Data transmission system, method, and apparatus

Abstract

The present invention discloses a data transmission system. The first device performs, at a cellular network PDCP layer of the first device, security processing on to-be-transmitted data based on a transmit end-based first policy, to generate a PDU, and sends the PDU to the relay UE, where the first policy is a security processing policy agreed on by the first device and the second device, and the to-be-transmitted data is data that the first device needs to transmit to the second device. The relay UE sends the PDU to the second device. The second device performs, at a cellular network PDCP layer of the second device, security processing on the PDU based on a receive end-based first policy, to obtain the to-be-transmitted data, where the cellular network PDCP layer of the first device is a peer to the cellular network PDCP layer of the second device.

What is claimed is: 
     
         1 . A data transmission system, comprising: a first device, relay user equipment (UE), and a second device, wherein:
 the first device performs, at a cellular network Packet Data Convergence Protocol (PDCP) layer of the first device, security processing on to-be-transmitted data based on a transmit end-based first policy, to generate a protocol data unit (PDU), and sends the PDU to the relay UE, wherein the first policy is a security processing policy agreed upon by the first device and the second device, and the to-be-transmitted data is data that the first device needs to transmit to the second device;   the relay UE receives the PDU from the first device, and sends the PDU to the second device; and   the second device receives the PDU from the relay UE, and performs, at a cellular network PDCP layer of the second device, security processing on the PDU based on a receive end-based first policy, to obtain the to-be-transmitted data; wherein the cellular network PDCP layer of the first device is a peer to the cellular network PDCP layer of the second device.   
     
     
         2 . The system according to  claim 1 , wherein that the first device sends the PDU to the relay UE comprises:
 the first device sends the PDU to the relay UE successively through the cellular network PDCP layer of the first device and a protocol module of a first interface of the first device;   wherein that the relay UE sends the PDU to the second device comprises:   the relay UE sends the PDU to the second device successively through a protocol module of a first interface of the relay UE and a protocol module of a second interface of the relay UE; and   wherein that the second device receives the PDU from the relay UE, and performs, at a cellular network PDCP layer of the second device, security processing on the PDU based on the receive end-based first policy, to obtain the to-be-transmitted data comprises:   the second device receives the PDU from the relay UE, transmits the PDU to the cellular network PDCP layer of the second device through a protocol module of a second interface of the second device, and performs, at the cellular network PDCP layer of the second device, security processing on the PDU based on the receive end-based first policy, to obtain the to-be-transmitted data; wherein   the protocol module of the first interface of the relay UE is a peer to the protocol module of the first interface of the first device, the protocol module of the second interface of the relay UE is a peer to the protocol module of the second interface of the second device, the first interface is a communications interface between the first device and the relay UE, and the second interface is a communications interface between the relay UE and the second device.   
     
     
         3 . The system according to  claim 1 , further comprising:
 a base station to send a first instruction message to each of far-end UE, wherein the first instruction message is used to instruct a receiver to establish a first PDCP layer; and   far-end UE to receive the first instruction message from the base station, and establishing the first PDCP layer on the far-end UE based on the first instruction message.   
     
     
         4 . The system according to  claim 2 , wherein a protocol module of an interface between a far-end UE and a base station comprises a second PDCP layer, used to perform security processing on data based on a third policy agreed upon by the relay UE and the base station;
 the base station establishes the second PDCP layer, and sends a second instruction message to the relay UE, wherein the second instruction message is used to instruct the relay UE to establish the second PDCP layer; and   the relay UE receives the second instruction message from the base station, and establishes the second PDCP layer on the relay UE based on the second instruction message.   
     
     
         5 . A data transmission method, comprising:
 performing, by a first device at a cellular network Packet Data Convergence Protocol (PDCP) layer of the first device, security processing on to-be-transmitted data based on a transmit end-based first policy, to generate a protocol data unit (PDU), wherein the first policy is a security processing policy agreed upon by the first device and a second device, and the to-be-transmitted data is data that the first device needs to transmit to the second device; and   sending, by the first device, the PDU to the second device through relay user equipment (UE), wherein the second device comprises a cellular network PDCP layer that is a peer to the cellular network PDCP layer of the first device; wherein   the first device is far-end UE, and the second device is a base station; or the first device is a base station, and the second device is far-end UE.   
     
     
         6 . The method according to  claim 5 , further comprising:
 receiving, by the far-end UE, a first instruction message from the base station, wherein the first instruction message is used to instruct the far-end UE to establish the first PDCP layer; and   establishing, by the far-end UE, the first PDCP layer based on the first instruction message.   
     
     
         7 . The method according to  claim 5 , further comprising:
 sending, by the base station, a first instruction message to each of far-end UE, wherein the first instruction message is used to instruct a receiver to establish the first PDCP layer.   
     
     
         8 . The method according to  claim 7 , wherein a protocol module of an interface between the relay UE and the base station comprises a second PDCP layer, used to perform security processing on data based on a third policy agreed upon by the relay UE and the base station, the first device is the base station, and the method further comprises:
 establishing, by the base station, the second PDCP layer; and   sending, by the base station, a second instruction message to the relay UE, wherein the second instruction message is used to instruct the relay UE to establish the second PDCP layer.   
     
     
         9 . A data transmission method, comprising:
 receiving, by relay user equipment (UE), a protocol data unit (PDU) from a first device, wherein the PDU is a PDU generated after the first device performs, at a cellular network Packet Data Convergence Protocol (PDCP) layer of the first device, security processing on to-be-transmitted data based on a transmit end-based first policy, wherein the first policy is a security processing policy agreed upon by the first device and a second device, and the to-be-transmitted data is data that the first device needs to transmit to the second device; and   sending, by the relay UE, the PDU to the second device, wherein the second device comprises a cellular network PDCP layer that is a peer to the cellular network PDCP layer of the first device.   
     
     
         10 . The method according to  claim 9 , wherein the sending, by the relay UE, the PDU to the second device comprises:
 sending, by the relay UE, the PDU to the second device successively through a protocol module of a first interface of the relay UE and a protocol module of a second interface of the relay UE, wherein the first interface is a communications interface between the first device and the relay UE, and the second interface is a communications interface between the relay UE and the second device.   
     
     
         11 . The method according to  claim 9 , wherein a protocol module of an interface between the relay UE and the base station comprises a second PDCP layer, used to perform security processing on data based on a third policy agreed on by the relay UE and the base station, and the method further comprises:
 receiving, by the relay UE, a second instruction message from the base station, wherein the second instruction message is used to instruct the relay UE to establish the second PDCP layer; and   establishing, by the relay UE, the second PDCP layer based on the second instruction message.   
     
     
         12 . The method according to  claim 9 , further comprising:
 receiving, by the relay UE, a radio resource control (RRC) message from the first device, wherein the RRC message is generated by the first device at an RRC layer of the first device; and   sending, by the relay UE, the RRC message to the second device, wherein the second device comprises an RRC layer that is a peer to the RRC layer of the first device.   
     
     
         13 . A data transmission method, comprising:
 receiving, by a second device, a protocol data unit (PDU) from a first device and forwarded by relay user equipment (UE), wherein the PDU is generated after the first device performs, at a cellular network Packet Data Convergence Protocol (PDCP) layer of the first device, security processing on to-be-transmitted data based on a transmit end-based first policy, wherein the first policy is a security processing policy agreed upon by the first device and the second device, and the to-be-transmitted data is data that the first device needs to transmit to the second device; and   performing, by the second device at a cellular network PDCP layer of the second device, security processing on the PDU based on a receive end-based first policy, to obtain the to-be-transmitted data; wherein   the cellular network PDCP layer of the first device is a peer to the cellular network PDCP layer of the second device; and the first device is far-end UE, and the second device is a base station; or the first device is a base station, and the second device is far-end UE.   
     
     
         14 . The method according to  claim 13 , after the receiving, by the second device, a PDU that is forwarded by relay UE, further comprising:
 transmitting, by the second device, the PDU to the cellular network PDCP layer of the second device successively through a protocol module of a second interface of the second device, wherein the second interface is a communications interface between the relay UE and the second device.   
     
     
         15 . The method according to  claim 13 , further comprising:
 receiving, by the second device, a radio resource control (RRC) message from the first device and forwarded by the relay UE; and   transmitting the RRC message to an RRC layer of the second device, wherein the RRC layer of the second device is set at an upper layer of the cellular network PDCP layer of the second device, and the first device comprises an RRC layer that is a peer to the RRC layer of the second device.   
     
     
         16 . A first communication apparatus, comprising:
 a processor, configured to perform, at a cellular network Packet Data Convergence Protocol (PDCP) layer of the apparatus, security processing on to-be-transmitted data based on a transmit end-based first policy, to generate a protocol data unit (PDU), wherein the first policy is a security processing policy agreed upon by the apparatus and a second device, and the to-be-transmitted data is data that the apparatus needs to transmit to the second device; and   a transmitter, configured to send the PDU to the second device through relay user equipment (UE), wherein the second device comprises a cellular network PDCP layer that is a peer to the cellular network PDCP layer of the apparatus.   
     
     
         17 . The apparatus according to  claim 16 , further comprising:
 a transmitter configured to send the PDU to the relay UE successively through the cellular network PDCP layer of the apparatus and a protocol module of a first interface of the apparatus, wherein the first interface is a communications interface between the apparatus and the relay UE.   
     
     
         18 . The apparatus according to  claim 16 , further comprising:
 a receiver, configured to receive a first instruction message, wherein the first instruction message is used to instruct far-end UE to establish the first PDCP layer; and   the processor is further configured to establish the first PDCP layer based on the first instruction message.   
     
     
         19 . A communication device, comprising:
 a receiver, configured to receive a protocol data unit (PDU) from a first device, wherein the PDU generated after the first device performs, at a cellular network Packet Data Convergence Protocol (PDCP) layer of the first device, security processing on to-be-transmitted data based on a transmit end-based first policy, the first policy is a security processing policy agreed upon by the first device and a second device, and the to-be-transmitted data is data that the first device needs to transmit to the second device; and   a transmitter, configured to send the PDU to the second device, wherein the second device comprises a cellular network PDCP layer that is a peer to the cellular network PDCP layer of the first device.   
     
     
         20 . The communication device according to  claim 19 , wherein:
 the transmitter is configured to send the PDU to the second device successively through a protocol module of a first interface of the communication device and a protocol module of a second interface of the communication device, wherein the first interface is a communications interface between the first device and the communication device, and the second interface is a communications interface between the communication device and the second device.