Communication method and device

Abstract

The present application provides a communication method and device, the method includes a step of: a first central unit of a network device receiving first information from a terminal device, the first information indicating a type of the terminal device, the first central unit sending second information to a first distributed unit of the network device, the second information indicating a type of the terminal device.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to Chinese Patent Application No. 202110240470.5, entitled “TERMINAL CAPABILITY INDICATION METHOD, TERMINAL, AND NETWORK DEVICE”, filed with the State Intellectual Property Office of the People's Republic of China on March 4, 2021, which is incorporated herein by reference in its entirety. This application claims priority to Chinese Patent Application No. 202110352120.8, entitled “COMMUNICATION METHOD AND DEVICE”, filed with the State Intellectual Property Office of the People's Republic of China on March 31, 2021, which is incorporated herein by reference in its entirety.

[0002] TECHNICAL FIELD Embodiments of the present application relate to the field of wireless communication technologies, and in particular to communication methods and devices. [Background technology]

[0003] Currently, in LTE Rel-15 and 5G NR evolution, a new network architecture is provided, as shown in Figure 1. In this network architecture, the base station functions are divided into two units: a central unit (CU) and a distributed unit (DU). The CU handles radio upper layer protocol stack functions, such as the radio resource control (RRC) layer and the packet data convergence protocol (PDCP) layer. The DU handles the physical layer of baseband processing and some layer 2 protocol stack functions, such as the radio link control (RLC) layer, the media access control (MAC) layer, and the physical layer (PHY). The interface between the CU and the DU is the F1 interface.

[0004] Currently, in the CU-DU network architecture, network devices cannot implement better scheduling and access management for reduced capability (REDCAP) terminal devices. Summary of the Invention

[0005] SUMMARY OF THE PRESENT APPLICATION The embodiments of the present application provide a communication method and device, so that a network device can perform better scheduling and access management for reduced capability terminal devices. [Means for solving the problem]

[0006] According to a first aspect, the present application provides a communication method, the method including: a first central unit of a network device receiving first information from a terminal device, the first information indicating a type of the terminal device; the first central unit transmitting second information to a first distributed unit of the network device; 2 The information indicates the type of terminal device.

[0007] For example, the central unit of the network device may be a CU, and the distributed unit of the network device may be a DU. According to the aforementioned method, after the terminal device accesses the network device, the first central unit of the network device can send second information to the first distributed unit of the network device based on the first information received from the terminal device, so that the first distributed unit of the network device can obtain the type of the terminal device in time. For example, the type of the terminal device may be a reduced capability terminal device (e.g., a REDCAP terminal device, or an NB-IoT terminal device). Or, the type of the terminal device may be , lowIt may be a type of terminal device with reduced capabilities. For example, if the terminal device with reduced capabilities is a REDCAP terminal device, the type of terminal device with reduced capabilities may be, as another example, a further subdivision terminal device with different capabilities within the REDCAP terminal device, or a further subdivision terminal device with different antennas within the REDCAP terminal device.

[0008] Therefore, in the access process of the terminal device or when the terminal device is handed over to the first distributed unit of the network device, the first distributed unit of the network device can schedule corresponding resources and access priorities of the terminal device in time based on the type of the terminal device in the second information obtained from the first central unit of the network device, to implement scheduling management of the terminal device with reduced capability.

[0009] In possible implementations, the type of terminal device includes any one of the following: a reduced capability terminal device or a type of reduced capability terminal device.

[0010] In a possible embodiment, the first central unit receives the first information via the first distributed unit.

[0011] According to the above-mentioned method, when a terminal device accesses a network through a first distributed unit and a first central unit, the terminal device can transmit first information to the first central unit in a transparent transmission manner through the first distributed unit.

[0012] In a possible embodiment, the first central unit receives the first information via the second distributed unit, the second distributed unit being a distributed unit accessed by the terminal device before the terminal device is handed over to the first distributed unit.

[0013] According to the above method, when accessing the second distributed unit, the terminal device can send first information to the first central unit via the second distributed unit, so that the first central unit can obtain the type of the terminal device in time. When the terminal device is handed over to the first distributed unit, the first distributed unit can obtain the second information based on the second information sent by the first central unit to ensure that the first distributed unit can still schedule resources of the terminal device in time after the handover.

[0014] In a possible embodiment, the first central unit receives first information transmitted by the second central unit, the second central unit being a central unit accessed by the terminal device before the terminal device is handed over to the first central unit.

[0015] In a possible embodiment, the first distribution unit schedules resources of the terminal devices and / or access priorities of the terminal devices based on the second information.

[0016] In a possible embodiment, the first central unit transmits the second information to a third distributed unit, which is the distributed unit to which the terminal device is handed over from the first distributed unit.

[0017] According to the above method, the first central unit can send the second information to the third distributed unit when the terminal device is handed over to the third distributed unit, so that the third distributed unit can obtain the type of the terminal device earlier during handover, and can provide resource scheduling corresponding to a terminal device with reduced capabilities earlier for the terminal device in the process of the terminal device accessing the third distributed unit.

[0018] In a possible embodiment, the first central unit transmits first information to a third central unit, which is a central unit to which the terminal device is handed over from the first central unit, and the first information is to be used by the third central unit to transmit second information to a third distributed unit, which is a distributed unit to which the terminal device is handed over from the first distributed unit.

[0019] According to the above-mentioned method, the first central unit can send the first information to the third central unit when the terminal device is handed over to the third central unit, so that the third central unit can obtain the type of the terminal device earlier during handover, and can send the second information to the third distributed unit after the terminal device accesses the third central unit, so that the third distributed unit can provide resource scheduling corresponding to the terminal device of reduced capability earlier for the terminal device.

[0020] In a possible implementation, the second information is carried in a first message, the first message includes a first field, and the first field carries the second information.

[0021] According to the above method, a first field can be newly added to the first message for the second information, so that the second information is transmitted through the first message. For example, the first message can be a message sent by the first central unit to the first distributed unit, so that the first distributed unit of the network device can obtain the second information earlier and schedule resources of the terminal device with reduced capacity earlier.

[0022] According to a second aspect, the present application provides a communication method, the communication method including: a first distributed unit of a network device receiving first information from a terminal device, the first information indicating a type of the terminal device; and the first distributed unit transmitting second information to a first central unit of the network device, the second information indicating a type of the terminal device.

[0023] For example, the central unit of the network device may be a CU, and the distributed unit of the network device may be a DU. According to the aforementioned method, after the terminal device accesses the network device, the first distributed unit of the network device can send second information to the first central unit of the network device based on the first information received from the terminal device, so that the first central unit of the network device can obtain the type of the terminal device in time. For example, the type of the terminal device may be a terminal device of reduced capability (e.g., a REDCAP terminal device, or a NB-IoT terminal device). Alternatively, the type of the terminal device may be a type of a terminal device of moderately reduced capability. For example, if the terminal device of reduced capability is a REDCAP terminal device, the type of the terminal device of reduced capability may be, as another example, a further subdivision terminal device with different capabilities in the REDCAP terminal device, or a further subdivision terminal device of different antennas in the REDCAP terminal device.

[0024] Therefore, in the access process of the terminal device, or when the terminal device is handed over to the first central unit of the network device or the first distributed unit of the network device, the first central unit of the network device can timely control the access of the reduced-capability terminal device based on the type of the terminal device in the second information obtained from the first central unit of the network device, so as to improve the utilization of network resources.

[0025] In a possible embodiment, the first central unit controls the access of the terminal device based on the second information.

[0026] In a possible embodiment, the first central unit transmits the second information to a third distributed unit, which is the distributed unit to which the terminal device is handed over from the first distributed unit.

[0027] In a possible embodiment, the first central unit transmits the second information to a third central unit, which is a central unit to which the terminal device is handed over from the first central unit.

[0028] In a possible embodiment, the second information is used to control the access of the terminal device.

[0029] In a possible implementation, the second information is carried in a second message, the second message including the first field, the first field carrying the second information.

[0030] According to the above method, the first field may be newly added to the second message for the second information, so that the second information is transmitted through the second message. For example, the second message may be an initial uplink radio resource control message transfer message, so that the first central unit of the network device can obtain the second information earlier and control the access of the terminal device with reduced capability earlier.

[0031] In a possible embodiment, the first message is either a downlink radio resource control message transfer message or a terminal device context request message, and the second message is an initial uplink radio resource control message transfer message.

[0032] In a possible embodiment, the first information is carried by message 1 or message 3.

[0033] In the above scheme, after the first information, i.e. after message 1 or message 3 in the random access process, the first distributed unit of the network device or the first central unit of the network device can send information to the corresponding first central unit or first distributed unit earlier to schedule or manage the reduced capacity terminal device earlier.

[0034] In possible implementations, the first distributed unit and the first central unit are separate network elements in a first network device, the first network device being configured for a terminal device to access the network, the second distributed unit and the second central unit are separate network elements in a second network device, the second network device being configured for a terminal device to access the network, the third distributed unit and the third central unit are separate network elements in a third network device, the third network device being configured for a terminal device to access the network, the second distributed unit and the first central unit are separate network elements in a fourth network device, the fourth network device being configured for a terminal device to access the network, or the third distributed unit and the first central unit are separate network elements in a fifth network device, the fifth network device being configured for a terminal device to access the network.

[0035] According to a third aspect, the present application provides a communication device for use in a first central unit of a network device. The first central unit may include a processing module, a transmitting module, and a receiving module.

[0036] The processing module is configured to receive first information from the terminal device via the receiving module, the first information indicating a type of the terminal device. The processing module is configured to transmit second information to a first distributed unit of the network device via the transmitting module, the second information indicating a type of the terminal device. 2 The information indicates the type of terminal device.

[0037] In a possible embodiment, the processing module is adapted to receive the first information from the terminal device via the first distributed unit via the receiving module.

[0038] In a possible embodiment, the processing module is configured to receive the first information from the terminal device via the receiving module via the second distributed unit, the second distributed unit being a distributed unit accessed by the terminal device before the terminal device is handed over to the first distributed unit.

[0039] In a possible embodiment, the processing module is configured to receive, via the receiving module, the first information transmitted by the second central unit, the second central unit being a central unit accessed by the terminal device before the terminal device is handed over to the first central unit.

[0040] In a possible embodiment, the first distribution unit schedules resources of the terminal devices and / or access priorities of the terminal devices based on the second information.

[0041] In a possible implementation, the processing module is configured to transmit the second information to a third distributed unit via the transmitting module, the third distributed unit being a distributed unit to which the terminal device is handed over from the first distributed unit.

[0042] In a possible embodiment, the processing module is configured to transmit the first information to a third central unit via the transmitting module, the third central unit being a central unit to which the terminal device is handed over from the first central unit, and the first information is to be used by the third central unit to transmit the second information to a third distributed unit, the third distributed unit being a distributed unit to which the terminal device is handed over from the first distributed unit.

[0043] In a possible implementation, the second information is carried in a first message, the first message includes a first field, and the first field carries the second information.

[0044] According to a fourth aspect, the present application provides a communication apparatus for use in a first distributed unit of a network device. The first distributed unit may include a processing module, a transmitting module, and a receiving module.

[0045] The processing module is configured to receive first information from the terminal device via the receiving module, the first information indicating a type of the terminal device, and the processing module is configured to transmit second information to a first central unit of the network device via the transmitting module, the second information indicating a type of the terminal device.

[0046] In possible implementations, the type of terminal device includes any one of the following: a reduced capability terminal device or a type of reduced capability terminal device.

[0047] In a possible embodiment, the first central unit controls the access of the terminal device based on the second information.

[0048] In a possible embodiment, the first central unit transmits the second information to a third distributed unit, which is the distributed unit to which the terminal device is handed over from the first distributed unit.

[0049] In a possible embodiment, the first central unit transmits the second information to a third central unit, which is a central unit to which the terminal device is handed over from the first central unit.

[0050] In a possible embodiment, the second information is used to control the access of the terminal device.

[0051] In a possible implementation, the second information is carried in a second message, the second message including the first field, the first field carrying the second information.

[0052] Referring to the third or fourth aspect, the first message is either a downlink radio resource control message transfer message or a terminal device context request message, and the second message is an initial uplink radio resource control message transfer message.

[0053] With reference to the third or fourth aspect, in a possible implementation the first information is carried by message 1 or message 3.

[0054] With reference to the third or fourth aspect, in possible implementations, the first distributed unit and the first central unit are separate network elements in a first network device, the first network device being configured for a terminal device to access the network, or the second distributed unit and the second central unit are separate network elements in a second network device, the second network device being configured for a terminal device to access the network, or the third distributed unit and the third central unit are separate network elements in a third network device, the third network device being configured for a terminal device to access the network, or the second distributed unit and the first central unit are separate network elements in a fourth network device, the fourth network device being configured for a terminal device to access the network, or the third distributed unit and the first central unit are separate network elements in a fifth network device, the fifth network device being configured for a terminal device to access the network.

[0055] According to a fifth aspect, the present application provides a communication device including a processor and a memory. The memory is configured to store computer-executable instructions. When the device is operated, the processor executes the computer-executable instructions stored in the memory, and the device is enabled to perform any of the methods in the implementation of the first aspect.

[0056] According to a sixth aspect, the present application provides a communication device including a processor and a memory. The memory is configured to store computer-executable instructions. When the device is operated, the processor executes the computer-executable instructions stored in the memory, and the device is enabled to perform any of the methods in the implementation method of the second aspect.

[0057] According to a seventh aspect, an embodiment of the present application further provides a computer-readable storage medium, the computer-readable storage medium storing instructions, which, when executed on a computer, enable the computer to perform any of the methods of implementing the first to second aspects.

[0058] According to an eighth aspect, an embodiment of the present application further provides a computer program product, the computer product including a computer program, which, when executed, performs any of the methods in the implementations of the first to second aspects.

[0059] According to a ninth aspect, an embodiment of the present application further provides a chip system including a processor configured to execute any of the methods in the implementations of the first to second aspects.

[0060] According to a tenth aspect, an embodiment of the present application further provides a communication system comprising a first central unit of the third aspect or the fifth aspect, or comprising a first distributed unit of the fourth aspect or the sixth aspect. [Brief description of the drawings]

[0061] [Figure 1] FIG. 1 is a schematic diagram of a network architecture to which an embodiment of the present application is applicable; [Figure 2a] FIG. 1 is a schematic diagram of a network architecture to which an embodiment of the present application is applicable; [Figure 2b] FIG. 1 is a schematic diagram of a network architecture to which an embodiment of the present application is applicable; [Diagram 3] 2 is a schematic flowchart of a random access method. [Figure 4] 1 is a schematic flowchart of a communication method according to an embodiment of the present application. [Diagram 5] 1 is a schematic flowchart of a communication method according to an embodiment of the present application. [Figure 6]1 is a schematic flowchart of a communication method according to an embodiment of the present application. [Figure 7] 1 is a schematic flowchart of a context setting method. [Figure 8] FIG. 1 is a schematic diagram of an application scenario in which an embodiment of the present application is applicable; [Figure 9] 1 is a schematic flowchart of a communication method according to an embodiment of the present application. [Figure 10] FIG. 1 is a schematic diagram of an application scenario in which an embodiment of the present application is applicable; [Figure 11] 1 is a schematic flowchart of a communication method according to an embodiment of the present application. [Figure 12] 1 is a schematic flowchart of a communication method according to an embodiment of the present application. [Figure 13] 1 is a schematic flowchart of a communication method according to an embodiment of the present application. [Figure 14] 1 is a schematic diagram of a communication device according to an embodiment of the present application; [Figure 15] 1 is a schematic diagram of a communication device according to an embodiment of the present application; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0062] The following describes some terms in the embodiments of the present application to help those skilled in the art to understand better.

[0063] (1) A reduced capability terminal device refers to a terminal device having simplified functions designed to improve the battery life of a terminal device in a 5G NR network, including low data processing capability, small signal transmission and reception bandwidth, low battery capacity, and a small number of transmission and reception antennas. For example, a REDCAP terminal device supports a lower air interface capability. For example, a REDCAP terminal device supports a smaller bandwidth, a smaller number of antennas, a lower modulation order, etc., in terms of capability. Specifically, a REDCAP terminal device may be further classified into different REDCAP terminal device types based on the maximum capability supported. For example, a REDCAP terminal device may be classified into a high capability REDCAP terminal device type (e.g., the maximum number of supported receive antennas is 2, or the maximum supported bandwidth is 40M) and a low capability REDCAP terminal device type (e.g., the maximum number of supported receive antennas is 1, or the maximum supported bandwidth is 20M). It should be noted that in this embodiment of the present application, the reduced capability terminal device may alternatively be a narrow band internet of things (NB-IoT) terminal device or a machine type communication (MTC) terminal device, or alternatively may be another type of terminal device with simplified functions. The use of REDCAP as the reduced capability terminal device is only used as an example in this specification. The name of the reduced capability terminal device is not limited in this application.

[0064] (2) The communication system may be various radio access technology (RAT) systems, such as long term evolution (LTE) systems and various LTE evolution-based systems, and may further be applicable to future communication technologies, such as 5th generation (5G) systems and new radio (NR) systems.

[0065] FIG. 1 is a schematic diagram of a network architecture of a communication system to which an embodiment of the present application can be applied.

[0066] 1, the communication system includes a terminal device 101 and a network device 102. The terminal device 101 accesses the network device 102 through a random access process.

[0067] The terminal device 101 can access the wireless network to obtain a service of an external network (e.g., the Internet) through the wireless network or communicate with another device through the wireless network, for example, communicate with another terminal device. The access network may be a next generation radio access network (NG-RAN), and the access network may include access network devices such as base stations (e.g., gNBs). The gNBs are connected to each other through an interface (e.g., an Xn interface). The RAN device is configured to access the wireless network to the terminal device 101, and the gNB is connected to the 5GC through an interface (e.g., an Ng interface). The core network may include multiple core network devices. The core network device is configured to provide a gateway for managing the terminal device and communicating with the external network. If the network architecture shown in FIG. 1 is applicable to a 5G communication system, the core network may be a 5G core network (5GC). The 5GC includes one or more functions or devices. For example, the core network devices may be access and mobility management function (AMF) entities, session management function (SMF) entities or user plane function (UPF) entities, session management functions (SMF), etc. These functions or devices may be network elements in hardware devices, software functions running on dedicated hardware, or virtualization functions instantiated on a platform (such as a cloud platform). It will be understood that the names of the various core network devices are names in the 5G communication system.As communication systems evolve, the names of various core network devices may be replaced with other names having the same functions. When the network architecture shown in Figure 1 is applicable to an LTE communication system, the core network devices may be a mobility management entity (MME), a serving gateway (S-GW), etc.

[0068] It should be understood that the number of devices in the communication system shown in Figure 1 is merely an example, which is not limited in this embodiment of the present application. In practical application, the communication system may further include more terminal devices 101 and more RAN equipment, and may further include other equipment.

[0069] The RAN may also be referred to as an access network device or base station, or may also be referred to as a RAN node (or RAN device). Currently, some examples of access network devices are as follows: gNB / NR-NB, transmission reception point (TRP), evolved Node B (eNB), next generation evolved Node B (ng-eNB), radio network controller (RNC), Node B (Node B, NB), base station controller (BSC), base transceiver station (BTS), home base station (e.g., home evolved NodeB, or home Node B, HNB), base band unit (BBU), wireless fidelity (Wifi) access point (AP), or access network devices in possible future communication systems. Alternatively, the access network device may be a gNB of a 5G system, e.g. an NR system, a transmission point (TRP or TP), one or a group of antenna panels (including multiple antenna panels) of a base station of the 5G system, or a network node forming a gNB or a transmission point, e.g. a baseband unit (BBU).

[0070] The terminal device is Finally,A user equipment (UE), also called a mobile station (MS), mobile terminal (MT), etc., is a device that provides voice or data connectivity to a user and may be an Internet of Things device. For example, a terminal device may include a handheld device or an in-vehicle device with wireless connectivity. At present, the terminal device may be a mobile phone, a tablet computer, a notebook computer, a palmtop computer, a mobile internet device (MID), a wearable device (such as a smart watch, a smart band, a pedometer, etc.), an in-vehicle device (such as an automobile, a bicycle, an electric vehicle, an airplane, a ship, a train, a high-speed rail, etc.), a virtual reality (VR) device, an augmented reality (AR) device, a wireless terminal device in industrial control, a smart home device (such as a refrigerator, a TV, an air conditioner, a meter, etc.), an intelligent robot, a workshop device, a wireless terminal device in self driving, a wireless terminal device in remote medical surgery, a wireless terminal device in a smart grid, a wireless terminal device in transportation safety, a wireless terminal device in a smart city, a wireless terminal device in a smart home, a flying device (such as an intelligent robot, a hot air balloon, a drone, an airplane), etc. In this embodiment of the present application, a UE or terminal device is used to describe the solution.

[0071] 2a is a schematic diagram of a network architecture in a 5G communication system to which an embodiment of the present application can be applied. As shown in FIG. 2a, the network architecture includes a CN device (for example, a 5G CDMA device shown in FIG. 2a), a RAN device, and a terminal device.

[0072] The RAN device and the terminal device comply with a specific protocol layer structure to communicate with each other. For example, the control plane protocol layer structure may include protocol layer functions such as a radio resource control (RRC) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, a media access control (MAC) layer, and a physical layer. The user plane protocol layer structure may include protocol layer functions such as a PDCP layer, an RLC layer, a MAC layer, and a physical layer. In a possible embodiment, a service data adaptation protocol (SDAP) layer may further be included above the PDCP layer. The main function of the RRC layer is to be an upper layer control plane of the UE, which is related to the access control, maintenance, and release of the UE, the configuration of the UE, etc., so that the RRC layer can analyze the RRC messages. The main function of the MAC layer and physical layer (PHY) is the lower layer scheduling of the UE, which is related to the UE's data packaging, data scheduling, etc., so that the MAC layer can analyze the control signaling of the MAC layer, and the PHY layer can analyze the control signaling of the PHY layer. A RAN device may use one node to implement protocol layer functions such as RRC, PDCP, RLC, and MAC, or may use multiple nodes to implement such protocol layer functions.

[0073] In the new network architecture of the 5G NR network, a network device may include two logical network elements: a central unit and a distributed unit. Some functions of the network device are located in one central unit, and the remaining functions are located in the distributed units. Multiple distributed units can share one central unit to reduce costs and facilitate network expansion. Functions may be deployed integrally or separately based on scenarios and requirements. For example, the central unit may be a CU, and the distributed unit may be a DU. The following describes an example in which a network architecture including a central unit and a distributed unit is a CU-DU separated architecture. With the evolution of the network architecture and the emergence of new service scenarios, when the radio access network device in the communication system has an architecture equivalent to the CU-DU separated architecture or the functions of the CU-DU separated architecture, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0074] In this embodiment of the application, the CU and the DU are connected via an interface (e.g., an F1 interface). The CU represents that the base station is connected to the core network via an interface (e.g., an Ng interface). In the communication system of the application, as shown in FIG. 2a, the UE may be connected to an access network device (e.g., a gNB). Specifically, the UE may be connected to a DU in the gNB. The CU is separately connected to the 5GC and the DU. In the downlink communication link, the CU is configured to receive data from the 5GC and transmit the data to the DU. In the uplink communication link, the CU is configured to receive data from the DU and transmit the data to the 5GC. In addition, the CU has a centralized control function for the DU. In systems using different radio access technologies, the device having the CU function may have different names. For ease of explanation, the device having the CU function is collectively referred to as an access network central unit.

[0075] The DU is separately connected to the CU and the user equipment (UE). In the downlink communication link, the DU is configured to receive data from the CU and transmit data to the UE. In the uplink communication link, the DU is configured to receive data from the UE and transmit the data to the CU. In systems using different radio access technologies, devices with DU functionality may have different names. For ease of explanation, devices with DU functionality are collectively referred to as access network distribution units.

[0076] In the above network architecture, the signaling generated by the CU may be sent to the terminal device via the DU, or the signaling generated by the terminal device may be sent to the CU via the DU. The DU can transparently send the signaling to the terminal device or the CU after being directly encapsulated by the protocol layer without parsing. When the following embodiment is involved in such signaling transmission between the DU and the terminal device, in this case, the transmission and reception of the signaling by the DU includes this scenario. For example, the signaling of the RRC layer or the PDCP layer is finally processed as the signaling of the physical layer and sent to the terminal device, or is converted from the received signaling of the physical layer. In this architecture, the signaling of the RRC layer or the PDCP layer can also be considered as being sent by the DU, or being sent by the DU and the radio frequency load.

[0077] The protocol stack-based allocation between the CU of the network device and the DU of the network device can be shown in Figure 2b. For example, the RRC layer, the SDAP layer, and the PDCP layer are located in the CU of the network device. The RLC layer, the MAC layer, and the physical layer are located in the DU of the network device.

[0078] In this embodiment of the present application, if the network device is a device supporting the NR system, the function allocation of the CU and the DU may be performed based on the protocol stack. The CU of the network device and the DU of the network device are used as two functional entities. In one possible manner, the function allocation is performed based on the real-time of content processing. As shown in Figure 2b, the RRC layer, the SDAP layer, and the PDCP layer are disposed in the CU. The RLC layer, the MAC layer, the PHY layer, etc. are deployed in the DU. Correspondingly, the CU has the processing capabilities of RRC, PDCP, and SDAP. For a network device of the CU-DU architecture, the CU of the network device is responsible for managing the RRC state of the terminal device. The DU has the processing capabilities of RLC, MAC, and PHY.

[0079] It should be noted that the above function allocation is only an example, and there may be other allocation methods. For example, the CU includes the processing capabilities of RRC, PDCP, RLC, and SDAP, and the DU has the processing capabilities of MAC and PHY. In another example, the CU includes the processing capabilities of RRC, PDCP, RLC, SDAP, and part of MAC (e.g., MAC packet header is added), and the DU has the processing capabilities of PHY and part of MAC (scheduling, etc.).

[0080] Such allocation at the protocol layer is merely an example. The allocation may also be performed at other protocol layers. For example, the allocation is performed at the RLC layer, and the functions of the RLC layer and the protocol layers above the RLC layer are assigned to the CU, and the functions of the protocol layers below the RLC layer are assigned to the DU. Alternatively, the allocation is performed at the protocol layer. For example, some functions of the RLC layer and the functions of the protocol layers above the RLC layer are assigned to the CU, and the remaining functions of the RLC layer and the functions of the protocol layers below the RLC layer are assigned to the DU. In addition, the allocation may be performed in a different manner. For example, the allocation is performed based on delay, and the functions whose processing time needs to meet the delay constraint are assigned to the DU, and the functions whose processing time does not need to meet the delay constraint are assigned to the CU. The allocation at the protocol layer as described above is merely an example. The allocation may also be performed at other protocol layers that are not described in detail in this specification using examples.

[0081] Of course, this embodiment of the present application may be further applicable to an LTE communication system. For example, the LTE communication system may also include a RAN device and a CN device. The RAN device (eNB) includes a baseband device and a radio frequency device. The baseband device may be implemented using one node, or may be implemented using multiple nodes. The radio frequency device may be implemented independently and remotely from the baseband device, or may be integrated into the baseband device, or a part is remote and a part is integrated into the baseband device. The radio frequency device may be remotely located with respect to the baseband device, for example, a remote radio unit (RRU) is remotely located with respect to the BBU. Furthermore, the radio frequency device may be remotely located without being located in the DU, or may be integrated into the DU, or a part is remote and a part is integrated into the DU. This is not limited in this specification.

[0082] It should be understood that the number and type of UEs included in the communication system shown in Figures 2a and 2b are only an example. This is not limited in this embodiment of the present application. For example, more UEs communicating with an access network device (such as a gNB) may be included. For brevity, this is not described in detail in the accompanying drawings. Also, in the communication system shown in Figures 2a and 2b, one base station and one UE connected to each DU are shown, but the communication system may not be limited to including a base station and a UE connected to each DU. Details will not be repeated in this specification.

[0083] In the following embodiments of this specification, it is mainly used as an example that the network supported by the first DU is the union set of networks supported by all logical CUs, i.e., the first DU supports the networks supported by each logical CU connected to the first DU. For ease of explanation, in the following description of this specification, the first logical CU is shortly referred to as "first CU", and in the following description, the second logical CU is shortly referred to as "second CU".

[0084] It should be understood that Figures 1 to 2b only show some functions or devices in the embodiments of the present application, and the communication system architecture may further include more or less functions or devices. For example, the 5GC device in Figure 1 may further include a unified data management (UDM), a data network (DN), etc. The DU shown in Figure 2a or Figure 2b may further be configured with more logical cells, etc.

[0085] The communication system architecture to which the embodiments of the present application are applicable is not limited to those shown in Figures 1 to 2b. The present application is applicable to all communication system architectures capable of implementing the functions of the devices shown in Figures 1 to 2b.

[0086] The terms "system" and "network" may be used interchangeably in the embodiments of this application. "At least one" means one or more, and "multiple" means two or more. The term "and / or" describes an association relationship to describe associated objects and represents that three relationships may exist. For example, A and / or B may represent the following three cases: only A is present, both A and B are present, and only B is present, where A and B may be singular or plural. The character " / " generally indicates an "or" relationship between associated objects. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of singular items or multiple items. For example, at least one of a, b, or c may represent a, b, c, a and b, a and c, b and c, or a, b, and c.

[0087] Furthermore, unless otherwise specified, ordinals such as "first" and "second" referred to in the embodiments of the present application are used to distinguish between multiple objects, and are not intended to limit the order, chronology, priority, or importance of the multiple objects. For example, a first priority criterion and a second priority criterion are merely used to distinguish between different criteria, and do not indicate that the content, priority, or importance of the two criteria are different.

[0088] Furthermore, the terms "including" and "having" in the embodiments, claims, and accompanying drawings of this application are not exclusive. For example, a process, method, system, product, or device that includes a series of steps or modules is not limited to the recited steps or modules, and may further include unrecited steps or modules.

[0089] In the network architecture shown in Figure 1, Figure 2a or Figure 2b, the terminal device 101 performs a normal service transmission to set up a connection to the network device 102 and request the network device 102 to allocate corresponding dedicated resources to the terminal device 101. The terminal device can set up uplink synchronization with the network device via a random access process and obtain a unique terminal device identifier, for example a cell radio network temporary identifier (C-RNTI), so that the terminal device can perform uplink transmission with the network device.

[0090] The following describes relevant technical features of the random access process in the embodiments of the present application.

[0091] 1. Triggering the Random Access Process The random access process refers to a process from when a terminal device starts to attempt to access a network by transmitting a random access signal to when a basic signaling connection to a network device is set up. The random access signal may be used to initiate the random access process. For example, the random access signal may be a random access preamble. Optionally, the random access signal may alternatively be a demodulation reference signal (DMRS). The terminal device may exchange information with the network device through the random access process to implement uplink time synchronization with the communication system. Optionally, the terminal device may further perform resource request or data transmission through the random access process. In this embodiment of the present application, the random access process may also be referred to as random access, random access channel process, or random access method. This is not distinguished in the present application and may be used interchangeably in the following description.

[0092] For example, there may be multiple events (or scenarios) that trigger the random access process. For example, in an LTE communication system, the random access process may be triggered in the following scenarios:

[0093] Scenario 1: In the initial access of a terminal device, the terminal device sets up an initial RRC connection. When the RRC idle (RRC_IDLE) state is changed to an RRC connected (RRC_CONNECTED) state, the terminal device initiates random access.

[0094] Scenario 2: The terminal device re-establishes an RRC connection (RRC connection re-establishment procedure) When the terminal device needs to re-establish an RRC connection after a radio connection failure, the terminal device initiates a random access.

[0095] Scenario 3: When a terminal device performs a cell handover, the terminal device initiates random access in the target cell.

[0096] Scenario 4: Downlink data arrives. When the terminal device is in a connected state, the network device needs to transmit downlink data to the terminal device, but finds that the terminal device is out of uplink synchronization. That is, in the RRC_CONNECTED state, when downlink data arrives (in this case, an ACK / NACK response is required), the uplink is in an "out of sync" state. The network device controls the terminal device to start random access. The network device side maintains an uplink timer. If the uplink timer expires and the network device does not receive a response signal from the terminal device, the network device considers that the terminal device is out of uplink synchronization.

[0097] Scenario 5: Uplink data arrives. When the terminal device is in a connected state, the terminal device needs to transmit uplink data to the network device, but discovers that the terminal device is out of uplink synchronization. That is, in the RRC_CONNECTED state, when uplink data arrives (e.g., measurement reports need to be reported or user data needs to be transmitted), the uplink is in an "out of sync" state or there are no physical uplink control channel (PUCCH) resources available for a scheduling request (SR) transmission (in this case, a terminal device in uplink synchronization is allowed to use a random access channel (RACH) to replace the SR). In this case, the terminal device initiates random access. The terminal device side maintains an uplink timer. If the uplink timer expires and the terminal device does not receive a command by the network device to adjust the maximum time advanced (TA) value, the terminal device considers the uplink to be out of synchronization.

[0098] As another example, in a 5G communication system, the random access process may be further triggered in the following scenarios:

[0099] (1) Uplink (UL) data arrives in an Inactive state, in which case the uplink is "out of sync". (2) Downlink (DL) data arrives in an Inactive state, in which case the uplink is "out of sync". (3) On-demand system information (SI) is requested (in a 5G communication system, system information is classified into two types: minimum SI and on-demand SI, where minimum SI must be accepted by all terminal devices and on-demand SI may be requested according to the request of the terminal device). (4) Beam failure recovery (BFR).

[0100] The above are events that trigger the random access process. It can be seen that regardless of the LTE system or the NR system, the terminal device needs to access the network device through a random access process. There are two different methods of the random access process: contention-based random access and non-contention-based random access. For example, depending on whether the preamble transmitted by the terminal device is selected by the terminal device, the random access process can be classified into a contention-based random access process and a non-contention-based random access process. In the contention-based random access process, the preamble can be selected by the terminal device. If the event that triggers the random access process is an event other than the handover and beam failure recovery described above, the contention-based random access process may be used. In the non-contention-based random access process, the preamble may be assigned to the terminal device by the network device. If the event that triggers the random access process is the handover or beam failure recovery event described above, the non-contention-based random access process may be used.

[0101] In the following, a contention-based random access process is used as an example to describe several steps involved in the random access process with reference to Fig. 3. Fig. 3 is a schematic diagram of a random access process according to an embodiment of the present application. As shown in Fig. 3, the image processing method provided in this embodiment of the present application includes the following steps:

[0102] Step 300: When the network device sends random access configuration information to the terminal device, the terminal device can receive the random access configuration information from the network device, and the random access configuration information is used to configure random access parameters. This step may be a preparation before the random access process is performed, and is not a step included in the random access process.

[0103] For example, the random access parameters may include one or more of a physical random access channel (PRACH) resource set used to transmit the random access preamble, a random access preamble set, a maximum number of transmissions of the random access preamble, an initial transmission power of the random access preamble, a size of a random access response window, a maximum number of hybrid automatic repeat request (HARQ) repetitions of the third message, and a duration of a contention resolution timer. Additionally, the random access parameters may further include a power ramping step.

[0104] The PRACH resource set may include time-frequency resources that may be used by the terminal device to transmit the preamble and may be indicated by a field rach-ConfigGeneric. The maximum number of transmissions of the random access preamble may be indicated by a field totalNumberOfRA-Preambles. The initial transmission power of the random access preamble may be indicated by a field reambleInitialReceivedTargetpower. The size of the random access response window indicates the number of subframes included in the random access response window and may be indicated by a field ra-ResponsewindowSize. The random access response window starts with the third subframe after the subframe in which the terminal device transmits the preamble (if the preamble spans multiple subframes in the time domain, the last subframe is used as the start of the count) and lasts for ra-ResponseWindowSize subframes. The maximum number of HARQ repetitions of the third message may be indicated by a field maxHARQ-Msg3. The duration of the contention resolution timer may be indicated by a field mac-ContentionResolutionTimer.

[0105] (1) It should be noted that for each of the above "PRACH resource set, preamble set, maximum number of transmissions of random access preamble, initial transmission power of random access preamble, size of random access response window, maximum number of HARQ repetitions of the third message, and duration of contention resolution timer", corresponding default values ​​may be set. For example, when the random access configuration information transmitted by the network device is PWhen a RACH resource set is configured but not configured with a maximum number of transmissions of a random access preamble (e.g., the random access configuration information includes the field rach-ConfigGeneric but does not include the field totalNumberOfRA-Preambles), the value of the maximum number of transmissions of a random access preamble may be a default value.

[0106] (2) The above describes an example of the contents included in the random access parameters. In another possible embodiment, the random access parameters may further include other contents related to the random access process, such as time indication information.

[0107] Step 301: A terminal device sends a preamble to a network device, and the network device receives a preamble from the terminal device, where the preamble is also called a first message or message 1 (MSG1) in a random access process.

[0108] The preamble sent by the terminal device to the network device in step 301 may be a random access request sent by the terminal device to the network device. The preamble may be a preamble selected by the terminal device from the preamble set obtained in step 300 for random access. Optionally, the network device may estimate a transmission delay between the network device and the terminal device based on the preamble, and calibrate uplink timing based on the transmission delay.

[0109] Step 302: After detecting the preamble sent by the terminal device, the network device sends a random access response (RAR) message to the terminal device.

[0110] Correspondingly, the terminal device receives an RAR message from the network device. The RAR message is also referred to as the second message or message 2 (MSG2) in the random access process. The message 2 includes a MAC Protocol Data Unit (PDU) including a media access control MAC subheader and a MAC RAR. The message 2 may include the following information: an identifier or index of the detected preamble, uplink time synchronization information, and one or more types of uplink resources and BIs allocated to the terminal device for transmitting the message 3. Of course, the message 2 may further include other information. The identifier of the preamble is, for example, a random access preamble identifier (RAPID). It should be noted that if the network device does not receive the preamble transmitted by the terminal device, the message 2 transmitted by the network device does not include an identifier of the preamble corresponding to the terminal device.

[0111] For example, the MAC RAR may include a command for timing advance (TA), which is used to specify a time adjustment value required for uplink synchronization of the terminal device, or may further include the uplink resources allocated to the message 3, or may further include a temporary cell radio network temporary identifier (TC-RNTI) allocated to the terminal device, which is used for subsequent transmissions between the terminal device and the network device, and after the contention is resolved, the TC-RNTI may become the cell radio network temporary identifier (C-RNTI).

[0112] After sending message 1, the terminal device receives message 2 in the RAR time window. If message 2 returned by the network device is not received in the RAR time window, the random access process is considered to have failed. For a terminal device that fails the random access, the network device can send a back-off instruction to the terminal device. The back-off instruction can indicate a time value, which is used to determine a back-off time range. If the random access process fails, the terminal device can select a back-off time within the back-off time range, and the random access resource configured by the network device for the terminal device in step 300 cannot be used again until the selected back-off time expires.

[0113] Step 303: The terminal device sends uplink data to the network device based on the message 2.

[0114] In response, the network device receives uplink data from the terminal device, also referred to as a third message or message 3 (MSG3) in the random access process.

[0115] The message 3 may include identifiers of different scenario information, and the identifiers are used for contention resolution in step 304. The message 3 may have different contents based on different states of the terminal device and different application scenarios. As an example, an identifier of the terminal device (e.g., UE-ID) is used. For example, in an initial access scenario, the message 3 is an RRC Setup Request message. In this case, the message 3 carries a unique identifier or a random number of the terminal device. In a scenario in which the terminal device reestablishes an RRC connection, the message 3 is an RRC Reestablishment Request message, and the identifier of the corresponding scenario information is C-RNTI. For an RRC connection resumption scenario, the message 3 is an RRC Resume Request message, and the identifier of the corresponding scenario information may be C-RNTI. In another scenario in which the terminal device is in an RRC connected state, the unique identifier of the terminal device carried in the message 3 may be C-RNTI. For example, the message 2 may carry an uplink resource and a TA command. In this way, after receiving message 2, the terminal device transmits message 3 on the uplink resource indicated by message 2 using the TA value indicated by the TA command.

[0116] Step 304: Upon detecting message 3, the network device sends a contention resolution message to the terminal device, and the terminal device receives the contention resolution message from the network device.

[0117] The contention resolution message is also referred to as the fourth message or message 4 (MSG4). Message 4 may include part of the content of message 3 or a physical downlink control channel (PDCCH) containing the C-RNTI, i.e., message 4 includes the C-RNTI carried by the PDCCH.

[0118] Message 4 is used for conflict resolution. In the conflict resolution mechanism, the network device includes a unique identifier in message 4 (message 3 includes the unique identifier of the terminal device) to specify the terminal device that successfully accessed the network, and another terminal device that failed in conflict resolution will start random access again.

[0119] For example, if the network device receives uplink data sent by the terminal device, the message 4 may carry an identifier of the terminal device. If the network device does not receive uplink data sent by the terminal device, the message 4 sent by the network device does not include an identifier of the terminal device. Upon receiving the message 4, the terminal device can determine whether the terminal device has successfully accessed the network device according to whether the identifier of the terminal device carried in the message 4 matches the identifier of the terminal device itself. If the two identifiers match, it is determined that the terminal device has successfully accessed the network device, or if the two identifiers do not match, it is determined that the terminal device cannot access the network device.

[0120] Optionally, after message 4, message 5 may be further included, which is sent by the terminal device to the network device. Message 5 may be used to send capability information of the terminal device. For a specific manner, please refer to the following FIG. 7. Details are not repeated in this specification.

[0121] It should be noted that the above describes the implementation process of the contention-based random access process and provides a reference for the implementation of the non-contention-based random access process. Unlike the contention-based random access process, for the non-contention-based random access process, the random access parameters may further include powerRampingStepHighPriority and scalingFactorBI in addition to the above parameters.

[0122] As an example, a 5G communication system is used. The terminal device may be some special terminal devices, such as a REDCAP terminal device, an NB-IoT terminal device, or an MTC terminal device. Resources and access methods need to be correspondingly allocated to these reduced-capability terminal devices to meet the requirements of narrow bandwidth and low power consumption of the reduced-capability terminal devices. Based on this, when such a device accesses a network device, the network device needs to know as early as possible whether the accessed terminal device is a reduced-capability terminal device, so that the access network device can schedule corresponding resources for the reduced-capability terminal device earlier or perform access control for the reduced-capability terminal device.

[0123] Based on the above architecture, an embodiment of the present application provides a communication method for implementing an access procedure of a terminal device after the above architecture provided in the embodiment of the present application is applied. As shown in Figure 4, the method may include the following steps:

[0124] Step 401: A first unit of a network device obtains first information from a terminal device.

[0125] In some embodiments, the first unit may be the DU of the network device, and the second unit may be the CU of the network device. In this case, the network device may obtain the first information based on the first information transmitted by the terminal device. Alternatively, the first unit may be the CU of the network device, and the second unit may be the DU of the network device. In this case, the network device may receive the first information from the terminal device via the DU of the network device. In some other embodiments, the first unit may be the target DU of the network device, and the second unit may be the target CU of the network device. That is, the terminal is handed over from the source CU to the target CU and from the source DU to the target DU based on reasons such as movement. In this case, the first unit may be the target DU of the network device. Thus, the CU of the network device may transmit the first information from the terminal device to the target DU of the network device in the handover process, so that the target DU of the network device obtains the first information from the terminal device. Alternatively, the CU is not changed, and the terminal device is handed over from the source DU to the target DU. In this case, the first unit may be the target DU of the network device, and the second unit may be the target CU of the network device. Therefore, in the handover process, the network device can first send first information from the terminal device to the target CU of the network device via the source CU of the network device, and then send the first information from the terminal device to the target DU of the network device via the target CU of the network device, so that the target DU of the network device obtains the first information from the terminal device.

[0126] The first information indicates a type of the terminal device, and the type of the terminal device includes: the terminal device is a reduced capability terminal device, or the type of the terminal device is a reduced capability terminal device type.

[0127] For specific instruction methods, please refer to the following methods 1 to 3. Details will not be repeated in this specification.

[0128] Step 402: The first unit of the network device sends second information to the second unit of the network device.

[0129] The second information indicates a type of the terminal device, and the type of the terminal device includes: the terminal device is a reduced capability terminal device, or the type of the terminal device is a reduced capability terminal device type.

[0130] In some embodiments, the second information indicates that the terminal device is a reduced capability terminal device. For example, the second information may identify a type of the terminal device based on an identifier of the terminal device. For example, the second information is an identifier of the terminal device, and identifier=0 indicates that the terminal device has no type configured. Identifier=1 indicates that the terminal device is a REDCAP terminal device. Identifier=2 indicates that the terminal device is an NB-IoT terminal device. Identifiers=3 to 10 are reserved for future use. Identifier=11 indicates that the terminal device is a terminal device corresponding to access class 11, and so on.

[0131] In another example, the second information may further indicate that the terminal device is a terminal device of reduced capability whose maximum number of supported receiving antennas is 2, or may indicate that the terminal device is a terminal device of reduced capability whose maximum number of supported receiving antennas is 1, or may indicate that the terminal device is a terminal device of reduced capability whose maximum supported bandwidth is 40M, or may indicate that the terminal device is a terminal device of reduced capability whose maximum supported bandwidth is 20M, etc. Specifically, the second information may be further classified based on the identifier of the terminal device. For details, please refer to the above example.

[0132] In some other embodiments, the second information may indicate a type of terminal device with reduced capabilities. Compared with the scheme in which the second information indicates a terminal device with reduced capabilities, when the second information indicates a type of terminal device with reduced capabilities, more bits may be set correspondingly. For example, the type of the terminal device with reduced capabilities may be a type such as a terminal device with reduced capabilities having two receiving antennas or a terminal device with reduced capabilities having one receiving antenna. In this case, the type of the terminal device with reduced capabilities may be indicated by 2 bits of the second information. For example, 00 of the second information indicates a terminal device with high capabilities, 11 of the second information indicates a terminal device with reduced capabilities having two receiving antennas, and 01 of the second information indicates a terminal device with reduced capabilities having one receiving antenna.

[0133] According to the aforementioned method, after obtaining the first information from the terminal device, the CU of the network device or the DU of the network device can share information regarding whether the terminal device is a reduced-capability terminal device, so that the CU of the network device can perform access control in time for the accessed reduced-capability terminal device, and the DU of the network device can properly schedule resources of the accessed reduced-capability terminal device in time or properly assign access priorities of the reduced-capability terminal device, so as to implement earlier and more timely management of the reduced-capability terminal device, and optimize network performance of the reduced-capability terminal device.

[0134] In the following, a specific example is used to explain the solution in this embodiment of the present application.

[0135] Example 1 Based on the above architecture, an embodiment of the present application provides a communication method for implementing an access procedure of a terminal device after the above architecture provided in the embodiment of the present application is applied. As shown in Figure 5, the method may include the following steps:

[0136] Step 501: A terminal device sends first information to a first DU.

[0137] The first information indicates a type of the terminal device, and the type of the terminal device includes: the terminal device is a reduced capability terminal device, or the type of the terminal device is a reduced capability terminal device type.

[0138] In some embodiments, when accessing a network device, the terminal device may send the first information to the DU of the network device through message 1 or message 3 in the random access process. Correspondingly, the DU of the network device receives the first information sent by the terminal device through message 1 or message 3 in the random access process, so that the type of the UE can be identified.

[0139] Scheme 1 and scheme 2, in which a DU of a network device receives first information sent by a UE via message 1 or message 3 in a random access process, are described below with the aid of an example.

[0140] Scheme 1: The first information is determined based on the resource information carried in message 1.

[0141] Alternatively, the first information is determined based on resource information corresponding to message 1.

[0142] For example, considering that a specific PRACH time-frequency resource or a specific preamble codeword sequence is configured for a terminal device of reduced capability, after the terminal device selects the specific time-frequency resource or the specific codeword sequence, the terminal device can transmit the corresponding time-frequency resource or codeword sequence via message 1, so that the DU of the network device can use the time-frequency resource or codeword sequence transmitted via message 1 as first information, and the DU of the network device determines that the terminal device is a terminal device of reduced capability based on the time-frequency resource or codeword sequence of the terminal device.

[0143] In another example, considering that a specific initial bandwidth part (BWP) is configured for a terminal device of reduced capability, after the terminal device selects the specific initial BWP, the terminal device transmits message 1 via a time-frequency resource or codeword sequence corresponding to the specific initial BWP, so that the DU of the network device can use the initial BWP corresponding to message 1 as the first information to determine that the UE is a terminal device of reduced capability.

[0144] In the first method, the first information is determined based on the information about the PHY layer. Therefore, the DU having the PHY layer can obtain the first information to determine that the terminal device is a terminal device with reduced capability.

[0145] According to the scheme 1, the base station can better schedule the subsequent messages 2, 3, 4, and subsequent messages. In addition, according to the scheme 1, the base station can perform priority processing for the access of the non-reduced capability terminal device and the REDCAP UE, for example, the non-reduced capability terminal device is preferentially accessed. Alternatively, if the base station is a base station that preferentially configures corresponding resources for the reduced capability UE, the REDCAP UE is preferentially allowed to access the network. Therefore, it may be further set that the random access process initiated by the reduced capability terminal device and the random access process triggered by the handover event (or BFR event) may have the same priority or different priorities.

[0146] Scheme 2: The first information is carried using the second field of message 1 or message 3 in the random access process.

[0147] The second field may be introduced into message 1 or message 3. For example, the second field may be a MAC control element (MAC CE), or the second field may be a new logical channel ID (LCID) field in the MAC subheader. The second field may include the first information.

[0148] In some embodiments, the terminal device may include the first information in the second field, for example, information about REDCAP and type information about REDCAP are included to indicate that the terminal device is a REDCAP UE. In another example, the terminal device may include the first information in the second field to indicate the type of the terminal device, for example, the terminal device is indicated to be a default terminal device, or the terminal device is indicated to be a terminal device for sending an emergency message.

[0149] In the method 2, the first information is determined based on the information on the MAC layer. Thus, the DU with the MAC layer can obtain the information to determine that the terminal device is a terminal device with reduced capabilities. According to the method 2, the base station can better schedule the subsequent message 4 and the subsequent messages. In addition, the base station can perform priority processing for the access of the common UE and the REDCAP UE. For example, the terminal device with non-reduced capabilities is accessed preferentially. In another example, the base station can further better schedule the contention problem between the terminal device with reduced capabilities and the terminal device with non-reduced capabilities.

[0150] Similarly, in the two-step non-contention based random access process, the base station can determine that the terminal device is a reduced capability terminal device based on the message A in the random access process (the message A in the two-step random access process includes the message 1 and the message 3 in the four-step random access process, i.e., the message A is a message combining the message 1 and the message 3). For specific methods, please refer to the above-mentioned method 1 to method 2. Details will not be repeated in this specification.

[0151] Step 502: A first DU of the network device sends a second message to a first CU of the network device.

[0152] The second message includes second information, the second information indicating a type of the terminal device, the type of the terminal device including: the terminal device is a reduced capability terminal device or the terminal device is a type of a reduced capability terminal device.

[0153] Specifically, the second message may be an initial uplink RRC message transfer message. The second message may include a newly added first field, where the first field indicates the second information.

[0154] Table 1 shows the initial uplink RRC message transmission. message1 shows fields that may be included in the RRC set message (RRC-Container), including, for example, a message type field (Message Type), a DU UE F1 interface application identifier field (gNB-DU UE F1AP ID), a NR configured grant information field (NR (configured grant information, CGI)), a terminal device identifier field C-RNTI used by the terminal device to locate the DU of the network device, an RRC container field (RRC-Container) that may include an uplink message field (UL-CCCH-Message IE or UL-CCCH 1-Message IE), a DU to CU RRC container field (DU to CU RRC-Container), a SUL access indication field (Access Indication), a transaction identifier field (Transaction ID), a RAN UE identifier field (RAN UE ID), an RRC container set field (RRC-Container-RRCSetupComplete) carrying an uplink control information element (UL-DCCH-Message IE) in an RRC set message (RRCSetupComplete message), and a terminal device type field (UE type).

[0155] [Table 1A] [Table 1B]

[0156] For example, as shown in Table 2, the first field may indicate a type of terminal device (UE type), and the second information of the first field may include any one of REDCAP, a type of REDCAP, or another UE type.

[0157] For example, the identifier of the terminal device can be used to identify the type of the terminal device. For example, identifier=0 indicates that the terminal device has no type configured. Identifier=1 indicates that the terminal device is a REDCAP terminal device. Identifier=2 indicates that the terminal device is an NB-IoT terminal device. Identifiers=3 to 10 are reserved for future use. Identifier=11 indicates that the terminal device is a terminal device corresponding to access class 11, and so on.

[0158] In this embodiment of the present application, the type information can indicate the type of the terminal device in multiple ways. In one example, the type information can include 4 bits, and the UE type has a total of 16 values. For example, when the value of the 4 bits is 0000, it indicates that the UE type=0, which corresponds to the type of the terminal device, for example, a high-capability terminal device with four antennas. When the value of the 4 bits is 0001, it indicates that the UE type=1, which corresponds to the type of the terminal device, for example, a reduced-capability terminal device with one antenna. When the value of the 4 bits is 0010, it indicates that the UE type=2, which corresponds to the type of the terminal device, for example, a reduced-capability terminal device with two antennas, etc. In this way, the second network device can determine the type of the terminal device based on the UE type indicated by the type information. For example, when the UE type=1, the terminal device can be determined to be a first type of terminal device. In yet another example, the type information may include 1 bit. When the value of the bit is 1, it indicates that the terminal device is a first type of terminal device. If the value of the bit is 0, it indicates that the terminal device is not a first type of terminal device. In yet another example, considering that the terminal device in this embodiment of the present application can be a REDCAP terminal device or a NB-IoT terminal device, the type information can include two bits, and the value of one bit is used to indicate whether the terminal device is a REDCAP terminal device (for example, if the value is 1, it indicates that the terminal device is a REDCAP terminal device, or if the value is 0, it indicates that the terminal device is not a REDCAP terminal device), and the other bit is used to indicate whether the terminal device is an NB-IoT terminal device (for example, if the value is 1, it indicates that the terminal device is an NB-IoT terminal device, or if the value is 0, it indicates that the terminal device is not a NB-IoT terminal device).Alternatively, the type information may include two bits, and the values ​​of the two bits are used together to indicate the type of the terminal device, for example, 00 indicates that the terminal device is a REDCAP terminal device, 01 indicates that the terminal device is an NB-IoT terminal device, 10 indicates that the terminal device is neither a REDCAP terminal device nor an NB-IoT terminal device, and 11 is reserved for future use.

[0159] [Table 2]

[0160] It should be noted that in this embodiment of the present application, the second message may alternatively be a message sent by another DU to the CU in a random access process. For example, the second message is a newly added message and is used to carry the first field, so that the DU can send the second message to the CU to inform the CU whether the terminal device is a reduced capability terminal device.

[0161] Step 503: The first CU may control the terminal device to access the network based on the second information.

[0162] For example, if the CU of the network device determines that the current network load is heavy, the first CU of the network device can deny the access of the terminal device with reduced capabilities. Alternatively, if the first CU of the network device determines that the current network resource is robust, the first CU of the network device can allow the access of the terminal device with reduced capabilities. It should be noted that step 503 is an optional step.

[0163] Example 2 Based on the above architecture, an embodiment of the present application provides a communication method for implementing an access procedure of a terminal device after the above architecture provided in the embodiment of the present application is applied. As shown in Figure 6, the method may include the following steps:

[0164] Step 601: A terminal device sends first information to a first CU of a network device through a first DU of the network device.

[0165] The first information indicates a type of the terminal device, and the type of the terminal device includes: the terminal device is a REDCAP terminal device, or the type of the terminal device is a reduced capability terminal device type.

[0166] In some embodiments, when accessing the network device, the terminal device may send the first information to the CU of the network device through message 3 in a random access process via the DU of the network device. Specifically, the DU of the network device first receives the message 3 sent by the UE, but does not analyze the content of the RRC message in the message 3, and sends the RRC message in the message 3 to the CU of the network device. Correspondingly, the CU of the network device receives the first information sent by the terminal device through message 3 in the random access process, so that the type of the UE can be identified.

[0167] A method 3 in which a CU of a network device receives the first information sent by a UE via a message 3 in a random access process is described below by way of an example.

[0168] Method 3: The terminal device is determined to be a reduced capability terminal device based on an RRC message in message 3 in the random access process.

[0169] In some embodiments, the terminal device may use a reserved field in an RRC message (e.g., an RRC Setup Request message) carried in message 3 as the first field. In other words, the RRC message carried in message 3 includes a first field. The first field includes first information and is used to indicate whether the UE is a REDCAP UE.

[0170] In some other embodiments, the terminal device may extend the size of the RRC message carried in message 3. For example, a newly added field in the RRC message is used as the first field. In other words, the RRC message carried in message 3 includes a first field. The first field includes first information and is used to indicate whether the UE is a REDCAP UE.

[0171] In some other embodiments, the terminal device may introduce a new common control channel and a new RRC message as the RRC message of message 3. The new RRC message includes a first field, where the first field includes first information and is used to indicate whether the UE is a REDCAP UE.

[0172] According to the scheme 3, the base station can control the access of the REDCAP UE earlier. For example, the REDCAP UE is denied access to the network when the network resources are insufficient. In another example, the REDCAP UE is allowed to access the network when the network resources are robust.

[0173] Considering that the information identified in the third method is information about the RRC layer, only the CU with the RRC layer can obtain the information and determine that the terminal device is a terminal device with reduced capabilities. The DU with the PHY layer and the MAC layer does not know the identity information of the REDCAP UE, and cannot properly schedule subsequent messages or perform priority processing for the access of the UE.

[0174] Similarly, in the two-step non-contention-based random access process, the base station can determine that the terminal device is a reduced capability terminal device based on the message A in the random access process (the message A in the two-step random access process includes the message 1 and the message 3 in the four-step random access process, that is, the message A is a message combining the message 1 and the message 3). For a specific method, please refer to the above-mentioned method 3. Details will not be repeated in this specification.

[0175] Step 602: A first CU of a network device sends a first message to a first DU of the network device.

[0176] The first message includes second information, the second information indicating a type of the UE, and the type of the terminal device including that the terminal device is a REDCAP terminal device.

[0177] In some embodiments, the first message may be a DL RRC message transfer message sent by a CU of the network device to a DU of the network device, in which case the first message may include a newly added first field, where the first field carries the second information.

[0178] Table 3 shows fields that may be included in the downlink RRC message transfer message, such as a message type field (Message Type), a CU UE F1 interface application identifier field (gNB-CU UE F1AP ID), a DU UE F1 interface application identifier field (gNB-DU UE F1AP ID), an old DU UE F1 interface application identifier field (old gNB-DU UE F1AP ID) used when the RRC container contains information about the RRC connection setup, a new DU UE F1 interface application identifier field ( new The RRC DU field includes a gNB-DU UE F1AP ID, an SRB identifier field (SRB ID), an Execute Duplication field, an RRC container field (RRC-Container) which may include a downlink message field (DL-DCCH-Message IE), a RAT frequency priority information field (RAT-Frequency Priority Information), an RRC Delivery Status Request field (RRC Delivery Status Request), a terminal device context not retrievable field (UE Context not retrievable), a redirected RRC message field (redirected RRC message), a field of PLMN Assistance Info for Network Sharing, and a first field, for example, a terminal device type field (UE type).

[0179] [Table 3A] [Table 3B]

[0180] For example, referring to Table 3 and Table 2, the first field carried in the first message may be used to indicate the type of the terminal device (UE type), and the value range of the first field may include REDCAP, a type of REDCAP, or another UE type. For example, the identifier of the terminal device may be used to identify the type of the terminal device, and identifier=0 indicates that the terminal device is not configured with a parameter. Identifier=1 indicates that the terminal device is a REDCAP terminal device. Identifier=2 indicates that the terminal device is an NB-IoT terminal device. Identifiers=3 to 10 are reserved for future use. Identifier=11 indicates that the terminal device is a terminal device corresponding to access class 11, and so on. Indeed, the manner of setting the type of the terminal device in the above example may also be referred to. For example, the correspondingly set type of reduced capability terminal device includes a reduced capability terminal device with two antennas with corresponding identifier=3 and a reduced capability terminal device with one antenna with corresponding identifier=4. Details are not repeated in this specification.

[0181] In some other embodiments, the first message may alternatively be a UE context setup request message, in which case a first field may be newly added to the UE context setup request message, such that the first field carries the second information and is used to indicate whether the terminal device is a reduced capability terminal device.

[0182] It should be noted that in this embodiment of the present application, the first message may alternatively be a message sent to the DU by another CU in the random access process or a newly added message used to carry the first field, so that the CU can send the first message to the DU to inform the DU whether the terminal device is a reduced capability terminal device.

[0183] Step 603: The first DU may schedule a subsequent random access message or another message for the reduced capability terminal device based on the second information.

[0184] It should be noted that step 603 is an optional step. For example, the first DU of the network device schedules the subsequent message 4 or message 5 within the capability range of the reduced capability terminal device. Specifically, the first DU can configure corresponding resources for the reduced capability terminal device. For specific configured resources, please refer to the description of the random access process in Figure 4. Details will not be repeated in this specification.

[0185] Optionally, the first CU of the network device may determine, based on the second information, an access priority of the reduced capability terminal device for the reduced capability terminal device.

[0186] For example, the first CU of the network device sets the access priority of the terminal device with reduced capabilities to a low priority, and sets the access priority of the terminal device with non-reduced capabilities to a low priority. expensive A priority order can be set so that when a terminal device with reduced capabilities and a terminal device with non-reduced capabilities access the network at the same time, the terminal device with non-reduced capabilities has priority to access the network.

[0187] After the aforementioned access procedure of the terminal device is completed, the terminal device may need to be further handed over due to poor signal quality of the current cell caused by the movement of the terminal device, or congestion due to the base station currently accessing a large number of terminal devices. The CU of the network device can initiate the handover procedure based on the stored context of the terminal device in the handover process to ensure that the terminal device can set up the RRC connection without re-initiating the random access process, thereby reducing delay and reducing signaling overhead. In addition, a new RRC state is considered: in the inactive state, the RRC connection between the terminal device and the network is interrupted to achieve the same power saving effect as in the idle state. Unlike the idle state, in the inactive state, the terminal device and the access network device store the context of the terminal device. When the terminal device needs to enter the connected state, for example, when the terminal device has uplink data to send or when the network device pages the terminal device to enter the connected state, the terminal device enters the connected state based on the stored context of the terminal device, thereby reducing delay and reducing signaling overhead. The following uses an example to describe the context setting procedure of the terminal device, for details, see Figure 7.

[0188] Step 701: The terminal device sends capability information to the CU of the network device.

[0189] The capability information indicates the capabilities of the terminal device.

[0190] Optionally, the capability information indicates that the terminal device has the capability of transmitting data in an inactive state, and the capability indicates that the terminal device has the capability of transmitting uplink information in a configured grant or a scheduling grant in an inactive state. The uplink information includes, but is not limited to, uplink signaling and uplink data. The uplink signaling may be uplink RRC signaling, etc., and the uplink data may be uplink service data, such as video data or audio data.

[0191] It should be noted that the scheduling grant refers to resources allocated to a terminal device by a network device based on a resource request sent by the terminal device. For example, the resource request may be a preamble in a random access process, an uplink scheduling request, etc. The configured grant refers to resources preconfigured by a network device, and the terminal device does not need to send a resource request. The resources are allocated once and used multiple times.

[0192] It should be noted that the terminal device has multiple capabilities, and the capability information can further indicate another capability of the terminal device, which is not limited in this embodiment of the present application.

[0193] Please note that the CU of the network device may further obtain the capability information of the terminal device from the core network device. If the CU of the network device obtains the capability information of the terminal device from the core network device, the CU of the network device does not need to obtain the capability information of the terminal device from the terminal device, that is, in this case, the terminal device does not need to send capability information to the CU of the network device.

[0194] Step 702: The CU of the network device sends a UE context setting request message to the DU of the network device.

[0195] The UE context setting request message may be used to request setting up a context of a terminal device.

[0196] Optionally, the UE context setup request message may include capability information.

[0197] Step 703: The DU of the network device sets a context for the terminal device, and sends a UE context setting response message to the CU of the network device.

[0198] It should be noted that in this embodiment of the present application, the context may include an air interface context and an F1 context.

[0199] The air interface context may refer to the RLC layer configuration, MAC layer configuration, physical layer configuration information, I-RNTI, C-RNTI, etc. of the terminal device, and may further include a "configured grant for data transmission in inactive state", PDCCH configuration information for transmitting physical layer feedback information, and an RNTI for scrambling the PDCCH. The F1 context may refer to the F1 AP ID, transport layer address information for F1 data transmission, etc. The DRB data of the terminal device is transmitted between the CU of the network device and the DU of the network device, and may also be referred to as F1 data transmission.

[0200] In this embodiment of the present application, the context set by the DU of the network device for the terminal device may include one or more of the following:

[0201] 1. Configuration information of a physical downlink control channel (PDCCH) configured for a terminal device. The configuration information of the PDCCH may be used to transmit feedback information of uplink data, or to schedule a PUSCH transmission, and to schedule a physical downlink shared control channel (PDSCH) transmission, etc.

[0202] The configuration information of the PDCCH includes, but is not limited to, resource location information, period, start position, and the like of the PDCCH.

[0203] In this embodiment of the present application, the PDCCH can schedule the transmission of at least one of physical layer signaling, such as Acknowledgement (ACK) or Negative Acknowledgement (NACK) signaling, an uplink grant for initial transmission, and an uplink grant for retransmission. The PDCCH can further schedule the transmission of the PDSCH, and the information carried in the PDSCH includes, but is not limited to, one or more of downlink RRC signaling, downlink data, and a command for timing advance. The terminal device can perform uplink transmission and downlink transmission based on the scheduling of the PDCCH.

[0204] 2. A temporary identifier for scrambling the PDCCH. The temporary identifier is a 32-bit radio network temporary identity (RNTI) for scrambling the PDCCH. For example, the temporary identifier may be a cell radio network temporary identity (C-RNTI) of the terminal device.

[0205] 3. RLC layer configuration information of the radio bearer and configured for the terminal device.

[0206] 4. MAC layer configuration information configured for the end device.

[0207] 5. An inactive radio network temporary identity (I-RNTI) configured for the terminal device.

[0208] 6. A configured grant configured for a terminal device. The configured grant may be used to indicate uplink resources allocated to the terminal device. The configured grant may include, but is not limited to, one or more of a physical uplink shared channel (PUSCH), a frequency domain resource, a period, a starting position, and data demodulation reference information.

[0209] Optionally, the configured grant may be configured for a terminal device in an inactive state, and the terminal device in the inactive state may use the configured grant to transmit one or more of uplink RRC signaling and uplink data.

[0210] Optionally, the time-frequency resource configured by the configured grant may be a dedicated time-frequency resource for the terminal device, i.e., a time-frequency resource that is not shared with another terminal device. In this case, the DU of the network device can establish a mapping relationship between the configured grant and the context of the terminal device, and a mapping relationship between the configured grant and the data transmission channel of the terminal device.

[0211] Optionally, the time-frequency resource configured by the configured grant may be a time-frequency resource shared by the terminal device with another terminal device. In this case, when determining that the terminal device enters an inactive state, the CU of the network device may send an inactive I-RNTI to the DU of the network device. The DU of the network device may establish a mapping relationship between the configured grant and the I-RNTI of the terminal device. The I-RNTI may be a unique identifier of the terminal device in an inactive state in a radio network-based notification area (RAN-based notification area, RNA).

[0212] Please note that the above is just an example, and the context of the terminal device may further include other information. This is not limited in this embodiment of the present application. Details will not be described again using the example of this specification. For example, the UE context setting response message sent by the CU of the network device may include the context of the terminal device.

[0213] In the procedure shown in Fig. 7, only the main steps are described. There may be other steps in the process of setting the context for the terminal device. Details will not be repeated here. The context of the terminal device is set according to the procedure shown in Fig. 7.

[0214] Considering that after leaving the coverage range of the access network device that originally stored the context, the terminal device needs to initiate an RRC resumption procedure to a new access network device. The following describes a specific scenario using an example.

[0215] Scenario 1 As shown in Figure 8, the terminal device moves from cell 1 to neighboring cell 2. In this case, the CU may remain unchanged, and the terminal device is handed over from the DU of the source network device to the DU of the target network device. In this case, the source network device (e.g., the fourth network device) includes the first CU and the second DU, and the target network device (e.g., the first network device) includes the first CU and the first DU.

[0216] In the case of a network device with a CU-DU architecture, the CU of the network device is responsible for managing the RRC state of the terminal device. The CU of the network device stores the context of the terminal device (including the capability information of the terminal device and the configuration information of another terminal device). In a scenario in which the CU of the network device remains unchanged and the DU of the network device is handed over, the CU of the network device can send the context of the terminal device to the DU of the target network device, and the DU of the target network device initiates a random access process of the terminal device for the terminal device based on the received context of the terminal device and allocates a preamble and a C-RNTI to be used by the DU to access the target network device, so that the terminal device can access the CU of the network device via the DU of the target network device. In this way, the random access process of the terminal device is completed.

[0217] In the handover process, the CU of the network device may not include the second information indicating whether the terminal device is a terminal device of reduced capabilities. For example, when the handover occurs, it cannot be determined that the UE is a terminal device of reduced capabilities based on the UE capability information carried in the context of the terminal device. In this case, the DU of the target network device cannot assign the preamble or C-RNTI that matches the terminal device of reduced capabilities to the terminal device of reduced capabilities. In this case, the DU of the target network device cannot properly schedule subsequent messages and cannot perform priority processing for the access of the UE.

[0218] Based on the above problem, an embodiment of the present application provides a communication method. As shown in Figure 9, the communication method includes the following steps:

[0219] Step 901: The first CU initiates an initial handover procedure for handover to the first DU.

[0220] A specific handover manner may be that the first CU initiates a handover request for handover to the first DU.

[0221] For example, the first DU is a target DU and the second DU is a source DU. The handover request may be used to request a terminal device to be handed over to the target DU. After receiving the handover request, the target DU triggers a handover procedure of the terminal device based on the handover request.

[0222] In some embodiments, after receiving the measurement report of the terminal device, the first CU can determine that the terminal device needs to be handed over based on the measurement report. Specifically, if the first CU determines that the current communication quality of the terminal device is low based on the received measurement report, the terminal device may be handed over. In this case, a handover request is sent to the first entity.

[0223] Furthermore, the aforementioned measurement reporting procedure of the terminal device may be actively triggered by the first CU or actively performed by the terminal device. Optionally, the handover request includes one or more of the following information: an identifier of the handover target terminal device, an identifier of the target cell, and target frequency information.

[0224] In a possible embodiment, the first CU can further receive a cell congestion status report sent by the second DU. If the report indicates that the cell is currently in a congested state, the CU of the network device can correspondingly determine a mitigation policy for mitigating the cell congestion status (e.g., releasing low-priority GBR, releasing edge users, etc.), and send a cell congestion mitigation request to the first entity, where the request includes the determined mitigation policy. The first entity can perform the mitigation process according to the mitigation policy. The cell congestion status report includes one or more of the following information: a cell identifier and a bearer type (e.g., GBR or nonGBR), an ARP, a congestion type (e.g., GBR congestion or non-GBR congestion), a congestion level (e.g., severe, mild, not congested), etc.

[0225] Step 902: The first CU sends a first message to the first DU.

[0226] The first message may include second information, the second information indicating a type of the terminal device, the type of the terminal device including: the terminal device is a reduced capability terminal device, or the type of the terminal device is a reduced capability terminal device type.

[0227] In some embodiments, the first message may be a UE context setup request message sent by the first CU to the first DU. The first message may include a first field. The first field may be a newly added field in the UE context request message. The first field is used to indicate or identify UE information, or is used to indicate or identify UE type information. In another example, the first field may be in a CU to DU RRC information field in the UE context request message.

[0228] Table 4 shows fields that may be included in the UE context request message, including, for example, a configured grant confirmation information field (CG-ConfigInfo), a configured grant confirmation field (CG-Config), a terminal device capability RAT list field (UE-capabilityRAT-containerLis), a measurement information field (MeasConfig), a handover preparation information field (handover preparation information), a cell group information field (CellGroupConfig), a measurement timing configuration field (measurement timing configuration), and a first field, for example, a terminal device type field (UE type).

[0229] [Table 4A] [Table 4B]

[0230] For example, referring to Table 4 and Table 2, the first field carried in the first message may be used to indicate the type of the terminal device (UE type), and the value range of the first field may include REDCAP, a type of REDCAP, or another UE type. For example, the identifier of the terminal device may be used to identify the type of the terminal device, where identifier=0 indicates that the terminal device is not configured with a parameter. Identifier=1 indicates that the terminal device is a REDCAP terminal device. Identifier=2 indicates that the terminal device is an NB-IoT terminal device. Identifier=3 to 10 are reserved for future use. Identifier=11 indicates that the terminal device is a terminal device corresponding to access class 11, and so on.

[0231] Step 903: The first DU may schedule a subsequent random access message or another message for the reduced capability terminal device based on the second information.

[0232] It should be noted that step 603 is an optional step. For example, the DU of the network device schedules a message (e.g., message 4 or message 5) in a subsequent random access process within the capability range of the reduced-capability terminal device. Specifically, the first DU can configure corresponding resources for the reduced-capability terminal device. For specific configured resources, please refer to the description of the random access process in Figure 4. Details will not be repeated in this specification.

[0233] Optionally, the first CU may determine, based on the second information, an access priority of the reduced capability terminal device for the reduced capability terminal device.

[0234] For example, the first CU sets the access priority of the terminal device with reduced capabilities to a low priority, and sets the access priority of the terminal device with non-reduced capabilities to a high priority. expensive A priority order can be set so that when a terminal device with reduced capabilities and a terminal device with non-reduced capabilities access the network at the same time, the terminal device with non-reduced capabilities has priority to access the network.

[0235] Scenario 2 As shown in Figure 10, the terminal device moves from cell 1 to cell 3. In this case, the terminal device is handed over from the CU of the source network device to the CU of the target network device, and the terminal device is handed over from the DU of the source network device to the DU of the target network device. In this case, the source network device (e.g., the second network device) includes a second CU and a second DU, and the target network device (e.g., the first network device) includes a first CU and a first DU.

[0236] An embodiment of the present application provides a communication method. As shown in Figure 11, the communication method includes the following steps:

[0237] Step 1101: The second CU initiates a handover procedure to the first CU.

[0238] For example, the CU of the source network device is the second CU, the CU of the target network device is the first CU, the DU of the source network device is the second DU, and the DU of the target network device is the first DU. In this case, the second CU stores the context of the terminal device. In the handover process, the second CU can send the context of the terminal device (which may include, for example, capability information of the terminal device) to the CU of the target network device through a UE context request message. For a specific handover process, please refer to step 901. Details are not repeated in this specification.

[0239] The context request message of the UE may include second information, where the second information indicates information regarding whether the UE is a reduced capability terminal device.

[0240] Step 1102: The first CU initiates a handover procedure to the first DU.

[0241] The CU of the target network device transmits the context of the terminal device (which may include, for example, capability information of the terminal device) to the DU of the target network device, and the DU of the target network device assigns a preamble and a C-RNTI to the terminal device, which are used by the DU to access the target network device, based on the received context of the terminal device. In this way, the random access process of the terminal device is completed. For a specific handover process, please refer to step 901. Details will not be repeated in this specification.

[0242] Step 1103: The first CU sends a first message to the first DU.

[0243] The first message may include second information indicating a type of the terminal device, the type of the terminal device including that the terminal device is a reduced capability terminal device or that the type of the terminal device is a reduced capability terminal device type.

[0244] In some embodiments, the first message may be a UE context setup request message sent by the first CU to the first DU. The first message may include a first field. The first field may be a newly added field in the UE context request message. The first field is used to indicate or identify UE information, or is used to indicate or identify UE type information. In another example, the first field may be in a CU to DU RRC information field in the UE context request message.

[0245] Step 1104: The first DU may schedule a subsequent random access message or another message for the reduced capability terminal device based on the second information.

[0246] It should be noted that step 603 is an optional step. For example, the first DU schedules a message (e.g., message 4 or message 5) in a subsequent random access process within the capability range of the reduced capability terminal device. Specifically, the first DU can configure corresponding resources for the reduced capability terminal device. For specific configured resources, please refer to the description of the random access process in Figure 4. Details will not be repeated in this specification.

[0247] Optionally, the first CU may determine, based on the second information, an access priority of the reduced capability terminal device for the reduced capability terminal device.

[0248] For example, the first CU sets the access priority of the terminal device with reduced capabilities to a low priority, and sets the access priority of the terminal device with non-reduced capabilities to a high priority. expensive A priority order can be set so that when a terminal device with reduced capabilities and a terminal device with non-reduced capabilities access the network at the same time, the terminal device with non-reduced capabilities has priority to access the network.

[0249] It should be noted that not all of the above steps 1101 to 1104 need to be performed. In some embodiments, some of steps 1101 to 1104 may be performed, for example, steps 1101, 1103, and 1104 are performed, or steps 1102, 1103, and 1104 are performed. This is not limited herein.

[0250] Scenario 3 When the RRC state of the terminal device changes, the CU of the network device needs to notify the DU of the network device to perform related context processing. Specifically, in the process of the terminal device changing from the RRC connected state to the inactive state, the CU of the network device notifies the DU of the network device to release the context of the terminal device. The context includes all dedicated F1 transmission resources, configuration information of the air interface, etc. If the DU of the network device releases the context of the terminal device, when the terminal device in the inactive state sends uplink data to the DU of the network device, the DU of the network device cannot immediately send data to the CU of the network device.

[0251] When the terminal device moves in an inactive state, for example, when moving from cell 1 to cell 3, in this case, the terminal device needs to resume the RRC state resume request. In the process of completing the handover from the DU of the source network device to the DU of the target network device, or in the process of the handover from the CU of the source network device to the CU of the target network device and from the DU of the source network device to the DU of the target network device, if the UE cannot be directly identified as a REDCAP UE based on the UE capability information, the DU of the network device does not know that the UE is a REDCAP UE when allocating the preamble or C-RNTI, and the DU of the network device cannot know that the UE is a REDCAP UE based on the preamble of message 1 or the C-RNTI of message 3. As a result, the subsequent messages cannot be scheduled properly, or the priority processing cannot be performed for the access of the UE. In the following, an example will be described in which the source network device (e.g., the second network device) includes a second CU and a second DU, and the target network device (e.g., the first network device) includes a first CU and a first DU. For a scheme in which a source network device (e.g., a third network device) includes a first CU and a second DU, and a target network device (e.g., a first network device) includes a first CU and a first DU, please refer to this embodiment.

[0252] Based on the aforementioned problem, an embodiment of the present application provides a communication method. As shown in Figure 12, the communication method includes the following steps:

[0253] Step 1201: A terminal device initiates an RRC connection resumption procedure to a second CU via a second DU.

[0254] For example, the second DU may be a DU of a source network device, and the second CU may be a CU of the source network device. The first DU may be a DU of a target network device, and the first CU may be a CU of the target network device. In this case, the terminal device initiates an RRC connection resume request to the CU of the source network device via the DU of the source network device. The RRC connection resume request is used to request the resumption of the RRC connection state.

[0255] Step 1202: The second CU initiates a handover procedure to the first CU.

[0256] In this case, the CU of the source network device determines that the terminal device needs to be handed over based on the RRC connection resumption request of the terminal device and the stored context of the terminal device. Thus, the CU of the source network device can send the context of the terminal device (which may include, for example, capability information of the terminal device) to the CU of the target network device via a UE context request message.

[0257] The context request message of the UE may include second information, where the second information indicates information regarding whether the UE is a reduced capability terminal device.

[0258] Step 1203: The first CU initiates a handover procedure to the first DU.

[0259] The CU of the target network device sends the context of the terminal device (which may include, for example, capability information of the terminal device) to the DU of the target network device, and the DU of the target network device assigns a preamble and a C-RNTI to the terminal device, which are used by the DU to access the target network device, based on the received context of the terminal device. In this way, the random access process of the terminal device is completed.

[0260] Step 1204: The first CU sends a first message to the first DU.

[0261] The first message may include second information indicating a type of the terminal device, the type of the terminal device including that the terminal device is a reduced capability terminal device or that the type of the terminal device is a reduced capability terminal device type.

[0262] In some embodiments, the first message may be a UE context setup request message sent by the first CU to the first DU. The first message may include a first field. The first field may be a newly added field in the UE context request message. The first field is used to indicate or identify UE information, or is used to indicate or identify UE type information. In another example, the first field may be in a CU to DU RRC information field in the UE context request message.

[0263] Step 1205: The first DU may schedule a subsequent random access message or another message for the reduced capability terminal device based on the second information.

[0264] It should be noted that step 1205 is an optional step. For example, the DU schedules a message (e.g., message 4 or message 5) in a subsequent random access process within the capability range of the reduced-capability terminal device. Specifically, the DU can configure corresponding resources for the reduced-capability terminal device. For specific configured resources, please refer to the description of the random access process in Figure 4. Details are not repeated in this specification.

[0265] Optionally, the CU may determine an access priority of the reduced capability terminal device for the reduced capability terminal device based on the second information. For example, the CU may set the access priority of the reduced capability terminal device to a low priority and set the access priority of the non-reduced capability terminal device to a low priority. expensive A priority order can be set so that, when a terminal device with reduced capabilities and a terminal device with non-reduced capabilities access the network at the same time, the terminal device with non-reduced capabilities is given priority to access the network.

[0266] It should be noted that not all of the above steps 1201 to 1205 need to be performed. In some embodiments, some of steps 1201 to 1205 may be performed, for example, steps 1202, 1204, and 1205 are performed, or steps 1203, 1204, and 1205 are performed. This is not limited herein.

[0267] Based on the above problem, an embodiment of the present application provides a communication method. A terminal device first accesses a network through a second distributed unit and a first central unit (e.g., a fourth network device), subsequently accesses the network through a first distributed unit and a first central unit (e.g., a first network device), and then accesses the network through a third distributed unit and a first central unit (e.g., a fifth network device). As shown in Figure 13, the method includes the following steps:

[0268] Step 1301a: The terminal device sends first information to the second distributed unit.

[0269] In step 1301a, the terminal device may access the network through the second distributed unit and the first central unit. In this case, the manner in which the terminal device transmits the first information to the first distributed unit in FIG. 5 may be referred to.

[0270] Step 1302a: The second distributed unit sends a second message to the first central unit. Ji Send.

[0271] Second Message To For this, please refer to the manner in which the terminal device sends the second message to the first distributed unit in FIG.

[0272] Step 1301b: The terminal device sends first information to the first central unit.

[0273] In step 1301b, the terminal device may access the network through the second distributed unit and the first central unit. In this case, the manner in which the terminal device transmits the first information to the central unit through the distributed unit in FIG. 6 may be referred to.

[0274] It should be noted that steps 1301a and 1302a are possible implementations, and step 1301b is a possible implementation.

[0275] Step 1303: The first distributed unit and the first central unit initiate an initial handover procedure of the terminal device.

[0276] Optionally, the terminal device may initiate an initial handover from the second distributed unit to the first distributed unit to access the first distributed unit. For details, refer to the implementation of handover to the first distributed unit in step 901 of FIG. 9.

[0277] Step 1304: The first central unit sends a first message a to the first distributed unit.

[0278] For the manner in which the first central unit sends the first message a to the first distributed unit in step 1304, please refer to the manner in which the first central unit sends the first message to the first distributed unit in step 902. The first message a may be the same as the first message.

[0279] Step 1305: The first distribution unit schedules resources of the terminal device based on the second information.

[0280] It should be noted that step 1305 is an optional step.

[0281] Step 1306: The third distributed unit and the first central unit initiate an initial handover procedure of the terminal device.

[0282] Optionally, the terminal device may initiate an initial handover from the first distributed unit to the third distributed unit to access the third distributed unit. For details, refer to the implementation of handover to the first distributed unit in step 901 of FIG. 9 .

[0283] Step 1307: The first central unit sends a first message b to the third distributed unit.

[0284] For the manner in which the first central unit sends the first message b to the third distributed unit in step 1304, please refer to the manner in which the first central unit sends the first message to the first distributed unit in step 902. The first message b may be the same as the first message.

[0285] Step 1308: The third distributed unit schedules resources of the terminal device according to the second information.

[0286] It should be noted that step 1308 is an optional step.

[0287] The above method is described only using an example in which the first central unit is not changed. The method in which the handover is also performed in the first central unit can be described with reference to the embodiment of FIG. 13 and FIG. 12. For example, the terminal device first accesses the second central unit through the second distributed unit, and then the terminal device is handed over to the first central unit and the first distributed unit. Then, the terminal device can be further handed over from the first central unit to the third central unit, and from the first distributed unit to the third distributed unit, that is, the terminal device accesses the third network device (including the third central unit and the third distributed unit).

[0288] Of course, other combination methods may be used instead. For a specific manner of transmitting the first information and the second information in handover, please refer to the above-mentioned embodiment. Details are not repeated in this specification.

[0289] Please note that all of the above steps 1301a to 1308 need not be performed. This is not limited in this specification. Note that Figures 9 to 13 are examples. In the actual process, there may be other steps, and the details will not be described again in this specification.

[0290] The embodiments described in this specification may be independent solutions or may be combined based on internal logic, all of which are within the protection scope of this application.

[0291] In the above embodiments provided in the present application, the methods provided in the embodiments of the present application are described separately in terms of interactions between devices. To implement the functions in the methods provided in the embodiments of the present application, the CU of the network device or the DU of the network device may include a hardware structure and / or a software module, and may implement the above functions in the form of a hardware structure, a software module, or a combination of a hardware structure and a software module. Whether a function among the above functions is performed by a hardware structure, a software module, or a combination of a hardware structure and a software module depends on the specific application and design constraints of the technical solution.

[0292] In the embodiment of the present application, the module division is an example, and is merely a logical functional division, and there may be other division methods in actual implementation. In addition, the functional modules in the embodiment of the present application may be integrated into one processor, or may exist physically alone, or two or more modules may be integrated into one module. The integrated module may be implemented in the form of hardware, or may be implemented in the form of a software functional module.

[0293] As shown in FIG. 14, the present application provides a communication device.

[0294] In some embodiments, the communication apparatus 1400 may be used in a first central unit of a network device, in which case the first central unit may include a processing module 1410 and may optionally further include a transmitting module 1420 and a receiving module 1430.

[0295] The processing module 1410 is configured to receive first information from the terminal device via the receiving module 1430, where the first information indicates a type of the terminal device. The processing module 1410 is configured to transmit second information to a first distributed unit of the network device via the transmitting module 1420, where the second information indicates a type of the terminal device. 2 The information indicates the type of terminal device.

[0296] In a possible embodiment, the processing module 1410 is configured to receive first information from a terminal device via a first distributed unit via the receiving module 1430 .

[0297] In a possible embodiment, the processing module 1410 is configured to receive first information from the terminal device via the receiving module 1430 via a second distributed unit, the second distributed unit being a distributed unit accessed by the terminal device before the terminal device is handed over to the first distributed unit.

[0298] In a possible embodiment, the processing module 1410 is configured to receive, via the receiving module 1430, first information transmitted by a second central unit, the second central unit being a central unit accessed by the terminal device before the terminal device is handed over to the first central unit.

[0299] In a possible embodiment, the first distribution unit schedules resources of the terminal devices and / or access priorities of the terminal devices based on the second information.

[0300] In a possible embodiment, the processing module 1410 is configured to transmit the second information via the transmitting module 1420 to a third distributed unit, the third distributed unit being a distributed unit to which the terminal device is handed over from the first distributed unit.

[0301] In a possible embodiment, the processing module 1410 is configured to transmit the first information to a third central unit via the transmitting module 1420, the third central unit being a central unit to which the terminal device is handed over from the first central unit, and the first information is to be used by the third central unit to transmit the second information to a third distributed unit, the third distributed unit being a distributed unit to which the terminal device is handed over from the first distributed unit.

[0302] In a possible implementation, the second information is carried in a first message, the first message includes a first field, and the first field carries the second information.

[0303] In some embodiments, the communication apparatus 1400 may be used in a first distributed unit of a network device, where the first distributed unit may include a processing module 1410 and may optionally further include a transmitting module 1420 and a receiving module 1430.

[0304] The processing module 1410 is configured to receive first information from the terminal device via the receiving module, the first information indicating a type of the terminal device. The processing module 1410 is configured to transmit second information to a first central unit of the network device via the transmitting module 1420, the second information indicating a type of the terminal device.

[0305] In possible implementations, the type of terminal device includes any one of the following: a reduced capability terminal device or a type of reduced capability terminal device.

[0306] In a possible embodiment, the first central unit controls the access of the terminal device based on the second information.

[0307] In a possible embodiment, the first central unit transmits the second information to a third distributed unit, which is the distributed unit to which the terminal device is handed over from the first distributed unit.

[0308] In a possible embodiment, the first central unit transmits the second information to a third central unit, which is a central unit to which the terminal device is handed over from the first central unit.

[0309] In a possible embodiment, the second information is used to control the access of the terminal device.

[0310] In a possible implementation, the second information is carried in a second message, the second message including the first field, the first field carrying the second information.

[0311] In a possible embodiment, the first message is either a downlink radio resource control message transfer message or a terminal device context request message, and the second message is an initial uplink radio resource control message transfer message.

[0312] In a possible embodiment, the first information is carried by message 1 or message 3.

[0313] In possible implementations, the first distributed unit and the first central unit are separate network elements in a first network device, the first network device being configured for a terminal device to access the network, the second distributed unit and the second central unit are separate network elements in a second network device, the second network device being configured for a terminal device to access the network, the third distributed unit and the third central unit are separate network elements in a third network device, the third network device being configured for a terminal device to access the network, the second distributed unit and the first central unit are separate network elements in a fourth network device, the fourth network device being configured for a terminal device to access the network, or the third distributed unit and the first central unit are separate network elements in a fifth network device, the fifth network device being configured for a terminal device to access the network.

[0314] Optionally, the aforementioned communication device 1400 may further include a storage unit. The storage unit is configured to store data or instructions (which may also be referred to as code or program). The aforementioned units may interact with or be connected to the storage unit to perform corresponding methods or functions. For example, the processing module 1410 may read data or instructions in the storage unit so that the communication device performs the method of the aforementioned embodiment.

[0315] It should be understood that the division of units in the device is merely a logical division of functions. In actual implementation, the front or part of the units may be integrated into one physical entity or may be physically separated. In addition, all units in the device may be implemented in the form of software called by a processing element, or may be implemented in the form of hardware. Alternatively, some units may be implemented in the form of software calls by a processing element, and some units may be implemented in the form of hardware. For example, each unit may be a processing element located separately, or may be integrated into a chip of the device for implementation. In addition, each unit may alternatively be stored in a memory in the form of a program, and the function of the unit is called and executed by a processing element of the device. In addition, all or part of these units may be integrated or implemented independently. Alternatively, the processing element described herein may be a processor or an integrated circuit having signal processing capabilities. In the implementation process, the steps of the above-mentioned method or the above-mentioned units may be implemented using integrated logic circuits of hardware in the processing element, or by calling software by the processing element.

[0316] In one example, a unit in any one of the aforementioned devices may be one or more integrated circuits configured to implement the aforementioned method, such as one or more application specific integrated circuits (ASICs), one or more microprocessors (digital signal processors (DSPs), one or more field programmable gate arrays (FPGAs), or a combination of at least two of these integrated circuit forms. As another example, if a unit in an apparatus can be implemented in a form of scheduling a program by a processing element, the processing element may be a general-purpose processor such as a central processing unit (CPU) or another processor that can call a program. As another example, such a unit may be integrated and implemented in a form of a system-on-a-chip (SOC).

[0317] The aforementioned unit for receiving (e.g., receiving unit) is an interface circuit of the device and is configured to receive a signal from another device. For example, if the device is implemented in a chip format, the receiving unit is an interface circuit used by the chip to receive a signal from another chip or device. The aforementioned unit for transmitting (e.g., transmitting unit) is an interface circuit of the device and is configured to transmit a signal to another device. For example, if the device is implemented in a chip format, the transmitting unit is an interface circuit used by the chip to transmit a signal to another chip or device.

[0318] FIG. 15 is a schematic diagram of the structure of a communication device according to an embodiment of the present application. The communication device is configured to implement the operation of the first central unit of the network device or the first distributed unit of the network device in the above-mentioned embodiment. As shown in FIG. 15, an example in which the communication device is the first central unit of the network device or the first distributed unit is used as an example. The communication device includes an antenna 1510, a radio frequency unit 1520, and a signal processing unit 1530. The antenna 1510 is connected to the radio frequency unit 1520. In the downlink direction, the radio frequency unit 1520 receives information transmitted by the network device or another terminal device via the antenna 1510, and transmits the information transmitted by the network device or another terminal device to the signal processing unit 1530 for processing. In the uplink direction, the signal processing unit 1530 processes information from the terminal device and transmits the information to the radio frequency unit 1520. The radio frequency unit 1520 processes information from the terminal device and then transmits the information to the network device or another terminal device via the antenna 1510.

[0319] An example is used in which the communication device is a network device, and the communication device includes an antenna 1510, a radio frequency unit 1520, and a signal processing unit 1530. The antenna 1510 is connected to the radio frequency unit 1520. In the uplink direction, the radio frequency unit 1520 receives information transmitted by the first terminal or another terminal device via the antenna 1510, and transmits the information transmitted by the first terminal or another terminal device to the signal processing unit 1530 for processing. In the downlink direction, the signal processing unit 1530 processes information from the network device and transmits the information to the radio frequency unit 1520. The radio frequency unit 1520 processes information from the network device and then transmits information to the first terminal or another terminal device via the antenna 1510.

[0320] The signal processing unit 1530 is configured to process each communication protocol layer of data. The signal processing unit 1530 may be a subsystem of a communication device, which may further include another subsystem, for example a central processing subsystem configured to perform processing on the operating system and application layers of the communication device. In another example, a peripheral subsystem is configured to perform a connection to another device. The signal processing unit 1530 may be a separately located chip. Optionally, the aforementioned devices may be located in the signal processing unit 1530.

[0321] The signal processing unit 1530 may include one or more processing elements 1531, for example including a main control CPU or other integrated circuits, and may include an interface circuit 1533. The signal processing unit 1530 may further include a memory element 1532. The memory element 1532 is configured to store data and programs. A program for executing the method executed by the communication device in the above-mentioned manner may or may not be stored in the memory element 1532, for example, may be stored in a memory external to the signal processing unit 1530. The signal processing unit 1530 loads the program into a cache when in use. The interface circuit 1533 is configured to communicate with the device. The aforementioned device may be disposed in the signal processing unit 1530. The signal processing unit 1530 may be realized using a chip. The chip includes at least one processing element and an interface circuit. The processing element is configured to execute steps of any method executed by the aforementioned communication device. The interface circuit is configured to communicate with other devices. In one embodiment, the unit for performing the steps of the aforementioned method may be implemented in the form of scheduling a program by a processing element. For example, the apparatus includes a processing element and a storage element, and the processing element calls a program stored in the storage element to perform the method performed by the communication device in the aforementioned method embodiment. The storage element may be a storage element located on the same chip as the processing element, i.e., an on-chip storage element.

[0322] In another embodiment, the program used to execute the method performed by the communication device in the above-mentioned method may be a storage element located on a different chip than the processing element, i.e. an off-chip storage element, in which case the processing element calls the program from the off-chip storage element or loads the program into the on-chip storage element in order to call and execute the method performed by the communication device (the first central unit or the first distributed unit of the network device) in the above-mentioned method embodiments.

[0323] In yet another embodiment, the units used by the communication device to perform the steps of the above method may be configured as one or more processing elements. These processing elements are located in the signal processing unit 1530. The processing elements herein may be integrated circuits, such as one or more ASICs, one or more DSPs, one or more FPGAs, or a combination of these integrated circuits. These integrated circuits may be integrated to form a chip.

[0324] The units for performing the steps of the aforementioned method may be integrated and implemented in the form of a system-on-a-chip (SOC), and the SOC chip is configured to perform the aforementioned method. At least one processing element and a storage element may be integrated in the chip, and the processing element calls a program stored in the storage element to perform the aforementioned method performed by the communication device. Alternatively, at least one integrated circuit may be integrated in the chip and configured to perform the aforementioned method performed by the communication device. Alternatively, referring to the aforementioned embodiments, the functions of some units may be implemented in the form of calling a program by the processing element, and the functions of some units are implemented in the form of an integrated circuit.

[0325] It can be seen that the aforementioned apparatus may include at least one processing element and an interface circuit, and the at least one processing element is configured to perform any method performed by the communication device provided in the aforementioned method embodiments. The processing element may perform some or all of the steps performed by the communication device in a first manner by calling a program stored in a storage element. Alternatively, the processing element may perform some or all of the steps performed by the communication device in a second manner by using an integrated logic circuit in hardware in the processing element in combination with an instruction. Indeed, some or all of the steps performed by the communication device may be alternatively performed with reference to the first method and the second manner.

[0326] The processing element herein is the same as that described above and may be a general purpose processor, such as a CPU, or one or more integrated circuits configured to implement the above-described method, such as one or more ASICs, one or more microprocessors DSPs, one or more FPGAs, or a combination of at least two of these integrated circuit forms. The storage element may be a memory or may be a collective term for multiple storage elements.

[0327] It is understood that the memory in this embodiment of the present application may be a volatile memory or a non-volatile memory, or may include a volatile memory and a non-volatile memory. The non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM) and is used as an external cache. By way of example and not limitation, many forms of RAM may be used, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchlink dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that memory in the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0328] An embodiment of the present application further provides a computer-readable storage medium storing a computer program, which, when executed by a computer, performs a method corresponding to any one of the above method embodiments applied to a first central unit or a first distributed unit of a network device.

[0329] An embodiment of the present application further provides a computer program product, which, when executed by a computer, performs the method described in any method embodiment applied to the first central unit or the first distributed unit of the network device.

[0330] It should be noted that terms such as "first" and "second", e.g., "first instruction information and second instruction information", are used merely to distinguish between descriptions and are not intended to indicate or imply relative importance or order. "At least one" means one or more, and "multiple" means two or more. The term "and / or" describes an association relationship to describe associated objects and indicates that three relationships may exist. For example, A and / or B may represent the following three cases: only A is present, both A and B are present, and only B is present, where A and B may be singular or plural. The character " / " generally indicates an "or" relationship between associated objects. "At least one of the following items" or similar expressions refer to any combination of these items, including any combination of singular items or multiple items. For example, at least one of a, b, or c can represent a, b, c, a and b, a and c, b and c, or a, b, and c, where a, b, and c may be singular or plural.

[0331] All or part of the above-mentioned embodiments may be implemented by software, hardware, firmware, or any combination thereof. When software is used to implement the embodiments, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer programs. When the computer programs are loaded and executed on a computer, all or part of the procedures or functions according to the embodiments of the present application are generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer program may be stored in a computer-readable storage medium or transmitted from a computer-readable storage medium to another computer-readable storage medium. For example, the computer program may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center in a wired (e.g., coaxial cable, optical fiber, or digital subscriber line (DSL)) manner or a wireless (e.g., infrared, radio, or microwave) manner. The computer-readable storage medium may be any available medium accessible by a computer, or a data storage device, such as a server or a data center, incorporating one or more available media. The usable media may be magnetic media (e.g., a floppy disk, hard disk, or magnetic tape), optical media (e.g., a high density digital video disc (DVD)), semiconductor media (e.g., a solid state disk (SSD)), and the like.

[0332] An embodiment of the present application further provides a processing device, including a processor and an interface, the processor being configured to execute a method as described in any one of the preceding method embodiments applied to a first central unit or a first distributed unit of a network device.

[0333] It should be understood that the processing device may be a chip and the processor may be implemented in hardware or in software. If implemented in hardware, the processor may be a logic circuit, an integrated circuit, etc. If implemented in software, the processor may be a general-purpose processor and is implemented by reading software code stored in a memory. The memory may be integrated into the processor or may exist independently and be located outside the processor.

[0334] The above description is only a specific embodiment of the present application, and is not intended to limit the protection scope of the embodiments of the present application. Any variation or replacement that can be easily understood by a person skilled in the art within the technical scope disclosed in the embodiments of the present application shall be included in the protection scope of the embodiments of the present application. Therefore, the protection scope of the embodiments of the present application shall be subject to the protection scope of the claims. [Explanation of symbols]

[0335] 101 Terminal Device 102 Network Devices 1400 Communication Equipment 1410 Processing Module 1420 Transmitting Module 1430 Receiver Module 1510 Antenna 1520 Radio Frequency Device 1530 Signal Processing Unit 1531 Processing element 1532 Memory element 1533 Interface Circuit

Claims

1. 1. A communication method comprising: receiving, by a first distribution unit of a network device, first information from a terminal device, the first information indicating that the terminal device is a type of a reduced capability terminal device, and the first distribution unit using an initial bandwidth portion corresponding to a message 1 as the first information; sending, by the first distributed unit, second information to a first central unit of the network device, the second information indicating the type of the terminal device; A communication method comprising:

2. The method of claim 1 , wherein the first central unit controls access of the terminal device based on the second information. initiating, by the first central unit, a handover procedure of the terminal device to a second distributed unit of the network device, the handover procedure not including the conveyance of the second information; transmitting, by the first central unit, the second information to the second distributed unit; 3. The method of claim 1 or 2, further comprising:

4. A method for providing a method for a mobile terminal device, comprising: initiating, by the first central unit, a handover procedure of the terminal device to a second central unit of a second network device different from the network device; initiating, by the second central unit, a handover procedure of the terminal device to a second distributed unit of the second network device, the handover procedure not including the second information; transmitting, by the second central unit, the second information to the second distributed unit; 3. The method of claim 1 or 2, further comprising:

5. The method according to claim 3 or 4, wherein the second information is used to control access of the terminal device.

6. 6. The method of claim 1, wherein the second information is carried in a second message, the second message including a first field, the first field carrying the second information.

7. the second message is an initial uplink radio resource control message transfer message; The method of claim 6.

8. the first distributed unit and the first central unit are separate network elements in a first network device, the first network device being configured to allow the terminal device to access a network; or The second distributed unit and the second central unit are separate network elements in a second network device, and the second network device is configured to allow the terminal device to access a network; or The third distributed unit and the third central unit are separate network elements in a third network device, and the third network device is configured to allow the terminal device to access a network; or the second distributed unit and the first central unit are separate network elements in a fourth network device, the fourth network device being configured for the terminal device to access a network; or the third distributed unit and the first central unit are separate network elements in a fifth network device, the fifth network device being configured to allow the terminal device to access a network; 8. The method according to any one of claims 1 to 7.

9. A set of communication devices including one or more communication devices, each communication device including a processor and a communication interface, the communication interface configured to allow each communication device to communicate, the processor coupled to a memory, the memory configured to store a program or instructions, and when the program or instructions are executed by the processor, the one or more communication devices are enabled to perform a method according to any one of claims 1 to 8.

10. The set of communications devices of claim 9, wherein each communications device is a network device.

11. 9. A computer readable storage medium having instructions stored thereon that, when executed on a computer, enable the computer to perform the method of any one of claims 1 to 8.

12. A chip comprising one or more processors and a communication interface, the one or more processors configured to read instructions for performing the method of any one of claims 1 to 8.

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