Patent Description:
In new radio (new radio, NR), after establishing a connection to a cell, a terminal device is in a radio resource control (radio resource control, RRC) connected mode. After that, if signal quality of a link between the terminal device and the cell is continuously relatively poor, the terminal device triggers a link failure, and triggers an RRC connection reestablishment process. The RRC connection reestablishment process is to enable the terminal device to find another cell in which communication can be normally performed, and reestablish a connection. After finding a suitable cell, the terminal device initiates the RRC connection reestablishment process in the cell.

However, when performing RRC connection reestablishment, the terminal device in NR performs two times of random access (random access channel, RACH), causing a waste of RACH resources. The article by <NPL>), , refers to RRC connection release enhancements The <CIT> refers a method and a device for processing data transmission.

This application provides a radio resource control RRC message sending method and an apparatus, to save RACH resources in an RRC connection reestablishment process. The present application is defined in the appended independent claims. Further implementations are disclosed in the pending independent claims.

According to a first aspect, this application provides an RRC message sending method, and the method may be implemented by a distributed unit DU. According to the method, the DU determines not to start an RLC polling mechanism when sending an RRC message to a terminal apparatus. Therefore, when sending the RRC message, the DU may set a polling bit in a header of an RLC PDU carrying the RRC message to be in an inactive state. When the polling bit is in the inactive state, it indicates that the RLC polling mechanism is not started, and after receiving the RLC message, the terminal apparatus does not feed back an RLC status report to the DU. Specifically, if the polling bit is set to <NUM>, it indicates an active state. In this case, the DU may set the polling bit to <NUM> when sending the RRC message.

According to the foregoing design, the DU may not start the RLC polling mechanism when sending the RRC message. Therefore, after receiving the RRC message, the terminal apparatus does not feed back the RLC status report based on the RLC polling mechanism, and therefore does not need to initiate a random access procedure to send the RLC status report based on an uplink grant obtained through the random access procedure, thereby saving RACH resources.

In a possible design, after determining that the RRC message is the first RRC message sent through a first signaling channel, the DU may determine not to start the RLC polling mechanism when sending the RRC message to the terminal apparatus. The first signaling channel may be a signaling channel between the terminal apparatus and the DU and that is resumed through an RRC reestablishment process. After the signaling channel is resumed, the DU does not start the RLC polling mechanism when the DU sends the first RRC message through the signaling channel. For example, the first signaling channel may be an SRB <NUM>. According to this design, the DU can autonomously determine not to start the RLC polling mechanism when specific RRC messages are sent.

In a possible design, after receiving first information sent by a CU, the DU may determine not to start the RLC polling mechanism when sending the RRC message to the terminal apparatus. The RRC message and the first information may be sent through a same message, namely, a first message. Further, the first message may be a downlink RRC transmission message or a terminal context setup request message. In addition, the RRC message and the first information may alternatively be separately sent through different messages. For example, the CU may send the first information to the DU through a downlink RRC transmission message or a terminal context setup request message, and send the RRC message to the DU through another downlink RRC transmission message or another terminal context setup request message.

In a possible design, the first information may be specifically used to indicate the DU to set, when the DU sends the RRC message to the terminal apparatus, a polling bit in a header of an RLC protocol data unit PDU carrying the RRC message to be in an inactive state, or used to indicate the DU not to trigger polling when the DU sends the RRC message to the terminal apparatus.

In a possible design, the DU may further send a resource indication to the terminal apparatus, where the resource indication may be used to indicate a first uplink transmission resource to the terminal apparatus, and the first uplink transmission resource may be used by the terminal apparatus to request an uplink transmission resource (for example, the terminal apparatus sends an uplink transmission resource request to the DU based on the first uplink transmission resource, and the DU may send the uplink transmission resource request to the CU or a network device to which the DU belongs). The uplink transmission resource may be used for data transmission.

In a possible design, the RRC message may be an RRC reestablishment message. Alternatively, the RRC message may be an RRC reestablishment message and an RRC reconfiguration message. Alternatively, the RRC message may be an RRC resume message.

The method may be further implemented by a centralized unit CU. According to the method, the CU may generate first information, and the first information may be used to indicate a distributed unit DU not to start an RLC polling mechanism when the DU sends an RRC message to a terminal apparatus.

According to the foregoing design, the CU may indicate, by using the first information, the DU not to start the RLC polling mechanism when the DU sends the RRC message. Therefore, after receiving the RRC message, the terminal apparatus does not feed back an RLC status report based on the RLC polling mechanism, and therefore does not need to initiate a random access procedure to send the RLC status report based on an uplink grant obtained through the random access procedure, thereby saving RACH resources.

In a possible design, the CU may be further configured to: generate the RRC message, include the RRC message and the first information in a first message, and send the first message to the DU, where the first information is used to indicate the DU not to start the RLC polling mechanism when the DU sends the RRC message. In this design, the RRC message and the first information corresponding to the RRC message are sent through one message, thereby reducing interaction between the CU and the DU, and improving efficiency of sending the RRC message.

In a possible design, the first message is a downlink RRC transmission message or a terminal context setup request message. In addition, the CU may alternatively separately send the first information and the RRC message to the DU. For example, the CU may send the first information to the DU through a downlink RRC transmission message or a terminal context setup request message, and send the RRC message to the DU through another downlink RRC transmission message or another terminal context setup request message. In this design, the CU is enabled to implement, through a message in an existing RRC connection reestablishment process, the RRC message sending method provided in embodiments of this application. Therefore, in terms of implementation, a relatively small change is made to the existing RRC reestablishment process, and the implementation is relatively easy.

In a possible design, the first information may be specifically used to indicate the DU to set, when the DU sends the RRC message to the terminal apparatus, a polling bit in a header of an RLC protocol data unit PDU carrying the RRC message to be in an inactive state, or used to indicate the DU not to trigger polling when the DU sends the RRC message to the terminal apparatus. This design can improve indication efficiency, so that the DU can efficiently determine, based on the first information, not to start the RLC polling mechanism.

According to a second aspect, this application provides another RRC message sending method, and the method may be implemented by a network device. According to the method, the network device sends an RRC message and a resource indication to a terminal apparatus, where a polling bit in a header of an RLC PDU carrying the RRC message is set to be in an active state, the resource indication may be used to indicate a first uplink transmission resource, the first uplink transmission resource may be used by the terminal apparatus to request a second uplink transmission resource, and the second uplink transmission resource may be used by the terminal apparatus to send an RLC status report to the network device.

If the method is implemented by a terminal apparatus, the terminal apparatus may receive an RRC message and a resource indication from a network device, a polling bit in a header of an RLC PDU carrying the RRC message is set to be in an active state, and the resource indication may be used to indicate a first uplink transmission resource. Then, the terminal apparatus may determine, based on the polling bit, that an RLC status report needs to be sent to the network device. The terminal apparatus sends the RLC status report to the network device based on the second uplink transmission resource, where the second uplink transmission resource is a transmission resource that the terminal apparatus requests, based on the first uplink transmission resource, the network device to allocate.

According to this design, the terminal apparatus feeds back the RLC status report by using the second uplink transmission resource. The second uplink transmission resource is requested by the terminal apparatus from the network device based on the first uplink transmission resource indicated by the network device. Therefore, the terminal apparatus can obtain an uplink grant without initiating random access, thereby saving RACH resources.

In a possible design, if the RRC message is transmitted through a signaling radio bearer SRB <NUM> between the terminal apparatus and the network device, and the RLC status report is the first status report after the SRB <NUM> is resumed, the method further includes: The terminal apparatus triggers sending of the RLC status report after preset duration from a time point at which the terminal apparatus determines that the RLC status report needs to be sent to the network device. The preset duration may be duration preconfigured by the network device or agreed on in advance. For example, the preset duration may be <NUM> milliseconds. According to this design, the preset duration may be used by the terminal apparatus to parse the resource indication and request the second uplink transmission resource from the network device. Therefore, the RLC status report may be sent by using the second uplink transmission resource, to avoid initiating random access.

In a possible design, after the terminal apparatus determines, based on the polling bit, that the RLC status report needs to be sent to the network device, the method further includes: The terminal apparatus triggers a random access procedure, where the random access procedure is used by the terminal apparatus to request an uplink transmission resource from the network device, and the uplink transmission resource is used to send the RLC status report. That the terminal apparatus sends the RLC status report to the network device based on the second uplink transmission resource includes: Before determining, based on the random access procedure, an uplink transmission resource allocated by the network device, the terminal apparatus sends the RLC status report to the network device based on the second uplink transmission resource, and stops performing the random access procedure.

In a possible design, the RRC message includes at least one of the following messages: an RRC reestablishment message, or an RRC reestablishment message and an RRC reconfiguration message, or an RRC resume message.

According to a third aspect, this application provides a communication apparatus. For example, the communication apparatus is the CU, the DU, the network device, or the terminal apparatus described above. The communication apparatus may be configured to perform the method according to any one of the first aspect or the possible implementations of the first aspect, or configured to perform the method according to any one of the second aspect or the possible implementations of the second aspect. Specifically, the communication apparatus may include a module configured to perform the method according to any one of the first aspect or the possible implementations of the first aspect or any one of the second aspect or the possible implementations of the second aspect. For example, the communication apparatus includes a processing module and a communication module that are coupled to each other.

If the communication apparatus is a CU, a processing module may be configured to generate first information, where the first information is used to indicate a DU not to start a radio link layer control protocol RLC polling mechanism when the DU sends an RRC message to a terminal apparatus. A communication module may be configured to send the first information to the distributed unit DU.

In a possible design, the processing module may be further configured to generate the RRC message. When sending the first information to the distributed unit DU, the communication module may send a first message to the DU, where the first message includes the RRC message and the first information.

In a possible design, the first message is a downlink RRC transmission message. Alternatively, the first message is a terminal context setup request message.

In a possible design, the first information is specifically used to indicate the DU to set, when the DU sends the RRC message to the terminal apparatus, a polling bit in a header of an RLC protocol data unit PDU carrying the RRC message to be in an inactive state, or the first information is specifically used to indicate the DU not to trigger polling when the DU sends the RRC message to the terminal apparatus.

In a possible design, the first information is carried in a downlink RRC transmission message. Alternatively, the first information is carried in a terminal context setup request message.

If the communication apparatus is a DU, a processing module may be configured to determine not to start an RLC polling mechanism when an RRC message is sent. A communication module may be configured to set, when sending the RRC message to a terminal apparatus, a polling bit in a header of an RLC PDU carrying the RRC message to be in an inactive state.

In a possible design, the processing module may be specifically configured to: when determining that the RRC message is the first RRC message sent to the terminal apparatus through a first signaling channel, determine not to start the RLC polling mechanism when the RRC message is sent; or the processing module may be specifically configured to: when determining that first information sent by a CU is received, determine not to start the RLC polling mechanism when the RRC message is sent, where the first information is used to indicate the DU not to start the RLC polling mechanism when the DU sends the RRC message.

In a possible design, the first information is specifically used to indicate the DU to set, when the DU sends the RRC message to the terminal apparatus, a polling bit in a header of an RLC PDU carrying the RRC message to be in an inactive state, or the first information is specifically used to indicate the DU not to trigger polling when the DU sends the RRC message to the terminal apparatus.

In a possible design, the communication module may be further configured to receive a first message from the CU, where the first message includes the RRC message and the first information.

In a possible design, the communication module may be further configured to indicate a first uplink transmission resource to the terminal apparatus, where the first uplink transmission resource is used by the terminal apparatus to request an uplink transmission resource from the DU.

If the communication apparatus is a network device, a processing module may be configured to generate an RRC message and a resource indication. The communication module may be configured to send the RRC message and the resource indication to the terminal apparatus, where a polling bit in a header of an RLC PDU carrying the RRC message is set to be in an active state, and the resource indication is used to indicate a first uplink transmission resource.

If the communication apparatus is a terminal apparatus, a processing module may be configured to determine, based on polling indication information in a header of an RLC PDU carrying the RRC message, not to send an RLC status report to the network device.

In a possible design, the processing module may be configured to determine, based on the polling indication information in the header of the RLC PDU carrying the RRC message, to send the RLC status report to the network device, and configured to generate the RLC status report. The communication module may be configured to: request an uplink transmission resource from the network device based on a resource indication sent by the network device, and send the RLC status report to the network device based on the uplink transmission resource indicated by the network device.

In a possible design, if the RRC message is transmitted through a signal radio bearer SRB <NUM> between the terminal apparatus and the network device, and the RLC status report is the first status report after the SRB <NUM> is resumed, the processing module may trigger sending of the RLC status report after preset duration from a time point at which the processing module determines that the RLC status report needs to be sent to the network device.

In a possible design, after determining that the RLC status report needs to be sent to the network device, the processing module may further trigger a random access procedure, where the random access procedure is used by the terminal apparatus to request an uplink transmission resource from the network device, and the uplink transmission resource is used to send the RLC status report. Before determining, based on the random access procedure, an uplink transmission resource allocated by the network device, the communication module may send the RLC status report to the network device based on the second uplink transmission resource, and stop performing the random access procedure.

According to a fourth aspect, a communication system is provided. The communication system may include the communication apparatus described in the third aspect, and the communication apparatus may be configured to perform the method described in any one of the first aspect or the possible designs of the first aspect, or configured to perform the method described in any one of the second aspect or the possible designs of the second aspect.

According to a fifth aspect, a computer-readable storage medium is provided. The computer-readable storage medium stores instructions, and when the instructions are run on a computer, the computer is enabled to perform the method described in any one of the first aspect or the possible designs of the first aspect, or configured to perform the method described in any one of the second aspect or the possible designs of the second aspect.

According to a sixth aspect, a computer program product including instructions is provided. When the computer program product runs on a computer, the computer is enabled to perform the method described in any one of the first aspect or the possible designs of the first aspect, or configured to perform the method described in any one of the second aspect or the possible designs of the second aspect.

According to a seventh aspect, an embodiment of this application provides a chip system. The chip system includes a processor, and may further include a memory, configured to perform the method described in any one of the first aspect or the possible designs of the first aspect, or configured to perform the method described in any one of the second aspect or the possible designs of the second aspect. The chip system may include a chip, or may include a chip and another discrete component.

For beneficial effects of the second aspect to the thirteenth aspect and the implementations thereof, refer to the descriptions of the beneficial effects of the method according to the first aspect and the possible designs thereof, or the method according to the second aspect and the possible designs thereof.

A specific operation method in a method embodiment may also be applied to an apparatus embodiment or a system embodiment.

The following explains terms in this application.

At least one means one or more, that is, including one, two, three, or more.

A plurality of means two or more, that is, including two, three, or more.

Carrying may mean that a message is used to carry information or data, or may mean that a message includes information.

RRC connection reestablishment may also be referred to as RRC reestablishment or RRC reconnection. Before initiating the RRC connection reestablishment, a terminal device may obtain an uplink grant through a random access procedure, and the uplink grant is used to send an RRC connection reestablishment request. In addition, after the terminal device receives an RRC reestablishment (reestablishment) message, an RRC reconfiguration (reconfiguration) message, or an RRC resume (resume) message that is sent by a base station, the terminal device determines, based on a polling (polling) bit in the RRC reestablishment message, the RRC reconfiguration message, or the RRC resume message, to send a radio link layer control protocol (radio link control, RLC) status report to the base station. The polling bit is set to be in an active state by the base station (for example, when the polling bit is set to <NUM>, it indicates that the polling bit is in the active state, and it indicates that the terminal device needs to feed back the RLC status report). In this case, to send the RLC status report, the terminal device still obtains an uplink grant through the random access procedure. Therefore, currently, in an RRC connection reestablishment process, the terminal device initiates two times of random access.

In this application, an RRC message includes the RRC reestablishment message, the RRC reconfiguration message, or the RRC resume message. Alternatively, the RRC message may include the RRC reestablishment message and the RRC reconfiguration message.

A signaling channel may also be referred to as a signaling radio bearer (signal radio bearers, SRB), and is a transmission channel of control signaling. A network device may send signaling such as the RRC message to the terminal device through the signaling channel. At least one signaling channel may be maintained between the network device and the terminal device, and a plurality of signaling channels may also be maintained between the network device and the terminal device.

In this application, a polling bit is a bit in a header of an RLC protocol data unit (protocol data unit, PDU) when the network device sends the RRC message to the terminal device through RLC. When the bit is set to be in an active state, the terminal device receiving the RRC message needs to feed back the RLC status report to the network device. On the contrary, when the polling bit is set to be in an inactive state, the terminal device does not feed back the RLC status report to the network device after receiving the RRC message.

In the step shown in S102, if a value is set to <NUM>, it indicates that the polling bit is in the active state, and a DU <NUM> may set a polling bit of an RLC PDU carrying the RRC message to <NUM> when sending the RRC message.

The following describes the embodiments of this application in detail with reference to the accompanying drawings. First, a wireless communication system provided in the embodiments of this application is described. An RRC message sending method provided in this application may be applied to the system. Then, the RRC message sending method provided in the embodiments of this application is described. Finally, an apparatus provided in the embodiments of this application is described.

As shown in <FIG>, a wireless communication system <NUM> provided in an embodiment of this application may include a terminal device <NUM> and a network device <NUM>. It should be understood that the wireless communication system <NUM> provided in this embodiment of this application is applicable to both a low-frequency scenario (sub <NUM>) and a high-frequency scenario (above <NUM>). An application scenario of the wireless communication system <NUM> provided in this embodiment of this application includes but is not limited to: a global system for mobile communications (Global System of Mobile communication, GSM) system, a code division multiple access (Code Division Multiple Access, CDMA) system, a wideband code division multiple access (Wideband Code Division Multiple Access, WCDMA) system, a general packet radio service system (General Packet Radio Service, GPRS), a long term evolution (Long Term Evolution, LTE) system, an LTE frequency division duplex (Frequency Division Duplex, FDD) system, an LTE time division duplex (Time Division Duplex, TDD), a universal mobile telecommunications system (Universal Mobile Telecommunication System, UMTS), a worldwide interoperability for microwave access (Worldwide Interoperability for Microwave Access, WiMAX) communication system, a future 5th generation (5th Generation, <NUM>) system, an NR communication system, or the like.

The terminal device <NUM> shown above may be a device such as user equipment (user equipment, UE), a terminal (terminal), a mobile station (mobile station, MS), or a mobile terminal (mobile terminal). The terminal device <NUM> can communicate with one or more network devices of one or more communication systems, and accepts a network service provided by a network device. The network device herein includes but is not limited to the network device <NUM> shown in the figure. For example, in this embodiment of this application, the terminal device <NUM> may be a mobile phone (which is also referred to as a "cellular" phone) or a computer having a mobile terminal. Alternatively, the terminal device <NUM> may be a portable, pocket-sized, handheld, computer built-in, or in-vehicle mobile apparatus. Alternatively, the terminal device <NUM> may be a communication chip having a communication module.

The network device <NUM> may include a base station (base station, BS), or include a base station, a radio resource management device configured to control the base station, and the like. The network device <NUM> may be a relay station (relay device), an access point, a vehicle-mounted device, a wearable device, a base station in a future <NUM> network, a base station in a future evolved public land mobile network (public land mobile network, PLMN), an NR base station, or the like. This is not limited in this embodiment of this application.

As shown in <FIG>, another wireless communication system provided in this application may include a centralized unit (centralized unit, CU) <NUM> and a distributed unit (distribute unit, DU) <NUM>. The CU <NUM> may include a packet data convergence protocol (packet data convergence protocol, PDCP) layer and an RRC layer. The DU <NUM> may include an RLC layer, a media access control (media access control, MAC) layer, and a port physical layer (port physical layer, PHY). In an RRC reestablishment process, the CU <NUM> may be specifically configured to generate an RRC message that needs to be sent to a terminal device <NUM>, and send the RRC message to the RLC layer of the DU <NUM>. The DU <NUM> sends the RRC message to the terminal device <NUM> through the RLC layer. Because the DU <NUM> has a function of the RLC layer, when a polling bit in a header of an RLC PDU sent by the DU <NUM> to the terminal device <NUM> is set to be in an active state, the terminal device <NUM> sends an RLC status report to the DU <NUM> after receiving the RLC PDU.

It should be understood that the CU <NUM> and/or the DU <NUM> may be used as components/a component of the network device <NUM> shown in <FIG>. Alternatively, the CU <NUM> and/or the DU <NUM> may be used as communication apparatuses/a communication apparatus independent of the network device <NUM>.

The wireless communication system <NUM> may be applied to an NR scenario. As shown in <FIG>, an example NR scenario may include an NR core network <NUM>. The NR scenario may further include a new radio access network <NUM>, and the NR core network <NUM> interacts with the new radio access network <NUM> through an interface. In the NR scenario, a function entity configured to implement the communication method in an embodiment of this application may be a CU, a DU, and/or a terminal device (for example, UE). Specifically, a terminal device <NUM> in this embodiment of this application may include a terminal device connected to a base station of the new radio access network <NUM>, for example, UE <NUM> shown in <FIG>. The UE <NUM> is connected to an access network base station <NUM> through a radio link. The access network base station <NUM> may be a base station in the new radio access network <NUM>. The terminal device <NUM> in this embodiment of this application may further include UE connected to a relay station, for example, UE <NUM> shown in <FIG>. The UE <NUM> is connected to a relay station <NUM>, and the relay station <NUM> is connected to the access network base station <NUM> through a relay link. The network device <NUM> shown in <FIG> may be the access network base station <NUM> in the new radio access network <NUM> shown in <FIG>, or may be the relay station <NUM> connected to the access network base station <NUM> shown in <FIG>. The access network base station <NUM> is used as an example. A CU and/or a DU in this application may be used as components/a component of the access network base station <NUM>. Alternatively, the CU and/or the DU may be communication apparatuses/a communication apparatus independent of the access network base station <NUM>. The CU and/or the DU may communicate with the UE <NUM> through the access network base station <NUM>, to implement the method provided in this embodiment of this application. Similarly, the CU and/or the DU may be used as components/a component of the relay station <NUM>, or independent of the relay station <NUM>.

With reference to <FIG>, the following describes a communication method provided in an embodiment of this application by using the wireless communication system shown in <FIG> as an example. The method may include the following steps.

Step S101: ADU <NUM> determines not to start an RLC polling mechanism when sending an RRC message to a terminal device <NUM>.

The RRC message is sent by using a first signaling bearer, and the first signaling bearer may be sent in an RLC acknowledged mode (acknowledged mode, AM).

Step S102: When sending the RRC message to the terminal device <NUM>, the DU <NUM> sets a polling bit in a header of an RLC protocol data unit (protocol data unit, PDU) carrying the RRC message to be in an inactive state.

Specifically, during implementation of step S <NUM>, that the polling bit in the header of the RLC PDU is set to be in the inactive state may mean that a polling bit value of the header of the RLC PDU is set to <NUM>.

In a conventional technology, when the RRC message is sent by using an RLC AM signaling bearer, a polling bit of a last RLC PDU carrying the RRC message is set to be in an active state. As a result, a terminal needs to feed back a status report of an RLC layer. According to the foregoing method, after receiving the RRC message, a terminal device may determine, based on the polling bit of the RLC PDU carrying the RRC message, that an RLC status report does not need to be fed back to the DU, and the terminal device does not need to perform random access to obtain an uplink grant for sending the RLC status report, thereby saving RACH resources.

In a possible implementation, the DU <NUM> may determine, based on the RRC message, not to start the RLC polling mechanism when sending the RRC message to the terminal device <NUM>. During implementation, if the RRC message is the first RRC message sent by the DU <NUM> to the terminal device <NUM> through a first signaling channel, the DU <NUM> determines not to start the RLC polling mechanism when sending the RRC message to the terminal device <NUM>. The first signaling channel is sent in the RLC AM mode. Further, the DU may determine, based on that the RRC message is the first RRC message after a message <NUM> is received, not to start the RLC polling mechanism when sending the RRC message to the terminal device <NUM>.

As shown in <FIG>, signaling channels SRB <NUM>, SRB <NUM>, and SRB <NUM> are maintained between a DU <NUM> and a terminal device <NUM>. If the DU <NUM> determines that an RRC message needs to be sent to the terminal device <NUM>, and the RRC message is the first RRC message sent through the SRB <NUM>, the DU <NUM> determines not to start an RLC polling mechanism when sending the RRC message through the SRB <NUM>. In addition, the DU <NUM> may further determine not to start the RLC polling mechanism when sending the first RRC message through the SRB <NUM>. In the foregoing solution, after the signaling channel between the DU <NUM> and the terminal device <NUM> is resumed through an RRC reestablishment process, the DU <NUM> may not start the RLC polling mechanism when sending the first RRC message through the signaling channel. Therefore, the terminal device <NUM> can be prevented from requesting an uplink grant through random access after receiving the RRC message, to save random access channel resources.

In another possible implementation, the DU <NUM> may further determine, based on an indication of a CU <NUM>, not to start the RLC polling mechanism when sending the RRC message to the terminal device <NUM>.

During implementation, the CU <NUM> may generate first information, and the first information may be used to indicate the DU <NUM> not to start the RLC polling mechanism when the DU <NUM> sends the RRC message to the terminal device <NUM>. The CU <NUM> may include the first message in a downlink RRC transmission (down link RRC message transfer) message or a terminal context setup request (UE context setup request) message that is sent to the DU <NUM>. The CU <NUM> may further send, through a same message, the RRC message that needs to be sent to the terminal device <NUM> and first information specific to the RRC message to the DU <NUM>. For example, the CU <NUM> sends, through a downlink RRC transmission message, the RRC message that needs to be sent to the terminal device <NUM> and the first information specific to the RRC message to the DU <NUM>. Alternatively, the CU <NUM> sends, through a terminal context setup request message, the RRC message that needs to be sent to the terminal device <NUM> and the first information specific to the RRC message to the DU <NUM>.

The first information may be specifically used to indicate the DU <NUM> to set, when the DU <NUM> sends the RRC message to the terminal device <NUM>, a polling bit in a header of an RLC PDU carrying the RRC message to be in an inactive state. Alternatively, the first information may be specifically used to indicate the DU <NUM> not to trigger polling when the DU <NUM> sends the RRC message. A form of the first information is not specifically limited in this application, and the first information may be a specific field and/or a value of a specific bit. Specifically, for example, that the polling bit in the header of the RLC PDU is set to be in the inactive state means that a polling bit value of the header of the RLC PDU is set to <NUM>. After receiving the first information, the DU <NUM> may determine not to start the RLC polling mechanism when sending the RRC message to the terminal device <NUM>. Therefore, when sending the RRC message, the DU <NUM> may set the polling bit of the RLC PDU carrying the RRC message to be in the inactive state. For example, the polling bit is in an active state when the polling bit is set to <NUM>. After receiving the first information, the DU <NUM> may set the polling bit of the RLC PDU carrying the RRC message to <NUM> when sending the RRC message. Therefore, the terminal device <NUM> may determine, based on the polling bit, that an RLC status report does not need to be fed back to the DU <NUM>, and the terminal device <NUM> does not need to initiate random access to request an uplink grant for the RLC status report.

As shown in <FIG>, still using the wireless communication system shown in <FIG> as an example, an RRC message sending method provided in an embodiment of this application includes the following steps.

S201: A CU <NUM> generates an RRC message and first information. The RRC message may be an RRC reestablishment message. Alternatively, the RRC message may be an RRC reestablishment message and an RRC reconfiguration message. Alternatively, the RRC message may be an RRC resume message. The first information is used to indicate a DU <NUM> not to start an RLC polling mechanism when the DU <NUM> sends the RRC message to a terminal device <NUM>.

S202: The CU <NUM> sends a first message to the DU <NUM>, where the first message carries the RRC message and the first information. The first message may be a downlink RRC transmission message. Alternatively, the first message may be a terminal context setup request message.

S203: The DU <NUM> receives the first message, and determines, based on the first information in the first message, not to start the RLC polling mechanism when sending the RRC message.

S204: The DU <NUM> sends the RRC message to the terminal device <NUM>, and sets a polling bit in a header of an RLC PDU carrying the RRC message to be in an inactive state. If the polling bit is <NUM>, it indicates that the polling bit is in an active state. In this case, the DU <NUM> may set the polling bit to <NUM>. The DU <NUM> may further indicate an SR resource when sending the RRC message to the terminal device <NUM>, where the SR resource may be used by the terminal device <NUM> to request an uplink grant. The DU <NUM> may obtain the SR resource from the CU <NUM> or a network device to which the DU <NUM> belongs.

S205: The terminal device <NUM> receives the RRC message. Because the polling bit in the header of the RLC PDU carrying the RRC message is set to be in the inactive state, the terminal device <NUM> does not send an RLC status report to the DU <NUM>. Then, the terminal device <NUM> may send an RRC reestablishment complete (RRC reestablishment complete) message or an RRC reconfiguration complete (RRC reconfiguration complete) message to the DU <NUM> based on the RRC message. The terminal device <NUM> may further request an uplink grant based on the SR resource indicated by the DU <NUM>.

As shown in <FIG>, still using the wireless communication system shown in <FIG> as an example, another RRC message sending method provided in an embodiment of this application includes the following steps.

S301: A terminal device <NUM> sends a preamble sequence (random access preamble) to a DU <NUM>. The preamble sequence is sent through a random access channel, and is used to request to initiate a random access procedure.

S302: After receiving the preamble sequence, the DU <NUM> sends a random access response (random access response) message to the terminal device <NUM>. The random access response message may carry uplink grant information, and the information may be used to indicate an uplink transmission resource allocated to the terminal device <NUM>. For example, the uplink grant information may include a preamble sequence number, timing adjustment information, location information of the uplink transmission resource allocated to the terminal device <NUM>, and a temporary cell radio network temporary identifier (temporary cell radio network temporary identifier, TC-RNTI) temporarily allocated to the terminal device <NUM>.

S303: The terminal device <NUM> sends an RRC reestablishment request to the DU <NUM> based on the uplink transmission resource indicated by the DU <NUM>.

S304: After receiving the RRC reestablishment request, the DU <NUM> sends the RRC reestablishment request to a CU <NUM>. The DU <NUM> may send the RRC reestablishment request to the CU <NUM> through an initial uplink RRC transmission (initial uplink RRC message transfer) message.

In addition, if preamble sequences sent by a plurality of terminal devices to the DU <NUM> in S301 are the same, the plurality of terminal devices simultaneously send RRC reestablishment requests in the step shown in S303, but the DU <NUM> can receive only one RRC reestablishment request based on the preamble sequence. In this case, the DU <NUM> may further intercept the first X bits of received uplink data, and schedule, by using the TC-RNTI, data of X bits to the terminal devices that send the RRC reestablishment requests. If the data of the X bits received by a terminal device is the same as data of the first X bits of the sent RRC reestablishment request, it indicates that the terminal device is a terminal device that successfully performs access, and other terminal devices fail to perform access.

S305: After receiving the RRC reestablishment request, the CU <NUM> sends a terminal context setup request message to the DU <NUM>, to request the DU <NUM> to set up a context of the terminal device <NUM>.

S306: The DU <NUM> sends a terminal context setup response (UE context setup response) message to the CU <NUM> based on the terminal context setup request, to indicate a context setup result of the terminal device <NUM>.

S307: After receiving the terminal context setup response message, the CU <NUM> generates an RRC message and first information. The RRC message may be an RRC reestablishment message. Alternatively, the RRC message may include an RRC reestablishment message and an RRC reconfiguration message. Alternatively, the RRC message may be an RRC resume message. The first information may indicate the DU <NUM> not to start an RLC polling mechanism when the DU <NUM> sends the RRC message. The CU <NUM> may include the RRC message and/or a first message in a same downlink RRC transmission message or a same terminal context setup request message, and send the RRC message and/or the first message to the DU <NUM>. In addition, the CU <NUM> may separately send the RRC message and/or the first message to the DU <NUM> through a plurality of messages. For example, the RRC message includes the RRC reestablishment message and the RRC reconfiguration message. The CU <NUM> may include the RRC reestablishment message and the RRC reconfiguration message in a plurality of downlink RRC transmission messages, and separately send the plurality of downlink RRC transmission messages to the DU <NUM>.

S308: The CU <NUM> sends the first message to the DU <NUM>, where the first message may carry the RRC message and the first information.

S309: After receiving the first message, the DU <NUM> determines, based on the first information, not to start the RLC polling mechanism when sending the RRC message.

S310: The DU <NUM> sends the RRC message to the terminal device <NUM>, and sets a polling bit in a header of an RLC PDU carrying the RRC message to be in an inactive state. If the polling bit is <NUM>, it indicates that the polling bit is in an active state. In this case, the DU <NUM> may set the polling bit to <NUM>. The DU <NUM> may further indicate an SR resource when sending the RRC message to the terminal device <NUM>, where the SR resource may be used by the terminal device <NUM> to request an uplink grant.

S311: The terminal device <NUM> receives the RRC message. Because the polling bit in the header of the RLC PDU carrying the RRC message is set to be in the inactive state, the terminal device <NUM> does not send an RLC status report to the DU <NUM>. Then, the terminal device <NUM> may send an RRC reestablishment complete message or an RRC reconfiguration complete message to the DU <NUM> based on the RRC message. The terminal device <NUM> may further request an uplink grant based on the SR resource indicated by the DU <NUM>.

As shown in <FIG>, an embodiment of this application further provides a feedback information sending method. The method may be applied to the communication system shown in <FIG>. The method may include the following steps.

S401: A terminal device <NUM> receives an RRC message and a resource indication that are sent by a network device <NUM>, where a polling bit in a header of an RLC PDU carrying the RRC message is set to be in an active state, and the resource indication is used to indicate a first uplink transmission resource.

S402: The terminal device <NUM> sends an RLC status report to the network device <NUM> based on a second uplink transmission resource, where the second uplink transmission resource is a transmission resource that the terminal device <NUM> requests, based on the first uplink transmission resource, the network device <NUM> to allocate.

According to the foregoing method, after receiving the RRC message, the terminal device <NUM> no longer needs to obtain an uplink transmission resource through a random access procedure to send the RLC status report to the network device <NUM> based on the uplink transmission resource. Therefore, a quantity of times of random access performed in an RRC reestablishment process can be reduced, thereby saving random access channel resources.

It should be understood that the RRC message herein may include an RRC reestablishment message. Alternatively, the RRC message may include an RRC reestablishment message and an RRC reconfiguration message. Alternatively, the RRC message may be an RRC resume message.

In a possible implementation, if the RRC message in the step shown in S401 is the first RRC message transmitted by the network device <NUM> through a signaling channel after the signaling channel is resumed, the terminal device <NUM> may trigger sending of the RLC status report after preset duration (for example, <NUM>) from a time point at which the terminal device <NUM> receives the RRC message. In this solution, after determining that the polling bit in the header of the RLC PDU carrying the RRC message is set to be in the active state, the terminal device <NUM> may determine that the RLC status report needs to be fed back to the network device <NUM>. After the preset duration, the terminal device <NUM> triggers the sending of the RLC status report, and the terminal device <NUM> may continue to parse the resource indication by using the preset duration, so that the terminal device <NUM> may learn of the first uplink transmission resource indicated by using the resource indication. Therefore, after triggering the sending of the RLC status report, the terminal device <NUM> may request, from the network device <NUM> based on the first uplink transmission resource, the second uplink transmission resource used to transmit the RLC status report, without initiating a random access procedure.

In another possible implementation, after determining that the RLC status report needs to be fed back to the network device <NUM>, the terminal device <NUM> may trigger initiating of the random access procedure to the network device <NUM> to request to obtain an uplink transmission resource, but before the terminal device <NUM> obtains the uplink transmission resource allocated by the network device <NUM>, if the terminal device <NUM> obtains the first uplink transmission resource through parsing, the terminal device <NUM> stops the random access procedure, and requests, from the network device <NUM> based on the first uplink transmission resource, the second uplink transmission resource used to transmit the RLC status report. Then, the terminal device <NUM> may send the RLC status report based on the second uplink transmission resource allocated by the network device <NUM>.

In a possible implementation, the foregoing steps performed by the network device <NUM> may also be performed by the DU <NUM> shown in <FIG>. When the foregoing steps performed by the network device <NUM> are performed by the DU <NUM>, the resource indication may be obtained by the DU <NUM> from a CU <NUM> or a network device to which the DU <NUM> belongs.

In the foregoing embodiments provided in this application, the methods provided in the embodiments of this application are separately described from perspectives of processing actions performed by the CU, the DU, the network device, and the terminal device, and interaction between the CU, the DU, and the terminal device. To implement functions in the methods provided in the embodiments of this application, the CU, the DU, and the terminal device may include a hardware structure and/or a software module, and implement the functions in a form of the hardware structure, the software module, or a combination of the hardware structure and the software module. Whether a specific function in the foregoing functions is performed by the hardware structure, the software module, or the combination of the hardware structure and the software module depends on particular applications and design constraints of the technical solutions.

<FIG> is a schematic structural diagram of a communication apparatus <NUM>. The communication apparatus <NUM> may be a CU, and can implement a function of the CU in the methods provided in the embodiments of this application. The communication apparatus <NUM> may alternatively be an apparatus that can support the CU in implementing a function of the CU in the methods provided in the embodiments of this application. The communication apparatus <NUM> may be a hardware structure, a software module, or a combination of a hardware structure and a software module. The communication apparatus <NUM> may be implemented by a chip system. In this embodiment of this application, the chip system may include a chip, or may include a chip and another discrete component.

The communication apparatus <NUM> may include a processing module <NUM> and a communication module <NUM>.

The processing module <NUM> may be configured to perform step S201 in the embodiment shown in <FIG>, and/or configured to support another process of the technology described in this specification. The communication module <NUM> is configured to perform communication between the communication apparatus <NUM> and another module (including receiving information and data sent by the another module, and sending information and data to the another module), and may be a circuit, a component, an interface, a bus, a software module, a transceiver, or any other apparatus that can implement communication.

The communication module <NUM> may be configured to perform step S202 in the embodiment shown in <FIG>, or configured to perform steps S301, S303, and S311 in the embodiment shown in <FIG>, and/or configured to support another process of the technology described in this specification.

All related content of the steps in the foregoing method embodiments may be cited in function descriptions of corresponding functional modules.

<FIG> is a schematic structural diagram of a communication apparatus <NUM>. The communication apparatus <NUM> may be a DU, and can implement a function of the DU in the methods provided in the embodiments of this application. The communication apparatus <NUM> may alternatively be an apparatus that can support the DU in implementing a function of the DU in the methods provided in the embodiments of this application. The communication apparatus <NUM> may be a hardware structure, a software module, or a combination of a hardware structure and a software module. The communication apparatus <NUM> may be implemented by a chip system. In this embodiment of this application, the chip system may include a chip, or may include a chip and another discrete component.

The processing module <NUM> may be configured to perform step S101 in the embodiment shown in <FIG>, or configured to perform step S203 in the embodiment shown in <FIG>, or configured to perform step S309 in the embodiment shown in <FIG>, and/or configured to support another process of the technology described in this specification.

The communication module <NUM> may be configured to perform step S102 in the embodiment shown in <FIG>, or configured to perform step S204 in the embodiment shown in <FIG>, or configured to perform steps S302, S304, S306, and S310 in the embodiment shown in <FIG>, and/or configured to support another process of the technology described in this specification. The communication module <NUM> is configured to perform communication between the communication apparatus <NUM> and another module (including receiving information and data sent by the another module, and sending information and data to the another module), and may be a circuit, a component, an interface, a bus, a software module, a transceiver, or any other apparatus that can implement communication.

In the embodiments of this application, division into modules is an example, and is merely logical function division. During actual implementation, there may be another division manner. In addition, functional modules in the embodiments of this application may be integrated into one processor, or each of the modules may exist alone physically, or two or more modules may be integrated into one module. The integrated module may be implemented in a form of hardware, or may be implemented in a form of a software functional module.

In addition, <FIG> is a schematic structural diagram of a communication apparatus <NUM>. The communication apparatus <NUM> may be a network device, and can implement a function of the network device in the methods provided in the embodiments of this application. The communication apparatus <NUM> may alternatively be an apparatus that can support the network device in implementing a function of the network device in the methods provided in the embodiments of this application. The communication apparatus <NUM> may be a hardware structure, a software module, or a combination of a hardware structure and a software module. The communication apparatus <NUM> may be implemented by a chip system. In this embodiment of this application, the chip system may include a chip, or may include a chip and another discrete component.

The processing module <NUM> may be configured to generate an RRC message and a resource indication in step S401 in the embodiment shown in <FIG>, and/or configured to support another process of the technology described in this specification.

The communication module <NUM> may be configured to perform step S401 in the embodiment shown in <FIG>, and/or configured to support another process of the technology described in this specification. The communication module <NUM> is configured to perform communication between the communication apparatus <NUM> and another module (including receiving information and data sent by the another module, and sending information and data to the another module), and may be a circuit, a component, an interface, a bus, a software module, a transceiver, or any other apparatus that can implement communication.

<FIG> is a schematic structural diagram of a communication apparatus <NUM>. The communication apparatus <NUM> may be a terminal device, and can implement a function of the terminal device in the methods provided in the embodiments of this application. The communication apparatus <NUM> may alternatively be an apparatus that can support the terminal device in implementing a function of the terminal device in the methods provided in the embodiments of this application. The communication apparatus <NUM> may be a hardware structure, a software module, or a combination of a hardware structure and a software module. The communication apparatus <NUM> may be implemented by a chip system. In this embodiment of this application, the chip system may include a chip, or may include a chip and another discrete component.

The processing module <NUM> may be configured to determine, based on an RLC PDU sent by a DU, not to send an RLC status report to the DU, or configured to determine, based on an RLC PDU sent by a DU or a network device, to send an RLC status report to the DU or the network device on a control channel or a data channel, and/or configured to support another process of the technology described in this specification.

The communication module <NUM> may be configured to perform step S402 in the embodiment shown in <FIG>, and/or configured to support another process of the technology described in this specification. The communication module <NUM> is configured to perform communication between the communication apparatus <NUM> and another module (including receiving information and data sent by the another module, and sending information and data to the another module), and may be a circuit, a component, an interface, a bus, a software module, a transceiver, or any other apparatus that can implement communication.

<FIG> shows a communication apparatus <NUM> provided in an embodiment of this application. The communication apparatus <NUM> may be the CU in the embodiment shown in <FIG> or <FIG>, and can implement a function of the CU in the methods provided in the embodiments of this application. The communication apparatus <NUM> may alternatively be an apparatus that can support the CU in implementing a function of the CU in the methods provided in the embodiments of this application. The communication apparatus <NUM> may be a chip system. In this embodiment of this application, the chip system may include a chip, or may include a chip and another discrete component.

The communication apparatus <NUM> includes at least one processor <NUM>, configured to implement or support the communication apparatus <NUM> in implementing the function of the CU in the methods provided in the embodiments of this application. For example, the processor <NUM> may generate an RRC message and/or first information. For details, refer to the detailed descriptions in the method examples. The processor <NUM> may have a function of the processing module <NUM> shown in <FIG>, and may perform any step that can be performed by the processing module <NUM>.

The communication apparatus <NUM> may further include at least one memory <NUM>, configured to store program instructions and/or data. Coupling in this embodiment of this application is indirect coupling or a communication connection between apparatuses, units, or modules, may be implemented in an electrical form, a mechanical form, or another form, and is used for information exchange between the apparatuses, the units, or the modules. The processor <NUM> may cooperate with the memory <NUM>. The processor <NUM> may execute the program instructions stored in the memory <NUM>. At least one of the at least one memory may be included in the processor.

The communication apparatus <NUM> may further include a communication interface <NUM>, configured to communicate with another device through a transmission medium, so that an apparatus in the communication apparatus <NUM> can communicate with the another device. For example, the another device may be a DU in this embodiment of this application, and the communication interface <NUM> may be configured to send an RRC message and/or first information to the DU. The processor <NUM> may send and receive data through the communication interface <NUM>. The communication interface <NUM> may have a function of the communication module <NUM> shown in <FIG>, and may perform any step that can be performed by the communication module <NUM>.

A specific connection medium between the communication interface <NUM>, the processor <NUM>, and the memory <NUM> is not limited in this embodiment of this application. In this embodiment of this application, in <FIG>, the memory <NUM>, the processor <NUM>, and the communication interface <NUM> are connected through a bus <NUM>. The bus is represented by a thick line in <FIG>. A connection manner between other components is merely described as an example, and is not limited thereto. The bus may be classified into an address bus, a data bus, a control bus, and the like. For ease of representation, only one thick line is used to represent the bus in <FIG>, but this does not mean that there is only one bus or only one type of bus.

In this embodiment of this application, the processor <NUM> may be a general purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or another programmable logic device, a discrete gate or a transistor logic device, or a discrete hardware component, and may implement or perform the methods, steps, and logical block diagrams disclosed in the embodiments of this application. The general purpose processor may be a microprocessor, any conventional processor, or the like. The steps in the methods disclosed with reference to the embodiments of this application may be directly performed and completed by a hardware processor, or may be performed and completed by using a combination of hardware and software modules in the processor.

In this embodiment of this application, the memory <NUM> may be a non-volatile memory, such as a hard disk drive (hard disk drive, HDD) or a solid-state drive (solid-state drive, SSD), or may be a volatile memory (volatile memory), such as a random access memory (random access memory, RAM). The memory is any other medium that can be used to carry or store expected program code in a form of instructions or a data structure and that can be accessed by a computer. However, this is not limited thereto. The memory in this embodiment of this application may alternatively be a circuit or any other apparatus that can implement a storage function, and is configured to store program instructions and/or data.

<FIG> shows a communication apparatus <NUM> provided an embodiment of this application. The communication apparatus <NUM> may be a DU, and can implement a function of the DU in the methods provided in the embodiments of this application. The communication apparatus <NUM> may alternatively be an apparatus that can support the DU in implementing a function of the DU in the methods provided in the embodiments of this application. The communication apparatus <NUM> may be a chip system. In this embodiment of this application, the chip system may include a chip, or may include a chip and another discrete component.

The communication apparatus <NUM> includes at least one processor <NUM>, configured to implement or support the communication apparatus <NUM> in implementing the function of the DU in the methods provided in the embodiments of this application. For example, the processor <NUM> may determine, based on first information, not to start an RLC polling mechanism when an RRC message is sent. For details, refer to the detailed descriptions in the method examples. The processor <NUM> may have a function of the processing module <NUM> shown in <FIG>, and may perform any step that can be performed by the processing module <NUM>.

The communication apparatus <NUM> may further include a communication interface <NUM>, configured to communicate with another device through a transmission medium, so that an apparatus in the communication apparatus <NUM> can communicate with the another device. For example, the another device may be a CU or a terminal device. The processor <NUM> may send and receive data through the communication interface <NUM>. The communication interface <NUM> may have a function of the communication module <NUM> shown in <FIG>, and may perform any step that can be performed by the communication module <NUM>.

In this embodiment of this application, the memory <NUM> may be a non-volatile memory, such as a hard disk drive or a solid-state drive, or may be a volatile memory, such as a random access memory. The memory is any other medium that can be used to carry or store expected program code in a form of instructions or a data structure and that can be accessed by a computer. However, this is not limited thereto. The memory in this embodiment of this application may alternatively be a circuit or any other apparatus that can implement a storage function, and is configured to store program instructions and/or data.

<FIG> shows a communication apparatus <NUM> provided in an embodiment of this application. The communication apparatus <NUM> may be a network device, and can implement a function of the network device in the methods provided in the embodiments of this application. The communication apparatus <NUM> may alternatively be an apparatus that can support the network device in implementing a function of the network device in the methods provided in the embodiments of this application. The communication apparatus <NUM> may be a chip system. In this embodiment of this application, the chip system may include a chip, or may include a chip and another discrete component.

The communication apparatus <NUM> includes at least one processor <NUM>, configured to implement or support the communication apparatus <NUM> in implementing the function of the network device in the methods provided in the embodiments of this application. For example, the processor <NUM> may generate an RRC message. For details, refer to the detailed descriptions in the method examples. The processor <NUM> may further have a function of the processing module <NUM> shown in <FIG>, and may perform any step that can be performed by the processing module <NUM>.

The communication apparatus <NUM> may further include a communication interface <NUM>, configured to communicate with another device through a transmission medium, so that an apparatus in the communication apparatus <NUM> can communicate with the another device. For example, the another device may be a terminal device. The processor <NUM> may send and receive data through the communication interface <NUM>. The communication interface <NUM> may have a function of the communication module <NUM> shown in <FIG>, and may perform any step that can be performed by the communication module <NUM>.

<FIG> shows a communication apparatus <NUM> provided in an embodiment of this application. The communication apparatus <NUM> may be a terminal device, and can implement a function of the terminal device in the methods provided in the embodiments of this application. The communication apparatus <NUM> may alternatively be an apparatus that can support the terminal device in implementing a function of the terminal device in the methods provided in the embodiments of this application. The communication apparatus <NUM> may be a chip system. In this embodiment of this application, the chip system may include a chip, or may include a chip and another discrete component.

The communication apparatus <NUM> includes at least one processor <NUM>, configured to implement or support the communication apparatus <NUM> in implementing a function of the terminal device in the methods provided in the embodiments of this application. For example, the processor <NUM> may be configured to determine, based on an RLC PDU sent by a DU, not to send an RLC status report to a network device, or configured to determine, based on an RLC PDU sent by a DU or a network device, to send an RLC status report to the DU or the network device on a control channel or a data channel. For details, refer to the detailed descriptions in the method examples. The processor <NUM> may further have a function of the processing module <NUM> shown in <FIG>, and may perform any step that can be performed by the processing module <NUM>.

An embodiment of this application further provides a communication apparatus, and the communication apparatus may be a terminal device or a circuit. The communication apparatus may be configured to perform an action performed by the terminal device in the foregoing method embodiments.

When the communication apparatus is a terminal device, <FIG> is a simplified schematic structural diagram of the terminal device. For ease of understanding and illustration, an example in which the terminal device is a mobile phone is used in <FIG>. As shown in <FIG>, the terminal device includes a processor, a memory, a radio frequency circuit, an antenna, and an input/output apparatus. The processor is mainly configured to: process a communication protocol and communication data, control the terminal device, execute a software program, process data of the software program, and the like. The memory is mainly configured to store the software program and the data. The radio frequency circuit is mainly configured to: perform conversion between a baseband signal and a radio frequency signal, and process the radio frequency signal. The antenna is mainly configured to send and receive a radio frequency signal in a form of an electromagnetic wave. The input/output apparatus such as a touchscreen, a display, or a keyboard is mainly configured to: receive data entered by a user and output data to the user. It should be noted that some types of terminal devices may have no input/output apparatus.

When data needs to be sent, after performing baseband processing on the to-be-sent data, the processor outputs a baseband signal to the radio frequency circuit. After performing radio frequency processing on the baseband signal, the radio frequency circuit sends a radio frequency signal to the outside in a form of an electromagnetic wave through the antenna. When data is sent to the terminal device, the radio frequency circuit receives a radio frequency signal through the antenna, converts the radio frequency signal into a baseband signal, and outputs the baseband signal to the processor. The processor converts the baseband signal into data, and processes the data. For ease of description, <FIG> shows only one memory and one processor. In an actual terminal device product, there may be one or more processors and one or more memories. The memory may also be referred to as a storage medium, a storage device, or the like. The memory may be disposed independent of the processor, or may be integrated with the processor. This is not limited in this embodiment of this application.

In this embodiment of this application, the antenna and the radio frequency circuit that have sending and receiving functions may be considered as a transceiver unit of the terminal device, and the processor that has a processing function may be considered as a processing unit of the terminal device. As shown in <FIG>, the terminal device includes a transceiver unit <NUM> and a processing unit <NUM>. The transceiver unit may also be referred to as a transceiver, a transceiver machine, a transceiver apparatus, or the like. The processing unit may also be referred to as a processor, a processing board, a processing module, a processing apparatus, or the like. Optionally, a component for implementing a receiving function in the transceiver unit <NUM> may be considered as a receiving unit, and a component for implementing a sending function in the transceiver unit <NUM> may be considered as a sending unit. In other words, the transceiver unit <NUM> includes the receiving unit and the sending unit. The transceiver unit may also be sometimes referred to as a transceiver machine, a transceiver, a transceiver circuit, or the like. The receiving unit may also be sometimes referred to as a receiver machine, a receiver, a receiver circuit, or the like. The sending unit may also be sometimes referred to as a transmitter machine, a transmitter, a transmitter circuit, or the like.

It should be understood that the transceiver unit <NUM> is configured to perform a sending operation and a receiving operation on the terminal device side in the foregoing method embodiments, and the processing unit <NUM> is configured to perform an operation other than the sending operation and the receiving operation of the terminal device in the foregoing method embodiments.

For example, in an implementation, the transceiver unit <NUM> is configured to perform the RRC message receiving operation on the terminal device side in <FIG>, and/or the transceiver unit <NUM> is further configured to perform another sending step and receiving step on the terminal device side in the embodiments of this application. The processing unit <NUM> is configured to determine, based on a polling bit in a header of an RLC PDU carrying an RRC message, not to send an RLC status report to a DU, and/or the processing unit <NUM> is further configured to perform another processing step on the terminal device side in the embodiments of this application.

For another example, in another implementation, the transceiver unit <NUM> is configured to perform the RRC message receiving operation on the terminal device side in <FIG>, and/or the transceiver unit <NUM> is further configured to perform another sending step and receiving step on the terminal device side in the embodiments of this application. The processing unit <NUM> is configured to determine, based on a polling bit in a header of an RLC PDU carrying an RRC message, not to send an RLC status report to a DU, and/or the processing unit <NUM> is further configured to perform another processing step on the terminal device side in the embodiments of this application.

For still another example, in still another implementation, the transceiver unit <NUM> is configured to receive the random access response message in steps S301, S303, S310, and step S302 in <FIG>, and/orthe transceiver unit <NUM> is further configured to perform another sending step and receiving step on the terminal device side in the embodiments of this application. The processing unit <NUM> is configured to determine, based on a polling bit in a header of an RLC PDU carrying an RRC message, not to send an RLC status report to a DU, and/or the processing unit <NUM> is further configured to perform another processing step on the terminal device side in the embodiments of this application.

For still another example, in still another implementation, the transceiver unit <NUM> is configured to: perform step S402 and receive the RRC message and the resource indication in step S401 in <FIG>, and/or the transceiver unit <NUM> is further configured to perform another sending step and receiving step on the terminal device side in the embodiments of this application. The processing unit <NUM> is configured to determine to send an RLC status report to a network device on a control channel or a data channel, and/or the processing unit <NUM> is further configured to perform another processing step on the terminal device side in the embodiments of this application.

When the communication apparatus is a chip, the chip includes a transceiver unit and a processing unit. The transceiver unit may be an input/output circuit or a communication interface. The processing unit is a processor, a microprocessor, or an integrated circuit integrated on the chip.

When the communication apparatus in this embodiment is a terminal device, refer to a device shown in <FIG>. In an example, the device can complete a function similar to a function of the processor in <FIG>. In <FIG>, the device includes a processor <NUM>, a data sending processor <NUM>, and a data receiving processor <NUM>. The processing unit <NUM> in the foregoing embodiment may be the processor <NUM> in <FIG>, and completes a corresponding function. The transceiver unit <NUM> in the foregoing embodiment may be the data sending processor <NUM> and/or the data receiving processor <NUM> in <FIG>. Although <FIG> shows a channel encoder and a channel decoder, it may be understood that these modules are merely examples, and do not constitute a limitation on this embodiment.

<FIG> shows another form of this embodiment. A processing apparatus <NUM> includes modules such as a modulation subsystem, a central processing subsystem, and a peripheral subsystem. A communication apparatus in this embodiment may be used as the modulation subsystem in the processing apparatus <NUM>. Specifically, the modulation subsystem may include a processor <NUM> and an interface <NUM>. The processor <NUM> completes a function of the processing unit <NUM>, and the interface <NUM> completes a function of the transceiver unit <NUM>. In another variation, the modulation subsystem includes a memory <NUM>, a processor <NUM>, and a program that is stored in the memory <NUM> and that can run on the processor. When executing the program, the processor <NUM> implements the method on the terminal device side in the foregoing method embodiments. It should be noted that, the memory <NUM> may be non-volatile or volatile, the memory <NUM> may be located in the modulation subsystem or in the processing apparatus <NUM>, provided that the memory <NUM> can be connected to the processor <NUM>.

In another form of this embodiment, a computer-readable storage medium is provided. The computer-readable storage medium stores instructions. When the instructions are executed, the method on the terminal device side in the foregoing method embodiments is performed.

In another form of this embodiment, a computer program product that includes instructions is provided. When the instructions are executed, the method on the terminal device side in the foregoing method embodiments is performed.

When the communication apparatus in this embodiment is a network device, the network device may be that shown in <FIG>. A communication apparatus <NUM> includes one or more radio frequency units, such as a remote radio unit (remote radio unit, RRU) <NUM> and one or more baseband units (baseband unit, BBU) (which may also be referred to as a digital unit (digital unit, DU)) <NUM>. The RRU <NUM> may be referred to as a communication module, and corresponds to the communication module <NUM> in <FIG>. The communication module <NUM> may also be referred to as a transceiver machine, a transceiver circuit, a transceiver, or the like, and may include at least one antenna and the remote radio unit <NUM>. The RRU <NUM> is mainly configured to: send and receive a radio frequency signal, and perform conversion between the radio frequency signal and a baseband signal. For example, the RRU <NUM> is configured to send a resource indication to a terminal device. The BBU <NUM> is mainly configured to: perform baseband processing, control a base station, and the like. The RRU <NUM> and the BBU <NUM> may be physically disposed together, or may be physically separated, namely, a distributed base station.

The BBU <NUM> is a control center of the base station, and may also be referred to as a processing module. The BBU <NUM> may correspond to the processing module <NUM> in <FIG>, and may be configured to complete a baseband processing function such as channel coding, multiplexing, modulation, or spreading. For example, the BBU <NUM> may be configured to control the network device to perform an operation procedure related to the network device in the foregoing method embodiments, for example, generate an RRC message and first information.

In an example, the BBU <NUM> may include one or more boards, and a plurality of boards may jointly support a radio access network (for example, an LTE network) having a single access standard, or may separately support radio access networks (for example, an LTE network, a <NUM> network, or another network) having different access standards. The BBU <NUM> further includes a memory <NUM> and a processor <NUM>. The memory <NUM> is configured to store necessary instructions and data. The processor <NUM> is configured to control the network device to perform a necessary action, for example, configured to control the network device to perform an operation procedure performed by the CU, the DU and/or the network device in the foregoing method embodiments. The memory <NUM> and the processor <NUM> may serve one or more boards. In other words, a memory and a processor may be independently disposed on each board. Alternatively, a plurality of boards may share a same memory and a same processor. In addition, a necessary circuit may be further disposed on each board.

In another example, a communication apparatus may further have a structure of a CU <NUM> or a DU <NUM> shown in <FIG>. As shown in <FIG>, a method provided in this embodiment of this application may include the CU <NUM>, the DU <NUM>, and an antenna unit <NUM>, and the antenna unit herein may be an active antenna unit (active antenna unit, AAU) or an RRU. For a structure of the antenna unit <NUM>, refer to a structure of the RRU <NUM> shown in <FIG>. The CU <NUM> may be configured to implement a non-real-time wireless high-layer protocol stack function, and may also be configured to support deployment of some core networks and deployment of an edge application service. The CU <NUM> may include a PDCP layer and an RRC layer. The DU <NUM> may be configured to process a physical layer function and a layer (layer) <NUM> function with a real-time requirement. Some physical layer functions of a network device may also be transferred to the antenna unit <NUM> for implementation. The DU <NUM> may include an RLC layer, a MAC layer, and a PHY layer. The antenna unit <NUM> has a function of the RRU <NUM> shown in <FIG>, and may be further configured to implement the baseband processing function of the BBU <NUM> in the network device shown in <FIG>. Some or all components of the CU <NUM>, the DU <NUM>, or the antenna unit <NUM> may be used as a part of the network device, or may be used as a communication apparatus independent of the network device. The CU <NUM>, the DU <NUM>, and the antenna unit <NUM> may be physically disposed together, or may be physically disposed separately.

As shown in <FIG>, the CU <NUM> and the DU <NUM> may separately include one or more boards, and the one or more boards may jointly support the CU <NUM>, the DU <NUM>, and a radio access network (for example, an LTE network) having a single access standard, or may separately support the CU <NUM>, the DU <NUM>, and radio access networks (for example, an LTE network, a <NUM> network, or another network) having different access standards.

The CU <NUM> may include a memory <NUM> and a processor <NUM>. The memory <NUM> is configured to store necessary instructions and data. The processor <NUM> is configured to control the CU <NUM> to perform a necessary action, for example, configured to control the CU <NUM> to perform an operation procedure performed by the CU in the foregoing method embodiments. The memory <NUM> and the processor <NUM> may serve one or more boards. In other words, a memory and a processor may be independently disposed on each board. Alternatively, a plurality of boards may share a same memory and a same processor. In addition, a necessary circuit may be further disposed on each board. The CU <NUM> may further have a structure shown in <FIG> or <FIG>. In other words, the CU <NUM> may have a function of the communication apparatus shown in <FIG> or <FIG>. Therefore, the CU <NUM> may perform a step that can be performed by the communication apparatus shown in <FIG> or <FIG>. The processor <NUM> may be specifically configured to perform a function performed by the processor <NUM> shown in <FIG>.

The DU <NUM> may include a memory <NUM> and a processor <NUM>. The memory <NUM> is configured to store necessary instructions and data. The processor <NUM> is configured to control the DU <NUM> to perform a necessary action, for example, configured to control the DU <NUM> to perform an operation procedure performed by the DU in the foregoing method embodiments. The memory <NUM> and the processor <NUM> may serve one or more boards. In other words, a memory and a processor may be independently disposed on each board. Alternatively, a plurality of boards may share a same memory and a same processor. In addition, a necessary circuit may be further disposed on each board. The DU <NUM> may further have a structure shown in <FIG> or <FIG>. In other words, the DU <NUM> may have a function of the communication apparatus shown in <FIG> or <FIG>. Therefore, the DU <NUM> may perform a step that can be performed by the communication apparatus shown in <FIG> or <FIG>. The processor <NUM> may be specifically configured to perform a function performed by the processor <NUM> shown in <FIG>.

The CU <NUM>, the DU <NUM>, and the antenna unit <NUM> shown in <FIG> may form an NR base station.

It should be understood that, the processor mentioned in the embodiments of the present invention may be a central processing unit (Central Processing Unit, CPU), or may be another general purpose processor, a digital signal processor (Digital Signal Processor, DSP), an application-specific integrated circuit (Application Specific Integrated Circuit, ASIC), a field programmable gate array (Field Programmable Gate Array, FPGA) or another programmable logic device, a discrete gate or a transistor logic device, a discrete hardware component, or the like. The general purpose processor may be a microprocessor, or the processor may be any conventional processor, or the like.

It should be further understood that the memory mentioned in the embodiments of the present invention may be a volatile memory or a non-volatile memory, or may include a volatile memory and a non-volatile memory. The non-volatile memory may be a read-only memory (Read-Only Memory, ROM), a programmable read-only memory (Programmable ROM, PROM), an erasable programmable read-only memory (Erasable PROM, EPROM), an electrically erasable programmable read-only memory (Electrically EPROM, EEPROM), or a flash memory. The volatile memory may be a random access memory, used as an external cache. Through example but not limitative description, many forms of RAMs may be used, for example, a static random access memory (Static RAM, SRAM), a dynamic random access memory (Dynamic RAM, DRAM), a synchronous dynamic random access memory (Synchronous DRAM, SDRAM), a double data rate synchronous dynamic random access memory (Double Data Rate SDRAM, DDR SDRAM), an enhanced synchronous dynamic random access memory (Enhanced SDRAM, ESDRAM), a synchlink dynamic random access memory (Synchlink DRAM, SLDRAM), and a direct rambus random access memory (Direct Rambus RAM, DR RAM).

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

It should be noted that the memory described in this specification is intended to include but is not limited to these memories and any memory of another proper type.

It should be further understood that "first", "second", "third", "fourth", and various numbers in this specification are merely distinguished for convenient description, and are not intended to limit the scope of this application.

It should be understood that the term "and/or" in this specification describes only an association relationship between associated objects and represents that three relationships may exist. In addition, the character "/" in this specification usually indicates an "or" relationship between the associated objects.

It should be understood that, in various embodiments of this application, sequence numbers of the foregoing processes do not mean execution sequences. The execution sequences of the processes should be determined based on functions and internal logic of the processes, and should not be construed as any limitation on the implementation processes of the embodiments of the present invention.

A person of ordinary skill in the art may be aware that units and algorithm steps in the examples described with reference to the embodiments disclosed in this specification can be implemented by electronic hardware or a combination of computer software and electronic hardware.

It may be clearly understood by a person skilled in the art that for the purpose of convenient and brief description, for a detailed working process of the described system, apparatus, and unit, refer to a corresponding process in the foregoing method embodiments.

For example, the described apparatus embodiments are merely examples. For example, division into the units is merely logical function division. During actual implementation, there may be another division manner. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections may be implemented through some interfaces. The indirect couplings or communication connections between the apparatuses or units may be implemented in an electrical form, a mechanical form, or another form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, and may be located in one position, or may be distributed on a plurality of network units. Some or all of the units may be selected based on an actual requirement to achieve the objective of the solutions of the embodiments.

Claim 1:
A radio resource control RRC message sending method, comprising:
generating, by a centralized unit CU (<NUM>), first information; and
sending, by the CU (<NUM>), the first information to a distributed unit DU (<NUM>), wherein the first information is used to indicate the DU (<NUM>) not to start a radio link layer control protocol RLC polling mechanism when the DU (<NUM>) sends an RRC message to a terminal apparatus, wherein the first information is specifically used to indicate the DU (<NUM>) to set, when the DU (<NUM>) sends the RRC message to the terminal apparatus, a polling bit in a header of an RLC protocol data unit PDU carrying the RRC message to be in an inactive state; or
the first information is specifically used to indicate the DU (<NUM>) not to trigger polling when the DU (<NUM>) sends the RRC message to the terminal apparatus.