Patent Description:
In a 5th generation (the 5th generation, <NUM>) new radio (new radio, NR) system, a carrier bandwidth may reach <NUM> megahertz (MHz). However, a bandwidth supported by a bandwidth capacity supported by a terminal device is usually less than the carrier bandwidth. The bandwidth capability of the terminal device may be a maximum bandwidth that can be supported by the terminal device, for example, may be <NUM> or <NUM>. To adapt the bandwidth capability of the terminal device, a plurality of bandwidth parts (bandwidth part, BWP) may be configured on one carrier (carrier), and each BWP may include a segment of contiguous resources in frequency domain. In a single-carrier scenario, a network device may activate one BWP on one carrier for the terminal device at a same moment, and may switch the active BWP on the carrier by using downlink control information (downlink control information, DCI) or radio resource control (radio resource control, RRC) signaling.

However, in a carrier aggregation scenario, the foregoing BWP switching mechanism is not compatible.

<CIT> relates to method for signaling bandwidth part (BWP) indicators and radio communication equipment using the same.

Implementations of this application provide communication methods, a terminal device and a network device to optimize a problem of switching an active BWP in a carrier aggregation scenario.

According to a first aspect, a communication method is provided. The communication method includes: A terminal device receives a first command sent by a network device, where the first command carries a first identifier, the first command is used to activate a first BWP indicated by the first identifier, and the first BWP is a BWP on a first component carrier (component carrier, CC); and the terminal device ignores the first command when the terminal device does not support the first BWP and a second BWP in being in an active state at the same time, where the second BWP is a BWP in the active state on a second CC, and the second CC is different from the first CC.

In this aspect, after ignoring the first command, the terminal device may further send a first indication to the network device, where the first indication is used to indicate that the first command does not take effect, or send a negative acknowledgement NACK message for the first command to the network device. The first indication may carry the first identifier.

According to the foregoing method, after receiving the first command, the terminal device does not immediately execute the first command, but further determines whether the terminal device supports the first BWP and the second BWP in being in the active state at the same time. If the terminal device does not support the first BWP and the second BWP in being in the active state at the same time, the terminal device ignores the first command. However, if the terminal device still uses a BWP switching mechanism in a single-carrier scenario, the terminal device immediately executes the first command after receiving the first command. Because the terminal device does not support the first BWP and the second BWP in being in the active state at the same time, an error may occur when the terminal device executes the first command; or after executing the first command, the terminal device cannot correctly transmit data in the first BWP and the second BWP. According to the foregoing method, the terminal device may determine, based on a capability of the terminal device, to ignore an improper command, to optimize a problem of switching an active BWP in a carrier aggregation scenario.

In a possible design, there may be a plurality of first commands, and each first command may correspond to one first CC. In this design, that the terminal device does not support the first BWP and a second BWP in being in an active state at the same time may include: The terminal device does not support a plurality of first BWPs and a plurality of second BWPs in being in the active state at the same time, where the plurality of first BWPs are first BWPs that are indicated by the first identifier and that are respectively carried in the plurality of first commands; and that the terminal device ignores the first command may include: the terminal device ignores the plurality of first BWPs. In other words, if the terminal device receives the plurality of first commands, when the terminal device does not support the plurality of first BWPs and the plurality of second BWPs in being in the active state at the same time, the terminal device ignores all the received first commands. Further, there may be a plurality of second BWPs and a plurality of second CCs. Based on this, that the terminal device does not support the first BWP and a second BWP in being in an active state at the same time may include: The terminal device does not support the plurality of first BWPs and the plurality of second BWPs in being in the active state at the same time.

That the first command corresponds to the first CC may be understood as the first command sent for the first CC. That the second CC is different from the first CC may be understood as that the second CC is a type of CC on which the terminal device does not receive a corresponding first command.

In a possible design, the first command carries a second identifier, and the second identifier is used to identify the first CC. In this way, after receiving the first command, the terminal device may determine, based on the second identifier carried in the first command, that the first command is sent for the first CC. Certainly, if the first command does not carry the second identifier, the terminal device may alternatively determine, according to a rule agreed with the network device, that the first command corresponds to the first CC. For example, the terminal device may agree with the network device that if the first command is sent on the first CC, the terminal device may determine that the first command corresponds to the first CC.

In a possible design, the first command may include a BWP activation command, a BWP switching command, or a secondary cell activation command.

In a second aspect, a corresponding method performed by a network device is provided.

In further aspects, a terminal device and a network device configured to perform the respective methods according to the first and the second aspects are also provided.

It should be understood that the technical solutions in implementations of this application may be used in a <NUM> communications system, a future <NUM> communications system, or the like. This is not limited in the implementations of this application.

A terminal device in the implementations of this application may be a device that provides voice and/or data connectivity for a user, and is also referred to as user equipment (user equipment, UE), a mobile station (mobile station, MS), a mobile terminal (mobile terminal, MT), or the like, for example, a handheld device or a vehicle-mounted device that has a wireless connection function. Currently, some examples of the terminal device are: a mobile phone (mobile phone), a tablet computer, a notebook computer, a palmtop computer, a mobile internet device (mobile internet device, MID), a wearable device, a virtual reality (virtual reality, VR) device, an augmented reality (augmented reality, AR) device, a wireless terminal in industrial control (industrial control), a wireless terminal in self driving (self driving), a wireless terminal in remote medical surgery (remote medical surgery), a wireless terminal in a smart grid (smart grid), a wireless terminal in transportation safety (transportation safety), a wireless terminal in a smart city (smart city), a wireless terminal in a smart home (smart home), or the like.

A network device in the implementations of this application may be a device in a wireless network, for example, a radio access network (radio access network, RAN) node (or device) that connects a terminal device to the wireless network, and may also be referred to as a base station. Currently, some examples of the RAN nodes are: a next generation NodeB (gNB), a transmission reception point (transmission reception point, TRP), an evolved NodeB (evolved NodeB, eNB), a radio network controller (radio network controller, RNC), a NodeB (NodeB, NB), a base station controller (base station controller, BSC), a base transceiver station (base transceiver station, BTS), a home evolved NodeB (for example, a home evolved NodeB or a home NodeB, HNB), a baseband unit (baseband unit, BBU), a wireless fidelity (wireless fidelity, Wi-Fi) access point (access point, AP), or the like. In addition, in a network structure, the RAN may include a centralized unit (centralized unit, CU) node and a distributed unit (distributed unit, DU) node. In this structure, protocol layers of an eNB in a long term evolution (long term evolution, LTE) system are split, where functions of some protocol layers are centrally controlled by the CU, functions of some or all of remaining protocol layers are distributed in the DU, and the CU centrally controls the DU.

A core network (core network, CN) device is provided in the implementations of this application. The CN device corresponds to different devices in different communications systems, for example, corresponds to a serving GPRS support node (serving GPRS support node, SGSN) or a gateway GPRS support node (gateway GPRS support node, GGSN) in a <NUM> system, corresponds to a mobility management entity (mobility management entity, MME) or a serving gateway (serving gateway, S-GW) in a <NUM> system, and in a <NUM> system, corresponds to a core network-related device (for example, an NG-Core) in the <NUM> system.

For ease of understanding this application, some terms in this application are first explained and described.

(<NUM>) A carrier bandwidth is a bandwidth supported by a carrier, and may also be referred to as a system bandwidth, a carrier, or the like. For example, a carrier bandwidth of an NR system may be one of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or the like. (<NUM>) A BWP is a segment of contiguous resources (for example, a group of contiguous RBs in a carrier bandwidth) configured for a terminal device in the carrier bandwidth in an NR system to adapt to a bandwidth capability of the terminal device. A plurality of BWPs may be configured on one carrier. For example, four BWPs may be configured on one carrier. A network device may configure several BWPs for the terminal device. However, only one BWP is in an active state at any moment, and the BWP in the active state is a currently available BWP. In addition, sometimes, the bandwidth part may also be referred to as a carrier bandwidth part (carrier bandwidth part), a subband (subband) bandwidth, a narrowband (narrowband) bandwidth, or another name. The name is not limited in this application. For ease of description, an example in which the name is the BWP is used for description. For example, one BWP includes K (K><NUM>) contiguous subcarriers. Alternatively, one BWP is a frequency domain resource on which N non-overlapping contiguous RBs are located, and a subcarrier spacing (subcarrier spacing, SCS) of the RB may be <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or another value. Alternatively, one BWP is a frequency domain resource on which M non-overlapping contiguous resource block groups (resource block group, RBG) are located, one RBG includes P (P><NUM>) contiguous RBs, and a subcarrier spacing (subcarrier spacing, SCS) of the RB may be <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or another value, for example, an integer multiple of <NUM>. <FIG> show three types of configurations of BWPs in carrier bandwidths according to implementations of this application. <FIG> shows a case in which one BWP is configured in a carrier bandwidth. A network device may first allocate the BWP within a bandwidth capability range of a terminal device to the terminal device, and certainly may further allocate some or all of resources in the BWP to the terminal device for data transmission. The network device may configure different BWPs for the terminal device based on an actual scenario. For example, to reduce power consumption of the terminal device, the network device may allocate the BWP to the terminal device based on a service volume of the terminal device. When the terminal device transmits no service data or transmits only a small amount of service data, a relatively small BWP, for example, a BWP <NUM> shown in <FIG>, may be allocated to the terminal device to receive control information and a small amount of data information. When the terminal device needs to transmit a large amount of service data, a relatively large bandwidth part, for example, a BWP <NUM> shown in <FIG>, may be allocated to the terminal device. For another example, in <NUM>, a plurality of service types and communication scenarios may be supported, and different parameters may be configured for different service types and communication scenarios. The network device may allocate corresponding BWPs to the terminal device based on different service types of the terminal device. As shown in <FIG>, one BWP may correspond to one service type, and to meet a service requirement of the service type, the BWP may be configured with a numerology (numerology) that can meet the service requirement. It can be learned from <FIG> that different BWPs may occupy frequency domain resources that partially overlap. It can be learned from <FIG> that different BWPs may alternatively occupy completely different frequency domain resources and use different numerologies. In the implementations of this application, numerologies corresponding to different BWPs may be the same or may be different. This is not limited in this application. It may be understood that in <FIG>, an example in which only one or two BWPs are configured on one carrier is used for description. In an actual application, a plurality of BWPs may be configured on the carrier. This is not limited in this application. (<NUM>) A numerology is a parameter used in a communications system, for example, may be a series of physical layer parameters in an air interface (air interface). During specific implementation, one BWP may correspond to one numerology. An NR system may support a plurality of numerologies, and the plurality of numerologies can be used interchangeably. The numerology may include one or more of the following parameter information: a subcarrier spacing, information about a cyclic prefix (cyclic prefix, CP), information about a time unit, a bandwidth, or the like. The information about the CP may include a length of the CP and/or a CP type. For example, the CP may be a normal CP (normal CP, NCP) or an extended CP (extended CP, ECP). The time unit is used to indicate a time unit in time domain, and may be, for example, a sampling point, a symbol, a mini-slot (mini-slot), a slot (slot), a subframe (subframe), or a radio frame. The information about the time unit may include a type, a length, a structure, or the like of the time unit. For example, the numerology may include the subcarrier spacing and the CP. Referring to Table <NUM>, Table <NUM> provides a numerology that can be currently supported in the NR system and that is defined by the subcarrier spacing and the CP.

µ is used to determine the subcarrier spacing. For example, when µ=<NUM>, the subcarrier spacing is <NUM>; or when µ=<NUM>, the subcarrier spacing is <NUM>.

The subcarrier spacing is used as an example. If the terminal device supports the subcarrier spacing of <NUM> and the subcarrier spacing of <NUM>, the network device may allocate a BWP with the subcarrier spacing of <NUM> and a BWP with the subcarrier spacing of <NUM> to the terminal device. The terminal device may switch to different BWPs for signal transmission based on different scenarios and service requirements. When the terminal device supports a plurality of BWPs, numerologies corresponding to different BWPs may be the same or may be different.

The subcarrier spacing may be an integer greater than or equal to <NUM>. For example, the subcarrier spacing may be <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or the like. For example, different subcarrier spacings may be integer multiples of <NUM>. It may be understood that the subcarrier spacing may alternatively be designed to be another value. The subcarrier spacing is a value of a spacing between central positions or peak positions of two adjacent subcarriers in frequency domain in an orthogonal frequency division multiplexing (orthogonal frequency division multiplexing, OFDM) system. For example, a subcarrier spacing in an LTE system is <NUM> (kilohertz, kHz), and a subcarrier spacing in an NR system may be <NUM>, <NUM>, <NUM>, <NUM>, or the like.

(<NUM>) Carrier aggregation (carrier aggregation, CA) supports aggregation of a plurality of (for example, two to five) CCs, to implement a relatively high transmission bandwidth, so that uplink and downlink transmission rates can be efficiently improved. The terminal device may determine, based on a capability of the terminal device, a maximum quantity of CCs that can be used at the same time for uplink and downlink transmission. When the terminal device works in a carrier aggregation scenario, a plurality of CCs are configured, and several BWPs may be configured on each CC. Activation and deactivation of BWPs between CCs may be completely independent.

(<NUM>) Activating a BWP means switching the BWP from an inactive state to an active state, or may be understood as switching an unworkable BWP to a workable BWP. Correspondingly, "deactivating" the BWP may also be described as performing deactivation on the BWP, that is, switching the BWP from the active state to the inactive state, or may also be understood as switching a workable BWP to an unworkable BWP.

(<NUM>) An active state may be a workable state. That the BWP is in the active state means that the BWP is in the workable state, for example, a state in which a signal can be sent or received. An inactive state is a concept corresponding to the active state, and may be an unworkable state. That the BWP is in the inactive state means that the BWP is in the unworkable state. For example, signal can't be received/transmitted for an inactive BWP.

(<NUM>) An active BWP is a BWP in an active state, or may be understood as that a signal can be sent or received for the BWP. An inactive BWP is a concept corresponding to the active BWP, and is a BWP in an inactive state, or may be understood as that a signal cannot be sent or received for the BWP.

(<NUM>) BWP switching (switching), used to switch an active BWP. The terminal device may switch the active BWP by receiving a BWP switching command sent by the network device, that is, activate a new BWP and deactivate an old BWP. In the switching method, an identifier of a target active BWP is carried in the BWP switching command, so that the terminal device performs the BWP switching. When the terminal device performs the BWP switching, the terminal device deactivates an original workable BWP, and activates a to-be-switched target BWP. For example, the BWP switching command may be RRC signaling or DCI. If the BWP switching command is the RRC signaling, one switching command may be used by the terminal device to activate a plurality of BWPs. In a carrier aggregation scenario, the switching command may be used by the terminal device to activate a plurality of BWPs on a plurality of carriers. However, because a delay of the RRC signaling is relatively long and a timing is not precise enough, the BWP switching performed by using the RRC signaling is used in rare scenarios, for example, an initial BWP configuration scenario. If the BWP switching command is the DCI, because one piece of the DCI can include a BWP on only one carrier, one switching command can be used by the terminal device to activate only one BWP. In the carrier aggregation scenario, if active BWPs on a plurality of CCs need to be switched at the same time, the DCI needs to be sent for each CC.

(<NUM>) An initial (initial) BWP is used for initial random access of the terminal device, and may include an initial downlink BWP and an initial uplink BWP. It may be understood that in an initial random access process of the terminal device, the terminal device may transmit a signal to the network device or perform a related operation by using the initial BWP.

(<NUM>) A cell is described from a perspective of resource management, mobility management, or a service unit by a higher layer (for example, a protocol layer above a physical layer such as an RRC layer or a medium access control (medium access control, MAC) layer). Coverage of each network device may be divided into one or more cells. One cell may be considered as a cell including specific frequency domain resources, that is, one cell may include a carrier. Therefore, one BWP may also be understood as a part of a bandwidth of one cell. A cell is a common name. For the terminal device, a cell that provides a service for the terminal device is referred to as a serving cell. The cell in this application may also be a serving cell.

(<NUM>) Carrying may mean that a message (for example, a command) is used to carry information or data, or may mean that a message includes information.

(<NUM>) In descriptions of this application, unless otherwise specified, "a plurality of" means two or more, and another quantifier is similar to this. The term "and/or" describes an association relationship between associated objects and represents that three relationships may exist. The character "/" usually indicates an "or" relationship between the associated objects.

(<NUM>) The nouns "network" and "system" are usually interchangeably used, but meanings of the nouns can be understood by a person skilled in the art. The terms "information (information)", "signal (signal)", "message (message)", and "channel (channel)" may be interchangeably used sometimes. It should be noted that meanings expressed by the terms are consistent when differences of the terms are not emphasized.

It should be understood that, in the descriptions of this application, the terms such as "first" and "second" are merely used for differentiation and description, but cannot be understood as indicating or implying relative importance, and cannot be understood as indicating or implying a sequence.

<FIG> is a schematic diagram of a communications system to which an implementation of this application can be used. As shown in <FIG>, a terminal device <NUM> accesses a wireless network, to obtain a service from an external network (for example, the internet) through the wireless network or communicate with another terminal through the wireless network. The wireless network includes a network device <NUM> and a core network device <NUM>. The network device <NUM> is configured to connect the terminal device <NUM> to the wireless network, and the core network device <NUM> is configured to manage the terminal device and provide a gateway for communicating with the external network. It should be understood that an example in which a network architecture includes only two terminal devices <NUM> in <FIG> is used for description. However, the implementations of this application are not limited thereto. For example, the network architecture may further include more terminal devices <NUM>. Similarly, the network architecture may alternatively include more network devices <NUM>, and may alternatively include another device.

It may be understood that the network architecture to which the solutions in the implementations of this application are used may be a <NUM> NR network architecture, or certainly may be a network architecture newly added in the future. Corresponding names of the network device and the terminal device in the implementations of this application may be names of corresponding functions in a wireless communications network. For example, in an NR system, the network device may be a gNB, a TRP, or the like, and the terminal device may be UE, an MS, or the like. In the implementations of this application, the <NUM> NR network architecture is used as an example for description.

In the network architecture shown in <FIG>, the network device (for example, the gNB) may configure carrier aggregation information for the terminal device (for example, the UE), to enable the terminal device to work in a carrier aggregation scenario, that is, the terminal device works on a plurality of CCs. Each piece of the carrier aggregation information is used to configure one CC, each piece of the carrier aggregation information may include a BWP set, the BWP set includes one or more pieces of BWP configuration information, the BWP configuration information may include a quantity of BWPs, a numerology related to the BWP, and the like, and the BWP configuration information is used to configure the BWP on the CC. In the carrier aggregation scenario, the network device may activate one BWP on each of a plurality of CCs for the terminal device at a same moment, the network device may independently send a BWP control command (for example, a BWP switching command or a BWP activation command) for each CC to the terminal device, and the terminal device may activate a new BWP on each CC based on the received BWP control command. However, in some scenarios (for example, a scenario in which network quality is poor), the terminal device may receive only a part of BWP control commands sent by the network device. In this case, if the terminal device executes the part of BWP control commands, an error may occur.

Based on the foregoing problem, an implementation of this application provides a communication method, to optimize a problem of switching an active BWP in a carrier aggregation scenario.

The following uses the network device <NUM> and the terminal device <NUM> as an example to describe the communication method provided in this implementation of this application.

S101: The terminal device <NUM> receives a first command sent by the network device <NUM>. The first command carries a first identifier, the first command is used to activate a first BWP indicated by the first identifier, and the first BWP is a BWP on a first CC.

In this application, the first command may include a BWP activation command, a BWP switching command, or a secondary cell activation command. The BWP activation command is used only to activate a specific BWP. The BWP switching command is used to activate the specific BWP, and deactivate another active BWP on a carrier on which the specific BWP is located. The secondary cell activation command is used to activate a secondary cell and a specific BWP in the secondary cell. The specific BWP in this application is the first BWP.

In this application, the first identifier indicates an identifier that can uniquely identify the first BWP. For example, the identifier may be an identifier configured by the network device <NUM> for the first BWP.

In this application, after receiving the first command, the terminal device <NUM> may determine, based on a capability of the terminal device <NUM>, whether the terminal device <NUM> supports the first BWP and a second BWP in being in an active state at the same time. If the terminal device <NUM> does not support the first BWP and the second BWP in being in the active state at the same time, S102 is performed. If the terminal device <NUM> supports the first BWP and the second BWP in being in the active state at the same time, S103 is performed.

S102: When the terminal device <NUM> does not support the first BWP and the second BWP in being in the active state at the same time, the terminal device <NUM> ignores the first command. The ignoring may also be understood as not executing, ignoring execution of, discarding, or the like.

In this application, the second BWP is a BWP in the active state on a second CC, and the second CC is different from the first CC. That the second CC is different from the first CC may mean that the second CC and the first CC are two types of CCs for the terminal device <NUM>. In this application, the first CC refers to a type of CC on which the terminal device <NUM> receives the corresponding first command, and the second CC refers to a type of CC on which the terminal device <NUM> does not receive the corresponding first command.

Whether the terminal device <NUM> does not support the first BWP and the second BWP in being in the active state at the same time depends on the capability of the terminal device <NUM>. For example, the capability of the terminal device <NUM> supports that only BWPs with a same parameter are in the active state at the same time. For example, the parameter may be an SCS and/or a CP.

According to the foregoing method, the terminal device may determine, based on the capability of the terminal device, to ignore an improper command, to optimize a problem of switching an active BWP in a carrier aggregation scenario.

S103: When the terminal device <NUM> supports the first BWP and the second BWP in being in the active state at the same time, the terminal device <NUM> executes the first command.

If the first command is the BWP activation command, the executing the first command may be understood as activating the first BWP.

If the first command is the BWP switching command, the executing the first command may be understood as activating the first BWP and deactivating a BWP that is in an active state on the first CC before the first BWP is activated.

If the first command is the secondary cell activation command, the executing the first command may be understood as activating a secondary cell of the cell in which the first CC is located, and activating the first BWP of the secondary cell. When the secondary cell activation command is used to activate the BWP in the secondary cell, the secondary cell activation command may not carry the first identifier used to indicate the to-be-activated BWP, and the terminal device <NUM> may determine, based on a first active BWP that is preconfigured, the BWP used when the secondary cell is activated. The first active BWP is a first used BWP that is preconfigured by the network device <NUM> for the terminal device <NUM> when the secondary cell is activated. Optionally, the network device <NUM> may configure a plurality of first active BWPs for the terminal device <NUM>, and the terminal device <NUM> may select one of the plurality of first active BWPs based on active BWPs on other CCs. For example, if only one first active BWP can form an active BWP combination supported by the terminal device <NUM> with the active BWPs on other CCs, the terminal device <NUM> uses the first active BWP as the BWP used when the secondary cell is activated.

It may be understood that either S102 or S103 is performed.

In a possible implementation, the first command may further carry a second identifier, and the second identifier is used to identify the first CC. In this way, after receiving the first command, the terminal device <NUM> may determine, based on the second identifier carried in the first command, that the first command corresponds to the first CC, that is, the first command is a command sent for the first CC. In another possible implementation, if the first command does not carry the second identifier, the terminal device <NUM> may alternatively determine, according to a rule agreed with the network device <NUM>, that the first command corresponds to the first CC. For example, the terminal device <NUM> may agree with the network device <NUM> that if the first command is sent on the first CC, the terminal device <NUM> may determine that the first command corresponds to the first CC.

In this application, there may be one or more first commands. There may be one or more second BWPs and second CCs.

In a possible implementation, when there are a plurality of first commands and there is one second BWP and one second CC, that the terminal device does not support the first BWP and the second BWP in being in the active state at the same time may include: The terminal device does not support a plurality of first BWPs and the second BWP in being in the active state at the same time, where the plurality of first BWPs are first BWPs that are indicated by the first identifier and that are respectively carried in the plurality of first commands; and that the terminal device ignores the first command may include: the terminal device ignores the plurality of first BWPs. In other words, if the terminal device receives the plurality of first commands, when the terminal device does not support the plurality of first BWPs and the second BWP in being in the active state at the same time, the terminal device ignores all the received first commands.

In a possible implementation, when there are a plurality of first commands and there are also a plurality of second BWPs and a plurality of second CCs, that the terminal device does not support the first BWP and the second BWPs in being in the active state at the same time may include: The terminal device does not support the plurality of first BWPs and the plurality of second BWPs in being in the active state at the same time.

The following describes the communication method provided in this implementation of this application by using an example in which the network device <NUM> and the terminal device <NUM> are used, there is one first command, one second BWP, and one second CC, and the first command is a BWP switching command.

Referring to <FIG>, the network device <NUM> in <FIG> configures two CCs for the terminal device <NUM>: a CC <NUM> and a CC <NUM>. Each CC includes two BWPs: a BWP <NUM> and a BWP <NUM>. It is assumed that bandwidths of the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM> are both <NUM>, bandwidths of the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM> are both <NUM>, and BWPs that are in an active state and that are on the CC <NUM> and the CC <NUM> are both the BWPs <NUM>. In this example, it is further assumed that the capability of the terminal device <NUM> includes: supporting the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM> in being in the active state at the same time. It may alternatively be understood as that the terminal device <NUM> supports the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM> in working at the same time and supports the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM> in being in the active state at the same time. It may alternatively be understood as that the terminal device <NUM> supports the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM> in working at the same time, and the terminal device <NUM> does not support the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM> in being in the active state at the same time. It may alternatively be understood as that the terminal device <NUM> does not support the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM> in working at the same time, and does not support the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM> in being in the active state at the same time. It may alternatively be understood as that the terminal device <NUM> does not support the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM> in working at the same time. In other words, that the terminal device <NUM> can support a BWP combination or BWP pairing in the active state at the same time includes: the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM>, and the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM>. That the terminal device <NUM> does not support the BWP combination or the BWP pairing in being in an active state at the same time includes: the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM>, and the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM>. In <FIG>, the terminal device <NUM> may currently transmit a signal by using the active BWP <NUM> on the CC <NUM> and the active BWP <NUM> on the CC <NUM>. It may be understood as that the terminal device <NUM> may currently work on the BWP <NUM> with a narrower bandwidth. When the network device <NUM> expects the terminal device <NUM> to work on the BWP <NUM> with a wider bandwidth, the BWP <NUM> needs to be activated, a BWP switching command may be sent to the terminal device <NUM>, and an identifier of the BWP <NUM> is carried in the BWP switching command, so that the terminal device <NUM> activates the BWP <NUM> based on the BWP switching command and deactivates the BWP <NUM>. After completing BWP switching, the terminal device <NUM> may transmit the signal by using the active BWP <NUM>.

It may be understood that, that two available CCs are configured for the terminal device <NUM> in <FIG> may be understood as that the terminal device <NUM> is in a carrier aggregation scenario. In this scenario, to ensure that the active BWP combination is a BWP combination supported by the terminal device <NUM>, if the BWP <NUM> needs to be activated, the network device <NUM> may send a BWP switching command for the CC <NUM> and a BWP switching command for the CC <NUM> to the terminal device <NUM>, so that the terminal device <NUM> may activate the BWP <NUM> on the CC <NUM> based on the BWP switching command for the CC <NUM>, and activate the BWP <NUM> on the CC <NUM> based on the BWP switching command for the CC <NUM>. Because the BWP switching commands may be lost during transmission, the terminal device <NUM> may receive only one of the BWP switching commands. Certainly, the network device <NUM> may send only one of the BWP switching commands to the terminal device <NUM> because the network device <NUM> makes a wrong decision. In this way, if a BWP switching mechanism in a single-carrier scenario in the prior art is still used, the terminal device <NUM> immediately performs the BWP switching as long as the terminal device <NUM> receives the BWP switching command. This may cause a BWP switching error or a subsequent signal transmission error. However, the communication method provided in this application can be used to optimize a problem of switching an active BWP in a carrier aggregation scenario.

The following describes the communication method provided in the implementations of this application by using an example in which the network device <NUM> and the terminal device <NUM> are used, the first CC is the CC <NUM> shown in <FIG>, the second CC is the CC <NUM> shown in <FIG>, the first command is the BWP switching command for the CC <NUM>, the first BWP is the BWP <NUM> on the CC <NUM> shown in <FIG>, the first identifier is the identifier of the BWP <NUM> on the CC <NUM>, and the second BWP is the BWP <NUM> on the CC <NUM> shown in <FIG>.

S201: The terminal device <NUM> receives the BWP switching command that is for the CC <NUM> and that is sent by the network device <NUM>. The BWP switching command carries the identifier of the BWP <NUM> on the CC <NUM>, and the BWP switching command is used to activate the BWP <NUM> that is on the CC <NUM> and that is indicated by the identifier of the BWP <NUM> on the CC <NUM>.

After receiving the BWP switching command for the CC <NUM>, the terminal device <NUM> may determine, based on the capability of the terminal device <NUM>, whether to support the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM> in being in the active state at the same time. If the terminal device <NUM> does not support the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM> in being in the active state at the same time, S202 is performed. If the terminal device <NUM> supports the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM> in being in the active state at the same time, S203 is performed.

S202: When the terminal device <NUM> does not support the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM> in being in the active state at the same time, the terminal device <NUM> ignores the BWP switching command for the CC <NUM>.

S203: When the terminal device <NUM> supports the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM> in being in the active state at the same time, the terminal device <NUM> executes the BWP switching command for the CC <NUM>. The execution may also be understood as application. The executing the BWP switching command for the CC <NUM> includes activating the BWP <NUM> on the CC <NUM> and deactivating the BWP <NUM> on the CC <NUM>.

Either S202 or S203 is performed. For the specific example in <FIG>, S202 is performed in the foregoing method.

In another specific example, it is assumed that a configuration of the CC and the BWP is still a configuration in <FIG>. In addition, the BWP combination or the BWP pairing that can be supported by the terminal device <NUM> and that can be in the active state at the same time further includes the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM>. As shown in <FIG>, in this example, S203 is performed in the foregoing method.

It should be noted that all BWPs marked as shadow in the accompanying drawings of this application are active BWPs, and no other limitation is imposed.

Optionally, the BWP switching command for the CC <NUM> may carry the identifier of the CC <NUM>. Alternatively, an implicit identifier may be sent on the CC <NUM> to identify that the BWP switching command is for the CC <NUM>. Referring to Table <NUM>, Table <NUM> provides a possible format of the BWP switching command.

Table <NUM> is merely an example for describing the format of the BWP switching command. During actual application, the format of the BWP switching command may further include other content. Details are not described in this application. For the specific example in <FIG>, if Table <NUM> includes a carrier identifier field, the carrier identifier field is the identifier of the CC <NUM>, a BWP identifier field is the identifier of the BWP <NUM> on the CC <NUM>, and the scheduling information may indicate scheduling information of data in the BWP <NUM> on the CC <NUM>.

The foregoing describes how the terminal device implements the method provided in this application when there is one first command, and there is also one second BWP and one second CC. The following further describes how to implement the method provided in this application when there are a plurality of first commands and there is one second BWP and one second CC. The following describes the communication method provided in this implementation of this application by using an example in which the network device <NUM> and the terminal device <NUM> are used, there are two first commands, one second BWP, and one second CC, and the first command is a BWP switching command.

Referring to <FIG>, the network device <NUM> in <FIG> configures three CCs for the terminal device <NUM>: a CC <NUM>, a CC <NUM>, and a CC <NUM>. Each CC includes two BWPs: a BWP <NUM> and a BWP <NUM>. It is assumed that, BWPs that are in an active state and that are on the CC <NUM>, the CC <NUM>, and the CC <NUM> are all the BWPs <NUM>. In this example, it is further assumed that, that the terminal device <NUM> may support a BWP combination or BWP pairing in being in the active state at the same time may include the BWP <NUM> on the CC <NUM>, the BWP <NUM> on the CC <NUM>, and the BWP <NUM> on the CC <NUM>, and the BWP <NUM> on the CC <NUM>, the BWP <NUM> on the CC <NUM>, and the BWP <NUM> on the CC <NUM>. That the terminal device <NUM> does not support the BWP combination or the BWP pairing in being in the active state at the same time may include the BWP <NUM> on the CC <NUM>, the BWP <NUM> on the CC <NUM>, the BWP <NUM> on the CC <NUM>, the BWP <NUM> on the CC <NUM>, the BWP <NUM> on the CC <NUM>, the BWP <NUM> on the CC <NUM>, and the like. Pairing other than the pairing supported by the terminal device <NUM> is pairing not supported, and is not listed one by one herein.

It may be understood that when there are the plurality of first commands, each first command carries one first identifier, and each first command corresponds to one first CC. In other words, there are also a plurality of first identifiers and a plurality of first CCs, and each first CC includes a first BWP. In other words, there are also a plurality of first BWPs.

The following describes the communication method provided in this implementation of this application by using an example the scenario in <FIG> is used and an example in which the first CCs are the CC <NUM> and the CC <NUM> shown in <FIG>, the second CC is the CC <NUM> shown in <FIG>, the first commands include a BWP switching command for the CC <NUM> and a BWP switching command for the CC <NUM>, the first BWPs include the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM> shown in <FIG>, the two first identifiers respectively indicate the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM>, and the second BWP is the BWP <NUM> on the CC <NUM> shown in <FIG>.

S301: The terminal device <NUM> receives the BWP switching command for the CC <NUM> and the BWP switching command for the CC <NUM> that are sent by the network device <NUM>.

After receiving the BWP switching command for the CC <NUM> and the BWP switching command for the CC <NUM>, the terminal device <NUM> may determine, based on the capability of the terminal device <NUM>, whether to support the BWP <NUM> on the CC <NUM>, the BWP <NUM> on the CC <NUM>, and the BWP <NUM> on the CC <NUM> in being in the active state at the same time. If the terminal device <NUM> does not support the BWP <NUM> on the CC <NUM>, the BWP <NUM> on the CC <NUM>, and the BWP <NUM> on the CC <NUM> in being in the active state at the same time, S302 is performed. If the terminal device <NUM> supports the BWP <NUM> on the CC <NUM>, the BWP <NUM> on the CC <NUM>, and the BWP <NUM> on the CC <NUM> in being in the active state at the same time, S303 is performed. Either S302 or S303 is performed. For the specific example in <FIG>, S302 is performed in the foregoing method.

S302: When the terminal device <NUM> does not support the BWP <NUM> on the CC <NUM>, the BWP <NUM> on the CC <NUM>, and the BWP <NUM> on the CC <NUM> in being in the active state at the same time, the terminal device <NUM> ignores the BWP switching command for the CC <NUM> and the BWP switching command for the CC <NUM>.

S303: When the terminal device <NUM> supports the BWP <NUM> on the CC <NUM>, the BWP <NUM> on the CC <NUM>, and the BWP <NUM> on the CC <NUM> in being in the active state at the same time, the terminal device <NUM> executes the BWP switching command for the CC <NUM> and the BWP switching command for the CC <NUM>.

In another specific example, it is assumed that a configuration of the CC and the BWP is still a configuration in <FIG>. In addition, the BWP combination or pairing that can be supported by the terminal device <NUM> and that is in the active state at the same time further includes the BWP <NUM> on the CC <NUM>, the BWP <NUM> on the CC <NUM>, and the BWP <NUM> on the CC <NUM>. As shown in <FIG>, in this example, S303 is performed in the foregoing method.

In this application, a case in which there are a plurality of first commands and there are a plurality of second BWPs and second CCs is similar to an implementation in which there are a plurality of first commands and there is one second BWP and one second CC. Details are not described again in this application.

After ignoring the first command, the terminal device further feeds back, to the network device, that the received first command does not take effect. For example, the terminal device may send a first indication to the network device, where the first indication is used to indicate that the first command does not take effect. For another example, the terminal device may alternatively send a negative acknowledgement NACK message for the first command to the network device. For still another example, the terminal device may alternatively not feed back any information to the network device.

Optionally, the first indication may carry the first identifier. The first indication may be RRC signaling or a MAC CE.

In addition, an implementation of this application further provides another communication method, to optimize a problem of switching an active BWP in a carrier aggregation scenario. This communication method is not claimed in the present application and the description of the terminal device and the network device provided later in the present application should be construed accordingly.

The following uses the network device <NUM> and the terminal device <NUM> as an example to describe the another communication method provided in this implementation of this application.

S401: The terminal device <NUM> receives a first command sent by the network device <NUM>. The first command carries a first identifier, the first command is used to activate a first BWP indicated by the first identifier, and the first BWP is a BWP on a first CC.

For explanations and descriptions of the first command, the first identifier, the first CC, and a second CC, refer to descriptions of the first command, the first identifier, the first CC, and the second CC in the method provided in <FIG>.

S402: The terminal device <NUM> activates the first BWP and a third BWP, where there is an association relationship between the first BWP and the third BWP, and the third BWP is a BWP on the second CC.

The first CC and the second CC may be different or may be same. This is not limited in this application.

After receiving the first command, the terminal device <NUM> activates, based on the first command, the first BWP indicated by the first identifier, and activates the third BWP based on the association relationship between the first BWP and the third BWP.

Optionally, the third BWP is the BWP in an inactive state on the second CC.

Optionally, that there is an association relationship between the first BWP and the third BWP may include: That the terminal device <NUM> supports the first BWP and the third BWP in being in an active state at the same time may also be understood as that the terminal device <NUM> supports the first BWP and the third BWP in working at the same time.

Optionally, the association relationship may be configured by the network device <NUM> for the terminal device <NUM>, or may be prestored by the terminal device <NUM>. When the association relationship is configured for the terminal device <NUM>, before activating the first BWP and the third BWP, the terminal device <NUM> may further receive the association relationship sent by the network device <NUM>. Before sending the association relationship to the terminal device <NUM>, the network device <NUM> may further determine the association relationship. For example, the network device <NUM> may determine the association relationship based on parameters of a plurality of BWPs configured for the terminal device <NUM>. For example, the network device <NUM> may determine BWPs with a same SCS and/or CP as a group of BWPs that have an association relationship.

Optionally, the association relationship may include an association relationship identifier and an identifier, of the BWP, that corresponds to the association relationship identifier. For example, the association relationship between the first BWP and the third BWP may include the association relationship identifier used to indicate the association relationship, and identifiers of the first BWP and the third BWP.

In the communication method shown in <FIG>, there may be one or more first commands. When there are a plurality of first commands, the foregoing method may be separately performed for each first command. This application mainly describes a case in which there is one first command. Details are not described again for a case in which there are the plurality of first commands.

The following describes the another communication method provided in this implementation of this application by using an example in which the network device <NUM> and the terminal device <NUM> are used, there is one first command and one third BWP, and the first command is a BWP switching command. This communication method is not claimed in the present application and the description of the terminal device and the network device provided later in the present application should be construed accordingly.

Referring to <FIG>, a configuration of the terminal device <NUM> by the network device <NUM> in <FIG> is the same as that in <FIG>. A difference lies in that in <FIG>, a BWP <NUM> on a CC <NUM> and a BWP <NUM> on a CC <NUM> are configured to have an association relationship, and a BWP <NUM> on the CC <NUM> and a BWP <NUM> on the CC <NUM> are configured to have an association relationship.

The following describes the another communication method provided in this implementation of this application by using an example in which the network device <NUM> and the terminal device <NUM> are used, the first CC is the CC <NUM> shown in <FIG>, the second CC is the CC <NUM> shown in <FIG>, the first command is the BWP switching command for the CC <NUM>, the first BWP is the BWP <NUM> on the CC <NUM> shown in <FIG>, the first identifier is the identifier of the BWP <NUM> on the CC <NUM>, and the third BWP is the BWP <NUM> on the CC <NUM> shown in <FIG>.

S501: The terminal device <NUM> receives the BWP switching command that is for the CC <NUM> and that is sent by the network device <NUM>, where the BWP switching command carries the identifier of the BWP <NUM> on the CC <NUM>, and the BWP switching command is used to activate the BWP <NUM> on the CC <NUM> indicated by the identifier of the BWP <NUM> on the CC <NUM>.

S502: The terminal device <NUM> activates the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM>.

After receiving the BWP switching command for the CC <NUM>, the terminal device <NUM> activates the BWP <NUM> on the CC <NUM> based on the BWP switching command for the CC <NUM>, and activates the BWP <NUM> on the CC <NUM> based on the association relationship between the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM>. In addition, when activating a new BWP <NUM>, the terminal device <NUM> further needs to deactivate the BWP <NUM>. As shown in <FIG>, according to the method in this application, the terminal device <NUM> not only switches an active BWP on the CC <NUM>, but also needs to switch an active BWP on the CC <NUM>. In this way, even if the terminal device <NUM> does not receive the BWP switching command for the CC <NUM>, the terminal device <NUM> performs BWP switching on the CC <NUM>, so that finally, a combination of the active BWPs on the CC <NUM> and the CC <NUM> is a BWP pairing that is in the active state at the same time and that is supported by the terminal device <NUM>.

In a possible implementation, there are a plurality of third BWPs on a same second CC. In this implementation, before activating the first BWP and the third BWP, the terminal device <NUM> may further receive an association relationship identifier sent by the network device <NUM>. The association relationship identifier indicates an association relationship between the first BWP and a specific third BWP, and the specific third BWP is a BWP included in the plurality of third BWPs. In this implementation, that the terminal device <NUM> activates the first BWP and the third BWP includes: the terminal device <NUM> activates the first BWP and the specific third BWP.

It should be noted that if there is the association relationship between the first BWPs and the plurality of third BWPs, the association relationship between the first BWP and each third BWP corresponds to one association relationship identifier.

The following describes the another communication method provided in this implementation of this application by using an example in which the network device <NUM> and the terminal device <NUM> are used, there is one first command, there are a plurality of third BWPs on the second CC, and the first command is a BWP activation command. This communication method is not claimed in the present application and the description of the terminal device and the network device provided later in the present application should be construed accordingly.

Referring to <FIG>, the network device <NUM> in <FIG> configures two CCs for the terminal device <NUM>: a CC <NUM> and a CC <NUM>. The CC <NUM> includes two BWPs: a BWP <NUM> and a BWP <NUM>. The CC <NUM> includes three BWPs: a BWP <NUM>, a BWP <NUM>, and a BWP <NUM>. It is assumed that BWPs that are in an active state and that are on the CC <NUM> and the CC <NUM> both are the BWPs <NUM>. In addition, in <FIG>, the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM> are configured to have an association relationship, the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM> are configured to have an association relationship, and the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM> are configured to have an association relationship. For ease of description, the association relationship between the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM> is denoted as an association relationship <NUM>, the association relationship between the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM> is denoted as an association relationship <NUM>, and the association relationship between the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM> is denoted as an association relationship <NUM>.

The following describes the another communication method provided in this implementation of this application by using an example in which the network device <NUM> and the terminal device <NUM> are used, the first CC is the CC <NUM> shown in <FIG>, the second CC is the CC <NUM> shown in <FIG>, the first command is the BWP activation command for the CC <NUM>, the first BWP is the BWP <NUM> on the CC <NUM> shown in <FIG>, the first identifier is the identifier of the BWP <NUM> on the CC <NUM>, and the third BWPs include the BWP <NUM> and the BWP <NUM> on the CC <NUM> shown in <FIG>.

S601: The terminal device <NUM> receives at least one association relationship configured by the network device <NUM>. Each association relationship includes an association relationship identifier and an identifier, of the BWP, that corresponds to the association relationship identifier.

For example, for the configuration in <FIG>, the terminal device <NUM> may receive the three association relationships sent by the network device <NUM>. The association relationship <NUM> may include an association relationship identifier A used to indicate the association relationship <NUM>, and identifiers of the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM>. The association relationship <NUM> may include an association relationship identifier B used to indicate the association relationship <NUM>, and identifiers of the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM>. The association relationship <NUM> may include an association relationship identifier C used to indicate the association relationship <NUM>, and identifiers of the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM>.

Optionally, the association relationships may be received by using RRC signaling, MAC layer signaling, or physical layer signaling. This is not limited in this application.

Optionally, the CC <NUM> and the CC <NUM> may be different or may be same. This is not limited in this application.

Optionally, the association relationships may alternatively be associated with CC identifiers. For example, an association relationship for each CC may be configured for the CC. For example, the association relationship <NUM> sent on the CC <NUM> is used to indicate that the associated BWPs are the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM>. The association relationship <NUM> sent on the CC <NUM> is used to indicate that the associated BWPs are the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM>.

It should be noted that S601 is an optional step. S601 may be performed once each time the method is implemented. Certainly, S601 may also be performed once when the method is implemented for the first time, and the terminal device <NUM> may store the plurality of association relationships, to be used in subsequent implementation of the method.

S602: The terminal device <NUM> receives the BWP activation command sent by the network device <NUM>, where the BWP activation command carries the association relationship identifier. For example, the BWP activation command may carry the association relationship identifier C.

Optionally, the BWP activation command may be RRC signaling, MAC layer signaling, or physical layer signaling.

Referring to Table <NUM>, Table <NUM> provides a possible format of the BWP activation command.

Table <NUM> is merely an example for describing the format of the BWP activation command. During actual application, the format of the BWP activation command may further include other content. Details are not described in this application. For the specific examples in <FIG> and <FIG>, if Table <NUM> includes a CC identifier field, the CC identifier field is the identifier of the CC <NUM>.

S603: The terminal device <NUM> determines, based on the received association relationship identifier, the association relationship corresponding to the association relationship identifier, and activates the BWP that corresponds to the identifier of the BWP and that is included in the association relationship.

For example, it is assumed that the association relationship identifier received by the terminal device <NUM> in S602 is the association relationship identifier C. In this case, the terminal device <NUM> may determine, based on the association relationship identifier C, that the corresponding association relationship is the association relationship <NUM>, and may further activate the BWPs corresponding to the identifiers, of the BWP <NUM> on the CC <NUM> and the BWP <NUM> on the CC <NUM>, that are included in the association relationship <NUM>.

Optionally, the terminal device <NUM> may determine, based on the association relationship identifier and the identifier, of the CC, that is for sending the BWP activation command carrying the association relationship identifier, the BWP corresponding to the association relationship identifier. For example, if the terminal device <NUM> receives the BWP activation command on the CC <NUM>, and the BWP activation command includes the association relationship identifier <NUM>, the terminal device <NUM> determines the BWP corresponding to the association relationship identifier <NUM> corresponding to the CC <NUM>, and activates the BWP.

It should be noted that when activating a new BWP, the terminal device <NUM> may further perform a deactivation operation on the BWP that is in the active state before the BWP activation command is executed.

According to the foregoing method, the terminal may activate the plurality of BWPs on the plurality of CCs or the plurality of BWPs on one CC based on one BWP activation command. The terminal device <NUM> may activate not only the BWPs on the CC <NUM>, but also the BWPs on the CC <NUM>. In this way, even if the terminal device <NUM> does not receive the BWP activation command for the CC <NUM>, the terminal device <NUM> performs BWP switching on the CC <NUM> based on the association relationship, so that finally, a combination of the active BWPs on the CC <NUM> and the CC <NUM> is a BWP pairing that is in the active state at the same time and that is supported by the terminal device <NUM>.

Based on a same inventive concept, an implementation of this application further provides a terminal device. The terminal device may have a structure shown in <FIG>, and has behavior functions of the terminal device <NUM> in the foregoing method implementations. As shown in <FIG>, the terminal device <NUM> may include a processing module <NUM> and a transceiver module <NUM>. During implementation, the terminal device <NUM> may further include a storage module <NUM>. The storage module <NUM> may be coupled to the processing module <NUM>, and is configured to store a program and an instruction that are needed by the processing module <NUM> to perform functions.

Based on the communication method shown in <FIG>, the processing module <NUM> in the terminal device <NUM> shown in <FIG> may be configured to for the terminal device <NUM> to perform the steps shown in S102 or S103, and the transceiver module <NUM> may be configured to for the terminal device <NUM> to perform the steps shown in S101.

In a possible design, in S101, there may be a plurality of first commands, and each first command corresponds to one first CC. In this design, that the processing module <NUM> is configured to determine that the processing module <NUM> does not support the first BWP and a second BWP in being in the active state at the same time includes:.

In a possible design, there are a plurality of second BWPs and a plurality of second CCs. In this design, that the processing module <NUM> is configured to determine that the processing module <NUM> does not support the first BWP and a second BWP in being in an active state at the same time includes:
The processing module <NUM> is configured to determine that the processing module does not support the plurality of first BWPs and the plurality of second BWPs in being in the active state at the same time.

The transceiver module <NUM> is further configured to send a first indication to the network device, where the first indication is used to indicate that the first command does not take effect; or
the transceiver module <NUM> is further configured to send a negative acknowledgement NACK message for the first command to the network device.

In a possible design, the first indication carries the first identifier.

In a possible design, the first command carries a second identifier, and the second identifier is used to identify the first CC.

Based on the communication method shown in <FIG>, the processing module <NUM> in the terminal device <NUM> shown in <FIG> may be configured to for the terminal device <NUM> to perform the steps shown in S402, and the transceiver module <NUM> may be configured to for the terminal device <NUM> to perform the steps shown in S401. This implementation is not claimed in the present application.

In a possible design, in S402, that there is an association relationship between the first BWP and a third BWP includes: The processing module <NUM> supports the first BWP and the third BWP in being in an active state at the same time.

In a possible design, there are a plurality of third BWPs on a same second CC. In this design, the processing module <NUM> is further configured to: before activating the first BWP and the third BWP, receive, through the transceiver module <NUM>, an association relationship identifier sent by the network device, where the association relationship identifier indicates an association relationship between the first BWP and a specific third BWP, and the specific third BWP is a BWP included in the plurality of third BWPs; and activate the first BWP and the specific third BWP.

In a possible design, the processing module <NUM> is further configured to: before activating the first BWP and the third BWP, receive, through the transceiver module <NUM>, the association relationship sent by the network device.

In a possible design, the association relationship is prestored by the processing module <NUM>.

In addition, the terminal device in this implementation of this application may further have a structure of a terminal device <NUM> shown in <FIG>. A processor <NUM> in the terminal device <NUM> shown in <FIG> may be configured to implement the functions of the processing module <NUM>. For example, the processor <NUM> may be configured for the terminal device <NUM> to perform the steps shown in S102 and/or S402. The transceiver <NUM> may be configured to implement the functions of the transceiver module <NUM>. For example, the transceiver <NUM> may be configured for the terminal device <NUM> to perform the steps shown in S101 and/or S401. In addition, the transceiver <NUM> may be coupled to an antenna <NUM>, and is configured to support the terminal device <NUM> in performing communication. For example, the terminal device <NUM> may further include a memory <NUM>, and the memory <NUM> stores a computer program and an instruction. The memory <NUM> may be coupled to the processor <NUM> and/or the transceiver <NUM>, and is configured to support the processor <NUM> in invoking the computer program and the instruction in the memory <NUM> to implement the steps related to the terminal device <NUM> in the methods provided in the implementations of this application. In addition, the memory <NUM> may be further configured to store data in the method implementations of this application. For example, the memory <NUM> is configured to store data and an instruction that are necessary for supporting the transceiver <NUM> in implementing interaction, and/or is configured to store configuration information that is necessary for the terminal device <NUM> to perform the methods in the implementations of this application.

Based on a same inventive concept, an implementation of this application further provides a network device. The network device may have a structure shown in <FIG>, and has behavior functions of the network device <NUM> in the foregoing method implementations. As shown in <FIG>, the network device <NUM> may include a processing module <NUM> and a transceiver module <NUM>. During implementation, the network device <NUM> may further include a storage module <NUM>. The storage module <NUM> may be coupled to the processing module <NUM>, and is configured to store a program and an instruction that are needed by the processing module <NUM> to perform functions.

Based on the communication method shown in <FIG>, the transceiver module <NUM> in the network device <NUM> shown in <FIG> may be configured to for the network device to perform the steps shown in S101, and perform receiving of the first indication sent by the terminal device, or receiving of the negative acknowledgement NACK message that is sent by the terminal device and that is specific to the first command.

In a possible design, there may be a plurality of first commands, and each first command corresponds to one first CC.

Based on the communication method shown in <FIG>, the processing module <NUM> in the network device <NUM> shown in <FIG> may be configured for the network device <NUM> to determine the association relationship and send the association relationship to the terminal device, and the transceiver module <NUM> may be configured for the network device <NUM> to perform the steps shown in S401. This implementation is not claimed in the present application.

In a possible design, that there is the association relationship between the first BWP and a third BWP in S401 and S402 includes:
The processing module <NUM> supports the first BWP and the third BWP in being in an active state at the same time.

In a possible design, there are a plurality of third BWPs on a same second CC. In this design, the processing module <NUM> is further configured to: send an association relationship identifier to the terminal device through the transceiver module <NUM>, where the association relationship identifier indicates an association relationship between the first BWP and a specific third BWP, and the specific third BWP is a BWP included in the plurality of third BWPs.

In a possible design, the processing module <NUM> is specifically configured to:
determine the association relationship based on parameters of a plurality of BWPs configured for the terminal device.

In addition, the network device in this implementation of this application may further have a structure of a network device <NUM> shown in <FIG>. A processor <NUM> in the network device <NUM> shown in <FIG> may be configured to implement the functions of the processing module <NUM>. For example, the processor <NUM> may be configured for the network device <NUM> to perform the steps such as determining the association relationship between the first BWP and the second BWP. The transceiver <NUM> may be configured to implement the functions of the transceiver module <NUM>. For example, the transceiver <NUM> may be configured for the network device <NUM> to perform the steps shown in S101 and/or S401. In addition, the transceiver <NUM> may be coupled to an antenna <NUM>, and is configured to support the network device <NUM> in performing communication. For example, the network device <NUM> may further include another interface <NUM>, configured to support the network device <NUM> in performing interaction in a wired manner. For example, the another interface <NUM> may be a fiber link interface, an ethernet interface, a copper wire interface, or the like. For example, the network device <NUM> may further include a memory <NUM>, and the memory <NUM> stores a computer program and an instruction. The memory <NUM> may be coupled to the processor <NUM> and/or the transceiver <NUM>, and is configured to support the processor <NUM> in invoking the computer program and the instruction in the memory <NUM> to implement the steps related to the network device <NUM> in the methods provided in the implementations of this application. In addition, the memory <NUM> may be further configured to store data in the method implementations of this application. For example, the memory <NUM> is configured to store data and an instruction that are necessary for supporting the transceiver <NUM> in implementing interaction.

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

When the communications apparatus is a terminal device, <FIG> is a simplified schematic structural diagram of the terminal device. For ease of understanding and convenience of figure 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 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, the processor performs baseband processing on the to-be-sent data, and 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 in an electromagnetic wave form 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, only one memory and one processor are shown in <FIG>. 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 implementation of this application.

In this implementation of this application, the antenna and the radio frequency circuit that have a transceiver function 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 implementations, and the processing unit <NUM> is configured to perform an operation other than the receiving operation and the sending operation of the terminal device in the foregoing method implementations.

For example, in an implementation, the transceiver unit <NUM> is configured to perform a receiving operation on the terminal device in S101 in <FIG>, and/or the transceiver unit <NUM> is further configured to perform another sending and receiving step on the terminal device in the implementations of this application. The processing unit <NUM> is configured to perform S102 or S103 in <FIG>. The processing unit <NUM> is further configured to perform another processing step on the terminal device in the implementations of this application.

For another example, in another implementation, the transceiver unit <NUM> is configured to perform a receiving operation on the terminal device side in S201 in <FIG>, and/or the transceiver unit <NUM> is further configured to perform another sending and receiving step on the terminal device side in the implementations of this application. The processing unit <NUM> is configured to perform S202 or S203 in <FIG>, and/or the processing unit <NUM> is further configured to perform another processing step on the terminal device side in the implementations of this application.

For still another example, in still another implementation, the transceiver unit <NUM> is configured to perform a receiving operation on the terminal device side in S301 in <FIG>, and/or the transceiver unit <NUM> is further configured to perform another sending and receiving step on the terminal device side in the implementations of this application. The processing unit <NUM> is configured to perform S302 or S303 in <FIG>, and/or the processing unit <NUM> is further configured to perform another processing step on the terminal device side in the implementations of this application.

For still another example, in still another implementation, the transceiver unit <NUM> is configured to perform a receiving operation on the terminal device in S401 in <FIG>, and/or the transceiver unit 1910is further configured to perform another sending and receiving step on the terminal device side in the implementations of this application. The processing unit <NUM> is configured to perform S402 in <FIG>, and/or the processing unit <NUM> is further configured to perform another processing step on the terminal device side in the implementations of this application.

For still another example, in still another implementation, the transceiver unit <NUM> is configured to perform a receiving operation on the terminal device side in S501 in <FIG>, and/or the transceiver unit <NUM> is further configured to perform another sending and receiving step on the terminal device side in the implementations of this application. The processing unit <NUM> is configured to perform S502 in <FIG>, and/or the processing unit <NUM> is further configured to perform another processing step on the terminal device side in the implementations of this application.

For still another example, in still another implementation, the transceiver unit <NUM> is configured to perform a receiving operation on the terminal device side in S601 in <FIG>, and/or the transceiver unit <NUM> is further configured to perform another sending and receiving step on the terminal device side in the implementations of this application. The processing unit <NUM> is configured to perform S602 in <FIG>, and/or the processing unit <NUM> is further configured to perform another processing step on the terminal device side in the implementations of this application.

When the communications 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 communications interface. The processing unit is a processor, a microprocessor, or an integrated circuit integrated on the chip.

When the communications apparatus in this implementation is a terminal device, refer to a device shown in <FIG>. In an example, the device can implement the functions similar to those of the processor <NUM> in <FIG>. In <FIG>, the device includes a processor <NUM>, a data sending processor <NUM>, and a data receiving processor <NUM>. The processing module <NUM> in the foregoing implementation may be the processor <NUM> in <FIG>, and completes corresponding functions. The transceiver module <NUM> in the foregoing implementation 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 limitative descriptions of this implementation.

<FIG> shows another form of this implementation. A processing apparatus <NUM> includes modules such as a modulation subsystem, a central processing subsystem, and a peripheral subsystem. The communications apparatus in this implementation 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> implements the functions of the processing module <NUM>, and the interface <NUM> implements the functions of the transceiver module <NUM>. In another variation, the modulation subsystem includes a memory <NUM>, the processor <NUM>, and a program that is stored in the memory <NUM> and that can be run on the processor. When executing the program, the processor <NUM> implements the method on the terminal device side in the foregoing method implementations. It should be noted that the memory <NUM> may be nonvolatile or volatile. The memory <NUM> may be located in the modulation subsystem, or may be located in the processing apparatus <NUM>, provided that the memory <NUM> can be connected to the processor <NUM>.

In another form of this implementation, a computer-readable storage medium is provided. The computer-readable storage medium stores an instruction. When the instruction is executed, the methods on the terminal device side in the foregoing method implementations are performed.

In another form of this implementation, a computer program product that includes an instruction is provided. When the instruction is executed, the methods on the terminal device side in the foregoing method implementations are performed.

It should be understood that, the processor mentioned in the implementations of the present application may be a central processing unit (Central Processing Unit, CPU), or the processor 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 logical device, a discrete gate, or a transistor logical 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 further be understood that the memory in the implementations of the present application may be a volatile memory or a nonvolatile memory, or may include a volatile memory and a nonvolatile memory. The nonvolatile 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 (Random Access Memory, RAM), 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 further understood that "first", "second", "third", "fourth", and various numbers in this specification are merely used for differentiation for ease of description, and are not construed as a limitation to the scope of this application.

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

This application is described with reference to the flowcharts and/or block diagrams of the method, the device (system), and the computer program product according to the implementations of this application. It should be understood that computer program instructions may be used to implement each process and/or each block in the flowcharts and/or the block diagrams and a combination of a process and/or a block in the flowcharts and/or the block diagrams. These computer program instructions may be provided for a general-purpose computer, a special-purpose computer, an embedded processor, or a processor of another programmable data processing device to generate a machine, so that the instructions executed by the computer or the processor of the another programmable data processing device generate an apparatus for implementing specific functions in one or more processes in the flowcharts and/or in one or more blocks in the block diagrams.

These computer program instructions may be stored in a computer-readable memory that can instruct the computer or the another programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate an artifact that includes an instruction apparatus. The instruction apparatus implements specific functions in one or more processes in the flowcharts and/or in one or more blocks in the block diagrams.

These computer program instructions may be loaded onto the computer or the another programmable data processing device, so that a series of operations and steps are performed on the computer or the another programmable device, thereby generating computer-implemented processing. Therefore, the instructions executed on the computer or the another programmable device provide steps for implementing specific functions in one or more processes in the flowcharts and/or in one or more blocks in the block diagrams.

Claim 1:
A communication method performed by a terminal device, the method comprising:
receiving (S101) a first command sent by a network device, wherein the first command carries a first identifier, the first command is used to activate a first bandwidth part, BWP, indicated by the first identifier, and the first BWP is a BWP on a first component carrier, CC; and characterized by:
ignoring (S102) the first command when the terminal device does not support the first BWP and a second BWP in being in an active state at the same time, wherein the second BWP is a BWP in the active state on a second CC, and the second CC is different from the first CC;
wherein after the ignoring the first command, the method further comprises:
sending a first indication to the network device, wherein the first indication is used to indicate that the first command does not take effect; or
sending a negative acknowledgement, NACK, message for the first command to the network device.