Communication method and communication apparatus

Abstract

The present application provides a communication method and a communication apparatus. The method may be applied to a first network device, and the first network device is a network device connected to a terminal device after handover. The method may comprise: determining first information, the first information indicating first data, the first data being data discarded by a second network device, and the second network device being a network device connected to the terminal device before handover; and sending the first information to the terminal device, the first information being used for causing the terminal device to consider that the first data has been discarded. In the present application, by means of a sender device after handover indicating to a receiver device data discarded before handover, the waiting delay can be reduced.

Description

A communication method and a communication apparatus

[0001] The present application claims priority to the Chinese Patent Application No. 202410865720.8, filed on June 28, 2024, and entitled "A communication method and a communication apparatus", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the field of communication, and more particularly, to a communication method and a communication apparatus. BACKGROUND

[0003] Extended reality (XR) refers to various types of reality and virtual combination environments generated by computing technology and wearable devices, as well as human-computer interaction. XR services usually have high latency requirements, and the packet data convergence protocol (PDCP) layer at the sending side performs packet discard operations.

[0004] In order to support terminal mobility, inter-station handover can be implemented in XR services, that is, a terminal device can switch connections between different network devices. After inter-station handover, the receiving side device may continue to wait for the discarded data packets, causing additional waiting latency. Therefore, how to reduce the waiting latency is a problem to be solved in the field. SUMMARY

[0005] The present application provides a communication method and a communication apparatus, which can reduce the waiting latency by indicating the discarded data before handover to the receiving device by the sending device after handover.

[0006] In a first aspect, a communication method is provided. The method can be applied to the network side, that is, the method can be executed by a network device, or can be executed by a component (such as a chip or a chip system or a circuit or a communication module) of the network device, which is not limited in the present application. Hereinafter, the network device will be mainly taken as an example for description.

[0007] The method is applied to a first network device, which is a network device connected after terminal device handover. The method can include: determining first information, the first information indicating first data, the first data being discarded by a second network device, the second network device being a network device connected before terminal device handover; and sending the first information to the terminal device, the first information being used to make the terminal device consider that the first data has been discarded.

[0008] The first information can also be referred to as a packet loss information, a packet loss report, a hole report, or a sequence number hole report, or a packet data convergence protocol sequence number hole report (PDCP SN gap report), etc.

[0009] Optionally, before the first network device sends the first information, if the first network device itself has new packet loss, the first data can also include the data discarded by the first network device, and the first network device indicates the terminal device through the first information.

[0010] As an example, the first information is used to make the terminal device consider that the first data has been discarded, so that after the terminal device receives the first information, the terminal device can not continue to wait for the first data, or in other words, the terminal device can stop detecting or stop receiving the first data, or in other words, the terminal device can stop or not start a timer for waiting for the first data.

[0011] Based on the above technical solution, the first network device can indicate the first data discarded by the second network device connected with the terminal device before the inter-station handover to the terminal device, so that the terminal device can consider that the first data has been discarded, so that the terminal device can not continue to wait for the first data discarded before the handover, avoiding the influence of the packet loss occurring before the handover on the waiting delay of the data after the handover. The terminal device can update the receiving window in time to achieve the effect of reducing the waiting delay of the terminal device.

[0012] In combination with the first aspect, in some implementations of the first aspect, before the first information is sent to the terminal device, the method can further include: determining a first index, the first index being a minimum index corresponding to the data forwarded by the second network device to the first network device; determining a second index, the second index being a next index allocated by the first network device for the data sent to the terminal device; the index corresponding to the first data being greater than the first index and less than the second index.

[0013] Specifically, the first network device checks a PDCP SN gap between the first index and the second index, which can be understood as the packet loss of the second network device, or in other words, the packet loss before the handover, and the first data can include all or part of the data corresponding to the gap.

[0014] Based on the above technical solution, the first network device can obtain the index corresponding to the first data discarded by the second network device through the data forwarded by the second network device and the next index allocated by the first network device for the data sent to the terminal device, without the second network device indicating the first network device with additional signaling overhead.

[0015] In some implementations of the first aspect, before sending the first information to the terminal device, the method further includes receiving second information from the second network device, the second information indicating the first data.

[0016] As an example, the second information can also be referred to as packet loss transfer information or PDCP SN gap transfer information, etc.

[0017] As an example, the second network device can send the second information to the first network device during the inter-station handover process, to indicate the SN information of the first data discarded by the second network device.

[0018] Optionally, the second information can include the content of the PDCP SN gap report last generated by the second network device, or the content of the PDCP SN gap report generated by the second network device after initiating the handover request, or the content of the PDCP SN gap report generated by the second network device but not yet sent to the terminal device, or the content of the PDCP SN gap report that has not been correctly received by the terminal device.

[0019] Based on the above technical solution, the second network device directly indicates the first data discarded before handover to the first network device, so that the first network device can more accurately understand the packet loss of the second network device, and the problem that the first network device cannot determine the packet loss information by itself when the packet loss data is located before the forwarded data is solved, and the additional waiting delay caused by the terminal device continuing to wait for the discarded packet due to the terminal device not knowing the packet loss of the second network device after handover is avoided.

[0020] In some implementations of the first aspect, before sending the first information to the terminal device, the method further includes receiving third information, the third information indicating that the terminal device has not received the first data.

[0021] As an example, the third information can be a PDCP status report of the terminal device, indicating the PDCP sequence number of the data that has not been received by the terminal device (or referred to as the data that has not been received, the data that is waiting to be received), and / or the PDCP sequence number of the data that has been received by the terminal device.

[0022] As an example, after the first network device determines the gap existing in the forwarded data, the third information can be received, which indicates that the terminal device has not received the first data. If the first data is indicated as not received in the third information, and the first data is located in the gap existing in the forwarded data, the first network device determines and sends the first information to indicate the first data to the terminal device.

[0023] Based on the technical solution, the terminal device indicates to the first network device that it has not received the first data, indicating that the terminal device is still waiting to receive the first data. That is, the first network device will indicate to the terminal device the first data discarded by the second network device through the first information only after determining that the terminal device is still waiting to receive the first data, thereby preventing the first network device from indicating unnecessary data in the first information and avoiding waste of indication overhead.

[0024] In a second aspect, a communication method is provided. The method can be applied to the terminal side, that is, the method can be executed by a terminal device or a component (such as a chip or a chip system or a circuit or a communication module) of the terminal device, and the present application does not limit this. Hereinafter, the terminal is mainly taken as an example for description.

[0025] The method can include: receiving first information from a first network device, the first network device being a network device connected after terminal device switching, the first information indicating first data, the first data being data discarded by a second network device, the second network device being a network device connected before terminal device switching; considering that the first data has been discarded.

[0026] In combination with the second aspect, in some implementations of the second aspect, before the receiving first information from the first network device, the method can further include: sending third information, the third information indicating that the terminal device has not received the first data.

[0027] In combination with the second aspect, in some implementations of the second aspect, before the sending third information, the method can further include: receiving fourth information, the fourth information indicating second data, the second data being data discarded by the second network device; and the third information further indicating that the terminal device has received the second data.

[0028] As an example, the terminal device obtains that the second data is discarded by the second network device before switching. Even if the terminal device actually does not receive the second data after switching, the terminal device can indicate that the second data has been received through the third information to the first network device, or the terminal device can not indicate that the second data has not been received in the third information to the first network device.

[0029] Since the third information does not indicate that the terminal device has not received the second data, the first information sent by the first network device indicates the first data, and the intersection of the first data and the second data is empty, that is, the second data will not be indicated in the first information.

[0030] Based on the technical solution, the terminal device knows that the second network device discards the second data, and thus does not wait for the second data. The terminal device indicates, to the first network device, that the second data is received data, so that the first network device considers that the terminal device has received the second data, and thus the first network device does not indicate the second data in the first information, preventing the first network device from indicating unnecessary data in the first information, and avoiding waste of indication overhead.

[0031] The beneficial effects and possible designs of the second aspect can be referred to the related description of the first aspect, which will not be repeated here.

[0032] In a third aspect, a communication method is provided. The method can be applied to the terminal side, that is, the method can be executed by a terminal device, or can be executed by a component (such as a chip or a chip system or a circuit or a communication module) of the terminal device, which is not limited in the present application. Hereinafter, the terminal will be mainly taken as an example for description.

[0033] The method can include: determining first information, the first information indicating first data, the first data being data discarded by the terminal device when connecting with a second network device, the second network device being a network device connected before handover of the terminal device; and sending the first information to a first network device, the first network device being a network device connected after handover of the terminal device, the first information being used to make the first network device consider that the first data has been discarded.

[0034] Optionally, the first information can include content of a PDCP SN gap report last generated by the terminal device before handover, or content of a PDCP SN gap report generated by the terminal device but not yet sent to the second network device, or content of a PDCP SN gap report not yet correctly received by the second network device.

[0035] Optionally, after inter-station handover, before the terminal device sends the first information, if the terminal device has new packet loss, the first data can also include data discarded by the terminal device after handover, and is indicated to the first network device through the first information.

[0036] As an example, the first information is used to make the first network device consider that the first data has been discarded, so that after receiving the first information, the first network device can not continue to wait for the first data, or in other words, the first network device can stop detecting or receiving the first data, or in other words, the first network device can stop or not start a timer for waiting for the first data.

[0037] Based on the technical solution, the terminal device can indicate the first data discarded by the terminal device before the inter-station handover to the first network device, so that the first network device can consider that the first data has been discarded, and thus the first network device can not continue to wait for the first data discarded before the handover, avoiding the influence of the packet loss before the handover on the waiting time delay of data after the handover. The first network device can update the receiving window in time, achieving the effect of reducing the waiting time delay of the first network device.

[0038] In combination with the third aspect, in some implementations of the third aspect, before the sending of the first information to the first network device, the method can further include: receiving third information, the third information indicating that the first network device has not received the first data.

[0039] As an example, the third information can be a PDCP status report of the first network device, indicating a PDCP sequence number of data that has not been received (or, data that is not received, data that is waiting to be received) by the first network device, and / or a PDCP sequence number of data that has been received by the first network device.

[0040] As an example, if the first data is indicated as not received in the third information, and the first data is in the data discarded by the terminal device before the handover, the terminal device determines and sends the first information to indicate the first data to the first network device.

[0041] Based on the technical solution, the first network device indicates to the terminal device that it has not received the first data, indicating that the first network device is still waiting to receive the first data, that is, the terminal device determines that the first network device is still waiting to receive the first data, and then indicates the first data discarded before the handover to the first network device through the first information, thereby preventing the terminal device from indicating unnecessary data in the first information and avoiding waste of indication overhead.

[0042] The fourth aspect provides a communication method. The method can be applied to the network side, that is, the method can be executed by a network device or a component (such as a chip or a chip system or a circuit or a communication module) of the network device, and the present application does not limit this. Hereinafter, the network device will be mainly taken as an example for description.

[0043] The method is applied to a first network device, which is a network device connected after a terminal device handovers. The method can include: receiving first information from the terminal device, the first information indicating first data, the first data being data discarded when the terminal device is connected to a second network device, the second network device being a network device connected before the terminal device handovers; considering that the first data has been discarded.

[0044] In some implementations of the fourth aspect, before the receiving the first information from the terminal device, the method further includes: sending third information, the third information indicating that the first network device does not receive the first data.

[0045] In some implementations of the fourth aspect, before the sending the third information, the method further includes: receiving fourth information, the fourth information indicating that the second network device has received second data, the second data being data discarded by the terminal device when the terminal device is connected with the second network device; and the third information further indicates that the first network device has received the second data.

[0046] For example, the second network device obtains the second data discarded by the terminal device before the handover, and after the handover, the second network device indicates that the second data has been received by the first network device through the fourth information, or the second network device does not indicate that the second data has not been received by the first network device in the fourth information.

[0047] Further, after the first network device receives the fourth information, for the second data, the first network device does not continue to wait for the second data, or in other words, the first network device can stop detecting or receiving the second data, or in other words, the first network device can stop or not start a timer for waiting for the second data, and instead considers that the second data has been received or delivered.

[0048] Based on the above technical solution, the second network device indicates to the first network device that the second data discarded by the terminal device has been received, so that the first network device does not wait for the second data, and the first network device can update the receiving window in time, thereby reducing the waiting delay of the first network device.

[0049] Further, the first network device indicates to the terminal device that the second data has been received, so that the terminal device considers that the first network device has received the second data, and the terminal device does not indicate the second data in the first information, thereby preventing the terminal device from indicating unnecessary data in the first information, and avoiding waste of indication overhead.

[0050] The beneficial effects and possible designs of the fourth aspect can be referred to the related description of the third aspect, and will not be repeated here.

[0051] In a fifth aspect, a communication apparatus is provided. The apparatus can comprise: a processing unit, configured to determine first information, the first information indicating first data, the first data being data discarded by a second network device, the second network device being a network device connected by a terminal device before handover; and a transceiver, configured to send the first information to the terminal device, the first information being used for the terminal device to consider that the first data has been discarded.

[0052] With reference to the fifth aspect, in some implementations of the fifth aspect, the processing unit is further configured to determine a first index, the first index being a smallest index corresponding to data forwarded by the second network device to the first network device; and determine a second index, the second index being a next index allocated by the first network device for data sent to the terminal device; and the index corresponding to the first data is greater than the first index and less than the second index.

[0053] With reference to the fifth aspect, in some implementations of the fifth aspect, the transceiver is further configured to receive second information from the second network device, the second information indicating the first data.

[0054] With reference to the fifth aspect, in some implementations of the fifth aspect, the transceiver is further configured to receive third information, the third information indicating that the terminal device has not received the first data.

[0055] In a sixth aspect, a communication apparatus is provided. The apparatus can comprise: a transceiver, configured to receive first information from a first network device, the first information indicating first data, the first data being data discarded by a second network device, the second network device being a network device connected by a terminal device before handover; and a processing unit, configured to consider that the first data has been discarded.

[0056] With reference to the sixth aspect, in some implementations of the sixth aspect, the transceiver is further configured to send third information, the third information indicating that the terminal device has not received the first data.

[0057] With reference to the sixth aspect, in some implementations of the sixth aspect, the transceiver is further configured to receive fourth information, the fourth information indicating second data, the second data being data discarded by the second network device; and the third information further indicates that the terminal device has received the second data.

[0058] In a seventh aspect, a communication apparatus is provided. The apparatus can comprise: a processing unit, configured to determine first information, the first information indicating first data, the first data being data discarded when the terminal device connects with a second network device, the second network device being a network device connected before the terminal device performs handover; and a transceiver, configured to send the first information to a first network device, the first information being used for the first network device to consider that the first data has been discarded.

[0059] With reference to the seventh aspect, in some implementations of the seventh aspect, the transceiver is further configured to receive third information, the third information indicating that the first data is not received by the first network device.

[0060] In an eighth aspect, a communication apparatus is provided. The apparatus can comprise: a transceiver, configured to receive first information from a terminal device, the first information indicating first data, the first data being data discarded when the terminal device connects with a second network device, the second network device being a network device connected before the terminal device performs handover; and the transceiver is further configured to consider that the first data has been discarded.

[0061] With reference to the eighth aspect, in some implementations of the eighth aspect, the transceiver is further configured to send third information, the third information indicating that the first data is not received by the first network device.

[0062] With reference to the eighth aspect, in some implementations of the eighth aspect, the transceiver is further configured to receive fourth information, the fourth information indicating that the second network device has received second data, the second data being data discarded when the terminal device connects with the second network device; and the third information further indicates that the first network device has received the second data.

[0063] In a ninth aspect, a communication apparatus is provided, which is configured to perform the method in any one of the first aspect to the fourth aspect and any possible implementation thereof. Specifically, the apparatus can comprise units and / or modules for performing the method in any one of the first aspect to the fourth aspect and any possible implementation thereof, such as a processing unit and / or a communication unit.

[0064] In an implementation, the apparatus is a communication device (e.g., a terminal device, or a network device). When the apparatus is a communication device, the communication unit can be a transceiver, or an input / output interface; and the processing unit can be at least one processor. Optionally, the transceiver can be a transceiver circuit. Optionally, the input / output interface can be an input / output circuit.

[0065] In another implementation, the apparatus is a chip, chip system or circuit or communication module for a communication device (e.g., a terminal device, or a network device). When the apparatus is a chip, chip system or circuit for a communication device, the communication unit can be an input / output interface, interface circuit, output circuit, input circuit, pin or related circuit on the chip, chip system or circuit, etc.; and the processing unit can be at least one processor, processing circuit or logic circuit, etc.

[0066] In a tenth aspect, a communication apparatus is provided, which comprises at least one processor configured to cause the apparatus to perform the method in any one of the first aspect to the fourth aspect and any possible implementation thereof.

[0067] Optionally, the at least one processor is configured to execute computer programs or instructions to perform the method in any one of the first aspect to the fourth aspect and any possible implementation thereof.

[0068] Optionally, the apparatus further comprises a memory configured to store the computer programs or instructions.

[0069] Optionally, the at least one processor is coupled with the memory configured to store the computer programs or instructions. The memory can be disposed outside the apparatus.

[0070] Optionally, the apparatus further comprises a communication interface through which the processor reads the instructions on the memory. It can be understood that the communication interface is coupled with the processor, and can be used to input the computer programs or instructions to the processor, or output the information in the processor.

[0071] For the operations of sending, obtaining / receiving, etc. involved, if no special description is made, or if it is not contrary to the actual role or inherent logic in the related description, it can be understood as output, input, etc. operations, or as sending and receiving operations performed by the radio frequency circuit and the antenna, which are not limited in the present application.

[0072] In an implementation, the apparatus is a communication device (e.g., a terminal device, or a network device).

[0073] In another implementation, the apparatus is a chip, chip system or circuit or communication module for a communication device (e.g., a terminal device, or a network device). Optionally, the chip is a Modem chip, also known as a baseband chip, or a system on chip (SoC) chip or system in package (SIP) chip containing a modem core.

[0074] In an eleventh aspect, a computer-readable storage medium is provided, and the computer-readable medium stores a computer program (for example, program code) or instructions thereon, which, when executed on a communication apparatus, cause the communication apparatus to perform the method in any one of the first aspect to the fourth aspect and any possible implementation thereof.

[0075] In a twelfth aspect, a computer program product containing instructions is provided, which, when executed on a computer, cause the computer to perform the method in any one of the first aspect to the fourth aspect and any possible implementation thereof.

[0076] In a thirteenth aspect, a communication system is provided, including a first communication apparatus and a second communication apparatus. The first communication apparatus is configured to perform the method provided in any one of the implementations of the first aspect, and the second communication apparatus is configured to perform the method provided in any one of the implementations of the second aspect. BRIEF DESCRIPTION OF DRAWINGS

[0077] FIG. 1 is a schematic diagram of a communication architecture suitable for embodiments of the present application.

[0078] FIG. 2 is a schematic diagram of a base station CU-DU separation architecture suitable for embodiments of the present application.

[0079] FIG. 3 is a schematic diagram of a 5G XR communication architecture suitable for embodiments of the present application.

[0080] FIG. 4 is a schematic diagram of a video encoding model suitable for embodiments of the present application.

[0081] FIG. 5 is a schematic diagram of PDCP packet loss suitable for embodiments of the present application.

[0082] FIG. 6 is a schematic diagram of PDCP reordering suitable for embodiments of the present application.

[0083] FIG. 7 is a schematic diagram of an increase in downlink waiting latency after handover suitable for embodiments of the present application.

[0084] FIG. 8 is a schematic diagram of an increase in uplink waiting latency after handover suitable for embodiments of the present application.

[0085] FIG. 9 is a schematic diagram of a communication method 900 provided by embodiments of the present application.

[0086] FIG. 10 is a schematic diagram of another communication method 1000 provided by embodiments of the present application.

[0087] FIG. 11 is a schematic diagram of yet another communication method 1100 provided by embodiments of the present application.

[0088] FIG. 12 is a schematic diagram of a communication apparatus 1200 provided by embodiments of the present application.

[0089] FIG. 13 is a schematic diagram of another communication apparatus 1300 provided by the embodiments of the present application.

[0090] FIG. 14 is a schematic diagram of a chip system 1400 provided by the embodiments of the present application. DETAILED DESCRIPTION

[0091] The technical solutions in the present application will be described below with reference to the accompanying drawings.

[0092] Before introducing the solutions of the present application, the following points are explained.

[0093] (1) In the present application, "indication" can include direct indication, indirect indication, explicit indication, implicit indication, etc. When describing that certain indication information indicates A, it can be understood that the indication information carries A, carries an identifier of A, carries B having a correlation relationship with A, carries an identifier of B having a correlation relationship with A, etc. In other words, if the receiving side of certain indication information can determine A according to the indication information, it can be described that the indication information indicates A, and the specific determination manner is not limited. When it is understood that the indication information carries A, "indication" can be replaced by "includes", and at this time, similar to the expression "sending / receiving indication information, the indication information indicates A", it can be replaced by "sending / receiving A".

[0094] In the present application, the information indicated by the indication information is referred to as to-be-indicated information. In the specific implementation process, there are many ways to indicate the to-be-indicated information, for example but not limited to, the to-be-indicated information can be directly indicated, such as the to-be-indicated information itself or an index of the to-be-indicated information, etc. The to-be-indicated information can also be indirectly indicated by indicating other information, where the other information has a correlation relationship with the to-be-indicated information. The to-be-indicated information can also be only indicated in part, and the other part of the to-be-indicated information is known or agreed in advance. For example, the indication of specific information can also be achieved by means of the arrangement order of each information agreed in advance (for example, the protocol stipulates), thereby reducing the indication overhead to a certain extent. In addition, the to-be-indicated information can be sent as a whole, or can be sent separately into multiple sub-information, and the sending period and / or sending occasion of these sub-information can be the same or different.

[0095] (2) In this application, the expression " / " is used to represent the relationship of "or" between the objects associated in front and back; for example, A / B can represent: A or B. The expression "and / or" is used to represent the relationship of both and or or between the objects associated in front and back; for example, A and / or B can represent the following cases: A exists alone, B exists alone, A and B exist together, wherein A, B can be single or multiple. "At least one of the following" or similar expressions are used to represent any combination of the listed items; for example, at least one of A, B and (or) C can represent the following cases: A exists alone, B exists alone, C exists alone, A and B exist together, B and C exist together, A and C exist together, A, B and C exist together, wherein A, B, C can be single or multiple.

[0096] (3) In this application, "send" and "receive" represent the direction of signal transmission. For example, "sending information to XX" can be understood as the destination of the information being XX, which can include direct transmission through the air interface, or indirect transmission through the air interface by other units or modules. "Receiving information from YY" can be understood as the source of the information being YY, which can include direct reception from YY through the air interface, or indirect reception from YY through the air interface from other units or modules. "Send" can also be understood as the "output" of the chip interface, and "receive" can also be understood as the "input" of the chip interface. In other words, sending and receiving can be between devices, such as between network devices and terminal devices, or within a device, such as between components, modules, chips, software modules or hardware modules within a device through a bus, wire or interface.

[0097] (4) In various embodiments of the present application, the terms and / or descriptions of different embodiments are consistent and can be mutually referenced if there is no special description and logical conflict. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0098] (5) In this application, "first", "second" are only for convenience of description, used to distinguish the objects, and not used to limit the scope of the embodiments of the present application. It is not used to describe the order or sequence of the characteristics. It should be understood that the objects thus described can be interchanged under appropriate circumstances in order to describe solutions other than the embodiments of the present application.

[0099] (6) In this application, "predefined" can mean standard protocol predefined, or can also mean pre-agreed or pre-negotiated between devices. Among them, "protocol" can refer to standard protocols in the communication field, which can include fourth generation (4 th generation, 4G) network, fifth generation (5th In this application, the new radio (NR) protocol, the 5.5G network protocol, the future communication network protocol, and the related protocol applied in the future communication system are not limited.

[0100] (7) In this application, the words such as "exemplarily", "for example" and the like are used to represent examples, illustrations or descriptions. Any embodiment or design scheme described as "example" in this application should not be interpreted as more preferred or more advantageous than other embodiments or design schemes. Rather, the word "example" is used to present the concept in a specific way. In the embodiments of this application, "of", "corresponding" and "corresponding" are sometimes mixed. It should be pointed out that when the difference is not emphasized, the meanings expressed are consistent.

[0101] First, introduce the communication system applicable to this application.

[0102] The technical solutions provided in this application can be applied to various communication systems, such as: 5th generation (5G) or new radio (NR) system, long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD) system, etc. The technical solutions provided in this application can also be applied to future communication systems, such as future communication network mobile communication systems. The technical solutions provided in this application can also be applied to device to device (D2D) communication, vehicle-to-everything (V2X) communication, machine to machine (M2M) communication, machine type communication (MTC), and internet of things (IoT) communication system. The technical solutions provided in this application can also be applied to non-terrestrial network (NTN) systems such as inter-satellite communication and satellite communication.

[0103] As an example, a satellite communication system includes a satellite base station and a terminal device. The satellite base station provides communication services for the terminal device. The satellite base station can also communicate with a base station. The satellite can act as a base station and also as a terminal device. The satellite can refer to a drone, a hot air balloon, a low earth orbit satellite, a medium earth orbit satellite, a high earth orbit satellite, etc. The satellite can also refer to a non-ground base station or a non-ground device, etc.

[0104] As an example, V2X communication can include vehicle-to-vehicle (V2V) communication, vehicle-to-infrastructure (V2I) communication, vehicle-to-pedestrian (V2P) communication, vehicle-to-network (V2N) communication, etc.

[0105] A device in a communication system can send a signal to another device or receive a signal from another device. The signal can include information, signaling, or data, etc. The device can also be replaced by an entity, a network entity, a communication device, a communication module, a node, a communication node, etc. The device is taken as an example for description in embodiments of the present application.

[0106] The terminal device in the embodiments of the present application can be a device or module with corresponding communication functions for accessing the above-mentioned communication system. The terminal device can include various devices with wireless communication functions, which can be used to connect people, things, machines, etc. The terminal device can be widely used in various scenarios, such as cellular communication, D2D, V2X, end-to-end, M2M, MTC, IoT, virtual reality (VR), augmented reality (AR), extended reality (XR), industrial control, autonomous driving, remote medical treatment, smart power grid, smart furniture, smart office, smart wear, smart traffic, smart city UAV, robot, remote sensing, passive sensing, positioning, navigation and tracking, autonomous delivery, etc. The terminal device can be a terminal in any of the above scenarios, such as an MTC terminal, an IoT terminal, etc. The terminal device can be a user equipment (UE) of the 3rd generation partnership project (3GPP) standard, a terminal, a fixed device, a mobile station device or a mobile device, a subscriber unit, a handset, a vehicle-mounted device, a wearable device, a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a wireless data card, a personal digital assistant (PDA), a computer, a tablet computer, a notebook computer, a wireless modem, a handset, a laptop computer, a computer with wireless transceiver function, a smart book, a vehicle, a satellite, a global positioning system (GPS) device, a target tracking device, an aircraft (such as a drone, a helicopter, a multi-helicopter, a four-helicopter, or an airplane, etc.), a ship, a remote control device, a smart home device, an industrial device, a transport vehicle with wireless communication function, a communication module, a road side unit (RSU) with terminal function, or a device built-in in the above-mentioned device (such as a communication module, a modem or a chip in the above-mentioned device, etc.), or other processing devices connected to the wireless modem.

[0107] By way of example and not limitation, in embodiments of the present application, the terminal device can also be a wearable device. The wearable device can also be referred to as a wearable smart device, which is a general term for devices that are designed and developed by applying wearable technology to daily wear, such as glasses, gloves, watches, clothing, and shoes. The wearable device is a portable device that is directly worn on the body or integrated into the clothes or accessories of the user. The wearable device is not only a hardware device, but also has powerful functions through software support and data interaction and cloud interaction. The general wearable smart device includes a full function, a large size, and can realize complete or partial functions without relying on a smart phone, such as a smart watch or smart glasses, and focuses on a certain application function and needs to cooperate with other devices such as a smart phone, such as various smart wristbands and smart jewelry for monitoring vital signs.

[0108] It should be understood that in some scenarios, the UE can also be used to act as a base station. For example, the UE can act as a scheduling entity that provides sidelink signals between UEs in V2X, D2D, or the like scenarios.

[0109] In embodiments of the present application, the device for implementing the function of the terminal device, i.e., the terminal device, can be a terminal device or a device capable of supporting the terminal device to implement the function, such as a chip system or a chip or a circuit or a communication module (i.e., a communication module that performs a communication function), which can be installed in the terminal device. In embodiments of the present application, the chip system can be composed of a chip or can include a chip and other discrete devices. In addition, the device can also be configured with program instructions for performing corresponding communication functions.

[0110] The network device in the embodiments of the present application can be a device or module with corresponding communication function. The network device can be a device for communicating with a terminal device, and the network device can also be referred to as an access network device or a radio access network device, for example, the network device can be a base station. The network device in the embodiments of the present application can refer to a radio access network (RAN) node (or device) for accessing a terminal device to a wireless network. The base station can broadly cover various names in the following or be replaced by the following names, such as: node B (NodeB), evolved node B (eNB), next generation node B (gNB), relay station, access point, transmitting and receiving point (TRP), transmission point, primary station, secondary station, multi-standard radio (MSR) node, home base station, network controller, access node, wireless node, access point (AP), transmission node, transceiver node, baseband unit (BBU), remote radio unit (RRU), active antenna unit (AAU), remote radio head (RRH), central unit (CU), distributed unit (DU), positioning node, etc. The base station can be a macro base station, a micro base station, a relay node, a donor node or the like, or a combination thereof. The base station can also refer to a communication module, modem or chip for being arranged in the foregoing device or apparatus. The base station can also be a mobile switching center and a device assuming a base station function in D2D, V2X, M2M communication, a network side device in a future communication network, a device assuming a base station function in a future communication system, etc. The base station can support networks of the same or different access technologies. The embodiments of the present application do not limit the specific technology and specific device form of the network device.

[0111] The base station can be fixed or mobile. For example, a helicopter or a drone can be configured to act as a mobile base station, and one or more cells can move according to the location of the mobile base station. In other examples, the helicopter or the drone can be configured to act as a device communicating with another base station.

[0112] In some deployments, the network device mentioned in embodiments of the present application can be a device including a CU, or a DU, or a device including a CU and a DU, or a control plane CU node (central unit-control plane (CU-CP)) and a user plane CU node (central unit-user plane (CU-UP)), and a DU node.

[0113] In some deployments, a plurality of RAN nodes cooperate to assist a terminal device to implement wireless access, and different RAN nodes respectively implement part of the functions of a base station. For example, the RAN node can be a CU, a DU, a CU-CP, a CU-UP, or a radio unit (RU), etc. The CU and the DU can be separately arranged, or can also be included in the same network element, such as a BBU. The RU can be included in a radio frequency device or a radio frequency unit, such as an RRU, an AAU, or an RRH.

[0114] In different systems, the CU (or CU-CP and CU-UP), DU, or RU can also have different names, but those skilled in the art can understand their meanings. For example, the radio access network can also be an open radio access network (O-RAN) architecture, in which the CU can also be referred to as an open CU (O-CU), the DU can also be referred to as an open DU (O-DU), the CU-CP can also be referred to as an open CU-CP (O-CU-CP), the CU-UP can also be referred to as an open CU-UP (O-CU-UP), and the RU can also be referred to as an open RU (O-RU). Any of the CU (or CU-CP, CU-UP), DU, and RU in the present application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0115] In embodiments of the present application, the apparatus for implementing the function of the network device can be a network device, or an apparatus capable of supporting the network device to implement the function, such as a chip system or a chip or a circuit or a communication module (i.e., a communication module performing a communication function), which can be installed in the network device. In embodiments of the present application, the chip system can be composed of a chip, or can include a chip and other discrete devices. In addition, program instructions for performing corresponding communication functions can also be configured in the apparatus. In embodiments of the present application, only the apparatus for implementing the function of the network device is taken as an example of the network device, and the scheme of embodiments of the present application is not limited.

[0116] The network device and the terminal device can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; can also be deployed on water; and can also be deployed on airplanes, balloons and satellites in the air. The scene in which the network device and the terminal device are located is not limited in the embodiments of the present application.

[0117] Referring to FIG. 1, FIG. 1 is a schematic diagram of a communication architecture suitable for the embodiments of the present application. In the present application, the embodiments of the present application are described by taking a 5G base station as an example. As shown in FIG. 1, in the 5G system, the base station is referred to as gNB / ng-eNB, mainly including radio resource control (RRC), service data adaptation protocol (SDAP), packet data convergence protocol (PDCP), radio link control (RLC), media access control (MAC) and physical layer (PHY), which can be collectively represented by gNB, and the gNBs are connected through an Xn interface. The gNB and the 5G core network are connected through an NG interface. In some deployments, the gNB can be composed of a CU and a DU, that is, the functions of the base station in the original access network are split, part of the functions of the base station are deployed in a CU, and the remaining functions are deployed in a DU, multiple DUs share one CU, which can save cost and facilitate network expansion. The split of the CU and the DU can be according to the protocol stack, and one possible way is to deploy the RRC, SDAP and PDCP layers in the CU, and the remaining RLC, MAC and PHY in the DU. The CU and the DU are connected through an F1 interface. The CU represents the gNB to connect with the core network through the NG interface, the CU represents the gNB to connect with other gNBs through the Xn interface, and the CU can also represent the gNB to connect with other eNBs through the X2 interface to perform a dual connection operation.

[0118] Referring to FIG. 2, FIG. 2 is a schematic diagram of a base station CU-DU separation architecture suitable for embodiments of the present application. As shown in FIG. 2, the CU can also be divided into a control plane (CU-CP) and a user plane (CU-UP). The CU-CP is responsible for control plane functions, mainly including RRC and the PDCP corresponding to the control plane, i.e., PDCP-C. The PDCP-C is mainly responsible for encryption and decryption of control plane data, integrity protection, data transmission, etc. The CU-UP is responsible for user plane functions, mainly including SDAP and the PDCP corresponding to the user plane, i.e., PDCP-U. The SDAP is mainly responsible for processing data of the core network and mapping the flow to the bearer. The PDCP-U is mainly responsible for encryption and decryption of the data plane, integrity protection, header compression, sequence number maintenance, data transmission, etc. The CU-CP and the CU-UP are connected through an E1 interface. The CU-CP and the CU-UP are connected with the core network through an NG interface. The control plane of the CU, i.e., F1-C, is connected with the DU through an F1 interface. The user plane of the CU, i.e., F1-U, is connected with the DU through an F1 interface. Of course, there is also a possible implementation that the PDCP-C is also in the CU-UP.

[0119] Referring to FIG. 3, FIG. 3 is a schematic diagram of a 5G XR communication architecture suitable for embodiments of the present application. Exemplarily, in FIG. 3, for a service, the following behaviors, data is generated by an application server, forwarded through a data network (Data Network, DN), sent to the core network through an N6 interface, the core network transmits data to the base station through an N3 interface, and the base station sends data to the UE through a Uu air interface. In addition, for sidelink (SL) communication, communication is carried out between user communication devices (e.g., XR devices) and user communication devices (e.g., XR devices).

[0120] It can be understood that FIG. 3 is only an example and is not a limitation on the application scenarios to which the present application applies. Among them, the core network device refers to a device in the core network (CN) that provides service support for the terminal. At present, some examples of core network devices are: access and mobility management function (AMF) entity, session management function (SMF) entity, user plane function (UPF) entity, and the like, which are not listed one by one here. Among them, the AMF entity can be responsible for access management and mobility management of the terminal; the SMF entity can be responsible for session management, such as session establishment of a user; and the UPF entity can be a functional entity of the user plane, mainly responsible for connecting external networks. It should be noted that the entity in the present application can also be referred to as a network element or a functional entity, for example, the AMF entity can also be referred to as an AMF network element or an AMF functional entity, and for example, the SMF entity can also be referred to as an SMF network element or an SMF functional entity, and the like.

[0121] For the convenience of understanding the embodiments of the present application, the terms involved in the present application are briefly explained.

[0122] 1. XR service:

[0123] XR can refer to an environment combining reality and virtuality generated by computing technology and wearable devices, as well as human-computer interaction, which specifically includes the following typical forms: VR, AR, and mixed reality (MR). XR is one of the 5G multimedia applications that the industry focuses on. 3GPP Rel-17 has modeled and analyzed the service characteristics of XR. Typically, XR services periodically generate data frames according to a certain frame rate. Taking an AR service with a frame rate of 60fps as an example, 60 video images are generated per second, and a video frame occurs approximately every 16.66ms. A video frame can be transmitted by multiple data packets, which can be divided into one or more protocol data unit sets (PDU sets).

[0124] The XR service usually has a higher latency requirement. Taking the uplink AR service as an example, its typical packet delay budget (PDB) is 30 ms, that is, the upper limit of the transmission delay between the data packet arriving at the UE access layer and the data packet arriving at the N6 interface of the UPF is 30 ms. If the data packet is not successfully transmitted within the PDB required time, it is considered that the data packet has timed out and lost its effect. Alternatively, the packet set delay budget (PSDB) may also be considered in the XR service, which has a similar meaning to PDB, and defines an upper limit of the transmission delay of a group of data packets (a PDU set). For uplink, it refers to the upper limit of the time from the arrival of the first data packet in the PDU set at the UE access layer to the arrival of the last data packet at the N6 interface of the UPF, and for downlink, it is the opposite. The network should try to complete data scheduling and transmission within the delay budget to avoid data timeout and thus affect the service experience.

[0125] 2. PDU set importance (PSI):

[0126] In the XR service, different degrees of importance of data may occur in the same data stream. This is caused by the coding method of the application. Taking the XR video service as an example, the application can use inter-frame prediction coding when coding data, thereby compressing the amount of data to be transmitted. Simply put, this type of coding method is to take advantage of the fact that most of the content in adjacent video frames does not change, and only transmit the data of the part that changes, and the part that does not change is directly used the previous data, for example, in a live video, the background usually does not change, so only the first frame of video needs to transmit complete data, and the subsequent video frames only need to transmit the data of the foreground character change, and the background data does not need to be transmitted again, and the receiver player can directly use the background data of the first frame to generate the picture of the subsequent video frames.

[0127] Among them, one of the classic encoding methods is group of picture (GOP) based encoding. In this encoding method, a GOP contains several consecutive video frames, of which the first frame is called an intra-coded picture (I) frame, which uses intra coding and contains complete image information and can be independently encoded and decoded. The remaining frames are called predictive-coded pictures (P) frames, which use predictive coding and only contain partial image information and need to rely on previous frames for encoding and decoding. In another similar encoding method, a video frame is divided into multiple video slices, some of which use intra coding and some of which use predictive coding, and are called I-slices and P-slices, respectively. The encoding and decoding of P-slices in the latter frames need to rely on the I-slices at the corresponding positions in the previous frames.

[0128] Referring to FIG. 4, FIG. 4 is a schematic diagram of a video encoding model suitable for embodiments of the present application, and the dependency relationship of the above-mentioned two video frame encoding and decoding is shown in FIG. 4.

[0129] It should be noted that one frame or one slice may correspond to one or more PDU sets when transmitted in a wireless network. The encoding model of XR video reflects the unequal importance of data. Since the correct decoding of P frames / P-slices depends on the correct decoding of I frames / I-slices, the I frame / I-slice data has higher importance in the data transmission process, and the reliable transmission of I frames / I-slices should be prioritized in network congestion to ensure service experience.

[0130] In order to distinguish the unequal importance of different data in the same data stream, 3GPP proposes the concept of PDU set importance (PSI). According to the provisions in 3GPP protocol 23.700, different importance levels of PDU sets can be included in a QoS flow of an XR service, and identified by PSI. For example, in an XR video stream, the PSI of the PDU set corresponding to the I frame / I-slice can be stronger than the PSI of the PDU set corresponding to the P frame / P-slice, because the encoding and decoding of the P frame / P-slice depends on the I frame / I-slice, and therefore the I frame / I-slice data has higher importance. For downlink data transmission, the PSI corresponding to each PDU set is provided by the CN to the RAN, and for uplink data transmission, the PSI corresponding to each PDU set is identified by the terminal device itself.

[0131] 3. PDCP discard:

[0132] Referring to FIG. 5, which is a PDCP packet loss diagram applicable to embodiments of the present application. In a wireless network, the PDCP layer at the transmitting side performs packet loss operation. Specifically, when the PDCP layer receives a PDCP service data unit (SDU) from an upper layer, it starts a discard timer for the PDCP SDU. When the discard timer expires, the PDCP layer discards the PDCP SDU and the corresponding PDCP PDUs, which are the processed data of the PDCP SDU, including encryption, compression, adding protocol header, etc. If the PDCP PDUs have already been delivered to a lower layer (e.g., RLC layer), the lower layer is notified of the packet loss.

[0133] For the PDU set concept introduced for XR services, the above PDCP packet loss mechanism can be enhanced, i.e., PDU set discard can be enabled. Specifically, when the PDCP layer receives a PDCP SDU from an upper layer, it still starts a discard timer, but when the discard timer for a certain PDCP SDU expires, the PDCP layer discards all PDCP SDUs in the PDU set to which the PDCP SDU belongs and their corresponding PDCP PDUs. Similarly, if there are PDCP PDUs that have already been delivered to a lower layer, the lower layer is notified.

[0134] In XR services, a function of importance-based packet loss is also introduced. Specifically, when network congestion occurs, the network can discard some data packets with lower importance (i.e., larger PSI) in advance. For example, for uplink, the network can instruct the UE to perform importance-based packet loss. After receiving the instruction, when the PDCP layer receives a PDCP SDU from an upper layer, if it finds that the PDCP SDU belongs to a PDU set with lower importance, it starts a discard timer with a shorter duration (e.g., in an extreme case, the duration of the short timer is 0) for the PDCP SDU, so that data with lower importance stays in the buffer for a shorter time, has fewer transmission opportunities, and is more likely to be discarded, thereby alleviating network congestion. The network can also perform similar operations on downlink data.

[0135] Further, importance-based packet loss can also be combined with PDU set discard, i.e., when the network or the UE discards a data packet with lower importance, all data packets in the PDU set to which the data packet belongs are also discarded.

[0136] 4. Inter-station handover:

[0137] To support terminal mobility, the terminal can switch the connection between different base stations. During the inter-station handover process, the network needs to maintain the lossless data transmission, and in order to achieve this purpose, the network and the terminal after handover determine whether there is data packet that needs to be retransmitted through PDCP status report. For downlink transmission, after handover is completed, the terminal sends a PDCP status report to the target base station, which indicates the PDCP sequence number of the data packet that the terminal has not received (is waiting to receive) at present, and then the target base station should transmit these data packets to the terminal. Correspondingly, for uplink transmission, after handover is completed, the target base station sends a PDCP status report to the terminal, which indicates the PDCP sequence number of the data packet that the target base station is currently waiting to receive, so that the terminal transmits these data packets to the target station.

[0138] Referring to FIG. 6, FIG. 6 is a PDCP reordering diagram suitable for embodiments of the present application.

[0139] A possible implementation, when the PDCP entity on the sending side discards a data packet, the PDCP entity on the receiving side may have a receiving hole because it does not receive the data packet. For example, as shown in FIG. 6, the PDCP entity on the receiving side receives data packets 1 and 2, and normally submits them to the upper layer. Then, the PDCP on the receiving side receives data packets 4 and 5, and since data packet 3 is not received, a hole is generated. At this time, the PDCP on the receiving side does not immediately submit data packet 4 to the upper layer, but starts a reordering timer first. During the running of the timer, if the PDCP on the receiving side receives data packet 3, it can submit data packets 3, 4 and 5 to the upper layer, otherwise, it submits data packets 4 and 5 to the upper layer only after the timer expires.

[0140] If data packet 3 has been discarded by the PDCP entity on the sending side, it is possible that the PDCP on the receiving side has no opportunity to receive data packet 3, but the PDCP on the receiving side still waits until the reordering timer expires, which causes data packets 4 and 5 that have been received to be delayed in submission. Especially after the XR service supports packet loss based on PDU set and packet loss based on PSI, the PDCP entity on the sending side will discard more data packets more frequently, which will cause the receiving side to generate more holes and increase the waiting delay of data packets that are not discarded.

[0141] As an example, after packet loss, the sending side PDCP entity can inform the receiving side PDCP of the packet loss information through a sequence number gap report or a packet data convergence protocol sequence number gap report (PDCP SN gap report), for example, the PDCP SN of the discarded data packet is informed to the receiving side PDCP, so that the receiving side PDCP entity does not need to continue to wait for the discarded packet. For example, in the above example, the sending side PDCP can tell the receiving side PDCP that data packet 3 has been discarded, and after receiving this information, the receiving side PDCP can directly stop the reordering timer and submit data packets 4 and 5 upwards, and no longer wait to receive data packet 3. In this way, the delay problem caused by the hole generated by the receiving side due to the packet loss of the sending side can be avoided.

[0142] The triggering condition of the PDCP SN gap report is PDCP packet loss. For the inter-station handover scenario, packet loss can occur at the source station, and the target station does not know about the packet loss that occurs at the source station, which can cause the receiving side to continue to wait for the discarded data packet after handover, causing additional waiting delay.

[0143] Referring to FIG. 7, FIG. 7 is a schematic diagram of an increase in downlink waiting delay after handover suitable for embodiments of the present application. For downlink transmission, if packet loss occurs before handover, the source station can generate a PDCP SN gap report to inform the terminal of the packet loss, for example, the source station can inform the terminal that data packet x has been discarded. However, since the transmission of the PDCP SN gap report takes time, the terminal can not have received the gap report before handover. After the terminal switches to the target station, since the terminal does not receive the gap report from the source station, the terminal does not know that data packet x has been discarded, and the terminal continues to wait for data packet x. However, since data packet x has actually been discarded at the source station, the terminal can only wait until the reordering timer expires, causing an increase in the delay of data after data packet x.

[0144] Referring to FIG. 8, FIG. 8 is a schematic diagram of an increase in uplink waiting delay after handover suitable for embodiments of the present application. For uplink transmission, if packet loss occurs before handover, the terminal can generate a PDCP SN gap report to inform the source station of the packet loss, for example, the terminal can inform the target station that data packet x has been discarded. Regardless of whether the source station receives the gap report, after handover is completed, the target station does not know that data packet x has been discarded, and the target station can continue to wait for data packet x, causing an increase in the waiting delay of subsequent data.

[0145] Therefore, the application provides a communication method and a communication device, which can reduce the waiting delay by indicating the discarded data before the handover to the receiving device by the sending device after the handover.

[0146] The method provided by the embodiments of the application will be described in detail below with reference to the drawings. The embodiments provided by the application can be applied to the scenario shown in the above-mentioned figures, without limitation.

[0147] Referring to FIG. 9, FIG. 9 is a schematic diagram of a communication method 900 provided by an embodiment of the application, as an example. For ease of description, a terminal device and a network device are exemplarily described below. The terminal device can be replaced by a component (for example, a chip or a chip system or a circuit or a communication module) of the terminal device, and the network device can be replaced by a component (for example, a chip or a chip system or a circuit or a communication module) of the network device. In addition, the steps described below executed by a single execution subject can also be divided into execution by multiple execution subjects, which can be logically and / or physically separated. The method 900 shown in FIG. 9 can include the following steps.

[0148] The method 900 includes steps 940 and 950, and optionally, the method 900 includes steps 910, 920 and 930.

[0149] 910, the second network device sends data forwarding, and accordingly, the first network device receives the data forwarding.

[0150] As an example, in the embodiments of the application, the first network device can also be referred to as a target station or a target base station (target gNB), and the first network device can be a network device to which the terminal device is connected after the inter-station handover.

[0151] As an example, in the embodiments of the application, the second network device can also be referred to as a source station or a source base station (source gNB), and the second network device can be a network device to which the terminal device is connected before the inter-station handover.

[0152] As an example, the data forwarding can include user plane data, such as audio data, video stream and the like, and can also include control plane data, such as handover request, resource allocation and the like, to ensure the smooth handover and the continuity of user service during the inter-station handover.

[0153] It should be understood that in the embodiments of the application, the data can correspond to the SN, and the data can be replaced by a PDCP PDU, a PDCP SDU, a data packet or a PDU set, without limitation in the embodiments of the application.

[0154] Optionally, the forwarding data is a PDCP SDU, and the SN corresponds to the PDCP SDU.

[0155] For example, the second network device sends the forwarding data to the first network device, the forwarding data corresponding to SNs 5, 6, and 7.

[0156] 920, the second network device sends SN status transfer information, and the first network device receives the SN status transfer information.

[0157] The SN status transfer information can be used to mark the status of the data corresponding to the SN. The SN status transfer information can also be referred to as sequence number status transfer information or sequence number status indication information, and the naming does not limit the protection scope of the embodiments of the present application.

[0158] For example, the SN status transfer information can be an SN status message transmitted by the second network device to the first network device during the handover process. The SN status transfer information can indicate a next PDCP SN to the first network device, that is, the SN that should be allocated by the first network device to a next new PDCP SDU, or the SN that should be allocated by the first network device to a next data that has not been associated with an SN.

[0159] Optionally, the new PDCP SDU is from the second network device, or the new PDCP SDU is from a core network.

[0160] It should be understood that the step 920 can be performed before, after or at the same time as the step 910, and the embodiments of the present application do not limit the execution order of the step 910 and the step 920.

[0161] 940, the first network device determines first information, the first information indicating first data discarded by the second network device.

[0162] The first information can also be referred to as a packet loss information, a packet loss report, a hole report, or a PDCP SN gap report.

[0163] Specifically, the determination of the first information can be implemented by the following steps:

[0164] Step 1, determining a first index, the first index being a minimum index corresponding to data forwarded by the second network device to the first network device.

[0165] The data forwarded by the second network device to the first network device can include the forwarding data in the step 910.

[0166] As an example, the SNs of the forwarded data in step 910 are 5, 6, and 7, and the state transfer information in step 920 indicates that the next sequence number is 9. In this case, the first index can be 5, and the second index can be 9.

[0167] Step 2: determining a second index, which is the next index allocated by the first network device to the data to be sent to the terminal device.

[0168] The next index allocated by the first network device to the data to be sent to the terminal device can be indicated by the state transfer information in step 920.

[0169] As an example, the state transfer information in step 920 indicates that the next sequence number is 9. In this case, the next index allocated by the first network device to the data to be sent to the terminal device can be 9, and the second index can be 9.

[0170] It should be understood that step 2 can be performed before, after, or at the same time as step 1, and the execution order of step 1 and step 2 is not limited by the embodiments of the present application.

[0171] Step 3: determining an index corresponding to the first data, which is greater than the first index and less than the second index.

[0172] The first data can be data discarded by the second network device, or in other words, data discarded before the inter-station handover.

[0173] Specifically, the first network device checks a gap (PDCP SN gap) between the first index and the second index in the forwarded data. The gap can be understood as a packet loss of the second network device, or in other words, a packet loss before the handover. The first data can include all or part of the data corresponding to the gap.

[0174] As an example, the SNs of the forwarded data in step 910 are 5, 6, and 7, and the state transfer information in step 920 indicates that the next sequence number is 10. In this case, the first index can be 5, the second index can be 10, and the gap between the first index and the second index in the forwarded data is 8 and 9. The first data can include all or part of the data corresponding to SNs 8 and 9.

[0175] As another example, the SNs of the forwarded data in step 910 are 3, 4, and 7, and the state transfer information in step 920 indicates that the next sequence number is 9. In this case, the first index can be 3, the second index can be 9, and the gap between the first index and the second index in the forwarded data is 5, 6, and 8. The first data can include all or part of the data corresponding to SNs 5, 6, and 8.

[0176] In the embodiments of the present application, the first network device can obtain the index corresponding to the discarded first data of the second network device through the data forwarded by the second network device and the next index allocated for the data sent to the terminal device, without the second network device indicating to the first network device with additional signaling overhead.

[0177] The index, such as the minimum index, can also be replaced by other parameters, such as the maximum index and the number of SNs.

[0178] 950, the first network device sends the first information to the terminal device, and correspondingly, the terminal device receives the first information from the first network device, the first information being used to make the terminal device consider that the first data has been discarded.

[0179] Optionally, the first information can specifically indicate the first data in one or more of the following Form 1 to Form 3:

[0180] Form 1, the first information indicates the first data through SNs.

[0181] As an example, the SNs corresponding to the first data are 4, 5, 8 and 9, and the first information can directly indicate SN 4, SN 5, SN 8 and SN 9.

[0182] Form 2, the first information indicates the first data through the SN corresponding to the first data in the first data and a bitmap.

[0183] The bitmap corresponds to a number of SNs after the first data in the first data, each bit in the bitmap corresponds to an SN, and if a bit in the bitmap is a first value (0 or 1), it means that the data packet corresponding to the SN corresponding to the bit has been discarded.

[0184] As an example, the SNs corresponding to the first data are 4, 5, 8 and 9, and the first information can indicate SN 4 and contain a bitmap (10011) at the same time, wherein the "1" respectively corresponds to SN 5, SN 8 and SN 9.

[0185] Form 3, the first information indicates the first data through a number of SNs corresponding to a number of data in the first data and the corresponding length L.

[0186] L represents that the data packets corresponding to the L SNs after the SN are also discarded, and the L SNs after the SN can contain or not contain the SN.

[0187] As an example, assuming that the L SNs after the SN contain the SN, the SNs corresponding to the first data are 4, 5, 8, and 9, the first information can indicate SN 4 and L1=2 and SN 8 and L2=2, indicating that the first data includes two data (SN 4, SN 5) starting from SN 4, and 2 data (SN 8, SN 9) starting from SN 8.

[0188] Optionally, before the first network device sends the first information, if new packet loss occurs in the first network device itself, the first data can also include the data discarded by the first network device, and the first information is used to indicate the terminal device.

[0189] As an example, the first information is used to make the terminal device consider that the first data has been discarded, so that after the terminal device receives the first information, the terminal device can not continue to wait for the first data, or in other words, the terminal device can stop detecting or stop receiving the first data, or in other words, the terminal device can stop or not enable a timer for waiting for the first data.

[0190] In the embodiment of the application, the first network device can indicate to the terminal device the first data discarded by the second network device connected with the terminal device before the inter-station handover, so that the terminal device can consider that the first data has been discarded, so that the terminal device can not continue to wait for the first data discarded before the handover, avoiding the influence of the packet loss occurring before the handover on the waiting delay of the data after the handover. The terminal device can update the receiving window in time, achieving the effect of reducing the waiting delay of the terminal device.

[0191] Optionally, the method 900 further includes step 930, the terminal device sends third information, and correspondingly, the first network device receives the third information, the third information indicating that the terminal device has not received the first data.

[0192] As an example, the third information can be a PDCP status report of the terminal device, indicating the PDCP sequence number of the data (or in other words, the data not received, the data waiting to be received) not received by the terminal device, and / or the PDCP sequence number of the data received by the terminal device.

[0193] As an example, after the first network device determines the hole existing in the forwarded data, the first network device can receive the third information, the third information indicating that the terminal device has not received the first data. If the first data is indicated as not received in the third information, and the first data is in the hole existing in the forwarded data, the first network device determines and sends the first information to indicate the first data to the terminal device.

[0194] As an example, the data x is located in a hole where the forwarding data exists, and the terminal device has timed out a timer for waiting for the data x before sending the third information, so the terminal device does not continue to wait for the data x, and the third information does not indicate that the data x is not received. Since the first data needs to be indicated as not received in the third information, the first data indicated by the first information does not include the data x.

[0195] In the embodiments of the present application, the terminal device indicates to the first network device that the first data is not received, which means that the terminal device is still waiting to receive the first data. That is, the first network device indicates to the terminal device the first data discarded by the second network device through the first information only after determining that the terminal device is still waiting to receive the first data, thereby preventing the first network device from indicating unnecessary data in the first information and avoiding waste of indication overhead.

[0196] Optionally, before the inter-station handover, the second network device sends fourth information, and correspondingly, the terminal device receives the fourth information, which indicates the second data discarded by the second network device.

[0197] Further, the third information also indicates that the terminal device has received the second data.

[0198] As an example, the terminal device obtains that the second data is discarded by the second network device before the handover, so after the handover, even if the terminal device actually does not receive the second data, the terminal device can indicate that the second data is received through the third information to the first network device, or the terminal device can not indicate that the second data is not received in the third information to the first network device.

[0199] In combination with the embodiments described above, since the third information does not indicate that the terminal device does not receive the second data, the first information sent by the first network device indicates the first data, and the intersection of the first data and the second data is empty, that is, the second data is not indicated in the first information.

[0200] In the embodiments of the present application, the terminal device knows that the second data is discarded by the second network device, so the terminal device does not wait for the second data. The terminal device indicates to the first network device that the second data is received, so that the first network device considers that the terminal device has received the second data, and the first network device does not indicate the second data in the first information, thereby preventing the first network device from indicating unnecessary data in the first information and avoiding waste of indication overhead.

[0201] Referring to FIG. 10, as an example, FIG. 10 is a schematic diagram of another communication method 1000 provided by an embodiment of the present application. In the method 1000 shown in FIG. 10, part of the scheme is the same as or similar to the scheme in the method 900, and therefore reference can be made to and combined with the related scheme in the method 900. The embodiments of the present application will not be repeated here. The embodiments of the present application mainly explain the differences between the method 1000 and the method 900. The method 1000 can include the following steps.

[0202] 1010, the second network device sends second information, and correspondingly, the first network device receives the second information from the second network device, the second information indicating the first data.

[0203] As an example, the second information can also be referred to as packet loss transfer information or PDCP SN gap transfer information, etc. The specific form can refer to the first information described above, and the embodiments of the present application will not be repeated here.

[0204] As an example, the second network device can send the second information to the first network device in the inter-station handover process, for indicating the SN information of the first data discarded by the second network device.

[0205] Optionally, the second information can include the content of the PDCP SN gap report last generated by the second network device, or the content of the PDCP SN gap report generated by the second network device after initiating the handover request, or the content of the PDCP SN gap report generated by the second network device but not yet sent to the terminal device, or the content of the PDCP SN gap report that has not been correctly received by the terminal device.

[0206] As an example, when the terminal device determines the existence of the gap of the forwarded data by itself, it may not be accurate in some scenarios. For example, when the data discarded by the second network device is located before all the forwarded data, the first network device can not be able to determine whether there is a gap according to the minimum index corresponding to the forwarded data.

[0207] For example, the second network device discards the data corresponding to SN 3 and SN 4, the forwarded data sent by the second network device to the first network device corresponds to SN 5, SN 6 and SN 7, and the status transfer information sent by the second network device indicates that the next sequence number is 8. At this time, the first network device can not be able to determine that the second network device discards the data corresponding to SN 3 and SN 4.

[0208] In the embodiments of the present application, the second network device directly indicates the first data discarded before switching to the first network device, so that the first network device can more accurately know the packet loss of the second network device, and the problem that the first network device cannot determine the packet loss information by itself when the discarded data is located before the forwarded data is solved, and the additional waiting delay caused by the terminal device not knowing the packet loss of the second network device after switching and continuing to wait for the discarded packet is avoided.

[0209] 1030, the first network device determines first information, the first information indicating the first data, the first data being data discarded by the second network device.

[0210] For example, the first data can include all or part of the packet loss data of the second network device indicated by the second information.

[0211] Optionally, the first data indicated by the first information is the same as the packet loss data indicated by the second information.

[0212] 1040, the first network device sends the first information to the terminal device, and correspondingly, the terminal device receives the first information from the first network device, the first information being used to make the terminal device consider that the first data has been discarded.

[0213] Optionally, before the first network device sends the first information, if the first network device itself has new packet loss, the first data can also include the data discarded by the first network device, and is indicated to the terminal device through the first information.

[0214] For example, the first information is used to make the terminal device consider that the first data has been discarded, so that after the terminal device receives the first information, the terminal device can not continue to wait for the first data, that is, the terminal device can stop detecting or receiving the first data, or the terminal device can stop or not start a timer for waiting for the first data.

[0215] Optionally, the above method 1000 further includes a step 1020 of sending third information by the terminal device, and correspondingly, the first network device receives the third information, the third information indicating that the terminal device has not received the first data.

[0216] For example, after the first network device receives the second information, the first network device can receive the third information, the third information indicating that the terminal device has not received the first data. If the first data is indicated as not received in the third information, and the first data is in the packet loss data indicated by the second information, the first network device determines and sends the first information to indicate the first data to the terminal device.

[0217] As an example, the second network device discards the data x and indicates to the first network device through the second information, and before the terminal device sends the third information, a timer for waiting for the data x has expired, then the terminal device does not continue to wait for the data x, and further, the third information does not indicate that the data x is not received. Since the first data needs to be indicated as not received in the third information, the first data indicated by the first information does not include the data x.

[0218] In the embodiments of the present application, the terminal device indicates to the first network device that the first data is not received, which means that the terminal device is still waiting to receive the first data. That is, the first network device indicates to the terminal device the first data discarded by the second network device through the first information only after determining that the terminal device is still waiting to receive the first data, thereby preventing the first network device from indicating unnecessary data in the first information and avoiding waste of indication overhead.

[0219] Optionally, before the inter-station handover, the second network device sends fourth information, and correspondingly, the terminal device receives the fourth information, which indicates the second data discarded by the second network device.

[0220] Further, the third information also indicates that the terminal device has received the second data.

[0221] As a possible implementation, under the CU-DU separation architecture, the DU can inform the CU whether the PDCP SN gap report is successfully sent.

[0222] As an example, for downlink, after the PDCP entity located in the CU discards a packet, the SN gap report is generated. The SN gap report itself is a PDCP control PDU, which is delivered to the DU and queued with other normal data packets for air interface transmission.

[0223] Optionally, for RLC AM mode, when the RLC layer determines that a certain data packet has been correctly transmitted to the terminal device, the RLC layer can indicate that the corresponding data of the PDCP layer has been correctly transmitted.

[0224] Specifically, for the CU-DU separation scenario, the DU can indicate to the CU the highest PDCP SN correctly transmitted and the range of PDCP SNs correctly transmitted, so that the PDCP layer knows which SNs correspond to data packets that have been successfully transmitted to the terminal device.

[0225] Optionally, for RLC UM mode, the RLC layer cannot reliably determine whether a certain data packet is correctly transmitted, but can still feed back to the PDCP whether the data packet has been sent out.

[0226] Specifically, for the CU-DU separation scenario, the DU can indicate the highest PDCP SN that has been transmitted to the CU, so that the PDCP layer knows which SN corresponding data packet has been sent.

[0227] Specifically, for the PDCP SN gap report, since it is a PDCP control PDU and does not associate any PDCP SN, the CU can not know whether the gap report is correctly transmitted or has been transmitted through the above information.

[0228] In one possible implementation, when the CU submits the SN gap report to the DU, the control PDU SN is carried to identify the gap report.

[0229] Optionally, the control PDU SN is carried in the PDCP header or the GTP-U header.

[0230] As an example, after the DU correctly transmits the gap report, the DU feeds back the "correctly transmitted control PDU SN" and / or the "correctly transmitted control PDU SN range" to the CU.

[0231] As another example, after the DU transmits the gap report, the DU feeds back the "transmitted control PDU SN" and / or the "transmitted control PDU SN range" to the CU.

[0232] In the embodiments of the present application, under the CU-DU separation architecture, the DU can inform the CU whether the gap report is sent or correctly transmitted, so that the CU determines whether the terminal device knows the packet loss situation.

[0233] For example, in the above method 1000, the CU of the second network device can determine whether the gap report of the second network device is sent to the terminal device through the feedback of the DU, and then determine whether to send the second information to the first network device or determine the data included in the second information.

[0234] In the embodiments of the present application, the second network device determines whether the terminal device has received the gap report before the terminal device switches. If the terminal device has received the gap report, no additional waiting delay will be generated, and the second network device can not send the second information to the first network device. If the terminal device has not received the gap report, the second network device can send the second information to the first network device to indicate the packet loss situation, and trigger the first network device to resend the gap report, so as to avoid the waiting of the terminal device.

[0235] Referring to FIG. 11, as an example, FIG. 11 is a schematic diagram of another communication method 1100 provided by the embodiments of the present application. In the method 1100 shown in FIG. 11, some schemes are the same as or similar to those in the method 900 or the method 1000, and thus the related schemes in the method 900 or the method 1000 can be referred to and combined, and the embodiments of the present application will not be described herein again. The embodiments of the present application mainly explain the differences between the method 1100 and the method 900 or the method 1000. The method 1100 can include the following steps.

[0236] 1130, the terminal device determines first information, the first information indicating first data discarded by the terminal device when connecting with the second network device.

[0237] As an example, after the handover is completed, the terminal device sends the first information to the first network device, the first information indicating the data discarded by the terminal device before the handover. The possible name and specific form of the first information can be referred to the above.

[0238] Optionally, the first information can include the content of the PDCP SN gap report last generated by the terminal device before the handover, or the content of the PDCP SN gap report generated by the terminal device but not yet sent to the second network device, or the content of the PDCP SN gap report not yet correctly received by the second network device.

[0239] 1140, the terminal device sends the first information to the first network device, and accordingly, the first network device receives the first information from the terminal device, the first information being used for making the first network device consider that the first data has been discarded.

[0240] Optionally, after the inter-site handover, before the terminal device sends the first information, if the terminal device has new packet loss, the first data can also include the data discarded by the terminal device after the handover, and the first information is used for indicating the first network device.

[0241] As an example, the first information is used for making the first network device consider that the first data has been discarded, so that after the first network device receives the first information, the first network device can not continue to wait for the first data, or in other words, the first network device can stop detecting or stop receiving the first data, or in other words, the first network device can stop or not start a timer for waiting for the first data.

[0242] Based on the above technical solution, the terminal device can indicate the first data discarded by the terminal device before the inter-station handover to the first network device, so that the first network device can consider that the first data has been discarded, and thus the first network device can not continue to wait for the first data discarded before the handover, avoiding the influence of the packet loss before the handover on the waiting time delay of data after the handover. The first network device can update the receiving window in time, achieving the effect of reducing the waiting time delay of the first network device.

[0243] Optionally, the method 1100 further includes step 1120, the first network device sends third information, and correspondingly, the terminal device receives the third information, the third information indicating that the first network device has not received the first data.

[0244] As an example, the third information can be a PDCP status report of the first network device, indicating the PDCP sequence number of the data (or, the data not received, the data waiting to be received) not received by the first network device, and / or the PDCP sequence number of the data received by the first network device.

[0245] As an example, if the first data is indicated as not received in the third information, and at the same time, the first data is in the data discarded by the terminal device before the handover, the terminal device determines and sends the first information to indicate the first data to the first network device.

[0246] As an example, the data x is discarded by the terminal device before the handover, and the timer used to wait for the data x has timed out before the first network device sends the third information, then the first network device will not continue to wait for the data x, and thus the third information will not indicate the data x as not received. Since the first data needs to be indicated as not received in the third information, the first data indicated by the above first information does not include the data x.

[0247] In the embodiment of the application, the first network device indicates to the terminal device that it has not received the first data, indicating that the first network device is still waiting to receive the first data, that is, the terminal device determines that the first network device is still waiting to receive the first data, and then indicates the first data discarded before the handover to the first network device through the first information, thereby preventing the terminal device from indicating unnecessary data in the first information, and avoiding waste of indication overhead.

[0248] Optionally, the method 1100 further includes step 1110, before the inter-station handover, the second network device sends fourth information, and correspondingly, the first network device receives the fourth information, the fourth information indicating that the second network device has received the second data, the second data being the data discarded by the terminal device when connected with the second network device.

[0249] As an example, for the data x which has not been received by the second network device, or for the data x which is still waiting to be received by the second network device, the second network device can indicate the data x to the first network device through the fourth information, so that the first network device continues to wait for the data x.

[0250] As an example, the second network device obtains the second data discarded by the terminal device before the switching, and after the switching, even if the second network device actually does not receive the second data, the second network device can indicate that the second data has been received to the first network device through the fourth information, or the second network device can not indicate that the second data has not been received to the first network device in the fourth information.

[0251] Further, after the first network device receives the fourth information, for the second data, even if the first network device does not receive the second data, the first network device does not continue to wait for the second data, or in other words, the first network device can stop detecting or stop receiving the second data, or in other words, the first network device can stop or not enable a timer for waiting for the second data, but considers that the second data has been received or delivered.

[0252] In the embodiment of the application, the second network device indicates to the first network device that the second data discarded by the terminal device has been received, so that the first network device does not wait for the second data any more, and the first network device can update the receiving window in time, thereby achieving the effect of reducing the waiting delay of the first network device.

[0253] Further, the third information described in the foregoing also indicates that the first network device has received the second data.

[0254] In combination with the embodiments described in the foregoing, since the third information does not indicate that the first network device has not received the second data, the first information sent by the terminal device indicates the first data, and the intersection of the first data and the second data is empty, that is, the second data will not be indicated in the first information.

[0255] In the embodiment of the application, the first network device indicates to the terminal device that the second data is received data, so that the terminal device considers that the first network device has received the second data, and then the terminal device does not indicate the second data in the first information, thereby preventing the terminal device from indicating unnecessary data in the first information and avoiding waste of indication overhead.

[0256] The above describes the method provided by the embodiments of the application in combination with FIGS. 9 to 11. The following describes the apparatus provided by the embodiments of the application in combination with FIGS. 12 to 14. It should be understood that the description of the apparatus embodiments corresponds to the description of the method embodiments, and therefore, the content not described in detail can be referred to the method embodiments described in the foregoing, and for brevity, will not be described here.

[0257] Referring to FIG. 12, FIG. 12 is a schematic diagram of a communication apparatus 1200 provided by the embodiments of the present application, as an example. The communication apparatus 1200 includes a transceiver unit 1210 and a processing unit 1220. The transceiver unit 1210 can be used to implement corresponding communication functions. The transceiver unit 1210 can also be referred to as a communication interface or a communication unit. The processing unit 1220 can be used for processing, such as determining information bits.

[0258] Optionally, the apparatus 1200 can further include a storage unit, which can be used to store instructions and / or data. The processing unit 1220 can read the instructions and / or data in the storage unit, so that the apparatus implements the foregoing method embodiments.

[0259] The first possible design is that the apparatus 1200 can be a terminal in the foregoing embodiments, and the apparatus 1200 can implement steps or processes corresponding to operations performed by the terminal in the foregoing method embodiments. Specifically, the transceiver unit 1210 can be used to perform operations related to transceiving of the terminal in the foregoing method embodiments (such as operations of transmitting and / or receiving data or messages), and the processing unit 1220 can be used to perform operations related to processing of the terminal in the foregoing method embodiments, or operations other than transceiving (such as operations other than transmitting and / or receiving data or messages).

[0260] In a possible implementation, the transceiver unit 1210 is configured to receive first information from a first network device, the first information indicating first data, the first data being data discarded by a second network device, the second network device being a network device connected by the terminal device before handover; and the processing unit 1220 is configured to consider that the first data has been discarded.

[0261] In another possible implementation, the processing unit 1220 is configured to determine first information, the first information indicating first data, the first data being data discarded when the terminal device is connected to a second network device, the second network device being a network device connected by the terminal device before handover; and the transceiver unit 1210 is configured to send the first information to the first network device, the first information being used to make the first network device consider that the first data has been discarded.

[0262] The second possible design is that the apparatus 1200 can be a network device in the foregoing embodiments, and the apparatus 1200 can implement steps or processes corresponding to operations performed by the network device in the foregoing method embodiments. Specifically, the transceiver unit 1210 can be used to perform operations related to transceiving of the network device in the foregoing method embodiments (such as operations of transmitting and / or receiving data or messages), and the processing unit 1220 can be used to perform operations related to processing of the network device in the foregoing method embodiments, or operations other than transceiving (such as operations other than transmitting and / or receiving data or messages).

[0263] In a possible implementation, the processing unit 1220 is configured to determine first information, the first information indicating first data, the first data being data discarded by a second network device, the second network device being a network device connected by the terminal device before handover; and the transceiver unit 1210 is configured to send the first information to the terminal device, the first information being used to make the terminal device consider that the first data has been discarded.

[0264] In another possible implementation, the transceiver unit 1210 is configured to receive first information from the terminal device, the first information indicating first data, the first data being data discarded by the terminal device when connected to a second network device, the second network device being a network device connected by the terminal device before handover; and the transceiver unit 1210 is further configured to consider that the first data has been discarded.

[0265] It should be understood that the specific process in which each unit performs the corresponding steps described above has been described in detail in the method embodiments described above, and thus will not be described here again for the sake of brevity.

[0266] It should also be understood that the apparatus 1200 herein is embodied in the form of functional units. The term “unit” herein can refer to an application specific integrated circuit (ASIC), an electronic circuit, a processor (for example, a shared processor, a dedicated processor, or a group processor, etc.) and a memory for executing one or more software or firmware programs, a combination of logic circuitry and / or other suitable components that support the described functions. In an optional example, those skilled in the art can understand that the apparatus 1200 can be embodied as the communication apparatus in the above embodiments, and can be used to perform the processes and / or steps corresponding to the communication apparatus in each of the method embodiments described above. To avoid repetition, details will not be described here again.

[0267] The apparatus 1200 of each of the above solutions has the function of implementing the corresponding steps performed by the communication apparatus (for example, the terminal, and for example, the network device) in the above methods. The function can be implemented by hardware, or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions; for example, the transceiver unit can be replaced by a transceiver (for example, the sending unit in the transceiver unit can be replaced by a transmitter, and the receiving unit in the transceiver unit can be replaced by a receiver), and other units, such as the processing unit, can be replaced by a processor, which respectively performs the transceiver operation and the related processing operation in each of the method embodiments.

[0268] In addition, the transceiver unit 1210 described above can also be a transceiver circuit (for example, which can include a receiving circuit and a sending circuit), and the processing unit can be a processing circuit.

[0269] It should be noted that the apparatus in FIG. 12 can be a communication device (e.g., a terminal, or a network device) in the foregoing embodiments, or can be a chip or a chip system, for example, a system on chip (SoC). The transceiver unit can be an input / output circuit or a communication interface, and the processing unit can be a processor or a microprocessor integrated on the chip or an integrated circuit.

[0270] Referring to FIG. 13, as an example, FIG. 13 is a schematic diagram of another communication apparatus 1300 provided by embodiments of the present application. The apparatus 1300 includes a processor 1310, and the processor 1310 is coupled to a memory 1320. The memory 1320 is configured to store computer programs or instructions and / or data, and the processor 1310 is configured to execute the computer programs or instructions stored in the memory 1320, or read the data stored in the memory 1320, to perform the methods in the method embodiments.

[0271] Optionally, the processor 1310 is one or more.

[0272] Optionally, the memory 1320 is one or more.

[0273] Optionally, the memory 1320 is integrated with the processor 1310, or is separately arranged.

[0274] Optionally, as shown in FIG. 13, the apparatus 1300 further includes a transceiver 1330 configured to receive and / or send signals. For example, the processor 1310 is configured to control the transceiver 1330 to receive and / or send signals.

[0275] As an example, the processor 1310 can have the functions of the processing unit 1220 shown in FIG. 12, the memory 1320 can have the function of a storage unit, and the transceiver 1330 can have the functions of the transceiver unit 1210 shown in FIG. 12.

[0276] As an example, the apparatus 1300 is configured to implement the operations performed by a communication device (e.g., a terminal, or a network device) in the method embodiments.

[0277] For example, the processor 1310 is configured to execute the computer programs or instructions stored in the memory 1320, to implement the related operations of the communication device in the method embodiments.

[0278] It should be appreciated that a processor as mentioned in this application can be any known or future developed processor, and more particularly, any custom made or commercially available processor series (or any other processor orders) from any manufacturer.

[0279] It should also be appreciated that a memory as mentioned in this application can be any known or future developed memory, and more particularly, a memory unit of any type including, but not limited to, a volatile memory, a non-volatile memory, or a combination thereof. For example, the non-volatile memory can be a read-only memory (ROM), a programmable ROM (PROM), an erasable PROM (EPROM), an electrically EPROM (EEPROM), a flash memory, or the like. The volatile memory can be a random access memory (RAM), which can be used as external cache memory. By way of example and not limitation, RAM is available from many commercial vendors. For example, the RAM can include a static RAM (SRAM), a dynamic RAM (DRAM), a synchronous DRAM (SDRAM), a double data rate SDRAM (DDR SDRAM), an enhanced SDRAM (ESDRAM), a synchlink DRAM (SLDRAM), and a direct rambus RAM (DR RAM), etc.

[0280] It should be noted that when the processor is a general processor, a DSP, an ASIC, a FPGA, or other programmable logic device, a discrete gate or transistor logic, a discrete hardware component, the memory (storage module) can be integrated in the processor.

[0281] It should also be noted that the memory described herein is intended to include, but not limited to, the memory of these and any other suitable type of memory.

[0282] Referring to FIG. 14, as an example, FIG. 14 is a schematic diagram of a chip system 1400 provided by embodiments of the present application. The chip system 1400 (or also referred to as a processing system) includes a logic circuit 1410 and an input / output interface 1420.

[0283] The logic circuit 1410 can be a processing circuit in the chip system 1400. The logic circuit 1410 can be coupled to a storage unit, invoke instructions in the storage unit, so that the chip system 1400 can implement the methods and functions of embodiments of the present application. The input / output interface 1420 can be an input / output circuit in the chip system 1400, output information processed by the chip system 1400, or input data or signaling information to be processed by the chip system 1400 for processing.

[0284] As an example, the chip system 1400 is configured to implement operations performed by a communication apparatus (e.g., a terminal, or a network device) in the above various method embodiments.

[0285] For example, the logic circuit 1410 is configured to implement processing-related operations performed by a communication apparatus (e.g., a terminal, or a network device) in the above method embodiments; and the input / output interface 1420 is configured to implement sending and / or receiving-related operations performed by a communication apparatus (e.g., a terminal, or a network device) in the above method embodiments.

[0286] Embodiments of the present application also provide a computer-readable storage medium having stored thereon a computer program or instructions for implementing the method performed by a communication apparatus (e.g., a terminal, or a network device) in the above various method embodiments. For example, the computer program or instructions, when executed on a communication apparatus, cause the communication apparatus (e.g., a terminal, or a network device) to perform the above method (e.g., the method 900, the method 1000, or the method 1100).

[0287] Embodiments of the present application also provide a computer program product containing instructions, which, when executed by a computer, implement the method performed by a communication apparatus (e.g., a terminal, or a network device) in the above various method embodiments. For example, the computer program or instructions, when executed on a communication apparatus, cause the communication apparatus (e.g., a terminal, or a network device) to perform the above method (e.g., the method 900, the method 1000, or the method 1100).

[0288] Embodiments of the present application also provide a communication system including the terminal and / or the network device in the above embodiments. For example, the system includes the terminal and the network device in the embodiments of FIG. 9, FIG. 10, or FIG. 11.

[0289] The explanations and beneficial effects of the related contents in any of the above provided devices can refer to the corresponding method embodiments provided above, and will not be repeated here.

[0290] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other manners. For example, the above described device embodiments are merely schematic. For example, the division of the units is only a logical function division. There can be another division manner for the actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections can be indirect couplings or communication connections through some interfaces, devices or units, and can be electrical, mechanical or in other forms.

[0291] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. For example, the computer can be a personal computer, a server, or a network device, etc. The computer instructions can be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions can be transmitted from one website site, computer, server or data center to another website site, computer, server or data center through wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) manner. The computer readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. integrated with one or more available media. The available media can be magnetic media (such as floppy disk, hard disk, magnetic tape), optical media (such as DVD), or semiconductor media (such as solid state disk (SSD), etc. For example, the foregoing available media includes but is not limited to: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk, etc. Various media that can store program codes.

[0292] The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A communication method characterized by comprising: The method is applied to a first network device, the first network device being a network device connected after terminal device switching, and the method comprises: determining first information, the first information indicating first data, the first data being data discarded by a second network device, the second network device being a network device connected before terminal device switching; sending the first information to the terminal device, the first information being used to make the terminal device consider that the first data has been discarded.

2. The method of claim 1, wherein, Before the first information is sent to the terminal device, the method further comprises: determining a first index, the first index being a minimum index corresponding to data forwarded by the second network device to the first network device; determining a second index, the second index being a next index allocated by the first network device for data sent to the terminal device; the index corresponding to the first data being greater than the first index and less than the second index.

3. The method of claim 1, wherein, Before the first information is sent to the terminal device, the method further comprises: receiving second information from the second network device, the second information indicating the first data.

4. The method according to any one of claims 1 to 3, characterized in that, Before the first information is sent to the terminal device, the method further comprises: receiving third information, the third information indicating that the terminal device has not received the first data.

5. A communication method characterized by comprising: The method is applied to a terminal device, and the method comprises: receiving first information from a first network device, the first network device being a network device connected after terminal device switching, the first information indicating first data, the first data being data discarded by a second network device, the second network device being a network device connected before the terminal device switching; considering that the first data has been discarded.

6. The method of claim 5, wherein, Before the first information is received from the first network device, the method further comprises: sending third information, the third information indicating that the terminal device has not received the first data.

7. The method of claim 6, wherein, Before the third information is sent, the method further comprises: receiving fourth information, the fourth information indicating second data, the second data being data discarded by the second network device; and the third information further indicating that the terminal device has received the second data.

8. A communication method characterized by comprising: The method is applied to a terminal device, and the method comprises: determining first information, the first information indicating first data, the first data being data discarded when the terminal device is connected to a second network device, the second network device being a network device connected before the terminal device switching; sending the first information to a first network device, the first network device being a network device connected after terminal device switching, the first information being used to make the first network device consider that the first data has been discarded.

9. The method of claim 8, wherein, Before the first information is sent to the first network device, the method further comprises: receiving third information, the third information indicating that the first network device has not received the first data.

10. A communication method characterized by comprising: The method is applied to a first network device, the first network device being a network device connected after terminal device switching, and the method comprises: receiving first information from a terminal device, the first information indicating first data, the first data being data discarded when the terminal device is connected with a second network device, the second network device being a network device connected before handover of the terminal device; considering that the first data has been discarded.

11. The method of claim 10, wherein, Before the receiving first information from a terminal device, further comprising: sending third information, the third information indicating that the first network device has not received the first data.

12. The method of claim 11, wherein, Before the sending third information, further comprising: receiving fourth information, the fourth information indicating that the second network device has received second data, the second data being data discarded when the terminal device is connected with the second network device; the third information further indicating that the first network device has received the second data.

13. A communications device, characterized by comprising a module or unit for performing the method of any one of claims 1 to 12.

14. A communications device, characterized by comprising a processor configured to cause the communication apparatus to perform the method of any one of claims 1 to 12.

15. A computer-readable storage medium, characterized in that, The computer program product comprises a computer program or instructions, which, when executed on a communication apparatus, cause the communication apparatus to perform the method of any one of claims 1 to 12.

16. A computer program product, characterised in that, The computer program product comprises a computer program or instructions, which, when executed on a communication apparatus, cause the communication apparatus to perform the method of any one of claims 1 to 12.

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