Patent Publication Number: US-2023163920-A1

Title: Dci transmission method, terminal, and base station

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. patent application Ser. No. 17/094,289 filed on Nov. 10, 2020, which is a continuation application of PCT International Application No. PCT/CN2019/085104 filed on Apr. 30, 2019, which claims priority to Chinese Patent Application No. 201810445110.7 filed in China on May 10, 2018. All of the disclosures are incorporated herein by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     This disclosure relates to the field of communications technologies, and in particular, to a downlink control information (Downlink Control Information, DCI) transmission method, a terminal, and a base station. 
     BACKGROUND 
     In a new radio (New Radio, NR) system, states of a terminal include a connected state, an idle state, and an inactive state, and an update notification of system information may be transmitted on a physical downlink shared channel (Physical Downlink Shared Channel downlink, PDSCH), or may be transmitted on a physical downlink control channel (Physical Downlink Control Channel, PDCCH). However, in a communications system of related technologies, update notifications of system information are transmitted on different channels for terminals in different states. For example, an update notification of system information is transmitted on a PDSCH to ensure performance of a terminal in an idle state, and an update notification of system information is transmitted on a PDCCH to ensure performance of a terminal in a connected state. In this way, update notifications of system information need to be separately transmitted on the PDSCH and the PDCCH, resulting in relatively large signaling transmission overheads. 
     SUMMARY 
     Embodiments of this disclosure provide a DCI transmission method, a terminal, and a base station, so as to resolve the problem of relatively large signaling transmission overheads. 
     According to a first aspect, an embodiment of this disclosure provides a DCI transmission method, applied to a terminal and including: 
     receiving DCI, where when there is simultaneously in a network a paging message for an idle-state terminal and a change of system information, the DCI carries 
     PDSCH scheduling information for the paging message and a short message; otherwise, the DCI carries the scheduling information or the short message, where the short message is used to indicate the change of system information; and 
     obtaining at least one of the scheduling information or the short message from the DCI. 
     According to a second aspect, an embodiment of this disclosure provides a DCI transmission method, applied to a base station and including: 
     generating DCI, where when there is simultaneously in a network a paging message for an idle-state terminal and a change of system information, the DCI carries PDSCH scheduling information for the paging message and a short message; otherwise, the DCI carries the scheduling information or the short message, where the short message is used to indicate the change of system information; and 
     transmitting the DCI on a PDCCH. 
     According to a third aspect, an embodiment of this disclosure provides a terminal, including: 
     a receiving module, configured to receive DCI, where when there is simultaneously in a network a paging message for an idle-state terminal and a change of system information, the DCI carries PDSCH scheduling information for the paging message and a short message; otherwise, the DCI carries the scheduling information or the short message, where the short message is used to indicate the change of system information; and 
     an obtaining module, configured to obtain at least one of the scheduling information or the short message from the DCI. 
     According to a fourth aspect, an embodiment of this disclosure provides a base station, including: 
     a generation module, configured to generate DCI, where when there is simultaneously in a network a paging message for an idle-state terminal and a change of system information, the DCI carries PDSCH scheduling information for the paging message and a short message; otherwise, the DCI carries the scheduling information or the short message, where the short message is used to indicate the change of system information; and 
     a transmission module, configured to transmit the DCI on a PDCCH. 
     According to a fifth aspect, an embodiment of this disclosure provides a terminal, including a memory, a processor, and a computer program stored in the memory and capable of running on the processor, where when the computer program is executed by the processor, the steps of the DCI transmission method on a terminal side provided in the embodiments of this disclosure are implemented. 
     According to a sixth aspect, an embodiment of this disclosure provides a base station, including a memory, a processor, and a computer program stored in the memory and capable of running on the processor, where when the computer program is executed by the processor, the steps of the DCI transmission method on a base station side provided in the embodiments of this disclosure are implemented. 
     According to a seventh aspect, an embodiment of this disclosure provides a computer-readable storage medium, where the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the DCI transmission method on a terminal side provided in the embodiments of this disclosure are implemented, or when the computer program is executed by a processor, the steps of the DCI transmission method on a base station side provided in the embodiments of this disclosure are implemented. 
     In the embodiments of this disclosure, the DCI is received, where when there is simultaneously in the network the paging message for the idle-state terminal and the change of system information, the DCI carries the PDSCH scheduling information for the paging message and the short message; otherwise, the DCI carries the scheduling information or the short message, where the short message is used to indicate the change of system information. At least one of the scheduling information or the short message is obtained from the DCI. This can reduce signaling transmission overheads. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a structural diagram of a network system to which embodiments of this disclosure are applicable; 
         FIG.  2    is a flowchart of a DCI transmission method according to an embodiment of this disclosure; 
         FIG.  3    is a flowchart of another DCI transmission method according to an embodiment of this disclosure; 
         FIG.  4    is a schematic diagram of DCI according to an embodiment of this disclosure; 
         FIG.  5    is a schematic diagram of another type of DCI according to an embodiment of this disclosure; 
         FIG.  6    is a schematic diagram of another type of DCI according to an embodiment of this disclosure; 
         FIG.  7    is a schematic diagram of another type of DCI according to an embodiment of this disclosure; 
         FIG.  8    is a flowchart of another DCI transmission method according to an embodiment of this disclosure; 
         FIG.  9    is a structural diagram of a terminal according to an embodiment of this disclosure; 
         FIG.  10    is a structural diagram of a base station according to an embodiment of this disclosure; 
         FIG.  11    is a structural diagram of another terminal according to an embodiment of this disclosure; and 
         FIG.  12    is a structural diagram of another base station according to an embodiment of this disclosure. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The following clearly describes the technical solutions in the embodiments of this disclosure with reference to the accompanying drawings in the embodiments of this disclosure. Apparently, the described embodiments are some rather than all of the embodiments of this disclosure. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of this disclosure without creative efforts shall fall within the protection scope of this disclosure. 
     In the specification and claims of this application, the terms “include”, “comprise”, and any other variants thereof are intended to cover the non-exclusive inclusion. For example, a process, method, system, product, or device that includes a list of steps or units is not necessarily limited to those expressly listed steps or units, but may include other steps or units not expressly listed or inherent to such process, method, system, product, or device. In addition, in the specification and claims, the use of “and/or” represents presence of at least one of the connected objects. For example, “A and/or B” indicates that the following three cases: only A, only B, or both A and B. 
     In the embodiments of this disclosure, the terms “exemplary” or “for example” are used to represent an example, an illustration, or a description. Any embodiment or design solution described as “exemplary” or “for example” in the embodiments of this disclosure should not be construed as preferred or advantageous over other embodiments or design solutions. To be precise, the terms such as “exemplary” or “for example” are intended to present a related concept in a specific manner. 
     The following describes the embodiments of this disclosure with reference to the accompanying drawings. A DCI transmission method, a terminal, and a base station provided in the embodiments of this disclosure may be applied to a wireless communications system. The wireless communications system may be a 5G system, or an evolved long term evolution (Evolved Long Term Evolution, eLTE) system, or a later evolved communications system. 
     Referring to  FIG.  1   ,  FIG.  1    is a structural diagram of a network system to which the embodiments of this disclosure are applicable. As shown in  FIG.  1   , the network system includes a terminal  11  and a base station  12 . The terminal  11  may be user equipment (User Equipment, UE) or other terminal-side devices such as a mobile phone, a tablet personal computer (Tablet Personal Computer), a laptop computer (Laptop Computer), a personal digital assistant (personal digital assistant, PDA), a mobile Internet device (Mobile Internet Device, MID), or a wearable device (Wearable Device). It should be noted that the terminal  11  is not limited to any specific type in the embodiments of this disclosure. The base station  12  may be a 4G base station, or a 5G base station, or a base station of a later version, or a base station in another communications system, or is referred to as a node B, an evolved node B, or other terms in the field. The base station is not limited to a specific technical term provided that a same technical effect is achieved. In addition, the base station  12  may be a master node (Master Node, MN) or a secondary node (Secondary Node, SN). It should be noted that the 5G base station is merely used as an example in the embodiments of this disclosure, rather than limiting the specific type of the base station. 
     Referring to  FIG.  2   ,  FIG.  2    is a flowchart of a DCI transmission method according to an embodiment of this disclosure. The method is applied to a terminal, and the terminal may be a connected-state terminal, an idle-state terminal or an inactive-state terminal. As shown in  FIG.  2   , the method includes the following steps. 
     Step  201 : Receive DCI, where when there is simultaneously in a network a paging message for an idle-state terminal and a change of system information, the DCI carries PDSCH scheduling information for the paging message (Paging PDSCH scheduling) and a short message (short message); otherwise, the DCI carries the scheduling information or the short message, where the short message is used to indicate the change of system information. 
     The receiving DCI may be receiving the DCI on a PDCCH, and specifically, may be that a base station transmits the DCI on the PDCCH. 
     That when there is simultaneously in the network the paging message for the idle-state terminal and the change of system information, the DCI carries the PDSCH scheduling information for the paging message and the short message; otherwise, the DCI carries the scheduling information or the short message may be that: when there is simultaneously in the network the paging message for the idle-state terminal and the change of system information, the DCI carries the scheduling information and the short message; when there is only the paging message for the idle-state terminal in the network, the DCI carries the scheduling information; and when there is only the change of system information in the network, the DCI carries the short message. That there is simultaneously in the network the paging message for the idle-state terminal and the change of system information may be that there is simultaneously the paging message and the change of system information for the base station or the base station needs to simultaneously send the paging message and the change of system information; or may be that there is the change of system information after the base station has sent the paging message, or when the base station is sending the paging message, or when the base station is to send the paging message. 
     The paging message may be a paging message for the idle-state terminal or the inactive-state terminal. In this case, a PDSCH of the paging message may also be referred to as a PDSCH corresponding to the paging message, and the scheduling information may include at least one of the following: 
     frequency domain resource (Frequency domain resource) information, time domain resource (Time domain resource) information, mapping information between a virtual resource block (Virtual Resource Block, VRB) and a physical resource block (physical resource block, PRB), modulation and coding scheme (modulation and coding scheme), transport block scaling (Transport Block scaling, TB scaling), or reserved bits (bit), where the TB scaling may be 2 bits, and the reserved bits may be 15 bits, which are not limited. 
     The change of system information may include at least one of a change of ordinary system information or a change of public safety system information. In addition, if the short message has remaining bits, the remaining bits are reserved bits. The remaining bits herein are bits other than those indicating the change of system information and the change of public safety system information. 
     It should be noted that in this embodiment of this disclosure, the ordinary system information may also be referred to as system information, and the ordinary system information may be system information other than the public safety system information. The public safety system information may include at least one of earthquake and tsunami warning system (Earthquake and Tsunami Warning System, ETWS) information or commercial mobile alert service (Commercial Mobile Alert Service, CMAS) information. 
     In addition, in this embodiment of this disclosure, the short message may include M bits, and the M bits may be used to indicate the change of system information, and M is an integer greater than 0. The change of system information may include at least one of the following: 
     whether all system information (referred to as the ordinary system information) has changed, whether all system information (including the public safety system information and the ordinary system information) has changed, whether all system information except a master information block (Master Information Block, MIB) has changed, whether all system information except the MIB and system information block (System information Block, SIB)  1  has changed, whether per-SIB (per-SIB) messages have changed, whether per system information messages (per-SI message) have changed, or whether the public safety system information (CMAS and/or ETWS) has changed. In addition, the rest are reserved bits. The SI described above stands for system information (System Information). 
     It should be noted that in this embodiment of this disclosure, the change of system information may also be referred to as an alteration of system information. 
     Step  202 : Obtain at least one of the scheduling information or the short message from the DCI. 
     In this step, at least one of the scheduling information or the short message may be obtained by parsing (or demodulating) the DCI. For example, if the DCI carries the scheduling information and the short message, the scheduling information and the short message are obtained in step  202 . If the DCI carries the scheduling information or the short message, the scheduling information or the short message is obtained in step  202 . 
     In the foregoing method, because there is simultaneously in the network the physical downlink shared channel PDSCH scheduling information for the paging message and the change of system information, the DCI carries the scheduling information and the short message. In this way, in a case in which updating the system information and paging the idle-state terminal take place at the same time, the PDSCH scheduling information for the paging message and the short message are carried in the DCI, thereby reducing a delay for paging the idle-state terminal and also reducing a delay for obtaining an update indication of system information by the idle-state terminal and the connected-state terminal. When updating of the system information and paging of the idle-state terminal do not occur at the same time, the PDSCH scheduling information for the paging message or the short message may be carried in DCI, so as to transmit the scheduling information or indicate the change of system information. In addition, carrying at least one of the scheduling information or the short message in the DCI can meet requirements of both the connected-state terminal and the idle-state terminal, because both the connected-state terminal and the idle-state terminal are capable of demodulating the DCI. Certainly, this embodiment of this disclosure may also be applied to the inactive-state terminal, with the same beneficial effect achieved. 
     In addition, in this embodiment of this disclosure, the scheduling information carried in the DCI may be referred to as a scheduling information field, and the short message carried in the DCI may be referred to as a short message field. The DCI may further include a reserved field, and the reserved field includes reserved bits. Certainly, this is not limited thereto, because the DCI may further include a header (header) field or an indication field in some implementations. In addition, in this embodiment of this disclosure, because the short message is used to indicate the change of system information, the short message may also be referred to as another name, for example, change indication information of system information. 
     It should be noted that the foregoing method provided in this embodiment of this disclosure may be applied to a 5G NR system, which, however, is not limited thereto. The method can be applied to other communications systems provided that the same functions can be implemented, for example, applied to a 4G or 6G system or other communications systems to which the change of system information and transmission of the scheduling information are applied. 
     In this embodiment of this disclosure, the DCI is received. The DCI carries at least one of the PDSCH scheduling information for the paging message or the short message, and the short message is used to indicate the change of system information. At least one of the scheduling information or the short message is obtained from the DCI. This can reduce signaling transmission overheads, and can also achieve the effects of reducing a delay for obtaining an update indication of system information by the idle-state terminal and the connected-state terminal, and further reducing a delay for paging the idle-state terminal. 
     Referring to  FIG.  3   ,  FIG.  3    is a flowchart of another DCI transmission method according to an embodiment of this disclosure. The method is applied to a terminal, and as shown in  FIG.  3   , includes the following steps. 
     Step  301 : Receive DCI, where when there is simultaneously in a network a paging message for an idle-state terminal and a change of system information, the DCI carries PDSCH scheduling information for the paging message and a short message; otherwise, the DCI carries the scheduling information or the short message, where the short message is used to indicate the change of system information; and the DCI further includes indication information and the indication information is used to indicate content carried in the DCI. 
     The indication information may be used to indicate whether the DCI carries the scheduling information and/or carries the short message. In this way, the indication information allows the terminal to know content carried in the DCI, so that the terminal can demodulate the DCI based on a requirement of the terminal, thereby reducing power consumption of the terminal. For example, when the indication information indicates that the DCI carries no short message, and a connected-state terminal does not require the scheduling information, the scheduling information may not be obtained to reduce power consumption of the terminal. 
     In an optional implementation, the DCI includes a header field, and the header field includes the indication information. 
     The indication information indicates that the DCI carries at least one of the scheduling information or the short message; or 
     a portion of bits in the indication information is used to indicate whether the DCI carries the scheduling information, and the other portion of bits is used to indicate whether the DCI carries the short message. 
     That the indication information indicates that the DCI carries at least one of the scheduling information or the short message may be that the indication information indicates, by using a code point, that the DCI carries at least one of the scheduling information or the short message, or may be that the indication information indicates, in a joint coding manner, that the DCI carries at least one of the scheduling information or the short message. In addition, the indication information may be indication information of N bits, where N is a positive integer. For example, N is 2. As shown in  FIG.  4   , the indication information is 10, indicating that DCI carries the short message, 01 indicates that the DCI carries the scheduling information, and 11 indicates that the DCI carries the scheduling information and the short message. Indicating, by using the indication information, that the DCI carries at least one of the scheduling information or the short message can reduce code points of the indication information. For example, indicating the scheduling information or the short message requires only three code points, so that another code point (for example, 00) may be reserved for indicating other cases (case) later. 
     That a portion of bits in the indication information is used to indicate whether the DCI carries the scheduling information, the other portion of bits is used to indicate whether the DCI carries the short message may be that the indication information includes two parts of bits, one part is used to indicate whether the DCI carries the scheduling information, and the other part is used to indicate whether the DCI carries the short message. For example, the indication information is N bits, where N is 2. As shown in  FIG.  5   , the first bit is used to indicate whether the DCI carries the short message. When the first bit is 1, it indicates that the DCI carries the short message; when the first bit is 0, it indicates that the DCI carries no short message. The second bit is used to indicate whether the DCI carries the scheduling information. When the second bit is 1, it indicates that the DCI carries the scheduling information; when the first bit is 0, it indicates that the DCI does not carry the scheduling information. In this way, the scheduling information and the short message can each be indicated by using a dedicated bit, reducing complexity. 
     In addition, it should be noted that, in this embodiment of this disclosure, locations of the scheduling information and the short message in the DCI are not limited, which, for example, may be locations shown in  FIG.  4    and  FIG.  5   , or may be that the scheduling information is in the front and the short message is in the back. 
     In the foregoing implementation, the DCI may include a header field (header field)+a short message field and/or a paging PDSCH scheduling field+a reserved field, where the short message field and/or the paging PDSCH scheduling field indicates that the DCI includes at least one of the short message field or the scheduling field. 
     For example, in one manner, a header composed of N bits (which may use joint coding) is used to indicate which kind of information is carried behind the header: 
     A. Short message. That is, M bits are used to indicate the change of system information. The change of system information includes at least one of the following: whether all system information (referred to as ordinary system information) has changed, whether all system information (including public safety system information) has changed, whether all system information except an MIB has changed, whether all system information except the MIB and SIB  1  has changed, whether per-SIB messages have changed, whether per-SI messages have changed, or whether the public safety system information (CMAS and/or ETWS) has changed. The rest are reserved bits. 
     B. K bits, indicating that the PDSCH scheduling information for the paging message is carried. Further, the scheduling information may carry indication information used for indicating whether the paging message carries a change indication of system information, where K is an integer greater than or equal to 1. 
     C. Both the short message and the paging PDSCH scheduling information are carried. 
     For example, when N=2, as shown in  FIG.  4   , the two bits indicate at least one of the scheduling information or the short message, where a code point 00 is reserved for indicating other cases (case) later. 
     For another example, in another scheme, the N bits in the header field each are used to indicate which kind of information is carried behind the header: 
     A. As shown in  FIG.  5   , one bit indicates whether the short message is present behind the header. 
     B. As shown in  FIG.  5   , one bit indicates whether the PDSCH scheduling information corresponding to the paging message is present behind. 
     In the foregoing two schemes, the locations of the short message (short message) and the PDSCH scheduling information for the paging message (Paging PDSCH scheduling) may alternatively be changed. 
     In another optional implementation, the DCI carries the short message, and the indication information is used to indicate whether the DCI carries the scheduling information. 
     The short message may be M bits, and M is an integer greater than or equal to 1. For details of the short message, reference may be made to the description of the foregoing implementation. Details are not described herein again. 
     The indication information may be one bit. For example, as shown in  FIG.  6   , 1 indicates that the scheduling information is carried, and 0 indicates that the scheduling information is not carried. Certainly, in this embodiment of this disclosure, a quantity of bits of the indication information is not limited. For example, the indication information may be N bits, where N is an integer greater than or equal to 1. 
     It should be noted that, as shown in  FIG.  6   , the indication information may be located after the short message and before the scheduling information. However, in this embodiment of this disclosure, the locations of the short message and the scheduling information are not limited, and a location of the indication information is neither limited. For example, the indication information may be at the last location of the DCI or before the reserved bits. 
     In this implementation, the indication information merely needs to indicate whether the scheduling information is carried, thereby reducing overheads of the DCI. 
     Optionally, in this implementation, the DCI includes K 1  bits. If the indication information indicates that the DCI carries the scheduling information, the K 1  bits are used to indicate the scheduling information. If the indication information indicates that the DCI does not carry the scheduling information, the K 1  bits are reserved bits, where K 1  is an integer greater than or equal to 1. 
     In this way, the reserved bits of the DCI can be used properly to indicate the scheduling information, thereby reducing overheads of the DCI. Furthermore, an effect of lower complexity is achieved because it is not necessary to design new-format DCI. 
     In the foregoing implementation, the header field may be removed, and the DCI includes a short message field+a scheduling indication field and/or a paging PDSCH scheduling field+a reserved field, where the scheduling indication field includes the indication information for indicating whether the DCI carries the scheduling information. 
     In one scheme, the DCI may specifically include: 
     a. M bits used for indicating the change of system information. For details, reference may be made to the M bits described in the foregoing embodiment. 
     b. H 1  bits used for indicating whether the paging PDSCH scheduling information is carried behind, where H 1  may be optionally one bit. 
     c. If it is indicated that the paging PDSCH scheduling information is carried, K bits indicate that the PDSCH scheduling information for the paging message is carried. A code point (code point) of the K bits does not need to be reserved for indicating absence of the scheduling information. If it is indicated that the paging PDSCH scheduling information is not carried, all subsequent bits are reserved bits. 
     In another optional implementation, the DCI includes a header field, the header field includes the indication information, and the indication information is used to indicate that the DCI carries one of the short message and the scheduling information; and if the DCI further carries the other one of the short message and the scheduling information, the other one of the short message and the scheduling information is indicated by using Kx bits in the DCI, where Kx is an integer greater than or equal to 1. 
     In this implementation, the header field may be used to indicate that the DCI carries the short message or the scheduling information. When the DCI carries both the short message and the scheduling information, the Kx bits are used to indicate content not indicated by the header field. In this way, the overheads of the DCI can be reduced because the header field can indicate, by using one bit, whether the DCI carries the short message or the scheduling information. In addition, because other content is not indicated, complexity of the DCI can be further reduced. 
     The following describes four optional implementations by using examples. 
     In an optional implementation, if the indication information indicates that the DCI carries the short message, and the K 2  bits in the DCI are not a specific code point, the K 2  bits are used to indicate the scheduling information. If the K 2  bits are the specific code point, it indicates that the DCI does not carry the scheduling information, where K 2  is an integer greater than or equal to 1. 
     In this implementation, when the indication information indicates that the DCI carries the short message, the K 2  bits may be used to indicate the scheduling information or indicate that the DCI does not carry the scheduling information. The specific code point may be pre-configured, protocol-defined, or configured for the terminal by a network side. For example, the K 2  bits are all 0s. 
     In this implementation, the specific code point is used to indicate whether the scheduling information is carried, and when the K 2  bits are not the specific code point, the K 2  bits are used to indicate the scheduling information, thereby reducing the overheads of the DCI, without the need to use additional bits to indicate whether the scheduling information is carried. 
     In this implementation, the DCI may include a header field+a short message field and/or a paging PDSCH scheduling field+an indication field+a reserved field. It should be noted that the indication field herein represents the K 2  bits when the K 2  bits are the specific code point, and the scheduling field represents the K 2  bits when the K 2  bits are not the specific code point. 
     For example, the DCI may specifically include: 
     a. a header field of N 1  bits, indicating whether the short message or the PDSCH scheduling information for the paging message is carried behind. 
     b. If the short message is carried, c is interpreted as follows: 
     c. In the reserved bits after the short message, K bits are used to indicate that the PDSCH scheduling information for the paging message is carried. One code point (code point) of the K bits is reserved to indicate that the PDSCH scheduling information for the paging message is not carried. For example, the K bits being all 0s are reserved to indicate that the PDSCH scheduling information for the paging message is not carried. 
     In an optional implementation, if the indication information indicates that the DCI carries the short message, the DCI includes a first indication bit, where the first indication bit is used to indicate whether the DCI carries the scheduling information; if the first indication bit indicates that the DCI carries the scheduling information, K 3  bits in the DCI are used to indicate the scheduling information, where K 3  is an integer greater than or equal to 1. 
     In this implementation, the indication information may indicate that the DCI carries the short message, and a first indication bit is used to indicate whether the DCI carries the scheduling information. If the DCI carries the scheduling information, the 
     K 3  bits are used to indicate the scheduling information. The first indication bit may be one bit. For example, 1 indicates that the scheduling information is carried, and 0 indicates that the scheduling information is not carried. Certainly, a quantity of bits and a location of the first indication bit are not limited. 
     In this way, the first indication bit is specially used to indicate whether the DCI carries the scheduling information, thereby reducing complexity of the DCI. 
     In this implementation, the DCI may include: a header field+a short message field and/or a paging PDSCH scheduling field+an indication field+a reserved field. 
     For example, the DCI may specifically include: 
     a. a header field of N 1  bits, indicating whether the short message or the PDSCH scheduling information for the paging message is carried behind, for example, one bit. 
     b. If the short message is carried, c and d are interpreted as follows: 
     c. In the reserved bits after the short message, K bits are used to indicate that the PDSCH scheduling information for the paging message is carried. 
     d. N 2  bits are used after the short message to indicate whether the PDSCH scheduling information for the paging message is carried, where the N 2  bits may be at any location after the short message, for example, N 2 =1 bit. 
     In an optional implementation, if the indication information indicates that the DCI carries the scheduling information, M 1  bits in the DCI are used to indicate the short message, where M 1  is an integer greater than or equal to 1. 
     In this implementation, when the DCI carries the scheduling information and the short message, whether the DCI carries the scheduling information is merely indicated by using the indication information, thereby reducing overheads of the DCI. 
     In this implementation, the DCI may include: a header field+a short message field and/or a paging PDSCH scheduling field+a reserved field. 
     For example, the DCI may specifically include: 
     a. a header field of N 1  bits, indicating whether the short message or the PDSCH scheduling information for the paging message is carried behind. 
     b. If the PDSCH scheduling information for the paging message is carried, c is interpreted as follows: 
     c. In the reserved bits after the scheduling information, M bits are used to indicate an update of system information. 
     In an optional implementation, if the indication information indicates that the DCI carries the scheduling information, the DCI includes a second indication bit, where the second indication bit is used to indicate whether the DCI carries the short message; and if the second indication bit indicates that the DCI carries the short message, M 2  bits in the DCI are used to indicate the short message, where M 2  is an integer greater than or equal to 1. 
     In this implementation, the indication information may indicate that the DCI carries the scheduling information, the second indication bit is used to indicate whether the DCI carries the short message, and if the DCI carries the short message, the M 2  bits are used to indicate the short message. The second indication bit may be one bit. For example, 1 indicates that the short message is carried, and 0 indicates that the short message is not carried. Certainly, a quantity of bits and a location of the second indication bit are not limited. 
     In this way, the second indication bit is specially used to indicate whether the DCI carries the short message, thereby reducing complexity of the DCI. 
     In this implementation, the DCI may include: a header field+a short message field and/or a paging PDSCH scheduling field+an indication field+a reserved field. 
     For example, the DCI may specifically include: 
     a. a header field of N 1  bits, for example, one bit, indicating whether the short message or the PDSCH scheduling information for the paging message is carried behind. 
     b. If the PDSCH scheduling information for the paging message is carried, c and d are interpreted as follows: 
     c. In the reserved bits after the scheduling information, M bits are used to indicate an update of system information. 
     d. H 2  bits are used after the scheduling information to indicate whether an update of the system information is carried. The H 2  bits may be at any location behind the scheduling information, for example, H 2 =1 bit. It should be noted that the H 2  bits herein is the second indication bit. 
     Step  302 : Obtain at least one of the scheduling information or the short message from the DCI. 
     It should be noted that in this embodiment, in some implementations, the DCI may alternatively not include the indication information in step  301 . 
     For example, in an optional implementation, the DCI carries the short message, and the DCI further includes K 4  bits; if the K 4  bits are not a specific code point, the K 4  bits are used to indicate the scheduling information; and if the K 4  bits are the specific code point, it indicates that the DCI does not carry the scheduling information, where K 4  is an integer greater than or equal to 1. 
     In this implementation, when the DCI carries the short message, K 4  bits are used to indicate the scheduling information, and the K 4  bits are the specific code point, indicating that the DCI does not carry the scheduling information, thereby reducing overheads of the DCI. The specific code point may be pre-configured by the terminal, predefined in the protocol, or pre-configured for the terminal by the network side. For example, the K 4  bits are all 0s. 
     In this implementation, the header field may be removed and the DCI includes a short message field and/or a paging PDSCH scheduling field+a reserved field, for example, as shown in  FIG.  7   . 
     In one scheme, the DCI may specifically include: 
     a. M bits, used for indicating the change of system information. For the M bits herein, reference may be made to the description of the foregoing implementation. Details are not described herein again. 
     B. K bits, indicating that the PDSCH scheduling information for the paging message is carried. One code point (code point) of the K bits is reserved to indicate that the PDSCH scheduling information for carrying the paging message is not present behind. For example, the K bits being all 0s are used to indicate that the PDSCH scheduling information for the paging message is not carried. 
     It should be noted that, in this embodiment of this disclosure, K, K 1 , K 2 , K 3 , K 4 , and Kx may be the same value or certainly may be different values, which is not limited. Similarly, M 1  and M 2  may be the same value or certainly may be different values, which is not limited. 
     Optionally, in this embodiment of this disclosure, remaining bits in the DCI are reserved bits (Reserved bits). The remaining bits herein may be bits not defined in the DCI in this embodiment of this disclosure, for example, the reserved (Reserved) field shown in  FIG.  4    to  FIG.  7   . 
     Optionally, in this embodiment of this disclosure, the scheduling information or the DCI carries indication information, and the indication information is used to indicate whether the paging message carries a change indication of system information. 
     Because the scheduling information or the DCI may indicate whether the paging message carries the change indication of system information, the terminal can quickly determine whether the paging message carries the change indication of system information, thereby improving working efficiency of the terminal and reducing a delay. 
     In this embodiment of this disclosure, a plurality of optional implementations are added on a basis of the embodiment shown in  FIG.  1   . In addition, signaling transmission overheads can be reduced, and the following beneficial effects can be achieved: a delay for obtaining the update indication of system information by the idle-state terminal and the connected-state terminal can be reduced, and a delay for paging the idle-state terminal can be reduced. It can be implemented that the DCI includes but is not limited to the following DCI formats:
         a header field+a short message and/or a paging PDSCH scheduling field;   a short message field and/or a paging PDSCH scheduling field+a reserved field;   a short message field+a scheduling indication field and/or a paging PDSCH scheduling field+a reserved field; and   a header+a short message field and/or a paging PDSCH scheduling field+an indication field+a reserved field.       

     The short message and/or the paging PDSCH scheduling field indicates that the DCI includes at least one of the short message or the paging PDSCH scheduling field. 
     Referring to  FIG.  8   ,  FIG.  8    is a flowchart of another DCI transmission method according to an embodiment of this disclosure. The method is applied to a base station, and as shown in  FIG.  8   , includes the following steps. 
     Step  801 : Generate DCI, where when there is simultaneously in a network a paging message for an idle-state terminal and a change of system information, the DCI carries PDSCH scheduling information for the paging message and a short message; otherwise, the DCI carries the scheduling information or the short message, where the short message is used to indicate the change of system information. 
     Step  802 : Transmit the DCI on a PDCCH. 
     Optionally, the DCI further includes indication information, and the indication information is used to indicate content carried in the DCI. 
     Optionally, the DCI includes a header field, and the header field includes the indication information. 
     The indication information indicates that the DCI carries at least one of the scheduling information or the short message; or 
     a portion of bits in the indication information is used to indicate whether the DCI carries the scheduling information, and the other portion of bits is used to indicate whether the DCI carries the short message. 
     Optionally, the DCI carries the short message, and the indication information is used to indicate whether the DCI carries the scheduling information. 
     Optionally, the DCI includes K 1  bits; and if the indication information indicates that the DCI carries the scheduling information, the K 1  bits are used to indicate the scheduling information; or if the indication information indicates that the DCI does not carry the scheduling information, the K 1  bits are reserved bits, where K 1  is an integer greater than or equal to 1. 
     Optionally, the DCI includes a header field, the header field includes the indication information, and the indication information is used to indicate that the DCI carries one of the short message and the scheduling information; and if the DCI further carries the other one of the short message and the scheduling information, the other one of the short message and the scheduling information is indicated by using Kx bits in the DCI, where Kx is an integer greater than or equal to 1. 
     Optionally, if the indication information indicates that the DCI carries the short message, and K 2  bits in the DCI are not a specific code point, the K 2  bits are used to indicate the scheduling information; and if the K 2  bits are the specific code point, it indicates that the DCI does not carry the scheduling information, where K 2  is an integer greater than or equal to 1; or 
     if the indication information indicates that the DCI carries the short message, the DCI includes a first indication bit, where the first indication bit is used to indicate whether the DCI carries the scheduling information; if the first indication bit indicates that the DCI carries the scheduling information, K 3  bits in the DCI are used to indicate the scheduling information, where K 3  is an integer greater than or equal to 1; or 
     if the indication information indicates that the DCI carries the scheduling information, M 1  bits in the DCI are used to indicate the short message, where M 1  is an integer greater than or equal to 1; or 
     if the indication information indicates that the DCI carries the scheduling information, the DCI includes a second indication bit, where the second indication bit is used to indicate whether the DCI carries the short message; and if the second indication bit indicates that the DCI carries the short message, M 2  bits in the DCI are used to indicate the short message, where M 2  is an integer greater than or equal to 1. 
     Optionally, the DCI carries the short message, and the DCI further includes K 4  bits; if the K 4  bits are not a specific code point, the K 4  bits are used to indicate the scheduling information; and if the K 4  bits are the specific code point, it indicates that the DCI does not carry the scheduling information, where K 4  is an integer greater than or equal to 1. 
     Optionally, the remaining bits in the DCI are reserved bits. 
     Optionally, the change of system information includes at least one of a change of ordinary system information or a change of public safety system information. 
     If there are remaining bits in the short message, the remaining bits are reserved bits. 
     Optionally, the scheduling information or the DCI carries indication information, and the indication information is used to indicate whether the paging message carries a change indication of system information. 
     It should be noted that this embodiment is used as an implementation of the base station corresponding to the embodiments shown in  FIG.  2    and  FIG.  3   . For a specific implementation of this embodiment, reference may be made to the related descriptions of the embodiments shown in  FIG.  2    and  FIG.  3   , and a same beneficial effect is achieved. To avoid repetition, details are not described herein again. 
     Referring to  FIG.  9   ,  FIG.  9    is a structural diagram of a terminal according to an embodiment of this disclosure. As shown in  FIG.  9   , the terminal  900  includes: 
     a receiving module  901 , configured to receive DCI, where when there is simultaneously in a network a paging message for an idle-state terminal and a change of system information, the DCI carries PDSCH scheduling information for the paging message and a short message; otherwise, the DCI carries the scheduling information or the short message, where the short message is used to indicate the change of system information; and 
     an obtaining module  902 , configured to obtain at least one of the scheduling information or the short message from the DCI. 
     Optionally, the DCI further includes indication information, and the indication information is used to indicate content carried in the DCI. 
     Optionally, the DCI includes a header field, and the header field includes the indication information. 
     The indication information indicates that the DCI carries at least one of the scheduling information or the short message; or 
     a portion of bits in the indication information is used to indicate whether the DCI carries the scheduling information, and the other portion of bits is used to indicate whether the DCI carries the short message. 
     Optionally, the DCI carries the short message, and the indication information is used to indicate whether the DCI carries the scheduling information. 
     Optionally, the DCI includes K 1  bits; and if the indication information indicates that the DCI carries the scheduling information, the K 1  bits are used to indicate the scheduling information; or if the indication information indicates that the DCI does not carry the scheduling information, the K 1  bits are reserved bits, where K 1  is an integer greater than or equal to 1. 
     Optionally, the DCI includes a header field, the header field includes the indication information, and the indication information is used to indicate that the DCI carries one of the short message and the scheduling information; and if the DCI further carries the other one of the short message and the scheduling information, the other one of the short message and the scheduling information is indicated by using Kx bits in the DCI, where Kx is an integer greater than or equal to 1. 
     Optionally, if the indication information indicates that the DCI carries the short message, and K 2  bits in the DCI are not a specific code point, the K 2  bits are used to indicate the scheduling information; and if the K 2  bits are the specific code point, it indicates that the DCI does not carry the scheduling information, where K 2  is an integer greater than or equal to 1; or 
     if the indication information indicates that the DCI carries the short message, the DCI includes a first indication bit, where the first indication bit is used to indicate whether the DCI carries the scheduling information; if the first indication bit indicates that the DCI carries the scheduling information, K 3  bits in the DCI are used to indicate the scheduling information, where K 3  is an integer greater than or equal to 1; or 
     if the indication information indicates that the DCI carries the scheduling information, M 1  bits in the DCI are used to indicate the short message, where M 1  is an integer greater than or equal to 1; or 
     if the indication information indicates that the DCI carries the scheduling information, the DCI includes a second indication bit, where the second indication bit is used to indicate whether the DCI carries the short message; and if the second indication bit indicates that the DCI carries the short message, M 2  bits in the DCI are used to indicate the short message, where M 2  is an integer greater than or equal to 1. 
     Optionally, the DCI carries the short message, and the DCI further includes K 4  bits; if the K 4  bits are not a specific code point, the K 4  bits are used to indicate the scheduling information; and if the K 4  bits are the specific code point, it indicates that the DCI does not carry the scheduling information, where K 4  is an integer greater than or equal to 1. 
     Optionally, the remaining bits in the DCI are reserved bits. 
     Optionally, the change of system information includes at least one of a change of ordinary system information or a change of public safety system information. 
     If there are remaining bits in the short message, the remaining bits are reserved bits. 
     Optionally, the scheduling information or the DCI carries indication information, and the indication information is used to indicate whether the paging message carries a change indication of system information. 
     The terminal provided in this embodiment of this disclosure can implement various processes implemented by the terminal in the method embodiments of  FIG.  2    and  FIG.  3   . To avoid repetition, details are not described herein again. Signaling transmission overheads can be reduced, and the following effects can be achieved: a delay for obtaining an update indication of system information by the idle-state terminal and the connected-state terminal can be reduced, and a delay for paging the idle-state terminal can be further reduced. 
     Referring to  FIG.  10   ,  FIG.  10    is a structural diagram of a base station according to an embodiment of this disclosure. As shown in  FIG.  10   , the base station  1000  includes: 
     a generation module  1001 , configured to generate DCI, where when there is simultaneously in a network a paging message for an idle-state terminal and a change of system information, the DCI carries PDSCH scheduling information for the paging message and a short message; otherwise, the DCI carries the scheduling information or the short message, where the short message is used to indicate the change of system information; and 
     a transmission module  1002 , configured to transmit the DCI on a PDCCH. 
     Optionally, the DCI further includes indication information, and the indication information is used to indicate content carried in the DCI. 
     Optionally, the DCI includes a header field, and the header field includes the indication information. 
     The indication information indicates that the DCI carries at least one of the scheduling information or the short message; or 
     a portion of bits in the indication information is used to indicate whether the DCI carries the scheduling information, and the other portion of bits is used to indicate whether the DCI carries the short message. 
     Optionally, the DCI carries the short message, and the indication information is used to indicate whether the DCI carries the scheduling information. 
     Optionally, the DCI includes K 1  bits; and if the indication information indicates that the DCI carries the scheduling information, the K 1  bits are used to indicate the scheduling information; or if the indication information indicates that the DCI does not carry the scheduling information, the K 1  bits are reserved bits, where K 1  is an integer greater than or equal to 1. 
     Optionally, the DCI includes a header field, the header field includes the indication information, and the indication information is used to indicate that the DCI carries one of the short message and the scheduling information; and if the DCI further carries the other one of the short message and the scheduling information, the other one of the short message and the scheduling information is indicated by using Kx bits in the DCI, where Kx is an integer greater than or equal to 1. 
     Optionally, if the indication information indicates that the DCI carries the short message, and K 2  bits in the DCI are not a specific code point, the K 2  bits are used to indicate the scheduling information; and if the K 2  bits are the specific code point, it indicates that the DCI does not carry the scheduling information, where K 2  is an integer greater than or equal to 1; or 
     if the indication information indicates that the DCI carries the short message, the DCI includes a first indication bit, where the first indication bit is used to indicate whether the DCI carries the scheduling information; if the first indication bit indicates that the DCI carries the scheduling information, K 3  bits in the DCI are used to indicate the scheduling information, where K 3  is an integer greater than or equal to 1; or 
     if the indication information indicates that the DCI carries the scheduling information, M 1  bits in the DCI are used to indicate the short message, where M 1  is an integer greater than or equal to 1; or 
     if the indication information indicates that the DCI carries the scheduling information, the DCI includes a second indication bit, where the second indication bit is used to indicate whether the DCI carries the short message; and if the second indication bit indicates that the DCI carries the short message, M 2  bits in the DCI are used to indicate the short message, where M 2  is an integer greater than or equal to 1. 
     Optionally, the DCI carries the short message, and the DCI further includes K 4  bits; if the K 4  bits are not a specific code point, the K 4  bits are used to indicate the scheduling information; and if the K 4  bits are the specific code point, it indicates that the DCI does not carry the scheduling information, where K 4  is an integer greater than or equal to 1. 
     Optionally, the remaining bits in the DCI are reserved bits. 
     Optionally, the change of system information includes at least one of a change of ordinary system information or a change of public safety system information. 
     If there are remaining bits in the short message, the remaining bits are reserved bits. 
     Optionally, the scheduling information or the DCI carries indication information, and the indication information is used to indicate whether the paging message carries a change indication of system information. 
     The base station provided in this embodiment of this disclosure can implement various processes implemented by the base station in the method embodiment of  FIG.  8   . To avoid repetition, details are not described herein again. Signaling transmission overheads can be reduced, and the following effects can be achieved: a delay for obtaining an update indication of system information by the idle-state terminal and the connected-state terminal can be reduced, and a delay for paging the idle-state terminal can be further reduced. 
       FIG.  11    is a schematic diagram of a hardware structure of a terminal for implementing the embodiments of this disclosure. 
     The terminal  1100  includes but is not limited to components such as a radio frequency unit  1101 , a network module  1102 , an audio output unit  1103 , an input unit  1104 , a sensor  1105 , a display unit  1106 , a user input unit  1107 , an interface unit  1108 , a memory  1109 , a processor  1110 , and a power supply  1111 . Persons skilled in the art can understand that a structure of the terminal shown in  FIG.  11    does not constitute any limitation on the terminal, and the terminal may include more or fewer components than those shown in the figure, or a combination of some of the components, or a different arrangement of the components. In this embodiment of this disclosure, the terminal includes but is not limited to a mobile phone, a tablet computer, a laptop computer, a palmtop computer, an in-vehicle terminal, a wearable device, a pedometer, and the like. 
     The radio frequency unit  1101  is configured to receive DCI, where when there is simultaneously in a network a paging message for an idle-state terminal and a change of system information, the DCI carries PDSCH scheduling information for the paging message and a short message; otherwise, the DCI carries the scheduling information or the short message, where the short message is used to indicate the change of system information. 
     The processor  1110  is configured to obtain at least one of the scheduling information or the short message from the DCI. 
     Optionally, the DCI further includes indication information, and the indication information is used to indicate content carried in the DCI. 
     Optionally, the DCI includes a header field, and the header field includes the indication information. 
     The indication information indicates that the DCI carries at least one of the scheduling information or the short message; or 
     a portion of bits in the indication information is used to indicate whether the DCI carries the scheduling information, and the other portion of bits is used to indicate whether the DCI carries the short message. 
     Optionally, the DCI carries the short message, and the indication information is used to indicate whether the DCI carries the scheduling information. 
     Optionally, the DCI includes K 1  bits; and if the indication information indicates that the DCI carries the scheduling information, the K 1  bits are used to indicate the scheduling information; or if the indication information indicates that the DCI does not carry the scheduling information, the K 1  bits are reserved bits, where K 1  is an integer greater than or equal to 1. 
     Optionally, the DCI includes a header field, the header field includes the indication information, and the indication information is used to indicate that the DCI carries one of the short message and the scheduling information; and if the DCI further carries the other one of the short message and the scheduling information, the other one of the short message and the scheduling information is indicated by using Kx bits in the DCI, where Kx is an integer greater than or equal to 1. 
     Optionally, if the indication information indicates that the DCI carries the short message, and K 2  bits in the DCI are not a specific code point, the K 2  bits are used to indicate the scheduling information; and if the K 2  bits are the specific code point, it indicates that the DCI does not carry the scheduling information, where K 2  is an integer greater than or equal to 1; or 
     if the indication information indicates that the DCI carries the short message, the DCI includes a first indication bit, where the first indication bit is used to indicate whether the DCI carries the scheduling information; if the first indication bit indicates that the DCI carries the scheduling information, K 3  bits in the DCI are used to indicate the scheduling information, where K 3  is an integer greater than or equal to 1; or 
     if the indication information indicates that the DCI carries the scheduling information, M 1  bits in the DCI are used to indicate the short message, where M 1  is an integer greater than or equal to 1; or 
     if the indication information indicates that the DCI carries the scheduling information, the DCI includes a second indication bit, where the second indication bit is used to indicate whether the DCI carries the short message; and if the second indication bit indicates that the DCI carries the short message, M 2  bits in the DCI are used to indicate the short message, where M 2  is an integer greater than or equal to 1. 
     Optionally, the DCI carries the short message, and the DCI further includes K 4  bits; if the K 4  bits are not a specific code point, the K 4  bits are used to indicate the scheduling information; and if the K 4  bits are the specific code point, it indicates that the DCI does not carry the scheduling information, where K 4  is an integer greater than or equal to 1. 
     Optionally, the remaining bits in the DCI are reserved bits. 
     Optionally, the change of system information includes at least one of a change of ordinary system information or a change of public safety system information; 
     If there are remaining bits in the short message, the remaining bits are reserved bits. 
     Optionally, the scheduling information or the DCI carries indication information, and the indication information is used to indicate whether the paging message carries a change indication of system information. 
     The foregoing terminal can reduce signaling transmission overheads, and can also achieve the effects of reducing a delay for obtaining an update indication of system information by the idle-state terminal and the connected-state terminal, and further reducing a delay for paging the idle-state terminal. 
     It should be understood that in an embodiment of this disclosure, the radio frequency unit  1101  may be configured to: receive and send signals in an information receiving/sending process or a call process; and specifically, after receiving downlink data from a base station, send the downlink information to the processor  1110  for processing, and in addition, send uplink data to the base station. Usually, the radio frequency unit  1101  includes but is not limited to an antenna, at least one amplifier, a transceiver, a coupler, a low noise amplifier, a duplexer, and the like. In addition, the radio frequency unit  1101  may further communicate with a network and another device through a wireless communications system. 
     The terminal provides a user with wireless broadband internet access through the network module  1102 , for example, helping the user to send or receive an e-mail, to browse a web page, or to access streaming media. 
     The audio output unit  1103  may convert audio data received by the radio frequency unit  1101  or the network module  1102  or stored in the memory  1109  into an audio signal and output the audio signal as a sound. The audio output unit  1103  may also provide audio output (for example, a call signal received sound or a message received sound) related to a specific function performed by the terminal  1100 . The audio output unit  1103  includes a speaker, a buzzer, a receiver, and the like. 
     The input unit  1104  is configured to receive an audio or video signal. The input unit  1104  may include a graphics processing unit (Graphics Processing Unit, GPU)  11041  and a microphone  11042 , and the graphics processing unit  11041  processes image data of a still picture or a video obtained by an image capture apparatus (for example, a camera) in an image capture mode or a video capture mode. A processed image frame may be displayed on the display unit  1106 . An image frame processed by the graphics processing unit  11041  may be stored in the memory  1109  (or other storage media) or sent by the radio frequency unit  1101  or the network module  1102 . The microphone  11042  can receive a sound and can process the sound into audio data. The processed audio data can be converted into a format that can be sent to a mobile communication base station through the radio frequency unit  601  in a telephone call mode, for outputting. 
     The terminal  1100  may further include at least one sensor  1105  such as a light sensor, a motion sensor, and other sensors. Specifically, the light sensor includes an ambient light sensor and a proximity sensor, where the ambient light sensor can adjust luminance of a display panel  11061  based on brightness of ambient light, and the proximity sensor can turn off the display panel  11061  and/or backlight when the terminal  1100  is moved to an ear. As a type of motion sensor, an accelerometer sensor can detect magnitudes of accelerations in all directions (usually three axes), can detect a magnitude and a direction of gravity when the mobile phone is in a static state, and can be applied to terminal posture recognition (such as screen switching between portrait and landscape, related games, and magnetometer posture calibration), functions related to vibration recognition (such as pedometer and tapping), and the like. The sensor  1105  may also include a fingerprint sensor, a pressure sensor, an iris sensor, a molecular sensor, a gyroscope, a barometer, a hygrometer, a thermometer, an infrared sensor, and the like. Details are not described herein. 
     The display unit  1106  is configured to display information input by the user or information provided for the user. The display unit  1106  may include a display panel  11061 , and the display panel  11061  may be configured in a form of a liquid crystal display (Liquid Crystal Display, LCD), an organic light-emitting diode (Organic Light-Emitting Diode, OLED), or the like. 
     The user input unit  1107  may be configured to receive input digital or character information and generate key signal input related to user setting and function control of the terminal. Specifically, the user input unit  1107  may include a touch panel  11071  and other input devices  11072 . The touch panel  11071 , also referred to as a touchscreen, may capture a touch operation performed by a user on or near the touch panel (for example, an operation performed by the user on the touch panel  11071  or near the touch panel  11071  by using any appropriate object or accessory such as a finger or a stylus). The touch panel  11071  may include two parts: a touch detection apparatus and a touch controller. The touch detection apparatus detects a touch direction of the user, detects a signal carried by a touch operation, and transmits the signal to the touch controller. The touch controller receives touch information from the touch detection apparatus, converts the touch information to point coordinates, and sends the point coordinates to the processor  1110 , and receives and executes a command sent by the processor  1110 . In addition, the touch panel  11071  may be implemented in a plurality of forms, for example, as a resistive, capacitive, infrared, or surface acoustic wave touch panel. The user input unit  1107  may further include other input devices  11072  in addition to the touch panel  11071 . Specifically, the other input devices  11072  may include but are not limited to a physical keyboard, a function key (such as a volume control key or a power on/off key), a trackball, a mouse, and a joystick. Details are not described herein. 
     Further, the touch panel  11071  may cover the display panel  11061 . After detecting a touch operation on or near the touch panel  11071 , the touch panel  6071  transmits information about the touch operation to the processor  1110  for the processor  1110  to determine a touch event type, and then the processor  610  provides a corresponding visual output on the display panel  11061  based on the touch event type. Although in  FIG.  11   , the touch panel  11071  and the display panel  11061  act as two independent parts to implement input and output functions of the terminal, in some embodiments, the touch panel  11071  and the display panel  11061  may be integrated to implement the input and output functions of the terminal. This is not specifically limited herein. 
     The interface unit  1108  is an interface between an external apparatus and the terminal  1100 . For example, the external apparatus may include a wired or wireless headphone port, an external power (or battery charger) port, a wired or wireless data port, a memory card port, a port for connecting an apparatus provided with a recognition module, an audio input/output (I/O) port, a video I/O port, an earphone port, and the like. The interface unit  1108  may be configured to: receive input (for example, data information and power) from the external apparatus, and transmit the received input to one or more elements in the terminal  1100 , or may be configured to transmit data between the terminal  1100  and the external apparatus. 
     The memory  1109  may be configured to store a software program and various data. The memory  1109  may mainly include a program storage area and a data storage area. The program storage area may store an operating system, an application program required for at least one function (such as a sound play function and an image play function), and the like. The data storage area may store data created based on use of the mobile phone (such as audio data and a phone book), and the like. In addition, the memory  1109  may include a high-speed random access memory, or may include a non-volatile memory, for example, at least one magnetic disk storage device, a flash memory device, or other volatile solid-state storage devices. 
     The processor  1110  is a control center of the terminal, and is configured to: connect various parts of the entire terminal by using various interfaces or lines, and perform various functions of the terminal and process data by running or executing software programs and/or modules stored in the memory  1109  and calling data stored in the memory  1109 , so as to perform overall monitoring on the terminal. The processor  1110  may include one or more processing units. Optionally, an application processor and a modem processor may be integrated into the processor  1110 . The application processor mainly processes an operating system, a user interface, an application program, and the like. The modem processor mainly processes wireless communication. It can be understood that the modem processor may alternatively not be integrated in the processor  1110 . 
     The terminal  1100  may further include the power supply  1111  (such as a battery) for supplying power to all components. Optionally, the power supply  1111  may be logically connected to the processor  1110  through a power management system. In this way, functions such as charge management, discharge management, and power consumption management are implemented by using the power management system. 
     In addition, the terminal  1100  includes some functional modules that are not shown, details of which are not described herein. 
     Optionally, an embodiment of this disclosure further provides a terminal, including a processor  1110 , a memory  1109 , a computer program stored in the memory  1109  and capable of running on the processor  1110 . When the computer program is executed by the processor  1110 , the processes of the DCI transmission method embodiment are implemented, with the same technical effect achieved. To avoid repetition, details are not described herein again. 
     Referring to  FIG.  12   ,  FIG.  12    is a structural diagram of another base station according to an embodiment of this disclosure. As shown in  FIG.  12   , the base station  1200  includes a processor  1201 , a transceiver  1202 , a memory  1203 , and a bus interface. 
     The processor  1201  is configured to generate DCI, where when there is simultaneously in a network a paging message for an idle-state terminal and a change of system information, the DCI carries PDSCH scheduling information for the paging message and a short message; otherwise, the DCI carries the scheduling information or the short message, where the short message is used to indicate the change of system information. 
     The transceiver  1202  is configured to transmit the DCI on a PDCCH. 
     Optionally, the DCI further includes indication information, and the indication information is used to indicate content carried in the DCI. 
     Optionally, the DCI includes a header field, and the header field includes the indication information. 
     The indication information indicates that the DCI carries at least one of the scheduling information or the short message; or 
     a portion of bits in the indication information is used to indicate whether the DCI carries the scheduling information, and the other portion of bits is used to indicate whether the DCI carries the short message. 
     Optionally, the DCI carries the short message, and the indication information is used to indicate whether the DCI carries the scheduling information. 
     Optionally, the DCI includes K 1  bits; and if the indication information indicates that the DCI carries the scheduling information, the K 1  bits are used to indicate the scheduling information; or if the indication information indicates that the DCI does not carry the scheduling information, the K 1  bits are reserved bits, where K 1  is an integer greater than or equal to 1. 
     Optionally, the DCI includes a header field, the header field includes the indication information, and the indication information is used to indicate that the DCI carries one of the short message and the scheduling information; and if the DCI further carries the other one of the short message and the scheduling information, the other one of the short message and the scheduling information is indicated by using Kx bits in the DCI, where Kx is an integer greater than or equal to 1. 
     Optionally, if the indication information indicates that the DCI carries the short message, and K 2  bits in the DCI are not a specific code point, the K 2  bits are used to indicate the scheduling information; and if the K 2  bits are the specific code point, it indicates that the DCI does not carry the scheduling information, where K 2  is an integer greater than or equal to 1; or 
     if the indication information indicates that the DCI carries the short message, the DCI includes a first indication bit, where the first indication bit is used to indicate whether the DCI carries the scheduling information; if the first indication bit indicates that the DCI carries the scheduling information, K 3  bits in the DCI are used to indicate the scheduling information, where K 3  is an integer greater than or equal to 1; or 
     if the indication information indicates that the DCI carries the scheduling information, M 1  bits in the DCI are used to indicate the short message, where M 1  is an integer greater than or equal to 1; or 
     if the indication information indicates that the DCI carries the scheduling information, the DCI includes a second indication bit, where the second indication bit is used to indicate whether the DCI carries the short message; and if the second indication bit indicates that the DCI carries the short message, M 2  bits in the DCI are used to indicate the short message, where M 2  is an integer greater than or equal to 1. 
     Optionally, the DCI carries the short message, and the DCI further includes K 4  bits; if the K 4  bits are not a specific code point, the K 4  bits are used to indicate the scheduling information; and if the K 4  bits are the specific code point, it indicates that the DCI does not carry the scheduling information, where K 4  is an integer greater than or equal to 1. 
     Optionally, the remaining bits in the DCI are reserved bits. 
     Optionally, the change of system information includes at least one of a change of ordinary system information or a change of public safety system information; 
     If there are remaining bits in the short message, the remaining bits are reserved bits. 
     Optionally, the scheduling information or the DCI carries indication information, and the indication information is used to indicate whether the paging message carries a change indication of system information. 
     The foregoing base station can reduce signaling transmission overheads, and can also achieve the effects of reducing a delay for obtaining an update indication of system information by the idle-state terminal and the connected-state terminal, and further reducing a delay for paging the idle-state terminal. 
     The transceiver  1202  is configured to receive and send data under control of the processor  1201 . The transceiver  1202  includes at least two antenna ports. 
     In  FIG.  12   , a bus architecture may include any quantity of interconnected buses and bridges, and specifically connect together various circuits of one or more processors represented by the processor  1201  and a memory represented by the memory  1203 . The bus architecture may further connect, for example, a peripheral device or a voltage stabilizer to various other circuits such as a power management circuit. These are well known in the art, and therefore are not further described in this specification. A bus interface provides an interface. The transceiver  1202  may be a plurality of elements, including a transmitter and a receiver, and provides units configured to perform communication with various other apparatuses over a transmission medium. For different user equipment, a user interface may also be an interface that can be externally or internally connected to a required device. The connected device includes but is not limited to a keypad, a display, a speaker, a microphone, a joystick, and so on. 
     The processor  1201  is responsible for management of the bus architecture and general processing, and the memory  1203  may store data used by the processor  1201  when the processor  610  performs an operation. 
     Optionally, an embodiment of this disclosure further provides a base station, including a processor  1201 , a memory  1203 , a computer program stored in the memory  1203  and capable of running on the processor  1201 . When the computer program is executed by the processor  1201 , the processes of the DCI transmission method embodiment are implemented, with the same technical effect achieved. To avoid repetition, details are not described herein again. 
     An embodiment of this disclosure further provides a computer-readable storage medium. The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the processes of the DCI transmission method on a terminal side provided in the embodiments of this disclosure are implemented, or when the computer program is executed by a processor, the processes of the DCI transmission method on a base station side provided in the embodiments of this disclosure are implemented, with the same technical effect achieved. To avoid repetition, details are not described herein again. The computer-readable storage medium is, for example, a read-only memory (Read-Only Memory, ROM), a random access memory (Random Access Memory, RAM), a magnetic disk, or an optical disc. 
     It should be noted that the terms “include”, “comprise”, or any of their variants are intended to cover a non-exclusive inclusion, such that a process, a method, an article, or an apparatus that includes a list of elements not only includes those elements but also includes other elements that are not expressly listed, or further includes elements inherent to such process, method, article, or apparatus. In absence of more constraints, an element preceded by “includes a . . . ” does not preclude the existence of other identical elements in the process, method, article, or apparatus that includes the element. 
     According to the description of the foregoing implementations, a person skilled in the art can clearly understand that the method in the foregoing embodiments may be implemented by software on a necessary universal hardware platform or by hardware only. In most cases, the former is a more preferred implementation. Based on such an understanding, the technical solutions of this disclosure essentially, or the part contributing to the related art may be implemented in a form of a software product. The software product is stored in a storage medium (for example, a ROM/RAM, a magnetic disk, or an optical disc), and includes several instructions for instructing a terminal (which may be a mobile phone, a computer, a server, an air conditioner, a network device, or the like) to perform the method described in the embodiments of this disclosure. 
     The embodiments of this disclosure are described above with reference to the accompanying drawings, but this disclosure is not limited to the foregoing implementations. The foregoing implementations are only illustrative rather than restrictive. Inspired by this disclosure, a person of ordinary skill in the art can still derive many variations without departing from the essence of this disclosure and the protection scope of the claims. All these variations shall fall within the protection of this disclosure.