 carries a second NCC, and the terminal uses the second NCC to derive a fifth key, and uses the fifth key to decrypt the downlink data.
  • Method 5 Before the first network device sends a message 4 (Msg4) to the terminal, the context information of the terminal is restored.
  • the first network device carries a second NCC in the message 4 (Msg4) sent to the terminal, and the first network device uses The second NCC derives a fifth key and a sixth key, and the sixth key is represented by K 6 RRCint .
  • the first network device uses the derived sixth key to perform integrity protection on the second RRC message, and uses the derived fifth key to encrypt downlink data.
  • the second RRC message and the encrypted downlink data for performing integrity protection are carried in message 4 and sent to the terminal.
  • the terminal restores the context information of the terminal before sending the message 3 (Msg3) to the first network device.
  • the terminal receives message 4, which carries the second NCC.
  • the terminal uses the second NCC to derive the fifth key and the sixth key, uses the sixth key to perform integrity protection check on the second RRC message, and uses the fifth The key decrypts the downstream data.
  • the specific process of the fourth method for early transmission of downlink data according to the embodiment of the present application is as follows.
  • S301a The terminal sends a message 1 (Msg1) to the first network device, and the first network device receives a message 1 (Msg1) from the terminal, where the message 1 is a random access preamble.
  • the terminal Before S301a, the terminal receives a paging message (Paging) sent by the first network device.
  • Paging paging message
  • S302a The first network device sends a message 2 (Msg2) to the terminal, and the terminal receives the message 2 from the first network device.
  • Msg2 message 2
  • the message 2 is a random access response (random access response).
  • the terminal sends a first RRC message to the first network device, and the first network device receives the first RRC message from the terminal.
  • the first RRC message carries an instruction, which is recorded as the first instruction.
  • the meaning of the first instruction refer to the description above.
  • the first network device sends a second instruction to the second network device, and the second network device receives the second instruction from the first network device.
  • the second indication may be carried in a terminal initialization message (Initial UE Message).
  • the first network device sends a terminal initialization message to the second network device.
  • the second network device receives the terminal initialization message from the first network device, and the terminal initialization message carries a second instruction.
  • the third network device sends downlink data to the second network device, and the second network device receives the downlink data sent by the third network device.
  • the second network device encapsulates the downlink data in the NAS message.
  • the second network device sends the downlink data to the first network device through a downlink NAS transmission.
  • the first network device receives the downlink data sent by the second network device. NAS message.
  • the first network device sends a second RRC message to the terminal, and the terminal receives the second RRC message from the first network device.
  • the second RRC message carries downlink data.
  • the first network device determines that the downlink data of the terminal can be transmitted in one time according to the instruction in S303a. Then, the first network device encapsulates the received downlink NAS message containing the downlink data of the terminal in a second RRC message, and encapsulates the second RRC message. The RRC message is sent to the terminal.
  • the first RRC message is an RRC data early request (RRC data early request) message, which is used to request an early transmission of uplink data.
  • the RRC data early transmission request message carries a first indication, and the meaning of the first indication may be single packet Or single DL data can also be indicated by dedicated Info NAS.
  • the original function of dedicated Info NAS is to carry the uplink data of early transmission. In the scenario of early transmission of downlink data, it is assumed that the terminal does not have uplink data, and the RRC data
  • the early transmission request message is used to notify the early transmission of downlink data, so the dedicated InfoInfo NAS can be set to empty NULL, which is used to indicate that no uplink data is carried, and further indicates that the downlink data is transmitted early.
  • the second RRC message is an RRC data early complete (RRC data early completion) message, which is used to carry the downlink data of the early transmission.
  • the first RRC message is an RRC Connection Request (RRC Connection Request) message. Used to request the establishment of an RRC connection.
  • the RRC connection request message carries a first indication.
  • the second RRC message is an RRC data early transmission completion message, which is used to carry the downlink data of the early transmission.
  • the first RRC message is an RRC connection request message, which is used to request establishment of an RRC connection.
  • the RRC connection request message carries a first indication.
  • the second RRC message is an RRC connection release message, which is used to notify the release of the RRC connection and to carry the downlink data of the early transmission.
  • the second network device can encapsulate the downlink data of the terminal in a NAS message and send it to the terminal via the first network device according to the instruction sent by the terminal.
  • the RRC connection of the terminal does not need to be established, so that the terminal In the idle state, the downlink data can be completely received, which helps reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • an instruction may also be sent to the second network device through the third network device.
  • the specific process of the fifth method for early transmission of downlink data provided in the embodiment of the present application is as follows.
  • the third network device sends a downlink data notification message to the second network device, and the second network device receives the downlink data notification message from the third network device.
  • the downlink data notification message carries an indication.
  • the downlink data notification message may also carry the identity of the terminal, for example, S-TMSI.
  • the second network device sends a paging message to the first network device, and the first network device receives the paging message from the second network device.
  • the paging message carries an instruction. Similarly, the meaning of the instruction can refer to the description above.
  • the paging message may also carry the identity of the terminal, for example, S-TMSI.
  • S303b The first network device sends a paging message to the terminal, and the terminal receives the paging message sent by the first network device.
  • an indication may also be carried in the paging message sent in this step, and the meaning of the indication may refer to the description above.
  • S304b The terminal sends a message 1 (Msg1) to the first network device, and the first network device receives a message 1 (Msg1) from the terminal, where the message 1 is a random access preamble.
  • S305b The first network device sends a message 2 (Msg2) to the terminal, and the terminal receives the message 2 from the first network device.
  • Msg2 message 2
  • the message 2 is a random access response (random access response).
  • S306b The terminal sends a first RRC message to the first network device, and the first network device receives the first RRC message from the terminal.
  • the third network device sends downlink data to the second network device, and the second network device receives the downlink data sent by the third network device.
  • the second network device encapsulates the downlink data in a NAS message, the second network device sends the downlink data to the first network device through downlink NAS transmission, and the first network device receives the downlink NAS message sent by the second network device.
  • the second network device determines that the downlink data of the terminal can be transmitted at one time according to the instruction, and then the second network device encapsulates the downlink data in a NAS message and sends it to the first network device.
  • the first network device sends a second RRC message to the terminal, and the terminal receives the second RRC message from the first network device.
  • the second RRC message carries downlink data.
  • the first network device determines that the downlink data of the terminal can be transmitted in one time according to the instructions in S302b or S306b, and then the first network device encapsulates the received NAS message containing the downlink data of the terminal in a second RRC message, and The second RRC message is sent to the terminal.
  • the second network device can encapsulate the downlink data of the terminal in a NAS message and send it to the terminal via the first network device according to the instruction sent by the third network device. There is no need to establish the RRC connection of the terminal. , So that the terminal can receive downlink data in the idle state, which helps reduce resource consumption, reduce signaling overhead, and reduce power consumption of the terminal.
  • sending the instruction to the second network device through the third network device may also be implemented in the following manner.
  • the specific process of the sixth method for early transmission of downlink data provided in the embodiment of the present application is as follows.
  • the third network device sends a downlink data notification message to the second network device, and the second network device receives the downlink data notification message from the third network device.
  • the downlink data notification message carries an indication.
  • the downlink data notification message may also carry the identity of the terminal, for example, S-TMSI.
  • the second network device sends a paging message to the first network device, and the first network device receives the paging message from the second network device.
  • the paging message may also carry the identity of the terminal, for example, S-TMSI.
  • the first network device sends a paging message to the terminal, and the terminal receives the paging message sent by the first network device.
  • the terminal sends a message 1 (Msg1) to the first network device.
  • the first network device receives a message 1 (Msg1) from the terminal, where the message 1 is a random access preamble.
  • the first network device sends message 2 (Msg2) to the terminal, and the terminal receives message 2 from the first network device.
  • the message 2 is a random access response (random access response).
  • the terminal sends a first RRC message to the first network device, and the first network device receives the first RRC message from the terminal.
  • the third network device sends downlink data to the second network device, and the second network device receives the downlink data sent by the third network device.
  • the second network device encapsulates the downlink data in a NAS message, the second network device sends the downlink data to the first network device through downlink NAS transmission, and the first network device receives the downlink NAS message sent by the second network device.
  • the NAS message also carries an indication. For the meaning of the indication, refer to the description above.
  • the first network device sends a second RRC message to the terminal, and the terminal receives the second RRC message from the first network device.
  • the second RRC message carries downlink data.
  • the first network device encapsulates the received NAS message in a second RRC message, and sends the second RRC message to the terminal.
  • the second network device can encapsulate the downlink data of the terminal in a NAS message and send it to the terminal via the first network device according to the instruction sent by the third network device. There is no need to establish the RRC connection of the terminal , So that the terminal can receive downlink data in the idle state, which helps reduce resource consumption, reduce signaling overhead, and reduce power consumption of the terminal.
  • sending the instruction to the second network device through the third network device may also be implemented in the following manner.
  • the specific process of the seventh method for early transmission of downlink data provided in the embodiment of the present application is as follows.
  • the third network device sends a downlink data notification message to the second network device, and the second network device receives the downlink data notification message from the third network device.
  • the downlink data notification message may also carry the identity of the terminal, for example, S-TMSI.
  • the second network device sends a paging message to the first network device, and the first network device receives the paging message from the second network device.
  • the paging message may also carry the identity of the terminal, for example, S-TMSI.
  • the first network device sends a paging message to the terminal, and the terminal receives the paging message sent by the first network device.
  • the terminal sends a message 1 (Msg1) to the first network device, and the first network device receives message 1 (Msg1) from the terminal, where the message 1 is a random access preamble.
  • S305d The first network device sends a message 2 (Msg2) to the terminal, and the terminal receives the message 2 from the first network device.
  • Msg2 message 2
  • the message 2 is a random access response (random access response).
  • S306d The terminal sends a first RRC message to the first network device, and the first network device receives the first RRC message from the terminal.
  • the third network device sends downlink data to the second network device, and the second network device receives the downlink data sent by the third network device.
  • the downlink data carries an instruction, and the meaning of the instruction may refer to the description above.
  • the second network device encapsulates the downlink data in the NAS message.
  • the second network device sends the downlink data to the first network device through downlink NAS transmission, and the first network device receives the downlink NAS message sent by the second network device.
  • the NAS message also carries an indication. For the meaning of the indication, refer to the description above.
  • the first network device sends a second RRC message to the terminal, and the terminal receives the second RRC message from the first network device.
  • the second RRC message carries downlink data.
  • the first network device encapsulates the received NAS message in a second RRC message, and sends the second RRC message to the terminal.
  • the second network device can encapsulate the downlink data of the terminal in a NAS message and send it to the terminal via the first network device according to the instruction sent by the third network device. There is no need to establish the RRC connection of the terminal. , So that the terminal can receive downlink data in the idle state, which helps reduce resource consumption, reduce signaling overhead, and reduce power consumption of the terminal.
  • the following describes the possible functions or meanings of the first RRC message and the second RRC message by way of example with reference to the fifth method of early transmission of downlink data, the sixth method of early transmission of downlink data, and the seventh method of early transmission of downlink data. It is applicable to these three methods of early transmission of downlink data.
  • the first RRC message is an RRC data early request (RRC data early request) message, which is used to request an early transmission of uplink data.
  • the RRC data early request message may carry dedicated Info NAS.
  • the original function of NAS is dedicated to bearer.
  • Early transmission of uplink data In the scenario of early transmission of downlink data, assuming that the terminal does not have uplink data, the dedicated InfoNAS can be set to null and used to indicate that no uplink data is carried.
  • the second RRC message is an RRC data early complete (RRC data early completion) message, which is used to carry the downlink data of the early transmission.
  • the first RRC message is an RRC connection request message. Used to request the establishment of an RRC connection.
  • the second RRC message is an RRC data early transmission completion message, which is used to carry the downlink data of the early transmission.
  • the first RRC message is an RRC connection request message, which is used to request establishment of an RRC connection.
  • the second RRC message is an RRC connection release message, which is used to notify the release of the RRC connection and to carry the downlink data of the early transmission.
  • the first network device (that is, the access network device) is the base station
  • the second network device (that is, the first core network device) is the MME
  • the third core network device (that is, the second core network device) is S- GW is introduced as an example.
  • the terminal is in a suspended state before starting the steps described below.
  • the base station determines that the terminal has no uplink and downlink data
  • the base station requests the MME to suspend (ie, suspend) the terminal.
  • the suspension means that the base station releases the RRC connection with the terminal, but the base station does not release the context information of the terminal.
  • the terminal receives a positive response from the MME
  • the terminal is allowed to suspend, and the base station sends an RRC connection release message to the terminal, and instructs the terminal to suspend in the RRC connection release message.
  • the terminal saves the configuration information of the base station for the terminal.
  • the terminal is in an idle state (that is, an idle state).
  • early transmission of downlink data is performed through the following procedure.
  • FIG. 4a shows one of the implementation manners of the early downlink data transmission method provided by the embodiment of the present application.
  • One of the implementation manners is based on the description of one of the early downlink data transmission methods shown in FIG. 2a. The implementation is described in detail below. One way.
  • the S-GW sends a downlink data notification message (downlink data notification) to the MME, and the MME receives the downlink data notification message sent by the S-GW.
  • a downlink data notification message downlink data notification
  • the downlink data notification message carries an identifier of the terminal, for example, the identifier is an EPS system temporary mobile subscriber identity (EPS-TMSI, S-TMSI), where the EPS is an evolved packet system.
  • EPS-TMSI EPS system temporary mobile subscriber identity
  • S-TMSI EPS system temporary mobile subscriber identity
  • the MME After receiving the downlink data notification message sent by the S-GW, the MME sends a paging message to the base station.
  • the base station receives a paging message (that is, a paging message) sent by the MME.
  • the paging message is used to instruct the base station to page the terminal.
  • the base station After receiving the paging message sent by the MME, the base station sends the paging message in a broadcast form.
  • the terminal in the idle state periodically monitors the paging message.
  • the terminal monitors the paging message sent by the base station and confirms that the paging message carries its own identity, the terminal triggers the following steps.
  • S404a The terminal sends a random access preamble to the base station, and the base station receives the random access preamble sent by the terminal.
  • the base station broadcasts several random access preambles to all terminals through a broadcast message.
  • the terminal randomly selects one of the random access preambles broadcasted by the base station, and broadcasts the random access preambles broadcasted by the base station.
  • a resource is randomly selected from the resources, and the selected random access preamble is sent on the selected resource.
  • S405a The base station sends a random access response (RAR) to the terminal, and the terminal receives the random access response sent by the base station.
  • RAR random access response
  • the base station monitors the random access preamble sent by the terminal on the resources of the random access preamble, and sends a RAR to the terminal when a random access preamble is detected.
  • the RAR includes: a timing (advanced, TA) for the terminal to send Msg3, and an uplink resource (UL grant) for the terminal to send Msg3.
  • S406a The terminal recovers a signaling radio bearer (Signaling, Radio, Bearer, SRB).
  • the terminal recovers SRB1, where SRB1 is used to send and receive RRC messages and to receive NAS messages before SRB2 is established.
  • S407a The terminal sends a message 3 (that is, Msg3) to the base station, and the base station receives the Msg3 sent by the terminal.
  • a message 3 that is, Msg3
  • Msg3 may be an RRC connection resume request (RRC connection request) message.
  • RRC connection request RRC connection request
  • Msg3 also includes an indication, and the meaning of the indication may refer to the description of Examples 1 to 7 above. .
  • the RRC connection restoration request message also carries the following information: a resume identifier (resume ID), a resume cause (resume cause), and a short resume MAC-I.
  • resume ID is used to identify the suspended terminal, that is, to identify the terminal that sent the RRC connection resume request message
  • resumecause is used to indicate the reason for the terminal to resume the connection, for example, the value of resumecause is the called connection (Mobile-terminating-Access, mt-Access), or the value of resume is a newly added value, which is used to indicate that the reason for resuming the connection is to transmit a single downlink data
  • short MAC-I is used to Msg3 Integrity protection to prevent Msg3 from being tampered with.
  • S408a The base station sends a terminal context recovery request (UE context request) message to the MME according to the instruction received in S407, and the MME receives the terminal context recovery request message sent by the base station.
  • UE context request terminal context recovery request
  • the terminal context recovery request message is used to request to recover the context information of the terminal.
  • the MME sends a context recovery response message (UE context response) to the base station, and the base station receives the context recovery response message sent by the MME.
  • UE context response UE context response
  • the base station After receiving the context recovery response message sent by the MME, the base station recovers the context information of the terminal.
  • the context information of the terminal includes the NCC, which is recorded here as the first NCC.
  • the first NCC may be received from the terminal last time. Msg4.
  • the base station uses the first NCC to derive a new key, records it as the first key, and uses K 1 RRCenc to indicate that the first key is used to encrypt downlink data.
  • the context information of the terminal also contains the old key, which is recorded as the third key, which is represented by K 3 RRCint .
  • the third key is used to protect the integrity of the RRC connection release message.
  • the base station may also use the first NCC to derive the second key and the fourth key.
  • the second key is represented by K 2 RRCint and the fourth key is represented by K 4 RRCenc .
  • the second key is used to protect the integrity of the RRC connection release message, and the fourth key is used to encrypt the RRC connection release message.
  • the S-GW sends downlink data to the base station, and the base station receives downlink data sent by the S-GW.
  • the S-GW sends the downlink data to the base station an indication, and the meaning of the indication may refer to the description above.
  • the header of the GTP-U protocol packet of the downlink data packet carries the indication.
  • S410a and S412a have no strict execution order.
  • the S-GW can perform this step after executing S409a.
  • S413a A process in which the base station and the MME interact to suspend the context of the terminal, and a process in which the MME and the S-GW exchange bearer modify (bearer) messages.
  • the base station initiates the process of suspending the context of the terminal and the process of interacting with the bearer modification message according to the instruction received in S407a or S412a.
  • S414a The base station sends a message 4 (Msg4) to the terminal, and the terminal receives Msg4 sent by the base station.
  • Msg4 message 4
  • Msg4 includes downlink data of the terminal, and Msg4 also includes an RRC connection release message.
  • the base station encapsulates the RRC connection release message and the downlink data in a message (ie, Msg4) and sends it to the terminal.
  • the terminal receives the message sent by the base station, and the terminal obtains the RRC connection release message and the downlink data.
  • the base station may use method 1 for integrity protection and encryption. Specifically, the base station uses the third key to perform integrity protection on the RRC connection release message, and uses the first key to encrypt the downlink data.
  • the RRC connection release message and the encrypted downlink data that perform integrity protection are carried in message 4 and sent to the terminal.
  • the base station may also use method 2 for integrity protection and encryption. Specifically, the base station uses the second key to perform integrity protection on the RRC connection release message, and uses the first key to encrypt the downlink data.
  • the RRC connection release message and the encrypted downlink data that perform integrity protection and encryption are carried in message 4 and sent to the terminal.
  • the base station determines the early transmission of downlink data according to the received instructions, or determines that the downlink data sent by the terminal can be transmitted to the terminal in a TB, so the terminal does not need to enter the RRC connection state.
  • the base station carries the RRC connection release message to the terminal to carry the Downstream data.
  • the base station may, but is not limited to, determine that the downlink data sent to the terminal can be sent to the terminal at one time (that is, it can be carried in a TB and sent to the terminal). It should be noted that this part of the description can be applied to the early downlink data transmission methods described above.
  • the base station is the first network device in the foregoing embodiments.
  • the first network device can also determine the downlink data sent to the terminal by this method. It can be sent to the terminal at one time, so as to send downlink data to the terminal through a message.
  • the base station may determine that the downlink data can be sent to the terminal at one time according to the instruction sent by the S-GW received in S411 or according to the instruction sent by the terminal received in S407, thereby sending an RRC connection release message to the terminal.
  • the second method the base station starts a timer when S412a receives the downlink data sent by the S-GW, and when the timer expires, the base station has not received the downlink data again, the base station determines that the S-GW sends the data to the terminal.
  • the downlink data has only one downlink data packet, and it is determined that the downlink data can be sent to the terminal at one time; or, when the timer expires, the base station receives multiple downlink data packets, but the base station determines that the multiple downlink data packets can be sent to the terminal through one TB. .
  • the downlink data received by the base station carries an indication, which is used to indicate that the terminal will not have an uplink response message or uplink data after receiving the downlink data. In these cases, the terminal is not required to enter the connected state, so the base station sends an RRC connection release message to the terminal.
  • the RRC connection release message carries a resume ID (resume ID) and a release cause (release cause).
  • the NCC can also be carried in the RRC connection release message.
  • the terminal receives the RRC connection release message through SRB1 recovered in S406a.
  • the resume ID is used to identify the suspended terminal, that is, the terminal that sent the RRC connection resume request message in S407, and the resume ID is the same as the resume ID in the RRC connection resume request message in S407a.
  • Releasecause is used to indicate the reason for releasing the terminal context.
  • the value of releasecause can be RRC suspend (ie rrc-suspend).
  • the terminal saves the NCC carried in the RRC connection release message, and the NCC can be used for the next uplink data early transmission and / or the downlink data early transmission.
  • the terminal restores the context information.
  • the context information restored by the terminal includes the old key and the first NCC.
  • the old key may be recorded as the third key.
  • the third key may be used to perform integrity protection check on the RRC connection release message
  • the first NCC may be used to derive the first key
  • the first key may be used to decrypt downlink data.
  • the context information restored by the terminal may further include SRB2, data radio bearer (DRB).
  • the first NCC may be from the Msg4 received by the terminal last time.
  • the first NCC may be used to derive a first key
  • the first key may be used to decrypt downlink data
  • the first NCC may also be used to derive a second key.
  • the second key is used to perform integrity protection check on the RRC connection release message.
  • the terminal sends an RRC connection restoration request message to the base station, and receives the RRC connection release message and downlink data returned by the base station, then the terminal determines that there is only one downlink data packet and recovers the context information.
  • SRB2 is used to carry RRC messages and NAS messages.
  • S416a The terminal performs integrity protection check on the RRC connection release message, and decrypts downlink data.
  • the terminal uses the third key recovered in S414 to perform integrity protection check on the RRC connection release message, and uses the first key to decrypt the downlink data;
  • the terminal performs integrity protection check on the RRC connection release message using the second key deduced in S414, and uses the first key to decrypt the downlink data.
  • the terminal suspends the context information and enters an idle state (idle state).
  • the terminal suspends the bearer configuration and the security configuration, for example, the terminal suspends the SRB, DRB, and security context.
  • the terminal sends an instruction for early transmission of downlink data to the access network device (that is, the base station), and the base station can send the downlink data to the terminal together with the RRC message, for example, the RRC message It can be an RRC connection release message.
  • the terminal can receive downlink data without entering the connected state, which can help reduce resource consumption, signaling overhead, and terminal. Power consumption.
  • FIG. 4b shows the second implementation manner of the early downlink data transmission method provided by the embodiment of the present application.
  • the second implementation manner is based on the description of one of the early downlink data transmission methods shown in FIG. 2a. The implementation is described in detail below. Way two.
  • S406b The terminal restores the context information.
  • the context information restored by the terminal includes at least a first NCC, and the first NCC is used to derive a first key, a second key, and a fourth key.
  • the first key is used to decrypt the downlink data
  • the second key is used to perform the integrity protection check on the RRC connection release message
  • the fourth key is used to decrypt the RRC connection release message.
  • the context information recovered by the terminal may further include SRB1, SRB2, and DRB, where SRB1 is used to send and receive RRC messages and to receive NAS messages before SRB2 is established.
  • the context information of the terminal recovered by the base station includes the first NCC, and the base station uses the first NCC to derive a new first key, a second key, and a fourth key.
  • the second key is used to release the RRC connection message.
  • the fourth key is used to encrypt the RRC connection release message.
  • S414b The base station sends a message 4 (Msg4) to the terminal, and the terminal receives Msg4 sent by the base station.
  • Msg4 message 4
  • Msg4 includes downlink data of the terminal, and Msg4 also includes an RRC connection release message.
  • the difference between this step and S414a lies in that the base station protects the integrity of the message 4 and encrypts the messages.
  • the base station uses the first key to encrypt the downlink data, uses the second key to perform the integrity protection on the RRC connection release message, and uses the fourth key to encrypt the RRC connection release message, and performs integrity protection and encrypted RRC connection
  • the release message and the encrypted downlink data are carried in message 4 and sent to the terminal.
  • S415b The terminal performs integrity protection check on the RRC connection release message, and decrypts downlink data.
  • the terminal uses the second key to perform integrity protection check on the RRC connection release message, uses the derived fourth key to decrypt the RRC connection release message, and uses the first key to decrypt the downlink data.
  • the terminal may recover SRB2 and DRB after receiving message 4.
  • the terminal sends an instruction for early transmission of downlink data to the access network device (that is, the base station), and the base station can send the downlink data to the terminal together with the RRC message, for example, the RRC message It can be an RRC connection release message.
  • the terminal can receive downlink data without entering the connected state, which can help reduce resource consumption, signaling overhead, and terminal. Power consumption.
  • FIG. 4c shows the third implementation manner of the early downlink data transmission method provided by the embodiment of the present application.
  • the third implementation manner is based on the description of one of the early downlink data transmission methods shown in FIG. 2a. The implementation is described in detail below. The third way.
  • the base station After receiving the context recovery response message sent by the MME, the base station recovers the context information of the terminal.
  • the context information of the terminal recovered by the base station includes the old key (that is, the third key).
  • the third key is used for integrity protection of the RRC connection release message.
  • S414c The base station sends a message 4 (Msg4) to the terminal, and the terminal receives Msg4 sent by the base station.
  • Msg4 message 4
  • This step may refer to S414a.
  • the difference between this step and S414a is that the base station has different procedures for protecting and encrypting the integrity of message 4.
  • the base station may use the method 4 above, that is, the base station carries the second NCC in Msg4, and uses the second NCC to derive the fifth key.
  • the base station uses the third key to perform integrity protection on the RRC connection release message, and uses the fifth key to encrypt the downlink data.
  • the RRC connection release message and the encrypted downlink data that perform the integrity protection are carried in message 4 and sent to terminal.
  • the base station adopts the method 5 above, that is, the base station carries the second NCC in Msg4, and uses the second NCC to derive the fifth key and the sixth key.
  • the base station uses the sixth key to perform integrity protection on the RRC connection release message, and uses the fifth key to encrypt the downlink data.
  • the RRC connection release message and the encrypted downlink data that perform integrity protection are carried in message 4 and sent to terminal.
  • the terminal restores the context information.
  • the context information restored by the terminal includes an old key, that is, a third key.
  • the third key may be used to perform integrity protection check on the RRC connection release message.
  • S416c The terminal performs integrity protection check on the RRC connection release message, and decrypts downlink data.
  • the terminal uses the third key to perform integrity protection check on the RRC connection release message.
  • the terminal obtains the second NCC from the received Msg4, uses the second NCC to derive the fifth key, and uses the fifth key to decrypt the downlink data.
  • the terminal obtains the second NCC from the received Msg4, uses the second NCC to derive the fifth key and the sixth key, and uses the sixth key to perform integrity protection on the RRC connection release message. Check, use the fifth key to decrypt the downlink data.
  • S417c is the same as S417a.
  • the terminal sends an instruction for early transmission of downlink data to the access network device (that is, the base station), and the base station can send the downlink data to the terminal together with the RRC message, for example, the RRC message It can be an RRC connection release message.
  • the terminal can receive downlink data without entering the connected state, which can help reduce resource consumption, signaling overhead, and terminal. Power consumption.
  • FIG. 5a shows the fourth implementation manner of the early downlink data transmission method provided by the embodiment of the present application.
  • the fourth implementation manner is based on the foregoing description of the second downstream data early transmission method shown in FIG. 2b. The implementation is described in detail below. The fourth way.
  • the S-GW sends a downlink data notification message (downlink data notification) to the MME, and the MME receives the downlink data notification message sent by the S-GW.
  • a downlink data notification message downlink data notification
  • the downlink data notification message carries an instruction, and the meaning of the instruction can refer to the description above.
  • the downlink data notification message also carries an identifier of the terminal, for example, the identifier is S-TMSI.
  • the MME After receiving the downlink data notification message sent by the S-GW, the MME sends a paging message to the base station, and the base station receives the paging message (that is, the paging message) sent by the MME.
  • the paging message is used to instruct the base station to page the terminal.
  • the paging message carries the identity of the terminal, for example, the identity is S-TMSI.
  • the paging message also carries an instruction, and the meaning of the instruction can refer to the description above.
  • the base station After receiving the paging message sent by the MME, the base station sends the paging message in a broadcast form.
  • the terminal in the idle state periodically monitors the paging message.
  • the terminal monitors the paging message sent by the base station and confirms that the paging message carries its own identity, the terminal triggers the following steps.
  • S504a is the same as S404a
  • S505a is the same as S405a
  • S506a is the same as S406a, and details are not described herein again.
  • S507a The terminal sends a message 3 (that is, Msg3) to the base station, and the base station receives the Msg3 sent by the terminal.
  • a message 3 that is, Msg3
  • Msg3 may be an RRC connection resume request (RRC connection resume request) message.
  • the RRC connection restoration request message may also carry the following information: a resume identifier (resume ID), a resume cause (resume cause), and a short resume MAC-I.
  • resume ID is used to identify the suspended terminal, that is, to identify the terminal that sent the RRC connection resume request message
  • resumecause is used to indicate the reason for the terminal to resume the connection, for example, the value of resumecause is the called connection (Mobile-terminating-Access, mt-Access), or the value of the resume value is a newly added value, which is used to indicate that the reason for resuming the connection is to transmit a single downlink data
  • short MAC-I is used for Msg3 is integrity protected to prevent tampering with Msg3.
  • the base station After receiving the RRC connection restoration request, the base station sends a UE context recovery request (UE context request) message to the MME according to the instructions carried in the paging message received in S502a, and the MME receives the terminal context restoration request message sent by the base station. .
  • UE context request UE context request
  • the identification information of the terminal carried in the paging message in S502a is S-TMSI, or S-TMSI and Resume ID
  • the identification of the terminal carried in the RRC connection restoration request in S507a is resume ID.
  • the base station determines that the terminal sending the RRC connection restoration request in step S502a is a terminal with a single downlink data, so the base station does not send an RRC connection restoration response message to the terminal, but sends it to the MME.
  • S510a to S517a are the same as S410a to S417a, and are not repeated here.
  • the network side sends an indication of early transmission of downlink data in a downlink data notification message and a paging message, and then the base station may send the downlink data to the terminal together with the RRC message.
  • the RRC message can be an RRC connection release message.
  • the terminal can receive the downlink data without entering the connected state, which can help reduce resource consumption and signaling overhead. Reduce the power consumption of the terminal.
  • FIG. 5b shows the fifth implementation manner of the early downlink data transmission method provided by the embodiment of the present application.
  • the fifth implementation manner is based on the description of the second downstream data early transmission method shown in FIG. 2b. The implementation is described in detail below. The fifth way.
  • S506b is the same as S406b.
  • S507b is the same as S507a.
  • the network side sends an indication of early transmission of downlink data in a downlink data notification message and a paging message, and then the base station may send the downlink data to the terminal together with the RRC message.
  • the RRC message can be an RRC connection release message.
  • the terminal can receive the downlink data without entering the connected state, which can help reduce resource consumption and signaling overhead. Reduce the power consumption of the terminal.
  • FIG. 5c shows a sixth implementation manner of the early downlink data transmission method provided by an embodiment of the present application.
  • the sixth implementation manner is based on the description of the second early downlink data transmission method shown in FIG. 2b. The implementation is described in detail below. Way six.
  • the network side sends an indication of early transmission of downlink data in a downlink data notification message and a paging message, and then the base station may send the downlink data to the terminal together with the RRC message.
  • the RRC message can be an RRC connection release message.
  • the terminal can receive the downlink data without entering the connected state, which can help reduce resource consumption and signaling overhead. Reduce the power consumption of the terminal.
  • FIG. 6a shows the seventh implementation manner of the early downlink data transmission method according to the embodiment of the present application.
  • the seventh implementation manner is based on the description of the third early transmission method of the downlink data shown in FIG. 2c. The implementation is described in detail below. Way Seven.
  • S601a to S606a are the same as S501a to S506a.
  • S607a is the same as S407a.
  • S608a to S617a are the same as S508a to S517a, and are not repeated here.
  • the base station can send a single downlink data to the terminal in the random access process according to the instructions sent by the terminal and the core network equipment, and does not need to establish an RRC connection of the terminal, so that the terminal In the idle state, the downlink data can be completely received, which helps reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • FIG. 6b shows the eighth implementation manner of the early downlink data transmission method provided by the embodiment of the present application.
  • the eighth implementation manner is based on the third description of the early downlink data transmission method shown in FIG. 2c. The implementation is described in detail below. Eighth way.
  • S601b to S606b are the same as S501b to S506b.
  • S607b is the same as S407b.
  • S608b to S616b are the same as S508b to S516b, and are not repeated here.
  • the base station can send a single downlink data to the terminal in the random access process according to the instructions sent by the terminal and the core network equipment, and does not need to establish an RRC connection to the terminal, so that the terminal In the idle state, the downlink data can be completely received, which helps reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • FIG. 6c shows the ninth implementation manner of the early downlink data transmission method according to the embodiment of the present application.
  • the ninth implementation manner is based on the description of the third downlink data early transmission method shown in FIG. 2c. The implementation is described in detail below. Way Nine.
  • S601c to S606c are the same as S501c to S506c.
  • S607c is the same as S407c.
  • S608c to S617c are the same as S508c to S517c, and are not repeated here.
  • the base station can send a single downlink data to the terminal in the random access process according to the instructions sent by the terminal and the core network equipment, and does not need to establish the RRC connection of the terminal, so that the terminal In the idle state, the downlink data can be completely received, which helps reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • FIG. 7a shows the tenth implementation manner of the early downlink data transmission method provided by the embodiment of the present application.
  • the tenth implementation manner is based on the description of the fourth downlink data early transmission method shown in FIG. 3a. The implementation is described in detail below. Ten of ways.
  • the S-GW sends a downlink data notification message (downlink data notification) to the MME, and the MME receives the downlink data notification message sent by the S-GW.
  • a downlink data notification message downlink data notification
  • the downlink data notification message carries an identifier of the terminal, for example, the identifier is S-TMSI.
  • the MME After receiving the downlink data notification message sent by the S-GW, the MME sends a paging message to the base station.
  • the base station receives a paging message (ie, a paging message) sent by the MME, and the paging message is used to instruct the base station to page the terminal.
  • a paging message ie, a paging message
  • S703a After receiving the paging message sent by the MME, the base station sends the paging message in a broadcast form.
  • the terminal in the idle state periodically monitors the paging message.
  • the terminal monitors the paging message sent by the base station and confirms that the paging message carries its own identity, the terminal triggers the following steps.
  • S704a The terminal sends a random access preamble to the base station, and the base station receives the random access preamble sent by the terminal.
  • the base station broadcasts several random access preambles to all terminals through a broadcast message.
  • the terminal randomly selects one of the random access preambles broadcasted by the base station, and broadcasts the random access preambles broadcasted by the base station.
  • a resource is randomly selected from the resources, and the selected random access preamble is sent on the selected resource.
  • S705a The base station sends a random access response (RAR) to the terminal, and the terminal receives the random access response sent by the base station.
  • RAR random access response
  • the base station monitors the random access preamble sent by the terminal on the resources of the random access preamble, and sends a RAR to the terminal when a random access preamble is detected.
  • the RAR includes: timing (advanced, TA) of the terminal sending Msg3 and uplink resource (UL grant) of the terminal sending Msg3.
  • RRC data early request RRC data early request
  • the base station receives the RRC data early transmission request message from the terminal.
  • the RRC data early transmission request message carries an indication, which is recorded as a first indication.
  • the meaning of the first indication may be single packet or single DL data, or it may be indicated by dedicated Info NAS, where the original function of dedicated Info NAS is to carry uplink data for early transmission.
  • the RRC data early transmission request message is used to notify the downlink data of early transmission. Therefore, the dedicated InfoInfo NAS can be set to NULL to indicate that no uplink data is carried, and it is further indicated that the downlink data is early. pass.
  • the RRC early data request message may also carry other information, and the other information carried in the message is the same as in the prior art.
  • S707a The base station sends a terminal initialization (Initial UE Message) message to the MME, and the MME receives the terminal initialization message from the base station.
  • Terminal initialization Initial UE Message
  • the terminal initialization message is used to initialize context information of the terminal.
  • the terminal initialization message carries an instruction, which is recorded as a second instruction, and the meaning of the instruction of the second instruction is the same as the explanation of the instruction in this article.
  • the S-GW sends downlink data to the MME, and the MME receives the downlink data sent by the S-GW.
  • the MME encapsulates the downlink data in the NAS message.
  • the MME sends the downlink data to the base station through a downlink NAS transmission (DL NAS transport), and the base station receives the NAS message from the MME.
  • DL NAS transport downlink NAS transmission
  • S711a The base station sends an RRC data early complete message to the terminal, and the terminal receives an RRC data early complete message from the base station.
  • the RRC data early complete (RRC data early) message carries downlink data.
  • the base station encapsulates the received NAS message in an RRC data early completion message and sends it to the terminal.
  • the terminal obtains the NAS message from the received RRCearly data complete message, thereby obtaining downlink data.
  • the MME can encapsulate the downlink data of the terminal in a NAS message and send it to the terminal via the base station according to the instruction sent by the terminal. There is no need to establish an RRC connection of the terminal, so that the terminal is in an idle state After receiving the downlink data, this helps reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • FIG. 7b shows the eleventh implementation manner of the early downlink data transmission method provided by the embodiment of the present application.
  • the eleventh implementation manner is based on the description of the fourth early downlink data transmission method shown in FIG. The eleventh implementation method.
  • S701b to S705b are the same as S701a to S705a.
  • S701a to S705a For details, refer to the description of related steps above, and details are not described herein again.
  • S706b The terminal sends an RRC connection request message to the base station, which is used to request establishment of an RRC connection.
  • the base station receives an RRC connection request message from the terminal.
  • the RRC connection request message carries a first instruction.
  • the meaning of the first indication may be single packet or single DL data.
  • S707b to S711b are the same as S707a to S711a.
  • S707a to S711a For details, refer to the description of the relevant steps above, and details are not described herein again.
  • the MME can encapsulate the downlink data of the terminal in a NAS message and send it to the terminal via the base station according to the instruction sent by the terminal. There is no need to establish the RRC connection of the terminal, so that the terminal is idle. The state can finish receiving the downlink data, which helps to reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • FIG. 7c shows a twelfth implementation manner of the early downlink data transmission method according to an embodiment of the present application.
  • the twelfth implementation manner is based on the description of the fourth downlink data early transmission method shown in FIG. 3a, which is described in detail below.
  • S701c to S705c are the same as S701a to S705a. Please refer to the description of the relevant steps above, which will not be repeated here.
  • the terminal sends an RRC connection request (RRC connection request) message to the base station, which is used to request establishment of an RRC connection.
  • the RRC connection request message carries a first instruction.
  • the meaning of the first indication may be single packet or single DL data.
  • S707c to S710c are the same as S707a to S710a.
  • S707a to S710a For details, refer to the description of the relevant steps above, and details are not described herein again.
  • S711c The base station sends an RRC connection release message to the terminal, and the terminal receives the RRC connection release message from the base station.
  • the RRC connection release message (RRC connection release) carries downlink data. Specifically, the base station encapsulates the received NAS message in an RRC connection release message and sends it to the terminal. The terminal obtains the NAS message from the received RRC connection release message, thereby obtaining downlink data.
  • the MME can encapsulate the downlink data of the terminal in a NAS message and send it to the terminal via the base station according to the instruction sent by the terminal. There is no need to establish the RRC connection of the terminal, which makes the terminal idle. The state can finish receiving the downlink data, which helps to reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • FIG. 8a illustrates a thirteenth implementation manner of the early downlink data transmission method provided by an embodiment of the present application.
  • the thirteenth implementation manner is based on the description of the fifth early downlink data transmission method shown in FIG. 3b, which is described in detail below.
  • the thirteenth implementation is based on the description of the fifth early downlink data transmission method shown in FIG. 3b, which is described in detail below. The thirteenth implementation.
  • the S-GW sends a downlink data notification message (downlink data notification) to the MME, and the MME receives the downlink data notification message sent by the S-GW.
  • a downlink data notification message downlink data notification
  • the downlink data notification message carries an instruction, and the meaning of the instruction can refer to the description above.
  • the downlink data notification message also carries an identifier of the terminal, for example, the identifier is S-TMSI.
  • the MME sends a paging message to the base station after receiving the downlink data notification message sent by the S-GW, and the base station receives the paging message (that is, the paging message) sent by the MME.
  • the paging message is used to instruct the base station to page the terminal.
  • the paging message carries the identity of the terminal, for example, the identity is S-TMSI.
  • the paging message also carries an instruction, and the meaning of the instruction can refer to the description above.
  • an indication may also be carried in the paging message sent in this step, and the meaning of the indication may refer to the description above.
  • the terminal in the idle state periodically monitors the paging message.
  • the terminal monitors the paging message sent by the base station and confirms that the paging message carries its own identity, the terminal triggers the following steps.
  • S804a The terminal sends a random access preamble to the base station, and the base station receives the random access preamble sent by the terminal.
  • the base station broadcasts several random access preambles to all terminals through a broadcast message.
  • the terminal randomly selects one of the random access preambles broadcasted by the base station, and broadcasts the random access preambles broadcasted by the base station.
  • a resource is randomly selected from the resources, and the selected random access preamble is sent on the selected resource.
  • S805a The base station sends a random access response (RAR) to the terminal, and the terminal receives the random access response sent by the base station.
  • RAR random access response
  • the base station monitors the random access preamble sent by the terminal on the resources of the random access preamble, and sends a RAR to the terminal when a random access preamble is detected.
  • the RAR includes: timing (advanced, TA) of the terminal sending Msg3 and uplink resource (UL grant) of the terminal sending Msg3.
  • the terminal sends an RRC data early request (RRC data early request) message to the base station, and the base station receives the RRC data early transmission request message from the terminal.
  • RRC data early request RRC data early request
  • the RRC data early request (RRC data early request) message is used to request the early transmission of uplink data.
  • the RRC data early transmission request message may carry dedicated NAS Info.
  • the original function of the NAS is to carry the uplink data transmitted early.
  • the dedicated InfoInfo NAS can be set to empty NULL to indicate that no uplink data is carried.
  • S807a The base station sends a terminal initialization (Initial UE Message) message to the MME, and the MME receives the terminal initialization message from the base station.
  • Terminal initialization Initial UE Message
  • the S-GW sends downlink data to the MME, and the MME receives the downlink data sent by the S-GW.
  • the MME encapsulates the downlink data in the NAS message, the MME sends the downlink data to the base station through a downlink NAS transmission (DL NAS transport), and the base station receives the NAS message from the MME.
  • DL NAS transport downlink NAS transmission
  • the base station sends an RRC early data complete (RRC data complete) message to the terminal, and the terminal receives an RRC early data complete message from the base station.
  • RRC data complete RRC early data complete
  • the RRC data early complete (RRC data early) message carries downlink data.
  • the base station encapsulates the received NAS message in an RRC data early completion message and sends it to the terminal.
  • the terminal obtains the NAS message from the received RRCearly data complete message, thereby obtaining downlink data.
  • the MME can encapsulate the downlink data of the terminal in a NAS message and send it to the terminal via the base station according to the instruction sent by the SGW.
  • the RRC connection of the terminal does not need to be established, so that the terminal is idle.
  • the state can finish receiving the downlink data, which helps to reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • FIG. 8b shows the fourteenth implementation manner of the early downlink data transmission method according to the embodiment of the present application.
  • the fourteenth implementation manner is based on the description of the fifth early downlink data transmission method shown in FIG. 3b, which is described in detail below. Fourteenth of this implementation.
  • S801b to S805b are the same as S801a to S805a.
  • S801a to S805a For details, refer to the description of related steps above, and details are not described herein again.
  • S806b The terminal sends an RRC connection request message to the base station, which is used to request establishment of an RRC connection.
  • the base station receives an RRC connection request message from the terminal.
  • S807b to S811b are the same as S807a to S811a.
  • S807a to S811a For details, refer to the description of related steps above, and details are not described herein again.
  • the MME can encapsulate the downlink data of the terminal in a NAS message and send it to the terminal via the base station according to the instruction sent by the SGW. There is no need to establish the RRC connection of the terminal, which makes the terminal idle. The state can finish receiving the downlink data, which helps to reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • FIG. 8c shows a fifteenth implementation manner of an early downlink data transmission method according to an embodiment of the present application.
  • the fifteenth implementation manner is based on the description of the fifth early downlink data transmission method shown in FIG. 3b, which is described in detail below. Fifteen of the implementation.
  • S801c to S805c are the same as S801a to S805a.
  • S801a to S805a For details, refer to the description of the relevant steps above, and details are not described herein again.
  • the terminal sends an RRC connection request (RRC connection request) message to the base station, which is used to request establishment of an RRC connection.
  • RRC connection request RRC connection request
  • S807c to S810c are the same as S807a to S810a.
  • S807a to S810a For details, refer to the description of the relevant steps above, and details are not described herein again.
  • the base station sends an RRC connection release message to the terminal, and the terminal receives the RRC connection release message from the base station.
  • the RRC connection release message (RRC connection release) carries downlink data. Specifically, the base station encapsulates the received NAS message in an RRC connection release message and sends it to the terminal. The terminal obtains the NAS message from the received RRC connection release message, thereby obtaining downlink data.
  • the MME can encapsulate the downlink data of the terminal in a NAS message and send it to the terminal via the base station according to the instruction sent by the SGW.
  • the RRC connection of the terminal does not need to be established, so that the terminal is idle.
  • the state can finish receiving the downlink data, which helps to reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • FIG. 9a shows the sixteenth implementation manner of the early downlink data transmission method according to the embodiment of the present application.
  • the sixteenth implementation manner is based on the description of the sixth early downlink data transmission method shown in FIG. 3c.
  • the S-GW sends a downlink data notification message (downlink data notification) to the MME, and the MME receives the downlink data notification message sent by the S-GW.
  • a downlink data notification message downlink data notification
  • the downlink data notification message carries an instruction, and the meaning of the instruction can refer to the description above.
  • the downlink data notification message also carries an identifier of the terminal, for example, the identifier is S-TMSI.
  • the MME After receiving the downlink data notification message sent by the S-GW, the MME sends a paging message to the base station, and the base station receives the paging message (that is, the paging message) sent by the MME.
  • the paging message is used to instruct the base station to page the terminal.
  • the paging message carries the identity of the terminal, for example, the identity is S-TMSI.
  • S903a After receiving the paging message sent by the MME, the base station sends the paging message in a broadcast form.
  • an indication may also be carried in the paging message sent in this step, and the meaning of the indication may refer to the description above.
  • the terminal in the idle state periodically monitors the paging message.
  • the terminal monitors the paging message sent by the base station and confirms that the paging message carries its own identity, the terminal triggers the following steps.
  • S904a The terminal sends a random access preamble to the base station, and the base station receives the random access preamble sent by the terminal.
  • the base station broadcasts several random access preambles to all terminals through a broadcast message.
  • the terminal randomly selects one of the random access preambles broadcasted by the base station, and broadcasts the random access preambles broadcasted by the base station.
  • a resource is randomly selected from the resources, and the selected random access preamble is sent on the selected resource.
  • the base station sends a random access response (RAR) to the terminal, and the terminal receives the random access response sent by the base station.
  • RAR random access response
  • the base station monitors the random access preamble sent by the terminal on the resources of the random access preamble, and sends a RAR to the terminal when a random access preamble is detected.
  • the RAR includes: timing (advanced, TA) of the terminal sending Msg3 and uplink resource (UL grant) of the terminal sending Msg3.
  • RRC data early request RRC data early request
  • the base station receives the RRC data early transmission request message from the terminal.
  • the RRC data early request (RRC data early request) message is used to request the early transmission of uplink data.
  • the RRC data early transmission request message may carry dedicated NAS Info.
  • the original function of the NAS is to carry the uplink data transmitted early.
  • the dedicated InfoInfo NAS can be set to empty NULL to indicate that no uplink data is carried.
  • S907a The base station sends a context recovery request (UE context request) message to the MME, and the MME receives the context recovery request message from the base station.
  • UE context request UE context request
  • the S-GW sends downlink data to the MME, and the MME receives the downlink data sent by the S-GW.
  • the MME encapsulates the downlink data in the NAS message, the MME sends the downlink data to the base station through a downlink NAS transmission (DL NAS transport), and the base station receives the NAS message from the MME.
  • DL NAS transport downlink NAS transmission
  • the NAS message also carries an indication.
  • indication For the meaning of the indication, refer to the description above.
  • S911a The base station sends an RRC early data complete message to the terminal, and the terminal receives an RRC early data complete message from the base station.
  • the RRC data early complete (RRC data early) message carries downlink data.
  • the base station encapsulates the received NAS message in an RRC data early completion message and sends it to the terminal.
  • the terminal obtains the NAS message from the received RRCearly data complete message, thereby obtaining downlink data.
  • the MME can encapsulate the downlink data of the terminal in a NAS message and send it to the terminal via the base station according to the instruction sent by the SGW.
  • the RRC connection of the terminal does not need to be established, and the terminal is idle.
  • the state can finish receiving the downlink data, which helps to reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • FIG. 9b shows the seventeenth implementation manner of the early downlink data transmission method according to the embodiment of the present application.
  • the seventeenth implementation manner is based on the description of the sixth early downlink data transmission method shown in FIG. 3c, which is described in detail below. Seventeenth of the implementation.
  • S901b to S905b are the same as S901a to S905a.
  • S901a to S905a For details, refer to the description of related steps above, and details are not described herein again.
  • S906b The terminal sends an RRC connection request message to the base station, which is used to request establishment of an RRC connection.
  • the base station receives an RRC connection request message from the terminal.
  • S907b to S911b are the same as S907a to S911a.
  • S907a to S911a For details, refer to the description of related steps above, and details are not described herein again.
  • the MME can encapsulate the downlink data of the terminal in a NAS message and send it to the terminal via the base station according to the instruction sent by the SGW. There is no need to establish an RRC connection of the terminal, so that the terminal is idle The state can finish receiving the downlink data, which helps to reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • FIG. 9c shows an eighteenth implementation manner of an early downlink data transmission method according to an embodiment of the present application.
  • the eighteenth implementation manner is based on the description of the sixth early downlink data transmission method shown in FIG. 3c, and is described in detail below. Eighteenth of the implementation.
  • S901c to S905c are the same as S901a to S905a.
  • S901a to S905a For details, refer to the description of the relevant steps above, and details are not described herein again.
  • RRC connection request RRC connection request
  • the terminal sends an RRC connection request (RRC connection request) message to the base station, which is used to request establishment of an RRC connection.
  • S907c to S910c are the same as S907a to S910a.
  • S911c The base station sends an RRC connection release message to the terminal, and the terminal receives the RRC connection release message from the base station.
  • the RRC connection release message (RRC connection release) carries downlink data. Specifically, the base station encapsulates the received NAS message in an RRC connection release message and sends it to the terminal. The terminal obtains the NAS message from the received RRC connection release message, thereby obtaining downlink data.
  • the MME can encapsulate the downlink data of the terminal in a NAS message and send it to the terminal via the base station according to the instruction sent by the SGW.
  • the RRC connection of the terminal does not need to be established, and the terminal is idle.
  • the state can finish receiving the downlink data, which helps to reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • FIG. 10a shows the nineteenth implementation manner of the early downlink data transmission method provided by the embodiment of the present application.
  • the nineteenth implementation manner is based on the foregoing description of the seventh method of early downlink data transmission shown in FIG. 3d, which is described in detail below. Nineteen of this implementation.
  • the S-GW sends a downlink data notification message (downlink data notification) to the MME, and the MME receives the downlink data notification message sent by the S-GW.
  • a downlink data notification message downlink data notification
  • the downlink data notification message also carries an identifier of the terminal, for example, the identifier is S-TMSI.
  • the MME After receiving the downlink data notification message sent by the S-GW, the MME sends a paging message to the base station, and the base station receives the paging message (that is, the paging message) sent by the MME.
  • the paging message is used to instruct the base station to page the terminal.
  • the paging message carries the identity of the terminal, for example, the identity is S-TMSI.
  • the base station After receiving the paging message sent by the MME, the base station sends the paging message in a broadcast form.
  • an indication may also be carried in the paging message sent in this step, and the meaning of the indication may refer to the description above.
  • the terminal in the idle state periodically monitors the paging message.
  • the terminal monitors the paging message sent by the base station and confirms that the paging message carries its own identity, the terminal triggers the following steps.
  • S1004a The terminal sends a random access preamble to the base station, and the base station receives the random access preamble sent by the terminal.
  • the base station broadcasts several random access preambles to all terminals through a broadcast message.
  • the terminal randomly selects one of the random access preambles broadcasted by the base station, and broadcasts the random access preambles broadcasted by the base station.
  • a resource is randomly selected from the resources, and the selected random access preamble is sent on the selected resource.
  • S1005a The base station sends a random access response (RAR) to the terminal, and the terminal receives the random access response sent by the base station.
  • RAR random access response
  • the base station monitors the random access preamble sent by the terminal on the resources of the random access preamble, and sends a RAR to the terminal when a random access preamble is detected.
  • the RAR includes: timing (advanced, TA) of the terminal sending Msg3 and uplink resource (UL grant) of the terminal sending Msg3.
  • RRC data early request RRC data early request
  • the base station receives the RRC data early transmission request message from the terminal.
  • the RRC data early request (RRC data early request) message is used to request the early transmission of uplink data.
  • the RRC data early transmission request message may carry dedicated NAS Info.
  • the original function of the NAS is to carry the uplink data transmitted early.
  • the dedicated InfoInfo NAS can be set to empty NULL to indicate that no uplink data is carried.
  • S1007a The base station sends a context recovery request (UE context request) message to the MME, and the MME receives the context recovery request message from the base station.
  • UE context request UE context request
  • the S-GW sends downlink data to the MME, and the MME receives the downlink data sent by the S-GW.
  • the downlink data carries an instruction, and the meaning of the instruction may refer to the description above.
  • the MME encapsulates the downlink data in the NAS message, the MME sends the downlink data to the base station through a downlink NAS transmission (DL NAS transport), and the base station receives the NAS message from the MME.
  • DL NAS transport downlink NAS transmission
  • the NAS message also carries an indication.
  • indication For the meaning of the indication, refer to the description above.
  • S1011a The base station sends an RRC early data complete (RRC data complete) message to the terminal, and the terminal receives an RRC early data complete message from the base station.
  • RRC data complete RRC early data complete
  • the RRC data early complete (RRC data early) message carries downlink data.
  • the base station encapsulates the received NAS message in an RRC data early completion message and sends it to the terminal.
  • the terminal obtains the NAS message from the received RRCearly data complete message, thereby obtaining downlink data.
  • the MME can encapsulate the downlink data of the terminal in a NAS message and send it to the terminal via the base station according to the instruction sent by the SGW.
  • the RRC connection of the terminal does not need to be established, so that the terminal is idle.
  • the state can finish receiving the downlink data, which helps to reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • FIG. 10b shows the implementation method 20 of the early downlink data transmission method provided by the embodiment of the present application.
  • the implementation method 20 is based on the description of the seventh method of the early transmission of downlink data shown in FIG. 3d. The details are described below.
  • S1001b to S1005b are the same as S1001a to S1005a.
  • S1001a to S1005a For details, refer to the description of related steps above, and details are not described herein again.
  • S1006b The terminal sends an RRC connection request message to the base station, which is used to request establishment of an RRC connection.
  • the base station receives an RRC connection request message from the terminal.
  • S1007b to S1011b are the same as S1007a to S1011a.
  • S1007a to S1011a For details, refer to the description of related steps above, and details are not described herein again.
  • the MME can encapsulate the downlink data of the terminal in a NAS message and send it to the terminal via the base station according to the instruction sent by the SGW.
  • the RRC connection of the terminal does not need to be established, so that the terminal is idle.
  • the state can finish receiving the downlink data, which helps to reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • FIG. 10c shows a twenty-first implementation manner of the downlink data early transmission method according to an embodiment of the present application.
  • the twenty-first implementation manner is based on the description of the seventh downlink data early transmission method shown in FIG. Introduce the 21st way of this implementation.
  • S1001c to S1005c are the same as S1001a to S1005a.
  • S1001a to S1005a For details, refer to the description of the relevant steps above, which will not be repeated here.
  • RRC connection request RRC connection request
  • the terminal sends an RRC connection request (RRC connection request) message to the base station, which is used to request establishment of an RRC connection.
  • S1007c to S1010c are the same as S1007a to S1010a.
  • S1007a to S1010a For details, refer to the description of related steps above, and details are not described herein again.
  • S1011c The base station sends an RRC connection release message to the terminal, and the terminal receives the RRC connection release message from the base station.
  • the RRC connection release message (RRC connection release) carries downlink data. Specifically, the base station encapsulates the received NAS message in an RRC connection release message and sends it to the terminal. The terminal obtains the NAS message from the received RRC connection release message, thereby obtaining downlink data.
  • the MME can encapsulate the downlink data of the terminal in a NAS message and send it to the terminal via the base station according to the instruction sent by the SGW. There is no need to establish the RRC connection of the terminal, so that the terminal can In the idle state, the downlink data can be completely received, which helps reduce resource consumption, signaling overhead, and power consumption of the terminal.
  • an embodiment of the present application provides a downlink data early transmission device 1100.
  • the downlink data early transmission device 1100 may be applicable to the communication system shown in FIG. The function of the terminal in the example.
  • FIG. 11 shows only the main components of the terminal.
  • the terminal 1100 includes a processor, a memory, a control circuit, an antenna, and an input / output device.
  • the processor is mainly used for processing communication protocols and communication data, and controlling the entire terminal, executing software programs, and processing software program data.
  • the processor is used to support the terminal to perform the actions described in the foregoing method embodiments, such as generating
  • the first instruction sends a message 3 to the network device, the message 3 carries the first instruction, and the message 4 is received from the network device.
  • the memory is mainly used to store software programs and data, such as storing the first instruction and downlink data described in the foregoing embodiment.
  • the control circuit is mainly used for conversion of baseband signals and radio frequency signals and processing of radio frequency signals.
  • the control circuit and the antenna together can also be called a transceiver, which is mainly used to send and receive radio frequency signals in the form of electromagnetic waves.
  • Input / output devices such as a touch screen, a display screen, and a keyboard, are mainly used to receive data input by the user and output data to the user.
  • the processor can read the software program in the storage unit, interpret and execute the instructions of the software program, and process the data of the software program.
  • the processor performs baseband processing on the data to be sent, and then outputs the baseband signal to the radio frequency circuit.
  • the radio frequency circuit processes the baseband signal, the radio frequency signal is sent out in the form of electromagnetic waves through the antenna.
  • the RF circuit receives the RF signal through the antenna, converts the RF signal into a baseband signal, and outputs the baseband signal to the processor.
  • the processor converts the baseband signal into data and processes the data.
  • FIG. 11 shows only one memory and one processor. In an actual terminal, there may be multiple processors and multiple memories.
  • the memory may also be referred to as a storage medium or a storage device, which is not limited in the embodiments of the present application.
  • the processor may include a baseband processor and / or a central processor.
  • the baseband processor is mainly used to process communication protocols and communication data
  • the central processor is mainly used to control the entire terminal. Execute the software program and process the data of the software program.
  • the processor in FIG. 11 may integrate the functions of the baseband processor and the central processing unit.
  • the baseband processor and the central processing unit may also be independent processors, which are interconnected through technologies such as a bus.
  • the terminal may include multiple baseband processors to adapt to different network standards, the terminal may include multiple central processors to enhance its processing capabilities, and various components of the terminal may be connected through various buses.
  • the baseband processor may also be expressed as a baseband processing circuit or a baseband processing chip.
  • the central processing unit may also be expressed as a central processing circuit or a central processing chip.
  • the function of processing communication protocols and communication data may be built in the processor or stored in the storage unit in the form of a software program, and the processor executes the software program to implement the baseband processing function.
  • the antenna and the control circuit having the transmitting and receiving function may be regarded as the transmitting and receiving unit 1101 of the terminal 1100, for example, for supporting the terminal to perform the receiving function and the transmitting function according to the foregoing method embodiment.
  • a processor having a processing function is regarded as a processing unit 1102 of the terminal device 1100.
  • the terminal 1100 includes a transceiver unit 1101 and a processing unit 1102.
  • the transceiver unit may also be referred to as a transceiver, a transceiver, a transceiver device, and the like.
  • the device for implementing the receiving function in the transceiver unit 1101 can be regarded as a receiving unit, and the device for implementing the transmitting function in the transceiver unit 1101 can be regarded as a transmitting unit, that is, the transceiver unit 1101 includes a receiving unit and a transmitting unit.
  • the receiving unit may also be called a receiver, an input port, a receiving circuit, etc.
  • the sending unit may be called a transmitter, a transmitter, or a transmitting circuit.
  • the processor 1102 may be configured to execute instructions stored in the memory, to control the transceiver unit 1101 to receive signals and / or send signals to complete functions of the terminal in the foregoing method embodiments.
  • the function of the transceiver unit 1101 may be considered to be implemented by a transceiver circuit or a dedicated chip for transceiver.
  • FIG. 12 is a schematic structural diagram of an apparatus for early transmission of downlink data according to an embodiment of the present application.
  • the apparatus may be a schematic structural diagram of an access network device (that is, a base station).
  • the access network device may be applied to the system shown in FIG. 1, and performs the function of the first network device in the foregoing method embodiment.
  • the network device 1200 (also referred to as a base station 1200) may include one or more radio frequency units, such as a remote radio unit (RRU) 1201 and one or more baseband units (BBUs) (also referred to as Is a digital unit, digital unit (DU) 1202.
  • RRU remote radio unit
  • BBUs baseband units
  • Is digital unit, digital unit (DU) 1202.
  • the RRU 1201 may be referred to as a transceiver unit, a transceiver, a transceiver circuit, or a transceiver, etc., and may include at least one antenna 12011 and a radio frequency unit 12012.
  • the RRU 1201 part is mainly used for receiving and transmitting radio frequency signals and converting radio frequency signals to baseband signals, for example, for receiving instructions sent by a terminal, receiving instructions sent by a second network device, or sending downlink data to a terminal.
  • the 1202 part of the BBU is mainly used for baseband processing and controlling base stations.
  • the RRU 1201 and the BBU 1202 may be physically located together or physically separated, that is, a distributed base station.
  • the BBU 1202 is a control center of a base station, and may also be referred to as a processing unit, which is mainly used to complete baseband processing functions, such as channel coding, multiplexing, modulation, spreading, and so on.
  • the BBU (Processing Unit) 1202 may be used to control a base station to execute the operation process related to the first network device in the foregoing method embodiment.
  • the BBU 1202 may be composed of one or more boards, and multiple boards may jointly support a single access indication wireless access network (such as an LTE network), or may separately support different access systems. Wireless access network (such as LTE network, 12G network or other networks).
  • the BBU 1202 further includes a memory 12021 and a processor 12022.
  • the memory 12021 is configured to store necessary instructions and data.
  • the memory 12021 stores the correspondence between the codebook index and the precoding matrix in the foregoing embodiment.
  • the processor 12022 is configured to control the base station to perform a necessary action, for example, to control the base station to perform an operation process on the first network device in the foregoing method embodiment.
  • the memory 12021 and the processor 12022 may serve one or more single boards. That is, the memory and processor can be set separately on each board. It is also possible that multiple boards share the same memory and processor. In addition, the necessary circuits can be set on each board.
  • an embodiment of the present application further provides a downlink data early transmission device 1300, which is used to implement the second network in the foregoing embodiment.
  • the operations performed by the device (that is, the first core network device) and the third network device (that is, the second core network device) are shown for simplicity. It is illustrated in FIG. 13, and it can be understood that FIG. 13 is only a schematic diagram, and can be applied to the first core network device and the second core network device.
  • the downlink data early transmission device 1300 includes a transceiver 1301, a processor 1302, and a memory 1303.
  • the processor 1302 is configured to call a group of programs, and when the programs are executed, cause the processor 1302 to perform operations performed by the second network device and the third network device in one of the communication methods provided in the foregoing embodiments.
  • the memory 1303 is configured to store a program executed by the processor 1302.
  • the transceiver 1301 may be regarded as a transceiver unit of the second network device / the third network device, and is configured to support the second network device / the third network device to perform the receiving function and the sending function described in the foregoing method embodiment.
  • the processor 1302 may be regarded as a processing unit of the second network device / third network device.
  • a device that implements the receiving function in the transceiver unit can be regarded as a receiving unit, and a device that the transceiver unit uses to implement the transmitting function can be regarded as a transmitting unit.
  • the transmitting and receiving unit includes a receiving unit and a transmitting unit, and the receiving unit can also It is called a receiver, an input port, a receiving circuit, etc., and a transmitting unit may be called a transmitter, a transmitter, or a transmitting circuit.
  • the present application also provides a communication system including one or more of the aforementioned network devices, and one or more terminals.
  • the processor in the embodiment of the present application may be an integrated circuit chip and has a signal processing capability.
  • each step of the foregoing method embodiment may be completed by using an integrated logic circuit of hardware in a processor or an instruction in a form of software.
  • the above processor may be a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), an off-the-shelf programmable gate array (FPGA), or other programmable Programming logic devices, discrete gate or transistor logic devices, discrete hardware components.
  • DSP digital signal processor
  • ASIC application specific integrated circuit
  • FPGA off-the-shelf programmable gate array
  • a general-purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
  • the steps of the method disclosed in combination with the embodiments of the present application may be directly implemented by a hardware decoding processor, or may be performed by using a combination of hardware and software modules in the decoding processor.
  • the software module may be located in a mature storage medium such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, and the like.
  • the storage medium is located in a memory, and the processor reads the information in the memory and completes the steps of the foregoing method in combination with its hardware.
  • the memory in the embodiment of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memory.
  • the non-volatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (erasable PROM, EPROM), electrical memory Erase programmable read-only memory (EPROM, EEPROM) or flash memory.
  • the volatile memory may be a random access memory (RAM), which is used as an external cache.
  • RAM random access memory
  • DRAM dynamic random access memory
  • SDRAM synchronous dynamic random access memory
  • double SDRAM double SDRAM
  • DDR SDRAM double data rate synchronous dynamic random access memory
  • enhanced SDRAM enhanced SDRAM
  • SLDRAM synchronous connection dynamic random access memory
  • direct RAMbus RAM direct RAMbus RAM
  • An embodiment of the present application further provides a computer-readable medium having a computer program stored thereon.
  • the computer program is executed by a computer, the method described in any one of the foregoing method embodiments is implemented.
  • the embodiment of the present application further provides a computer program product, and when the computer program product is executed by a computer, the method described in any one of the method embodiments is implemented.
  • the computer program product includes one or more computer instructions.
  • the computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.
  • the computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be from a website site, computer, server, or data center Transmission to another website site, computer, server or data center via wired (such as coaxial cable, optical fiber, Digital Subscriber Line (DSL)) or wireless (such as infrared, wireless, microwave, etc.).
  • the computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, a data center, and the like that includes one or more available medium integration.
  • the available medium may be a magnetic medium (for example, a floppy disk, a hard disk, a magnetic tape), an optical medium (for example, a high density digital video disc (DVD)), or a semiconductor medium (for example, a solid state disk (Solid State Disk, SSD)) and so on.
  • a magnetic medium for example, a floppy disk, a hard disk, a magnetic tape
  • an optical medium for example, a high density digital video disc (DVD)
  • DVD high density digital video disc
  • semiconductor medium for example, a solid state disk (Solid State Disk, SSD)
  • An embodiment of the present application further provides a processing apparatus including a processor and an interface; the processor is configured to execute the communication method according to any one of the foregoing method embodiments.
  • the processing device may be a chip, and the processor may be implemented by hardware or software.
  • the processor may be a logic circuit, an integrated circuit, etc .; when implemented by software
  • the processor may be a general-purpose processor, which is implemented by reading software codes stored in a memory, and the memory may be integrated in the processor, may be located outside the processor, and exist independently.
  • an embodiment or “an embodiment” mentioned throughout the specification means that a particular feature, structure, or characteristic related to the embodiment is included in at least one embodiment of the present application.
  • the appearances of "in one embodiment” or “in an embodiment” appearing throughout the specification are not necessarily referring to the same embodiment.
  • the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. It should be understood that, in the various embodiments of the present application, the size of the sequence numbers of the above processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not deal with the embodiments of the present application.
  • the implementation process constitutes any limitation.
  • this application may be provided as a method, a system, or a computer program product. Therefore, this application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, this application may take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.
  • computer-usable storage media including, but not limited to, disk storage, CD-ROM, optical storage, etc.
  • These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to work in a particular manner such that the instructions stored in the computer-readable memory produce a manufactured article including an instruction device, the instructions
  • the device implements the functions specified in one or more flowcharts and / or one or more blocks of the block diagram.
  • These computer program instructions can also be loaded on a computer or other programmable data processing device, so that a series of steps can be performed on the computer or other programmable device to produce a computer-implemented process, and the The instructions provide steps for implementing the functions specified in one or more flowcharts and / or one or more blocks of the block diagrams.

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Abstract

一种下行数据早传方法及装置，用以实现下行数据早传，提高资源利用效率，降低终端的功耗。该方法为：向网络设备发送随机接入前导码；从所述网络设备接收随机接入响应；响应于所述随机接入响应，向所述网络设备发送消息3，所述消息3携带第一指示，所述第一指示用于指示单个下行数据包；从所述网络设备接收消息4，所述消息4携带下行数据。

Description

一种下行数据早传方法及装置 技术领域
本申请涉及通信技术领域，特别涉及一种下行数据早传方法及装置。
背景技术
在一些通信技术中，当网络侧没有终端的下行数据传输时，基站与终端之间不会建立无线资源控制(radio resource control，RRC)连接，此时终端处于空闲状态，空闲状态即IDLE态。当网络侧有终端的下行数据传输时，网络侧向终端发起寻呼，与终端建立RRC连接，终端从空闲态进入到连接态。网络侧向终端发起寻呼并建立RRC连接的过程需要多条信令的交互才能完成。终端监听到寻呼消息且确定寻呼消息中携带自己的标识时，触发RRC连接建立流程，完成终端的随机接入过程。在随机接入过程完毕之后，网络侧还需要设置终端的上下文以及配置终端的承载，才能发送下行数据。可以看出，当网络侧有终端的下行数据时，需要经过很复杂的过程，需要一定的信令开销。
对类似于机器类型通信(machine type communication，MTC)和窄带物联网(narrow band internet of thing，NB-IoT)等一些通信场景，其数据传输的特点是，数据量较小，且数据到达时间不确定。若按照上述数据传输的方法来传输数据量小的小数据包，会使得无线资源的利用效率降低，大量资源用于RRC连接建立的流程，少量资源用于数据传输。另外，对于MTC类型的终端的应用场景，例如水表、电表等，终端的信号覆盖强度无法满足信号接收要求，因此对MTC进行增强，使基站和终端能够支持扩展覆盖(coverage enhancement)，目前实现扩展覆盖的主要方法是重复多次发送上行或下行信号，通过多次接收合并实现提高数据接收成功率的目的。若小数据包对时延的要求较高，通过上述数据传输的方法和重复发送的方法，无法满足小数据包对时延的要求。
综上，传输小数据量的下行数据包，若使用繁琐的RRC连接建立过程，系统开销过大，资源利用效率低下，终端的功耗过大，并且无法满足下行数据时延要求。
发明内容
本申请提供一种下行数据早传方法及装置，用以解决传输小数据量的下行数据包时资源利用效率低下的问题。
第一方面，提供一种下行数据早传方法，该方法的执行主体可以是终端，该方法通过以下步骤实现：向网络设备发送随机接入前导码，从所述网络设备接收随机接入响应，响应于所述随机接入响应，向所述网络设备发送消息3，所述消息3携带第一指示，所述第一指示用于指示单个下行数据包，从所述网络设备接收消息4，所述消息4携带下行数据。这样，通过终端向网络设备发送指示，可以使得网络设备根据终端发送的指示，在随机接入过程中将单个下行数据发送给终端，而并不建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
在一个可能的设计中，第一指示还可以用于指示下行数据早传；或者，第一指示还可以用于指示终端的下行数据可一次传输完成；或者，第一指示还可以用于指示终端在接收 完下行数据后不发送上行响应消息或上行数据；或者，第一指示还可以用于指示终端在接收完下行数据后释放连接。通过指示来使得网络设备执行下行数据早传的过程，节省功耗和通信资源。
在一个可能的设计中，所述消息3为用于请求恢复RRC连接的第一RRC消息。
在一个可能的设计中，所述消息4为用于指示释放所述RRC连接的第二RRC消息。
在一个可能的设计中，该方法还可以包括完整性保护和加解密的实现方式。具体的，恢复上下文信息，所述上下文信息包括第一下一跳链计数NCC，所述第一NCC用于推演第一密钥，使用所述第一密钥对所述下行数据进行解密。
在一个可能的设计中，还使用所述第一NCC推演第二密钥，使用所述第二密钥对所述消息4进行完整性保护校验。本设计对消息4进行完整性保护的方法，可以是本申请独立的设计，也可以与上一个可能的设计对下行数据进行加密的方案组合形成方案。
在一个可能的设计中，还可以使用第一NCC推演第二密钥和第四密钥，使用所述第二密钥对所述消息4进行完整性保护校验，使用所述第四密钥对所述消息4进行解密。本设计对消息4进行完整性保护的方法，可以是本申请独立的设计，也可以与上一个可能的设计对下行数据进行加密的方案组合形成方案。
在一个可能的设计中，所述上下文信息还包括第三密钥，使用所述第三密钥对所述消息4进行完整性保护校验。本设计对消息4进行完整性保护的方法，可以是本申请独立的设计，也可以与上一个可能的设计使用第一密钥对下行数据进行解密的方案组合形成方案。
在一个可能的设计中，所述上下文信息还包括承载配置信息和安全配置信息。
在一个可能的设计中，所述消息4包括第二NCC，还可以通过以下方法实现加解密和完整性保护的方案：使用所述第二NCC推演第五密钥，使用所述第五密钥对所述下行数据进行解密。
在一个可能的设计中，还可以使用所述第二NCC推演第六密钥，使用所述第六密钥对所述消息4进行完整性保护校验；或者，还可以使用上下文信息包括的第三密钥对所述消息4进行完整性保护。本设计对消息4进行完整性保护的两种方法，可以均是本申请独立的设计，也可以与上一个可能的设计中使用第五密钥对下行数据进行解密的方案组合形成方案。
通过以上几种完保和加解密的方法，能够防止消息4被篡改，以及保证下行数据的安全。
在一个可能的设计中，还可以从所述网络设备接收第二指示，所述第二指示用于指示单个下行数据包。具体的，可以从所述网络设备接收寻呼消息，所述寻呼消息中携带所述第二指示，所述寻呼消息用于寻呼所述终端。
在一个可能的设计中，还可以从所述网络设备接收准许指示，所述准许指示用于指示所述网络设备准许下行数据早传。
第二方面，提供一种下行数据早传方法，该方法的执行主体可以是终端，该方法通过以下步骤实现：向网络设备发送随机接入前导码，从所述网络设备接收随机接入响应，响应于所述随机接入响应，向所述网络设备发送消息3，所述消息3携带第一指示，所述第一指示用于指示单个下行数据包，从所述网络设备接收消息4，所述消息4为RRC消息，所述RRC消息中包含所述终端的下行数据。这样，通过终端向网络设备发送指示，可以 使得网络设备根据终端发送的指示，在随机接入过程中将单个下行数据发送给终端，而并不建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
在一个可能的设计中，所述消息3为RRC数据早传请求消息，所述消息4为RRC数据早传完成消息；或者，所述消息3为RRC连接请求消息，所述消息4为RRC数据早传完成消息；或者，所述消息3为RRC连接请求消息，所述消息4为RRC连接释放消息。
第三方面，提供一种下行数据早传方法，该方法的执行主体可以是网络设备，这里记为第一网络设备，该方法通过以下步骤实现：第一网络设备从终端接收随机接入前导码，所述第一网络设备向所述终端发送随机接入响应，所述第一网络设备从所述终端接收消息3，所述消息3携带第一指示，所述第一指示用于指示所述单个下行数据包，所述第一网络设备向所述终端发送消息4，所述消息4携带下行数据。这样，网络设备可以根据终端发送的指示，在随机接入过程中将单个下行数据发送给终端，而并不建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
在一个可能的设计中，第一指示还可以用于指示下行数据早传；或者，第一指示还可以用于指示终端的下行数据可一次传输完成；或者，第一指示还可以用于指示终端在接收完下行数据后不发送上行响应消息或上行数据；或者，第一指示还可以用于指示终端在接收完下行数据后释放连接。通过指示来使得网络设备执行下行数据早传的过程，节省功耗和通信资源。
在一个可能的设计中，所述消息3为用于请求恢复RRC连接的第一RRC消息。
在一个可能的设计中，所述消息4为用于指示释放所述RRC连接的第二RRC消息。
在一个可能的设计中，该方法还可以包括完整性保护和加解密的实现方式。具体的，所述第一网络设备恢复所述终端的上下文信息，所述上下文信息包括第一下一跳链计数NCC，所述第一NCC用于推演第一密钥；所述第一网络设备使用所述第一密钥对所述下行数据进行加密。
在一个可能的设计中，所述上下文信息还包括第三密钥，所述第一网络设备使用所述第三密钥对所述消息4进行完整性保护；或者，所述第一网络设备使用所述第一NCC推演第二密钥，所述第一网络设备使用所述第二密钥对消息4进行完整性保护；或者，所述第一网络设备使用所述第一NCC推演第二密钥和第四密钥，使用所述第二密钥对所述消息4进行完整性保护，使用所述第四密钥对所述消息4进行加密。在本设计中，包括三种对消息4进行完整性保护的方法，该三种方法可以均是本申请独立的设计，也可以与上一个可能的设计中使用第一密钥对下行数据进行加密的方案组合形成方案。
在一个可能的设计中，所述消息4携带第二NCC，还可以通过以下方法实现加解密和完整性保护的方案：所述第一网络设备使用所述第二NCC推演第五密钥，使用所述第五密钥对所述下行数据进行加密。
在一个可能的设计中，所述第一网络设备使用所述第二NCC推演第六密钥，使用所述第六密钥对所述消息4进行完整性保护；或者，所述第一网络设备恢复所述终端的上下文信息，所述上下文信息包括第三密钥，使用所述第三密钥对所述消息4进行完整性保护。本设计对消息4进行完整性保护的两种方法，可以均是本申请独立的设计，也可以与上一个可能的设计中使用第五密钥对下行数据进行加密的方案组合形成方案。
通过以上几种完保和加解密的方法，能够防止消息4被篡改，以及保证下行数据的安全。
在一个可能的设计中，所述第一网络设备还可以向所述终端发送第二指示，所述第二指示用于指示单个下行数据包。具体地，第一网络设备可以向终端发送寻呼消息，所述寻呼消息携带第二指示。
在一个可能的设计中，所述第一网络设备从第二网络设备接收第三指示，所述第三指示用于指示单个下行数据包。具体地，第一网络设备从第二网络设备接收寻呼消息，寻呼消息中携带所述第三指示。
在一个可能的设计中，所述第一网络设备从第三网络设备接收第四指示，所述第四指示用于指示单个下行数据包。
在一个可能的设计中，所述第一网络设备从第三网络设备接收下行数据，所述下行数据携带第四指示，所述第四指示用于指示单个下行数据包。
第四方面，提供一种下行数据早传方法，该方法的执行主体可以是网络设备，这里记为第一网络设备，该方法通过以下步骤实现：第一网络设备从第二网络设备接收寻呼消息，所述寻呼消息中携带第一指示，所述第一指示用于指示单个下行数据包；所述第一网络设备从终端接收随机接入前导码；所述第一网络设备向所述终端发送随机接入响应；所述第一网络设备从所述终端接收消息3；所述第一网络设备向所述终端发送消息4，所述消息4为RRC消息，所述RRC消息中包含所述终端的下行数据。第一网络设备可以根据终端以及核心网设备发送的指示，在随机接入过程中将单个下行数据发送给终端，而并不建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
在一个可能的设计中，第一指示还可以用于指示下行数据早传；或者，第一指示还可以用于指示终端的下行数据可一次传输完成；或者，第一指示还可以用于指示终端在接收完下行数据后不发送上行响应消息或上行数据；或者，第一指示还可以用于指示终端在接收完下行数据后释放连接。通过指示来使得网络设备执行下行数据早传的过程，节省功耗和通信资源。
在一个可能的设计中，所述消息3用于请求恢复RRC连接，所述消息4用于指示所述终端释放RRC连接。
在一个可能的设计中，该方法还可以包括完整性保护和加解密的实现方式。具体的，所述第一网络设备恢复所述终端的上下文信息，所述上下文信息包括第一下一跳链计数NCC，所述第一NCC用于推演第一密钥；所述第一网络设备使用所述第一密钥对所述下行数据进行加密。
在一个可能的设计中，所述上下文信息还包括第三密钥，所述第一网络设备使用所述第三密钥对所述消息4进行完整性保护；或者，所述第一网络设备使用所述第一NCC推演第二密钥，所述第一网络设备使用所述第二密钥对消息4进行完整性保护；或者，所述第一网络设备使用所述第一NCC推演第二密钥和第四密钥，使用所述第二密钥对所述消息4进行完整性保护，使用所述第四密钥对所述消息4进行加密。在本设计中，包括三种对消息4进行完整性保护的方法，该三种方法可以均是本申请独立的设计，也可以与上一个可能的设计中使用第一密钥对下行数据进行加密的方案组合形成方案。
在一个可能的设计中，所述消息4携带第二NCC，还可以通过以下方法实现加解密和 完整性保护的方案：所述第一网络设备使用所述第二NCC推演第五密钥，使用所述第五密钥对所述下行数据进行加密。
在一个可能的设计中，所述第一网络设备使用所述第二NCC推演第六密钥，使用所述第六密钥对所述消息4进行完整性保护；或者，所述第一网络设备恢复所述终端的上下文信息，所述上下文信息包括第三密钥，使用所述第三密钥对所述消息4进行完整性保护。本设计对消息4进行完整性保护的两种方法，可以均是本申请独立的设计，也可以与上一个可能的设计中使用第五密钥对下行数据进行加密的方案组合形成方案。
通过以上几种完保和加解密的方法，能够防止消息4被篡改，以及保证下行数据的安全。
在一个可能的设计中，所述第一网络设备向所述终端发送第二指示，所述第二指示用于指示单个下行数据包。具体地，第一网络设备可以向终端发送寻呼消息，所述寻呼消息携带第二指示。
在一个可能的设计中，所述第一网络设备从所述终端接收第三指示，所述第三指示用于指示单个下行数据包。
在一个可能的设计中，所述第一网络设备从第三网络设备接收第四指示，所述第四指示用于指示单个下行数据包。
在一个可能的设计中，所述第一网络设备从第三网络设备接收下行数据，所述下行数据携带第四指示，所述第四指示用于指示单个下行数据包。
第五方面，提供一种下行数据早传方法，该方法的执行主体可以是网络设备，这里记为第一网络设备，该方法通过以下步骤实现：第一网络设备从终端接收随机接入前导码；所述第一网络设备向所述终端发送随机接入响应；所述第一网络设备从所述终端接收第一指示，所述第一指示用于指示单个下行数据包；所述第一网络设备向所述终端发送消息4，所述消息4为RRC消息，所述RRC消息中包含所述终端的下行数据。这样，网络设备可以根据终端发送的指示，在随机接入过程中将单个下行数据发送给终端，而并不建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
在一个可能的设计中，第一指示还可以用于指示下行数据早传；或者，第一指示还可以用于指示终端的下行数据可一次传输完成；或者，第一指示还可以用于指示终端在接收完下行数据后不发送上行响应消息或上行数据；或者，第一指示还可以用于指示终端在接收完下行数据后释放连接。通过指示来使得网络设备执行下行数据早传的过程，节省功耗和通信资源。
在一个可能的设计中，所述消息3为RRC数据早传请求消息，所述消息4为RRC数据早传完成消息；或者，所述消息3为RRC连接请求消息，所述消息4为RRC数据早传完成消息；或者，所述消息3为RRC连接请求消息，所述消息4为RRC连接释放消息。
在一个可能的设计中，所述第一网络设备向所述终端发送第二指示，所述第二指示用于指示单个下行数据包。
在一个可能的设计中，所述第一网络设备从第二网络设备接收第三指示，所述第三指示用于指示单个下行数据包。
在一个可能的设计中，所述第三指示携带于寻呼消息中，或者，所述第三指示携带于NAS消息中。
在一个可能的设计中，所述第一网络设备从第二网络设备接收所述下行数据。可选的，所述下行数据携带于NAS消息中。
第六方面，提供一种下行数据早传方法，该方法的执行主体可以是核心网设备，这里记为第一核心网设备，该方法通过以下步骤实现：第一核心网设备从接入网设备接收终端初始化消息，所述终端初始化消息中携带第一指示，其中，所述第一指示用于指示单个下行数据包；所述第一核心网设备从第二核心网设备接收所述终端的下行数据；所述第一核心网设备向所述接入网设备发送NAS消息，所述NAS消息中携带所述终端的下行数据。这样，第一核心网设备可以根据终端发送的指示，将终端的下行数据封装于NAS消息中经由接入网设备发送给终端，不需要建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
在一个可能的设计中，所述第一核心网设备从第二核心网设备接收第二指示，所述第二指示用于指示单个下行数据包。可选的，所述第一核心网设备从第二核心网设备接收下行数据通知消息，所述下行数据通知消息中携带所述第一指示。
在一个可能的设计中，所述终端的下行数据中携带第二指示，所述第二指示用于指示单个下行数据包。
第六方面，提供一种下行数据早传方法，该方法的执行主体可以是核心网设备，这里记为第一核心网设备，该方法通过以下步骤实现：第一核心网设备从第二核心网设备接收第一指示，其中，所述第一指示用于指示单个下行数据包；所述第一核心网设备从所述第二核心网设备接收所述终端的下行数据；所述第一核心网设备向接入网设备发送NAS消息，所述NAS消息中携带所述终端的下行数据。第一核心网设备还可以从其他核心网设备接收指示，根据指示将终端的下行数据封装于NAS消息中经由接入网设备发送给终端，不需要建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
在一个可能的设计中，所述第一核心网设备从第二核心网设备接收下行数据通知消息，所述下行数据通知消息中携带所述第一指示。
在一个可能的设计中，所述第一核心网设备向所述接入网设备发送第二指示，所述第二指示用于指示单个下行数据包。可选的，所述第一核心网设备向所述接入网设备发送寻呼消息，所述寻呼消息中携带所述第二指示。
在一个可能的设计中，所述第一核心网设备从第二核心网设备接收所述终端的下行数据，所述终端的下行数据中携带所述第一指示。
在一个可能的设计中，所述NAS消息中还携带第二指示，所述第二指示用于指示单个下行数据包。
第八方面，提供一种下行数据早传装置，具有实现上述第一方面、第二方面、第一方面中任一种可能的设计或第二方面中任一种可能的设计中终端设备行为的功能，其包括用于执行上述方法方面所描述的步骤或功能相对应的部件(means)。所述步骤或功能可以通过软件实现，或硬件(如电路)实现，或者通过硬件和软件结合来实现。
在一种可能的设计中，上述装置包括一个或多个处理器和通信单元。所述一个或多个处理器被配置为支持所述下行数据早传装置执行上述方法中终端相应的功能。例如，向网络设备发送随机接入前导码，从网络设备接收随机接入响应，向网络设备发送消息3，在消息3中携带第一指示，从网络设备接收消息4。所述通信单元用于支持所述下行数据早 传装置与其他设备通信，实现接收和/或发送功能。例如，发送各个消息，接收各个消息。
可选的，所述装置还可以包括一个或多个存储器，所述存储器用于与处理器耦合，其保存装置必要的程序指令和/或数据。所述一个或多个存储器可以和处理器集成在一起，也可以与处理器分离设置。本申请并不限定。
所述通信单元可以是收发器，或收发电路。可选的，所述收发器也可以为输入/输出电路或者接口。
所述装置还可以为通信芯片。所述通信单元可以为通信芯片的输入/输出电路或者接口。
另一个可能的设计中，上述下行数据早传装置，包括收发器、处理器和存储器。该处理器用于控制收发器或输入/输出电路收发信号，该存储器用于存储计算机程序，该处理器用于运行该存储器中的计算机程序，使得该装置执行第一方面、第二方面、第一方面中任一种可能的设计或第二方面中任一种可能的设计中终端完成的方法。
第九方面，提供一种下行数据早传装置，具有实现上述第三方面、第四方面、第五方面、第三方面中任一种可能的设计、第四方面中任一种可能的设计或第五方面中任一种可能的设计中网络设备行为的功能，其包括用于执行上述方法方面所描述的步骤或功能相对应的部件(means)。所述步骤或功能可以通过软件实现，或硬件(如电路)实现，或者通过硬件和软件结合来实现。
在一种可能的设计中，上述下行数据早传装置包括一个或多个处理器和通信单元。所述一个或多个处理器被配置为支持所述下行数据早传装置执行上述第三方面、第四方面、第五方面、第三方面中任一种可能的设计、第四方面中任一种可能的设计或第五方面中任一种可能的设计中网络设备相应的功能。例如，从终端或其他网络设备接收指示，根据指示向终端发送下行数据。所述通信单元用于支持所述下行数据早传装置与其他设备通信，实现接收和/或发送功能。例如，接收指示，发送下行数据。
可选的，所述装置还可以包括一个或多个存储器，所述存储器用于与处理器耦合，其保存网络设备必要的程序指令和/或数据。所述一个或多个存储器可以和处理器集成在一起，也可以与处理器分离设置。本申请并不限定。
所述下行数据早传装置可以为基站，gNB或TRP等，所述通信单元可以是收发器，或收发电路。可选的，所述收发器也可以为输入/输出电路或者接口。
所述装置还可以为通信芯片。所述通信单元可以为通信芯片的输入/输出电路或者接口。
另一个可能的设计中，上述下行数据早传装置，包括收发器、处理器和存储器。该处理器用于控制收发器或输入/输出电路收发信号，该存储器用于存储计算机程序，该处理器用于运行存储器中的计算机程序，使得该装置执行上述第三方面、第四方面、第五方面、第三方面中任一种可能的设计、第四方面中任一种可能的设计或第五方面中任一种可能的设计中网络设备完成的方法。
第十方面，提供一种下行数据早传装置，具有实现上述第六方面、第七方面、第六方面中任一种可能的设计或第七方面中任一种可能的设计中核心网设备行为的功能，其包括用于执行上述方法方面所描述的步骤或功能相对应的部件(means)。所述步骤或功能可以通过软件实现，或硬件(如电路)实现，或者通过硬件和软件结合来实现。
在一种可能的设计中，上述下行数据早传装置包括一个或多个处理器和通信单元。所 述一个或多个处理器被配置为支持所述下行数据早传装置执行上述第六方面、第七方面、第六方面中任一种可能的设计或第七方面中任一种可能的设计中网络设备相应的功能。例如，从接入网设备接收指示，从其他核心网设备接收下行数据，将下行数据携带与NAS消息中下发给接入网设备。所述通信单元用于支持所述下行数据早传装置与其他设备通信，实现接收和/或发送功能。例如，接收指示，发送下行数据。
可选的，所述下行数据早传装置还可以包括一个或多个存储器，所述存储器用于与处理器耦合，其保存网络设备必要的程序指令和/或数据。所述一个或多个存储器可以和处理器集成在一起，也可以与处理器分离设置。本申请并不限定。
所述下行数据早传装置可以为MME等，所述通信单元可以是收发器，或收发电路。可选的，所述收发器也可以为输入/输出电路或者接口。
所述装置还可以为通信芯片。所述通信单元可以为通信芯片的输入/输出电路或者接口。
另一个可能的设计中，上述下行数据早传装置，包括收发器、处理器和存储器。该处理器用于控制收发器或输入/输出电路收发信号，该存储器用于存储计算机程序，该处理器用于运行存储器中的计算机程序，使得该装置执行上述第六方面、第七方面、第六方面中任一种可能的设计或第七方面中任一种可能的设计中核心网设备完成的方法。
第十一方面，提供了一种系统，该系统包括上述第八方面、第九方面或第十方面中的至少两个方面提供的下行数据早传装置。
第十二方面，提供了一种计算机可读存储介质，用于存储计算机程序，该计算机程序包括用于执行第一方面、第二方面、第一方面中任一种可能的设计或第二方面中任一种可能的设计中的方法的指令。
第十三方面，提供了一种计算机可读存储介质，用于存储计算机程序，该计算机程序包括用于执行第三方面、第四方面、第五方面、第三方面中任一种可能的设计、第四方面中任一种可能的设计或第五方面中任一种可能的设计中的方法的指令。
第十四方面，提供了一种计算机可读存储介质，用于存储计算机程序，该计算机程序包括用于执行第六方面、第七方面、第六方面中任一种可能的设计或第七方面中任一种可能的设计中的方法的指令。
第十五方面，提供了一种计算机程序产品，所述计算机程序产品包括：计算机程序代码，当所述计算机程序代码在计算机上运行时，使得计算机执行上述第一方面、第二方面、第一方面中任一种可能的设计或第二方面中任一种可能的设计中的方法。
第十六方面，提供了一种计算机程序产品，所述计算机程序产品包括：计算机程序代码，当所述计算机程序代码在计算机上运行时，使得计算机执行上述第三方面、第四方面、第五方面、第三方面中任一种可能的设计、第四方面中任一种可能的设计或第五方面中任一种可能的设计中的方法。
第十七方面，提供了一种计算机程序产品，所述计算机程序产品包括：计算机程序代码，当所述计算机程序代码在计算机上运行时，使得计算机执行上述第六方面、第七方面、第六方面中任一种可能的设计或第七方面中任一种可能的设计中的方法。
附图说明
图1为本申请实施例中通信系统架构示意图；
图2a为本申请实施例中下行数据早传方法之一的流程示意图；
图2b为本申请实施例中下行数据早传方法之二的流程示意图；
图2c为本申请实施例中下行数据早传方法之三的流程示意图；
图3a为本申请实施例中下行数据早传方法之四的流程示意图；
图3b为本申请实施例中下行数据早传方法之五的流程示意图；
图3c为本申请实施例中下行数据早传方法之六的流程示意图；
图3d为本申请实施例中下行数据早传方法之七的流程示意图；
图4a为本申请实施例中下行数据早传方法的实现方式之一的流程示意图；
图4b为本申请实施例中下行数据早传方法的实现方式之二的流程示意图；
图4c为本申请实施例中下行数据早传方法的实现方式之三的流程示意图；
图5a为本申请实施例中下行数据早传方法的实现方式之四的流程示意图；
图5b为本申请实施例中下行数据早传方法的实现方式之五的流程示意图；
图5c为本申请实施例中下行数据早传方法的实现方式之六的流程示意图；
图6a为本申请实施例中下行数据早传方法的实现方式之七的流程示意图；
图6b为本申请实施例中下行数据早传方法的实现方式之八的流程示意图；
图6c为本申请实施例中下行数据早传方法的实现方式之九的流程示意图；
图7a为本申请实施例中下行数据早传方法的实现方式之十的流程示意图；
图7b为本申请实施例中下行数据早传方法的实现方式之十一的流程示意图；
图7c为本申请实施例中下行数据早传方法的实现方式之十二的流程示意图；
图8a为本申请实施例中下行数据早传方法的实现方式之十三的流程示意图；
图8b为本申请实施例中下行数据早传方法的实现方式之十四的流程示意图；
图8c为本申请实施例中下行数据早传方法的实现方式之十五的流程示意图；
图9a为本申请实施例中下行数据早传方法的实现方式之十六的流程示意图；
图9b为本申请实施例中下行数据早传方法的实现方式之十七的流程示意图；
图9c为本申请实施例中下行数据早传方法的实现方式之十八的流程示意图；
图10a为本申请实施例中下行数据早传方法的实现方式之十九的流程示意图；
图10b为本申请实施例中下行数据早传方法的实现方式之二十的流程示意图；
图10c为本申请实施例中下行数据早传方法的实现方式之二十一的流程示意图；
图11为本申请实施例中下行数据早传装置结构示意图之一；
图12为本申请实施例中下行数据早传装置结构示意图之二；
图13为本申请实施例中下行数据早传装置结构示意图之三。
具体实施方式
下面将结合附图，对本申请实施例进行详细描述。
本申请实施例提供一种下行数据早传方法及装置，通过使用简单的连接建立过程，实现下行数据的提前传输，以提高资源利用效率，降低终端的功耗。其中，方法和装置是基于同一发明构思的，由于方法及装置解决问题的原理相似，因此装置与方法的实施可以相互参见，重复之处不再赘述。本申请实施例的描述中，“和/或”，描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和 B，单独存在B这三种情况。字符“/”一般表示前后关联对象是一种“或”的关系。本申请中所涉及的至少一个是指一个或多个；多个，是指两个或两个以上。另外，需要理解的是，在本申请的描述中，“第一”、“第二”等词汇，仅用于区分描述的目的，而不能理解为指示或暗示相对重要性，也不能理解为指示或暗示顺序。
本申请实施例提供的通信方法可以应用于第四代(4th generation，4G)通信系统、第五代(5th generation，5G)通信系统或未来的各种通信系统。具体的，可以应用于MTC的通信场景，也可以应用于NB-IoT的通信场景，也可以应用于任意下行小数据包的传输场景。
下面将结合附图，对本申请实施例进行详细描述。
图1示出了本申请实施例提供的下行数据早传方法适用的一种可能的通信系统的架构，参阅图1所示，通信系统100中包括一个或多个接入网设备、一个或多个终端以及一个或多个核心网设备，每个接入网设备可以为覆盖范围内的一个或多个终端提供服务，接入网设备之间通过X2接口相连以进行通信，接入网设备与核心网设备之间通过S1接口相连。例如，如图1中所述，通信系统100中包括接入网设备101和接入网设备101’，接入网设备101的覆盖范围内的终端用终端102来表示，接入网设备101’的覆盖范围内的终端用终端102’来表示。通信系统100中还包括核心网设备103和核心网设备103’。以下对通信系统中包括的接入网设备、终端和核心网设备的形态进行举例说明。以接入网设备101、终端102和核心网设备103进行说明。
接入网设备101为无线接入网(radio access network，RAN)中的节点，又可以称为基站，还可以称为RAN节点(或设备)。目前，一些接入网设备101的举例为：gNB/NR-NB、传输接收点(transmission reception point，TRP)、演进型节点B(evolved Node B，eNB)、无线网络控制器(radio network controller，RNC)、节点B(Node B，NB)、基站控制器(base station controller，BSC)、基站收发台(base transceiver station,BTS)、家庭基站(例如，home evolved NodeB，或home Node B，HNB)、基带单元(base band unit，BBU)，或无线保真(wireless fidelity，Wifi)接入点(access point，AP)，或5G通信系统或者未来可能的通信系统中的网络侧设备等。
终端102，又称之为用户设备(user equipment，UE)、移动台(mobile station，MS)、移动终端(mobile terminal，MT)等，是一种向用户提供语音或数据连通性的设备，也可以是物联网设备。例如，终端102包括具有无线连接功能的手持式设备、车载设备等。目前，终端102可以是：手机(mobile phone)、平板电脑、笔记本电脑、掌上电脑、移动互联网设备(mobile internet device，MID)、可穿戴设备(例如智能手表、智能手环、计步器等)，车载设备(例如，汽车、自行车、电动车、飞机、船舶、火车、高铁等)、虚拟现实(virtual reality，VR)设备、增强现实(augmented reality，AR)设备、工业控制(industrial control)中的无线终端、智能家居设备(例如，冰箱、电视、空调、电表等)、智能机器人、车间设备、无人驾驶(self driving)中的无线终端、远程手术(remote medical surgery)中的无线终端、智能电网(smart grid)中的无线终端、运输安全(transportation safety)中的无线终端、智慧城市(smart city)中的无线终端，或智慧家庭(smart home)中的无线终端、飞行设备(例如，智能机器人、热气球、无人机、飞机)等。
核心网设备102，用于网络设备101与IP网络之间的通信，IP网络可以是因特网(internet)，私有的IP网，或其它数据网等。以长期演进(long term evolution，LTE)通 信系统为例，核心网设备102包括移动管理实体(mobile management entity，MME)/服务网关(service-network gateway，S-GW)。
本申请实施例涉及的终端可能具有业务单一的特点，例如终端的下行数据每次传输仅有一个下行数据包。对于一个下行数据包的场景，本申请实施例可以但不限于以下应用场景：
场景1、终端的下行数据量小于设定阈值；
场景2、核心网设备可以将终端的下行数据通过一个网络协议IP包发送给接入网设备；
场景3、接入网设备可以将终端的下行数据通过一个传输块(transmission block,TB)发送给终端；
场景4、核心网设备将终端的下行数据通过多次发送给接入网设备，但是接入网设备可以将多次接收的下行数据通过一个TB发送给终端。
本申请实施例中，核心网设备和接入网设备均可以称为网络设备。在本申请的描述中，为方便说明，本申请实施例可以用“第一”、“第二”等词汇来区分描述，可以理解的是，该类词汇不能理解为指示或暗示相对重要性，也不能理解为指示或暗示顺序。
本申请实施例的核心思想是，网络设备接收指示(indication)，根据指示确定终端的下行数据仅有一个下行数据包，则通过一条消息将终端的下行数据下发给终端，能够节省信令的消耗，避免资源的浪费。
以下为本文中对指示(indication)的解释。
本申请实施例中，根据发送指示的设备以及接收指示的设备不同，为作区分描述，以“第一指示”、“第二指示”、“第三指示”等来表示，可以理解的是，涉及到的不同命名方式的指示所指示的意义是相同或类似的。以下就本申请实施例涉及的“指示(indication)”所指示的含义做举例说明，指示的含义可以是以下举例中的任意一种或多种。
例1、指示下行数据早传；
例2、指示终端的下行数据可一次传输完成，即终端的下行数据可以通过一条消息传输完，例如通过消息4传输，下行数据和消息4中的RRC消息可以在一个TB中发送，或者，下行数据和消息4可以在一个TB中发送；
本申请实施例中，消息4为随机接入过程中终端与网络设备之间交互的第4条消息。
例3、指示终端在接收完下行数据后不发送上行响应消息或上行数据；
例4、指示终端在接收完下行数据后释放连接。
例5、指示单个下行数据包，即指示核心网设备可以通过一个IP包发送终端的下行数据，表示为单个下行数据包(single packet)，或者单个下行数据(single DL data)；
例6、指示单个下行数据包，即指示接入网设备可以通过一个TB发送终端的下行数据，表示为单个下行数据包(single packet)，或者单个下行数据(single DL data)。
例7、指示小包传输，可以理解为终端的下行数据量小于一个阈值。
以下描述中，交互的设备可以用终端、第一网络设备、第二网络设备和第三网络设备来表示，其中，第一网络设备为接入网设备，例如，接入网设备可以是eNB。第二网络设备和第三网络设备为核心网设备，例如，第二网络设备记为第一核心网设备，第三网络设备记为第二核心网设备，第二网络设备可以是MME，第三网络设备可以是S-GW。
基于上述描述，在一种可能的实现方式中，如图2a所示，本申请实施例提供的下行数据早传方法之一的具体过程如下所述。
S201a、终端向第一网络设备发送消息1(Msg1)，第一网络设备从终端接收消息1(Msg1)，该消息1为随机接入前导码(random access preamble)。
具体的，第一网络设备通过广播消息广播若干个随机接入前导码，当该终端需要发起随机接入过程时，从接收到的若干个随机接入前导码中随机选择一个，并将所选择的随机接入前导码发送给第一网络设备。
在S201a之前，终端接收第一网络设备发送的寻呼(Paging)消息。
S202a、第一网络设备向终端发送消息2(Msg2)，终端从第一网络设备接收消息2。
其中，该消息2为随机接入响应(random access response)。
S203a、终端向第一网络设备发送消息3(Msg3)，第一网络设备从终端接收消息3(Msg3)。
其中，消息3中携带一个指示，该指示所指示的含义可以参考上文中的描述。
该消息3可以是一条RRC消息，这里记为第一RRC消息。例如，该第一RRC消息为RRC连接恢复请求(RRC connection resum request)消息，用于请求恢复RRC连接。
可选的，第一RRC消息中还可携带恢复标识(resume ID)、恢复原因(resume cause)、截短的恢复MAC-I(short resume MAC-I)，MAC-I为用于完整性保护的消息鉴权码(message authentication code for integrity)。其中，resume ID用于标识被挂起的终端；resume cause用于指示该终端恢复连接的原因，例如，resume cause的值为被叫接入(mobile terminating-Access，mt-Access)，或者，resume cause的值为新增加的值，该新增加的值用于指示恢复连接的原因为传输单个下行数据；short resume MAC-I用于对Msg3进行完整性保护，以防止Msg3被篡改。
在本申请中，消息A携带B可以有多种方法。作为一种可选的方法，可以利用消息A所包括的信元或者域来携带B，即可以理解为消息A包括B。作为另一种可选的方法，可以将B和消息A封装在一起来实现消息A携带B，例如将B和消息A封装在一个MAC PDU中，又例如将B和消息A封装在一个传输块中等。举例来说，上述消息A携带B在本申请中可以是消息3携带指示(即文中的第一指示)，也可以是消息4携带下行数据等。
可选的，第三网络向终端发送下行数据，终端从第三网络设备接收下行数据。在下行数据中携带指示，指示的含义如上文中所述。例如，可以在下行数据包的用户面GPRS隧道协议(GPRS tunneling protocol-user plane，GTP-U)报文的报头携带该指示，其中，GPRS为通用分组无线服务技术(general packet radio service)。
S204a、第一网络设备向终端发送消息4(Msg4)，终端从第一网络设备接收消息4。
其中，消息4携带下行数据，该下行数据为第三网络设备向第一网络设备下发的下行数据。第一网络设备收到S203a的指示后，可以根据该指示，利用消息4将下行数据发送至终端。消息4可以是一条RRC消息，记为第二RRC消息，例如，第二RRC消息为RRC连接释放(RRC connection release)消息。其中消息4携带下行数据可以理解为将消息4和下行数据封装在一条消息中。或者，消息4包含第二RRC消息和下行数据。例如：Msg4承载在公共控制信道(common control channel，CCCH)的逻辑信道上(即承载在SRB0上)，下行数据承载在专用业务信道(dedicated traffic channel，DTCH)信道上(即承载在DRB上)，这两个信道上的数据即MAC业务数据单元(medium access control service data units，MAC SDU)在媒体接入控制(medium access control，MAC)层进行复用，形成媒体接入控制协议数据单元(medium access control packet data unit，MAC PDU)，第一网络 设备向终端发送MAC PDU，终端接收第一网络设备发送的MAC PDU。
可选的，消息4中可携带恢复标识(resume ID)、释放原因(release cause)、下一跳链计数(next hop chaining count，NCC)。
其中，resume ID用于标识被挂起的终端，release cause用于指示该释放该终端上下文的原因，例如，release cause的值可以是RRC挂起(即rrc-suspend)。
通过上述下行数据早传方法之一，第一网络设备可以根据终端发送的指示，在随机接入过程中将单个下行数据发送给终端，而并不建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
在一种可能的实现方式中，还可以通过核心网设备向接入网设备发送指示。具体的，如图2b所示，本申请实施例提供的下行数据早传方法之二的具体过程如下所述。
S201b、第三网络设备向第二网络设备发送下行数据通知消息，第二网络设备从第三网络设备接收下行数据通知消息。
该下行数据通知消息中携带指示，该指示的含义可以参考上文中的描述。该下行数据通知消息中还可携带终端的标识，例如，S-TMSI和/或Resume ID。
S202b、第二网络设备向第一网络设备发送寻呼消息，第一网络设备从第二网络设备接收寻呼消息。
该寻呼消息中携带指示，同样，该指示的含义可以参考上文中的描述。该寻呼消息中还可携带终端的标识，例如，S-TMSI和/或Resume ID。
可选的，在S202b之前，第一网络设备向第二网络设备发送该终端的Resume ID。
S203b、第一网络设备向终端发送寻呼消息，终端接收第一网络设备发送的寻呼消息。
可选的，在本步骤发送的寻呼消息中也可以携带指示，该指示的含义可以参考上文中的描述。
S204b、同S201a。
S205b、同S202a。
S206b、终端向第一网络设备发送消息3(Msg3)，第一网络设备从终端接收消息3(Msg3)。
该消息3为第一RRC消息，第一RRC消息可以用于请求恢复RRC连接，例如，该第一RRC消息为RRC连接恢复请求(RRC connection resum request)消息。
可选的，第一RRC消息中还可携带恢复标识(resume ID)、恢复原因(resume cause)、short resume MAC-I。
第一网络设备接收到第一RRC消息，根据resume ID或者根据resume ID与S-TMSI之间的映射关系，确定被挂起的该终端即为核心网发送的指示所指示的终端，进一步确定该终端的下行数据可一次传输完成，于是在后续S207b中在消息4携带终端的下行数据。
第三网络设备向第一网络设备发送下行数据，第一网络设备从第三网络设备接收下行数据。在下行数据中携带指示，指示的含义如上文中所述。例如，可以在下行数据包的GTP-U协议报文的报头携带该指示。
S207b、同S204a。
通过上述下行数据早传方法之二，第一网络设备可以根据核心网设备发送的指示，在随机接入过程中将单个下行数据发送给终端，而并不建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功 耗。
在另一种可能的实现方式中，可以通过核心网设备和终端两侧来向接入网设备发送指示。具体的，如图2c所示，本申请实施例提供的下行数据早传方法之三的具体过程如下所述。
S201c、第三网络设备向第二网络设备发送下行数据通知消息，第二网络设备从第三网络设备接收下行数据通知消息。
该下行数据通知消息中携带指示，该指示的含义可以参考上文中的描述。该下行数据通知消息中还可携带终端的标识，例如，S-TMSI。
S202c、第二网络设备向第一网络设备发送寻呼消息，第一网络设备从第二网络设备接收寻呼消息。
该寻呼消息中携带指示，同样，该指示的含义可以参考上文中的描述。该寻呼消息中还可携带终端的标识，例如，S-TMSI。
S203c、第一网络设备向终端发送寻呼消息，终端接收第一网络设备发送的寻呼消息。
可选的，在本步骤发送的寻呼消息中也可以携带指示，该指示的含义可以参考上文中的描述。
S204c、终端向第一网络设备发送消息1(Msg1)，第一网络设备从终端接收消息1(Msg1)，该消息1为随机接入前导码(random access preamble)。
S205c、第一网络设备向终端发送消息2(Msg2)，终端从第一网络设备接收消息2。
其中，该消息2为随机接入响应(random access response)。
S206c、终端向第一网络设备发送消息3(Msg3)，第一网络设备从终端接收消息3(Msg3)。
其中，消息3中携带一个指示，该指示所指示的含义可以参考上文中的描述。
例如，该消息3可以是RRC连接恢复请求(RRC connection resum request)消息，用于请求恢复RRC连接。
可选的，第一RRC消息中还可携带恢复标识(resume ID)、恢复原因(resume cause)、short resume MAC-I。
第一网络设备接收到第一RRC消息，根据指示，确定该终端的下行数据可一次传输完成。于是在后续S207c中在消息4携带终端的下行数据。
可选的，第三网络向终端发送下行数据，终端从第三网络设备接收的下行数据。在下行数据中携带指示，指示的含义如上文中所述。例如，可以在下行数据包的GTP-U协议报文的报头携带该指示。
S207c、第一网络设备向终端发送消息4(Msg4)，终端从第一网络设备接收消息4。
其中，消息4携带下行数据，该下行数据为第三网络设备向第一网络设备下发的下行数据。消息4可以是一条RRC消息，例如，RRC连接释放(RRC connection release)消息。
本步骤的其余描述同S204a。
通过上述下行数据早传方法之三，第一网络设备可以根据终端以及核心网设备发送的指示，在随机接入过程中将单个下行数据发送给终端，而并不建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
以下结合上述下行数据早传方法之一、下行数据早传方法之二和下行数据早传方法之 三，示例性的介绍几种在下行数据早传过程中的完整性保护和加解密的方法，所举例的方法1～方法5适用于上述三种下行数据早传方法中。
方法1、第一网络设备在向终端发送消息4(Msg4)之前，恢复该终端的上下文信息，该终端的上下文信息中包含NCC，这里记为第一NCC，第一网络设备使用第一NCC推演新的密钥，记为第一密钥，用K 1 RRCenc表示。该终端的上下文信息中还包含旧密钥，记为第三密钥，用K 3 RRCint表示。第一网络设备使用第三密钥对第二RRC消息进行完整性保护，并使用第一密钥对下行数据进行加密。将执行完整性保护的第二RRC消息和加密的下行数据携带于消息4中发送给终端。
对于终端侧，终端在接收到第一网络设备发送消息4(Msg4)之后，恢复该终端的上下文信息，同样的，该终端的上下文信息中包含第一NCC和第三密钥。终端使用第一NCC推演第一密钥，使用第三密钥对接收到的第二RRC消息进行完整性保护校验，并使用第一密钥对接收到的下行数据进行解密。
方法2、第一网络设备在向终端发送消息4(Msg4)之前，恢复该终端的上下文信息，该终端的上下文信息中包含第一NCC，第一网络设备使用第一NCC推演第一密钥和第二密钥，第一密钥用K 1 RRCenc表示，第二密钥用K 2 RRCint表示。第一网络设备使用第二密钥对第二RRC消息进行完整性保护，使用第一密钥对下行数据进行加密。将执行完整性保护的第二RRC消息和加密的下行数据携带于消息4中发送给终端。
对于终端侧，终端在接收到第一网络设备发送消息4(Msg4)之后，恢复该终端的上下文信息，同样的，该终端的上下文信息中包含第一NCC。终端使用第一NCC推演第一密钥和第二密钥，使用第二密钥对接收到的第二RRC消息进行完整性保护校验，使用第一密钥对接收到的下行数据进行解密。
方法3、第一网络设备在向终端发送消息4(Msg4)之前，恢复该终端的上下文信息，该终端的上下文信息中包含第一NCC，第一网络设备使用第一NCC推演第一密钥、第二密钥和第四密钥。第二密钥用K 2 RRCint表示，第四密钥用K 4 RRCenc表示。第一网络设备使用第二密钥对第二RRC消息进行完整性保护，使用第四密钥对第二RRC消息进行加密，使用第一密钥对下行数据进行加密。将执行完整性保护和加密的第二RRC消息和加密的下行数据携带于消息4中发送给终端。
对于终端侧，终端在向第一网络设备发送消息3(Msg3)之前，恢复该终端的上下文信息，该终端的上下文信息中包含第一NCC，终端使用第一NCC推演第一密钥、第二密钥和第四密钥。终端接收到消息4，使用第二密钥和第四密钥对第二RRC消息进行完整性保护校验和解密，以及使用第一密钥对接收到的下行数据进行解密。
方法4、第一网络设备在向终端发送消息4(Msg4)之前，恢复该终端的上下文信息，该终端的上下文信息中包含旧密钥，记为第三密钥。第一网络设备在向终端发送的消息4(Msg4)中携带第二NCC，并使用该第二NCC推演的第五密钥，第五密钥用K 5 RRCenc表示。第一网络设备使用第三密钥对第二RRC消息进行完整性保护，并使用推演出来的第五密钥对下行数据进行加密。将执行完整性保护的第二RRC消息和加密的下行数据携带于消息4中发送给终端。
对于终端侧，终端在向第一网络设备发送消息3(Msg3)之前，恢复该终端的上下文信息，该终端的上下文信息中包含旧密钥，记为第三密钥。终端接收到消息4，使用第三密钥对第二RRC消息进行完整性保护校验。消息4携带第二NCC，终端使用该第二NCC 推演第五密钥，使用第五密钥对下行数据进行解密。
方法5、第一网络设备在向终端发送消息4(Msg4)之前，恢复该终端的上下文信息，第一网络设备在向终端发送的消息4(Msg4)中携带第二NCC，第一网络设备使用该第二NCC推演第五密钥和第六密钥，第六密钥用K 6 RRCint表示。第一网络设备使用推演出来的第六密钥对第二RRC消息进行完整性保护，使用推演出来的第五密钥对下行数据进行加密。将执行完整性保护的第二RRC消息和加密的下行数据携带于消息4中发送给终端。
对于终端侧，终端在向第一网络设备发送消息3(Msg3)之前，恢复该终端的上下文信息。终端接收到消息4，消息4携带第二NCC，终端使用该第二NCC推演第五密钥和第六密钥，使用第六密钥对第二RRC消息进行完整性保护校验，使用第五密钥对下行数据进行解密。
如图3a所示，本申请实施例提供的下行数据早传方法之四的具体过程如下所述。
S301a、终端向第一网络设备发送消息1(Msg1)，第一网络设备从终端接收消息1(Msg1)，该消息1为随机接入前导码(random access preamble)。
在S301a之前，终端接收第一网络设备发送的寻呼消息(Paging)。
S302a、第一网络设备向终端发送消息2(Msg2)，终端从第一网络设备接收消息2。
其中，该消息2为随机接入响应(random access response)。
S303a、终端向第一网络设备发送第一RRC消息，第一网络设备从终端接收第一RRC消息。
其中，第一RRC消息中携带一个指示，记为第一指示，该第一指示所指示的含义可以参考上文中的描述。
S304a、第一网络设备向第二网络设备发送第二指示，第二网络设备从第一网络设备接收第二指示。
该第二指示所指示的含义可以参考上文中的描述。
例如，第二指示可以携带于终端初始化消息(Initial UE Message)中。则本步骤中，第一网络设备向第二网络设备发送终端初始化消息，第二网络设备从第一网络设备接收终端初始化消息，该终端初始化消息中携带第二指示。
S305a、第三网络设备向第二网络设备发送下行数据，第二网络设备接收第三网络设备发送的下行数据。
S306a、第二网络设备将下行数据封装在NAS消息中，第二网络设备通过下行NAS传输(downlink NAS transport)将下行数据发送给第一网络设备，第一网络设备接收第二网络设备发送的下行NAS消息。
S307a、第一网络设备向终端发送第二RRC消息，终端从第一网络设备接收第二RRC消息。
其中，第二RRC消息中携带下行数据。
具体的，第一网络设备根据S303a中的指示确定终端的下行数据可一次传输完成，则第一网络设备将接收到的包含终端下行数据的下行NAS消息封装在第二RRC消息中，将第二RRC消息发送给终端。
示例性的，以下对下行数据早传方法之四中上述描述的第一RRC消息和第二RRC消息的可能的功能或含义给予说明。
第一RRC消息为RRC数据早传请求(RRC early data request)消息，用于请求上行数 据早传，该RRC数据早传请求消息中携带第一指示，该第一指示指示的含义可以是single packet，或者single DL data，也可以通过dedicated Info NAS来指示，其中dedicated Info NAS本来的功能是用于承载早传的上行数据，在下行数据早传场景中，假设终端没有上行数据，此时RRC数据早传请求消息是用于通知下行数据早传的，所以可以将dedicated Info NAS置为空NULL，用于指示未携带上行数据，进一步指示为下行数据早传。第二RRC消息为RRC数据早传完成(RRC early data complete)消息，用于携带早传的下行数据。
或者，第一RRC消息为RRC连接请求(RRC Connection Request)消息。用于请求建立RRC连接，该RRC连接请求消息中携带第一指示，该第一指示的功能和所指示的含义可以参考上文中的描述。第二RRC消息为RRC数据早传完成消息，用于携带早传的下行数据。
或者，第一RRC消息为RRC连接请求消息，用于请求建立RRC连接，该RRC连接请求消息中携带第一指示，该第一指示的功能和所指示的含义可以参考上文中的描述。第二RRC消息为RRC连接释放消息，用于通知释放RRC连接，以及用于携带早传的下行数据。
通过上述下行数据早传方法之四，第二网络设备可以根据终端发送的指示，将终端的下行数据封装于NAS消息中经由第一网络设备发送给终端，不需要建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
在一种可能的实现方式中，还可以通过第三网络设备向第二网络设备发送指示。具体的，如图3b所示，本申请实施例提供的下行数据早传方法之五的具体过程如下所述。
S301b、第三网络设备向第二网络设备发送下行数据通知消息，第二网络设备从第三网络设备接收下行数据通知消息。
该下行数据通知消息中携带指示，该指示的含义可以参考上文中的描述。该下行数据通知消息中还可携带终端的标识，例如，S-TMSI。
S302b、第二网络设备向第一网络设备发送寻呼消息，第一网络设备从第二网络设备接收寻呼消息。
该寻呼消息中携带指示，同样，该指示的含义可以参考上文中的描述。该寻呼消息中还可携带终端的标识，例如，S-TMSI。
S303b、第一网络设备向终端发送寻呼消息，终端接收第一网络设备发送的寻呼消息。
可选的，在本步骤发送的寻呼消息中也可以携带指示，该指示的含义可以参考上文中的描述。
S304b、终端向第一网络设备发送消息1(Msg1)，第一网络设备从终端接收消息1(Msg1)，该消息1为随机接入前导码(random access preamble)。
S305b、第一网络设备向终端发送消息2(Msg2)，终端从第一网络设备接收消息2。
其中，该消息2为随机接入响应(random access response)。
S306b、终端向第一网络设备发送第一RRC消息，第一网络设备从终端接收第一RRC消息。
S307b、第三网络设备向第二网络设备发送下行数据，第二网络设备接收第三网络设备发送的下行数据。
S308b、第二网络设备将下行数据封装在NAS消息中，第二网络设备通过下行NAS 传输将下行数据发送给第一网络设备，第一网络设备接收第二网络设备发送的下行NAS消息。
具体的，第二网络设备根据指示确定终端的下行数据可一次传输完成，则第二网络设备将下行数据封装在NAS消息中，发送给第一网络设备。
S309b、第一网络设备向终端发送第二RRC消息，终端从第一网络设备接收第二RRC消息。
其中，第二RRC消息中携带下行数据。
具体的，第一网络设备根据S302b或S306b中的指示确定终端的下行数据可一次传输完成，则第一网络设备将接收到的包含终端的下行数据的NAS消息封装在第二RRC消息中，将第二RRC消息发送给终端。
通过上述下行数据早传方法之五，第二网络设备可以根据第三网络设备发送的指示，将终端的下行数据封装于NAS消息中经由第一网络设备发送给终端，不需要建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
在另一种可能的实现方式中，通过第三网络设备向第二网络设备发送指示，还可以通过以下方式实现。如图3c所示，本申请实施例提供的下行数据早传方法之六的具体过程如下所述。
S301c、第三网络设备向第二网络设备发送下行数据通知消息，第二网络设备从第三网络设备接收下行数据通知消息。
该下行数据通知消息中携带指示，该指示的含义可以参考上文中的描述。该下行数据通知消息中还可携带终端的标识，例如，S-TMSI。
S302c、第二网络设备向第一网络设备发送寻呼消息，第一网络设备从第二网络设备接收寻呼消息。
该寻呼消息中还可携带终端的标识，例如，S-TMSI。
S303c、第一网络设备向终端发送寻呼消息，终端接收第一网络设备发送的寻呼消息。
S304c、终端向第一网络设备发送消息1(Msg1)，第一网络设备从终端接收消息1(Msg1)，该消息1为随机接入前导码(random access preamble)。
S305c、第一网络设备向终端发送消息2(Msg2)，终端从第一网络设备接收消息2。
其中，该消息2为随机接入响应(random access response)。
S306c、终端向第一网络设备发送第一RRC消息，第一网络设备从终端接收第一RRC消息。
S307c、第三网络设备向第二网络设备发送下行数据，第二网络设备接收第三网络设备发送的下行数据。
S308c、第二网络设备将下行数据封装在NAS消息中，第二网络设备通过下行NAS传输将下行数据发送给第一网络设备，第一网络设备接收第二网络设备发送的下行NAS消息。该NAS消息还携带指示，该指示的含义可以参考上文中的描述。
S309c、第一网络设备向终端发送第二RRC消息，终端从第一网络设备接收第二RRC消息。
其中，第二RRC消息中携带下行数据。
具体的，第一网络设备将接收到的NAS消息封装在第二RRC消息中，将第二RRC 消息发送给终端。
通过上述下行数据早传方法之六，第二网络设备可以根据第三网络设备发送的指示，将终端的下行数据封装于NAS消息中经由第一网络设备发送给终端，不需要建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
在另一种可能的实现方式中，通过第三网络设备向第二网络设备发送指示，还可以通过以下方式实现。如图3d所示，本申请实施例提供的下行数据早传方法之七的具体过程如下所述。
S301d、第三网络设备向第二网络设备发送下行数据通知消息，第二网络设备从第三网络设备接收下行数据通知消息。
该下行数据通知消息中还可携带终端的标识，例如，S-TMSI。
S302d、第二网络设备向第一网络设备发送寻呼消息，第一网络设备从第二网络设备接收寻呼消息。
该寻呼消息中还可携带终端的标识，例如，S-TMSI。
S303d、第一网络设备向终端发送寻呼消息，终端接收第一网络设备发送的寻呼消息。
S304d、终端向第一网络设备发送消息1(Msg1)，第一网络设备从终端接收消息1(Msg1)，该消息1为随机接入前导码(random access preamble)。
S305d、第一网络设备向终端发送消息2(Msg2)，终端从第一网络设备接收消息2。
其中，该消息2为随机接入响应(random access response)。
S306d、终端向第一网络设备发送第一RRC消息，第一网络设备从终端接收第一RRC消息。
S307d、第三网络设备向第二网络设备发送下行数据，第二网络设备接收第三网络设备发送的下行数据。
该下行数据中携带指示，该指示的含义可以参考上文中的描述。
S308d、第二网络设备将下行数据封装在NAS消息中，第二网络设备通过下行NAS传输将下行数据发送给第一网络设备，第一网络设备接收第二网络设备发送的下行NAS消息。该NAS消息还携带指示，该指示的含义可以参考上文中的描述。
S309d、第一网络设备向终端发送第二RRC消息，终端从第一网络设备接收第二RRC消息。
其中，第二RRC消息中携带下行数据。
具体的，第一网络设备将接收到的NAS消息封装在第二RRC消息中，将第二RRC消息发送给终端。
通过上述下行数据早传方法之七，第二网络设备可以根据第三网络设备发送的指示，将终端的下行数据封装于NAS消息中经由第一网络设备发送给终端，不需要建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
以下结合上述下行数据早传方法之五、下行数据早传方法之六和下行数据早传方法之七，示例性的对第一RRC消息和第二RRC消息可能的功能或含义给予说明，以下说明适用于这三种下行数据早传方法之中。
第一RRC消息为RRC数据早传请求(RRC early data request)消息，用于请求上行数 据早传，该RRC数据早传请求消息中可能携带dedicated Info NAS，dedicated Info NAS本来的功能是用于承载早传的上行数据，在下行数据早传场景中，假设终端没有上行数据，则可以将dedicated Info NAS置为空NULL，用于指示未携带上行数据。第二RRC消息为RRC数据早传完成(RRC early data complete)消息，用于携带早传的下行数据。
或者，第一RRC消息为RRC连接请求消息。用于请求建立RRC连接。第二RRC消息为RRC数据早传完成消息，用于携带早传的下行数据。
或者，第一RRC消息为RRC连接请求消息，用于请求建立RRC连接。第二RRC消息为RRC连接释放消息，用于通知释放RRC连接，以及用于携带早传的下行数据。
基于上述描述，以下结合几种具体的应用场景，对本申请实施例提供的下行数据早传方法做进一步详细的说明。以下举例中，以第一网络设备(即接入网设备)为基站、第二网络设备(即第一核心网设备)为MME、第三核心网设备(即第二核心网设备)为S-GW为例进行介绍。
以下几种应用场景中，在开始下面所述的步骤之前，终端处于被挂起的状态。具体的，当基站判断出终端没有上下行数据时，基站向MME请求将该终端挂起(即suspend)，挂起即基站释放与终端的RRC连接，但基站不释放终端的上下文信息。当基站接收到MME的肯定响应时，即允许该终端挂起，基站向终端发送RRC连接释放(RRC connection release)消息，并在该RRC连接释放消息中指示该终端挂起。终端收到该RRC连接释放消息后，保存基站对该终端的配置信息。此时终端处于空闲态(即idle态)。当网络侧有终端的下行数据时，通过以下过程执行下行数据的早传。
图4a示出了本申请实施例提供的下行数据早传方法的实现方式之一，该实现方式之一基于上述图2a所示的下行数据早传方法之一的描述，下面详细介绍一下该实现方式之一。
S401a、S-GW向MME发送下行数据通知消息(downlink data notification)，MME接收S-GW发送的下行数据通知消息。
具体的，核心网侧的S-GW有终端的下行数据到达时，会触发下行数据通知消息的发送。该下行数据通知消息中携带终端的标识，例如，标识为EPS系统暂时移动用户标识(EPS TMSI，S-TMSI)，其中EPS为演进分组系统(evolved packet system)。
S402a、MME接收到S-GW发送的下行数据通知消息后，向基站发送寻呼消息，基站接收MME发送的寻呼消息(即paging消息)，该寻呼消息用于指示基站寻呼终端。
S403a、基站接收到MME发送的寻呼消息后，以广播形式发送寻呼消息。
处于idle态的终端会周期性的监听寻呼消息，当终端监听到基站发送的寻呼消息并且确认该寻呼消息中携带自己的标识时，终端触发以下步骤。
S404a、终端向基站发送随机接入前导码(random access preamble)，基站接收终端发送的随机接入前导码。
其中，基站通过广播消息广播给所有终端若干个随机接入前导码，该终端从基站广播的若干个随机接入前导码中随机选择一个，并在基站广播的用于发送随机接入前导码的资源中随机选择一份资源，在选择的资源上发送选择的随机接入前导码。
S405a、基站向终端发送随机接入响应(random access response,RAR)，终端接收基站发送的随机接入响应。
具体的，基站在随机接入前导码的资源上监听终端发送的随机接入前导码，当检测到某个随机接入前导码时，向终端发送RAR。其中，RAR中包含：终端发送Msg3的定时 (timing advanced,TA)和终端发送Msg3的上行资源(UL grant)。
S406a、终端恢复信令无线承载(Signaling Radio Bearer，SRB)。
具体的，终端恢复SRB1，其中，SRB1用于发送和接收RRC消息，以及用于接收SRB2建立之前的NAS消息。
S407a、终端向基站发送消息3(即Msg3)，基站接收终端发送的Msg3。
其中，Msg3可以是RRC连接恢复请求(RRC connection resume request)消息，可选的，Msg3中还包含指示，该指示的含义可以参见上文例1～例7的描述。。
可选的，该RRC连接恢复请求消息中还携带以下信息：恢复标识(resume ID)，恢复原因(resume cause)，short resume MAC-I。其中，resume ID用于标识被挂起的终端，也就是用于标识发送RRC连接恢复请求消息的该终端；resume cause用于指示该终端恢复连接的原因，例如，resume cause的值为被叫接入(mobile terminating-Access，mt-Access)，或者，resume cause的值为新增加的值，该新增加的值用于指示恢复连接的原因为传输单个下行数据；short resumeMAC-I用于对Msg3进行完整性保护，以防止Msg3被篡改。
S408a、基站根据S407接收到的指示，向MME发送终端上下文恢复请求(UE context resume request)消息，MME接收基站发送的终端上下文恢复请求消息。
其中，终端上下文恢复请求消息用于请求恢复该终端的上下文信息。
S409a、MME与S-GW交互承载修改(modify bearer)消息。
S410a、MME向基站发送上下文恢复响应消息(UE context resume response)，基站接收MME发送的上下文恢复响应消息。
S411a、基站在接收到MME发送的上下文恢复响应消息之后，恢复终端的上下文信息，其中，该终端的上下文信息中包含NCC，这里记为第一NCC，第一NCC可以来自于终端上一次接收到的Msg4。基站使用第一NCC推演新的密钥，记为第一密钥，用K 1 RRCenc表示，第一密钥用于对下行数据进行加密。该终端的上下文信息中还包含旧密钥，记为第三密钥，用K 3 RRCint表示，第三密钥用于对RRC连接释放消息进行完整性保护。
基站还可以使用第一NCC推演第二密钥和第四密钥，第二密钥用K 2 RRCint表示，第四密钥用K 4 RRCenc表示。第二密钥用于对RRC连接释放消息进行完整性保护，第四密钥用于对RRC连接释放消息进行加密。
S412a、S-GW向基站发送下行数据，基站接收S-GW发送的下行数据。
根据终端的业务单一的特点，默认仅有一个下行数据包。
可选的，本步骤中S-GW向基站发送下行数据中携带指示，该指示所指示的含义可以参考上文中的描述。具体的，该下行数据包的GTP-U协议报文的报头携带该指示。
需要说明的是，S410a和S412a没有严格的执行顺序。S-GW在执行完S409a之后即可执行本步骤。
S413a、基站与MME交互挂起终端的上下文的过程，MME与S-GW交互承载修改(modify bearer)消息的过程。
具体的，基站根据S407a或S412a中接收到的指示，发起挂起终端的上下文的过程以及交互承载修改消息的过程。
S414a、基站向终端发送消息4(Msg4)，终端接收基站发送的Msg4。
其中，Msg4中包含终端的下行数据，Msg4中还包含RRC连接释放(RRC connection release)消息。基站将RRC连接释放消息与下行数据封装在一条消息(即Msg4)中发送 给终端，终端接收基站发送的该消息，终端获得RRC连接释放消息与下行数据。
基站可以采用方法1进行完整性保护和加密。具体地，基站使用第三密钥对RRC连接释放消息进行完整性保护，并使用第一密钥对下行数据进行加密。将执行完整性保护的RRC连接释放消息和加密的下行数据携带于消息4中发送给终端。
或者，基站也可以采用方法2对进行完整性保护和加密。具体地，基站使用第二密钥对RRC连接释放消息进行完整性保护，使用第一密钥对下行数据进行加密。将执行完整性保护和加密的RRC连接释放消息和加密的下行数据携带于消息4中发送给终端。
基站根据接收到的指示确定下行数据早传，或者确定终端发送的下行数据可以承载在一个TB中发送给终端，因此不需要终端进入RRC连接状态，基站在向终端发送RRC连接释放消息中携带该下行数据。
基站可以但不限于通过以下两种方法来确定向终端发送的下行数据可以一次发送给终端(即可以承载在一个TB中发送给终端)。需要说明的是，本部分描述可以适用于上文中各个下行数据早传方法，基站即上文各个实施例中的第一网络设备，第一网络设备也可以通过该方法确定向终端发送的下行数据可以一次发送给终端，从而向通过一条消息将下行数据发送给终端。
第一种方法：基站可以根据S411中接收到的S-GW发送的指示或者根据S407中接收到的终端发送的指示，确定下行数据可以一次发送给终端，从而向终端发送RRC连接释放消息。
第二种方法：基站在S412a接收到S-GW发送的下行数据时启动定时器，在定时器超时时，基站还未再次接收到下行数据，则基站确定本次S-GW下发给终端的下行数据只有一个下行数据包，确定下行数据可以一次发送给终端；或者，在定时器超时时，基站接收到多个下行数据包，但基站确定该多个下行数据包可以通过一个TB发送给终端。并且基站接收到的下行数据中携带指示，该指示用于指示终端在接收到下行数据后不会有上行的响应消息或上行数据。则在这些情况下，不需要终端进入连接态，从而基站向终端发送RRC连接释放消息。
本步骤中，RRC连接释放消息中携带恢复标识(resume ID)和释放原因(release cause)。可选，还可以在RRC连接释放消息中携带NCC。终端通过S406a恢复的SRB1来接收RRC连接释放消息。
其中，resume ID用于标识被挂起的终端，即S407发送RRC连接恢复请求消息的该终端，该resume ID与S407a中RRC连接恢复请求消息中的resume ID相同。release cause用于指示该释放该终端上下文的原因，例如，release cause的值可以是RRC挂起(即rrc-suspend)。终端保存RRC连接释放消息中携带的NCC，该NCC可以用于下次上行数据早传和/或下行数据早传。
S415a、终端恢复上下文信息。
具体的，终端恢复的上下文信息中包括旧密钥和第一NCC，同样的，该旧密钥可以记为第三密钥。在方法1中，第三密钥可以用于对RRC连接释放消息进行完整性保护校验，第一NCC可以用于推演第一密钥，第一密钥用于对下行数据进行解密。终端恢复的上下文信息中还可以包括SRB2、数据无线承载(data radio bearer，DRB)。第一NCC可以来自于终端上一次接收到的Msg4。
或者，第一NCC可以用于推演第一密钥，第一密钥用于对下行数据进行解密，第一 NCC还可以用于推演第二密钥。第二密钥用于对RRC连接释放消息进行完整性保护校验。
终端向基站发送RRC连接恢复请求消息，并接收到了基站回复的RRC连接释放消息和下行数据，则终端确定只有一个下行数据包，恢复上下文信息。其中，SRB2用于承载RRC消息以及NAS消息。
S416a、终端对RRC连接释放消息进行完整性保护校验，以及对下行数据进行解密。
具体的，若采用方法1，则终端使用S414中恢复的第三密钥对RRC连接释放消息进行完整性保护校验，并使用第一密钥对下行数据进行解密；
若采用方法2，则终端使用S414推演的第二密钥对RRC连接释放消息进行完整性保护校验，使用第一密钥对下行数据进行解密。
需要说明的是，基站与终端采用的加解密和完整性保护的方法是一致的。
S417a、终端将上下文信息挂起，进入空闲态(idle态)。
具体地，终端将承载配置和安全配置挂起，例如终端将SRB、DRB、安全上下文挂起。
通过上述下行数据早传方法的实现方式之一，终端向接入网设备(即基站)发送下行数据早传的指示，基站可以将下行数据可以与RRC消息一并发送给终端，例如，RRC消息可以是RRC连接释放消息，对于仅有一个下行数据包的终端，该终端可以不用进入连接态，在空闲态就能接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
图4b示出了本申请实施例提供的下行数据早传方法的实现方式之二，该实现方式之二基于上述图2a所示的下行数据早传方法之一的描述，下面详细介绍一下该实现方式之二。
S401b～S405b的步骤与S401a～S405a的步骤相同，可以参照上文中这几个步骤的描述，在此不再赘述。
S406b、终端恢复上下文信息。
具体地，终端恢复的上下文信息中至少包括第一NCC，第一NCC用于推演第一密钥、第二密钥和第四密钥。第一密钥用于对下行数据进行解密，第二密钥用于对RRC连接释放消息进行完整性保护校验，第四密钥用于对RRC连接释放消息进行解密。
可选的，终端恢复的上下文信息还可以包括SRB1、SRB2和DRB，其中，SRB1用于发送和接收RRC消息，以及用于接收SRB2建立之前的NAS消息。
S407b～S410b的步骤与S407b～S410b的步骤相同，可以参照上文中这几个步骤的描述，在此不再赘述。
S411b、基站在接收到MME发送的上下文恢复响应消息之后，恢复终端的上下文信息。
具体的，基站恢复的终端的上下文信息中包含第一NCC，基站使用第一NCC推演新的第一密钥、第二密钥和第四密钥，第二密钥用于对RRC连接释放消息进行完整性保护，第四密钥用于对RRC连接释放消息进行加密。
S412b～S413b的步骤与S412a～S413a的步骤相同，可以参照上文中这几个步骤的描述，在此不再赘述。
S414b、基站向终端发送消息4(Msg4)，终端接收基站发送的Msg4。
其中，Msg4中包含终端的下行数据，Msg4中还包含RRC连接释放(RRC connection release)消息。
具体的，本步骤与S414a的不同之处在于，基站对消息4的完整性保护和加密的过程 不同。基站使用第一密钥对下行数据进行加密，使用第二密钥对RRC连接释放消息进行完整性保护，使用第四密钥对RRC连接释放消息进行加密，将执行完整性保护和加密的RRC连接释放消息和加密的下行数据携带于消息4中发送给终端。
其余对本步骤的描述与S414a相同，可参照S414a。
S415b、终端对对RRC连接释放消息进行完整性保护校验，以及对下行数据进行解密。
具体地，终端使用第二密钥对RRC连接释放消息进行完整性保护校验，使用推演的第四密钥用于对RRC连接释放消息进行解密，使用第一密钥对下行数据进行解密。
若终端在S406b未执行恢复SRB2和DRB，那么终端可在接收到消息4之后恢复SRB2和DRB。
S416b、同S417a。
通过上述下行数据早传方法的实现方式之二，终端向接入网设备(即基站)发送下行数据早传的指示，基站可以将下行数据可以与RRC消息一并发送给终端，例如，RRC消息可以是RRC连接释放消息，对于仅有一个下行数据包的终端，该终端可以不用进入连接态，在空闲态就能接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
图4c示出了本申请实施例提供的下行数据早传方法的实现方式之三，该实现方式之三基于上述图2a所示的下行数据早传方法之一的描述，下面详细介绍一下该实现方式之三。
S401c～S410c的步骤与S401a～S410a的步骤相同，可以参照上文中这几个步骤的描述，在此不再赘述。
S411c、基站在接收到MME发送的上下文恢复响应消息之后，恢复终端的上下文信息。
具体地，基站恢复的终端的上下文信息中包含旧密钥(即第三密钥)，在上文的方法4中，第三密钥用于对RRC连接释放消息进行完整性保护。
S412c～S413c的步骤与S412a～S413a的步骤相同，在此不再赘述。
S414c、基站向终端发送消息4(Msg4)，终端接收基站发送的Msg4。
本步骤可以参考S414a，本步骤与S414a的不同之处在于基站对消息4的完整性保护和加密的过程不同。
具体地，基站可以采用上文中的方法4，即，基站在Msg4中携带第二NCC，使用第二NCC推演第五密钥。基站使用第三密钥对RRC连接释放消息进行完整性保护，并使用第五密钥对下行数据进行加密，将执行完整性保护的RRC连接释放消息和加密的下行数据携带于消息4中发送给终端。
或者，基站采用上文中的方法5，即，基站在Msg4中携带第二NCC，使用第二NCC推演第五密钥和第六密钥。基站使用第六密钥对RRC连接释放消息进行完整性保护，并使用第五密钥对下行数据进行加密，将执行完整性保护的RRC连接释放消息和加密的下行数据携带于消息4中发送给终端。
S415c、终端恢复上下文信息。
具体的，终端恢复的上下文信息中包括旧密钥，即第三密钥。在上文的方法4中，第三密钥可以用于对RRC连接释放消息进行完整性保护校验。
S416c、终端对RRC连接释放消息进行完整性保护校验，以及对下行数据进行解密。
具体地，若采用上文中的方法4，则终端使用第三密钥对RRC连接释放消息进行完整性保护校验。终端在接收到的Msg4中获取第二NCC，使用第二NCC推演第五密钥，使 用第五密钥对下行数据进行解密。
若采用上文中的方法5，则终端在接收到的Msg4中获取第二NCC，使用第二NCC推演第五密钥和第六密钥，使用第六密钥对RRC连接释放消息进行完整性保护校验，使用第五密钥对下行数据进行解密。
S417c同S417a。
需要说明的是，基站与终端采用的加解密和完整性保护的方法是一致的。
通过上述下行数据早传方法的实现方式之三，终端向接入网设备(即基站)发送下行数据早传的指示，基站可以将下行数据可以与RRC消息一并发送给终端，例如，RRC消息可以是RRC连接释放消息，对于仅有一个下行数据包的终端，该终端可以不用进入连接态，在空闲态就能接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
图5a示出了本申请实施例提供的下行数据早传方法的实现方式之四，该实现方式之四基于上述图2b所示的下行数据早传方法之二的描述，下面详细介绍一下该实现方式之四。
S501a、S-GW向MME发送下行数据通知消息(downlink data notification)，MME接收S-GW发送的下行数据通知消息。
其中，下行数据通知消息中携带指示，该指示的含义可以参考上文中的描述。
核心网侧的S-GW有终端的下行数据到达时，会触发下行数据通知消息的发送。该下行数据通知消息中还会携带终端的标识，例如，标识为S-TMSI。
S502a、MME接收到S-GW发送的下行数据通知消息后，向基站发送寻呼消息，基站接收MME发送的寻呼消息(即paging消息)。
该寻呼消息用于指示基站寻呼终端。该寻呼消息中会携带终端的标识，例如，标识为S-TMSI。该寻呼消息中也会携带指示，该指示的含义可以参考上文中的描述。
S503a、基站接收到MME发送的寻呼消息后，以广播形式发送寻呼消息。
处于idle态的终端会周期性的监听寻呼消息，当终端监听到基站发送的寻呼消息并且确认该寻呼消息中携带自己的标识时，终端触发以下步骤。
S504a与S404a相同，S505a与S405a相同，S506a与S406a相同，在此不再赘述。
S507a、终端向基站发送消息3(即Msg3)，基站接收终端发送的Msg3。
Msg3可以是RRC连接恢复请求(RRC connection resume request)消息。该RRC连接恢复请求消息中还可以携带以下信息：恢复标识(resume ID)，恢复原因(resume cause)，short resume MAC-I。其中，resume ID用于标识被挂起的终端，也就是用于标识发送RRC连接恢复请求消息的该终端；resume cause用于指示该终端恢复连接的原因，例如，resume cause的值为被叫接入(mobile terminating-Access，mt-Access)，或者，resume cause的值为新增加的值，该新增加的值用于指示恢复连接的原因为传输单个下行数据；short resume MAC-I用于对Msg3进行完整性保护，以防止Msg3被篡改。
S508a、基站在接收到RRC连接恢复请求之后，根据S502a接收到的寻呼消息中携带的指示，向MME发送终端上下文恢复请求(UE context resume request)消息，MME接收基站发送的终端上下文恢复请求消息。
具体地，S502a中的寻呼消息中携带的终端的标识信息为S-TMSI，或者，S-TMSI和Resume ID，S507a中的RRC连接恢复请求中携带的终端的标识为resume ID。基站根据S-TMSI与resume ID的映射关系，确定S502a步骤中发送RRC连接恢复请求的终端为有 单个下行数据的终端，于是基站并不会向终端发送RRC连接恢复响应消息，而是向MME发送上下文恢复请求消息，以请求该终端的下行数据。
S509a、MME与S-GW交互承载修改(modify bearer)消息。
S510a～S517a与S410a～S417a相同，在此不再赘述。
通过上述下行数据早传方法的实现方式之四，网络侧在下行数据通知消息和寻呼消息中发送下行数据早传的指示，则基站可以将下行数据与RRC消息一并发送给终端，例如，RRC消息可以是RRC连接释放消息，对于仅有一个下行数据包的终端，该终端可以不用进入连接态，在空闲态就能接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
图5b示出了本申请实施例提供的下行数据早传方法的实现方式之五，该实现方式之五基于上述图2b所示的下行数据早传方法之二的描述，下面详细介绍一下该实现方式之五。
S501b～S505b的步骤与S501a～S505a的步骤相同，可以参照上文中这几个步骤的描述，在此不再赘述。
S506b同S406b。
S507b同S507a。
S508b～S516b的步骤与S408b～S416b的步骤相同，可以参照图4b所示的实施例中对这几个步骤的描述，在此不再赘述。
通过上述下行数据早传方法的实现方式之五，网络侧在下行数据通知消息和寻呼消息中发送下行数据早传的指示，则基站可以将下行数据与RRC消息一并发送给终端，例如，RRC消息可以是RRC连接释放消息，对于仅有一个下行数据包的终端，该终端可以不用进入连接态，在空闲态就能接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
图5c示出了本申请实施例提供的下行数据早传方法的实现方式之六，该实现方式之六基于上述图2b所示的下行数据早传方法之二的描述，下面详细介绍一下该实现方式之六。
S501c～S510c的步骤与S501a～S510a的步骤相同，可以参照上文中这几个步骤的描述，在此不再赘述。
S511c～S517c的步骤与S411c～S417c的步骤相同，可以参照图4b所示的实施例中对这几个步骤的描述，在此不再赘述。
通过上述下行数据早传方法的实现方式之六，网络侧在下行数据通知消息和寻呼消息中发送下行数据早传的指示，则基站可以将下行数据与RRC消息一并发送给终端，例如，RRC消息可以是RRC连接释放消息，对于仅有一个下行数据包的终端，该终端可以不用进入连接态，在空闲态就能接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
图6a示出了本申请实施例提供的下行数据早传方法的实现方式之七，该实现方式之七基于上述图2c所示的下行数据早传方法之三的描述，下面详细介绍一下该实现方式之七。
S601a～S606a同S501a～S506a。
S607a同S407a。
S608a～S617a与S508a～S517a相同，在此不再赘述。
通过上述下行数据早传方法的实现方式之七，基站可以根据终端以及核心网设备发送 的指示，在随机接入过程中将单个下行数据发送给终端，并需要不建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
图6b示出了本申请实施例提供的下行数据早传方法的实现方式之八，该实现方式之八基于上述图2c所示的下行数据早传方法之三的描述，下面详细介绍一下该实现方式之八。
S601b～S606b同S501b～S506b。
S607b同S407b。
S608b～S616b与S508b～S516b相同，在此不再赘述。
通过上述下行数据早传方法的实现方式之八，基站可以根据终端以及核心网设备发送的指示，在随机接入过程中将单个下行数据发送给终端，并需要不建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
图6c示出了本申请实施例提供的下行数据早传方法的实现方式之九，该实现方式之九基于上述图2c所示的下行数据早传方法之三的描述，下面详细介绍一下该实现方式之九。
S601c～S606c同S501c～S506c。
S607c同S407c。
S608c～S617c与S508c～S517c相同，在此不再赘述。
通过上述下行数据早传方法的实现方式之九，基站可以根据终端以及核心网设备发送的指示，在随机接入过程中将单个下行数据发送给终端，并需要不建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
图7a示出了本本申请实施例提供的下行数据早传方法的实现方式之十，该实现方式之十基于上述图3a所示的下行数据早传方法之四的描述，下面详细介绍一下该实现方式之十。
S701a、S-GW向MME发送下行数据通知消息(downlink data notification)，MME接收S-GW发送的下行数据通知消息。
具体的，核心网侧的S-GW有终端的下行数据到达时，会触发下行数据通知消息的发送。该下行数据通知消息中携带终端的标识，例如，标识为S-TMSI。
S702a、MME接收到S-GW发送的下行数据通知消息后，向基站发送寻呼消息，基站接收MME发送的寻呼消息(即paging消息)，该寻呼消息用于指示基站寻呼终端。
S703a、基站接收到MME发送的寻呼消息后，以广播形式发送寻呼消息。
处于idle态的终端会周期性的监听寻呼消息，当终端监听到基站发送的寻呼消息并且确认该寻呼消息中携带自己的标识时，终端触发以下步骤。
S704a、终端向基站发送随机接入前导码(random access preamble)，基站接收终端发送的随机接入前导码。
其中，基站通过广播消息广播给所有终端若干个随机接入前导码，该终端从基站广播的若干个随机接入前导码中随机选择一个，并在基站广播的用于发送随机接入前导码的资源中随机选择一份资源，在选择的资源上发送选择的随机接入前导码。
S705a、基站向终端发送随机接入响应(random access response,RAR)，终端接收基站 发送的随机接入响应。
具体的，基站在随机接入前导码的资源上监听终端发送的随机接入前导码，当检测到某个随机接入前导码时，向终端发送RAR。其中，RAR中包含：终端发送Msg3的定时(timing advanced,TA)和终端发送Msg3的上行资源(UL grant)。
S706a、终端向基站发送RRC数据早传请求(RRC early data request)消息，基站从终端接收RRC数据早传请求消息。
其中，RRC数据早传请求消息中携带一个指示，记为第一指示，该第一指示所指示的含义可以参考上文中的描述。该第一指示指示的含义可以是single packet，或者single DL data，也可以通过dedicated Info NAS来指示，其中dedicated Info NAS本来的功能是用于承载早传的上行数据，在下行数据早传场景中，假设终端没有上行数据，此时RRC数据早传请求消息是用于通知下行数据早传的，所以可以将dedicated Info NAS置为空NULL，用于指示未携带上行数据，进一步指示为下行数据早传。RRC early data request消息还可以携带其它信息，该消息携带的其它信息与现有技术相同。
S707a、基站向MME发送终端初始化(Initial UE Message)消息，MME从基站接收终端初始化消息。
其中，终端初始化消息用于初始化该终端的上下文信息。该终端初始化消息中携带指示，记为第二指示，第二指示的指示含义同本文中对指示的解释。
S708a、MME与S-GW交互承载修改(modify bearer)消息。
S709a、S-GW向MME发送下行数据，MME接收S-GW发送的下行数据。
S710a、MME将下行数据封装在NAS消息中，MME通过下行NAS传输(DL NAS transport)将下行数据发送给基站，基站从MME接收NAS消息。
S711a、基站向终端发送RRC数据早传完成(RRC early data complete)消息，终端从基站接收RRC数据早传完成(RRC early data complete)消息。
该RRC数据早传完成(RRC early data complete)消息中携带下行数据。具体的，基站将接收到的NAS消息封装在RRC数据早传完成(RRC early data complete)消息中，发送给终端。终端从接收到的RRC数据早传完成(RRC early data complete)消息中获取NAS消息，从而获取下行数据。
通过上述下行数据早传方法的实现方式之十，MME可以根据终端发送的指示，将终端的下行数据封装于NAS消息中经由基站发送给终端，不需要建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
图7b示出了本申请实施例提供的下行数据早传方法的实现方式之十一，该实现方式之十一基于上述图3a所示的下行数据早传方法之四的描述，下面详细介绍一下该实现方式之十一。
S701b～S705b同S701a～S705a，可以参见上文中相关步骤的描述，在此不再赘述。
S706b、终端向基站发送RRC连接请求消息，用于请求建立RRC连接。基站从终端接收RRC连接请求消息。
该RRC连接请求消息中携带第一指示，该第一指示的功能和所指示的含义可以参考上文中的描述。例如，该第一指示指示的含义可以是single packet，或者single DL data。
S707b～S711b同S707a～S711a，可以参见上文中相关步骤的描述，在此不再赘述。
通过上述下行数据早传方法的实现方式之十一，MME可以根据终端发送的指示，将终端的下行数据封装于NAS消息中经由基站发送给终端，不需要建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
图7c示出了本本申请实施例提供的下行数据早传方法的实现方式之十二，该实现方式之十二基于上述图3a所示的下行数据早传方法之四的描述，下面详细介绍一下该实现方式之十二。
S701c～S705c同S701a～S705a，可以参见上文中相关步骤的描述，在此不再赘述。
S706c、终端向基站发送RRC连接请求(RRC connection request)消息，用于请求建立RRC连接。该RRC连接请求消息中携带第一指示，该第一指示的功能和所指示的含义可以参考上文中的描述。例如，该第一指示指示的含义可以是single packet，或者single DL data。
S707c～S710c同S707a～S710a，可以参见上文中相关步骤的描述，在此不再赘述。
S711c、基站向终端发送RRC连接释放消息，终端从基站接收RRC连接释放消息。
该RRC连接释放消息(RRC connection release)中携带下行数据。具体的，基站将接收到的NAS消息封装在RRC连接释放消息中发送给终端。终端从接收到的RRC连接释放消息中获取NAS消息，从而获取下行数据。
通过上述下行数据早传方法的实现方式之十二，MME可以根据终端发送的指示，将终端的下行数据封装于NAS消息中经由基站发送给终端，不需要建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
图8a示出了本本申请实施例提供的下行数据早传方法的实现方式之十三，该实现方式之十三基于上述图3b所示的下行数据早传方法之五的描述，下面详细介绍一下该实现方式之十三。
S801a、S-GW向MME发送下行数据通知消息(downlink data notification)，MME接收S-GW发送的下行数据通知消息。
其中，下行数据通知消息中携带指示，该指示的含义可以参考上文中的描述。
核心网侧的S-GW有终端的下行数据到达时，会触发下行数据通知消息的发送。该下行数据通知消息中还会携带终端的标识，例如，标识为S-TMSI。
S802a、MME接收到S-GW发送的下行数据通知消息后，向基站发送寻呼消息，基站接收MME发送的寻呼消息(即paging消息)。
该寻呼消息用于指示基站寻呼终端。该寻呼消息中会携带终端的标识，例如，标识为S-TMSI。该寻呼消息中也会携带指示，该指示的含义可以参考上文中的描述。
S803a、基站接收到MME发送的寻呼消息后，以广播形式发送寻呼消息。
可选的，在本步骤发送的寻呼消息中也可以携带指示，该指示的含义可以参考上文中的描述。
处于idle态的终端会周期性的监听寻呼消息，当终端监听到基站发送的寻呼消息并且确认该寻呼消息中携带自己的标识时，终端触发以下步骤。
S804a、终端向基站发送随机接入前导码(random access preamble)，基站接收终端发送的随机接入前导码。
其中，基站通过广播消息广播给所有终端若干个随机接入前导码，该终端从基站广播的若干个随机接入前导码中随机选择一个，并在基站广播的用于发送随机接入前导码的资源中随机选择一份资源，在选择的资源上发送选择的随机接入前导码。
S805a、基站向终端发送随机接入响应(random access response,RAR)，终端接收基站发送的随机接入响应。
具体的，基站在随机接入前导码的资源上监听终端发送的随机接入前导码，当检测到某个随机接入前导码时，向终端发送RAR。其中，RAR中包含：终端发送Msg3的定时(timing advanced,TA)和终端发送Msg3的上行资源(UL grant)。
S806a、终端向基站发送RRC数据早传请求(RRC early data request)消息，基站从终端接收RRC数据早传请求消息。
RRC数据早传请求(RRC early data request)消息，用于请求上行数据早传，该RRC数据早传请求消息中可能携带dedicated Info NAS，dedicated Info NAS本来的功能是用于承载早传的上行数据，在下行数据早传场景中，假设终端没有上行数据，则可以将dedicated Info NAS置为空NULL，用于指示未携带上行数据。
S807a、基站向MME发送终端初始化(Initial UE Message)消息，MME从基站接收终端初始化消息。
S808a、MME与S-GW交互承载修改(modify bearer)消息。
S809a、S-GW向MME发送下行数据，MME接收S-GW发送的下行数据。
S810a、MME将下行数据封装在NAS消息中，MME通过下行NAS传输(DL NAS transport)将下行数据发送给基站，基站从MME接收NAS消息。
S811a、基站向终端发送RRC数据早传完成(RRC early data complete)消息，终端从基站接收RRC数据早传完成(RRC early data complete)消息。
该RRC数据早传完成(RRC early data complete)消息中携带下行数据。具体的，基站将接收到的NAS消息封装在RRC数据早传完成(RRC early data complete)消息中，发送给终端。终端从接收到的RRC数据早传完成(RRC early data complete)消息中获取NAS消息，从而获取下行数据。
通过上述下行数据早传方法的实现方式之十三，MME可以根据SGW发送的指示，将终端的下行数据封装于NAS消息中经由基站发送给终端，不需要建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
图8b示出了本申请实施例提供的下行数据早传方法的实现方式之十四，该实现方式之十四基于上述图3b所示的下行数据早传方法之五的描述，下面详细介绍一下该实现方式之十四。
S801b～S805b同S801a～S805a，可以参见上文中相关步骤的描述，在此不再赘述。
S806b、终端向基站发送RRC连接请求消息，用于请求建立RRC连接。基站从终端接收RRC连接请求消息。
S807b～S811b同S807a～S811a，可以参见上文中相关步骤的描述，在此不再赘述。
通过上述下行数据早传方法的实现方式之十四，MME可以根据SGW发送的指示，将终端的下行数据封装于NAS消息中经由基站发送给终端，不需要建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降 低终端的功耗。
图8c示出了本申请实施例提供的下行数据早传方法的实现方式之十五，该实现方式之十五基于上述图3b所示的下行数据早传方法之五的描述，下面详细介绍一下该实现方式之十五。
S801c～S805c同S801a～S805a，可以参见上文中相关步骤的描述，在此不再赘述。
S806c、终端向基站发送RRC连接请求(RRC connection request)消息，用于请求建立RRC连接。
S807c～S810c同S807a～S810a，可以参见上文中相关步骤的描述，在此不再赘述。
S811c、基站向终端发送RRC连接释放消息，终端从基站接收RRC连接释放消息。
该RRC连接释放消息(RRC connection release)中携带下行数据。具体的，基站将接收到的NAS消息封装在RRC连接释放消息中发送给终端。终端从接收到的RRC连接释放消息中获取NAS消息，从而获取下行数据。
通过上述下行数据早传方法的实现方式之十五，MME可以根据SGW发送的指示，将终端的下行数据封装于NAS消息中经由基站发送给终端，不需要建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
图9a示出了本申请实施例提供的下行数据早传方法的实现方式之十六，该实现方式之十六基于上述图3c所示的下行数据早传方法之六的描述，下面详细介绍一下该实现方式之十六。
S901a、S-GW向MME发送下行数据通知消息(downlink data notification)，MME接收S-GW发送的下行数据通知消息。
其中，下行数据通知消息中携带指示，该指示的含义可以参考上文中的描述。
核心网侧的S-GW有终端的下行数据到达时，会触发下行数据通知消息的发送。该下行数据通知消息中还会携带终端的标识，例如，标识为S-TMSI。
S902a、MME接收到S-GW发送的下行数据通知消息后，向基站发送寻呼消息，基站接收MME发送的寻呼消息(即paging消息)。
该寻呼消息用于指示基站寻呼终端。该寻呼消息中会携带终端的标识，例如，标识为S-TMSI。
S903a、基站接收到MME发送的寻呼消息后，以广播形式发送寻呼消息。
可选的，在本步骤发送的寻呼消息中也可以携带指示，该指示的含义可以参考上文中的描述。
处于idle态的终端会周期性的监听寻呼消息，当终端监听到基站发送的寻呼消息并且确认该寻呼消息中携带自己的标识时，终端触发以下步骤。
S904a、终端向基站发送随机接入前导码(random access preamble)，基站接收终端发送的随机接入前导码。
其中，基站通过广播消息广播给所有终端若干个随机接入前导码，该终端从基站广播的若干个随机接入前导码中随机选择一个，并在基站广播的用于发送随机接入前导码的资源中随机选择一份资源，在选择的资源上发送选择的随机接入前导码。
S905a、基站向终端发送随机接入响应(random access response,RAR)，终端接收基站发送的随机接入响应。
具体的，基站在随机接入前导码的资源上监听终端发送的随机接入前导码，当检测到某个随机接入前导码时，向终端发送RAR。其中，RAR中包含：终端发送Msg3的定时(timing advanced,TA)和终端发送Msg3的上行资源(UL grant)。
S906a、终端向基站发送RRC数据早传请求(RRC early data request)消息，基站从终端接收RRC数据早传请求消息。
RRC数据早传请求(RRC early data request)消息，用于请求上行数据早传，该RRC数据早传请求消息中可能携带dedicated Info NAS，dedicated Info NAS本来的功能是用于承载早传的上行数据，在下行数据早传场景中，假设终端没有上行数据，则可以将dedicated Info NAS置为空NULL，用于指示未携带上行数据。
S907a、基站向MME发送上下文恢复请求(UE context resume request)消息，MME从基站接收上下文恢复请求消息。
S908a、MME与S-GW交互承载修改(modify bearer)消息。
S909a、S-GW向MME发送下行数据，MME接收S-GW发送的下行数据。
S910a、MME将下行数据封装在NAS消息中，MME通过下行NAS传输(DL NAS transport)将下行数据发送给基站，基站从MME接收NAS消息。
该NAS消息还携带指示，该指示的含义可以参考上文中的描述。
S911a、基站向终端发送RRC数据早传完成(RRC early data complete)消息，终端从基站接收RRC数据早传完成(RRC early data complete)消息。
该RRC数据早传完成(RRC early data complete)消息中携带下行数据。具体的，基站将接收到的NAS消息封装在RRC数据早传完成(RRC early data complete)消息中，发送给终端。终端从接收到的RRC数据早传完成(RRC early data complete)消息中获取NAS消息，从而获取下行数据。
通过上述下行数据早传方法的实现方式之十六，MME可以根据SGW发送的指示，将终端的下行数据封装于NAS消息中经由基站发送给终端，不需要建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
图9b示出了本申请实施例提供的下行数据早传方法的实现方式之十七，该实现方式之十七基于上述图3c所示的下行数据早传方法之六的描述，下面详细介绍一下该实现方式之十七。
S901b～S905b同S901a～S905a，可以参见上文中相关步骤的描述，在此不再赘述。
S906b、终端向基站发送RRC连接请求消息，用于请求建立RRC连接。基站从终端接收RRC连接请求消息。
S907b～S911b同S907a～S911a，可以参见上文中相关步骤的描述，在此不再赘述。
通过上述下行数据早传方法的实现方式之十七，MME可以根据SGW发送的指示，将终端的下行数据封装于NAS消息中经由基站发送给终端，不需要建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
图9c示出了本申请实施例提供的下行数据早传方法的实现方式之十八，该实现方式之十八基于上述图3c所示的下行数据早传方法之六的描述，下面详细介绍一下该实现方式之十八。
S901c～S905c同S901a～S905a，可以参见上文中相关步骤的描述，在此不再赘述。
S906c、终端向基站发送RRC连接请求(RRC connection request)消息，用于请求建立RRC连接。
S907c～S910c同S907a～S910a，可以参见上文中相关步骤的描述，在此不再赘述。
S911c、基站向终端发送RRC连接释放消息，终端从基站接收RRC连接释放消息。
该RRC连接释放消息(RRC connection release)中携带下行数据。具体的，基站将接收到的NAS消息封装在RRC连接释放消息中发送给终端。终端从接收到的RRC连接释放消息中获取NAS消息，从而获取下行数据。
通过上述下行数据早传方法的实现方式之十八，MME可以根据SGW发送的指示，将终端的下行数据封装于NAS消息中经由基站发送给终端，不需要建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
图10a示出了本申请实施例提供的下行数据早传方法的实现方式之十九，该实现方式之十九基于上述图3d所示的下行数据早传方法之七的描述，下面详细介绍一下该实现方式之十九。
S1001a、S-GW向MME发送下行数据通知消息(downlink data notification)，MME接收S-GW发送的下行数据通知消息。
核心网侧的S-GW有终端的下行数据到达时，会触发下行数据通知消息的发送。该下行数据通知消息中还会携带终端的标识，例如，标识为S-TMSI。
S1002a、MME接收到S-GW发送的下行数据通知消息后，向基站发送寻呼消息，基站接收MME发送的寻呼消息(即paging消息)。
该寻呼消息用于指示基站寻呼终端。该寻呼消息中会携带终端的标识，例如，标识为S-TMSI。
S1003a、基站接收到MME发送的寻呼消息后，以广播形式发送寻呼消息。
可选的，在本步骤发送的寻呼消息中也可以携带指示，该指示的含义可以参考上文中的描述。
处于idle态的终端会周期性的监听寻呼消息，当终端监听到基站发送的寻呼消息并且确认该寻呼消息中携带自己的标识时，终端触发以下步骤。
S1004a、终端向基站发送随机接入前导码(random access preamble)，基站接收终端发送的随机接入前导码。
其中，基站通过广播消息广播给所有终端若干个随机接入前导码，该终端从基站广播的若干个随机接入前导码中随机选择一个，并在基站广播的用于发送随机接入前导码的资源中随机选择一份资源，在选择的资源上发送选择的随机接入前导码。
S1005a、基站向终端发送随机接入响应(random access response,RAR)，终端接收基站发送的随机接入响应。
具体的，基站在随机接入前导码的资源上监听终端发送的随机接入前导码，当检测到某个随机接入前导码时，向终端发送RAR。其中，RAR中包含：终端发送Msg3的定时(timing advanced,TA)和终端发送Msg3的上行资源(UL grant)。
S1006a、终端向基站发送RRC数据早传请求(RRC early data request)消息，基站从终端接收RRC数据早传请求消息。
RRC数据早传请求(RRC early data request)消息，用于请求上行数据早传，该RRC数据早传请求消息中可能携带dedicated Info NAS，dedicated Info NAS本来的功能是用于承载早传的上行数据，在下行数据早传场景中，假设终端没有上行数据，则可以将dedicated Info NAS置为空NULL，用于指示未携带上行数据。
S1007a、基站向MME发送上下文恢复请求(UE context resume request)消息，MME从基站接收上下文恢复请求消息。
S1008a、MME与S-GW交互承载修改(modify bearer)消息。
S1009a、S-GW向MME发送下行数据，MME接收S-GW发送的下行数据。
该下行数据中携带指示，该指示的含义可以参考上文中的描述。
S1010a、MME将下行数据封装在NAS消息中，MME通过下行NAS传输(DL NAS transport)将下行数据发送给基站，基站从MME接收NAS消息。
该NAS消息还携带指示，该指示的含义可以参考上文中的描述。
S1011a、基站向终端发送RRC数据早传完成(RRC early data complete)消息，终端从基站接收RRC数据早传完成(RRC early data complete)消息。
该RRC数据早传完成(RRC early data complete)消息中携带下行数据。具体的，基站将接收到的NAS消息封装在RRC数据早传完成(RRC early data complete)消息中，发送给终端。终端从接收到的RRC数据早传完成(RRC early data complete)消息中获取NAS消息，从而获取下行数据。
通过上述下行数据早传方法的实现方式之十九，MME可以根据SGW发送的指示，将终端的下行数据封装于NAS消息中经由基站发送给终端，不需要建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
图10b示出了本申请实施例提供的下行数据早传方法的实现方式之二十，该实现方式之二十基于上述图3d所示的下行数据早传方法之七的描述，下面详细介绍一下该实现方式之二十。
S1001b～S1005b同S1001a～S1005a，可以参见上文中相关步骤的描述，在此不再赘述。
S1006b、终端向基站发送RRC连接请求消息，用于请求建立RRC连接。基站从终端接收RRC连接请求消息。
S1007b～S1011b同S1007a～S1011a，可以参见上文中相关步骤的描述，在此不再赘述。
通过上述下行数据早传方法的实现方式之二十，MME可以根据SGW发送的指示，将终端的下行数据封装于NAS消息中经由基站发送给终端，不需要建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
图10c示出了本申请实施例提供的下行数据早传方法的实现方式之二十一，该实现方式之二十一基于上述图3d所示的下行数据早传方法之七的描述，下面详细介绍一下该实现方式之二十一。
S1001c～S1005c同S1001a～S1005a，可以参见上文中相关步骤的描述，在此不再赘述。
S1006c、终端向基站发送RRC连接请求(RRC connection request)消息，用于请求建立RRC连接。
S1007c～S1010c同S1007a～S1010a，可以参见上文中相关步骤的描述，在此不再赘述。
S1011c、基站向终端发送RRC连接释放消息，终端从基站接收RRC连接释放消息。
该RRC连接释放消息(RRC connection release)中携带下行数据。具体的，基站将接收到的NAS消息封装在RRC连接释放消息中发送给终端。终端从接收到的RRC连接释放消息中获取NAS消息，从而获取下行数据。
通过上述下行数据早传方法的实现方式之二十一，MME可以根据SGW发送的指示，将终端的下行数据封装于NAS消息中经由基站发送给终端，不需要建立终端的RRC连接，使得终端在空闲态就可以接收完下行数据，这样有助于减少资源消耗，减少信令开销，降低终端的功耗。
基于同一种发明构思，如图11所示，本申请实施例提供了一种下行数据早传装置1100，该下行数据早传装置1100可适用于图1所示的通信系统中，执行上述方法实施例中终端的功能。为了便于说明，图11仅示出了终端的主要部件。如图11所示，终端1100包括处理器、存储器、控制电路、天线以及输入输出装置。处理器主要用于对通信协议以及通信数据进行处理，以及对整个终端进行控制，执行软件程序，处理软件程序的数据，例如用于支持终端执行上述方法实施例中所描述的动作，如，生成第一指示，向网络设备发送消息3，在消息3中携带第一指示，从网络设备接收消息4等。存储器主要用于存储软件程序和数据，例如存储上述实施例中所描述的第一指示以及下行数据等。控制电路主要用于基带信号与射频信号的转换以及对射频信号的处理。控制电路和天线一起也可以叫做收发器，主要用于收发电磁波形式的射频信号。输入输出装置，例如触摸屏、显示屏，键盘等主要用于接收用户输入的数据以及对用户输出数据。
当终端设开机后，处理器可以读取存储单元中的软件程序，解释并执行软件程序的指令，处理软件程序的数据。当需要通过无线发送数据时，处理器对待发送的数据进行基带处理后，输出基带信号至射频电路，射频电路将基带信号进行射频处理后将射频信号通过天线以电磁波的形式向外发送。当有数据发送到终端时，射频电路通过天线接收到射频信号，将射频信号转换为基带信号，并将基带信号输出至处理器，处理器将基带信号转换为数据并对该数据进行处理。
本领域技术人员可以理解，为了便于说明，图11仅示出了一个存储器和一个处理器。在实际的终端中，可以存在多个处理器和多个存储器。存储器也可以称为存储介质或者存储设备等，本申请实施例对此不做限定。
作为一种可选的实现方式，处理器可以包括基带处理器和/或中央处理器，基带处理器主要用于对通信协议以及通信数据进行处理，中央处理器主要用于对整个终端进行控制，执行软件程序，处理软件程序的数据。图11中的处理器可以集成基带处理器和中央处理器的功能，本领域技术人员可以理解，基带处理器和中央处理器也可以是各自独立的处理器，通过总线等技术互联。本领域技术人员可以理解，终端可以包括多个基带处理器以适应不同的网络制式，终端可以包括多个中央处理器以增强其处理能力，终端的各个部件可以通过各种总线连接。所述基带处理器也可以表述为基带处理电路或者基带处理芯片。所述中央处理器也可以表述为中央处理电路或者中央处理芯片。对通信协议以及通信数据进行处理的功能可以内置在处理器中，也可以以软件程序的形式存储在存储单元中，由处理器执行软件程序以实现基带处理功能。
在本申请实施例中，可以将具有收发功能的天线和控制电路视为终端1100的收发单元1101，例如，用于支持终端执行如上述方法实施例所述的接收功能和发送功能。将具有处 理功能的处理器视为终端设备1100的处理单元1102。如图11所示，终端1100包括收发单元1101和处理单元1102。收发单元也可以称为收发器、收发机、收发装置等。可选的，可以将收发单元1101中用于实现接收功能的器件视为接收单元，将收发单元1101中用于实现发送功能的器件视为发送单元，即收发单元1101包括接收单元和发送单元，接收单元也可以称为接收机、输入口、接收电路等，发送单元可以称为发射机、发射器或者发射电路等。
处理器1102可用于执行该存储器存储的指令，以控制收发单元1101接收信号和/或发送信号，完成上述方法实施例中终端的功能。作为一种实现方式，收发单元1101的功能可以考虑通过收发电路或者收发的专用芯片实现。
图12是本申请实施例提供的一种下行数据早传装置的结构示意图，如可以为接入网设备(即基站)的结构示意图。如图12所示，该接入网设备可应用于如图1所示的系统中，执行上述方法实施例中第一网络设备的功能。网络设备1200(也可以称作基站1200)可包括一个或多个射频单元，如远端射频单元(remote radio unit,RRU)1201和一个或多个基带单元(baseband unit，BBU)(也可称为数字单元，digital unit，DU)1202。所述RRU 1201可以称为收发单元、收发机、收发电路、或者收发器等等，其可以包括至少一个天线12011和射频单元12012。所述RRU 1201部分主要用于射频信号的收发以及射频信号与基带信号的转换，例如用于接收终端发送的指示，或接收第二网络设备发送的指示，或向终端发送下行数据。所述BBU 1202部分主要用于进行基带处理，对基站进行控制等。所述RRU 1201与BBU 1202可以是物理上设置在一起，也可以物理上分离设置的，即分布式基站。
所述BBU 1202为基站的控制中心，也可以称为处理单元，主要用于完成基带处理功能，如信道编码，复用，调制，扩频等等。例如所述BBU(处理单元)1202可以用于控制基站执行上述方法实施例中关于第一网络设备的操作流程。
在一个实例中，所述BBU 1202可以由一个或多个单板构成，多个单板可以共同支持单一接入指示的无线接入网(如LTE网)，也可以分别支持不同接入制式的无线接入网(如LTE网，12G网或其他网)。所述BBU 1202还包括存储器12021和处理器12022，所述存储器12021用于存储必要的指令和数据。例如存储器12021存储上述实施例中的码本索引与预编码矩阵的对应关系。所述处理器12022用于控制基站进行必要的动作，例如用于控制基站执行上述方法实施例中关于第一网络设备的操作流程。所述存储器12021和处理器12022可以服务于一个或多个单板。也就是说，可以每个单板上单独设置存储器和处理器。也可以是多个单板共用相同的存储器和处理器。此外每个单板上还可以设置有必要的电路。
基于与上述方法实施例的同一发明构思，如图13所示，本申请实施例还提供了一种下行数据早传装置1300，该下行数据早传装置1300用于实现上述实施例中第二网络设备(即第一核心网设备)和第三网络设备(即第二核心网设备)执行的操作，为简述示意，上述第一核心网设备和第二核心网设备可能的装置的示意图通过引用图13来示意，可以理解的是，图13仅为示意图，其可以应用于上述第一核心网设备和第二核心网设备中。该下行数据早传装置1300包括：收发器1301、处理器1302、存储器1303。处理器1302用于调用一组程序，当程序被执行时，使得处理器1302执行上述实施例提供的通信方法之一中第二网络设备和第三网络设备执行的操作。存储器1303用于存储处理器1302执行 的程序。收发器1301可以视为第二网络设备/第三网络设备的收发单元，用于支持第二网络设备/第三网络设备执行上述方法实施例所述的接收功能和发送功能。处理器1302可以视为第二网络设备/第三网络设备的处理单元。可选的，可以将收发单元中应用于实现接收功能的器件视为接收单元，将收发单元用于实现发送功能的器件视为发送单元，即收发单元包括接收单元和发送单元，接收单元也可以称为接收机、输入口、接收电路等，发送单元可以称为发射机、发射器或者发射电路等。
本申请还提供一种通信系统，其包括前述的一个或多个网络设备，和，一个或多个终端。
应注意，本申请实施例中的处理器可以是一种集成电路芯片，具有信号的处理能力。在实现过程中，上述方法实施例的各步骤可以通过处理器中的硬件的集成逻辑电路或者软件形式的指令完成。上述的处理器可以是通用处理器、数字信号处理器(digital signal processor，DSP)、专用集成电路(application specific integrated circuit，ASIC)、现成可编程门阵列(field programmable gate array，FPGA)或者其他可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件。可以实现或者执行本申请实施例中的公开的各方法、步骤及逻辑框图。通用处理器可以是微处理器或者该处理器也可以是任何常规的处理器等。结合本申请实施例所公开的方法的步骤可以直接体现为硬件译码处理器执行完成，或者用译码处理器中的硬件及软件模块组合执行完成。软件模块可以位于随机存储器，闪存、只读存储器，可编程只读存储器或者电可擦写可编程存储器、寄存器等本领域成熟的存储介质中。该存储介质位于存储器，处理器读取存储器中的信息，结合其硬件完成上述方法的步骤。
可以理解，本申请实施例中的存储器可以是易失性存储器或非易失性存储器，或可包括易失性和非易失性存储器两者。其中，非易失性存储器可以是只读存储器(read-only memory，ROM)、可编程只读存储器(programmable ROM，PROM)、可擦除可编程只读存储器(erasable PROM，EPROM)、电可擦除可编程只读存储器(electrically EPROM，EEPROM)或闪存。易失性存储器可以是随机存取存储器(random access memory，RAM)，其用作外部高速缓存。通过示例性但不是限制性说明，许多形式的RAM可用，例如静态随机存取存储器(static RAM，SRAM)、动态随机存取存储器(dynamic RAM，DRAM)、同步动态随机存取存储器(synchronous DRAM，SDRAM)、双倍数据速率同步动态随机存取存储器(double data rate SDRAM，DDR SDRAM)、增强型同步动态随机存取存储器(enhanced SDRAM，ESDRAM)、同步连接动态随机存取存储器(synchlink DRAM，SLDRAM)和直接内存总线随机存取存储器(direct rambus RAM，DR RAM)。应注意，本文描述的系统和方法的存储器旨在包括但不限于这些和任意其它适合类型的存储器。
本申请实施例还提供了一种计算机可读介质，其上存储有计算机程序，该计算机程序被计算机执行时实现上述任一方法实施例所述的方法。
本申请实施例还提供了一种计算机程序产品，该计算机程序产品被计算机执行时实现上述任一方法实施例所述的方法。
在上述实施例中，可以全部或部分地通过软件、硬件、固件或者其任意组合来实现。当使用软件实现时，可以全部或部分地以计算机程序产品的形式实现。所述计算机程序产品包括一个或多个计算机指令。在计算机上加载和执行所述计算机指令时，全部或部分地产生按照本申请实施例所述的流程或功能。所述计算机可以是通用计算机、专用计算机、 计算机网络、或者其他可编程装置。所述计算机指令可以存储在计算机可读存储介质中，或者从一个计算机可读存储介质向另一个计算机可读存储介质传输，例如，所述计算机指令可以从一个网站站点、计算机、服务器或数据中心通过有线(例如同轴电缆、光纤、数字用户线(Digital Subscriber Line，DSL))或无线(例如红外、无线、微波等)方式向另一个网站站点、计算机、服务器或数据中心进行传输。所述计算机可读存储介质可以是计算机能够存取的任何可用介质或者是包含一个或多个可用介质集成的服务器、数据中心等数据存储设备。所述可用介质可以是磁性介质(例如，软盘、硬盘、磁带)、光介质(例如，高密度数字视频光盘(Digital Video Disc，DVD))、或者半导体介质(例如，固态硬盘(Solid State Disk，SSD))等。
本申请实施例还提供了一种处理装置，包括处理器和接口；所述处理器，用于执行上述任一方法实施例所述的通信方法。
应理解，上述处理装置可以是一个芯片，所述处理器可以通过硬件来实现也可以通过软件来实现，当通过硬件实现时，该处理器可以是逻辑电路、集成电路等；当通过软件来实现时，该处理器可以是一个通用处理器，通过读取存储器中存储的软件代码来实现，改存储器可以集成在处理器中，可以位于所述处理器之外，独立存在。
应理解，说明书通篇中提到的“一个实施例”或“一实施例”意味着与实施例有关的特定特征、结构或特性包括在本申请的至少一个实施例中。因此，在整个说明书各处出现的“在一个实施例中”或“在一实施例中”未必一定指相同的实施例。此外，这些特定的特征、结构或特性可以任意适合的方式结合在一个或多个实施例中。应理解，在本申请的各种实施例中，上述各过程的序号的大小并不意味着执行顺序的先后，各过程的执行顺序应以其功能和内在逻辑确定，而不应对本申请实施例的实施过程构成任何限定。
本领域内的技术人员应明白，本申请的实施例可提供为方法、系统、或计算机程序产品。因此，本申请可采用完全硬件实施例、完全软件实施例、或结合软件和硬件方面的实施例的形式。而且，本申请可采用在一个或多个其中包含有计算机可用程序代码的计算机可用存储介质(包括但不限于磁盘存储器、CD-ROM、光学存储器等)上实施的计算机程序产品的形式。
本申请是参照根据本申请实施例的方法、设备(系统)、和计算机程序产品的流程图和/或方框图来描述的。应理解可由计算机程序指令实现流程图和/或方框图中的每一流程和/或方框、以及流程图和/或方框图中的流程和/或方框的结合。可提供这些计算机程序指令到通用计算机、专用计算机、嵌入式处理机或其他可编程数据处理设备的处理器以产生一个机器，使得通过计算机或其他可编程数据处理设备的处理器执行的指令产生用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的装置。
这些计算机程序指令也可存储在能引导计算机或其他可编程数据处理设备以特定方式工作的计算机可读存储器中，使得存储在该计算机可读存储器中的指令产生包括指令装置的制造品，该指令装置实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能。
这些计算机程序指令也可装载到计算机或其他可编程数据处理设备上，使得在计算机或其他可编程设备上执行一系列操作步骤以产生计算机实现的处理，从而在计算机或其他可编程设备上执行的指令提供用于实现在流程图一个流程或多个流程和/或方框图一个 方框或多个方框中指定的功能的步骤。
尽管已描述了本申请的优选实施例，但本领域内的技术人员一旦得知了基本创造性概念，则可对这些实施例作出另外的变更和修改。所以，所附权利要求意欲解释为包括优选实施例以及落入本申请范围的所有变更和修改。
显然，本领域的技术人员可以对本申请实施例进行各种改动和变型而不脱离本申请实施例的精神和范围。这样，倘若本申请实施例的这些修改和变型属于本申请权利要求及其等同技术的范围之内，则本申请也意图包含这些改动和变型在内。

Claims (25)

  1. 一种下行数据早传方法，其特征在于，包括：
    向网络设备发送随机接入前导码；
    从所述网络设备接收随机接入响应；
    响应于所述随机接入响应，向所述网络设备发送消息3，所述消息3携带第一指示，所述第一指示用于指示单个下行数据包；
    从所述网络设备接收消息4，所述消息4携带下行数据。
  2. 如权利要求1所述的方法，其特征在于，所述消息3为用于请求恢复RRC连接的第一RRC消息。
  3. 如权利要求1或2所述的方法，其特征在于，所述消息4为用于指示释放所述RRC连接的第二RRC消息。
  4. 如权利要求1～3任一项所述的方法，其特征在于，所述方法还包括：
    恢复上下文信息，所述上下文信息包括第一下一跳链计数NCC，所述第一NCC用于推演第一密钥；
    使用所述第一密钥对所述下行数据进行解密。
  5. 如权利要求4所述的方法，其特征在于，所述方法还包括：
    所述上下文信息还包括第三密钥，使用所述第三密钥对所述消息4进行完整性保护校验；或者，
    使用所述第一NCC推演第二密钥，使用所述第二密钥对所述消息4进行完整性保护校验；或者，
    使用所述第一NCC推演第二密钥和第四密钥，使用所述第二密钥对所述消息4进行完整性保护校验，使用所述第四密钥对所述消息4进行解密。
  6. 如权利要求1～3任一项所述的方法，其特征在于，所述消息4携带第二NCC；
    所述方法还包括：
    使用所述第二NCC推演第五密钥；
    使用所述第五密钥对所述下行数据进行解密。
  7. 如权利要求6所述的方法，其特征在于，所述方法还包括：
    使用所述第二NCC推演第六密钥，使用所述第六密钥对所述消息4进行完整性保护校验；或者，
    恢复上下文信息，所述上下文信息包括第三密钥，使用所述第三密钥对所述消息4进行完整性保护校验。
  8. 如权利要求1～7任一种所述的方法，其特征在于，所述方法还包括：
    从所述网络设备接收第二指示，所述第二指示用于指示单个下行数据包。
  9. 如权利要求1～8任一种所述的方法，其特征在于，所述方法还包括：
    从所述网络设备接收准许指示，所述准许指示用于指示所述网络设备准许下行数据早传。
  10. 一种下行数据早传方法，其特征在于，包括：
    第一网络设备从终端接收随机接入前导码；
    所述第一网络设备向所述终端发送随机接入响应；
    所述第一网络设备从所述终端接收消息3，所述消息3携带第一指示，所述第一指示用于指示所述单个下行数据包；
    所述第一网络设备向所述终端发送消息4，所述消息4携带下行数据。
  11. 一种下行数据早传方法，其特征在于，包括：
    第一网络设备从第二网络设备接收寻呼消息，所述寻呼消息中携带第一指示，所述第一指示用于指示单个下行数据包；
    所述第一网络设备从终端接收随机接入前导码；
    所述第一网络设备向所述终端发送随机接入响应；
    所述第一网络设备从所述终端接收消息3；
    所述第一网络设备向所述终端发送消息4，所述消息4为RRC消息，所述RRC消息中包含所述终端的下行数据。
  12. 如权利要求10或11所述的方法，其特征在于，所述消息3为用于请求恢复RRC连接的第一RRC消息。
  13. 如权利要求10～12任一项所述的方法，其特征在于，所述消息4为用于指示释放所述RRC连接的第二RRC消息。
  14. 如权利要求10～13任一项所述的方法，其特征在于，所述方法还包括：
    所述第一网络设备恢复所述终端的上下文信息，所述上下文信息包括第一下一跳链计数NCC，所述第一NCC用于推演第一密钥；
    所述第一网络设备使用所述第一密钥对所述下行数据进行加密。
  15. 如权利要求14所述的方法，其特征在于，所述方法还包括：
    所述上下文信息还包括第三密钥，所述第一网络设备使用所述第三密钥对所述消息4进行完整性保护；或者，
    所述第一网络设备使用所述第一NCC推演第二密钥，所述第一网络设备使用所述第二密钥对消息4进行完整性保护；或者，
    所述第一网络设备使用所述第一NCC推演第二密钥和第四密钥，使用所述第二密钥对所述消息4进行完整性保护，使用所述第四密钥对所述消息4进行加密。
  16. 如权利要求10～13任一项所述的方法，其特征在于，所述消息4携带第二NCC，所述方法还包括：
    所述第一网络设备使用所述第二NCC推演第五密钥，使用所述第五密钥对所述下行数据进行加密。
  17. 如权利要求16所述的方法，其特征在于，所述方法还包括：
    所述第一网络设备使用所述第二NCC推演第六密钥，使用所述第六密钥对所述消息4进行完整性保护；或者，
    所述第一网络设备恢复所述终端的上下文信息，所述上下文信息包括第三密钥，使用所述第三密钥对所述消息4进行完整性保护。
  18. 如权利要求10～17任一项所述的方法，其特征在于，所述方法还包括：
    所述第一网络设备向所述终端发送第二指示，所述第二指示用于指示单个下行数据包。
  19. 如权利要求10、12～18任一项所述的方法，其特征在于，所述方法还包括：
    所述第一网络设备从第二网络设备接收第三指示，所述第三指示用于指示单个下行数 据包。
  20. 如权利要求10～18任一项所述的方法，其特征在于，所述方法还包括：
    所述第一网络设备从第三网络设备接收下行数据，所述下行数据携带第四指示，所述第四指示消息用于指示单个下行数据包。
  21. 一种下行数据传输装置，其特征在于，包括：
    处理器，用于与存储器耦合，调用所述存储器中的程序，执行所述程序以实现如权利要求1-9任意一项所述的方法。
  22. 一种下行数据传输装置，其特征在于，包括：
    处理器，用于与存储器耦合，调用所述存储器中的程序，执行所述程序以实现如权利要求10-20任意一项所述的方法。
  23. 一种计算机可读存储介质，其特征在于，所述计算机存储介质中存储有计算机可读指令，当计算机读取并执行所述计算机可读指令时，使得计算机执行如权利要求1-20任意一项所述的方法。
  24. 一种计算机程序产品，其特征在于，当计算机读取并执行所述计算机程序产品时，使得计算机执行如权利要求1-20任意一项所述的方法。
  25. 一种芯片，其特征在于，所述芯片与存储器相连或者所述芯片包括所述存储器，用于读取并执行所述存储器中存储的软件程序，以实现如权利要求1-20任意一项所述的方法。
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US20210195424A1 (en) 2021-06-24
EP3846577A4 (en) 2021-08-18

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