Communication method, and apparatus

Abstract

A communication method and an apparatus, which are used for reducing the transmission overhead of a MAC PDU. The method comprises: a terminal device acquires a first MAC PDU, the first MAC PDU comprising a first MAC header and a first SDU, the first MAC header not carrying a first field, and the first field being used for indicating the length of the first SDU; and the terminal device sends the first MAC PDU.

Description

Communication method and apparatus

[0001] Cross-reference to Related Applications

[0002] This application claims priority to the Chinese Patent Application No. 202410798152.4, filed on June 19, 2024, and entitled "A Communication Method and Apparatus", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the field of mobile communication technology, and in particular to a communication method and apparatus. BACKGROUND

[0004] In wireless communication technology, the transmission content between a terminal and an access network device can be divided into control signaling and user plane data, wherein the control signaling is transmitted in the control plane, and the user plane data is transmitted in the user plane. Taking the transmission process of data as an example, the data is encapsulated in each layer, for example, the service data unit (SDU) of the media access control (MAC) layer received from the upper layer is encapsulated into a MAC protocol data unit (PDU) after layer encapsulation, and then is transmitted to the next layer.

[0005] At present, how to reduce the transmission overhead of the MAC PDU is a technical problem to be solved. SUMMARY

[0006] The present application provides a communication method and apparatus to reduce the transmission overhead of the MAC PDU.

[0007] In a first aspect, a communication method is provided. The method can be implemented by a first communication apparatus. The first communication apparatus can be a terminal device (such as a user equipment (UE), an internet of things (IoT) terminal, an ambient IoT (AIoT) terminal, etc.), or a component in the terminal device, for example, a terminal apparatus. The component in the present application may, for example, include at least one of a chip, a chip system, a processor, a transceiver, a processing unit, or a transceiving unit. Taking the terminal device as an example, the method can be implemented by the following steps: the terminal device obtains a first MAC PDU, the first MAC PDU including a first MAC header and a first SDU, wherein the first MAC header does not carry a first field, and the first field is used to indicate the length of the first SDU; and the terminal device transmits the first MAC PDU.

[0008] Based on the implementation mode, the field for indicating the length of the first SDU is not carried in the MAC header of the first MAC PDU, and the transmission overhead of the MAC PDU can be reduced.

[0009] The first SDU can be a first MAC SDU. The first field can be an L field.

[0010] In a possible implementation mode, the terminal device is an Internet of Things terminal device, for example, the terminal device is an AIoT terminal or an IoT terminal, etc. Therefore, the method can reduce the transmission overhead of the Internet of Things terminal device, so as to reduce the power consumption of the Internet of Things terminal device.

[0011] In a possible implementation mode, the first MAC PDU includes one SDU (i.e., the first SDU), or in other words, the terminal device transmits the first MAC PDU in a single bearer transmission mode, or in other words, the terminal device adopts a single bearer transmission mode. Based on the implementation mode, the first aspect and each possible implementation mode can be applied to a scenario in which the first MAC PDU includes only one SDU, or in other words, the first aspect and each possible implementation mode can be applied to a scenario in which the terminal device transmits the first MAC PDU in a single bearer transmission mode, or in other words, the first aspect and each possible implementation mode can be applied to a scenario in which the terminal device adopts a single bearer transmission mode.

[0012] In a possible implementation mode, the first MAC PDU includes a second field, and the second field is used to indicate whether the first MAC PDU carries the first field. Based on the implementation mode, the terminal device can indicate whether the first MAC PDU carries the first field through the second field, and correspondingly, the network device can determine whether the first MAC PDU carries the first field according to the second field. If the network device determines that the first field is carried according to the second field, the length of the first SDU can be determined according to the first field. In addition, if the network device determines that there is no first field according to the second field, it can be determined that all bits other than the first MAC header are bits occupied by the first SDU, and correspondingly, the first SDU can be parsed to obtain the data carried by the first SDU.

[0013] In a possible implementation, the terminal device can further receive first resource configuration information, used to configure a transmission resource of the first MAC PDU, and a size of the transmission resource is equal to a size of a resource occupied by the first MAC PDU. Based on the implementation, the network device configures, for the terminal device, a transmission resource of the first MAC PDU equal to a size of a resource occupied by the first MAC PDU. In other words, in a case where the network device configures a size of a transmission resource of the first MAC PDU equal to a size of a resource occupied by the first MAC PDU, the first MAC PDU without the first field can be transmitted. The size of the resource occupied by the first MAC PDU can be understood as a size of a resource occupied by data (or a data packet) to be transmitted by the terminal device, which can be considered as the same as the size of the resource occupied by the first MAC PDU.

[0014] In a possible implementation, the terminal device can further transmit a second MAC protocol data unit, which includes a second MAC header, a second service data unit, and padding bits, where the second MAC header carries a third field used to indicate a length of the second service data unit. Based on the implementation, the terminal device can transmit the first MAC PDU and the second MAC PDU, where the first MAC PDU and the second MAC PDU can be used to carry data of a same radio bearer (such as a same SRB or DRB). Optionally, a size of a transmission resource of the first MAC PDU (such as a resource size indicated by the first resource configuration information) is smaller than a size of a resource occupied by the data in the radio bearer. In this case, the third field used to indicate the length of the second SDU can be included in the second MAC PDU, for example, the third field can be an L field.

[0015] In a possible implementation, the third field is used to indicate length information of the second service data unit and / or length information of the padding bits. In the implementation, the third field can indicate the length of the second SDU and / or the length of the padding bits, to improve indication flexibility. For example, the third field can indicate a smaller one of the length of the second SDU and the length of the padding bits, to further reduce transmission overhead.

[0016] In a possible implementation, the terminal device further receives first information used to determine sending the first MAC information. In this implementation, the network device can instruct the terminal device to adopt the first aspect and possible implementation manners thereof, i.e., instruct the terminal device to send the first MAC PDU described above, by the first information. The first information can be determined by the network device (such as a base station, a central unit (CU), a distributed unit (DU), or a radio unit (RU)) according to the device type or the transmission type of the terminal device.

[0017] In a second aspect, a communication method is provided. The method can be implemented by a second communication apparatus. In this application, the second communication apparatus can be an access network apparatus. The access network apparatus can be an access network device or a component in the access network device. In this application, the component can include at least one of a chip, a chip system, a processor, a transceiver, a processing unit, or a transceiving unit, for example. The access network device can be a base station, a CU, a DU, an RU, or the like. The access network apparatus can also be referred to as a network apparatus or a network device. Taking the network device as an execution subject for example, the method can be implemented by the following steps: the network device receives a MAC PDU, the first MAC PDU including a first MAC header and a first SDU, wherein the first MAC header does not carry a first field used to indicate the length of the first SDU; and the network device further obtains data carried by the first SDU.

[0018] Based on this implementation, the network device can regard all bits other than the first MAC header as bits occupied by the first SDU when the first MAC PDU does not contain the first field, and accordingly can parse the first SDU to obtain the data carried by the first SDU.

[0019] In a possible implementation, the terminal device is an Internet of Things terminal device.

[0020] In a possible implementation, the first MAC PDU includes one service data unit.

[0021] In a possible implementation, the terminal device sends the first MAC PDU in a single-carry transmission manner.

[0022] In a possible implementation, the first MAC PDU includes a second field used to indicate whether the first MAC PDU carries the first field.

[0023] In a possible implementation, the network device can further send first resource configuration information for configuring a transmission resource of the first MAC protocol data unit, and a size of the transmission resource is equal to a size of a resource occupied by the first MAC protocol data unit.

[0024] In a possible implementation, the network device can further receive a second MAC protocol data unit, where the second MAC protocol data unit includes a second MAC header, a second service data unit, and padding bits, and the second MAC header carries a third field for indicating a length of the second service data unit.

[0025] In a possible implementation, the third field is used for indicating length information of the second service data unit and / or length information of the padding bits.

[0026] In a possible implementation, the network device can further send first information for determining that the Internet of Things device sends the first MAC information.

[0027] In a possible implementation, the network device is a DU, and the network device can further receive second information from a central unit, where the second information is used for indicating a device type or a transmission type of the terminal device, and the network device can determine to send the first information according to the device type or the transmission type of the terminal device.

[0028] The beneficial effects of the above second aspect and each possible implementation thereof can refer to the description of the beneficial effects of the first aspect and the corresponding implementation, which will not be repeated here.

[0029] In a third aspect, a communication apparatus is provided. The apparatus can implement the method in any of the above first aspect to the second aspect and any possible implementation thereof. The apparatus has the functions of the above first communication apparatus or the second communication apparatus. The apparatus is, for example, a terminal device, or a functional module in a terminal device, or a network device or a functional module in a network device, etc.

[0030] In an alternative implementation, the apparatus can include a module corresponding to each of the methods / operations / steps / actions of any possible implementation of any of the first aspect to the second aspect, which can be implemented in hardware circuit, software, or combination of hardware circuit and software. In an alternative implementation, the apparatus includes a processing unit (sometimes referred to as a processing module) and a communication unit (sometimes referred to as a transceiver module, a communication module, etc.). The transceiver unit can implement the transmitting function and the receiving function. When the transceiver unit implements the transmitting function, it can be referred to as a transmitting unit (sometimes referred to as a transmitting module). When the transceiver unit implements the receiving function, it can be referred to as a receiving unit (sometimes referred to as a receiving module). The transmitting unit and the receiving unit can be the same functional module, which is referred to as a transceiver unit, and can implement the transmitting function and the receiving function. Alternatively, the transmitting unit and the receiving unit can be different functional modules, and the transceiver unit refers to these functional modules in general.

[0031] For example, when the apparatus is configured to perform the method described in any of the first aspect to the second aspect, the apparatus can include a communication unit and a processing unit.

[0032] In the fourth aspect, the embodiments of the present application further provide a communication apparatus, including a processor configured to execute a computer program (or computer executable instructions) stored in a memory, when the computer program (or computer executable instructions) is executed, causing the apparatus to perform the method described in any possible implementation of any of the first aspect to the second aspect.

[0033] In a possible implementation, the processor and the memory are integrated together.

[0034] In another possible implementation, the memory is located outside the communication apparatus.

[0035] The communication apparatus further includes a communication interface configured to enable the communication apparatus to communicate with other devices, such as transmitting or receiving data and / or signals. For example, the communication interface can be a transceiver, a circuit, a bus, a module, or other types of communication interfaces.

[0036] In the fifth aspect, a computer readable storage medium is provided, which is configured to store a computer program or instructions, when the computer program or instructions are executed, causing the method described in any possible implementation of any of the first aspect to the second aspect and the method described in any possible implementation of any of the first aspect to the second aspect to be implemented.

[0037] In the sixth aspect, a computer program product including instructions is provided, when the computer program product is executed on a computer, causing the method described in any possible implementation of any of the first aspect to the second aspect to be implemented.

[0038] In a seventh aspect, an embodiment of the present application further provides a communication apparatus, configured to execute the method in any possible implementation of the method of the first aspect to the second aspect.

[0039] In an eighth aspect, a chip system is provided, which includes a circuit (or can be understood as including a processor, which can include a circuit, etc.), and can further include an input / output interface. The input / output interface can be used for inputting a message, and can also be used for outputting a message. The input / output interface can be the same interface, i.e., the same interface can realize both the sending function and the receiving function; or the input / output interface includes an input interface and an output interface, the input interface is used to realize the receiving function, i.e., is used to receive a message; and the output interface is used to realize the sending function, i.e., is used to send a message. The circuit can include a logic circuit and / or an analog circuit. The circuit can be used to perform operations other than the transceiving function in the method of any possible implementation of any one of the first aspect to the second aspect; and the circuit can also be used to transmit a message to the input / output interface, or receive a message from the input / output interface from another communication apparatus. The chip system can be used to realize the method of any possible implementation of any one of the first aspect to the second aspect. The chip system can be composed of a chip, or can include a chip and other discrete devices.

[0040] Optionally, the chip system can further include a memory or a circuit, the memory can be used to store instructions, and the memory or the circuit can invoke the instructions stored in the memory to realize corresponding functions.

[0041] In a ninth aspect, a communication method is provided, which can include the method implemented by the first communication apparatus in the first aspect and any possible implementation thereof, and the method implemented by the second communication apparatus in the second aspect and any possible implementation thereof.

[0042] In a tenth aspect, a communication system is provided, which can include a first communication apparatus and a second communication apparatus. The first communication apparatus can be used to realize the method in the first aspect and any possible implementation thereof, and the second communication apparatus can be used to realize the method in the second aspect and any possible implementation thereof.

[0043] The technical effects brought by the above third aspect to the tenth aspect can be referred to the description of the beneficial effects of the corresponding solutions in the first aspect to the second aspect, which will not be described herein. BRIEF DESCRIPTION OF DRAWINGS

[0044] FIG. 1 is a schematic diagram of an architecture of a wireless communication system;

[0045] FIG. 2 is a schematic diagram of protocol layers between a terminal device and an access network device;

[0046] FIG. 3 is a schematic diagram of a MAC PDU structure;

[0047] FIG. 4 is a schematic diagram of a header structure in a MAC PDU;

[0048] FIG. 5 is a schematic diagram of a structure of an open access network system;

[0049] FIG. 6 is a schematic diagram of a structure of an open access network device;

[0050] FIG. 7 is a schematic diagram of a flow of a communication method provided by an embodiment of the present application;

[0051] FIG. 8 is a schematic diagram of a header structure in a first MAC PDU provided by an embodiment of the present application;

[0052] FIG. 9 is a schematic diagram of a sending flow of first information under a CU-DU structure provided by an embodiment of the present application;

[0053] FIG. 10 is a schematic diagram of a header structure in another first MAC PDU provided by an embodiment of the present application;

[0054] FIG. 11 is a schematic diagram of a MAC PDU structure provided by an embodiment of the present application;

[0055] FIG. 12 is a schematic diagram of a structure of a communication apparatus provided by an embodiment of the present application;

[0056] FIG. 13 is a schematic diagram of a structure of another communication apparatus provided by an embodiment of the present application. DETAILED DESCRIPTION

[0057] Embodiments of the present application provide a communication method and apparatus. The method and apparatus are based on the same inventive concept, and the implementation of the apparatus and the method can be referred to each other since the principles of the method and the apparatus for solving problems are similar, and the repeated parts will not be described herein.

[0058] Figure 1 is a schematic diagram of an architecture of a communication system to which embodiments of the present application are applied. As shown in Figure 1, the communication system includes an access network 100 and a core network 200, and optionally, the communication system can also include an Internet 300. The radio access network (RAN) 100 can include at least one RAN device (e.g., 110a and 110b in Figure 1) and at least one terminal (e.g., 120a-120j in Figure 1). The terminal is connected to the RAN device by wireless means, and the RAN device is connected to the core network by wireless or wired means. The core network device and the RAN device can be independent and different physical devices, or can be integrated into the same physical device with the functions of the core network device and the logical functions of the RAN device, or can be a physical device integrated with part of the functions of the core network device and part of the functions of the RAN device. The terminals and the terminals, and the RAN devices and the RAN devices can be connected to each other by wired or wireless means. Figure 1 is only a schematic diagram, and it can be understood that in addition to the RAN device, the communication system can also include other network devices, such as wireless relay devices and wireless backhaul devices, etc., which are not shown in Figure 1.

[0059] In this application, the network device is a network side device with transceiving function. For example, the network device can be an apparatus in a RAN that provides priority and / or wireless communication function for a terminal device, referred to as a RAN device. The RAN can be an access network in the 3rd generation partnership project (3GPP), for example, a 4th generation (4G), a 5th generation (5G), or a future communication network. The RAN can also be an open RAN (O-RAN or ORAN), a cloud radio access network (CRAN), or a communication network of two or more of the above networks. The RAN device can be a base station in a long term evolution (LTE) or LTE advanced (LTE-A) communication system, an evolved NodeB (eNodeB), a transmission reception point (TRP), a next generation NodeB (gNB) in a 5th generation (5G) mobile communication system, a base station in a future mobile communication system, an access node in a wireless fidelity (WiFi) system, a long range radio (LoRa) system, or a vehicle-to-everything system. The RAN device can also be a module or unit that completes part of the function of the base station, for example, can be a CU, can be a DU, and can also be a RU. For example, the CU is configured to implement the functions of the packet data convergence protocol (PDCP) layer and above protocol layers (such as the RRC layer and / or the service data adaptation protocol (SDAP) layer, etc.); the DU is configured to implement the functions of the protocol layer below the PDCP layer (such as the radio link control (RLC) layer, the MAC layer, and / or the physical (PHY) layer, etc.). For specific descriptions of the above protocol layers, please refer to the relevant technical specifications of the 3rd generation partnership project (3GPP). The CU and the DU can be separately arranged, or can also be included in the same network element, such as a baseband unit (BBU).The RU can be included in a radio frequency device or a radio frequency unit, for example, included in a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH). In different systems, the CU, the DU, or the RU can also have different names, but those skilled in the art can understand their meanings. For example, in an ORAN system, the CU can also be referred to as an O-CU (open CU), the DU can also be referred to as an O-DU, and the RU can also be referred to as an O-RU. Any of the CU (or CU-control plane (CP), CU-user plane (UP)), the DU, and the RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module. The wireless access network device can be a macro base station (such as 110a in FIG. 1), or a micro base station or indoor station (such as 110b in FIG. 1), or a relay node or donor node, etc. The embodiments of this application do not limit the specific technology and specific device form adopted by the wireless access network device. For ease of description, the network device can be referred to as a wireless access network device, and the base station can be an example of the wireless access network device.

[0060] It can be understood that the communication between the access network device and the terminal device follows a certain protocol layer structure. For example, the control plane protocol layer structure can include an RRC layer, a PDCP layer, an RLC layer, a MAC layer, and a PHY layer; and the user plane protocol layer structure can include a PDCP layer, an RLC layer, a MAC layer, and a PHY layer. In a possible implementation, the PDCP layer can further include an SDAP layer. The SDAP layer, the PDCP layer, the RLC layer, the MAC layer, and the PHY layer can also be collectively referred to as an access layer. For specific descriptions of the above-mentioned protocol layers, reference can be made to the relevant technical specifications of the Third Generation Partnership Project 3GPP.

[0061] Taking data transmission between the access network device and the terminal device as an example, the data transmission needs to pass through the user plane protocol layer, such as the SDAP layer, the PDCP layer, the RLC layer, the MAC layer, and the PHY layer. For example, please refer to FIG. 2, which is a schematic diagram of downlink data transmission between layers. The so-called downlink data is data sent by the access network device to the terminal device. In FIG. 2, the downward arrow represents data transmission, and the upward arrow represents data reception.

[0062] After the SDAP layer entity obtains data from the upper layer, the data is mapped to a corresponding PDCP layer entity, the PDCP layer entity delivers the data to at least one RLC layer entity corresponding to the PDCP layer entity, and then the at least one RLC layer entity delivers the data to a corresponding MAC layer entity, and then the MAC layer entity generates a transport block (TB), and then the corresponding PHY layer entity performs wireless transmission. The data is encapsulated in each layer. The data received by a layer from the upper layer of the layer is the SDU of the layer, and after layer encapsulation, it becomes a PDU, and is then delivered to the next layer. For example, the data received by the PDCP layer entity from the upper layer (such as the application layer) is called the PDCP SDU, and the data sent by the PDCP layer entity to the lower layer (such as the RLC layer) is called the PDCP PDU in the PDCP layer; the data (such as the PDCP PDU) received by the RLC layer entity from the upper layer (such as the PDCP layer) is called the RLC SDU in the RLC layer, and the data sent by the RLC layer entity to the lower layer (such as the MAC layer) is called the RLC PDU; the data (such as the RLC PDU) received by the MAC layer entity from the upper layer (such as the RLC layer) is called the MAC SDU, and the data sent by the MAC layer entity to the lower layer (such as the PHY layer) is called the MAC PDU.

[0063] It can be understood that data can be transmitted between different protocol layers through corresponding channels. For example, data can be transmitted between the RLC layer entity and the MAC layer entity through a logical channel (LCH), and data can be transmitted between the MAC layer entity and the physical layer entity through a transport channel.

[0064] At present, the format of the MAC PDU defined by 5G NR includes, for example, the example in FIG. 3. As can be seen, the MAC PDU includes a header or multiple sub-headers. In addition, the MAC PDU can also include at least one of a MAC control element (MAC CE), a MAC SDU, and padding bits (or padding information or padding). The MAC CE, the MAC SDU, and the padding bits can also be referred to as MAC payload. Any sub-header can correspond to one MAC CE, one MAC SDU, or padding bits.

[0065] The structure of the header (or sub-header) will be introduced below in conjunction with FIG. 4. The header (or sub-header) can include at least one of the following terminals of the terminal:

[0066] 1, the R field, indicating a reserved bit.

[0067] 2, F field, indicating the length of the length field L. Wherein, if the value of the F field is 0, it indicates that the header (or subheader) contains an 8-bit length L; if the value of the F field is 1, it indicates that the header (or subheader) contains a 16-bit length L.

[0068] 3, L field, i.e. length field, indicating the length of the MAC SDU.

[0069] 4, logical channel identifier (LCID), used to indicate the logical channel between the RLC layer entity and the MAC layer entity. The LCID length is, for example, 5 bits (bit).

[0070] 5, extend logical channel identifier (eLCID), used to indicate the logical channel between the RLC layer entity and the MAC layer entity.

[0071] It can be understood that the numbers (a), (b) and (c) in FIG. 4 respectively represent a plurality of possible structures of the header (or subheader), i.e. any header (or subheader) can adopt any structure in FIG. 4.

[0072] It can be understood that, similar to the access network device, the access layer of the terminal device also has an SDAP layer, a PDCP layer, an RLC layer, a MAC layer and a physical layer. The terminal device also has an application layer and a non-access layer. Among them, the application layer can be used to provide services to the application program installed in the terminal device, for example, the downlink data received by the terminal device can be transmitted to the application layer by the physical layer in turn, and then provided to the application program by the application layer. For another example, the application layer can obtain the data generated by the application program (such as the video recorded by the user using the application program, etc.), and transmit the data to the physical layer in turn to send to other communication devices. The non-access layer can be used to forward user data, such as forwarding the uplink data received from the application layer to the SDAP layer or forwarding the downlink data received from the SDAP layer to the application layer.

[0073] FIG. 5 is an example diagram illustrating an O-RAN system, which can include other components than those shown in FIG. 5.

[0074] As shown, an access network device (e.g., can be an eNB or gNB or next generation base station, etc.) communicates with a core network device through a backhaul link. The access network device can also communicate with a UE through an air interface. A specific communication process can include that a BBU in the access network device communicates with the core network through the backhaul link, and an RU in the access network device communicates with at least one UE through the air interface. Wherein the BBU can communicate with at least one RU through a fronthaul link. The BBU and the RU can be co-located or not co-located. The BBU includes at least one CU and at least one DU, which can communicate through at least one midhaul link.

[0075] FIG. 6 is a diagram illustrating a network element function division and protocol layer structure of an access network device under an O-RAN architecture. In some examples, the CU of the access network device is a logical node carrying the radio resource control (RRC) layer, the service data adaptation protocol (SDAP) layer, the packet data convergence protocol (PDCP) layer and other control functions of the access network device. The CU is connected to network nodes such as core network through some interfaces, which can be E2 interface or the like. Optionally, the CU can have part of the functions of the core network. The CU (e.g., PDCP layer and higher layer) is connected to the DU (e.g., radio link control (RLC) layer and lower layer) through some interfaces, which can be F1 interface or the like. In some examples, these interfaces (e.g., F1 interface) can provide control plane (C-Plane) and user plane (U-Plane) functions (e.g., interface management, system information management, UE context management, RRC message transmission, etc.). F1AP is the application protocol of F1 interface, which defines the signaling process of F1 in some examples. The F1 interface supports control plane F1-C and user plane F1-U.

[0076] In some examples, a CU can be split into a CU-CP and a CU-UP, where the CU-CP is a logical node carrying the RRC layer and the PDCP control plane part of PDCP (PDCP-C) layer, for implementing the control plane function of the CU. The CU-CP can interact with a network element in the core network for implementing the control plane function. The network element in the core network for implementing the control plane function can be an access and mobility function network element, such as an access and mobility management function (AMF) network element in a 5G system. The CU-UP is a logical node carrying the SDAP layer and the PDCP-U (user plane part of PDCP) layer, for implementing the user plane function of the CU. The CU-UP can interact with a network element in the core network for implementing the user plane function. The network element in the core network for implementing the user plane function, such as a user plane function (UPF) in a 5G system, is responsible for forwarding and receiving data in the terminal device. The above configurations of the CU and the DU are merely examples, and the CU and the DU can be configured to have other functions according to needs. For example, the CU or the DU can be configured to have more protocol layer functions, or the CU or the DU can be configured to have partial processing functions of the protocol layers. For example, partial functions of the RLC layer and functions of the protocol layers above the RLC layer are arranged in the CU, and the remaining functions of the RLC layer and functions of the protocol layers below the RLC layer are arranged in the DU. For another example, the functions of the CU or the DU can be divided according to service types or other system requirements, for example, functions that need to meet a relatively low latency requirement in processing time are arranged in the DU, and functions that do not need to meet the latency requirement are arranged in the CU.

[0077] In some examples, a DU can carry a logical node of the RLC layer, the MAC layer, the higher physical layer (higher PHY), or other functions. In some examples, the DU can control at least one RU. The DU is connected to the RU through some interfaces, which can be front-haul interfaces.

[0078] In some examples, a CU can have no PDCP layer, for example, only including the RRC layer. The CU-CP can have no PDCP-C. The CU-UP can have no PDCP-U, or there is no CU-UP at all. In some examples, a DU can have no RLC layer, for example, only having the MAC and the higher physical layer. In addition, in some examples, an O-RAN device can also have no CU and only include the DU, i.e., no RRC layer.

[0079] In some examples, the higher physical layer includes portions of PHY layer processing such as forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, and other processing functions. In some examples, the RU is a logical node that hosts a lower physical layer (lower PHY) and radio frequency (RF) processing. In some examples, the RU can be a 3GPP TRP or RRH or other similar functional entity. In some examples, the lower physical layer includes portions of PHY processing such as fast Fourier transform (FFT), inverse fast Fourier transformation (IFFT), digital beamforming and filtering, and other processing functions. The RU communicates with one or more UEs over a wireless link.

[0080] In some examples, the DU and the RU can or can not be co-located. The DU and the RU exchange control plane information and user plane information over a fronthaul link via a lower-layer split-control, user and synchronization (LLS-CUS) interface. The LLS-CUS can include LLS-C interface and LLS-U interface that provide C-Plane and LLS-C interface and LLS-U interface that provide U-Plane, respectively. In some examples, the C-Plane refers to real-time control between the DU and the RU. The DU and the RU exchange management information such as management plane (M-Plane) (or M-Plane) over a LLS-M interface of the fronthaul link. The M-Plane refers to non-real-time management operations between the DU and the RU. The DU and the RU can cooperate to collectively implement the functionality of the PHY layer. One DU can be connected to one or more RUs. The functionality of the DU and the RU can be configured in multiple ways depending on the design. For example, the DU is configured to implement baseband functionality and the RU is configured to implement mid- RF functionality. As another example, the DU is configured to implement higher layer functionality in the PHY layer and the RU is configured to implement lower layer functionality in the PHY layer or to implement the lower layer functionality and RF functionality. The higher layer functionality in the PHY layer can include a portion of the functionality of the PHY layer that is closer to the MAC layer, and the lower layer functionality in the PHY layer can include another portion of the functionality of the PHY layer that is closer to the mid-RF side.

[0081] It can be understood that the access network device can be a device including one or more of the CU, the DU, or the AAU. In addition, the CU can be divided into a network device in the access network, or the CU can be divided into a network device in the core network (CN), which is not limited in the present application.

[0082] The terminal is a device with wireless transceiving function, which can send signals to the base station or receive signals from the base station. The terminal can also be referred to as a terminal device, a UE, a mobile station, a mobile terminal, etc. The terminal can be widely applied to various scenarios, such as device-to-device (D2D), vehicle to everything (V2X) communication, machine-type communication (MTC), internet of things (IoT), virtual reality, augmented reality, industrial control, automatic driving, remote medical treatment, smart power grid, smart furniture, smart office, smart wear, smart traffic, smart city, smart home, etc. The terminal can be a mobile phone, a tablet computer, a computer with wireless transceiving function, a wearable device, a vehicle, an airplane, a ship, a robot, a mechanical arm, a smart home device, etc. The embodiments of the present application do not limit the specific technology and specific device form of the terminal.

[0083] It can be understood that the terminal in the present application can be a device with backscatter function, for example, an AIoT terminal. The AIoT terminal can also be referred to as a tag or an AIoT tag or a terminal in the AIoT scenario or a tag in the AIoT scenario. The AIoT terminal can be a terminal device supporting radio frequency identification (RFID) technology.

[0084] The types of AIoT terminals can be classified based on whether the communication mode is based on backscatter. For example, AIoT terminals can be divided into three types: active terminals, passive terminals, and semi-active terminals, and the types of tags can be divided into active tags, passive tags, and semi-passive tags. Among them, passive tags and semi-passive tags adopt a communication mode based on reflection; active tags adopt a technology of actively generating a carrier, i.e., non-reflection-based communication. The AIoT terminal can also be referred to as an AIoT device, i.e., in order to distinguish from the 5G terminal, it can also be referred to as a device.

[0085] In addition, the AIoT terminal can also be classified based on the ability of having energy storage and the ability of not having energy storage, or based on the ability of combining both. For example, the AIoT terminal in the present application can also be referred to as an AIoT device. The AIoT device can be device A, device B, or device C. Among them, device A refers to a device without energy storage and without independent signal generation, for example, it can be a device with the specific feature of backscatter transmission. Device B can be a device with energy storage but without independent signal generation, for example, it can be a device with the specific feature of backscatter transmission, and the use of stored energy can include amplification of reflected signals. Device C can be a device with energy storage and with independent signal generation, for example, an active wireless radio frequency component for transmission.

[0086] In the embodiments of the present application, the functions of the base station can also be performed by a module (such as a chip) in the base station, or by a control subsystem containing the functions of the base station. The control subsystem containing the functions of the base station herein can be a control center in the above-mentioned application scenarios such as smart grid, industrial control, intelligent transportation, and smart city. The functions of the terminal can also be performed by a module (such as a chip or modem) in the terminal, or by a device containing the functions of the terminal.

[0087] In the present application, the base station sends downlink (DL) signals or downlink information to the terminal, and the downlink information is carried on the downlink channel; the terminal sends uplink (UL) signals or uplink information to the base station, and the uplink information is carried on the uplink channel.

[0088] It can be understood that the roles of the base station and the terminal in the present application can be relative, for example, the helicopter or the unmanned aerial vehicle 120i in FIG. 1 can be configured as a mobile base station, and for those terminals 120j that access the wireless access network 100 through 120i, the terminal 120i is a base station; but for the base station 110a, 120i is a terminal, that is, 110a and 120i communicate through a wireless air interface protocol. Of course, 110a and 120i can also communicate through an interface protocol between base stations and base stations, at this time, relative to 110a, 120i is also a base station. Therefore, the base station and the terminal can be collectively referred to as a communication device, 110a and 110b in FIG. 1 can be referred to as a communication device with base station functions, and 120a-120j in FIG. 1 can be referred to as a communication device with terminal functions.

[0089] In this application, the base station is taken as an example of the access network device in the subsequent description. The base station and the terminal can be in a fixed position or mobile. The base station and the terminal can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; can also be deployed on the water surface; can also be deployed on an airplane, a balloon and a man-made satellite. The embodiments of the present application do not limit the application scenarios of the base station and the terminal.

[0090] In this application, the network device can also include a CN device. The core network element can include a mobility management network element, mainly used for mobility management and access management, etc. In the 5G communication system, the access management network element can be AMF, mainly performing functions such as mobility management, access authentication or authorization, etc.

[0091] In the future communication system, for example, in the future communication system, the mobility management network element can still use its name in the 5G communication system, or can also have other names, and the embodiments of the present application do not limit this. The functions of the above-mentioned network elements or devices can be completed by one independent network element, or can be completed by several network elements together. In actual deployment, the network elements in the core network can be deployed on the same or different physical devices.

[0092] It can be understood that the mobility management network element can be a network element in a hardware device, or a software function running on a dedicated hardware, or a virtualized function instantiated on a platform (for example, a cloud platform). Optionally, the above-mentioned network element or function can be realized by one device, or can be realized by multiple devices together, or can be a functional module in a device, and the embodiments of the present application do not make specific limitations.

[0093] In this application, the AMF is taken as an example of the mobility management network element or the core network element in the subsequent description.

[0094] With the increasingly wide application of 5G NR communication MTC technology and IoT communication, the number of IoT devices is growing day by day. Therefore, the industry is increasingly demanding the reduction of the cost and power consumption of IoT devices. In the 4G period, 3GPP introduced a narrowband internet of things (NB-IoT) system to reduce the cost and power consumption of IoT devices. But the NB-IoT terminal still needs overall external power supply, such as through a battery or external power supply function, and the NB-IoT terminal has the ability to generate a local high-frequency local oscillator carrier, so such a terminal can only have a milliwatt-level power consumption, which needs to be further reduced. RFID technology gives a good technical reference in the direction of low power consumption, which can support micro-watt-level power consumption, so it has better application prospects. In this application, the AIoT terminal can use a low-precision low-power mid-low-frequency ring oscillator or a completely local-oscillator-free receiving downlink signal. For example, when the AIoT terminal is working, the energy and carrier of the communication come from the reader supply, and the communication is based on the reflected carrier. The reader can be a handheld or fixed device that reads AIoT terminal information. Alternatively, the reader can also be used to write information to the AIoT terminal. In this application, the form of the reader is not limited, which can be a base station, a terminal, a relay node, or an integrated access and backhaul (IAB) node. For example, when the reader is a terminal, the communication between the reader and the AIoT terminal can be regarded as the transmission between terminals. For another example, when the reader is a base station, the communication between the reader and the AIoT terminal is a universal user to network interface (Uu) interface, that is, the reader and the AIoT terminal perform air interface communication. The AIoT terminal can be located within the coverage range provided by the reader.

[0095] At present, the transmission overhead of the MAC PDU is large. As shown in FIG. 4, the structure of the MAC PDU header or subheader currently used is shown, and it can be seen that any MAC PDU header (or subheader) needs at least 2 octets in length. In particular, for IoT terminals or AIoT terminals, the current transmission overhead of the MAC PDU leads to excessive power consumption of the terminal device. Therefore, how to reduce the transmission overhead of the MAC layer has become a technical problem to be solved.

[0096] In view of this, the scheme of the embodiments of the present application is proposed. In the embodiments of the present application, the header or subheader of the MAC PDU sent by the terminal device to the access network device can not carry an indication field (such as the L field shown in FIG. 4) for indicating the data length of the MAC SDU, so the transmission overhead of the MAC PDU can be reduced. The reduction of the transmission overhead of the MAC PDU can reduce the power consumption of the terminal device.

[0097] The scheme provided by the embodiments of the present application will be described below with reference to the drawings.

[0098] In the following introduction process, the communication method provided by the embodiments of the present application is applied to the network architecture shown in FIG. 1 to FIG. 4 as an example, and the communication method provided by the embodiments of the present application can be executed by a first communication device and a second communication device. The steps executed by the first communication device can be implemented by a terminal device (specifically, for example, an IoT terminal or an AIoT terminal), a component (such as a chip, or other processing unit or processor, transceiver unit or transceiver, etc.) in the terminal device, or a device or equipment that completes part of the functions of the terminal device. The steps executed by the second communication device can be implemented by the access network device (such as a base station) itself, a component (such as a baseband chip, or other processing unit or processor, etc.) in the access network device, or a device or equipment that includes part of the functions of the access network device, for example, the access network device can be a CU, DU or RU that completes part of the functions of the second access network device. The specific forms of the first communication device and the second communication device are not limited, for example, the first communication device can be a chip, and the second communication device can be a device (such as a base station); or the first communication device and the second access network device are both chips or both devices.

[0099] In the following, the communication method provided by the present application is introduced in FIG. 7, taking the first communication device as a terminal device and the second communication device as a base station as an example. It can be understood that the terminal device in the following can be replaced by an AIoT terminal, an IoT terminal, a terminal, a first communication device, a first communication device, etc. In addition, the base station in the following can be replaced by a network device, a second communication device, a RAN device. As shown in FIG. 5, the communication method provided by the embodiments of the present application can include the following steps:

[0100] S101: The terminal device acquires a first MAC PDU.

[0101] S101 can be understood as that the MAC layer entity of the terminal device generates the first MAC PDU. The first MAC PDU can include a MAC header and a MAC SDU.

[0102] For convenience of distinction, the MAC header carried in the first MAC PDU can be referred to as the first MAC header, and the MAC SDU carried in the first MAC PDU can be referred to as the first MAC SDU.

[0103] It can be understood that the first MAC header can be a header or a subheader, which is not specifically limited. If the first MAC PDU includes only one MAC SDU (i.e., the first MAC SDU) and does not carry a MAC CE and padding bits, the first MAC header is a header. If the first MAC PDU includes the first MAC SDU and additionally includes a MAC CE or padding bits, the first MAC header can be a subheader. A plurality of subheaders can be collectively referred to as a header.

[0104] In this application, the first MAC PDU does not carry a field for indicating the length of the first MAC SDU. For the convenience of description, the field can be referred to as a first field hereinafter. The first field can be an L field. For example, the L field can refer to the description of FIG. 4.

[0105] Taking FIG. 8 as an example, (a) shows an exemplary implementation of the first MAC header, in which the first MAC header can be composed of an R field, an F field, an E field, and an LCID. (b) shows another exemplary implementation of the first MAC header, in which the first MAC header can be composed of an R field, an F field, and an LCID. (c) shows another exemplary implementation of the first MAC header, in which the first MAC header can be composed of an R field, an F field, an LCID, and an eLCID. The F field, the LCID, and the eLCID can refer to the description of FIG. 4.

[0106] Optionally, the first MAC PDU can carry a second field, which can be used to indicate whether the first field is carried in the first MAC header. For example, the second field takes a first value (such as 1), indicating that the first field is carried in the first MAC header, and takes a second value (such as 0), indicating that the first field is not carried in the first MAC header.

[0107] As an example, the second field is carried in the first MAC header. The second field occupies fewer bits than the L field originally occupies. For example, the second field shares bits with the F field in the first MAC header; for example, the F field in the first MAC header shown in (a), (b), or (c) of FIG. 8 can be used to indicate whether the first field is carried in the first MAC header. For another example, the second field can occupy one or more bits originally belonging to the L field.

[0108] In a possible embodiment, the terminal device in the present application adopts a single-bearer transmission mode, for example, the terminal device only supports the single-bearer transmission mode, or the terminal device is configured to adopt the single-bearer transmission mode. Or it can be said that the first MAC PDU contains only one MAC SDU, or it can be said that the first MAC PDU transmits the first MAC SDU in the single-bearer transmission mode. Wherein, the single-bearer transmission mode refers to transmitting data of only one radio barrier in one MAC PDU, and the radio barrier here includes a data radio barrier (DRB) and a signaling radio bearer (SRB) (such as SRB1). That is, the first MAC PDU is used to carry data of only one DRB, and for the data of the same DRB, it is usually only necessary to carry it through one MAC SDU. For another example, the first MAC PDU is used to carry data of only one SRB, and for the data of the same SRB, it is usually only necessary to carry it through one MAC SDU.

[0109] That is, the method in the present application can be adopted in the case that the terminal device adopts the single-bearer transmission mode, the first MAC PDU contains only one MAC SDU, and / or the first MAC PDU transmits the first MAC SDU in the single-bearer transmission mode, that is, in the case that the AIoT terminal adopts the single-bearer transmission mode, the first MAC PDU contains only one MAC SDU, and / or the first MAC PDU transmits the first MAC SDU in the single-bearer transmission mode, the scheme in FIG. 7 is executed, that is, in the above case, the first field is not carried in the first MAC header of the first MAC PDU, or in other words, at this time, the first field is not carried in the first MAC header.

[0110] In a possible embodiment, the terminal device can determine to perform the method in the present application according to the transmission resource of the first MAC PDU configured by the base station. For example, the terminal device can receive first resource configuration information from the base station, the first resource configuration information can be used to configure the transmission resource of the first MAC PDU (or the configured transmission resource), for example, the first resource configuration information can indicate the transmission resource allocated by the base station for the terminal device. The terminal device can compare the size of the configured transmission resource with the size of the transmission resource occupied by the first data packet to be transmitted, and determine whether the first field is carried in the first MAC PDU according to the comparison result. Wherein, the size of the transmission resource occupied by the first data packet to be transmitted can be understood as the same as the size of the transmission resource allocated for it, wherein the first data packet to be transmitted can be understood as at least one RLC PDU, and the at least one RLC PDU corresponds to the first MAC SDU. For example, the terminal device can determine to transmit at least one RLC PDU (which can contain segmented SDU) according to the size of the transmission resource configured by the base station, at this time it can be determined that the at least one RLC PDU transmitted corresponds to the first MAC SDU, for example, when it is determined to transmit one RLC PDU, the first MAC PDU can be generated according to the RLC PDU, and for example, when it is determined to transmit multiple RLC PDUs, the first MAC SDU can be generated according to the first (or non-last) RLC PDU. For another example, the size of the transmission resource occupied by the first data packet can be understood as the sum of the resource size of the at least one RLC PDU and the resource size occupied by the first MAC header. Therefore, it can also be considered that comparing the size of the configured transmission resource with the size of the transmission resource occupied by the first data packet to be transmitted means comparing the size of the configured transmission resource with the size of the transmission resource occupied by the first MAC PDU. For example, in the case where the size of the configured transmission resource is equal to the size of the transmission resource occupied by the first MAC PDU, the first data packet to be transmitted does not need to be split into multiple MAC SDUs for transmission, and it is not necessary to increase the padding bits to perform the method in FIG. 7, that is, to generate the first MAC PDU without carrying the first field.

[0111] For example, it is assumed that the first MAC header is composed of an R field, an F field, an E field and an LCID, and the specific field name is not limited, and the first data packet to be transmitted is the data to be sent by the terminal device, which is understood as a MAC SDU. Before generating the first MAC PDU, the terminal device can determine the resource size occupied by the first MAC header according to the format of the MAC header, and determine the resource size occupied by the first MAC SDU according to the size of the RLC PDU. The first MAC PDU can be composed of the first MAC header and the first MAC SDU, and the size of the time-frequency resource occupied by the first data packet (or the size of the transmission resource occupied by the first MAC PDU) is equal to the sum of the resource size occupied by the first MAC header and the resource size occupied by the first MAC SDU. The terminal device can then compare the size of the transmission resource configured by the base station with the size of the time-frequency resource occupied by the first data packet (or the size of the transmission resource occupied by the first MAC PDU), and if they are equal, the first MAC header can be generated, and the first MAC PDU can be further generated according to the first MAC header and the first MAC SDU. In addition, if the size of the transmission resource allocated by the base station is not equal to the size of the time-frequency resource occupied by the first data packet, for example, if the size of the transmission resource allocated by the base station is greater than the size of the time-frequency resource occupied by the first data packet, padding bits need to be carried in the first MAC PDU, and at this time, the first MAC header can carry the first field for indicating the length of the MAC SDU, or the first MAC header can carry the field for indicating the length of the padding bits. For another example, if the size of the transmission resource allocated by the base station is less than the size of the time-frequency resource occupied by the first data packet, the first data packet needs to be split into multiple RLC PDUs for transmission, which will be introduced below in combination with the embodiments of the terminal device sending the first MAC PDU and the second MAC PDU, which will not be expanded here.

[0112] Optionally, the terminal device can report the buffered data size or the data size to be transmitted to the base station through a buffer status report (BSR). For example, the BSR can indicate the data size of the RLC PDU buffered in the first RLC layer. Accordingly, the base station can learn the data size range to be transmitted by the terminal device according to the BSR, and allocate transmission resources accordingly. For example, the base station can send the terminal device the first resource configuration information according to the BSR. Considering that there can be multiple data packets (or buffered data) to be transmitted from multiple radio bearers at this time, such as the first data packet to be transmitted and other data packets, the BSR can be triggered according to different bearers or logical channels at this time. For example, the BSR can carry logical channel information for indicating the logical channel of the data. When there are multiple logical channels with data, multiple BSRs can be carried in a MAC PDU and sent, where the multiple BSRs can be carried in one MAC CE in the MAC PDU or in multiple MAC CEs in the MAC PDU, which is not specifically limited. Correspondingly, the resource scheduled by the base station can indicate the resource allocated for the data packet to be transmitted of which logical channel, that is, the logical channel information is included in the resource scheduling information of the base station.

[0113] In a possible embodiment, the terminal device can receive first information from the base station before S101. The first information can be used by the terminal device to determine whether to send the first MAC PDU described above, that is, to determine whether to send the MAC PDU that does not contain the L field. Therefore, the terminal device can determine whether to perform the flowchart of FIG. 7 according to the first information, or in other words, the terminal device can determine whether to perform S101 and the subsequent steps according to the first information. For example, the first information can be switch information, which is used to indicate whether to send the first MAC PDU described above or to indicate whether to send according to the single bearer mode. For example, when the first information takes a first value (such as 1), it is used by the terminal device to determine to send the first MAC PDU, and when the first information takes a second value (such as 0), it is used by the terminal device to determine not to send the first MAC PDU described above.

[0114] Specifically, the first information can be an indication for a MAC packet transmission (including transmission of at least one RLC PDU) process. For example, the first information can be an indication of single bearer transmission when the first information takes a first value, and can be an indication of closing or stopping single bearer transmission when the first information takes a second value, i.e., the first information can be used to indicate whether the terminal device adopts a single bearer transmission mode, wherein if the single bearer transmission mode is adopted, the terminal device can determine to perform the scheme of FIG. 7. Optionally, the indication of single bearer transmission can be applicable to a certain bearer at least one RLC PDU sending process, and the scheme of FIG. 7 can be performed until the terminal device receives an indication of closing or stopping single bearer transmission. After receiving a resource scheduling, the MAC layer interacts with the RLC layer and determines how many RLC PDUs can be transmitted.

[0115] For another example, the first information taking a first value can represent or indicate that the terminal device sends a simplified or improved MAC header, and the first information taking a second value can represent or indicate that the terminal device closes or stops sending the simplified or improved MAC header, i.e., the first information can be an indication of whether to send a simplified or improved MAC header. The simplified or improved MAC header does not include a field for indicating the length of a MAC SDU. The first information can also be applicable to a certain bearer at least one RLC PDU sending process, and the terminal device can perform the scheme of FIG. 7 until the terminal device receives an indication of closing or stopping sending the simplified or improved MAC header.

[0116] Alternatively, the first information can be an indication for a MAC packet transmission process. For example, the first information can be used to represent or indicate that the first MAC PDU contains only one MAC SDU, or in other words, the first information can be used to represent or indicate that the first MAC PDU adopts a single bearer transmission mode to send the first MAC SDU. Optionally, the indication can be understood as being effective only for the first MAC PDU, e.g., the terminal device adopts the scheme of FIG. 7 in the next RLC PDU sending process after receiving the indication, and the subsequent sending process can not adopt the method.

[0117] Specifically, the first information can come from a base station. The base station can send the first information according to terminal type information of the terminal device. For example, when the terminal type indicates that the terminal device communicating with the base station is an AIoT terminal or an IoT terminal, the base station can send the first information to the terminal.

[0118] As a possible implementation, as shown in FIG. 9, in a CU and DU separated architecture of the base station, the CU can send second information to the DU, and the DU can send the first information to the terminal device according to the second information after receiving the second information. The second information can be used to indicate the terminal type or the transmission type of the terminal device.

[0119] When the second information indicates the terminal type, the DU can determine the sending mode of the MAC PDU, that is, the DU determines and instructs the terminal device to send the MAC PDU containing the simplified or improved MAC header shown in the present application. For example, the DU can determine according to the terminal type that the terminal device communicating with the DU is an AIoT terminal or an IoT terminal, and thus the DU can send the first information to the terminal device to instruct the terminal device to send the simplified or improved MAC header. The CU can obtain the terminal type of the terminal device when the terminal device accesses. For example, the terminal type can include product model information or terminal identification information of the terminal device.

[0120] In addition, when the second information indicates the transmission type, the CU can determine the sending mode of the MAC PDU. The transmission type can be used to indicate or instruct the terminal device to send the simplified or improved MAC header. For example, the CU can determine according to the terminal type that the terminal is an AIoT terminal or an IoT terminal, and further, the CU can send the transmission type indication (i.e., the second information) to the DU. Correspondingly, the DU sends the first information to the terminal device according to the transmission type indication, which can be used to instruct the terminal device to adopt the single-bearer transmission mode, or to instruct the first MAC PDU to send the first MAC SDU in the single-bearer transmission mode, or to instruct the first MAC PDU to send the first MAC SDU in the single-bearer transmission mode. In addition, the transmission type indication can indicate that the terminal device sends the simplified or improved MAC header. For another example, the first information and the second information can both be the transmission type indication. The CU can determine according to the terminal type that the terminal device is an AIoT terminal or an IoT terminal, and further, the CU can send the transmission type indication to the DU, and the DU forwards the transmission type indication to the terminal device.

[0121] S102: The terminal device sends the first MAC PDU.

[0122] S102 can be understood as that the terminal device sends the first MAC PDU to the PHY layer, and the PHY layer can perform PHY layer processing such as scrambling and modulation on the first MAC PDU to obtain an air interface signal to be sent. In addition, S102 can also be understood as that the terminal device sends a signal to the base station through the air interface, and the signal can be obtained by the PHY layer of the terminal device according to the first MAC PDU.

[0123] S103: The base station receives the first MAC PDU from the terminal device.

[0124] S103 can be understood as that the PHY layer of the base station performs descrambling and demodulation on the signal transmitted over the air interface, and analyzes the first MAC PDU carried in the signal over the air interface. In addition, S103 can also be understood as that the base station receives the signal over the air interface, which is obtained by the PHY layer of the terminal device according to the first MAC PDU.

[0125] S104: The base station obtains the data carried in the first MAC PDU.

[0126] S104 can be understood as that the MAC layer entity of the base station processes the first MAC PDU, obtains the first MAC SDU, and sends the first MAC SDU to the upper layer. It can be understood that the MAC layer of the base station can analyze the first MAC PDU according to the format of the first MAC header to obtain the first MAC SDU. For example, assuming that the first MAC header consists of an R field, an F field, an E field, and an LCID, and occupies 1 byte of bits, after demodulating and decoding the signal over the air interface, the base station can obtain the bit information, and the base station can determine that the first MAC header occupies the first bit of the bit information according to the structure of the above-mentioned first MAC header, so as to determine the remaining bits of the bit information as the first MAC SDU, and perform subsequent processing, such as sending the remaining bits to the RLC layer by the MAC layer entity, and performing RLC layer processing by the RLC layer.

[0127] Based on the flow shown in FIG. 7, the MAC header of the MAC PDU generated by the terminal device can not carry a field for indicating the length of the MAC SDU to reduce the transmission overhead, and thus the power consumption of the terminal device can be reduced.

[0128] Optionally, the first MAC PDU can include a MAC CE, which can be located before the MAC SDU. As an optimization scheme for the MAC header, for example, as shown in FIG. 10, the first MAC header can include at least one of an N field, an E field, an F field, an L field, or an LCID. The F field, the L field, and the LCID can refer to the description of FIG. 4. The E field can be used to indicate whether there is an extension of the L field, for example, the E field takes a first value (such as 0) or is not present, which can represent that there is no extension of the L field, and can be understood as that the MAC header only carries one L field. Taking the first MAC header (a) shown in FIG. 10 as an example, the first MAC header occupies 1 byte, and there is no extended L field. Among them, the bits occupied by the LCID can be reduced, for example, the LCID can occupy 3 bits, and accordingly, the LCID can include 3 bits of the L field before the LCID, which can be used to indicate that the MAC PDU includes 9 bytes of the MAC SDU. For another example, the F field can be an optional field, or the F field can be part of the L field.

[0129] For another example, the E field takes the second value (e.g., 1), which can indicate that there is an extension of the L field, and it can be understood as the L field carrying the extension in the MAC header. For example, the first MAC header (b) in FIG. 10, Oct 2 contains the extended L field and the E field, and the extended L field can be used to support the indication of a longer MAC SDU length. In this case, the total length of the first MAC header (b) can be 2 bytes. Similarly, the first MAC header can also continue to increase the byte length based on the first MAC header (b) in FIG. 10, such as 3 bytes or 4 bytes, and the increased bytes can contain the extended L field and the E field to support the indication of a longer MAC SDU length.

[0130] In a possible embodiment, the terminal device can further send a second MAC PDU. The second MAC PDU can include a second MAC header and a second MAC SDU. The second MAC header can be a header or a subheader. The second MAC SDU can carry uplink data. The second MAC header can include a third field, which can be used to determine the length of the second MAC SDU. Accordingly, the base station can determine the location of the second MAC SDU.

[0131] For example, the third field can indicate the length of the second MAC SDU. Accordingly, the base station can know that the second MAC SDU in the second MAC PDU occupies bits of the length after the second MAC header. Therefore, the base station can take the bits of the length after the second MAC header as the second MAC SDU.

[0132] For another example, if the second MAC PDU further contains padding bits, the third field can indicate the length of the padding bits. Accordingly, the base station can know that the bit information corresponding to the second MAC PDU contains the second MAC header and the padding bits of the length. The remaining bits correspond to the second MAC SDU. Therefore, the base station can obtain the remaining bits as the second MAC SDU.

[0133] It can be understood that the second MAC SDU is related to the first MAC SDU. For example, as shown in FIG. 11, the first MAC SDU and the second MAC SDU belong to the same PDCP PDU (not excluding that other MAC SDUs also carry data in the same PDCP PDU) or RLC SDU. Alternatively, it can be said that the data carried by the first MAC SDU and the data carried by the second MAC SDU belong to the same radio bearer. Among them, the base station can configure the transmission resource of the MAC PDU for the terminal device through the resource configuration information, and if the size of the transmission resource is insufficient for the terminal device to carry the data in the same PDCP PDU (or the data in the same radio bearer) in the same MAC PDU for transmission, the terminal device can transmit the data through multiple MAC PDUs. For example, the terminal device can determine the first MAC PDU according to the size of the transmission resource, and the size of the transmission resource occupied by the first MAC PDU is equal to the size of the transmission resource configured by the first resource configuration information, that is, the remaining data is transmitted through other MAC PDUs. The base station can also configure the transmission resource of the subsequent MAC PDU through the resource configuration information.

[0134] That is, in the case of needing to perform segmented transmission on the RLC SDU, or in the case of the size of the configured transmission resource being smaller than the size of the RLC SDU of the terminal device, the RLC SDU needs to be transmitted through multiple MAC SDUs, that is, the terminal device can transmit multiple MAC PDUs, and the multiple MAC PDUs are used to carry multiple MAC SDUs respectively.

[0135] Among them, the multiple MAC PDUs include the first MAC PDU and the second MAC PDU, and optionally, other MAC PDUs are included between the first MAC PDU and the second MAC PDU. That is, in the case of needing to perform segmented transmission on the RLC SDU, or in the case of the size of the configured transmission resource being smaller than the size of the RLC SDU of the terminal device, the last MAC PDU (that is, the second MAC PDU) in the multiple MAC PDUs corresponding to the same RLC SDU transmitted by the terminal device can carry a third field, such as the L field or the field for indicating the length of the padding bit; if one or more RLC PDUs are completely included in the other MAC PDUs in the multiple MAC PDUs and no padding bit is needed, the other MAC PDUs can not carry the field for indicating the length of the MAC SDU, otherwise it can also need to be carried. In this way, the transmission overhead of the MAC PDU can be reduced.

[0136] As an example, the above-mentioned third field can be the L field in the second MAC header, or other fields, which are not specifically limited.

[0137] Optionally, the second MAC header can comprise an F field, which can be used to indicate whether the third field is included in the second MAC header. Further, if the third field is included, the F field can also be used to indicate the length of the third field. For example, the F field can take a first value to indicate that the second MAC header does not comprise the third field. For another example, the F field can take a second value to indicate that the second MAC header comprises the third field with a length of a certain length (e.g., 8 bits, 16 bits, or longer).

[0138] In a possible implementation, the third field can carry the length information of the second MAC SDU or the length information of the padding bits. For example, the length information of the second MAC SDU can be the byte length or the bit length occupied by the second MAC SDU, or can be an index value corresponding to the byte length or the bit length occupied by the second MAC SDU. For example, the length information of the padding bits can be the byte length or the bit length occupied by the padding bits, or can be an index value corresponding to the byte length or the bit length occupied by the padding bits. As an example, the third field can carry the one with smaller transmission overhead between the length information of the second MAC SDU or the length information of the padding bits, to further reduce the transmission overhead.

[0139] If the size of the transmission resource configured by the base station for the last MAC PDU through the resource configuration information is greater than the size of the transmission resource occupied by the MAC PDU, the MAC PDU can comprise padding bits, and the MAC PDU is the second MAC PDU, i.e., the MAC PDU can carry the third field described above, which is used to indicate the size of the MAC SDU or the padding bits. In addition, if the last MAC PDU carrying data in the same PDCP PDU does not comprise padding bits, the third field does not need to be carried in the MAC PDU, i.e., the length of the MAC SDU or the length of the padding bits does not need to be indicated, and the MAC PDU can refer to the first MAC PDU, i.e., the MAC PDU does not carry the field used to indicate the length of the MAC SDU (i.e., the MAC header does not carry the L field).

[0140] In addition, the MAC SDU carrying data in the same PDCP PDU is at least 3, and the second last MAC PDU and the MAC PDU before it can refer to the sending mode of the first MAC PDU in the present application, i.e., the MAC PDU does not carry the field used to indicate the length of the MAC SDU (i.e., the MAC header does not carry the L field).

[0141] It can be understood that the embodiments provided in the present application can also be applied in the scenario where multiple RLC SDUs exist. Specifically, whether the flowcharts of FIG. 7 or FIG. 9 are applied in the scenario where multiple RLC SDUs exist can be determined according to the size of the time-frequency resource configured by the base station. Specifically, taking two consecutive RLC SDUs as an example, if the size of the transmission resource occupied by the MAC PDU corresponding to the former RLC SDU is the same as the size of the transmission resource configured by the base station, i.e., the former RLC SDU does not need to fill in bits, it can be considered that the MAC PDU corresponding to the former RLC SDU is the first MAC PDU described in the present application, and if the latter RLC SDU needs to fill in bits, i.e., the to-be-transmitted resource is greater than the latter RLC SDU, it can be considered that the last MAC PDU corresponding to the latter RLC SDU is the second MAC PDU. It can also be understood that the non-last MAC PDU in the MAC PDU corresponding to the latter RLC SDU can be the third MAC PDU. It can also be understood that for n>2 consecutive RLC SDUs, if the first to the n-1th RLC SDUs all satisfy that the size of the transmission resource occupied by the MAC PDU corresponding to each RLC SDU is the same as the size of the transmission resource configured by the corresponding base station, and the n th RLC SDU needs to fill in bits, it can be considered that the RLC PDU corresponding to the first RLC SDU can generate the first MAC PDU described in the present application, and the last MAC PDU corresponding to the n th RLC SDU is the second MAC PDU described in the present application, and the other MAC PDUs between the first MAC PDU and the second MAC PDU can be the third MAC PDU described in the present application.

[0142] In addition, in the case where the MAC PDU corresponding to the former RLC SDU needs to fill in bits in the two consecutive RLC SDUs, the scenario where the first MAC PDU and the second MAC PDU coexist in the embodiments of the present application is not used.

[0143] Based on the same technical concept, the embodiments of the present application provide a communication device, which comprises a module or unit or means corresponding to the method steps in the method embodiments described above, and the functions or units or means can be implemented by software or by hardware, or by executing corresponding software by hardware.

[0144] For example, referring to FIG. 12, the device 1200 can comprise a processing module 1201 and a transceiver module 1202.

[0145] Optionally, the transceiver 1202 can include a transmitter module and / or a receiver module. The transmitter module is configured to perform the transmitting operations in the above method embodiments. The receiver module is configured to perform the receiving operations in the above method embodiments.

[0146] It is noted that the communication apparatus 1200 can include the transmitter module but not the receiver module. Alternatively, the communication apparatus 1200 can include the receiver module but not the transmitter module. Whether the communication apparatus 1200 includes the transmitter module and the receiver module can depend on whether the communication apparatus 1200 performs the transmitting operation and the receiving operation in the above-described schemes.

[0147] The processing module 1201 is configured to perform data processing. The transceiver 1202 can realize corresponding communication functions.

[0148] Optionally, the communication apparatus 1200 can further include a storage module, which can be configured to store instructions and / or data. The processing module 1201 can read the instructions and / or data in the storage module, so that the communication apparatus 1200 implements the above method embodiments.

[0149] For example, the communication apparatus 1200 can be a first communication apparatus or a component configurable to the first communication apparatus. The first communication apparatus can be, for example, a terminal device (e.g., the terminal device in FIG. 7 or FIG. 9). The processing module 1201 is configured to perform processing-related operations of the terminal device in the above method embodiments. The transceiver 1202 is configured to perform transmitting- and / or receiving-related operations of the terminal device in the above method embodiments.

[0150] For example, when used to implement the actions of the terminal device in FIG. 7, the processing module 1201 can be configured to perform S101, i.e., obtaining the first MAC PDU. The transceiver 1202 can be configured to perform S102, i.e., transmitting the first MAC PDU.

[0151] For another example, when used to implement the steps performed by the terminal device in FIG. 9, the transceiver 1202 can be configured to receive the first information and transmit the first MAC PDU. The processing module 1201 can be configured to generate the first MAC PDU according to the first information.

[0152] In addition, the communication apparatus 1200 can be a second communication apparatus or a component configurable to the second communication apparatus. The second communication apparatus can be, for example, a network device (e.g., the base station, the CU, the DU, or the RU in FIG. 7 or FIG. 9). The processing module 1201 is configured to perform processing-related operations of the network device in the above method embodiments. The transceiver 1202 is configured to perform transmitting- and / or receiving-related operations of the network device in the above method embodiments.

[0153] For example, in a process for implementing the actions of the base station shown in FIG. 7: the transceiver module 1202 can be configured to receive the first MAC PDU. The processing module 1201 can be configured to determine the data carried by the first MAC PDU.

[0154] For another example, in a process for implementing the steps performed by the DU shown in FIG. 9: the transceiver module 1202 can be configured to receive the second information from the CU and send the first information to the terminal device. The processing module 1201 can be configured to determine the first information according to the second information.

[0155] For another example, in a process for implementing the steps performed by the CU shown in FIG. 9: the transceiver module 1202 can be configured to send the second information to the DU. The processing module 1201 can be configured to determine the second information according to the terminal type or the transmission type of the terminal device.

[0156] It should be understood that all related contents of the steps involved in the above method embodiments can be cited from the function description of the corresponding function modules, which will not be repeated here.

[0157] The processing module 1201 in the above embodiments can be implemented by at least one processor or processor-related circuit. The transceiver module 1202 can be implemented by a transceiver or transceiver-related circuit. The transceiver module 1202 can also be referred to as a communication module or a communication interface.

[0158] Another structural schematic diagram of the communication device according to the embodiments of the present application is shown below. As shown in FIG. 13, the embodiments of the present application further provide a communication device 1300, which comprises:

[0159] at least one processor 1301; and a communication interface 1303 connected with the at least one processor 1301; the at least one processor 1301 executes instructions stored in at least one memory 1302, so that the device performs the method steps in the above method embodiments through the communication interface 1303.

[0160] Optionally, the at least one memory 1302 is located outside the device 1300.

[0161] Optionally, the device 1300 comprises the at least one memory 1302, which is connected with the at least one processor 1301, and the memory 1302 stores instructions executable by the at least one processor 1301. FIG. 13 shows that the memory 1302 is optional for the device 1300 with a dashed line.

[0162] The processor 1301 and the memory 1302 can be coupled through an interface circuit or integrated together, which is not limited here.

[0163] The specific connection medium between the processor 1301, the memory 1302 and the communication interface 1303 in the embodiments of the present application is not limited. In FIG. 13, the processor 1301, the memory 1302 and the communication interface 1303 are connected through a bus 1304, which is represented by a thick line in FIG. 13, and the connection mode between other components is only schematically illustrated and is not limited. The bus can be divided into an address bus, a data bus, a control bus and the like. For convenience of representation, one thick line is used in FIG. 13, but it is not meant that there is only one bus or only one type of bus.

[0164] When the communication apparatus 1300 is a first communication apparatus, the first communication apparatus can include a processor, a memory and a transceiver. The memory can store computer program code, and the transceiver includes a transmitter and a receiver.

[0165] The processor is mainly used for processing communication protocols and communication data, for example, controlling the first communication apparatus, executing software programs and processing data of the software programs and the like. The memory is mainly used for storing software programs and data. The transmitter is used for sending signals to other communication apparatuses or devices, and the receiver is used for receiving signals from other communication apparatuses or devices.

[0166] When the communication apparatus 1300 is a chip in the first communication apparatus, the chip can include a processor, a memory and a transceiver. The transceiver can be an input-output circuit or a communication interface. The processor can be an integrated processing module or a microprocessor or an integrated circuit on the chip. The transmission operation of the first communication apparatus in the method embodiments can be understood as the output of the chip, and the reception operation of the first communication apparatus in the method embodiments can be understood as the input of the chip.

[0167] Similarly, when the communication apparatus 1300 is a second communication apparatus, the second communication apparatus can include a processor, a memory and a transceiver. The memory can store computer program code, and the transceiver includes a transmitter and a receiver.

[0168] The processor is mainly used for processing communication protocols and communication data, for example, controlling the second communication apparatus, executing software programs and processing data of the software programs and the like. The memory is mainly used for storing software programs and data. The transmitter is used for sending signals to other communication apparatuses or devices, and the receiver is used for receiving signals from other communication apparatuses or devices.

[0169] When the communication apparatus 1300 is a chip in the second communication apparatus, the chip can include a processor, a memory and a transceiver. The transceiver can be an input output circuit or a communication interface. The processor can be a processing module integrated on the chip or a microprocessor or an integrated circuit. The sending operation of the second communication apparatus in the method embodiments can be understood as the output of the chip, and the receiving operation of the second communication apparatus in the method embodiments can be understood as the input of the chip.

[0170] It should be understood that the processor mentioned in the embodiments of the present application can be implemented by hardware or software. When implemented by hardware, the processor can be a logic circuit, an integrated circuit, etc. When implemented by software, the processor can be a general-purpose processor which is implemented by reading software codes stored in a memory.

[0171] For example, the processor can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0172] It should be appreciated that the memory mentioned in the embodiments of the present application can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically EPROM (EEPROM) or a flash memory. The volatile memory can be a random access memory (RAM) used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM) and direct rambus RAM (DR RAM).

[0173] It should be noted that when the processor is a general processor, a DSP, an ASIC, a FPGA or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, the memory (storage module) can be integrated in the processor.

[0174] It should be noted that the memory described herein is intended to include, but not limited to, these and any other suitable types of memory.

[0175] Based on the same technical concept, the embodiments of the present application also provide a computer readable storage medium, including programs or instructions, when the programs or instructions run on the computer, so that the method in the above method embodiment is executed.

[0176] The embodiments of the present application further provide a chip or a chip system, which comprises a circuit (such as an analog circuit and / or a logic circuit; or it is understood that the chip system comprises one or more processors, and the one or more processors can comprise a circuit, etc.), or it is understood that the chip comprises a processor. The circuit or the processor is coupled with a memory, and is used to execute a computer program or an instruction stored in the memory, so that the method shown in FIG. 3, FIG. 4 or various embodiments of the present application is implemented. The chip or the chip system can further comprise an input / output interface. For example, taking the chip as an example, the chip can receive information from other modules (such as a radio frequency or an antenna, etc.) in the terminal device through the input / output interface, and the information can be sent by a base station or other communication devices to the terminal device. Alternatively, the chip can send information to other modules (such as a radio frequency or an antenna, etc.) in the terminal device through the input / output interface, and the information can be sent by the terminal device to the base station or other communication devices.

[0177] Based on the same technical concept, the embodiments of the present application further provide a computer program product, which comprises instructions, when the instructions are executed on a computer, so that the method in the above method embodiments is executed.

[0178] Based on the same technical concept, the embodiments of the present application further provide a communication system, which can comprise a first communication device and a second communication device. Wherein, the first communication device can be used to implement the method in the above method embodiments implemented by the first communication device, and the second communication device can be used to implement the method in the above method embodiments implemented by the second communication device. For example, the first communication device is used to execute the actions implemented by the terminal device in the flow shown in FIG. 7 or FIG. 9, and the second communication device is used to execute the actions implemented by the base station, the CU or the DU in the flow shown in FIG. 7 or FIG. 9.

[0179] Based on the same technical concept, the embodiments of the present application further provide a communication system, which can comprise a first communication device and a second communication device. For example, the first communication device is a terminal device, and the second communication device is a base station, a CU, a DU, an RU or a reader, etc.

[0180] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system or a computer program product. Therefore, the present application can adopt a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware aspects. Moreover, the present application can adopt a computer program product implemented on one or more computer usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program codes.

[0181] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks.

[0182] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks.

[0183] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks.

[0184] In the description of the present application, the words "first", "second", etc. are used only to distinguish descriptions, and cannot be understood as indicating or implying relative importance, nor indicating or implying sequence. It should be noted that the order of appearance of first, second, etc. is not limited in the present application, for example, second can appear first and first can appear second, which is not limited in the present application.

[0185] In the description of the present application, "at least one" means one or more, and more means two or more. "At least one of the following" or similar expressions means any combination of these items, including any combination of single or multiple items. For example, at least one of a, b, or c can mean a, b, c, a and b, a and c, b and c, or a and b and c, wherein a, b, and c can be single or multiple. In the description of the present application, " / " represents "or", for example, a / b represents a or b.

Claims

1. A communication method characterized by comprising: The application is applied to a terminal device or a chip of the terminal device, and includes: obtaining a first media access control (MAC) protocol data unit, wherein the first MAC protocol data unit comprises a first MAC header and a first service data unit, the first MAC header does not carry a first field, and the first field is used to indicate the length of the first service data unit; sending the first MAC protocol data unit.

2. The method of claim 1, wherein, The terminal device is an Internet of Things terminal device.

3. The method of claim 1 or 2, wherein, The first MAC protocol data unit comprises one service data unit.

4. The method of any one of claims 1-3, wherein, The terminal device sends the first MAC protocol data unit in a single-carry transmission mode.

5. The method of any one of claims 1-4, wherein, The first MAC protocol data unit comprises a second field, and the second field is used to indicate whether the first MAC protocol data unit carries the first field.

6. The method of any one of claims 1-5, wherein, The method further comprises: receiving first resource configuration information, which is used to configure the transmission resource of the first MAC protocol data unit, and the size of the transmission resource is equal to the size of the resource occupied by the first MAC protocol data unit.

7. The method of any one of claims 1-6, wherein, The method further comprises: sending a second MAC protocol data unit, wherein the second MAC protocol data unit comprises a second MAC header, a second service data unit and padding bits, the second MAC header carries a third field, and the third field is used to indicate the length of the second service data unit.

8. The method of claim 7, wherein, The third field is used to indicate at least one of the following information: the length information of the second service data unit; the length information of the padding bits.

9. The method of any one of claims 1-8, wherein, The method further comprises: receiving first information, which is used to determine the sending of the first MAC information.

10. A communication method characterized by comprising: The method comprises: receiving a first MAC protocol data unit, wherein the first MAC protocol data unit comprises a first MAC header and a first service data unit, the first MAC header does not carry a first field, and the first field is used to indicate the length of the first service data unit; obtaining the data carried by the first service data unit.

11. The method of claim 10, wherein, The terminal device is an Internet of Things terminal device.

12. The method of claim 10 or 11, wherein, The first MAC protocol data unit comprises one service data unit.

13. The method of any one of claims 10-12, wherein, The terminal device sends the first MAC protocol data unit in a single-carry transmission mode.

14. The method of any one of claims 10-13, wherein, The first MAC protocol data unit comprises a second field, and the second field is used to indicate whether the first MAC protocol data unit carries the first field.

15. The method of any one of claims 10-14, wherein, The method further comprises: sending first resource configuration information, which is used to configure the transmission resource of the first MAC protocol data unit, and the size of the transmission resource is equal to the size of the resource occupied by the first MAC protocol data unit.

16. The method of any one of claims 10-15, wherein, The method further comprises: receiving a second MAC protocol data unit, wherein the second MAC protocol data unit comprises a second MAC header, a second service data unit and padding bits, the second MAC header carries a third field, and the third field is used to indicate the length of the second service data unit.

17. The method of claim 16, wherein, The third field is used to indicate at least one of the following information: the length information of the second service data unit; the length information of the padding bits.

18. The method of any one of claims 10-17, wherein, The method further comprises: transmitting first information, the first information being used for determining that the Internet of Things device transmits the first MAC information.

19. The method of any one of claims 10-18, wherein, The method is applied to a distributed unit, and the method further comprises: receiving second information from a central unit, the second information being used for indicating a device type or a transmission type of the terminal device; The transmitting first information comprises: determining the transmitting of the first information according to the device type or the transmission type of the terminal device.

20. A communications device, characterized by comprising units or modules for performing the method according to any one of claims 1-9, or comprising units or modules for performing the method according to any one of claims 10-19.

21. A communications device, characterized by comprising a processor for executing computer programs or instructions to implement the method according to any one of claims 1-9, or to implement the method according to any one of claims 10-19.

22. A computer-readable storage medium, characterized in that, The storage medium stores computer programs or instructions, and when the computer programs or instructions are executed by a communication device, the method according to any one of claims 1-9 is implemented, or the method according to any one of claims 10-19 is implemented.

23. A computer program product, characterised in that, When a computer program product is executed by a computer, the computer executes the method according to any one of claims 1-9, or executes the method according to any one of claims 10-19.

24. A chip system, characterized by comprising a logic circuit; The logic circuit is used for executing computer executable programs, so that a device installed with the chip system is used for executing the method according to any one of claims 1-9, or executing the method according to any one of claims 10-19.

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