WO2022056746A1

WO2022056746A1 - Communication method and communication apparatus

Info

Publication number: WO2022056746A1
Application number: PCT/CN2020/115696
Authority: WO
Inventors: 许斌; 李秉肇; 曹振臻
Original assignee: 华为技术有限公司
Priority date: 2020-09-16
Filing date: 2020-09-16
Publication date: 2022-03-24

Abstract

The present application provides a communication method and a communication apparatus, which are applied to the technical field of wireless communications. The method comprises: a radio link control entity receives a first data packet, the first data packet being transmitted by means of a first transmission mode; when the first transmission model is switched to a second transmission mode, update parameters of a receiving window of the radio link control entity, the receiving window being used for reassembling a service data unit (SDU) segment, and the first transmission mode and the second transmission mode are one and the other of a point-to-multipoint transmission mode and a point-to-point transmission mode; when a terminal device determines that the transmission mode of a data packet sent by a network device has been switched, update the parameters of the receiving window of the radio link control entity of the terminal device. Updating the parameters of the receiving window can avoid the occurrence of data merging errors or packet loss.

Description

A communication method and communication device

technical field

The present application relates to the field of communication technologies, and in particular, to a communication method and a communication device.

Background technique

Multicast broadcast service (Multicast and Broadcast Service, MBS) is a service for multiple terminal equipment (User Equipment, UE), such as live broadcast service, public safety service, batch software update service, etc.

The MBS service comes from the data server. First, the data server sends the MBS data to the core network device, then the core network device sends the MBS data to the access network device, and finally the access network device sends the MBS data to at least one terminal device that receives the MBS service. . The access network equipment can send the MBS service to the terminal equipment in various transmission modes. How to realize the switching between different transmission modes and data processing and maintain the reliability of the service transmission is a problem that needs to be solved.

SUMMARY OF THE INVENTION

The present application provides a communication method and a communication device, which can realize switching between different transmission modes and data processing, and improve the reliability of service transmission.

In a first aspect, a communication method is provided, including: a radio link control entity of a terminal device receives a first data packet sent by a network device, and the first data packet is transmitted in a first transmission mode. When the network device switches the first transmission mode to the second transmission mode, the terminal device updates the parameters of the reception window of the RLC entity, and the reception window is used to reassemble the SDU segment of the service data unit. The parameters of the receiving window include: one or more of a reassembly timer, a receiving state variable, and a receiving window size. The receiving state variable may include the earliest SN (RX_Next_Reassembly) of the SNs waiting for reassembly, the next SN of the SN that triggers the reassembly timer (RX_Timer_Trigger), and the next SN of the largest SN of all received SNs (RX_Next_Highest) one or more of. The radio link control entity receives a second data packet, the second data packet is transmitted through a second transmission mode, and the first transmission mode and the second transmission mode are one of a point-to-multipoint transmission mode and a point-to-point transmission mode and another.

In the embodiment of the present application, the terminal device has a protocol stack architecture of a single RLC entity, and the single RLC entity receives data packets in point-to-point and point-to-multipoint transmission modes, thereby reducing the complexity of the terminal device. The network device sends the first data packet in the first transmission mode, then switches the transmission mode to the second transmission mode, and sends the second data packet in the second transmission mode. When the transmission mode is switched, the terminal device updates the RLC entity's reception parameters of the window, so as to ensure the continuity of service transmission.

In a possible implementation manner of the first aspect, the terminal device receives first indication information sent by the network device, where the first indication information is used to instruct the first transmission mode to switch to the second transmission mode. The terminal device judges that the transmission mode is switched from the first transmission mode to the second transmission mode according to the first indication information, and updates the parameters of the receiving window of the RLC entity.

In the embodiment of the present application, the network device sends the first indication information to the terminal device to indicate that the transmission mode is switched, and the terminal device can update the parameters of the receiving window in time according to the indication information.

In a possible implementation manner of the first aspect, the first indication information may specifically indicate the first transmission mode and/or the second transmission mode, or the first indication information indicates that the transmission mode is switched.

In this embodiment of the present application, when the first indication information indicates the first transmission mode and/or the second transmission mode, the terminal device can know, according to the first indication information, whether the switched transmission mode is the point-to-point transmission mode or the point-to-multipoint transmission mode Which of the transfer modes. When the first indication information indicates that the transmission mode is switched, the terminal device can know that the transmission mode is switched, and the terminal device further determines whether the switched transmission mode is the point-to-point transmission mode or the point-to-point transmission mode according to the second data packet received after the transmission mode is switched. Multipoint transmission mode.

In a possible implementation manner of the first aspect, the terminal device determines, according to the second data packet, that the transmission mode is switched from the first transmission mode to the second transmission mode.

In this embodiment of the present application, when the terminal device receives the second data packet, it can learn which transmission mode the network device transmits. At this time, the terminal device may compare the transmission mode of the currently received second data packet with the transmission mode of the last received data packet, so as to determine whether the transmission mode has been switched.

In a possible implementation manner of the first aspect, the first transmission mode is a point-to-multipoint transmission mode, and the second transmission mode is a point-to-point transmission mode. The updating of the parameters of the receiving window of the radio link control entity by the terminal device includes: updating the parameters of the receiving window as an initial value, and the initial value may be specified by a protocol.

In the embodiment of the present application, when the network device switches from the first transmission mode to the second transmission mode, the terminal device updates the parameters of the receiving window of the RLC entity to the initial value, and the update to the initial value compares the implementation requirements of the terminal device It is simple, and since the terminal device has the same understanding of the SN allocation method adopted when the terminal device receives the data packet and the network device transmits it, it can prevent data packet loss or data merging errors after switching the transmission mode.

In a possible implementation manner of the first aspect, the first transmission mode is a point-to-multipoint transmission mode, and the second transmission mode is a point-to-point transmission mode. Updating the parameter of the receiving window of the RLC entity includes: updating the parameter of the receiving window as a first parameter, and the first parameter is the parameter of the receiving window in the last point-to-point transmission mode. The first parameter may be a parameter of the receiving window of the terminal device when the terminal device receives the last service data unit or service data unit segment transmitted in the last point-to-point transmission mode.

In the embodiment of the present application, when the network device switches from the first transmission mode to the second transmission mode, the terminal device updates the parameters of the receiving window of the RLC entity to the parameters of the receiving window in the last point-to-point transmission mode, This allows the terminal device to continue to receive data packets following the last stored receiving state, without the need for the terminal device to perform additional actions, and because the terminal device has the same understanding of the SN allocation method used when the terminal device receives the data packet and the network device sends it, it can prevent Packet loss or data merging error after switching transmission modes.

In a possible implementation manner of the first aspect, the first transmission mode is a point-to-point transmission mode, and the second transmission mode is a point-to-multipoint transmission mode. The terminal device receives the second indication information sent by the network device, where the second indication information is used to indicate the serial number SN. The terminal equipment updating the parameters of the receiving window of the RLC entity includes: updating the parameters of the receiving window according to the SN.

In this embodiment of the present application, when the network device switches from the first transmission mode to the second transmission mode, the terminal device receives the second indication information sent by the network device, and the second indication information indicates the value of the SN. The terminal device may update the parameters of the receiving window according to the value of the SN indicated by the second indication information. Packet loss or data merging errors after switching transmission modes can be prevented.

In a possible implementation manner of the first aspect, the second data packet includes a service data unit SDU segment. Updating the parameters of the receiving window of the RLC entity includes: updating the parameters of the receiving window according to the sequence number SN, where the sequence number SN is the first SDU segment received by the terminal device in the second transmission mode.

In this embodiment of the present application, when the network device switches from the first transmission mode to the second transmission mode, the terminal device receives the SDU segment sent by the network device, and the terminal device can receive the SDU segment according to the first SDU segment received in the second transmission mode. Update the parameters of the receive window, thereby preventing packet loss or data merging errors after switching transmission modes.

In a possible implementation manner of the first aspect, the first data packet includes a SDU segment, and when switching from the first transmission mode to the second transmission mode, the terminal device discards the receiving window and receives in the first transmission mode SDU segment.

In a second aspect, a communication method is provided, including: a radio link control entity of a network device sends a first data packet in a first transmission mode. Switching from the first transmission mode to the second transmission mode, the network device determines the SN of the second data packet. The second data packet may include a service data unit SDU segment, the second data packet includes a packet header, and the packet header includes an SN number of the SDU segment. After receiving the second data packet, the RLC of the terminal device can reassemble the SDU segments according to the SN number in the packet header to assemble a complete SDU, and the RLC of the terminal device sends the assembled complete SDU to the PDCP. The radio link control entity of the network device sends the second data packet in the second transmission mode. The first transmission mode and the second transmission mode are one and the other of a point-to-multipoint transmission mode and a point-to-point transmission mode. The SN number of the second data packet may refer to the SN number allocated to the second data packet by the RLC of the network device. It can also be understood that the network device determines the SN of the second data packet as the network device updates the SN number of the second data packet.

In this embodiment of the present application, the network device switches the transmission mode from the first transmission mode to the second transmission mode, and the network device determines the SN number of the second data packet. By updating the SN number of the second data packet, the situation of data packet transmission loss or data merging errors can be avoided.

In a possible implementation manner of the second aspect, the first transmission mode is a point-to-multipoint transmission mode, the second transmission mode is a point-to-point transmission mode, and SN is an initial value. The initial value can be specified by the protocol, for example, the initial value is 1.

In this embodiment of the present application, after the transmission mode is switched, the SN number of the SDU segment of the second data packet may be updated to an initial value. By updating the SN number of the second data packet, the situation of data packet transmission loss or data merging errors can be avoided.

In a possible implementation manner of the second aspect, the first transmission mode is a point-to-multipoint transmission mode, and the second transmission mode is a point-to-point transmission mode. The network device determining the SN of the second data packet includes: the network device determining the SN according to the first SN, where the first SN is the maximum SN corresponding to the SDU segment transmitted in the last point-to-point transmission mode. The maximum SN refers to the SN with the largest value among the SNs corresponding to the SDU segment transmitted in the last point-to-point transmission mode. The network device may update the SN of the second data packet to the first SN+1. For example, when the first SN is 7, the network device may update the SN of the second data packet to 8.

In the embodiment of the present application, after the transmission mode is switched, the SN number of the SDU segment of the second data packet may be updated to the maximum SN corresponding to the SDU segment transmitted in the last point-to-point transmission mode. By updating the SN number of the second data packet, the situation of data packet transmission loss or data merging errors can be avoided.

In a possible implementation manner of the second aspect, the first data packet includes a service data unit SDU segment. A complete SDU corresponding to the first SDU segment is sent in the second transmission mode, and the first SDU segment is at least one of the SDU segments sent in the first transmission mode. The complete SDU corresponding to the first SDU segment is sent in the second transmission mode, the complete SDU may be sent directly, or all the first SDU segments corresponding to the complete SDU may be segmented in the second sent in transfer mode.

In the embodiment of the present application, by sending the complete SDU corresponding to the first SDU segment that has been sent in the first transmission mode in the second transmission mode, the continuity of service transmission can be ensured.

In a possible implementation manner of the second aspect, the first transmission mode is a point-to-point transmission mode, and the second transmission mode is a point-to-multipoint transmission mode. The method further includes: the network device sends second indication information to the terminal device, where the second indication information is used to indicate the serial number SN, and the serial number SN is used to instruct the terminal device to update the parameters of the receiving window according to the SN.

In the embodiment of the present application, when the network device switches from the first transmission mode to the second transmission mode, the network device sends second indication information, and the second indication information indicates the value of the SN. The terminal device may update the parameters of the receiving window according to the value of the SN indicated by the second indication information. Packet loss or data merging errors after switching transmission modes can be prevented.

In a third aspect, a communication method is provided, including: a terminal device receiving first configuration information, where the first configuration information is used to configure at least one first receiving window and at least one second receiving window of a radio link control entity RLC. The first receiving window is used for receiving the first data packet transmitted in the point-to-point transmission mode, and the second receiving window is used for receiving the second data packet transmitted in the point-to-multipoint transmission mode. The terminal device receives the first data packet and/or the second data packet.

In this embodiment of the present application, two receiving windows in an RLC entity are respectively used to receive data packets transmitted in the point-to-point transmission mode and data packets transmitted in the point-to-multipoint transmission mode, and each receiving window maintains its own Receive window variable, packet receive buffer or receive window parameter. In this way, no matter how the point-to-multipoint transmission mode and the point-to-point transmission mode are switched, the network device and the terminal device can maintain the multipoint transmission mode and the point-to-point transmission mode relatively independently.

In a possible implementation manner of the third aspect, the terminal device sends capability information to the network device, where the capability information is used to indicate to the network device that the terminal device supports the same RLC configuration with at least two receiving windows.

In this embodiment of the present application, the network device may send the first configuration information to the terminal device according to the capability information sent by the terminal device.

In a possible implementation of the third aspect, the scheduling information of the second data packet transmitted by using PTM is scrambled by using G-RNTI, and the scheduling information of the first data packet transmitted by using PTP is scrambled by using C-RNTI .

In this embodiment of the present application, the terminal device may decide which receiving window to put the data packet into for processing according to the scrambled RNTI type.

In a fourth aspect, a communication method is provided, comprising: a network device sending first configuration information to a terminal device, where the first configuration information is used to configure at least one first receiving window and at least one first receiving window of a radio link control entity RLC of the terminal device The second receiving window. The first receiving window is used for receiving the first data packet in the point-to-point transmission mode, and the second receiving window is used for receiving the second data packet in the point-to-multipoint transmission mode. Sending the first data packet and/or the second data packet.

In this embodiment of the present application, the network device sends configuration information to the terminal device, which is used to configure at least two receiving windows in one RLC entity of the terminal device. At least two receive windows are respectively used to receive data packets transmitted in point-to-point transmission mode and data packets transmitted in point-to-multipoint transmission mode, and each receive window maintains its own receive window variable, data packet receive buffer or Receive window parameters. In this way, no matter how the point-to-multipoint transmission mode and the point-to-point transmission mode are switched, the network device and the terminal device can maintain the multipoint transmission mode and the point-to-point transmission mode relatively independently.

In a possible implementation manner of the fourth aspect, the network device receives capability information of the terminal device, where the capability information is used to indicate to the network device that the terminal device supports the same RLC configuration with at least two receiving windows.

In a possible implementation manner of the fourth aspect, the scheduling information of the second data packet transmitted by using PTM is scrambled by using G-RNTI, and the scheduling information of the first data packet transmitted by using PTP is scrambled by using C-RNTI .

In the embodiment of the present application, the network device uses G-RNTI to scramble the scheduling information of the second data packet transmitted using PTM, and uses C-RNTI to scramble the scheduling information of the first data packet transmitted using PTP. The terminal device can decide which receiving window to put the data packet into for processing according to the type of scrambled RNTI.

In a fifth aspect, a communication apparatus is provided. The communication apparatus may be a terminal device, comprising: a transceiver module for receiving a first data packet and a second data packet, the first data packet is transmitted in a first transmission mode, and a second data packet The data packets are transmitted through the second transmission mode. A processing module, configured to reassemble the first data packet and/or the second data packet by using the receiving window of the RLC entity. The processing module is further configured to update the parameters of the reception window of the RLC entity when the first transmission mode is switched to the second transmission mode. The receive window is used to reassemble service data unit SDU segments. The parameters of the receiving window include: one or more of a reassembly timer, a receiving state variable, and a receiving window size. The receiving state variable may include the earliest SN (RX_Next_Reassembly) of the SNs waiting for reassembly, the next SN of the SN that triggers the reassembly timer (RX_Timer_Trigger), and the next SN of the largest SN of all received SNs (RX_Next_Highest) one or more of. The first transmission mode and the second transmission mode are one and the other of a point-to-multipoint transmission mode and a point-to-point transmission mode.

In a possible implementation manner of the fifth aspect, the transceiver module is configured to receive first indication information sent by the network device, where the first indication information is used to instruct the first transmission mode to switch to the second transmission mode. The processing module of the terminal device is configured to determine, according to the first indication information, that the transmission mode is switched from the first transmission mode to the second transmission mode, and update the parameters of the receiving window of the RLC entity.

In a possible implementation manner of the fifth aspect, the first indication information may specifically indicate the first transmission mode and/or the second transmission mode, or the first indication information indicates that the transmission mode is switched.

In a possible implementation manner of the fifth aspect, the processing module is configured to determine, according to the second data packet, that the transmission mode is switched from the first transmission mode to the second transmission mode.

In a possible implementation manner of the fifth aspect, the first transmission mode is a point-to-multipoint transmission mode, and the second transmission mode is a point-to-point transmission mode. The parameter used by the processing module to update the receiving window of the RLC entity includes: the parameter used by the processing module to update the receiving window is an initial value, and the initial value may be specified by a protocol.

In the embodiment of the present application, when the network device switches from the first transmission mode to the second transmission mode, the terminal device updates the parameters of the receiving window of the RLC entity to the initial value, which can prevent the loss of data packets or the loss of data packets after switching the transmission mode. Data merge error.

In a possible implementation manner of the fifth aspect, the first transmission mode is a point-to-multipoint transmission mode, and the second transmission mode is a point-to-point transmission mode. The parameters used by the processing module to update the receiving window of the radio link control entity include: the parameters used by the processing module to update the receiving window are the first parameters, and the first parameters are the parameters of the receiving window in the last point-to-point transmission mode. The first parameter may be a parameter of the receiving window of the terminal device when the terminal device receives the last service data unit or service data unit segment transmitted in the last point-to-point transmission mode.

In the embodiment of the present application, when the network device switches from the first transmission mode to the second transmission mode, the terminal device updates the parameters of the receiving window of the RLC entity to the parameters of the receiving window in the last point-to-point transmission mode, Packet loss or data merging errors after switching transmission modes can be prevented.

In a possible implementation manner of the fifth aspect, the first transmission mode is a point-to-point transmission mode, and the second transmission mode is a point-to-multipoint transmission mode. The transceiver module is further configured to receive second indication information sent by the network device, where the second indication information is used to indicate the serial number SN. The processing module used to update the parameters of the receiving window of the RLC entity includes: the processing module is used to update the parameters of the receiving window according to the SN.

In a possible implementation manner of the fifth aspect, the second data packet includes a service data unit SDU segment. The parameters used by the processing module to update the receiving window of the RLC entity include: the processing module is used to update the parameters of the receiving window according to the sequence number SN, and the sequence number SN is the first SDU received by the terminal device in the second transmission mode segment.

In a possible implementation manner of the fifth aspect, the first data packet includes a service data unit SDU segment, and when switching from the first transmission mode to the second transmission mode, the processing module is configured to discard the receiving window in the first transmission mode the received SDU segment.

In a sixth aspect, a communication apparatus is provided, the communication apparatus may be a network device, and includes: a transceiver module configured to send a first data packet in a radio link control entity in a first transmission mode. The processing module is used for switching from the first transmission mode to the second transmission mode. The processing module is further configured to determine the SN of the second data packet. The second data packet may include a service data unit SDU segment, the second data packet includes a packet header, and the packet header includes an SN number of the SDU segment. After receiving the second data packet, the RLC of the terminal device can reassemble the SDU segments according to the SN number in the packet header to assemble a complete SDU, and the RLC of the terminal device sends the assembled complete SDU to the PDCP. The SN number of the second data packet may refer to the SN number allocated to the second data packet by the RLC of the network device. It can also be understood that the network device determines the SN of the second data packet as the network device updates the SN number of the second data packet. A transceiver module, configured to send the second data packet in the RLC entity in a second transmission mode. The first transmission mode and the second transmission mode are one and the other of a point-to-multipoint transmission mode and a point-to-point transmission mode.

In a possible implementation manner of the sixth aspect, the first transmission mode is a point-to-multipoint transmission mode, the second transmission mode is a point-to-point transmission mode, and SN is an initial value. The initial value can be specified by the protocol, for example, the initial value is 1.

In a possible implementation manner of the sixth aspect, the first transmission mode is a point-to-multipoint transmission mode, and the second transmission mode is a point-to-point transmission mode. The processing module configured to determine the SN of the second data packet includes: the processing module is configured to determine the SN according to the first SN, where the first SN is the maximum SN corresponding to the SDU segment transmitted in the last point-to-point transmission mode. The maximum SN refers to the SN with the largest value among the SNs corresponding to the SDU segment transmitted in the last point-to-point transmission mode. The network device may update the SN of the second data packet to the first SN+1. For example, when the first SN is 7, the network device may update the SN of the second data packet to 8.

In a possible implementation manner of the sixth aspect, the first data packet includes a service data unit SDU segment. The transceiver module is configured to send a complete SDU corresponding to the first SDU segment in the second transmission mode, where the first SDU segment is at least one of the SDU segments sent in the first transmission mode. The complete SDU corresponding to the first SDU segment is sent in the second transmission mode, the complete SDU may be sent directly, or all the first SDU segments corresponding to the complete SDU may be segmented in the second sent in transfer mode.

In a possible implementation manner of the sixth aspect, the first transmission mode is a point-to-point transmission mode, and the second transmission mode is a point-to-multipoint transmission mode. The transceiver module is further configured to send second indication information to the terminal equipment, where the second indication information is used to indicate the serial number SN, and the serial number SN is used to instruct the terminal equipment to update the parameters of the receiving window according to the SN.

In this embodiment of the present application, when switching from the first transmission mode to the second transmission mode, the transceiver module is further configured to send second indication information, where the second indication information indicates the value of the SN. The terminal device may update the parameters of the receiving window according to the value of the SN indicated by the second indication information. Packet loss or data merging errors after switching transmission modes can be prevented.

In a seventh aspect, a communication apparatus is provided. The communication apparatus may be a terminal device, and includes: a transceiver module for receiving the first configuration information. The processing module is configured to configure at least one first receiving window and at least one second receiving window of the radio link control entity RLC according to the first configuration information. The first receiving window is used for receiving the first data packet transmitted in the point-to-point transmission mode, and the second receiving window is used for receiving the second data packet transmitted in the point-to-multipoint transmission mode. The transceiver module is further configured to receive the first data packet and/or the second data packet.

In a possible implementation manner of the seventh aspect, the transceiver module is configured to send capability information, where the capability information is used to indicate to the network device that the terminal device supports the same RLC configuration with at least two receiving windows.

In an eighth aspect, a communication device is provided, comprising: a transceiver module for sending first configuration information, where the first configuration information is used to configure at least one first receiving window and at least one second receiving window of a radio link control entity RLC . The first receiving window is used for receiving the first data packet in the point-to-point transmission mode, and the second receiving window is used for receiving the second data packet in the point-to-multipoint transmission mode. The transceiver module is further configured to send the first data packet and/or the second data packet. The processing module is configured to control the transceiver module to send the first configuration information and/or to control the transceiver module to send the first data packet and/or the second data packet.

In a possible implementation manner of the eighth aspect, the transceiver module is further configured to receive capability information of the terminal device, where the capability information is used to indicate to the network device that the terminal device supports the same RLC configuration with at least two receiving windows.

A ninth aspect provides a computer-readable storage medium comprising instructions that, when run on a computer, cause the computer to perform the method of implementing any possible implementation of the first aspect.

A tenth aspect provides a computer-readable storage medium comprising instructions that, when run on a computer, cause the computer to perform the method of implementing any possible implementation of the second aspect.

An eleventh aspect provides a computer-readable storage medium comprising instructions which, when run on a computer, cause the computer to perform the method in any possible implementation of the third aspect.

A twelfth aspect provides a computer-readable storage medium comprising instructions that, when run on a computer, cause the computer to perform the method of implementing any possible implementation of the fourth aspect.

A thirteenth aspect provides a communication apparatus, the communication apparatus includes a memory and a processor, the memory is used for storing instructions, the processor is used for executing the instructions stored in the memory, and processing the instructions stored in the memory Execution causes the processor to execute the method in any possible implementation of the first aspect.

A fourteenth aspect provides a communication device, the communication device includes a memory and a processor, the memory is used for storing instructions, the processor is used for executing the instructions stored in the memory, and processing the instructions stored in the memory. Execution causes the processor to perform the method in any possible implementation of the second aspect.

A fifteenth aspect provides a communication apparatus, the communication apparatus includes a memory and a processor, the memory is used for storing instructions, the processor is used for executing the instructions stored in the memory, and processing the instructions stored in the memory Execution causes the processor to execute the method in any possible implementation manner of the third aspect.

A sixteenth aspect provides a communication apparatus, the communication apparatus includes a memory and a processor, the memory is used for storing instructions, the processor is used for executing the instructions stored in the memory, and processing the instructions stored in the memory. Execution causes the processor to execute the method in any possible implementation manner of the fourth aspect.

A seventeenth aspect provides a communication system, including the communication device of the fifth aspect and the communication device of the seventh aspect.

An eighteenth aspect provides a communication system, including the communication device of the sixth aspect and the communication device of the eighth aspect.

A nineteenth aspect provides a computer program product comprising instructions, the computer program product is used to store a computer program, when the computer program is run on a computer, the computer causes the computer to execute any possible method of the first aspect above method in the implementation.

A twentieth aspect provides a computer program product comprising instructions, the computer program product is used to store a computer program, and when the computer program is run on a computer, the computer causes the computer to execute any possible method of the second aspect above. method in the implementation.

A twenty-first aspect provides a computer program product comprising instructions, the computer program product is used to store a computer program, when the computer program is run on a computer, the computer enables the computer to perform any possibility of the third aspect above method in the implementation.

A twenty-second aspect provides a computer program product containing instructions, the computer program product is used to store a computer program, and when the computer program is run on a computer, the computer enables the computer to perform any possibility of the fourth aspect above method in the implementation.

Description of drawings

FIG. 1 is a schematic diagram of a network architecture to which an embodiment of the present application is applicable;

FIG. 2 is a schematic diagram of another network architecture to which the embodiments of the present application are applicable;

FIG. 3 is a schematic diagram of another network architecture to which the embodiment of the present application is applicable;

4 is a schematic diagram of a multicast broadcast service transmission architecture to which an embodiment of the present application is applicable;

5 is a schematic structural diagram of a protocol stack for transmitting an MBS service provided by an embodiment of the present application;

FIG. 6 is a flowchart of a communication method provided by the first embodiment of the present application;

7 is a flowchart of a communication method provided by the first embodiment of the present application;

8 is a schematic structural diagram of a communication device provided by an embodiment of the present application;

FIG. 9 is another schematic structural diagram of a communication device provided by an embodiment of the present application;

FIG. 10 is another schematic structural diagram of a communication device provided by an embodiment of the present application;

FIG. 11 is another schematic structural diagram of a communication apparatus provided by an embodiment of the present application.

detailed description

The technical solutions in the present application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, but not all, embodiments of the present invention.

First, some terms in the embodiments of the present application are explained to facilitate understanding by those skilled in the art.

1. Terminal device: It can be a wireless terminal device that can receive network equipment scheduling and instruction information. The wireless terminal device can be a device that provides voice and/or data connectivity to users, or a handheld device with wireless connection function, or a connection other processing equipment to the wireless modem. Terminal equipment can communicate with one or more core networks or the Internet via a radio access network (RAN), and the terminal equipment can be a mobile terminal equipment, such as a mobile phone (or "cellular" phone, mobile phone (mobile phone), computer and data cards, for example, may be portable, pocket-sized, hand-held, computer built-in or vehicle mounted mobile devices that exchange language and/or data with the radio access network. For example, personal communication service (PCS) phones, cordless phones, Session Initiation Protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), tablets Computer (Pad), computer with wireless transceiver function and other equipment. Wireless terminal equipment may also be referred to as a system, a subscriber unit, a subscriber station, a mobile station, a mobile station (MS), a remote station, an access point ( access point (AP), remote terminal (remote terminal), access terminal (access terminal), user terminal (user terminal), user agent (user agent), subscriber station (SS), user terminal equipment (customer premises equipment, CPE), terminal (terminal), user equipment (user equipment, UE), mobile terminal (mobile terminal, MT), etc. The terminal device may also be a wearable device and a next-generation communication system, for example, a terminal device in a 5G communication system or a terminal device in a future evolved public land mobile network (PLMN).

In this embodiment of the present application, the device for implementing the function of the terminal may be the terminal, or may be a circuit capable of supporting the terminal to implement the function, for example, a circuit that may be applied to a chip system. The chip system can be installed in a terminal. In this embodiment of the present application, the chip system may be composed of chips, or may include chips and other discrete devices. In the technical solutions provided by the embodiments of the present application, the technical solutions provided by the embodiments of the present application are described by taking the device for realizing the functions of the terminal as a terminal as an example.

2. Network device: It can be a device in a wireless network. For example, a network device can be a radio access network (RAN) node (or device) that connects a terminal device to a wireless network, also known as a base station. At present, some examples of RAN equipment are: generation Node B (gNodeB), transmission reception point (TRP), evolved Node B (evolved Node B, eNB), wireless network in the 5G communication system Controller (radio network controller, RNC), Node B (Node B, NB), base station controller (base station controller, BSC), base transceiver station (base transceiver station, BTS), home base station (for example, home evolved NodeB, Or home Node B, HNB), base band unit (base band unit, BBU), or wireless fidelity (wireless fidelity, Wi-Fi) access point (access point, AP), etc. In addition, in a network structure, the network device may include a centralized unit (centralized unit, CU) node, or a distributed unit (distributed unit, DU) node, or a RAN device including a CU node and a DU node. In addition, in other possible cases, the network device may be other devices that provide wireless communication functions for the terminal device. The embodiments of the present application do not limit the specific technology and specific device form adopted by the network device. For convenience of description, in this embodiment of the present application, a device that provides a wireless communication function for a terminal device is referred to as a network device.

The network equipment may also include core network equipment, the core network equipment may be a 5G core network, and the core network equipment includes but is not limited to: AMF, User plane Function (UPF), Authentication Server Function (AUSF) ), Data Network (DN), Unstructured Data Storage Function (UDFS), Network Exposure Function (NEF), NF Repository Function (NF Repository Function, NRF), Network SliceSelection Function (NSSF), Policy Control Function (PCF), Session Management Function (SMF), Unified Data Management (UDM), Unified Data warehouse function (Unified Data Repository, UDR) or application layer function (Application Function, AF).

The terms "system" and "network" in the embodiments of the present application may be used interchangeably. "At least one" means one or more, and "plurality" means two or more. "And/or", which describes the association relationship of the associated objects, means that there can be three kinds of relationships, for example, A and/or B, which can mean: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A, B can be singular or plural. The character "/" generally indicates that the associated objects are an "or" relationship. "At least one item(s) below" or similar expressions thereof refer to any combination of these items, including any combination of single item(s) or plural items(s). For example "at least one of A, B and C" includes A, B, C, AB, AC, BC or ABC.

And, unless otherwise specified, ordinal numbers such as “first” and “second” mentioned in the embodiments of the present application are used to distinguish multiple objects, and are not used to limit the order, sequence, priority or importance of multiple objects degree. For example, the first threshold and the second threshold are only for distinguishing different thresholds, and do not indicate the difference in priority or importance of the two thresholds.

An optional network architecture applicable to the embodiments of the present application will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of a network architecture to which an embodiment of the present application is applied. As shown in FIG. 1 , the terminal device 130 can be connected to a wireless network to obtain services of an external network (eg, the Internet) through the wireless network, or communicate with other devices through the wireless network, for example, can communicate with other terminal devices. The wireless network includes a radio access network (RAN) device 110 and a core network (core network, CN) device 120, wherein the RAN device 110 is used to access the terminal device 130 to the wireless network, and the CN device 120 is used to connect the terminal device 130 to the wireless network. Manage terminal devices and provide gateways for communication with external networks. It should be understood that the number of each device in the communication system shown in FIG. 1 is only for illustration, and the embodiments of the present application are not limited to this. In practical applications, the communication system may also include more terminal devices 130 and more RAN devices. 110, other devices may also be included.

The CN may include a plurality of CN devices 120. When the network architecture shown in FIG. 1 is suitable for a 5G communication system, the CN devices 120 may be access and mobility management function (AMF) entities, session management Function (session management function, SMF) entity or user plane function (user plane function, UPF) entity, etc. When the network architecture shown in FIG. 1 is applicable to the LTE communication system, the CN device 120 can be a mobility management entity (mobility management entity). entity, MME) and serving gateway (serving gateway, S-GW), etc.

FIG. 2 is a schematic diagram of another network architecture to which this embodiment of the present application is applicable. As shown in Figure 2, the network architecture includes CN equipment, RAN equipment and terminal equipment. The RAN equipment includes a baseband device and a radio frequency device, where the baseband device can be implemented by one node or multiple nodes, and the radio frequency device can be implemented independently from the baseband device, or can be integrated in the baseband device, or some functions Independent integration, some functions are integrated in the baseband device. For example, in an LTE communication system, a RAN equipment (eNB) includes a baseband device and a radio frequency device, wherein the radio frequency device may be arranged remotely relative to the baseband device, for example, a remote radio unit (remote radio unit, RRU) is arranged relative to the BBU remote wireless unit.

The communication between the RAN device and the terminal device follows a certain protocol layer structure. For example, the control plane protocol layer structure may include a radio resource control (RRC) layer, a packet data convergence protocol (packet data convergence protocol, PDCP) layer. , radio link control (radio link control, RLC) layer, media access control (media access control, MAC) layer and physical layer and other protocol layer functions; user plane protocol layer structure can include PDCP layer, RLC layer, MAC layer The functions of protocol layers such as physical layer and physical layer; in a possible implementation, a service data adaptation protocol (SDAP) layer may also be included above the PDCP layer.

A RAN device may implement the functions of protocol layers such as RRC, PDCP, RLC, and MAC by one node, or may implement the functions of these protocol layers by multiple nodes. For example, in an evolved structure, a RAN device may include a CU) and a DU, and multiple DUs may be centrally controlled by one CU. As shown in Figure 2, the CU and DU can be divided according to the protocol layers of the wireless network. For example, the functions of the PDCP layer and above are set in the CU, and the functions of the protocol layers below PDCP, such as the RLC layer and the MAC layer, are set in the DU.

The division of this protocol layer is only an example, and it can also be divided at other protocol layers, for example, at the RLC layer, the functions of the RLC layer and the above protocol layers are set in the CU, and the functions of the protocol layers below the RLC layer are set in the DU; Alternatively, in a certain protocol layer, for example, some functions of the RLC layer and functions of the protocol layers above the RLC layer are placed in the CU, and the remaining functions of the RLC layer and the functions of the protocol layers below the RLC layer are placed in the DU. In addition, it can also be divided in other ways, for example, by time delay, the functions whose processing time needs to meet the delay requirements are set in the DU, and the functions that do not need to meet the delay requirements are set in the CU.

In addition, the radio frequency device may be integrated independently, not placed in the DU, may also be integrated in the DU, or partially remote and partially integrated in the DU, which is not limited herein.

FIG. 3 is a schematic diagram of another network architecture to which this embodiment of the present application is applied. Compared with the network architecture shown in Figure 2, in Figure 3, the control plane (CP) and user plane (UP) of the CU can also be separated and divided into different entities for implementation, namely the control plane (CP) CU entity ( That is, the CU-CP entity) and the user plane (user plane, UP) CU entity (that is, the CU-UP entity).

In the above network architecture, the signaling generated by the CU can be sent to the terminal device through the DU, or the signaling generated by the terminal device can be sent to the CU through the DU. The DU may not parse the signaling, but directly encapsulate it through the protocol layer and transparently transmit it to the terminal device or CU. In the following embodiments, if the transmission of such signaling between the DU and the terminal device is involved, at this time, the sending or receiving of the signaling by the DU includes this scenario. For example, the signaling of the RRC or PDCP layer is finally processed as the signaling of the PHY layer and sent to the terminal device, or is converted from the received signaling of the PHY layer. Under this architecture, the signaling of the RRC or PDCP layer can also be considered to be sent by the DU, or sent by the DU and radio frequency loading.

The network architecture shown in FIG. 1 , FIG. 2 or FIG. 3 can be applied to communication systems of various radio access technologies (RATs), such as an LTE communication system, or a 5G (or referred to as 5G) communication system. The new wireless (new radio, NR) communication system can also be a transition system between the LTE communication system and the 5G communication system. The transition system can also be called a 4.5G communication system, and of course it can also be a future communication system. The network architecture and service scenarios described in the embodiments of the present application are for the purpose of illustrating the technical solutions of the embodiments of the present application more clearly, and do not constitute limitations on the technical solutions provided by the embodiments of the present application. The evolution of the network architecture and the emergence of new service scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

The apparatuses in the following embodiments of the present application may be located in terminal equipment or network equipment according to the functions implemented by them. When the above CU-DU structure is adopted, the network device may be a CU node, or a DU node, or a RAN device including a CU node and a DU node.

FIG. 4 is a schematic diagram of a multicast broadcast service transmission architecture to which an embodiment of the present application is applied. Multicast broadcast service (Multicast and Broadcast Service, MBS) is a service for multiple terminal devices, such as live broadcast service, public safety service, batch software update service, etc.

As shown in FIG. 4 , the MBS service transmission process includes: the MBS service comes from the data server 401. First, the data server 401 sends the MBS data to the core network device 402, then the core network device 402 sends the MBS data to the RAN device 403, and finally the RAN device sends the MBS data to the RAN device 403. 403 Send the MBS data to at least one terminal device that receives the MBS service.

When sending from CN to RAN, MBS services are transmitted through a common transmission channel MBS session, and when sending from RAN to terminal equipment, there are two transmission modes: the first one can use point-to-multipoint (point-to-multipoint) multi-point, PTM) transmission mode, the second can use point to point (point to point, PTP) transmission mode.

The related technical features involved in the embodiments of the present application are introduced below. It should be noted that these explanations are for the purpose of making the embodiments of the present application easier to understand, and should not be regarded as limitations on the protection scope claimed by the present application.

1. PTM transmission mode and PTP transmission mode

The PTM transmission mode may also be called a group scheduling mode or a multicast transmission mode, which refers to a transmission mode in which a certain service sends data to multiple terminal devices simultaneously through a network device. When using PTM transmission, for the same data, a network device, such as a RAN device, receives multiple terminal devices simultaneously in the process of sending. At present, PTM is mainly divided into two types: multimedia broadcast multicast service single frequency network (MBSFN) and single cell point to multipoint (SC-PTM). The MBSFN mode refers to that multiple mutually synchronized cells in the MBSFN area, such as multiple RAN devices, simultaneously transmit the same information to multiple terminal devices. From the point of view of the terminal equipment, the received data is a single superimposed data, which can improve the strength of the received signal and eliminate the interference between cells. The SC-PTM mode means that MBS services are transmitted only through one cell, such as one RAN device, and one network device simultaneously performs group scheduling on multiple terminal devices.

Sending in the PTM transmission mode means: when a device sends a transport block (TB) corresponding to a protocol data unit (PDU), it uses a group radio network temporary identifier (G-RNTI) ) scramble the PDU, or scramble the downlink control information (DCI) corresponding to the PDU, and at the same time one or more devices receive the same PDU according to the same G-RNTI. Alternatively, using the PTM transmission mode to transmit a PDU may refer to informing multiple devices of the location of the same PDU in a semi-static manner, and multiple devices may receive the PDU at the same time. Alternatively, using the PTM transmission mode to transmit a PDU may mean that the PDU is transmitted in a radio bearer established for multicast transmission or in a channel specially designed for multicast transmission.

Receiving in the PTM transmission mode refers to: when the transmitting device transmits in the PTM transmission mode, one device among the plurality of receiving devices receives the PDU according to the G-RNTI. Or one of the plurality of receiving devices receives the PDU through the radio bearer established for the multicast transmission or on the channel used for the multicast transmission.

In this embodiment of the present application, multicast is a specific form of multicast, and therefore, multicast may also be called multicast.

Sending in the PTP transmission mode means: when a device sends the TB corresponding to the PDU, it uses the cell network temporary identifier (C-RNTI) to scramble the PDU, or scramble the DCI corresponding to the PDU. At the same time only one device receives the same PDU according to the C-RNTI. Alternatively, the use of PTP transmission mode to transmit a PDU may mean that the PDU is transmitted in a radio bearer established for unicast or in a channel specially designed for unicast.

Receiving in the PTP transmission mode refers to: when the transmitting device transmits in the PTP transmission mode, a receiving device receives the PDU according to the C-RNTI. Either a receiving device receives via a radio bearer established for unicast transmission or receives on a channel for unicast transmission.

For the protocol stack for transmitting MBS services, PDCP is located above the MAC layer and the RLC layer, and data transmission is from network equipment to terminal equipment. 5 is a schematic diagram of a protocol stack structure for transmitting an MBS service provided by an embodiment of the present application. As shown in FIG. 5 , the dotted line with an arrow represents the data transmission direction, and the data transmission process of the MBS service is as follows:

The data first arrives at the PDCP layer of the network device, and is then transmitted to the RLC layer and the MAC layer after being processed by the PDCP layer of the network device. After processing, it is sent from the physical layer and transmitted to the terminal device through the air interface. Then, each protocol layer of the terminal device sequentially performs corresponding processing on the data packets according to the processing sequence opposite to that of the network device. On the network device side and the terminal device side, the processing of data packets by various layers can be visually combined, which is called wireless bearer. For each data in the wireless bearer, it needs to be processed by each layer, and each layer has corresponding Function entities to perform corresponding functions, such as PDCP entities of the PDCP layer.

Each radio bearer configuration will contain a PDCP entity, and at the same time, the radio bearer configuration will be associated with at least one RLC entity, and each RLC entity corresponds to a logical channel.

In the process of MBS service data transmission, the network device can flexibly decide which transmission mode to use for transmission, that is, it can dynamically switch the transmission mode. In a possible transmission architecture, two RLC entities are used to transmit PTP and PTM respectively. If the MBS data packets from the PDCP layer decide to use the PTP transmission mode, they will be placed in the RLC entity corresponding to the PTP for processing, and then the PTP will be used. The transmission method is sent to the terminal device. On the contrary, after being processed in another RLC entity, it is sent to the terminal number device using the PTM transmission mode. With this protocol stack architecture, the two RLC entities can perform PTP and PTM-related processing respectively, and the network device can perform flexible and dynamic switching between the two different transmission modes.

2. RLC working mode:

Transparent Mode (Transparent Mode, TM): corresponds to the TMRLC entity, referred to as the TM entity. This mode can be considered as the RLC does not do any processing, because in this mode the RLC only provides the pass through function of the data.

Acknowledged Mode (AM): corresponding to the AM RLC entity, referred to as the AM entity. Through error detection and retransmission, AM mode provides a reliable transmission service. This mode provides all RLC functions, including the Automatic Repeat Request (ARQ) function described below.

Unacknowledged Mode (UM): corresponds to the UM RLC entity, referred to as the UM entity. This mode provides all RLC functions except retransmission and re-segmentation, and provides an unreliable transmission service because there is no retransmission function even if the data packet is transmitted in error.

In wireless communication, after the terminal device enters the connected state, when there is a service that needs to be transmitted, the network device will configure the wireless bearer for the terminal device for service transmission. The configuration of the wireless bearer includes the configuration information of RLC, according to the service of the service. Quality of service (QoS) requirements, RLC can be configured to any one of the above working modes. When RLC is configured as UM RLC, if an RLC Service Data Unit (SDU) is not fragmented when it is sent, there is no need to add a sequence number ( Serial Number, SN), if the SDU is segmented when it is sent, the SN needs to be added to the header of the RLC PDU composed of RLC SDU segments. This is because if it is a PDU composed of complete SDUs, the RLC layer of the receiver can directly submit it to the upper layer after receiving it without reading the SN, but for a PDU composed of segmented SDUs, the receiver needs to judge which SDUs are based on the SN in the packet header. The segments belong to the same complete SDU, thus assembling it together.

3. PDU and SDU

Data must be transmitted through the network, and it must be transmitted from the upper layer down layer by layer. If a host wants to transmit data to other hosts, it must first wrap the data in a special protocol header. This process is called encapsulation. The information exchanged between the peer layers by the protocol of the protocol layer is called the protocol data unit PDU. After the data is encapsulated and transmitted over the network, the receiving device deletes the added information and decides how to upload the data up the protocol stack to the appropriate application based on the information in the header.

An SDU is a unit of information that is transmitted from a higher-layer protocol to a lower-layer protocol. There is a one-to-one correspondence between the service data unit SDU of the Nth layer and the protocol data unit (PDU) of the upper layer. The unprocessed data entering each sublayer is called a service data unit (SDU), and the data that is processed by the sublayer and formed into a specific format is called a protocol data unit (PDU). At the same time, the PDU formed by this layer is the SDU of the next layer. According to the data of the protocol data unit, it is sent to the designated layer of the receiving end.

The first data packet and the second data packet in the embodiments of the present application refer to PDU or SDU or PDU segment or SDU segment, and PDU or SDU or or PDU segment or SDU segment are different forms of data packets. In the following example, on the network device side, the first data packet/second data packet from PDCP received by the RLC entity of the network device is the PDCP PDU or RLC SDU, and the RLC entity of the network device can process the RLC SDU as required, The RLC SDU segment is formed. After the RLC entity adds a header to the RLC SDU or RLC SDU segment, it can be called an RLC PDU. The RLC PDU contains the RLC header. For the RLC UM mode, when adding a header to the RLC SDU segment, the header The SN number will be included in the RLC SDU, which is used for the terminal equipment at the receiving end to reassemble the SDU segment; when adding a packet header to the complete RLC SDU, the packet header will not contain the SN number. The same is true for the terminal device side, the first data packet/second data packet received by the terminal device is the PDU or the SDU or the PDU segment or the SDU segment.

Based on the above description of the relevant features, the following provides a specific description of the embodiments of the present application.

The communication method provided by the embodiment of the present application may be based on a single RLC entity protocol stack architecture. It is worth noting that the single RLC entity protocol stack architecture in the present invention is all for the same radio bearer, that is, only one radio bearer has only one An architecture including or associated with one RLC entity may include multiple radio bearers for a terminal device or a base station, that is, a terminal device or a base station may include multiple RLC entities. The protocol stack architecture provided by the embodiment of the present application includes an RLC entity, and the working mode of the RLC entity can be dynamically switched to meet the processing requirements of the data packet transmission mode when dynamically switching between the PTP and PTM transmission modes. When using this protocol stack to dynamically switch the transmission mode, since there is only one RLC, time division multiplexing can be used for RLC processing, that is, when the PTP transmission method is used, the RLC entity performs PTP transmission related processing on the data packets. When the PTM transmission mode is adopted, the RLC entity performs PTM transmission-related processing on the data packets. The communication method provided by the embodiment of the present application uses a single RLC entity protocol stack architecture to switch transmission modes, so that processing data packets through different transmission modes can significantly reduce the specification requirements for terminal equipment and improve data transmission performance.

Exemplarily, the communication method provided in this embodiment of the present application may include two possible solutions, which are referred to as solution one and solution two for convenience of description. The first solution and the second solution are only a general introduction to the technical solutions provided by the embodiments of the present application. It should be noted that this is only for better understanding of the core idea of the technical solutions of the embodiments of the present application, and does not represent a limitation on the embodiments of the present application.

In scheme 1, the terminal device and the network device are the protocol stack architecture of a single RLC entity, the network device sends the first data packet in the first transmission mode, then switches the transmission mode to the second transmission mode, and sends in the second transmission mode. For the second data packet, when the transmission mode is switched, the network device updates the allocation method of the RLC SN, and the terminal device updates the parameters of the receiving window of the RLC entity, thereby ensuring the reliability of service transmission.

In the second solution, the terminal device and the network device are the protocol stack architecture of a single RLC entity, and the RLC entity of the terminal device is configured with at least two receiving windows, which are respectively used to receive data packets transmitted in different transmission modes, thereby ensuring the reliability of service transmission. .

The technical solutions provided by the embodiments of the present application will be described in detail below with reference to the first embodiment and the second embodiment.

first embodiment

The first embodiment describes a possible implementation of the communication method based on the first solution above. FIG. 6 is a flowchart of a communication method provided by the first embodiment of the present application. The communication method of the first embodiment includes:

601: The radio link control entity of the network device sends the first data packet in the first transmission mode, and the radio link entity of the terminal device receives the first data packet. The network device sends the first data packet to the terminal device. The radio link control entity of the network device may be referred to as a transmitter RLC entity, and the radio link control entity of the terminal device may be referred to as a receiver RLC entity.

The first transmission mode may be PTP or PTM. The first data packet may be a data packet of an MBS service, and the network device may be an access network device or a base station. When the first data packet is a data packet related to the MBS service, the first data packet comes from the data server and is sent to the core network device. The core network device sends the first data packet to the base station. The data first arrives at the PDCP layer of the base station, and is processed by the PDCP layer of the base station and then transmitted to the RLC layer and the MAC layer. After processing, it is sent from the physical layer and transmitted to the terminal through the air interface. equipment. Equivalently, the physical layer of the terminal device first receives the first data packet, and after processing, transmits it to higher layers such as the MAC layer, the RLC layer, and the PDCP layer for corresponding processing. The first data packet is sent to the RLC layer after being processed by PDCP, the first data packet received by the RLC layer may be called an RLC SDU, and the first data packet after being processed by the RLC layer may be called an RLC PDU. Here, the first data packet from a higher layer can be called the first data packet when processed by each protocol layer, which means that it is the same data packet, and other data packets are similar.

When the RLC entity at the receiving end receives data from the MAC, it will do the following: 1. Detect whether the RLC SDU or RLC SDU segment is lost. 2. Reassemble the RLC SDU into a complete RLC SDU, and submit it to the PDCP layer after the reorganization is successful. When the RLC is configured in UM mode, only the segmented SDU will be placed in the receiving window, and the complete RLC SDU will be directly submitted. to the PDCP layer. 3. If the reassembly timer expires or the receiving window moves, so that the RLC SDU cannot be reassembled, the received segment corresponding to the SDU is discarded.

602: The network device switches from the first transmission mode to the second transmission mode.

When the first transmission mode is PTM, the second transmission mode may be PTP. When the first transmission mode is PTP, the second transmission mode may be PTM.

The protocol stack architecture of the network device may be a single RLC entity, and switch between the first transmission mode and the second transmission mode in a time-division multiplexing manner.

603: The radio link control entity of the network device determines the SN of the second data packet, sends the second data packet in the second transmission mode, and the radio link control entity of the terminal device receives the second data packet.

In this step, the second data packet may be a data packet related to the MBS service, and the second data packet comes from the data server and is sent to the core network device. The core network device sends the second data packet to the base station. The data first reaches the PDCP layer of the base station, and is processed by the PDCP layer of the base station and then transmitted to the RLC layer and the MAC layer. After processing, it is sent from the physical layer and transmitted to the terminal through the air interface. equipment. Equivalently, the physical layer of the terminal device first receives the second data packet, and after processing, transmits it to higher layers such as the MAC layer, the RLC layer, and the PDCP layer for corresponding processing.

Before sending the second data packet, the RLC entity of the network device may need to assign an SN number to the second data packet. In the RLC UM mode, the second data packet contains an RLC SDU segment. In different transmission modes, the SN number of the SDU segment may be independently set by the RLC entity. For an RLC entity, after the transmission mode is switched, if the allocation of the SN number of the second data packet is not set, the network device will not be able to determine how to allocate the SN to the data packet, which is prone to data packet transmission loss or data merging. wrong situation.

In this embodiment of the present application, after the transmission mode is switched, the network device can improve the reliability of data transmission by determining the SN number of the second data packet. Here, determining the SN of the second data packet can be understood as updating the SN of the second data packet distribution method.

604: When switching from the first transmission mode to the second transmission mode, the terminal device may update the parameters of the receiving window of the RLC entity accordingly to ensure the reliability of data transmission.

The parameters of the receiving window of the RLC entity may include one or more of: a reassembly timer (t-Reassembly), a receiving state variable, and a receiving window size.

The reassembly timer is used by the RLC entity to determine that the data packet is lost. Specifically, when the RLC entity finds that the SDU or SDU segment corresponding to a certain SN number has not been received, it is considered that the SN number triggers the start of the reassembly timer. When the timer expires, it is considered that the SDU or SDU segment corresponding to the SN number is lost.

The receiving state variable may include the earliest SN (RX_Next_Reassembly) of the SNs waiting for reassembly, the next SN of the SN that triggers the reassembly timer (RX_Timer_Trigger), and the next SN of the largest SN of all received SNs (RX_Next_Highest) one or more of. RX_Next_Highest can also be considered as the upper edge of the receive window.

The receiving window size (UM_Window_Size) is a constant used by the RLC entity to determine the SN that can be received without sliding the receiving window forward. The receiving window can be determined by the SN number and the receiving window size corresponding to the lower edge of the receiving window, or by The SN number corresponding to the upper edge of the receiving window and the size of the receiving window are determined. For example, the range of the receive window is determined by using the SN number corresponding to the upper edge of the receive window and the size of the receive window, and the range of the receive window may be (RX_Next_Highest−UM_Window_Size)<=SN<RX_Next_Highest. Taking RX_Next_Highest=10 and UM_Window_Size=5 as an example, the range of SN numbers that can be received by the receiving window without sliding forward is 5<=SN<10. At this time, the SDU segment with the SN number greater than or equal to 5 and less than 10 can be directly put into the receiving window. For SDU segments with SN numbers less than 5, they will be discarded. SDU segments with SN greater than 10 are received in the receive window by sliding the receive window. Specifically, when a new SN=X is received, if X>=RX_Next_Highest, RX_Next_Highest is set to X+1. For example, when a new SN=11 is received, RX_Next_Highest=10, and 11 is greater than RX_Next_Highest, then RX_Next_Highest is set to 11+1, and the receiving window slides forward to update the range of the received SN to 7<=SN<12. Here, the SN may refer to the PDU, PDU segment, SDU or SDU segment corresponding to the SN, one complete SDU corresponds to one SN, and multiple SDU segments belonging to the same complete SDU correspond to the same SN.

It is judged that the transmission mode of the data packet sent by the network device has been switched. At this time, the parameters of the receiving window of the RLC entity need to be updated, and the updated parameters of the receiving window include RX_Next_Highest, the state of the reassembly timer, etc. Data merging errors or packet loss can be prevented by updating the parameters of the receiving window.

In the first embodiment of the present application, the terminal device can determine that the transmission mode has been switched in two ways:

method one:

The terminal device receives the second data packet, which is a data packet generated by the network device through the second transmission mode. When receiving the second data packet, the terminal device can learn which transmission mode the network device transmits. At this time, the terminal device may compare the transmission mode of the currently received second data packet with the transmission mode of the last received data packet, so as to determine whether the transmission mode has been switched.

Method two:

The terminal device receives the first indication information sent by the network device, where the first indication information is used to instruct the first transmission mode to be switched to the second transmission mode. When the terminal device receives the first indication information, it can know that the transmission mode is switched at this time, so as to update the parameters of the receiving window.

The content indicated by the first indication information may include two types: in one case, the first indication information may specifically indicate the first transmission mode and the second transmission mode, for example, the first indication information may indicate that the transmission mode at this time is from point to The multicast transmission mode is switched to the point-to-point transmission mode. In another case, the first indication information may only indicate that the transmission mode is switched, and the specific transmission mode is switched from the point-to-multipoint transmission mode to the point-to-point transmission mode or from the point-to-point transmission mode to the point-to-point transmission mode The multicast mode is not specified. At this time, the terminal device can judge by itself what kind of switching it is. For example, before receiving the first indication information, it uses the point-to-point transmission mode to receive data packets, and after receiving the first indication information, the terminal device can know that it is a point-to-point transmission. The mode is switched to point-to-multipoint transmission mode. In addition, it is also possible to determine which type of switching is by receiving the second data packet. For example, the second data packet is a data packet sent by the network device in the second transmission mode. At this time, the terminal device learns through the first indication information that the transmission mode is switched, and determines through the second data packet that the switched transmission mode is the second transmission mode. When the terminal device makes a judgment, if it is the first transmission mode before switching, it switches from the first transmission mode to the second transmission mode; if it is the second transmission mode before switching, the terminal device considers that the switching has not occurred, and this happens. The reason may be that the terminal device has missed the previous switching command, or the transmission of the network device has an error. The terminal device can report the indication information, indicating that the transmission mode of the network device before and after the switch is the same.

The steps of the first embodiment of the present application will be specifically described below with reference to optional implementations, and at the same time, how to prevent data merging errors and packet loss from occurring in the embodiment of the present application will be described.

1. Switch from PTM to PTP

First, the first transmission mode is PTM and the second transmission mode is PTP as an example for description.

In step 601, the RLC entity of the network device sends the first data packet in PTM, and the RLC entity of the network device can segment the first data packet received from the PDCP layer to form 3 RLC SDU segments, and each The RLC SDU segment adds a header, and the header contains the SN number. The SN numbers of SDU segments belonging to the same complete SDU are the same, for example, the SN number of three RLC SDU segments is 9. The network device sequentially sends the SDU segments to the terminal device. Alternatively, the RLC entity of the network device may also directly transmit a PDU containing a complete SDU to the terminal device without segmenting the first data packet received from the PDCP layer.

The RLC entity of the terminal device receives the first data packet, and buffers the SDU segments in the receiving window. After receiving all the SDU segments belonging to the same complete SDU, the SDU segments are reassembled, and the reassembly is completed and sent to the PDCP . At this time, the parameters of the receiving window can be: the upper edge of the receiving window, RX_Next_Highest, can be set to No. 10. Assuming that the UM_Window_Size of the size of the receiving window is 6, the range of the receiving window is SN No. 4-10. In addition, if the reorganization timer has been started , it may correspond to an SN number in the range of 5-10, or it may not be activated.

In step 602, the network device switches the transmission mode from PTM to PTP. The RLC entity of the network device will send data packets through the switched transmission mode.

In steps 603 and 604, the RLC entity of the network device sends the second data packet by PTP. Before sending the second data packet, the network device needs to determine the SN number of the second data packet. At this time, the network device can use the allocation before the handover. The method or the allocation method of the SN number of the second data packet is updated, and the terminal device correspondingly updates the parameters of the receiving window.

The update of the SN number allocation of the second data packet by the network device needs to be consistent with the update of the parameters of the receiving window by the terminal device. Specifically, there are two update methods:

method one:

The distribution method of the network device updating SN is to start the distribution from the initial value, and the parameter of the terminal device updating the receiving window is the initial value, wherein the initial value can be specified by the protocol or pre-configured by the network device. The RLC entity of the network device can segment the data received from the PDCP layer to form multiple RLC SDU segments, and add a packet header to the SDU segment. The packet header contains an SN number, which is the RLC SN. Before switching the transmission mode, the SN number of the SDU segment of the first data packet has been set to 9. After the transmission mode is switched, the SN number of the SDU segment of the second data packet can be updated to an initial value, such as 0 or 1.

That is to say, after the transmission mode is switched, the RLC entity of the network device updates the way of allocating the SN number. When the transmission mode is switched from PTM to PTP, the terminal device will update the parameters of the receiving window of the RLC entity. By updating the parameters of the receiving window, the occurrence of packet loss during data packet transmission can be prevented. This will be explained in detail below:

It is assumed that after switching the transmission mode, the terminal device does not update the parameters of the receiving window. According to step 601, the receiving window parameter status of the RLC entity of the terminal device is as follows: the upper edge of the receiving window RX_Next_Highest is No. 10, the UM_Window_Size of the receiving window size is 6, and the range of the receiving window is SN No. 4-10. After switching the transmission mode, the SN number of the SDU segment of the second data packet is 1, which falls outside the lower edge of the receiving window. The SDU segment of the second data packet with the SN number of 1 will be discarded and cannot be received by the receiving window, thereby causing packet loss.

In mode 1, when the transmission mode is switched, the terminal device will update the parameters of the receiving window to the initial value. Assuming the initial value is 1, the SDU segment of the second data packet with the SN number of 1 can be placed in the receiving window for waiting. Reassembly to avoid packet loss.

Method two:

The network device determines the SN of the second data packet according to the first SN, where the first SN is the maximum SN corresponding to the SDU segment transmitted in the last point-to-point transmission mode. The terminal device updates the parameter of the receiving window as the first parameter, and the first parameter is the parameter of the receiving window in the last point-to-point transmission mode.

It is assumed that the network device performs two handover processes, the first handover is from PTP to PTM, and the second handover is from PTM to PTP. The second handover is regarded as the current handover, and the first handover is regarded as the last handover. The PTP transmission mode before the last handover may be referred to as the last PTP transmission mode, and the PTP transmission mode in the current handover is referred to as the current PTP transmission mode. The two switching of the network device can be expressed as: the previous PTP transmission mode is switched to the PTM transmission mode, and the PTM transmission mode is switched to the current PTP transmission mode.

In the last PTP transmission mode, the RLC entity of the network device assigns SN numbers to each SDU segment in turn. For example, in the last PTP transmission mode of the RLC entity of the network device, the first SDU includes SDU segment A, SDU segment The SN number of segment B, SDU segment C, SDU segment A, SDU segment B, and SDU segment C is 1, the second SDU includes segment SDU segment D, and the SN number of SDU segment is 2, with By analogy, it is assumed that the SN number of the last SDU segment transmitted in the last PTP transmission mode is 7. The network device saves the SN number 7 as the maximum SN number in the last PTP transmission mode, and the maximum SN number may be called the first SN.

In this switching, the transmission mode of the network device is switched from PTM to PTP, the network device transmits the second data packet in this PTP transmission mode, and updates the SN number of the second data packet before sending the second data packet . The network device will determine the SN of the second data packet based on the first SN. Optionally, the network device may update the SN of the second data packet to the first SN+1. When the first SN is 7, the network device may update the SN of the second data packet to 8.

The process of updating the parameters of the receiving window of the RLC entity by the terminal device is as follows:

Assuming that the SN number of the last SDU transmitted in the last PTP transmission mode is 7, in the PTP transmission mode before the network device performs the first handover, the state of the parameters of the receiving window of the RLC entity of the terminal device may be: receiving window The upper edge of RX_Next_Highest is 8, the UM_Window_Size of the size of the receiving window is 6, and the range of the receiving window is SN number 2-8. The terminal device may save the parameter of the receiving window in the PTP transmission mode before the first switch, and the parameter may be referred to as the first parameter.

According to step 601, although before switching to the PTP transmission mode this time, in the PTM transmission mode, the state of the parameters of the receiving window of the RLC entity of the terminal device is: the upper edge of the receiving window RX_Next_Highest is 10, the size of the receiving window is 10 UM_Window_Size is 6, and the range of the receiving window is SN number 4-10. After switching to the PTP transmission mode this time, the terminal device will update the parameters of the receiving window to the first parameter: the upper edge of the receiving window RX_Next_Highest is 8, the UM_Window_Size of the size of the receiving window is 6, and the range of the receiving window is SN number 2 -8.

When the terminal device receives the second data packet sent by the network device, the SN of the SDU segment of the second data packet is 8, the terminal device, at this time, SN>=RX_Next_Highest, the SDU segment of the second data packet will not be discarded, and the SDU segment of the second data packet will not be discarded. The receive window slide is received by the receive window. This prevents packet loss from occurring.

In addition, optionally, since the data packets transmitted in this PTP transmission mode are different from the data packets transmitted in the previous PTP transmission mode, the terminal device may discard the SDU segments received in the previous PTP transmission mode.

By updating the distribution mode of the SN number of the second data packet by the network device and updating the parameters of the receiving window by the terminal device, it is also possible to prevent the occurrence of data merging errors before and after switching the transmission mode. For example, the RLC entity of the network device receives the data packet sent via the PDCP, and the PDCP adds the PDCP SN to the data packet to form a PDCP PDU before sending the data packet to the RLC. After receiving the PDCP PDU, the RLC entity can choose to segment it to form multiple RLC SDU segments, and add a packet header to each RLC SDU segment, and the packet header contains the RLC SN number. The SN numbers of the SDU segments belonging to the same complete SDU are the same, and the PDCP SN numbers corresponding to the SDU segments belonging to the same complete SDU are also the same. The network device sends SDU segments to the terminal device, and the RLC entity of the terminal device reassembles the SDU segments with the same SN number after receiving the RLC SDU. Generally speaking, the network device will set the same RLC SN for the data packets with the same PDCP SN number, but during the transmission mode switching process, the RLC SN of the data packets with the same PDCP SN number may be different before and after the switching, in other words, it will cause different RLC SNs. The data packets of PDCP SN have the same RLC SN before and after the handover. Since the RLC layer cannot see the PDCP SN number, it may reassemble the SDU segments with the same RLC SN number but different PDCP SN, resulting in errors.

It is assumed that before the transmission mode is switched, the network device transmits a data packet by using the PTM transmission mode. The PDCP SN for this packet is 5, and the RLCSN assigned for the RLC SDU segment is 2. Suppose there are two RLC SDU segments with SN of 2: segment A and segment B. If segment B is lost during transmission, a receiving window will be maintained on the terminal device side, and the SDUA segment with SN of 2 will be stored in it for reassembly. At this time, the SN of the data packet of the PDCP layer corresponding to the RLC SDU segment is 5.

When the network device switches the transmission mode, the network device will use PTP transmission. Since the network device also maintains only one RLC entity, it does not care that when the data packet is transmitted in the PTM transmission mode, the SN of the segmented RLC SDU data packet is set to what number. When the RLC SDU segment needs to be transmitted, the SN number will be set separately for the RLC SDU segment, and then sent to the terminal device. Assuming that the network device sends the SDU segment with the SN number of 2 to the terminal device by PTP, at this time, the PDCPSN corresponding to the SDU segment with the SN number of 2 sent by the PTP may be number 7. When the terminal device receives it, it will combine the SDU segment with RLC SN of 2 transmitted by PTP and the SDU segment of RLC SN of 2 transmitted by PTM. But in essence, the PDCP SN corresponding to the SDU segment whose RLC SN is 2 using PTP transmission is 7, and the PDCP SN corresponding to the SDU segment whose RLC SN is 2 using PTM transmission is 5. Combining the two will result in data packets Receive error.

In the embodiment of the present application, by updating the SN number allocation mode of the second data packet by the network device and updating the parameters of the receiving window by the terminal device, the RLC entity can avoid allocating the same RLC SN number to PDCP data packets with different SN numbers. , causing a data merge error to occur.

As an optional implementation manner, the network device may continue to use the SN allocation method of the second data packet before the transmission mode switching, and the terminal device continues to maintain the parameters of the receiving window before switching the transmission mode after switching the transmission mode.

For example, assuming that the SN number of the SDU segment of the first data packet has been set to 9 before switching the transmission mode, after the transmission mode is switched, the network device updates the SN number of the second data packet to 10, that is, before the switching For the RLC SN used in the PTM transmission mode, set the SN for the RLC SDU segment transmitted in the PTP transmission mode. At this time, the RLC entity of the terminal device can continue to maintain the parameters of the receiving window before switching the mode, and no additional update is required. For example, before switching the transmission mode, the receiving window parameter status of the RLC entity of the terminal device is: the upper edge RX_Next_Highest of the receiving window is No. 10, the UM_Window_Size of the receiving window size is 6, and the range of the receiving window is SN No. 4-10. After switching the transmission mode, the parameters of the receiving window remain unchanged. The terminal device receives the second data packet with the SN number of 10, at this time SN>=RX_Next_Highest, the SDU segment of the second data packet will not be discarded, and is received by the receiving window by sliding the receiving window. This prevents packet loss from occurring.

In the embodiment of the present application, when the transmission mode is switched from PTM to PTP, the network device has a greater degree of freedom in updating the SN of the second data packet. The PTP transmission mode is point-to-point transmission, and the network device only sends data to one terminal. The device sends data without considering the situation of other end devices. Therefore, the network device may set the SN of the second data packet as an initial value, as the maximum SN of the SDU segment transmitted in the last PTP transmission mode, or other values. The network device and the terminal device may agree on an update method in advance, for example, agree on the first method or the second method, or agree on other methods.

As an optional implementation manner, in the process of switching from PTM to PTP, in order to ensure service continuity, after the network device switches from the PTM transmission mode to the PTP transmission mode, at least one SDU transmitted through the PTM may be segmented or The complete RLC SDU corresponding to the SDU segment is transmitted through the PTP transmission method again, so that the RLC SDU can be transmitted through the PTP again even if the transmission through the PTM is unsuccessful. For example, the network device sends SDUs or SDU segments with SN numbers 7, 8, and 9, respectively, through the PTM transmission mode. For example: after switching to the PTP transmission mode, the complete SDU with SN number 9 can be sent again in the PTP transmission mode. Here, the SN of the new data packet is not set to 9, but the data packets that have been sent are repeated. Send, the data packet with the original SN of 9 has been sent once in the PTM transmission mode. In this embodiment of the present application, the data packet is sent again in the PTP transmission mode, thereby ensuring the continuity of service transmission. The retransmission is a complete SDU, or all SDU segments or partial segments corresponding to the complete SDU, and the SN number corresponding to the SDU segment is not limited when retransmitting, and SN=9 can continue to be used. Or use another SN.

2. Switch from PTP to PTM

The following description will be given by taking the first transmission mode as PTP and the second transmission mode as PTM as an example.

In step 601, the RLC entity of the network device sends the first data packet by PTP, and the RLC entity of the network device may segment the first data packet received from the PDCP layer to form 3 RLC SDU segments, and for each The RLC SDU segment adds a header, and the header contains the SN number. The SN numbers of SDU segments belonging to the same complete SDU are the same, for example, the SN number of three RLC SDU segments is 9. The network device sequentially sends the SDU segments to the terminal device. Alternatively, the RLC entity of the network device may also directly transmit a PDU containing a complete SDU to the terminal device without segmenting the first data packet received from the PDCP layer.

In step 602, the network device switches the transmission mode from PTP to PTM. The RLC entity of the network device will send data packets through the switched transmission mode.

In steps 603 and 604, the RLC entity of the network device sends the second data packet by PTP. Before sending the second data packet, the network device needs to determine the SN number of the second data packet, or the SN number of the second data packet. The distribution method is updated.

PTM is a point-to-multipoint transmission mode. The network device sends the same data packet to multiple terminal devices at the same time. In the case of switching from PTP to PTM, the SN setting of the second data packet by the network device needs to be consistent with the ongoing PTM transmission. Be consistent, that is, the addition of the terminal device cannot affect other terminal devices. Therefore, the network device needs to indicate the current latest SN number, or the first SN number that the terminal device should receive, to the terminal device through the second indication information. For example, in the transmission mode of PTP, the network device sends the first data packet to the first terminal device, and the receiving window of the first terminal device buffers the RLC SDU segment with the SN number of 3, and the RLC SDU segment is waiting for reassembly. After the network device switches to the PTM transmission mode, the network device simultaneously sends the second data packet to the first terminal device, the second terminal device and the third terminal device in the PTM transmission mode. If the SN number of the data packet sent by the network device to the second terminal device and the third terminal device is already 5 before the transmission mode of the first terminal device is switched, it is necessary to tell the first terminal device that SN=5, so that the first The terminal device can update the receiving window parameters accordingly, and complete subsequent correct reception. Or the network device does not need to tell the first terminal device that SN=5. After the first terminal device receives the data packet of SN=5 through the PTM transmission mode, it updates the receiving window parameter according to SN=5, for example, SN=5 is used as the receiving window. The first data packet of the window, or as the lower edge of the receive window. That is to say, at this time, the network device will not simply update the SN of the second data packet to the initial value, but will be determined based on the transmission conditions of other terminal devices.

There are two ways for the terminal device to update the parameters of the receiving window:

method one:

After updating the distribution method of the SN of the second data packet, the network device may send second indication information to the terminal device, where the second indication information is used to indicate the SN of the second data packet, and the terminal device updates the receiving window according to the second indication information. parameter. For example, the network device can use the second indication information to indicate that the SN of the second data packet is 4. At this time, the terminal device does not need to receive the data packet according to the receiving window maintained in the PTP transmission mode before the switch, but will receive the first data packet received by the receiving window. If the lower edge of a data packet or receiving window is set to 4, the terminal equipment receiving window expects the SN corresponding to the next received data packet to be 5, and data packets with SN greater than or equal to 4 can be placed in the receiving window. It is assumed here that the SN of the second indication information is 4, and the terminal device sets the first data packet of the receiving window to 4. Alternatively, the terminal device may add 1 to the receiving window according to the SN indicated by the second indication information. The first data packet of is set to 5, and the specific manner in which the terminal obtains the receiving window parameters according to the second indication information is not limited.

Method two:

In mode 2, the network device may not send the second indication information, but directly send the second data packet in the switched transmission mode PTM, and the terminal device determines the parameters of the receiving window according to the received data packet. For example, the SN value of the first SDU segment sent by the network device after switching the transmission mode is 4, and the terminal device updates the parameters of the receiving window according to the SN of the first SDU segment. At this time, the terminal equipment does not need to receive data packets according to the receiving window maintained in the PTP transmission mode before switching, but sets the first data packet received in the receiving window or the lower edge of the receiving window to 4, then the terminal equipment receiving window expects The SN corresponding to the next received data packet is 5, and the data packets whose SN is greater than or equal to 4 can be put into the receiving window. It is assumed here that the terminal device sets the first data packet of the receiving window to 4, or the first data packet of the receiving window can be set to 5 by adding 1 to the SN value of the first SDU segment.

The method for switching from PTP to PTM shown in the first embodiment of this application is also applicable to switching from PTM to PTP. For example, in the case of switching from PTM to PTP, the network device updates the SN of the second data packet to the initial value or the maximum SN of the SDU segment transmitted in the last PTP transmission mode or other values. At this time, the network device can also Sending the second indication information to the terminal device indicates the SN of the second data packet updated by the network device.

In the case of switching from PTP to PTM, when the terminal device determines that the transmission mode is switched, the terminal device may discard the SDU segments received through the PTP transmission mode.

As an optional implementation manner, in order to ensure service continuity, before the network device decides to switch the PTP to the PTM, it needs to ensure that the transmission progress of the PTP is faster than the transmission progress of the PTM. For example, speed up the transmission of PTP until the transmission progress catches up or exceeds the PTM, because if the transmission progress of PTP is slower than that of PTM, some packets will not be received and packets will be lost.

In the first embodiment of the present application, in the protocol stack architecture of a single RLC entity, when the transmission mode is switched, the network device determines the SN of the second data packet, and the terminal device avoids data packet loss or loss by updating the parameters of the receiving window of the RLC entity. The occurrence of data erroneous merging, thereby ensuring the reliability of data transmission.

Second Embodiment

The second embodiment describes a possible implementation of the communication method based on the second solution above. Fig. 7 is a flow chart of a communication method provided by the first embodiment of the present application, and the communication method of the second embodiment includes:

701: The terminal device receives first configuration information sent by the network device, where the first configuration information is used to configure at least one first receiving window and at least one second receiving window of the RLC, and the first receiving window is used to receive The first data packet transmitted in the point-to-point transmission mode, and the second receiving window is used for receiving the second data packet transmitted in the point-to-multipoint transmission mode.

702: The terminal device receives the first data packet and/or the second data packet sent by the network device.

In step 701, the network device sends first configuration information to the terminal device, and the terminal device maintains two receiving windows in one RLC entity according to the first configuration information, which are the first receiving window and the second receiving window respectively. The two receiving windows in an RLC entity are respectively used to receive data packets transmitted in the point-to-point transmission mode and the data packets transmitted in the point-to-multipoint transmission mode, and reassemble the segmented data packets respectively. Each receive window maintains its own receive window variable, data packet receive buffer or receive window parameter. For example, the terminal device puts the data packets received through PTP into the first receiving window for processing, and puts the data packets received through PTM into the second receiving window for processing. After processing, the data packets are all submitted to the same A PDCP entity. On the other hand, the network device independently sets the SNs of the data packets using the PTM and PTP transmission modes. In this way, no matter how PTM and PTP are switched, network equipment and terminal equipment can maintain PTM and PTP transmission relatively independently.

In a possible implementation manner, the scheduling information of the second data packet transmitted by using PTM is scrambled by G-RNTI, and the scheduling information of the first data packet transmitted by using PTP is scrambled by C-RNTI. According to the type of scrambled RNTI, it decides which receiving window to put the data packet into for processing. The further physical layer can identify the RNTI type corresponding to the data packet and send the relevant indication information to the RLC layer, so that the RLC layer can know which receiving window to put the corresponding RLC data packet into for processing.

In a possible implementation manner, the terminal device sends capability information to the network device, where the capability information is used to indicate to the network device that the terminal device supports the same RLC configuration with at least two receiving windows.

The network device may send the first configuration information to the terminal device according to the capability information sent by the terminal device. In the second embodiment of the present application, the capability information may only indicate to the network device the number of receiving windows that the terminal device supports in the same RLC configuration, but does not indicate whether one receiving window is supported for receiving data packets in the PTP transmission mode, The other receiving window is used to receive data packets in the PTM transmission mode. In this case, the capability information may indicate the number of receiving windows that are specifically supported, or the capability information may indicate that at least two receiving windows are supported. Alternatively, the capability information may indicate to the network device that the terminal device supports at least one receive window for receiving data packets transmitted in the PTP transmission mode, and at least one receiving window for receiving data packets transmitted in the PTM transmission mode.

In the second embodiment of the present application, the same RLC entity of the terminal device can maintain two or more receiving windows, which are respectively used to receive data packets transmitted in the PTP transmission mode and data packets transmitted in the PTM transmission mode, thereby avoiding When the transmission mode is switched, a data merging error or a data packet loss occurs, thereby increasing the reliability of data transmission.

The communication method in the embodiments of the present application is described above, and the communication device in each embodiment of the present application will be described below. For example, the apparatus may adopt the methods shown in the embodiments of the present application. Since the principle of solving the problem by the method and the device is similar, the implementation of the device and the method can be referred to each other, and repeated descriptions will not be repeated here.

An embodiment of the present application provides a communication apparatus, and the communication apparatus may be a terminal device or a circuit. The communication apparatus can be used to perform the actions performed by the terminal device in the method of the first embodiment. The communication device includes: a transceiver module for receiving a first data packet and a second data packet, the first data packet is transmitted in a first transmission mode, and the second data packet is transmitted in a second transmission mode. A processing module, configured to reassemble the first data packet and/or the second data packet by using the receiving window of the RLC entity. The processing module is further configured to update the parameters of the reception window of the RLC entity when the first transmission mode is switched to the second transmission mode. The receive window is used to reassemble service data unit SDU segments. The parameters of the receiving window include: one or more of a reassembly timer, a receiving state variable, and a receiving window size. The receiving state variable may include the earliest SN (RX_Next_Reassembly) of the SNs waiting for reassembly, the next SN of the SN that triggers the reassembly timer (RX_Timer_Trigger), and the next SN of the largest SN of all received SNs (RX_Next_Highest) one or more of. The first transmission mode and the second transmission mode are one and the other of a point-to-multipoint transmission mode and a point-to-point transmission mode.

In the embodiment of the present application, when the terminal device determines that the transmission mode of the data packet sent by the network device has been switched, the parameters of the receiving window of the radio link control entity of the terminal device are updated. By updating the parameters of the receiving window, the occurrence of Data merging errors or packet loss.

The communication apparatus provided in the embodiment of the present application can also be used to execute the method in any possible implementation manner of the method in the first embodiment. For details, please refer to the section on the actions performed by the terminal device in the method in the first embodiment. Some content will not be repeated here.

An embodiment of the present application provides a communication apparatus, and the communication apparatus may be a terminal device or a circuit. The communication apparatus can be used to perform the actions performed by the terminal device in the method of the second embodiment. The communication device includes: a transceiver module for receiving the first configuration information. The processing module is configured to configure at least one first receiving window and at least one second receiving window of the radio link control entity RLC according to the first configuration information. The first receiving window is used for receiving the first data packet transmitted in the point-to-point transmission mode, and the second receiving window is used for receiving the second data packet transmitted in the point-to-multipoint transmission mode. The transceiver module is further configured to receive the first data packet and/or the second data packet.

The communication apparatus provided in this embodiment of the present application can also be used to execute the method in any possible implementation manner of the method in the second embodiment. For details, please refer to the section on the actions performed by the terminal device in the method in the first embodiment. Some content will not be repeated here.

FIG. 8 shows a schematic structural diagram of a simplified communication apparatus, which is convenient for understanding and illustration. In FIG. 8 , the communication apparatus takes a terminal device as an example. As shown in FIG. 8 , the communication device includes a processor, a memory, a radio frequency circuit, an antenna, and an input and output device. The processor is mainly used to process communication protocols and communication data, control terminal equipment, execute software programs, and process data of software programs. The memory is mainly used to store software programs and data. The radio frequency circuit is mainly used for the conversion of the baseband signal and the radio frequency signal and the processing of the radio frequency signal. Antennas are mainly used to send and receive radio frequency signals in the form of electromagnetic waves. Input and output devices, such as touch screens, display screens, and keyboards, are mainly used to receive data input by users and output data to users. It should be noted that some types of terminal equipment may not have input and output devices.

When data needs to be sent, the processor performs baseband processing on the data to be sent, and outputs the baseband signal to the radio frequency circuit. The radio frequency circuit performs radio frequency processing on the baseband signal and sends the radio frequency signal through the antenna in the form of electromagnetic waves. When data is sent to the terminal device, the radio frequency circuit receives the radio frequency signal through the antenna, converts the radio frequency signal into a baseband signal, and outputs the baseband signal to the processor, which converts the baseband signal into data and processes the data. For ease of illustration, only one memory and processor are shown in FIG. 8 . In an actual end device product, there may be one or more processors and one or more memories. The memory may also be referred to as a storage medium or a storage device or the like. The memory may be set independently of the processor, or may be integrated with the processor, which is not limited in this embodiment of the present application.

In the embodiments of the present application, the antenna and the radio frequency circuit with a transceiver function can be regarded as a transceiver module of the communication device, and the processor with a processing function can be regarded as a processing module of the communication device. As shown in FIG. 8 , the communication device includes a transceiver module 801 and a processing module 802 . The transceiver module may be a transceiver, a transceiver, a transceiver device, and the like. The processing module may also be a processor, a processing board, a processing device, and the like. Optionally, the device used for implementing the receiving function in the transceiver module 801 may be regarded as a receiving module, and the device used for implementing the sending function in the transceiver module 801 may be regarded as a sending module, that is, the transceiver module 801 includes a receiving module and a sending module. The transceiver module may also sometimes be a transceiver, a transceiver, or a transceiver circuit or the like. The receiving module may also sometimes be a receiver, a receiver, or a receiving circuit or the like. The transmitting module may also be a transmitter, a transmitter or a transmitting circuit sometimes.

It should be understood that the transceiver module 801 is configured to perform the sending and receiving operations on the terminal device side in the above method embodiments, and the processing module 802 is configured to perform other operations on the terminal device in the above method embodiments except for the transceiver operations.

When the communication device is a chip-type device or circuit, the chip device may include a transceiver module and a processing module. Wherein, the transceiver module may be an input/output circuit and/or a communication interface; the processing module is a processor, a microprocessor or an integrated circuit integrated on the chip.

When the communication device in this embodiment of the present application is a terminal device, reference may be made to the device shown in FIG. 9 . In FIG. 9 , the device includes a processor 901 , a transmit data processor 902 , and a receive data processor 903 . The processing module in the above-mentioned embodiment may be the processor 901 in FIG. 9 and perform corresponding functions. The transceiver module in the above embodiment may be the sending data processor 902 and/or the receiving data processor 903 in FIG. 9 . Although a channel encoder and a channel decoder are shown in FIG. 9 , it can be understood that these modules do not constitute a limiting description of this embodiment, but are only illustrative.

FIG. 10 shows another form of this embodiment. The processing device 100 includes modules such as a modulation subsystem, a central processing subsystem, and a peripheral subsystem. The communication apparatus in this embodiment may serve as a modulation subsystem therein. Specifically, the modulation subsystem may include a processor 1003 and an interface 1004 . The processor 1003 completes the function of the above-mentioned processing module, and the interface 1004 implements the function of the above-mentioned transceiver module. As another variant, the modulation subsystem includes a memory 1006, a processor 1003, and a program stored in the memory 1006 and executable on the processor. When the processor 1003 executes the program, the terminal device side in the foregoing method embodiment is implemented. Methods. It should be noted that the memory 1006 may be non-volatile or volatile, and its location may be inside the modulation subsystem or in the processing device 100, as long as the memory 1006 can be connected to the The processor 1003 is sufficient.

An embodiment of the present application provides a communication apparatus, and the communication apparatus may be a network device or a circuit. The communication apparatus can be used to perform the actions performed by the network device in the method of the first embodiment. The communication device includes: a transceiver module for sending a first data packet in a radio link control entity in a first transmission mode. The processing module is used for switching from the first transmission mode to the second transmission mode. The processing module is further configured to determine the SN of the second data packet. The second data packet may include a service data unit SDU segment, the second data packet includes a packet header, and the packet header includes an SN number of the SDU segment. After receiving the second data packet, the RLC of the terminal device can reassemble the SDU segments according to the SN number in the packet header to assemble a complete SDU, and the RLC of the terminal device sends the assembled complete SDU to the PDCP. The SN number of the second data packet may refer to the SN number allocated to the second data packet by the RLC of the network device. It can also be understood that the network device determines the SN of the second data packet as the network device updates the SN number of the second data packet. A transceiver module, configured to send the second data packet in the RLC entity in a second transmission mode. The first transmission mode and the second transmission mode are one and the other of a point-to-multipoint transmission mode and a point-to-point transmission mode.

The communication apparatus provided in the embodiment of the present application can also be used to execute the method in any possible implementation manner of the method in the first embodiment. For details, please refer to the section on the actions performed by the network device in the method in the first embodiment. Some content will not be repeated here.

An embodiment of the present application provides a communication apparatus, and the communication apparatus may be a network device or a circuit. The communication apparatus can be used to perform the actions performed by the network device in the method of the second embodiment. The communication apparatus includes: a transceiver module for sending first configuration information, where the first configuration information is used to configure at least one first receiving window and at least one second receiving window of the radio link control entity RLC. The first receiving window is used for receiving the first data packet in the point-to-point transmission mode, and the second receiving window is used for receiving the second data packet in the point-to-multipoint transmission mode. The transceiver module is further configured to send the first data packet and/or the second data packet. The processing module is configured to control the transceiver module to send the first configuration information and/or to control the transceiver module to send the first data packet and/or the second data packet.

The communication apparatus provided in this embodiment of the present application can also be used to execute the method in any possible implementation manner of the method in the first embodiment. For details, please refer to the section on the actions performed by the network device in the method in the second embodiment. Some content will not be repeated here.

When the communication device in the embodiment of the present application is a network device, the network device may be as shown in FIG. 11 , and the device 110 includes one or more radio frequency units, such as a remote radio unit (remote radio unit, RRU) 1110 and one or more radio frequency units. A baseband unit 1120 (baseband unit, BBU) may also be referred to as a digital unit (digital unit, DU). The RRU 1110 may be referred to as a transceiver module. Optionally, the transceiver module may also be referred to as a transceiver, a transceiver circuit, or a transceiver, etc., which may include at least one antenna 1111 and a radio frequency unit 1112 . The part of the RRU 1110 is mainly used for transmitting and receiving radio frequency signals and converting radio frequency signals and baseband signals, for example, for sending indication information to terminal equipment. The part of the BBU 1110 is mainly used to perform baseband processing, control the base station, and the like. The RRU 1110 and the BBU 1120 may be physically set together, or may be physically separated, that is, a distributed base station.

The BBU 1120 is the control center of the base station, and can also be called a processing module, which can correspond to the processing module 802 in FIG. 8 , and is mainly used to complete baseband processing functions, such as channel coding, multiplexing, modulation, spread spectrum, and the like. For example, the BBU (processing module) may be used to control the base station to perform the operation procedure of the network device in the foregoing method embodiments, for example, to generate the foregoing indication information and the like.

In an example, the BBU 1120 may be composed of one or more single boards, and the multiple single boards may jointly support a wireless access network of a single access standard, or may respectively support a wireless access network of different access standards ( Such as LTE network, 5G network or other network). The BBU 1120 also includes a memory 1121 and a processor 1122. The memory 1121 is used to store necessary instructions and data. The processor 1322 is configured to control the base station to perform necessary actions, for example, to control the base station to perform the operation flow of the network device in the foregoing method embodiments. The memory 1121 and the processor 1122 may serve one or more single boards. That is to say, the memory and processor can be provided separately on each single board. It can also be that multiple boards share the same memory and processor. In addition, necessary circuits may also be provided on each single board.

The above are only specific embodiments of the present application, but the protection scope of the present application is not limited to this. should be covered within the scope of protection of this application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

A communication method, comprising:

the radio link control entity receives the first data packet, and the first data packet is transmitted in the first transmission mode;

When the first transmission mode is switched to the second transmission mode, updating the parameters of the reception window of the RLC entity;

receiving, by the radio link control entity, a second data packet, the second data packet being transmitted through the second transmission mode;

The first transmission mode and the second transmission mode are one and the other of a point-to-multipoint transmission mode and a point-to-point transmission mode.
The method according to claim 1, wherein when the first transmission mode is switched to the second transmission mode, updating the parameters of the receiving window of the RLC entity comprises:

receiving first indication information, where the first indication information is used to instruct the first transmission mode to switch to the second transmission mode; or

It is determined according to the second data packet that the first transmission mode is switched to the second transmission mode.
The method according to claim 1 or 2, characterized in that,

the first transmission mode is the point-to-multipoint transmission mode, and the second transmission mode is the point-to-point transmission mode;

The updating the parameter of the receiving window of the RLC entity includes: updating the parameter of the receiving window to an initial value.
The method of claim 3, wherein

the first transmission mode is the point-to-multipoint transmission mode, and the second transmission mode is the point-to-point transmission mode;

The updating the parameter of the receiving window of the RLC entity includes: updating the parameter of the receiving window to be a first parameter, and the first parameter is the parameter of the receiving window in the last point-to-point transmission mode .
The method according to claim 1 or 2, characterized in that,

the first transmission mode is the point-to-point transmission mode, and the second transmission mode is the point-to-multipoint transmission mode;

The method further includes: receiving second indication information, where the second indication information is used to indicate a sequence number SN, and the updating the parameter of the receiving window of the RLC entity includes: updating the receiving window according to the SN window parameters.
The method according to claim 1 or 2, characterized in that,

the second data packet includes a service data unit SDU segment;

The updating the parameters of the receiving window of the RLC entity includes: updating the parameters of the receiving window according to the sequence number SN, where the SN is the first SDU packet received in the second transmission mode. The SN corresponding to the segment.
The method of claim 5 or 6, further comprising:

The first data packet includes a service data unit SDU segment, and when switching from the first transmission mode to the second transmission mode, the SDU segment received by the receive window in the first transmission mode is discarded.
A communication method, comprising:

the RLC entity sends the first data packet in the first transmission mode;

switching from the first transmission mode to the second transmission mode;

determining the SN of the second data packet;

The RLC entity sends the second data packet in a second transmission mode, and the first transmission mode and the second transmission mode are one of a point-to-multipoint transmission mode and a point-to-point transmission mode and another.
The method of claim 8, wherein:

The first transmission mode is the point-to-multipoint transmission mode, the second transmission mode is the point-to-point transmission mode, and the SN is an initial value.
The method of claim 8, wherein:

the first transmission mode is the point-to-multipoint transmission mode, the second transmission mode is the point-to-point transmission mode,

The determining the SN of the second data packet includes: determining the SN according to the first SN, where the first SN is the maximum SN corresponding to the SDU segment transmitted in the last point-to-point transmission mode .
The method according to any one of claims 8-10, wherein,

A complete SDU corresponding to a first SDU segment is transmitted in the second transmission mode, the first SDU segment being at least one of the SDU segments transmitted in the first transmission mode.
The method of claim 8, wherein:

the first transmission mode is the point-to-point transmission mode, and the second transmission mode is the point-to-multipoint transmission mode;

The method further includes: sending second indication information, where the second indication information is used to indicate a sequence number SN, and the SN is used to indicate that a parameter of the receiving window is updated according to the SN.
A communication method, comprising:

receiving first configuration information, where the first configuration information is used to configure at least one first receiving window and at least one second receiving window of the radio link control entity RLC;

The first receiving window is used for receiving the first data packet transmitted by the point-to-point transmission mode, and the second receiving window is used for receiving the second data packet transmitted by the point-to-multipoint transmission mode;

The first data packet and/or the second data packet are received.
The method of claim 13, further comprising:

Sending capability information, where the capability information is used to indicate that at least two receiving windows are supported for the same RLC configuration.
A communication method, characterized in that,

sending first configuration information, where the first configuration information is used to configure at least one first receiving window and at least one second receiving window of the RLC;

The first receiving window is used for receiving the first data packet in the point-to-point transmission mode, and the second receiving window is used for receiving the second data packet in the point-to-multipoint transmission mode;

Sending the first data packet and/or the second data packet.
The method of claim 15, further comprising:

Receiving capability information, where the capability information is used to indicate that at least two receiving windows are supported for the same RLC configuration.
A communication device, comprising:

A transceiver module for receiving a first data packet and a second data packet, the first data packet is transmitted by the first transmission mode, and the second data packet is transmitted by the second transmission mode;

a processing module, configured to reassemble the first data packet and/or the second data packet by using the receiving window of the RLC entity;

The processing module is further configured to update the parameters of the receiving window of the RLC entity when the first transmission mode is switched to the second transmission mode;

The first transmission mode and the second transmission mode are one and the other of a point-to-multipoint transmission mode and a point-to-point transmission mode.
The apparatus of claim 17, wherein when the first transmission mode is switched to the second transmission mode, updating the parameters of the receiving window of the RLC entity comprises:

the transceiver module, configured to receive first indication information, where the first indication information is used to instruct the first transmission mode to switch to the second transmission mode; or

The transceiver module is configured to determine that the first transmission mode is switched to the second transmission mode according to the second data packet.
The device of claim 17 or 18, wherein:

the first transmission mode is the point-to-multipoint transmission mode, and the second transmission mode is the point-to-point transmission mode;

The processing module used to update the parameters of the receiving window of the RLC entity includes: the processing module is used to update the parameters of the receiving window to an initial value.
The apparatus of claim 19, wherein

the first transmission mode is the point-to-multipoint transmission mode, and the second transmission mode is the point-to-point transmission mode;

The parameters used by the processing module to update the receiving window of the RLC entity include: the parameter used by the processing module to update the receiving window is a first parameter, and the first parameter is the last point-to-point Parameters of the receiving window in transmission mode.
The device of claim 17 or 18, wherein:

the first transmission mode is the point-to-point transmission mode, and the second transmission mode is the point-to-multipoint transmission mode;

The transceiver module is further configured to receive second indication information, where the second indication information is used to indicate the serial number SN, and the processing module is used to update the parameters of the receiving window of the radio link control entity, comprising: a processing module for updating the parameters of the receiving window according to the SN.
The device of claim 17 or 18, wherein:

the second data packet includes a service data unit SDU segment;

The processing module is used to update the parameters of the receiving window of the RLC entity comprising: the processing module is used to update the parameters of the receiving window according to the sequence number SN, and the SN is in the second transmission mode. The first described SDU segment received next.
The device of claim 21 or 22, wherein:

The first data packet includes a service data unit SDU segment, and the processing module is further configured to discard the SDU segment received by the receiving window in the first transmission mode.
A communication device, comprising:

a transceiver module, configured to send the first data packet in the RLC entity in the first transmission mode;

a processing module for switching from the first transmission mode to the second transmission mode;

The processing module is further configured to determine the SN of the second data packet;

the transceiver module, configured to send the second data packet in the RLC entity in a second transmission mode;

The first transmission mode and the second transmission mode are one and the other of a point-to-multipoint transmission mode and a point-to-point transmission mode.
The apparatus of claim 24, wherein

The first transmission mode is the point-to-multipoint transmission mode, the second transmission mode is the point-to-point transmission mode, and the SN is an initial value.
The apparatus of claim 24, wherein

the first transmission mode is the point-to-multipoint transmission mode, the second transmission mode is the point-to-point transmission mode,

The processing module configured to determine the SN of the second data packet includes: the processing module is configured to determine the SN according to the first SN, and the first SN is the last point-to-point The maximum SN corresponding to the SDU segment transmitted in transmission mode.
The device according to any one of claims 24-26, characterized in that,

the first data packet includes a service data unit SDU segment;

The transceiver module is further configured to send a complete SDU corresponding to a first SDU segment in the second transmission mode, where the first SDU segment is the SDU segment sent in the first transmission mode. at least one of the segments.
The apparatus of claim 24, wherein

the first transmission mode is the point-to-point transmission mode, and the second transmission mode is the point-to-multipoint transmission mode;

The transceiver module is further configured to send second indication information, where the second indication information is used to indicate the sequence number SN, and the SN is used to indicate that the parameters of the receiving window are updated according to the SN.
A communication device, comprising:

a transceiver module for receiving the first configuration information;

a processing module, configured to configure at least one first receiving window and at least one second receiving window of the radio link control entity RLC according to the first configuration information;

The first receiving window is used for receiving the first data packet transmitted by the point-to-point transmission mode, and the second receiving window is used for receiving the second data packet transmitted by the point-to-multipoint transmission mode;

The transceiver module is further configured to receive the first data packet and/or the second data packet.
The apparatus of claim 29, wherein:

The transceiver module is further configured to send capability information, where the capability information is used to indicate that at least two receive windows are supported for the same RLC configuration.
A communication device, characterized in that:

a transceiver module, configured to send first configuration information, where the first configuration information is used to configure at least one first receiving window and at least one second receiving window of the RLC;

The first receiving window is used for receiving the first data packet in the point-to-point transmission mode, and the second receiving window is used for receiving the second data packet in the point-to-multipoint transmission mode;

a transceiver module, further configured to send the first data packet and/or the second data packet;

A processing module, configured to control the transceiver module to send the first configuration information and/or to control the transceiver module to send the first data packet and/or the second data packet.
The apparatus of claim 31, wherein

The transceiver module is further configured to receive capability information, where the capability information is used to indicate that the same RLC configuration at least two reception windows is supported.
A computer-readable storage medium comprising instructions which, when executed on a computer, cause the computer to perform the method of any of claims 1-16.
A communication device, comprising a memory and a processor, the memory is used for storing instructions, the processor is used for executing the instructions stored in the memory, and executes the instructions stored in the memory according to any one of claims 1-7. A method as claimed in any of claims 13-14 or performing a method as claimed in any of claims 13-14.
A communication device, comprising a memory and a processor, the memory is used for storing instructions, the processor is used for executing the instructions stored in the memory, and executes the instructions stored in the memory according to any one of claims 8-12. A method as claimed in any one of claims 15-16 or performing the method.
A communication system, characterized by comprising the communication device according to any one of claims 17-23, and the communication device according to any one of claims 24-28; or

Comprising a communication device as claimed in any of claims 29-30, and a communication device as claimed in any of claims 31-32.
A computer program, characterized in that, when the computer program is run on a computer, the computer is caused to execute the communication method according to any one of claims 1-16.