Communication method and communication device

Abstract

Provided are a communication method and a communication device, the method being applicable to a first network device, the first network device being a network device connected after a terminal device is switched, the method comprising: determining first information, the first information indicating first data, the first data being data discarded by a second network device, the second network device is a network device connected before the terminal device is switched; and sending first information to the terminal equipment, wherein the first information is used for enabling the terminal equipment to consider that the first data is discarded. In the application, the switched sender device indicates the data discarded before switching to the receiver device, so that the waiting time delay can be reduced.

Description

Technical Field

[0001] This application relates to the field of communications, and more specifically, to a communication method and a communication device. Background Technology

[0002] Extended reality (XR) refers to various environments that combine reality and virtuality, generated by computing technology and wearable devices, as well as human-machine interaction. XR services typically have high latency requirements, and the packet data convergence protocol (PDCP) layer on the sending side will perform packet loss operations.

[0003] To support terminal mobility, XR services enable inter-site handover, allowing terminal devices to switch connections between different network devices. After an inter-site handover, the receiving device may continue to wait for dropped data packets, causing additional latency. Therefore, reducing latency is a pressing issue that needs to be addressed in this field. Summary of the Invention

[0004] This application provides a communication method and a communication device, which can reduce waiting latency by having the sending device after the handover indicate the data to be discarded before the handover to the receiving device.

[0005] Firstly, a communication method is provided. This method can be applied to the network side; that is, it can be executed by a network device or by a component of the network device (such as a chip, chip system, circuit, or communication module). This application does not limit the scope of the method. The following description mainly uses a network device as an example.

[0006] The method is applied to a first network device, which is the network device that the terminal device connects to after switching. The method may include: determining first information, the first information indicating first data, the first data being data discarded by a second network device, which is the network device that the terminal device connected to before switching; and sending the first information to the terminal device, the first information being used to make the terminal device believe that the first data has been discarded.

[0007] The first information can also be called packet loss information, packet loss report, gap report, sequence number gap report, or Packet Data Convergence Layer Protocol Sequence Number Gap Report (PDCP SN gap report), etc.

[0008] Optionally, if the first network device itself experiences new packet loss before sending the first information, the first data may also include the data discarded by the first network device and be indicated to the terminal device through the first information.

[0009] As an example, the first information is used to make the terminal device think that the first data has been discarded. Thus, after receiving the first information, the terminal device may not continue to wait for the first data, or in other words, the terminal device may stop detecting or stop receiving the first data, or the terminal device may stop or disable the timer used to wait for the first data.

[0010] Based on the above technical solution, the first network device can indicate to the terminal device the first data discarded by the second network device connected to the terminal device before the inter-site handover. This allows the terminal device to recognize that the first data has been discarded, thus eliminating the need for the terminal device to continue waiting for the first data discarded before the handover and preventing packet loss before the handover from affecting the waiting latency of the data after the handover. The terminal device can also update its receiving window in a timely manner, thereby reducing the terminal device's waiting latency.

[0011] In conjunction with the first aspect, in some implementations of the first aspect, before sending the first information to the terminal device, the method may further include: determining a first index, the first index being the smallest index corresponding to data forwarded by the second network device to the first network device; determining a second index, the second index being the 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.

[0012] Specifically, the first network device checks for gaps (PDCPSN gaps) in the forwarded data between the first index and the second index. These gaps can be understood as packet loss in the second network device, or packet loss before the handover. The first data may include all or part of the data corresponding to the gap.

[0013] 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 for the data sent to the terminal device, without the second network device incurring additional signaling overhead to instruct the first network device.

[0014] In conjunction with the first aspect, in some implementations of the first aspect, before sending the first information to the terminal device, the method may further include: receiving second information from the second network device, the second information indicating the first data.

[0015] As an example, the second information can also be called packet loss transmission information or gap transfer information (PDCP SN gaptransfer information), etc.

[0016] As an example, the second network device may send a second message to the first network device during inter-site handover, which indicates the SN information of the first data that was discarded by the second network device.

[0017] Optionally, the second information may include the content of the last PDCP SN gap report generated by the second network device, or the content of the PDCP SN gap report generated after the second network device initiates a 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 the terminal device has not yet correctly received.

[0018] Based on the above technical solution, the second network device directly indicates the first network device to the first network device the first data to be discarded before the handover, so that the first network device can more accurately understand the packet loss situation of the second network device. This solves the problem that the first network device cannot determine the packet loss information itself when the lost data is before the forwarded data. It also avoids the additional waiting delay caused by the terminal device not knowing the packet loss that occurred in the second network device after the handover, which would result in the terminal device continuing to wait for the discarded packets.

[0019] In conjunction with the first aspect, in some implementations of the first aspect, before sending the first information to the terminal device, the method may further include: receiving third information, the third information indicating that the terminal device has not received the first data.

[0020] As an example, the third piece of information could be the PDCP status report of the terminal device, indicating the PDCP sequence number of data that the terminal device has not yet received (or, data that has not been received or is waiting to be received), and / or the PDCP sequence number of data that the terminal device has already received.

[0021] As an example, after the first network device determines a gap in the forwarded data, it can receive a third message indicating that the terminal device has not received the first data. If the first data is indicated as not received in the third message, and the first data is within a gap in the forwarded data, then the first network device determines and sends the first message to the terminal device, indicating the first data.

[0022] Based on the above 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. In other words, the first network device will only indicate the first data discarded by the second network device to the terminal device through the first information after determining that the terminal device is still waiting to receive the first data. This prevents the first network device from indicating unnecessary data in the first information and avoids wasting indication overhead.

[0023] Secondly, a communication method is provided. This method can be applied to the terminal side; that is, it can be executed by the terminal device or by components of the terminal device (such as a chip, chip system, circuit, or communication module). This application does not limit the scope of the method. The following description mainly uses a terminal as an example.

[0024] The method may include: receiving first information from a first network device, the first network device being the network device to which the terminal device connects after switching, the first information indicating first data, the first data being data discarded by a second network device, the second network device being the network device to which the terminal device connects before switching; and assuming that the first data has been discarded.

[0025] In conjunction with the second aspect, in some implementations of the second aspect, before receiving the first information from the first network device, the method may further include: sending third information, the third information indicating that the terminal device has not received the first data.

[0026] In conjunction with the second aspect, in some implementations of the second aspect, before sending the third information, the method may further include: receiving fourth information, the fourth information indicating second data, the second data being data discarded by the second network device; the third information further indicating that the terminal device has received the second data.

[0027] As an example, if the terminal device receives the second data before the handover and it is discarded by the second network device, then after the handover, even if the terminal device does not actually receive the second data, the terminal device can indicate to the first network device that it has received the second data through the third information. Alternatively, the terminal device may not indicate to the first network device that it has not received the second data in the third information.

[0028] 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. The intersection of the first data and the second data is empty, that is, the first information will not indicate the second data.

[0029] Based on the above technical solution, the terminal device knows that the second network device has discarded the second data, so it will 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 believes that the terminal device has received the second data. As a result, the first network device will not indicate the second data in the first information, thus preventing the first network device from indicating unnecessary data in the first information and avoiding wasting indication overhead.

[0030] For the beneficial effects and possible designs of the second aspect, please refer to the relevant description in the first aspect, which will not be repeated here.

[0031] Thirdly, a communication method is provided. This method can be applied to the terminal side; that is, it can be executed by the terminal device or by components of the terminal device (such as a chip, chip system, circuit, or communication module). This application does not limit the scope of the method. The following description mainly uses a terminal as an example.

[0032] The method may include: determining first information, the first information indicating first data, the first data being data discarded when the terminal device connects to a second network device, the second network device being the network device the terminal device was connected to before the switch; sending the first information to a first network device, the first network device being the network device the terminal device connected to after the switch, the first information being used to make the first network device believe that the first data has been discarded.

[0033] Optionally, the first information may include the content of the last PDCP SN gap report generated by the terminal device before the handover, or the content of a PDCP SN gap report generated by the terminal device but not yet sent to the second network device, or the content of a PDCP SN gap report that the second network device has not yet correctly received.

[0034] Optionally, if a new packet loss occurs at the terminal device after the inter-site handover but before the terminal device sends the first information, the first data may also include the data discarded after the handover and be indicated to the first network device through the first information.

[0035] As an example, the first information is used to make the first network device believe that the first data has been discarded, so that after receiving the first information, the first network device may not continue to wait for the first data, or in other words, the first network device may stop detecting or stop receiving the first data, or the first network device may stop or disable the timer used to wait for the first data.

[0036] Based on the above technical solution, the terminal device can indicate to the first network device the first data that was discarded before the inter-site handover, so that the first network device can assume that the first data has been discarded. Therefore, the first network device does not need to continue waiting for the first data discarded before the handover, avoiding the impact of packet loss before the handover on the waiting latency of the data after the handover. The first network device can also update its receiving window in a timely manner, thereby reducing the waiting latency of the first network device.

[0037] In conjunction with the third aspect, in some implementations of the third aspect, before sending the first information to the first network device, the method may further include: receiving third information, the third information indicating that the first network device has not received the first data.

[0038] As an example, the third information could be the PDCP status report of the first network device, indicating the PDCP sequence number of data that the first network device has not yet received (or, data that has not been received or is waiting to be received), and / or the PDCP sequence number of data that the first network device has already received.

[0039] As an example, if the first data is indicated as not received in the third information, and the first data is among the data discarded before the terminal device switches over, then the terminal device determines and sends the first information to indicate the first data to the first network device.

[0040] Based on the above 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. In other words, the terminal device will only indicate to the first network device the first data that it discarded before the handover through the first information after it determines that the first network device is still waiting to receive the first data. This prevents the terminal device from indicating unnecessary data in the first information and avoids wasting indication overhead.

[0041] Fourthly, a communication method is provided. This method can be applied to the network side; that is, it can be executed by a network device or by a component of the network device (such as a chip, chip system, circuit, or communication module). This application does not limit this. The following description mainly uses a network device as an example.

[0042] The method is applied to a first network device, which is the network device that the terminal device connects to after switching. The method may include: receiving first information from the terminal device, the first information indicating first data, the first data being data discarded when the terminal device connects to a second network device, the second network device being the network device that the terminal device connected to before switching; and assuming that the first data has been discarded.

[0043] In conjunction with the fourth aspect, in some implementations of the fourth aspect, before receiving the first information from the terminal device, the method may further include: sending third information, the third information indicating that the first network device has not received the first data.

[0044] In conjunction with the fourth aspect, in some implementations of the fourth aspect, before sending the third information, the method may further include: receiving the fourth information, the fourth information indicating that the second network device has received the second data, the second data being data discarded when the terminal device connects to the second network device; the third information also indicating that the first network device has received the second data.

[0045] As an example, if the second network device receives the second data before the handover and it is discarded by the terminal device, then after the handover, even if the second network device does not actually receive the second data, the second network device can indicate to the first network device that it has received the second data through the fourth information. Alternatively, the second network device may not indicate to the first network device that it has not received the second data in the fourth information.

[0046] Furthermore, after the first network device receives the fourth information, even if the first network device has not received the second data, the first network device will not continue to wait for the second data. In other words, the first network device can stop detecting or stop receiving the second data, or the first network device can stop or disable the timer used to wait for the second data, and instead consider the second data to have been received or delivered.

[0047] Based on the above technical solution, the second network device indicates to the first network device that it has received the second data discarded by the terminal device, so that the first network device will no longer wait for the second data. The first network device can update the receiving window in a timely manner, thereby reducing the waiting latency of the first network device.

[0048] Furthermore, by indicating to the terminal device that the second data has been received, the first network device makes the terminal device believe that the first network device has received the second data, and thus the terminal device will not indicate the second data in the first information, thereby preventing the terminal device from indicating unnecessary data in the first information and avoiding wasting indication overhead.

[0049] For the beneficial effects and possible designs of the fourth aspect, please refer to the relevant description in the third aspect, which will not be repeated here.

[0050] Fifthly, a communication device is provided. The device may include: 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 to which the terminal device was connected before switching; and a transceiver unit configured to send the first information to the terminal device, the first information being used to make the terminal device believe that the first data has been discarded.

[0051] In conjunction with the fifth aspect, in some implementations of the fifth aspect, the processing unit is further configured to determine a first index, which is the smallest index corresponding to the data forwarded by the second network device to the first network device; the processing unit is further configured to determine a second index, which is the next index allocated by the first network device for the data sent to the terminal device; the index corresponding to the first data is greater than the first index and less than the second index.

[0052] In conjunction with the fifth aspect, in some implementations of the fifth aspect, the transceiver unit is further configured to receive second information from the second network device, the second information indicating the first data.

[0053] In conjunction with the fifth aspect, in some implementations of the fifth aspect, the transceiver unit is also configured to receive third information, which indicates that the terminal device has not received the first data.

[0054] In a sixth aspect, a communication device is provided. The device may include: a transceiver unit for receiving 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 the network device to which the terminal device was connected before switching; and a processing unit for determining that the first data has been discarded.

[0055] In conjunction with the sixth aspect, in some implementations of the sixth aspect, the transceiver unit is also used to send third information, the third information indicating that the terminal device has not received the first data.

[0056] In conjunction with the sixth aspect, in some implementations of the sixth aspect, the transceiver unit is further configured to receive fourth information, the fourth information indicating second data, the second data being data discarded by the second network device; the third information further indicates that the terminal device has received the second data.

[0057] In a seventh aspect, a communication device is provided. The device may include: 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 to a second network device, the second network device being the network device the terminal device was connected to before the handover; and a transceiver unit configured to send the first information to a first network device, the first information being used to cause the first network device to believe that the first data has been discarded.

[0058] In conjunction with the seventh aspect, in some implementations of the seventh aspect, the transceiver unit is further configured to receive third information, the third information indicating that the first network device has not received the first data.

[0059] Eighthly, a communication device is provided. The device may include: a transceiver unit 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 to a second network device, the second network device being the network device the terminal device was connected to before the handover; the transceiver unit is further configured to consider that the first data has been discarded.

[0060] In conjunction with the eighth aspect, in some implementations of the eighth aspect, the transceiver unit is also used to send third information, the third information indicating that the first network device has not received the first data.

[0061] In conjunction with the eighth aspect, in some implementations of the eighth aspect, the transceiver unit 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 to the second network device; the third information also indicates that the first network device has received the second data.

[0062] A ninth aspect provides a communication apparatus for performing the methods of any one of the first to fourth aspects and any possible implementation thereof. Specifically, the apparatus may include units and / or modules for performing the methods of any one of the first to fourth aspects and any possible implementation thereof, such as processing units and / or communication units.

[0063] In one implementation, the device is a communication device (such as a terminal device or a network device). When the device is a communication device, the communication unit can be a transceiver or an input / output interface; 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.

[0064] In another implementation, the device is a chip, chip system, circuit, or communication module for communication equipment (such as terminal equipment or network equipment). When the device is a chip, chip system, or circuit for communication equipment, the communication unit may be an input / output interface, interface circuit, output circuit, input circuit, pin, or related circuit on the chip, chip system, or circuit; the processing unit may be at least one processor, processing circuit, or logic circuit.

[0065] A tenth aspect provides a communication device comprising: at least one processor configured to cause the device to perform the methods of any one of the first to fourth aspects and any possible implementation thereof.

[0066] Optionally, the at least one processor is configured to execute computer programs or instructions to perform the methods of any one of the first to fourth aspects and any possible implementation thereof.

[0067] Optionally, the device further includes a memory for storing the computer program or instructions.

[0068] Optionally, the at least one processor is coupled to a memory for storing the computer program or instructions. The memory may be located externally to the device.

[0069] Optionally, the device also includes a communication interface through which the processor reads instructions from memory. This can be understood as the communication interface being coupled to the processor and used to input computer programs or instructions to the processor, or to output information from the processor.

[0070] Unless otherwise specified, or if the transmission and acquisition / reception operations involved do not contradict their actual function or internal logic in the relevant description, they can be understood as output, input, or other operations, or as transmission and reception operations performed by radio frequency circuits and antennas. This application does not limit them in this regard.

[0071] In one implementation, the device is a communication device (such as a terminal device or a network device).

[0072] In another implementation, the device is a chip, chip system, circuit, or communication module for communication equipment (such as terminal equipment or network equipment). Optionally, the chip is a modem chip, also known as a baseband chip, or a system-on-chip (SoC) chip containing a modem core, or a system-in-package (SIP) chip.

[0073] Eleventhly, a computer-readable storage medium is provided, on which a computer program (e.g., program code) or instructions are stored, which, when executed on a communication device, cause the communication device to perform the methods of any one of the first to fourth aspects and any possible implementation thereof.

[0074] In a twelfth aspect, a computer program product containing instructions is provided, which, when run on a computer, causes the computer to perform the methods of any one of the first to fourth aspects and any possible implementation thereof.

[0075] In a thirteenth aspect, a communication system is provided, including a first communication device and a second communication device. The first communication device is used to execute the method provided in any implementation of the first aspect, and the second communication device is used to execute the method provided in any implementation of the second aspect. Attached Figure Description

[0076] Figure 1 This is a schematic diagram of a communication architecture applicable to embodiments of this application.

[0077] Figure 2 This is a schematic diagram of a base station CU-DU separation architecture applicable to embodiments of this application.

[0078] Figure 3 This is a schematic diagram of a 5G XR communication architecture applicable to embodiments of this application.

[0079] Figure 4 This is a schematic diagram of a video coding model applicable to embodiments of this application.

[0080] Figure 5 This is a schematic diagram of PDCP packet loss applicable to embodiments of this application.

[0081] Figure 6 This is a schematic diagram of PDCP reordering applicable to embodiments of this application.

[0082] Figure 7 This is a schematic diagram illustrating an increase in downlink waiting latency after a handover, applicable to an embodiment of this application.

[0083] Figure 8 This is a schematic diagram illustrating an increase in uplink waiting latency after a switchover, applicable to an embodiment of this application.

[0084] Figure 9 This is a schematic diagram of a communication method 900 provided in an embodiment of this application.

[0085] Figure 10 This is a schematic diagram of another communication method 1000 provided in an embodiment of this application.

[0086] Figure 11 This is a schematic diagram of another communication method 1100 provided in the embodiments of this application.

[0087] Figure 12 This is a schematic diagram of a communication device 1200 provided in an embodiment of this application.

[0088] Figure 13 This is a schematic diagram of another communication device 1300 provided in an embodiment of this application.

[0089] Figure 14 This is a schematic diagram of a chip system 1400 provided in an embodiment of this application. Detailed Implementation

[0090] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0091] Before introducing the scheme of this application, the following points should be noted.

[0092] (1) In this application, "instruction" can include direct instruction, indirect instruction, explicit instruction, implicit instruction, etc. When describing an instruction information as indicating A, it can be understood that the instruction information carries A, carries the identifier of A, carries B which is associated with A, carries the identifier of B which is associated with A, etc. In other words, if the receiving side of an instruction information can determine A based on the instruction information, it can be described as the instruction information indicating A, and the specific method of determination is not limited. When it is understood that the instruction information carries A, "instruction" can be replaced with "includes". In this case, a statement such as "send / receive instruction information, the instruction information indicates A" can be replaced with "send / receive A".

[0093] In this application, the information indicated by the instruction information is called the information to be instructed. In specific implementations, there are many ways to indicate the information to be instructed, such as, but not limited to, directly indicating the information to be instructed, such as the information to be instructed itself or its index. It can also indirectly indicate the information to be instructed by indicating other information, where there is a relationship between the other information and the information to be instructed. It can also indicate only a part of the information to be instructed, while the other parts are known or pre-agreed upon. For example, the instruction of specific information can be achieved by using a pre-agreed (e.g., protocol-defined) arrangement of various pieces of information, thereby reducing instruction overhead to some extent. Furthermore, the information to be instructed can be sent as a whole or divided into multiple sub-information pieces, and the sending period and / or timing of these sub-information pieces can be the same or different.

[0094] (2) In this application, the expression " / " is used to indicate that the objects before and after are in an "or" relationship; for example, A / B can mean: A or B. The expression "and / or" is used to indicate that the objects before and after are in a relationship of either "and" or "or"; for example, A and / or B can mean the following: A exists alone, B exists alone, A and B exist simultaneously, where A and B can be single or multiple. "At least one of the following" or similar expressions are used to indicate any combination of the listed items; for example, at least one of A, B and / or C can mean the following: A exists alone, B exists alone, C exists alone, A and B exist simultaneously, B and C exist simultaneously, A and C exist simultaneously, A, B and C exist simultaneously, where A, B, and C can be single or multiple.

[0095] (3) In this application, "send" and "receive" indicate the direction of signal transmission. For example, "send information to XX" can be understood as the destination of the information being XX, which may include direct transmission via the air interface or indirect transmission by other units or modules via the air interface. "Receive information from YY" can be understood as the source of the information being YY, which may include direct reception from YY via the air interface or indirect reception from YY by other units or modules via the air interface. "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 occur 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 the device via a bus, wiring, or interface.

[0096] (4) In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terms and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0097] (5) In this application, "first" and "second" are used for descriptive convenience only to distinguish objects and are not intended to limit the scope of the embodiments of this application. They are not used to describe the order or sequence of features. It should be understood that the objects described in this way can be interchanged where appropriate so as to describe solutions other than those in the embodiments of this application.

[0098] (6) In this application, "predefined" can mean a standard protocol predefined, or it can mean a pre-agreed or pre-negotiated agreement between devices. Here, "protocol" can refer to a standard protocol in the field of communications, for example, it may include fourth-generation (4G) protocols. th Generation 4G network, fifth generation (5G) network th This application does not limit the scope to network protocols such as generation (5G), new radio (NR) protocols, 5.5G network protocols, future communication network protocols, and related protocols applied in future communication systems.

[0099] (7) In this application, the words “exemplary,” “for example,” etc., are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as an “example” in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word “example” is intended to present the concept in a concrete manner. In the embodiments of this application, “of,” “corresponding, relevant,” and “corresponding” may sometimes be used interchangeably, and it should be noted that their intended meanings are consistent unless their distinction is emphasized.

[0100] First, let me introduce the communication system to which this application applies.

[0101] The technical solutions provided in this application can be applied to various communication systems, such as 5th generation (5G) or new radio (NR) systems, long term evolution (LTE) systems, LTE frequency division duplex (FDD) systems, and LTE time division duplex (TDD) systems. The technical solutions provided in this application can also be applied to future communication systems, such as future mobile communication networks. 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 systems. 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.

[0102] As an example, a satellite communication system includes a satellite base station and terminal equipment. The satellite base station provides communication services to the terminal equipment. Satellite base stations can also communicate with each other. A satellite can act as a base station or as a terminal device. Here, "satellite" can refer to drones, hot air balloons, low-Earth orbit satellites, medium-Earth orbit satellites, high-Earth orbit satellites, etc. "Satellite" can also refer to non-terrestrial base stations or non-terrestrial equipment.

[0103] As an example, V2X communication can include: vehicle-to-vehicle (V2V) communication, vehicle-to-infrastructure (V2I) communication, vehicle-to-pedestrian (V2P) communication, and vehicle-to-network (V2N) communication.

[0104] In a communication system, a device can send signals to or receive signals from another device. These signals can include information, signaling, or data. The device can also be replaced by an entity, network entity, communication equipment, communication module, node, communication node, etc. This application uses a device as an example for description.

[0105] The terminal device in this application embodiment can be a device or module that accesses the aforementioned communication system and has corresponding communication functions. The terminal device can include various devices with wireless communication capabilities, which can be used to connect people, objects, machines, etc. The terminal device can be widely used in various scenarios, such as: cellular communication, D2D, V2X, peer-to-peer (P2P), M2M, MTC, IoT, virtual reality (VR), augmented reality (AR), extended reality (XR), industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, smart cities, drones, robots, 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. Terminal equipment can be user equipment (UE), terminal, fixed equipment, mobile station equipment or mobile equipment, subscriber unit, handheld device, vehicle-mounted equipment, wearable device, cellular phone, smartphone, session initiation protocol (SIP) phone, wireless data card, personal digital assistant (PDA), computer, tablet computer, laptop computer, wireless modem, handset, laptop computer, computer with wireless transceiver capability, smart book, vehicle, satellite, global positioning system (GPS) device, target tracking device, aircraft (e.g., drone, helicopter, multiple helicopters, four helicopters, or airplanes), ship, remote control device, smart home device, industrial equipment, transportation vehicle with wireless communication capability, communication module, or roadside unit with terminal function, all conforming to the 3rd generation partnership project (3GPP) standard. The device may be a wireless communication unit (RSU), or a device built into the aforementioned device (e.g., a communication module, modem, or chip in the aforementioned device), or other processing devices connected to the wireless modem.

[0106] By way of example and not limitation, in this embodiment, the terminal device can also be a wearable device. Wearable devices, also known as wearable smart devices, are a general term for devices that utilize wearable technology to intelligently design and develop everyday wearables, such as glasses, gloves, watches, clothing, and shoes. Wearable devices are portable devices that are worn directly on the body or integrated into the user's clothing or accessories. Wearable devices are not merely hardware devices, but also achieve powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include those that are feature-rich, large in size, and can achieve complete or partial functions without relying on a smartphone, such as smartwatches or smart glasses, as well as those that focus on a specific type of application function and require the use of other devices such as smartphones, such as various smart bracelets and smart jewelry for vital sign monitoring.

[0107] It should be understood that in certain scenarios, a UE can also be used as a base station. For example, a UE can act as a scheduling entity, providing sidelink signaling between UEs in scenarios such as V2X, D2D, or P2P.

[0108] In this embodiment, the device for implementing the functions of a terminal device, i.e., the terminal device, can be the terminal device itself, or it can be any device capable of supporting the terminal device in implementing the functions, such as a chip system, chip, circuit, or communication module (i.e., a communication module that performs communication functions). This device can be installed in the terminal device. In this embodiment, the chip system can be composed of chips, or it can include chips and other discrete devices. Furthermore, the device can also be configured with program instructions for performing corresponding communication functions.

[0109] The network device in this application embodiment can be a device or module with corresponding communication functions. The network device can be a device used to communicate with terminal devices; it can also be called an access network device or a wireless access network device, such as a base station. In this application embodiment, the network device can refer to a radio access network (RAN) node (or device) that connects the terminal device to the wireless network. A base station can broadly encompass, or be replaced by, various names including: NodeB, evolved NodeB (eNB), next-generation NodeB (gNB), relay station, access point, transmitting and receiving point (TRP), transmitter, master station, auxiliary station, motor slide retainer (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. A base station can be a macro base station, micro base station, relay node, donor node, or a combination thereof. A base station can also refer to a communication module, modem, or chip installed within the aforementioned equipment or apparatus. A base station can also be a mobile switching center, a device that performs base station functions in D2D, V2X, and M2M communications, a network-side device in future communication networks, or a device that performs base station functions in future communication systems. A base station can support networks using the same or different access technologies. The embodiments of this application do not limit the specific technologies or device forms used in the network equipment.

[0110] Base stations can be fixed or mobile. For example, a helicopter or drone can be configured to act as a mobile base station, and one or more cells can move depending on the location of the mobile base station. In other examples, a helicopter or drone can be configured as a device to communicate with another base station.

[0111] In some deployments, the network devices mentioned in the embodiments of this application may be devices including CU, or DU, or devices including CU and DU, or devices with control plane CU nodes (central unit-control plane (CU-CP)) and user plane CU nodes (central unit-user plane (CU-UP)) and DU nodes.

[0112] In some deployments, multiple RAN nodes collaborate to assist terminal devices in achieving wireless access, with different RAN nodes each implementing some of the base station's functions. For example, RAN nodes can be CUs, DUs, CU-CPs, CU-UPs, or radio units (RUs). CUs and DUs can be configured separately or included in the same network element, such as a BBU. RUs can be included in radio equipment or radio units, such as RRUs, AAUs, or RRHs.

[0113] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, a radio access network can also be an open radio access network (O-RAN) architecture. In an O-RAN system, CU can also be called an open CU (open CU, O-CU), DU can also be called an open DU (open DU, O-DU), CU-CP can also be called an open CU-CP (O-CU-CP), CU-UP can also be called an open CU-UP (O-CU-UP), and RU can also be called an open RU (open RU, O-RU). Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software modules and hardware modules.

[0114] In this embodiment, the device for implementing the functions of a network device can be a network device itself, or a device capable of supporting the network device in implementing those functions, such as a chip system, chip, circuit, or communication module (i.e., a communication module that performs communication functions). This device can be installed within the network device. In this embodiment, the chip system can be composed of chips, or it can include chips and other discrete devices. Furthermore, the device can be configured with program instructions for performing corresponding communication functions. This embodiment only uses a network device as an example to illustrate the device for implementing the functions of a network device, and does not limit the solution of this embodiment.

[0115] Network devices and terminal devices can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on water; and they can also be deployed in the air on airplanes, balloons, and satellites. This application does not limit the scenario in which the network devices and terminal devices are located.

[0116] See Figure 1 , Figure 1 This is a schematic diagram of a communication architecture applicable to embodiments of this application. In this application, a 5G base station is used as an example to illustrate the embodiments. Figure 1 As shown, in a 5G system, a base station is called a gNB / ng-eNB, which mainly includes 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). All of these can be represented by gNB, and gNBs connect to each other via the Xn interface. The gNB connects to the 5G core network via the NG interface. In some deployments, a gNB can consist of a CU and a DU, which involves splitting the functions of the base station in the original access network. Some base station functions are deployed in a CU, and the remaining functions are deployed in a DU. Multiple DUs share a single CU, which saves costs and facilitates network expansion. The splitting of CU and DU can be based on the protocol stack. One possible approach is to deploy RRC, SDAP, and PDCP layers in the CU, and the remaining RLC, MAC, and PHY layers in the DU. CU and DU connect via the F1 interface. CU represents a gNB connected to the core network via the NG interface. CU also represents a gNB connected to other gNBs via the Xn interface. CU can also represent a gNB connected to other eNBs via the X2 port to perform dual-connection operations.

[0117] See Figure 2 , Figure 2 This is a schematic diagram of a base station CU-DU separation architecture applicable to embodiments of this application. For example... Figure 2As shown, the CU can be further divided into the control plane (CU-CP) and the user plane (CU-UP). CU-CP is responsible for control plane functions, mainly including RRC and the corresponding PDCP (PDCP-C). PDCP-C is primarily responsible for control plane data encryption / decryption, integrity protection, and data transmission. CU-UP is responsible for user plane functions, mainly including SDAP and the corresponding PDCP (PDCP-U). SDAP is primarily responsible for processing core network data and mapping flows to bearers. PDCP-U is primarily responsible for data plane encryption / decryption, integrity protection, header compression, sequence number maintenance, and data transmission. CU-CP and CU-UP are connected via the E1 interface. CU-CP and CU-UP are connected to the core network via the NG interface. The control plane (F1-C) and DU are connected via the F1 interface. CU-UP is connected to the user plane (F1-U) and DU via the F1 interface. Alternatively, PDCP-C may also be located within CU-UP.

[0118] See Figure 3 , Figure 3 This is a schematic diagram of a 5G XR communication architecture applicable to embodiments of this application. Exemplarily, in... Figure 3 In this context, for a single service, taking the following behavior as an example, data is generated by the application server, forwarded through the Data Network (DN), sent to the core network via the N6 interface, and then transmitted to the base station via the N3 interface. The base station then sends the data to the UE via the Uu air interface. Furthermore, sidelink (SL) communication occurs between user communication devices (e.g., XR devices).

[0119] Understandable, Figure 3This is merely an example and not a limitation on the application scenario of this application. The core network equipment refers to equipment in the core network (CN) that provides service support to the terminal. Examples of core network equipment include: access and mobility management function (AMF) entities, session management function (SMF) entities, user plane function (UPF) entities, etc., which are not listed here. The AMF entity is responsible for terminal access management and mobility management; the SMF entity is responsible for session management, such as user session establishment; the UPF entity can be a user plane functional entity, mainly responsible for connecting to external networks. It should be noted that in this application, entities can also be called network elements or functional entities. For example, an AMF entity can also be called an AMF network element or an AMF functional entity, and an SMF entity can also be called an SMF network element or an SMF functional entity, etc.

[0120] To facilitate understanding of the embodiments of this application, the terms used in this application will be briefly explained.

[0121] 1. XR services:

[0122] XR refers to a combined real and virtual environment generated by computing technology and wearable devices, as well as human-machine interaction. It includes several typical forms: VR, AR, and mixed reality (MR). XR is one of the key 5G multimedia applications currently being considered in the industrial sector. 3GPP Rel-17 has modeled and analyzed the service characteristics of XR. Typically, XR services generate data frames periodically at a certain frame rate. Taking an AR service with a frame rate of 60fps as an example, 60 frames of video images are generated per second, with approximately one video frame appearing every 16.66ms. A single video frame may be transmitted by multiple data packets, which may be divided into one or more protocol data unit sets (PDU sets).

[0123] XR services typically have high latency requirements. Taking uplink AR services as an example, the typical packet delay budget (PDB) is 30ms, meaning the maximum transmission delay between the arrival of a data packet at the UE access layer and its arrival at the N6 interface of the UPF is 30ms. If a data packet is not successfully transmitted within the PDB time, it is considered to have timed out and become useless. Alternatively, XR services may also consider a packet set delay budget (PSDB), which has a similar meaning to PDB, defining the maximum transmission delay for a set of data packets (a PDU set). For uplink, this refers to the maximum 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; the opposite applies to downlink. The network should strive to complete data scheduling and transmission within the delay budget to avoid data timeouts that could impact service experience.

[0124] 2. PDU set importance (PSI):

[0125] In XR services, data of varying importance may appear within the same data stream. This is due to the application's encoding method. Taking XR video services as an example, applications can use inter-frame predictive coding to compress the amount of data to be transmitted. Simply put, this type of encoding takes advantage of the fact that most content in adjacent video frames remains unchanged, transmitting only the data of the changed parts of the frame, while using previous data for the unchanged parts. For example, in live streaming, the background usually doesn't change, so only the complete data needs to be transmitted in the first frame. Subsequent video frames only transmit data showing changes in the foreground figures, and the background data doesn't need to be transmitted again. The receiving player can directly use the background data from the first frame to generate the images for subsequent video frames.

[0126] One classic coding method is group-of-picture (GOP) coding. In this method, a GOP contains several consecutive video frames. The first frame, called an intra-coded picture (I) frame, uses intra-coding and contains complete image information, allowing for independent encoding and decoding. The remaining frames, called predictive-coded picture (P) frames, use predictive coding and contain only partial image information, requiring the preceding frames for encoding and decoding. Another similar coding method divides a video frame into multiple video slices. Some slices use intra-coding, while others use predictive coding, referred to as I-slices and P-slices, respectively. Encoding and decoding of a subsequent P-slice depends on the corresponding I-slice in the preceding frame.

[0127] See Figure 4 , Figure 4 This is a schematic diagram of a video encoding model applicable to embodiments of this application. The dependency relationship between the two types of video frame encoding and decoding is as follows: Figure 4 As shown.

[0128] It should be noted that a single frame or slice transmitted over a wireless network may correspond to one or more PDUsets. 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, I-frame / I-slice data has higher importance during data transmission. In the event of network congestion, reliable transmission of I-frames / I-slices should be prioritized to ensure a smooth service experience.

[0129] To differentiate the unequal importance of different data within the same data stream, 3GPP introduced the concept of PDU set importance (PSI). According to 3GPP specification 23.700, a QoS stream for an XR service can contain PDU sets of varying importance, identified by their PSI. For example, in an XR video stream, the PSI of the PDU set corresponding to an I-frame / I-slice might be stronger than that of the PDU set corresponding to a P-frame / P-slice. This is because the encoding and decoding of P-frames / P-slices depend on I-frames / I-slices; therefore, I-frame / I-slice data has higher importance. For downlink data transmission, the PSI of each PDU set is provided to the RAN by the CN (Network Controller). For uplink data transmission, the PSI of each PDU set is identified by the terminal device itself.

[0130] 3. PDCP packet loss (PDCP discard):

[0131] See Figure 5 , Figure 5 This is a schematic diagram of PDCP packet loss applicable to embodiments of this application. In a wireless network, the PDCP layer on the transmitting side performs packet loss operations. Specifically, when the PDCP layer receives a PDCP service data unit (SDU) from the upper layer, it starts a discard timer for it. When the discard timer expires, the PDCP layer discards the PDCP SDU and its corresponding PDCP PDU. The PDCP PDU is the processed data of the PDCP SDU, and the processing includes encryption, compression, and adding a protocol header. If the PDCP PDU has already been delivered to a lower layer (such as the RLC layer), the lower layer will be notified of packet loss.

[0132] For the PDU set concept introduced in XR services, the aforementioned PDCP packet loss mechanism can be enhanced by enabling PDU set discard. Specifically, when the PDCP layer receives a PDCP SDU from the upper layer, it still starts a discard timer. However, when the discard timer for a particular PDCP SDU expires, the PDCP layer will discard all PDCP SDUs in the PDU set to which that PDCP SDU belongs, along with their corresponding PDCP PDUs. Similarly, if any PDCP PDUs have already been delivered to the lower layer, the lower layer will be notified.

[0133] In XR services, a priority-based packet drop function has also been introduced. Specifically, when network congestion occurs, the network can preemptively drop some low-priority (i.e., high PSI) data packets. For example, for uplink, the network can instruct the UE to drop packets based on importance. After receiving the instruction, when the PDCP layer receives a PDCP SDU from the upper layer, if it finds that the PDCP SDU belongs to a low-priority PDU set, it starts a drop timer shorter than the normal duration (e.g., in extreme cases, the duration of this short timer is 0). This means that low-priority data stays in the buffer for a shorter time, has fewer transmission opportunities, and is more likely to be dropped, thereby alleviating network congestion. The network can also perform similar operations on downlink data.

[0134] Furthermore, importance-based packet dropping can also be combined with PDU set discard, that is, when the network or UE discards a low-importance data packet, all data packets in the PDU set to which that data packet belongs are also discarded.

[0135] 4. Inter-station handover:

[0136] To support terminal mobility, terminals can switch connections between different base stations. During inter-station handover, the network needs to maintain lossless data transmission. To achieve this, after handover, the network and terminal use PDCP status reports to determine if there are any data packets that need to be retransmitted. For downlink transmission, after handover, the terminal sends a PDCP status report to the target base station. The status report indicates the PDCP sequence numbers of data packets that the terminal has not yet received (and is waiting to receive). The target base station should then transmit these data packets to the terminal. Similarly, for uplink transmission, after handover, the target base station sends a PDCP status report to the terminal. The status report indicates the PDCP sequence numbers of data packets that the target base station is still waiting to receive, and the terminal then transmits these data packets to the target base station.

[0137] See Figure 6 , Figure 6 This is a schematic diagram of PDCP reordering applicable to embodiments of this application.

[0138] One possible implementation is that when the sending-side PDCP entity discards a data packet, the receiving-side PDCP entity may experience a reception gap because it did not receive that data packet. For example... Figure 6 As shown, the receiving-side PDCP entity receives data packets 1 and 2 and normally submits them to the upper layer. After that, the receiving-side PDCP receives data packets 4 and 5. Since data packet 3 was not received, a gap is created. At this time, the receiving-side PDCP will not immediately submit data packet 4 to the upper layer. Instead, it will start a reordering timer. During the operation of this timer, if the receiving-side PDCP receives data packet 3, it can submit data packets 3, 4, and 5 to the upper layer. Otherwise, it will not submit data packets 4 and 5 to the upper layer until the timer expires.

[0139] If packet 3 has already been discarded by the sending-side PDCP entity, the receiving-side PDCP may not have a chance to receive packet 3. However, the receiving-side PDCP will still wait until the reordering timer expires, which in turn causes the already received packets 4 and 5 to be delivered with a delay. Especially after XR services support packet loss based on PDU sets and packet loss based on PSI, the sending-side PDCP entity will experience more frequent and larger packet loss, which will lead to more gaps on the receiving side and increase the waiting latency for data that has not been discarded.

[0140] As an example, after packet loss, the sending-side PDCP entity can notify the receiving-side PDCP of the packet loss information through a sequence number gap report or a Packet Data Convergence Layer Protocol sequence number gap report (PDCP SN gap report). For example, the PDCP SN (sequence number) of the dropped packet can be provided to the receiving-side PDCP, so that the receiving-side PDCP entity does not need to continue waiting for the dropped packet. For instance, in the example above, the sending-side PDCP can inform the receiving-side PDCP that packet 3 has been dropped. Upon receiving this information, the receiving-side PDCP can immediately stop the reordering timer and forward packets 4 and 5, no longer waiting to receive packet 3. This method avoids the latency problem caused by gaps in the receiving-side due to packet loss on the sending side.

[0141] The trigger condition for a PDCP SN gap report is PDCP packet loss. In inter-site handover scenarios, packet loss may occur at the source station, while the target station is unaware of packet loss occurring at the source station. This can cause the receiving side to continue waiting for dropped data packets after the handover, resulting in additional waiting latency.

[0142] See Figure 7 , Figure 7 This diagram illustrates an increase in downlink waiting latency after handover, applicable to embodiments of this application. For downlink transmission, if packet loss occurs before handover, the source station may generate a PDCP SN gap report to notify the terminal of the packet loss, for example, the source station may notify the terminal that data packet x has been dropped. However, since the transmission of the PDCP SN gap report takes time, the terminal may not receive the gap report before handover. Afterwards, the terminal switches to the target station, and because it did not receive the gap report from the source station, it is unaware that data packet x has been dropped, and continues to wait for data packet x. However, since data packet x was actually dropped at the source station, the terminal can only wait until the reordering timer expires, resulting in increased data latency after data packet x.

[0143] See Figure 8 , Figure 8 This is a schematic diagram illustrating an increase in uplink waiting latency after handover, applicable to embodiments of this application. For uplink transmission, if packet loss occurs before handover, the terminal may generate a PDCP SN gap report to notify the source station of the packet loss situation. For example, the terminal may notify the target station that data packet x has been dropped. Regardless of whether the source station receives the gap report, after handover is completed, the target station is unaware that data packet x has been dropped and may continue to wait for data packet x, resulting in increased data waiting latency afterwards.

[0144] In view of this, this application proposes a communication method and communication device, which can reduce waiting latency by having the sending device after the handover indicate the data to be discarded before the handover to the receiving device.

[0145] The methods provided by the embodiments of this application will be described in detail below with reference to the accompanying drawings. The embodiments provided by this application can be applied to the scenarios shown in the above figures, and are not limited thereto.

[0146] See Figure 9 As an example, Figure 9 This is a schematic diagram of a communication method 900 provided in an embodiment of this application. For ease of description, a terminal device and a network device are used as examples for illustrative purposes. The terminal device can be replaced by its components (e.g., a chip, chip system, circuit, or communication module), and the network device can be replaced by its components (e.g., a chip, chip system, circuit, or communication module). Furthermore, the steps described below as being performed by a single execution entity can also be divided into steps performed by multiple execution entities, which can be logically and / or physically separated. Figure 9 The method 900 shown may include the following steps.

[0147] Method 900 includes steps 940 and 950, and optionally, method 900 includes steps 910, 920 and 930.

[0148] 910, the second network device sends forwarding data, and correspondingly, the first network device receives the forwarding data.

[0149] As an example, in this embodiment of the application, the first network device may also be referred to as the target station or target base station (target gNB), and the first network device may be the network device that the terminal device connects to after inter-station handover.

[0150] As an example, in this embodiment of the application, the second network device may also be called a source station or source base station (sourcegNB), and the second network device may be a network device that the terminal device connects to before inter-site handover.

[0151] As an example, forwarded data can include user plane data, such as audio data and video streams, as well as control plane data, such as handover requests and resource allocations. During inter-site handover, forwarded data is used to ensure a smooth handover and the continuity of user services.

[0152] It should be understood that in the embodiments of this application, the data can correspond to the SN, and the data can be replaced with PDCP PDU, PDCP SDU, data packet or PDU set, etc. The embodiments of this application do not limit this.

[0153] Optionally, the forwarded data is a PDCP SDU and corresponds to the SN.

[0154] For example, the second network device sends forwarded data to the first network device. The SN corresponding to this forwarded data is 5, 6, and 7, which correspond to three specific data.

[0155] 920, the second network device sends a status transfer (SN) message, and the first network device receives the status transfer message accordingly.

[0156] The status transmission information can be used to mark the status of the data corresponding to the SN. The status transmission information can also be called serial number status transmission information or serial number status indication information, etc., and its naming does not limit the scope of protection of the embodiments of this application.

[0157] As an example, the status information can be an SN status message passed by the second network device to the first network device during the handover process. The status information can indicate the next PDCP SN to the first network device, that is, the SN that the first network device should assign to the next new PDCP SDU, or the SN that the first network device should assign to the next data that has not yet been associated with a SN.

[0158] Optionally, the new PDCP SDU may come from a second network device, or the new PDCP SDU may come from the core network.

[0159] It should be understood that step 920 can be performed before, after, or simultaneously with step 910. This application embodiment does not limit the execution order of steps 910 and 920.

[0160] 940, the first network device determines the first information, which indicates the first data, which is the data discarded by the second network device. The first information can also be called packet loss information, packet loss report, hole report, or PDCP SNgap report, etc.

[0161] Specifically, the determination of the first information can be achieved through the following steps:

[0162] Step 1: Determine the first index, which is the smallest index corresponding to the data forwarded by the second network device to the first network device.

[0163] The data forwarded by the second network device to the first network device may include the forwarding data in step 910 above.

[0164] As an example, if the SN corresponding to the forwarded data in step 910 is 5, 6, or 7, then the minimum index corresponding to the data forwarded by the second network device to the first network device can be 5, that is, the value of the first index is 5.

[0165] Step 2: Determine the second index, which is the next index assigned by the first network device for the data sent to the terminal device.

[0166] The next index assigned by the first network device to the data sent to the terminal device can be indicated by the status transmission information in step 920 above.

[0167] As an example, if the status transmission information in step 920 indicates that the next sequence number is 9, then the next index assigned by the first network device to the data sent to the terminal device can be 9, that is, the value of the second index is 9.

[0168] It should be understood that step 2 can be performed before, after, or simultaneously with step 1. This application embodiment does not limit the execution order of steps 1 and 2.

[0169] Step 3: Determine the index corresponding to the first data, which is greater than the first index and less than the second index.

[0170] The first data may be data discarded by the second network device, or in other words, the first data may be data discarded before the inter-site handover.

[0171] Specifically, the first network device checks for gaps (PDCPSN gaps) in the forwarded data between the first index and the second index. These gaps can be understood as packet loss in the second network device, or packet loss before the handover. The first data may include all or part of the data corresponding to the gap.

[0172] As an example, if the SN corresponding to the forwarded data in step 910 is 5, 6, or 7, and the status transmission information in step 920 indicates that the next sequence number is 10, then the value of the first index is 5, the value of the second index is 10, and the gaps in the forwarded data between the first index and the second index are 8 and 9, then the aforementioned first data may include all or part of the data corresponding to SNs 8 and 9.

[0173] As another example, if the SN corresponding to the forwarded data in step 910 is 3, 4, or 7, and the status transmission information in step 920 indicates that the next sequence number is 9, then the value of the first index is 3, the value of the second index is 9, and the gaps in the forwarded data between the first index and the second index are 5, 6, and 8, then the aforementioned first data may include all or part of the data corresponding to SNs 5, 6, and 8.

[0174] In this embodiment of the application, 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 for the data sent to the terminal device, without the second network device incurring additional signaling overhead to instruct the first network device.

[0175] The above indexes, such as the minimum index, can be replaced with other parameters, such as the maximum index and the number of SNs.

[0176] 950, the first network device sends first information to the terminal device, and correspondingly, the terminal device receives the first information from the first network device, which is used to make the terminal device believe that the first data has been discarded.

[0177] Optionally, the first information may specifically indicate the first data in one or more of the following forms 1 to 3:

[0178] Form 1: The first information indicates the first data via SN.

[0179] As an example, if the SN corresponding to the first data is 4, 5, 8 and 9, then the first information can directly indicate SN 4, SN 5, SN 8 and SN 9.

[0180] Form 2: The first information is indicated by the SN corresponding to the first data in the first data and a bitmap.

[0181] The bitmap corresponds to several SNs after the first data in the first data. Each bit in the bitmap corresponds to one SN. If a bit in the bitmap is the first value (0 or 1), it means that the data packet corresponding to the SN of that bit has been discarded.

[0182] As an example, if the first data corresponds to SNs 4, 5, 8, and 9, then the first information can indicate SN4 and also contain a bitmap (10011), where the "1" corresponds to SN 5, SN 8, and SN 9 respectively.

[0183] Form 3: The first information indicates the first data by using the SN corresponding to several data points in the first data and the corresponding length L.

[0184] Where L indicates that the data packets corresponding to the L SNs following this SN are also dropped, and the L SNs following this SN may or may not include this SN.

[0185] As an example, suppose that the L SNs following the SN contain the SN, and the SNs corresponding to the first data are 4, 5, 8 and 9. Then the first information can indicate SN 4 and L1 = 2 and SN 8 and L2 = 2, indicating that the first data includes two data starting from SN 4 (SN4, SN5) and two data starting from SN 8 (SN 8, SN9).

[0186] Optionally, if the first network device itself experiences new packet loss before sending the first information, the first data may also include the data discarded by the first network device and be indicated to the terminal device through the first information.

[0187] As an example, the first information is used to make the terminal device think that the first data has been discarded. Thus, after receiving the first information, the terminal device may not continue to wait for the first data, or in other words, the terminal device may stop detecting or stop receiving the first data, or the terminal device may stop or disable the timer used to wait for the first data.

[0188] In this embodiment, the first network device can indicate to the terminal device the first data discarded by the second network device connected to the terminal device before the inter-site handover. This allows the terminal device to recognize that the first data has been discarded, thus eliminating the need for the terminal device to continue waiting for the first data discarded before the handover and preventing packet loss before the handover from affecting the waiting latency of the data after the handover. The terminal device can also update its receiving window in a timely manner, thereby reducing the waiting latency of the terminal device.

[0189] Optionally, the method 900 further includes step 930, in which the terminal device sends third information, and correspondingly, the first network device receives the third information, which indicates that the terminal device has not received the first data.

[0190] As an example, the third piece of information could be the PDCP status report of the terminal device, indicating the PDCP sequence number of data that the terminal device has not yet received (or, data that has not been received or is waiting to be received), and / or the PDCP sequence number of data that the terminal device has already received.

[0191] As an example, after the first network device determines a gap in the forwarded data, it can receive a third message indicating that the terminal device has not received the first data. If the first data is indicated as not received in the third message, and the first data is within a gap in the forwarded data, then the first network device determines and sends the first message to the terminal device, indicating the first data.

[0192] As an example, if data x is located in a gap in the forwarded data, and the timer used by the terminal device to wait for data x expires before sending the third information, the terminal device will not continue to wait for data x, and therefore the third information will not indicate that data x has not been received. Since the first data needs to be indicated as not received in the third information, the first data indicated by the aforementioned first information does not include data x.

[0193] In this embodiment of the application, 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. In other words, the first network device will only indicate the first data discarded by the second network device to the terminal device through the first information 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 wasting indication overhead.

[0194] Optionally, before the inter-site handover, the second network device sends a fourth message, and the terminal device receives the fourth message, which indicates the second data, which is the data discarded by the second network device.

[0195] Furthermore, the aforementioned third information also indicates that the terminal device has received the second data.

[0196] As an example, if the terminal device receives the second data before the handover and it is discarded by the second network device, then after the handover, even if the terminal device does not actually receive the second data, the terminal device can indicate to the first network device that it has received the second data through the third information. Alternatively, the terminal device may not indicate to the first network device that it has not received the second data in the third information.

[0197] In conjunction with the embodiments described above, 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 first information will not indicate the second data.

[0198] In this embodiment, the terminal device knows that the second network device has discarded the second data, so it will 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 believes that the terminal device has received the second data. As a result, the first network device will not indicate the second data in the first information, thus preventing the first network device from indicating unnecessary data in the first information and avoiding wasting indication overhead.

[0199] See Figure 10 As an example, Figure 10 This is a schematic diagram of another communication method 1000 provided in an embodiment of this application. Figure 10In method 1000, some solutions are the same as or similar to those in method 900. Therefore, relevant solutions in method 900 can be referred to and combined. These solutions will not be repeated in this application. This application mainly illustrates the differences between method 1000 and method 900. Method 1000 may include the following steps.

[0200] 1010, the second network device sends second information, and correspondingly, the first network device receives the second information from the second network device, which indicates the first data.

[0201] As an example, the second information can also be called packet loss transmission information or gap transfer (PDCP SN gaptransfer) information, etc. Its specific form can be referred to the first information described above, and will not be repeated here in the embodiments of this application.

[0202] As an example, the second network device may send a second message to the first network device during inter-site handover, which indicates the SN information of the first data that was discarded by the second network device.

[0203] Optionally, the second information may include the content of the last PDCP SN gap report generated by the second network device, or the content of the PDCP SN gap report generated after the second network device initiates a 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 the terminal device has not yet correctly received.

[0204] As an example, the terminal device's ability to determine the existence of gaps in forwarded data may not be accurate in some scenarios. For instance, if the data discarded by the second network device is located before all forwarded data, the first network device may not be able to determine the existence of a gap based on the minimum index corresponding to the forwarded data.

[0205] For example, if the second network device discards the data corresponding to SN 3 and SN 4, and 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 transmission information sent by the second network device indicates that the next sequence number is 8, the first network device may not be able to determine that the second network device has discarded the data corresponding to SN 3 and SN 4.

[0206] In this embodiment, the second network device directly indicates the first network device to the first network device the first data to be discarded before the handover, so that the first network device can more accurately understand the packet loss situation of the second network device. This solves the problem that the first network device cannot determine the packet loss information itself when the lost data is before the forwarded data. It also avoids the additional waiting delay caused by the terminal device not knowing the packet loss that occurred in the second network device after the handover, which would result in the terminal device continuing to wait for the discarded packets.

[0207] 1030, the first network device determines first information, which indicates first data, which is data discarded by the second network device.

[0208] As an example, the first data may include all or part of the packet loss data of the second network device indicated by the second information.

[0209] Optionally, the first data indicated by the first information is the same as the packet loss data indicated by the second information.

[0210] 1040, the first network device sends first information to the terminal device, and correspondingly, the terminal device receives the first information from the first network device, which is used to make the terminal device believe that the first data has been discarded.

[0211] Optionally, if the first network device itself experiences new packet loss before sending the first information, the first data may also include the data discarded by the first network device and be indicated to the terminal device through the first information.

[0212] As an example, the first information is used to make the terminal device think that the first data has been discarded. Thus, after receiving the first information, the terminal device may not continue to wait for the first data, or in other words, the terminal device may stop detecting or stop receiving the first data, or the terminal device may stop or disable the timer used to wait for the first data.

[0213] Optionally, the above method 1000 further includes step 1020, in which the terminal device sends third information, and correspondingly, the first network device receives the third information, which indicates that the terminal device has not received the first data.

[0214] As an example, after receiving the second information, the first network device can receive a 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 within the packet loss data indicated by the second information, then the first network device determines and sends the first information to indicate the first data to the terminal device.

[0215] As an example, the second network device discards data x and indicates this to the first network device via second information. Before the terminal device sends the third information, the timer used to wait for data x has expired. Therefore, the terminal device will not continue waiting for data x, and the third information will not indicate that data x was not received. Since the first data needs to be indicated as not received in the third information, the first data indicated by the aforementioned first information does not include data x.

[0216] In this embodiment of the application, 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. In other words, the first network device will only indicate the first data discarded by the second network device to the terminal device through the first information 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 wasting indication overhead.

[0217] Optionally, before the inter-site handover, the second network device sends a fourth message, and the terminal device receives the fourth message, which indicates the second data, which is the data discarded by the second network device.

[0218] Furthermore, the aforementioned third information also indicates that the terminal device has received the second data.

[0219] As one possible implementation, in a CU-DU separation architecture, the DU can notify the CU whether the PDCPSN gap report was successfully sent.

[0220] As an example, for downlink, after a PDCP entity located at the CU loses a packet, an SN gap report is generated. The SN gap report itself is a PDCP control PDU, which is passed to the DU and then queued with other ordinary data packets for air interface transmission.

[0221] Optionally, in RLC AM mode, when the RLC layer determines that a data packet has been correctly transmitted to the terminal device, the RLC layer can indicate to the PDCP layer that the corresponding data has been correctly transmitted.

[0222] Specifically, in a CU-DU separation scenario, the DU can indicate to the CU the highest PDCP SN that was correctly transmitted and the range of PDCP SNs that were correctly transmitted, so that the PDCP layer knows which SNs correspond to which data packets have been successfully transmitted to the terminal device.

[0223] Optionally, in RLC UM mode, the RLC layer cannot reliably determine whether a data packet has been transmitted correctly, but it can still provide feedback to the PDCP on whether the data packet has been sent.

[0224] Specifically, in a 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 SNs correspond to which data packets have been sent.

[0225] Specifically, for the PDCP SN gap report, since it is a PDCP control PDU and is not associated with any PDCP SN, the CU may not be able to know whether the gap report has been transmitted correctly or has been transmitted through the above information.

[0226] In one possible implementation, when the CU submits the SN gap report to the DU, it carries the control PDU SN to identify the gap report.

[0227] Optionally, the aforementioned control PDU SN is carried in the PDCP header or GTP-U header.

[0228] As an example, after the DU correctly transmits the gap report, it sends feedback to the CU with "correctly transmitted control PDU SN" and / or "correctly transmitted control PDU SN range".

[0229] As another example, after the DU sends a gap report, it sends feedback to the CU on "sent control PDU SN" and / or "sent control PDU SN range".

[0230] In this embodiment of the application, under the CU-DU separation architecture, the DU can notify the CU whether a gap report has been sent or correctly transmitted, thereby enabling the CU to determine whether the terminal device is aware of the packet loss situation.

[0231] 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 has been 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.

[0232] In this embodiment, the second network device determines whether the terminal device received a gap report before the handover. If the terminal device has received it, no additional waiting delay will occur, and the second network device may not send the second information to the first network device. If the terminal device has not received the gap report, the second network device may send the second information to the first network device to indicate packet loss and trigger the first network device to retransmit the gap report, thus avoiding waiting for the terminal device.

[0233] See Figure 11 As an example, Figure 11 This is a schematic diagram of another communication method 1100 provided in the embodiments of this application. Figure 11 In the method 1100 shown, some solutions are the same as or similar to those in method 900 or method 1000. Therefore, the relevant solutions in method 900 or method 1000 can be referred to and combined. The embodiments of this application will not be repeated. The embodiments of this application mainly illustrate the differences between method 1100 and method 900 and method 1000. Method 1100 may include the following steps.

[0234] 1130, the terminal device determines first information, which indicates first data, which is data discarded when the terminal device connects with the second network device.

[0235] As an example, after the handover is completed, the terminal device sends a first message to the first network device to indicate the data that the terminal device discarded before the handover. Please refer to the above for possible names and specific forms of the first message.

[0236] Optionally, the first information may include the content of the last PDCP SN gap report generated by the terminal device before the handover, or the content of a PDCP SN gap report generated by the terminal device but not yet sent to the second network device, or the content of a PDCP SN gap report that the second network device has not yet correctly received.

[0237] 1140, the terminal device sends first information to the first network device, and correspondingly, the first network device receives the first information from the terminal device. The first information is used to make the first network device believe that the first data has been discarded.

[0238] Optionally, if a new packet loss occurs at the terminal device after the inter-site handover but before the terminal device sends the first information, the first data may also include the data discarded after the handover and be indicated to the first network device through the first information.

[0239] As an example, the first information is used to make the first network device believe that the first data has been discarded, so that after receiving the first information, the first network device may not continue to wait for the first data, or in other words, the first network device may stop detecting or stop receiving the first data, or the first network device may stop or disable the timer used to wait for the first data.

[0240] Based on the above technical solution, the terminal device can indicate to the first network device the first data that was discarded before the inter-site handover, so that the first network device can assume that the first data has been discarded. Therefore, the first network device does not need to continue waiting for the first data discarded before the handover, avoiding the impact of packet loss before the handover on the waiting latency of the data after the handover. The first network device can also update its receiving window in a timely manner, thereby reducing the waiting latency of the first network device.

[0241] Optionally, the above method 1100 further includes step 1120, in which the first network device sends third information, and the terminal device receives the third information accordingly, the third information indicating that the first network device has not received the first data.

[0242] As an example, the third information could be the PDCP status report of the first network device, indicating the PDCP sequence number of data that the first network device has not yet received (or, data that has not been received or is waiting to be received), and / or the PDCP sequence number of data that the first network device has already received.

[0243] As an example, if the first data is indicated as not received in the third information, and the first data is among the data discarded before the terminal device switches over, then the terminal device determines and sends the first information to indicate the first data to the first network device.

[0244] As an example, if data x is discarded by the terminal device before the handover, and the timer used by the first network device to wait for data x expires before sending the third information, then the first network device will not continue to wait for data x, and consequently, the third information will not indicate that data x was not received. Since the first data needs to be indicated as not received in the third information, the first data indicated by the aforementioned first information does not include data x.

[0245] In this 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. In other words, the terminal device will only indicate to the first network device the first data that it discarded before the handover through the first information after determining that the first network device is still waiting to receive the first data. This prevents the terminal device from indicating unnecessary data in the first information and avoids wasting indication overhead.

[0246] Optionally, the above method 1100 further includes step 1110, in which the second network device sends fourth information before the inter-site handover, and the first network device receives the fourth information accordingly. The fourth information indicates that the second network device has received the second data, which is the data discarded when the terminal device connects with the second network device.

[0247] As an example, for data x that the second network device has not yet received, or for data x that the second network device is still waiting to receive, the second network device can indicate data x to the first network device through the fourth information, so that the first network device can continue to wait for the data x.

[0248] As an example, if the second network device receives the second data before the handover and it is discarded by the terminal device, then after the handover, even if the second network device does not actually receive the second data, the second network device can indicate to the first network device that it has received the second data through the fourth information. Alternatively, the second network device may not indicate to the first network device that it has not received the second data in the fourth information.

[0249] Furthermore, after the first network device receives the fourth information, even if the first network device has not received the second data, the first network device will not continue to wait for the second data. In other words, the first network device can stop detecting or stop receiving the second data, or the first network device can stop or disable the timer used to wait for the second data, and instead consider the second data to have been received or delivered.

[0250] In this embodiment, the second network device indicates to the first network device that it has received the second data discarded by the terminal device, so that the first network device will no longer wait for the second data. The first network device can update the receiving window in a timely manner, thereby reducing the waiting latency of the first network device.

[0251] Furthermore, the aforementioned third information also indicates that the first network device has received the second data.

[0252] In conjunction with the embodiments described above, 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 first information will not indicate the second data.

[0253] In this embodiment of the application, the first network device indicates to the terminal device that the second data has been received, so that the terminal device believes that the first network device has received the second data. As a result, the terminal device will not indicate the second data in the first information, thereby preventing the terminal device from indicating unnecessary data in the first information and avoiding wasting indication overhead.

[0254] The above, combined with Figures 9 to 11 The methods provided in the embodiments of this application are described in detail below. Figures 12 to 14 The apparatus provided in the embodiments of this application is described in detail. It should be understood that the description of the apparatus embodiments corresponds to the description of the method embodiments. Therefore, for content not described in detail, please refer to the method embodiments above. For the sake of brevity, it will not be repeated here.

[0255] See Figure 12 As an example, Figure 12 This is a schematic diagram of a communication device 1200 provided in an embodiment of this application. The communication device 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 to perform processing, such as determining information bits.

[0256] Optionally, the device 1200 may further include a storage unit, which can be used to store instructions and / or data, and the processing unit 1220 can read the instructions and / or data in the storage unit to enable the device to implement the aforementioned method embodiments.

[0257] In a first possible design, the device 1200 can be the terminal described in the foregoing embodiments. The device 1200 can implement the steps or processes executed by the terminal corresponding to those described in the above method embodiments. Specifically, the transceiver unit 1210 can be used to perform transceiver-related operations (such as sending and / or receiving data or messages) of the terminal in the above method embodiments, and the processing unit 1220 can be used to perform processing-related operations of the terminal in the above method embodiments, or operations other than transceiver operations (such as operations other than sending and / or receiving data or messages).

[0258] In one possible implementation, the transceiver unit 1210 is used 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 the network device to which the terminal device was connected before the handover; and the processing unit 1220 is used to consider that the first data has been discarded.

[0259] Another possible implementation is a processing unit 1220, which is used to determine first information, the first information indicating first data, the first data being data discarded when the terminal device connects to the second network device, the second network device being the network device the terminal device was connected to before the switch; and a transceiver unit 1210, which is used to send first information to the first network device, the first information being used to make the first network device believe that the first data has been discarded.

[0260] In a second possible design, the device 1200 can be a network device as described in the foregoing embodiments. This device 1200 can implement the steps or processes performed by the network device corresponding to those described in the method embodiments above. Specifically, the transceiver unit 1210 can be used to perform transceiver-related operations (such as sending and / or receiving data or messages) of the network device described in the method embodiments above, and the processing unit 1220 can be used to perform processing-related operations of the network device described in the method embodiments above, or operations other than transceiver operations (such as operations other than sending and / or receiving data or messages).

[0261] One possible implementation is that the processing unit 1220 is used to determine first information, the first information indicating first data, the first data being data discarded by the second network device, the second network device being the network device that the terminal device was connected to before the handover; the transceiver unit 1210 is used to send the first information to the terminal device, the first information being used to make the terminal device believe that the first data has been discarded.

[0262] Another possible implementation is that the transceiver unit 1210 is used to receive first information from the terminal device, the first information indicating first data, the first data being data discarded when the terminal device connects to the second network device, and the second network device being the network device that the terminal device was connected to before the switch; the transceiver unit 1210 is also used to consider that the first data has been discarded.

[0263] It should be understood that the specific process of each unit performing the above-mentioned corresponding steps has been described in detail in the above method embodiments, and will not be repeated here for the sake of brevity.

[0264] It should also be understood that the device 1200 here is embodied in the form of a functional unit. The term "unit" here can refer to an application-specific integrated circuit (ASIC), electronic circuitry, a processor (e.g., a shared processor, a proprietary processor, or a group processor, etc.) and memory for executing one or more software or firmware programs, integrated logic circuitry, and / or other suitable components supporting the described functions. In an alternative example, those skilled in the art will understand that the device 1200 can be specifically the communication device in the above embodiments, and can be used to execute the various processes and / or steps corresponding to the communication device in the above method embodiments; to avoid repetition, these will not be described again here.

[0265] The apparatus 1200 of each of the above-described schemes has the function of implementing the corresponding steps performed by the communication device (such as a terminal or a network device) in the above-described methods. The function can be implemented in 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 (e.g., the transmitting 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 processing units, can be replaced by processors, each performing the transceiver operations and related processing operations in the respective method embodiments.

[0266] In addition, the transceiver unit 1210 may also be a transceiver circuit (for example, it may include a receiving circuit and a transmitting circuit), and the processing unit may be a processing circuit.

[0267] It should be pointed out that, Figure 12The device mentioned can be the communication equipment (such as a terminal or network device) in the foregoing embodiments, or it can be a chip or a chip system, such as a system on a chip (SoC). The transceiver unit can be an input / output circuit or a communication interface; the processing unit is a processor, microprocessor, or integrated circuit integrated on the chip. No limitations are imposed here.

[0268] See Figure 13 As an example, Figure 13 This is a schematic diagram of another communication device 1300 provided in an embodiment of this application. The device 1300 includes a processor 1310, which is coupled to a memory 1320. The memory 1320 is used to store computer programs or instructions and / or data. The processor 1310 is used to execute the computer programs or instructions stored in the memory 1320, or to read the data stored in the memory 1320, in order to execute the methods in the above method embodiments.

[0269] Optionally, there may be one or more processors 1310.

[0270] Optionally, the memory 1320 may be one or more.

[0271] Alternatively, the memory 1320 can be integrated with the processor 1310, or it can be set separately.

[0272] Optionally, such as Figure 13 As shown, the device 1300 also includes a transceiver 1330 for receiving and / or transmitting signals. For example, a processor 1310 is used to control the transceiver 1330 to receive and / or transmit signals.

[0273] As an example, processor 1310 may have Figure 12 The processing unit 1220 shown has the function of a storage unit, the memory 1320 can have the function of a storage unit, and the transceiver 1330 can have... Figure 12 The function of the transceiver unit 1210 shown is illustrated.

[0274] As one option, the device 1300 is used to implement the operations performed by a communication device (such as a terminal or a network device) in the various method embodiments described above.

[0275] For example, processor 1310 is used to execute computer programs or instructions stored in memory 1320 to implement the relevant operations of the communication device in the various method embodiments described above.

[0276] It should be understood that the processor mentioned in the embodiments of this application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0277] It should also be understood that the memory mentioned in the embodiments of this application can be volatile memory and / or non-volatile memory. Non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory can be random access memory (RAM). For example, RAM can be used as an external cache. By way of example and not limitation, RAM includes the following forms: static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0278] It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA, or other programmable logic device, discrete gate or transistor logic device, or discrete hardware component, the memory (storage module) can be integrated into the processor.

[0279] It should also be noted that the memory described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0280] See Figure 14 As an example, Figure 14 This is a schematic diagram of a chip system 1400 provided in an embodiment of this application. The chip system 1400 (or may also be referred to as a processing system) includes logic circuitry 1410 and an input / output interface 1420.

[0281] The logic circuit 1410 can be a processing circuit in the chip system 1400. The logic circuit 1410 can be coupled to a memory unit, calling instructions from the memory unit, enabling the chip system 1400 to implement the methods and functions of the embodiments of this application. The input / output interface 1420 can be an input / output circuit in the chip system 1400, outputting processed information from the chip system 1400, or inputting data or signaling information to be processed into the chip system 1400 for processing.

[0282] As one approach, the chip system 1400 is used to implement operations performed by a communication device (such as a terminal or a network device) in the various method embodiments described above.

[0283] For example, logic circuit 1410 is used to implement processing-related operations performed by a communication device (such as a terminal, or a network device) in the above method embodiments; input / output interface 1420 is used to implement sending and / or receiving-related operations performed by a communication device (such as a terminal, or a network device) in the above method embodiments.

[0284] This application also provides a computer-readable storage medium storing a computer program or instructions for implementing the methods executed by a communication device (such as a terminal or a network device) in the above-described method embodiments. For example, when the computer program or instructions are run on the communication device, the communication device (such as a terminal or a network device) executes the above-described methods (such as method 900, method 1000, or method 1100).

[0285] This application also provides a computer program product comprising instructions that, when executed by a computer, implement the methods performed by a communication device (such as a terminal or a network device) in the above-described method embodiments. For example, when the computer program or instructions are run on the communication device, the communication device (such as a terminal or a network device) performs the above-described methods (such as method 900, method 1000, or method 1100).

[0286] This application also provides a communication system, which includes the terminals and / or network devices described in the above embodiments. For example, the system includes... Figure 9 , Figure 10 or Figure 11The terminal and network device in the embodiment.

[0287] The explanations and beneficial effects of the relevant contents in any of the devices provided above can be found in the corresponding method embodiments provided above, and will not be repeated here.

[0288] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection of apparatus or units may be electrical, mechanical, or other forms.

[0289] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially 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 this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. 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. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state disks, SSDs). For example, the aforementioned available media include, but are not limited to, USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks, and other media capable of storing program code.

[0290] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the 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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