Patent Publication Number: US-2021195527-A1

Title: Discontinuous Reception Method, Terminal Device and Network Device

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a 371 application of International Application No. PCT/CN2017/099154, filed on Aug. 25, 2017, the entire disclosure of which is hereby incorporated by reference. 
    
    
     TECHNICAL FIELD 
     Implementations of the present application relate to the field of wireless communication, and more particularly, relate to a discontinuous reception method, a terminal device, and a network device. 
     BACKGROUND 
     Discontinuous Reception (DRX) mechanism is introduced for the sake of power saving of a terminal device. Each DRX Cycle includes an on-duration and an Opportunity for DRX. When in the on-duration, the terminal device detects a control channel. When in the Opportunity for DRX, the terminal device can reduce power consumption by stopping receiving the control channel (in this case, the terminal device stops the blind detection of the control channel), thus prolonging battery life. 
     Although the network configures the terminal device with the DRX mechanism so that the terminal device periodically detects the control channel during the on-duration, the terminal device is scheduled only by chance during the on-duration. Even when the service load is very low, the terminal device will be scheduled only in a few DRX cycles. For a paging message using the DRX mechanism, the terminal has less chance to receive the paging message. Therefore, after being configured with the DRX mechanism, the terminal device may not be able to detect the control channel during most on-durations, but it will still be woken up, which increases unnecessary power consumption. Therefore, how different terminal devices know whether they are scheduled in the DRX cycle to further reduce power consumption has become an urgent problem to be solved. 
     SUMMARY 
     Implementations of the present application provide a discontinuous reception method, a terminal device and a network device. 
     In a first aspect, a discontinuous reception method is provided. The method includes: detecting, by a first terminal device, a downlink control channel sent by a network device, wherein the downlink control channel carries at least one piece of discontinuous reception (DRX) information of at least one terminal device, and DRX information of each terminal device of the at least one terminal device is used for indicating that the each terminal device wakes up or sleeps during an on-duration of a DRX cycle after the DRX information of the each terminal device; determining, by the first terminal device, DRX information of the first terminal device from the at least one piece of DRX information; and waking up or sleeping, by the first terminal device, during the on-duration according to the DRX information of the first terminal device. 
     Therefore, a network device simultaneously indicates multiple pieces of DRX information of multiple terminal devices to the multiple terminal devices, and a first terminal device of the multiple terminal devices determines its own DRX information among the multiple pieces of DRX information and wakes up or sleeps during an on-duration of a subsequent DRX cycle according to its own DRX information. Since the first terminal device can sleep during the on-duration of the DRX cycle when it is not scheduled in the subsequent DRX cycle, the power consumption of the first terminal device is further reduced. 
     In one possible implementation, the downlink control channel carries at least one bit value, the at least one bit value corresponds to the at least one piece of DRX information one by one, and each bit value in the at least one bit value is used for representing DRX information corresponding to the each bit value. 
     In one possible implementation, before the first terminal device detects the downlink control channel sent by the network device, the method further includes: determining, by the first terminal device, a control channel group to which the downlink control channel belongs according to a device identity of the first terminal device; and determining, by the first terminal device, a target radio network temporary identity (RNTI) corresponding to the control channel group according to a mapping relationship between multiple control channel groups and multiple RNTIs; wherein detecting, by the first terminal device, the downlink control channel sent by the network device includes: detecting, by the first terminal device, the downlink control channel according to the target RNTI. 
     For example, the first terminal device calculates a number of the control channel group in which the downlink control channel is located according to the device Identity (ID) of the first terminal device, such as UE-ID, and based on UE-ID mod M. M is a positive integer and M is the total quantity of control channel groups. The first terminal device determines an RNTI used for detecting the downlink control channel according to the calculated number of the control channel group and the mapping relationship between M control channel groups and M RNTIs, and detects the downlink control channel according to the target RNTI. 
     Optionally, the mapping relationship between multiple control channel groups and multiple RNTIs may be notified by the network device through a radio resource control (RRC) signaling to the terminal device, or the mapping relationship may be pre-agreed between the terminal device and the network device and pre-stored in the terminal device. 
     In one possible implementation, before the first terminal device detects the downlink control channel sent by the network device, the method further includes: receiving, by the first terminal device, first configuration information sent by the network device, wherein the first configuration information indicates a target RNTI used for detecting the downlink control channel; wherein detecting, by the first terminal device, the downlink control channel sent by the network device includes: detecting, by the first terminal device, the downlink control channel according to the target RNTI. 
     In one possible implementation, before the first terminal device detects the downlink control channel sent by the network device, the method further includes: receiving, by the first terminal device, second configuration information sent by the network device, wherein the second configuration information is used for indicating a channel format of the downlink control channel; wherein detecting, by the first terminal device, the downlink control channel sent by the network device includes: detecting, by the first terminal device, the downlink control channel according to the channel format of the downlink control channel. 
     In one possible implementation, detecting, by the first terminal device, the downlink control channel sent by the network device includes: detecting, by the first terminal device, the downlink control channel sent by the network device before the DRX cycle; or detecting, by the first terminal device, the downlink control channel sent by the network device in a first subframe or a first slot during the on-duration of the DRX cycle; or detecting, by the first terminal device, the downlink control channel sent by the network device in a common search space of a control channel. 
     In one possible implementation, determining, by the first terminal device, the DRX information of the first terminal device from the at least one piece of DRX information includes: determining, by the first terminal device, the DRX information of the first terminal device according to a number of the first terminal device, wherein the DRX information of the first terminal device is DRX information corresponding to the number in the at least one piece of DRX information. 
     In one possible implementation, before the first terminal device determines the DRX information of the first terminal device according to the number of the first terminal device, the method further includes: receiving, by the first terminal device, third configuration information sent by the network device, wherein the third configuration information is used for indicating the number of the first terminal device. 
     In a second aspect, a discontinuous reception method is provided. The method includes: determining, by a network device, at least one piece of discontinuous reception (DRX) information of at least one terminal device, wherein DRX information of each terminal device of the at least one terminal device is used for indicating that the each terminal device wakes up or sleeps during an on-duration of a DRX cycle after the DRX information of the each terminal device; and sending, by the network device, a downlink control channel to a first terminal device, wherein the downlink control channel carries the at least one piece of DRX information, so that the first terminal device determines DRX information of the first terminal device from the at least one piece of DRX information, and wakes up or sleeps during the on-duration according to the DRX information of the first terminal device. 
     Therefore, a network device realizes indication of DRX information at the device level by simultaneously indicating multiple pieces of DRX information of multiple terminal devices to the multiple terminal devices, so that the multiple terminal devices can wake up or sleep during an on-duration in a subsequent DRX cycle according to the respective DRX information after determining the respective DRX information from the multiple pieces of DRX information. Thus a terminal device that is not scheduled in the subsequent DRX cycle can sleep during the on-duration in the DRX cycle, further reducing power consumption. 
     In one possible implementation, the downlink control channel carries at least one bit value, the at least one bit value corresponds to the at least one piece of DRX information one by one, and each bit value in the at least one bit value is used for representing DRX information corresponding to the each bit value. 
     In one possible implementation, before the network device sends the downlink control channel to the first terminal device, the method further includes: sending, by the network device, a mapping relationship between multiple control channel groups and multiple radio network temporary identities (RNTIs) to the first terminal device, wherein a target RNTI used by the first terminal device for detecting the downlink control channel is an RNTI corresponding to a control channel group to which the downlink control channel belongs. 
     In one possible implementation, before the network device sends the downlink control channel to the first terminal device, the method further includes: sending, by the network device, first configuration information to the first terminal device, wherein the first configuration information indicates a target RNTI used for detecting the downlink control channel. 
     In one possible implementation, before the network device sends the downlink control channel to the first terminal device, the method further includes: sending, by the network device, second configuration information to the first terminal device, wherein the second configuration information is used for indicating a channel format of the downlink control channel. 
     In one possible implementation, sending, by the network device, the downlink control channel to a first terminal device includes: sending, by the network device, the downlink control channel to the first terminal device before the DRX cycle; or sending, by the network device, the downlink control channel to the first terminal device in a first subframe or a first slot during the on-duration of the DRX cycle; or sending, by the network device, the downlink control channel to the first terminal device in a common search space of a control channel. 
     In one possible implementation, before the network device sends the downlink control channel to the first terminal device, the method further includes: sending, by the network device, third configuration information to the first terminal device, wherein the third configuration information indicates a number of the first terminal device, and the DRX information of the first terminal device is DRX information corresponding to the number in the at least one piece of DRX information. 
     In a third aspect, a terminal device is provided. The terminal device may perform operations of the terminal device in the first aspect or any optional implementation of the first aspect. Specifically, the terminal device may include modules configured to perform operations of the terminal device in the first aspect or any possible implementation of the first aspect. 
     In a fourth aspect, a network device is provided. The network device may perform operations of the network device in the second aspect or any optional implementation of the second aspect. Specifically, the network device may include modules configured to perform operations of the network device in the second aspect or any possible implementation of the second aspect. 
     In a fifth aspect, a terminal device is provided. The terminal device includes: a processor, a transceiver, and a memory. The processor, the transceiver, and the memory communicate with each other through an internal connection path. The memory is configured to store instructions, and the processor is configured to execute the instructions stored in the memory. When the processor executes the instructions stored in the memory, the execution causes the terminal device to execute the method in the first aspect or any possible implementation of the first aspect, or the execution causes the terminal device to implement the terminal device provided in the third aspect. 
     In a sixth aspect, a network device is provided. The network device includes: a processor, a transceiver, and a memory. The processor, the transceiver, and the memory communicate with each other through an internal connection path. The memory is configured to store instructions, and the processor is configured to execute the instructions stored in the memory. When the processor executes the instructions stored in the memory, the execution causes the network device to execute the method in the second aspect or any possible implementation of the second aspect, or the execution causes the network device to implement the network device provided in the fourth aspect. 
     In a seventh aspect, a computer-readable storage medium is provided. The computer-readable storage medium stores a program that causes a terminal device to execute any discontinuous reception method in the first aspect and various implementations thereof. 
     In an eighth aspect, a computer-readable storage medium is provided. The computer-readable storage medium stores a program that causes a network device to execute any discontinuous reception method in the second aspect and various implementations thereof. 
     In a ninth aspect, a system chip is provided. The system chip includes an input interface, an output interface, a processor, and a memory, wherein the processor is configured to execute instructions stored in the memory, and when the instructions are executed, the processor may implement the method in the above first aspect or in any possible implementation of the first aspect. 
     In a tenth aspect, a system chip is provided. The system chip includes an input interface, an output interface, a processor, and a memory, wherein the processor is configured to execute instructions stored in the memory, and when the instructions are executed, the processor may implement the method in the above second aspect or in any possible implementation of the second aspect. 
     In an eleventh aspect, a computer program product containing instructions is provided, when the computer program product is run on a computer, the computer is caused to execute the method in the above first aspect or in any possible implementation of the first aspect. 
     In a twelfth aspect, a computer program product containing instructions is provided, when the computer program product is run on a computer, the computer is caused to execute the method in the above second aspect or in any possible implementation of the second aspect. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic diagram of architecture of an application scenario according to an implementation of the present application. 
         FIG. 2  is a schematic diagram of a DRX cycle. 
         FIG. 3  is a schematic flowchart of a discontinuous reception method according to an implementation of the present application. 
         FIG. 4  is a schematic flowchart of a discontinuous reception method according to an implementation of the present application. 
         FIG. 5  is a schematic block diagram of a terminal device according to an implementation of the present application. 
         FIG. 6  is a schematic block diagram of a network device according to an implementation of the present application. 
         FIG. 7  is a schematic structural diagram of a terminal device according to an implementation of the present application. 
         FIG. 8  is a schematic structural diagram of a network device according to an implementation of the present application. 
         FIG. 9  is a schematic structural diagram of a system chip according to an implementation of the present application. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, technical solutions in the implementations of the present application will be described with reference to the accompanying drawings. 
     It should be understood that the technical solutions of the implementations of the present application may be applied to various communication systems, such as a Global System of Mobile Communication (GSM) system, a Code Division Multiple Access (CDMA) system, a Wideband Code Division Multiple Access (WCDMA) system, a Long Term Evolution (LTE) system, a LTE Frequency Division Duplex (FDD) system, a LTE Time Division Duplex (TDD) system, a Universal Mobile Telecommunication System (UMTS), and a future 5G communication system. 
     Various implementations are described herein in connection with terminal devices in the present application. The terminal device may refer to a User Equipment (UE), an access terminal, a subscriber unit, a subscriber station, a mobile station, a mobile platform, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communication device, a user agent, or a user apparatus. The access terminal may be a cellular phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), a handheld device with a wireless communication function, a computing device or another processing device connected to a wireless modem, an on-board device, a wearable device, a terminal device in a future 5G network, or a terminal device in a future evolving Public Land Mobile Network (PLMN), etc. 
     Various implementations are described herein in connection with a network device in the present application. The network device may be a device for communicating with a terminal device, such as a Base Transceiver Station (BTS) in a GSM system or a CDMA system, a NodeB (NB) in a WCDMA system, or an Evolutional Node B (eNB or eNodeB) in an LTE system, or the network device may be a relay station, an access point, a vehicle-mounted device, a wearable device, a network side device in a future 5G network, or a network side device in a future evolved PLMN network, etc. 
       FIG. 1  is a schematic diagram of an application scenario of an implementation of the present application. The communication system in  FIG. 1  may include a network device  10  and a terminal device  20 . The network device  10  is configured to provide communication services for the terminal device  20  and is connected to a core network. The terminal device  20  may access the network by searching for a synchronization signal, or a broadcast signal or other signals, transmitted by the network device  10 , to communicate with the network. Arrows shown in  FIG. 1  may represent uplink/downlink transmission through cellular links between the terminal device  20  and the network device  10 . 
     The network in the implementation of the present application may refer to a Public Land Mobile Network (PLMN) or a device-to-device (D2D) network or a machine-to-machine/man (M2M) network or other networks.  FIG. 1  is a simplified schematic diagram of an example, and other terminal devices may be included in the network and are not shown in FIG. 
     The DRX cycle of the terminal device includes an on-duration and an Opportunity for DRX. As shown in  FIG. 2 , the terminal device can detect (or monitor) a Physical Downlink Control Channel (PDCCH) during the on-duration, while during the Opportunity for DRX, the terminal device can reduce power consumption by stopping receiving the PDCCH (in this case, the terminal device stops the blind detection of the PDCCH), thus prolonging battery life. In other words, during the on-duration period, the terminal device is in a wake-up state so as to detect the PDCCH, and during the Opportunity for DRX, the terminal device enters a sleep state so as not to detect a channel or signal. 
     Although the network configures the terminal device with the DRX cycle so that the terminal device periodically detects the PDCCH during the on-duration, the terminal device is scheduled only by chance during the on-duration. Even when the service load is very low, the terminal device will be scheduled only in a few DRX cycles. For a paging message using the DRX mechanism, the terminal has less chance of receiving the paging message. Therefore, after being configured with the DRX mechanism, the terminal device may detect no control channel during on-durations of most DRX cycles, but it will still be woken up during the on-duration of these DRX cycles, which increases unnecessary power consumption of the terminal device. Therefore, different terminal devices need to know whether they are actually scheduled during the on-duration in the DRX cycle, so as to remain asleep when not scheduled to further reduce power consumption. 
       FIG. 3  is a schematic flowchart of a discontinuous reception method according to an implementation of the present application. The method shown in  FIG. 3  may be performed by a terminal device. The terminal device is a first terminal device. The first terminal device may be, for example, a terminal device  20  shown in  FIG. 1 . As shown in  FIG. 3 , the discontinuous reception method includes acts  310 - 330 . 
     In act  310 , a first terminal device detects a downlink control channel sent by a network device, wherein the downlink control channel carries at least one piece of DRX information of at least one terminal device. 
     DRX information of each terminal device of the at least one terminal device is used for indicating that the each terminal device wakes up or sleeps during an on-duration of a DRX cycle after the DRX information of the each terminal device is detected. 
     In other words, DRX information of each terminal device of the at least one terminal device is used for indicating that the each terminal device wakes up or sleeps during an on-duration after the moment when the DRX information of the each terminal device is detected. The on-duration after this moment may include an on-duration in a DRX cycle where the DRX information is received, or an on-duration in a DRX cycle next to a DRX cycle where the DRX information is received. 
     Specifically, the network device sends the downlink control channel to the at least one terminal device to simultaneously indicate the respective DRX information to the at least one terminal device. DRX information of each terminal device is used for indicating that the each terminal device wakes up or sleeps during an on-duration of a DRX cycle after the moment when the DRX information of the each terminal device is detected. In other words, DRX information of each terminal device represents whether or not the each terminal device is scheduled during an on-duration of a DRX cycle after the moment when the DRX information of the each terminal device is detected. If a terminal device is scheduled, the terminal device needs to wake up. If the terminal device is not scheduled, the terminal device sleeps to reduce power consumption. For example, if the first terminal device detects the downlink control channel in the ith DRX cycle and acquires its own DRX information, then the DRX information may indicate the first terminal device to wake up or sleep during an on-duration of the (i+1)th DRX cycle. 
     Optionally, the downlink control channel carries at least one bit value, the at least one bit value corresponds to the at least one piece of DRX information one by one, and each bit value in the at least one bit value is used for representing DRX information corresponding to the each bit value. 
     For example, as shown in Table One, it is assumed that the downlink control channel includes N bit values, which are respectively used for representing DRX information of N terminal devices. The N bit values correspond to N pieces of DRX information of the N terminal devices one by one. If a bit value of the N bit values is 0, it indicates that DRX information corresponding to the bit value is used for indicating the terminal device to sleep during the on-duration of the subsequent DRX cycle without detecting a PDCCH, etc. If a bit value of the N bit values is 1, it indicates that DRX information corresponding to the bit value is used for indicating the terminal device to wake up during the on-duration of the subsequent DRX cycle to detect information such as a PDCCH or a paging message. 
     
       
         
           
               
               
             
               
                   
                 TABLE ONE 
               
             
            
               
                   
                   
               
               
                   
                 N Bit Values 
               
            
           
           
               
               
               
               
               
               
            
               
                 Bit Value 
                 1 
                 0 
                 1 
                 . . . 
                 1 
               
               
                   
               
               
                 DRX Information 
                 Wake Up 
                 Sleep 
                 Wake Up 
                 . . . 
                 Wake Up 
               
               
                   
               
            
           
         
       
     
     Of course, it is also possible to use a bit value of 0 to indicate a terminal device to wake up and use a bit value of 1 to indicate a terminal device to sleep. In other words, if a bit value of the N bit values is 1, it indicates that DRX information corresponding to the bit value is used for indicating the terminal device to sleep during the on-duration of the subsequent DRX cycle without detecting a PDCCH, etc. If a bit value of the N bit values is 0, it indicates that DRX information corresponding to the bit value is used for indicating the terminal device to wake up during the on-duration of the subsequent DRX cycle to detect information such as a PDCCH or a paging message. Table 1 just illustrates an example. 
     Optionally, before act  310 , that is, before the first terminal device detects the downlink control channel sent by the network device, the method further includes: determining, by the first terminal device, a control channel group to which the downlink control channel belongs according to a device identity of the first terminal device; and determining, by the first terminal device, a target radio network temporary identity (RNTI) corresponding to the control channel group according to a mapping relationship between multiple control channel groups and multiple RNTIs. 
     In this case, in act  310 , detecting, by the first terminal device, the downlink control channel sent by the network device includes: detecting, by the first terminal device, the downlink control channel according to the target RNTI. 
     For example, the first terminal device calculates a number of the control channel group that the downlink control channel is in according to the device identity (ID) of the first terminal device, such as UE-ID, and based on UE-ID mod M. M is a positive integer and M is the total quantity of control channel groups. The first terminal device determines an RNTI used for detecting the downlink control channel according to the calculated number of the control channel group and the mapping relationship between M control channel groups and M RNTIs, and detects the downlink control channel according to the target RNTI. 
     Optionally, the mapping relationship between multiple control channel groups and multiple RNTIs may be notified by the network device through a radio resource control (RRC) signaling to the terminal device, or the mapping relationship may be pre-agreed between the terminal device and the network device and pre-stored in the terminal device. In addition, the mapping relationship between multiple control channel groups and multiple RNTIs may be presented by any means such as a chart, table, formula, etc. 
     Optionally, before act  310 , that is, before the first terminal device detects the downlink control channel sent by the network device, the method further includes: receiving, by the first terminal device, first configuration information sent by the network device, wherein the first configuration information indicates a target RNTI used for detecting the downlink control channel; 
     In this case, in act  310 , detecting, by the first terminal device, the downlink control channel sent by the network device includes: detecting, by the first terminal device, the downlink control channel according to the target RNTI. 
     The first configuration information may be, for example, sent by the network device to the first terminal device through an RRC signaling or a Medium Access Control (MAC) Control Element (CE), and the first terminal device may directly obtain the target RNTI through the received RRC signaling or MAC CE. 
     Optionally, before act  310 , that is, before the first terminal device detects the downlink control channel sent by the network device, the method further includes: receiving, by the first terminal device, second configuration information sent by the network device, wherein the second configuration information is used for indicating a channel format of the downlink control channel. 
     In this case, in act  310 , detecting, by the first terminal device, the downlink control channel sent by the network device includes: detecting, by the first terminal device, the downlink control channel according to the channel format of the downlink control channel. 
     The second configuration information may be, for example, sent by the network device to the first terminal device through an RRC signaling or an MAC CE, and the first terminal device may acquire a channel format used for detecting the downlink control channel through the received RRC signaling or MAC CE. 
     For example, it is assumed that the downlink control channel carries Download Control Information (DCI), and the DCI carries N pieces of DRX information of N terminal devices. If N is large, that is, the network device needs to send the downlink control channel to a large number of terminal devices at the same time, then the network device may use the first DCI format to send the downlink control channel carrying the DCI; If N is small, that is, the network device needs to send the downlink control channel to a small number of terminal devices at the same time, then the terminal device may use the second DCI format to send the downlink control channel carrying the DCI. The quantity of bits used for representing multiple pieces of DRX information in the DCI of the first DCI format is greater than the quantity of bits used for representing multiple pieces of DRX information in the DCI of the second DCI format. The network device indicates the used channel format (e.g., the first DCI format or the second DCI format) to the first terminal device, so that the first terminal device may detect the DCI including its own DRX information carried on the downlink control channel based on the corresponding DCI format. 
     Optionally, in act  310 , detecting, by the first terminal device, the downlink control channel sent by the network device includes: detecting, by the first terminal device, the downlink control channel sent by the network device before the DRX cycle; or detecting, by the first terminal device, the downlink control channel sent by the network device in a first subframe or a first slot during the on-duration of the DRX cycle; or detecting, by the first terminal device, the downlink control channel sent by the network device in a common search space of a control channel. 
     For example, if the first terminal device detects the downlink control channel in the ith DRX cycle and determines its own DRX information according to the downlink control channel, then the DRX information may indicate the first terminal device to wake up or sleep during an on-duration of the (i+1)th DRX cycle, or indicate the first terminal device to wake up or sleep during on-durations of the (i+1)th DRX cycle and several DRX cycles after the (i+1)th DRX cycle. 
     For another example, if the first terminal device may detect the downlink control channel in the first subframe or the first slot in the on-duration of the ith DRX cycle and determine its own DRX information according to the downlink control channel, then the DRX information may indicate the first terminal device to wake up or sleep during the on-duration in the ith DRX cycle. For instance, the first terminal device detects the downlink control channel in the first subframe in the on-duration of a certain DRX cycle and knows that sleep is to be performed during the on-duration of the DRX cycle, the first terminal device may go to sleep from the second subframe in the on-duration of the DRX cycle till the end of the DRX cycle to reduce power consumption. 
     For another example, if the first terminal device detects the downlink control channel in the common search space of a control channel and determines its own DRX information according to the downlink control channel, then the DRX information indicates the first terminal device to wake up or sleep during an on-duration in one or more DRX cycles after the moment when the DRX information is detected. 
     In act  320 , the first terminal device determines DRX information of the first terminal device from the at least one piece of DRX information. 
     Optionally, determining, by the first terminal device, the DRX information of the first terminal device from the at least one piece of DRX information according to the downlink control channel includes: determining, by the first terminal device, the DRX information of the first terminal device according to a number of the first terminal device, wherein the DRX information of the first terminal device is DRX information corresponding to the number in the at least one piece of DRX information. 
     Optionally, before the first terminal device determines the DRX information of the first terminal device according to the number of the first terminal device, the method further includes: receiving, by the first terminal device, third configuration information sent by the network device, wherein the third configuration information is used for indicating the number of the first terminal device. 
     The third configuration information may be, for example, sent by the network device to the first terminal device through an RRC signaling or an MAC CE, and the first terminal device may acquire the number of the first terminal device through the received RRC signaling or MAC CE. 
     For example, as shown in Table Two, it is assumed that the downlink control channel includes N bit values, which are respectively used for representing DRX information of N terminal devices. The N bit values correspond to N pieces of DRX information of N terminal devices one by one. When numbers of terminal devices are different, the corresponding pieces of DRX information are different, which indicates that the bit values of the DRX information are also different. If the network device informs that the number of the first terminal device is 1, the first terminal device wakes up during the on-duration of a next DRX cycle according to the corresponding bit value of 1. If the network device informs that the number of the first terminal device is 2, the first terminal device sleeps during the on-duration of a next DRX cycle according to the corresponding bit value of 0. If the network device informs that the number of the first terminal device is N, the first terminal device wakes up during the on-duration of a next DRX cycle according to the corresponding bit value of 1. 
     
       
         
           
               
               
             
               
                   
                 TABLE TWO 
               
             
            
               
                   
                   
               
               
                   
                 Terminal Device Number 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 1 
                 2 
                 3 
                 . . . 
                 N 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 Bit Value 
                 1 
                 0 
                 1 
                 . . . 
                 1 
               
               
                 DRX Information 
                 Wake Up 
                 Sleep 
                 Wake Up 
                 . . . 
                 Wake Up 
               
               
                   
               
            
           
         
       
     
     In act  330 , the first terminal device wakes up or sleeps during the on-duration of the DRX cycle according to the DRX information of the first terminal device. 
     Therefore, a network device simultaneously indicates multiple pieces of DRX information of multiple terminal devices to the multiple terminal devices, and a first terminal device of the multiple terminal devices determines its own DRX information among the multiple pieces of DRX information and wakes up or sleeps during an on-duration of a subsequent DRX cycle according to its own DRX information. Since the first terminal device can sleep during the on-duration of the DRX cycle when it is not scheduled in the subsequent DRX cycle, the power consumption of the first terminal device is further reduced. 
       FIG. 4  is a schematic flowchart of a discontinuous reception method according to an implementation of the present application. The method shown in  FIG. 4  may be performed by a network device. The network device may be, for example, a network device  10  shown in  FIG. 1 . As shown in  FIG. 4 , the discontinuous reception method includes: acts  410 - 420 . 
     In act  410 , a network device determines at least one piece of discontinuous reception (DRX) information of at least one terminal device, wherein DRX information of each terminal device of the at least one terminal device is used for indicating that the each terminal device wakes up or sleeps during an on-duration of a DRX cycle after the DRX information of the each terminal device. 
     In act  420 , the network device sends a downlink control channel to a first terminal device, wherein the downlink control channel carries the at least one piece of DRX information, so that the first terminal device determines DRX information of the first terminal device from the at least one piece of DRX information, and wakes up or sleeps during the on-duration according to the DRX information of the first terminal device. 
     Therefore, a network device realizes indication of DRX information at the device level by simultaneously indicating multiple pieces of DRX information of multiple terminal devices to the multiple terminal devices, so that the multiple terminal devices can wake up or sleep during an on-duration in a subsequent DRX cycle according to the respective DRX information after determining the respective DRX information from the multiple pieces of DRX information. Thus a terminal device that is not scheduled in the subsequent DRX cycle can sleep during the on-duration of the DRX cycle, further reducing power consumption. 
     Optionally, the downlink control channel carries at least one bit value, the at least one bit value corresponds to the at least one piece of DRX information one by one, and each bit value in the at least one bit value is used for representing DRX information corresponding to the each bit value. 
     Optionally, before the network device sends the downlink control channel to the first terminal device, the method further includes: sending, by the network device, a mapping relationship between multiple control channel groups and multiple radio network temporary identities (RNTIs) to the first terminal device, wherein a target RNTI used by the first terminal device for detecting the downlink control channel is an RNTI corresponding to a control channel group to which the downlink control channel belongs. 
     Optionally, before the network device sends the downlink control channel to the first terminal device, the method further includes: sending, by the network device, first configuration information to the first terminal device, wherein the first configuration information indicates a target RNTI used for detecting the downlink control channel. 
     Optionally, before the network device sends the downlink control channel to the first terminal device, the method further includes: sending, by the network device, second configuration information to the first terminal device, wherein the second configuration information is used for indicating a channel format of the downlink control channel. 
     The second configuration information may be, for example, sent by the network device to the first terminal device through an RRC signaling or an MAC CE, and the first terminal device may acquire a channel format used for detecting the downlink control channel through the received RRC signaling or MAC CE. 
     Optionally, sending, by the network device, the downlink control channel to a first terminal device includes: sending, by the network device, the downlink control channel to the first terminal device before the DRX cycle; or sending, by the network device, the downlink control channel to the first terminal device in a first subframe or a first slot during the on-duration of the DRX cycle; or sending, by the network device, the downlink control channel to the first terminal device in a common search space of a control channel. 
     For example, the network device may send the downlink control channel to the at least one terminal device. If the first terminal device in the at least one terminal device detects the downlink control channel in the ith DRX cycle of the first terminal device, DRX information of the first terminal device carried in the downlink control channel may indicate that the first terminal device wakes up or sleeps during the on-duration of the (i+1)th DRX cycle of the first terminal device, or indicate the first terminal device to wake up or sleep during on-durations of the (i+1)th DRX cycle and several DRX cycles after the (i+1)th DRX cycle of the first terminal device. 
     For another example, the network device may send the downlink control channel to the at least one terminal device. If the first terminal device in the at least one terminal device detects the downlink control channel in the first subframe or the first slot during the on-duration in the ith DRX cycle of the first terminal device, DRX information of the first terminal device carried in the downlink control channel may indicate the first terminal device to wakes up or sleep during the on-duration of the ith DRX cycle of the first terminal device. For instance, the network device sends the downlink control channel in the first subframe in the on-duration of a certain DRX cycle of the first terminal device, the first terminal device detects the downlink control channel and knows that sleep is to be performed during the on-duration of the DRX cycle, and the first terminal device may go to sleep from the second subframe in the on-duration of the DRX cycle till the end of the DRX cycle to reduce power consumption. 
     For another example, the network device may send the downlink control channel to the at least one terminal device in the common search space of the control channel, so as to indicate each terminal device to wake up or sleep during an on-duration in one or more DRX cycles after the moment when its own DRX information is detected. 
     Optionally, before the network device sends the downlink control channel to the first terminal device, the method further includes: sending, by the network device, third configuration information to the first terminal device, wherein the third configuration information indicates a number of the first terminal device, and the DRX information of the first terminal device is DRX information corresponding to the number in the at least one piece of DRX information. 
     It should be understood that the specific details of the network device in the process of indicating DRX information may refer to the above description of the terminal device in  FIG. 3 , which is not repeated here for the sake of brevity. 
     It should be understood that in various implementations of the present disclosure, values of sequence numbers in the aforementioned processes do not indicate an order of execution, and the order of execution of various processes should be determined by their functions and internal logics, and should not constitute any limitation on implementation processes of implementations of the present application. 
       FIG. 5  is a schematic block diagram of a terminal device  500  according to an implementation of the present application. The terminal device is a first terminal device. As shown in  FIG. 5 , the first terminal device  500  includes a transceiving unit  510 , a determination unit  520 , and a processing unit  530 . 
     The transceiving unit  510  is configured to detect a downlink control channel sent by a network device, wherein the downlink control channel carries at least one piece of discontinuous reception (DRX) information of at least one terminal device, and DRX information of each terminal device of the at least one terminal device is used for indicating that the each terminal device wakes up or sleeps during an on-duration of a DRX cycle after the DRX information of the each terminal device. 
     The determination unit  520  is configured to determine DRX information of the first terminal device from the at least one piece of DRX information detected by the transceiving unit  510 . 
     The processing unit  530  is configured to wake up or sleep during the on-duration according to the DRX information of the first terminal device determined by the determination unit  520 . 
     Therefore, a network device simultaneously indicates multiple pieces of DRX information of multiple terminal devices to the multiple terminal devices, and a first terminal device of the multiple terminal devices determines its own DRX information among the multiple pieces of DRX information and wakes up or sleeps during an on-duration of a subsequent DRX cycle according to its own DRX information. Since the first terminal device can sleep during the on-duration of the DRX cycle when it is not scheduled in the subsequent DRX cycle, the power consumption of the first terminal device is further reduced. 
     Optionally, the downlink control channel carries at least one bit value, the at least one bit value corresponds to the at least one piece of DRX information one by one, and each bit value in the at least one bit value is used for representing DRX information corresponding to the each bit value. 
     Optionally, the determination unit  520  is further configured to: determine a control channel group to which the downlink control channel belongs according to a device identity of the first terminal device; and determine a target radio network temporary identity (RNTI) corresponding to the control channel group according to a mapping relationship between multiple control channel groups and multiple RNTIs. 
     The transceiving unit  510  is specifically configured to: detect the downlink control channel according to the target RNTI. 
     Optionally, the transceiving unit  510  is further configured to: receive first configuration information sent by the network device, wherein the first configuration information indicates a target RNTI used for detecting the downlink control channel; and detect the downlink control channel according to the target RNTI. 
     Optionally, the transceiving unit  510  is further configured to: receive second configuration information sent by the network device, wherein the second configuration information is used for indicating a channel format of the downlink control channel; and detect the downlink control channel according to the channel format of the downlink control channel. 
     Optionally, the transceiving unit  510  is specifically configured to: detect the downlink control channel sent by the network device before the DRX cycle; or detect the downlink control channel sent by the network device in a first subframe or a first slot during the on-duration of the DRX cycle; or detect the downlink control channel sent by the network device in a common search space of a control channel. 
     Optionally, the determination unit  520  is specifically configured to: determine the DRX information of the first terminal device according to a number of the first terminal device, wherein the DRX information of the first terminal device is DRX information corresponding to the number in the at least one piece of DRX information. 
     Optionally, the transceiving unit  510  is further configured to: receive third configuration information sent by the network device, wherein the third configuration information is used for indicating the number of the first terminal device. 
       FIG. 6  is a schematic block diagram of a network device  600  according to an implementation of the present application. As shown in  FIG. 6 , the network device  600  includes a determination unit  610  and a transceiving unit  620 . 
     The determination unit  610  is configured to determine at least one piece of discontinuous reception (DRX) information of at least one terminal device, wherein DRX information of each terminal device of the at least one terminal device is used for indicating that the each terminal device wakes up or sleeps during an on-duration of a DRX cycle after the DRX information of the each terminal device. 
     The transceiving unit  620  is configured to send a downlink control channel to a first terminal device, wherein the downlink control channel carries the at least one piece of DRX information determined by the determination unit  610 , so that the first terminal device determines DRX information of the first terminal device from the at least one piece of DRX information, and wakes up or sleeps during the on-duration according to the DRX information of the first terminal device. 
     Therefore, a network device realizes indication of DRX information at the device level by simultaneously indicating multiple pieces of DRX information of multiple terminal devices to the multiple terminal devices, so that the multiple terminal devices can wake up or sleep during an on-duration of a subsequent DRX cycle according to the respective DRX information after determining the respective DRX information from the multiple pieces of DRX information. Thus a terminal device that is not scheduled in the subsequent DRX cycle can sleep during the on-duration of the DRX cycle, further reducing power consumption. 
     Optionally, the downlink control channel carries at least one bit value, the at least one bit value corresponds to the at least one piece of DRX information one by one, and each bit value in the at least one bit value is used for representing DRX information corresponding to the each bit value. 
     Optionally, the transceiving unit  620  is further configured to: send a mapping relationship between multiple control channel groups and multiple radio network temporary identities (RNTIs) to the first terminal device, wherein a target RNTI used by the first terminal device for detecting the downlink control channel is an RNTI corresponding to a control channel group to which the downlink control channel belongs. 
     Optionally, the transceiving unit  620  is further configured to: send first configuration information to the first terminal device, wherein the first configuration information indicates a target RNTI used for detecting the downlink control channel. 
     Optionally, the transceiving unit  620  is further configured to: send second configuration information to the first terminal device, wherein the second configuration information is used for indicating a channel format of the downlink control channel. 
     Optionally, the transceiving unit  620  is specifically configured to: send the downlink control channel to the first terminal device before the DRX cycle; or send the downlink control channel to the first terminal device in a first subframe or a first slot during the on-duration of the DRX cycle; or send the downlink control channel to the first terminal device in a common search space of a control channel. 
     Optionally, the transceiving unit  620  is further configured to: send third configuration information to the first terminal device, wherein the third configuration information indicates a number of the first terminal device, and the DRX information of the first terminal device is DRX information corresponding to the number in the at least one piece of DRX information. 
       FIG. 7  is a schematic structural diagram of a terminal device  700  according to an implementation of the present application. As shown in  FIG. 7 , the terminal device includes a processor  710 , a transceiver  720 , and a memory  730 , wherein the processor  710 , the transceiver  720 , and the memory  730  communicate with each other through an internal connection path. The memory  730  is configured to store instructions, and the processor  710  is configured to execute instructions stored in the memory  730  to control the transceiver  720  to send or receive signals. The transceiver  720  is configured to: detect a downlink control channel sent by a network device, wherein the downlink control channel carries at least one piece of discontinuous reception (DRX) information of at least one terminal device, and DRX information of each terminal device of the at least one terminal device is used for indicating that the each terminal device wakes up or sleeps during an on-duration of a DRX cycle after the DRX information of the each terminal device. 
     The processor  710  is configured to: determine DRX information of the first terminal device from the at least one piece of DRX information detected by the transceiver  720 ; and wake up or sleep during the on-duration according to the DRX information of the first terminal device. 
     Therefore, a network device simultaneously indicates multiple pieces of DRX information of multiple terminal devices to the multiple terminal devices, and a first terminal device of the multiple terminal devices determines its own DRX information among the multiple pieces of DRX information and wakes up or sleeps during an on-duration of a subsequent DRX cycle according to its own DRX information. Since the first terminal device can sleep during the on-duration of the DRX cycle when it is not scheduled in the subsequent DRX cycle, the power consumption of the first terminal device is further reduced. 
     Optionally, the downlink control channel carries at least one bit value, the at least one bit value corresponds to the at least one piece of DRX information one by one, and each bit value in the at least one bit value is used for representing DRX information corresponding to the each bit value. 
     Optionally, the processor  710  is further configured to: determine a control channel group to which the downlink control channel belongs according to a device identity of the first terminal device; and determine a target radio network temporary identity (RNTI) corresponding to the control channel group according to a mapping relationship between multiple control channel groups and multiple RNTIs. 
     The transceiver  720  is specifically configured to: detect the downlink control channel according to the target RNTI. 
     Optionally, the transceiver  720  is further configured to: receive first configuration information sent by the network device, wherein the first configuration information indicates a target RNTI used for detecting the downlink control channel; and detect the downlink control channel according to the target RNTI. 
     Optionally, the transceiver  720  is further configured to: receive second configuration information sent by the network device, wherein the second configuration information is used for indicating a channel format of the downlink control channel; and detect the downlink control channel according to the channel format of the downlink control channel. 
     Optionally, the transceiver  720  is specifically configured to: detect the downlink control channel sent by the network device before the DRX cycle; or detect the downlink control channel sent by the network device in a first subframe or a first slot during the on-duration of the DRX cycle; or detect the downlink control channel sent by the network device in a common search space of a control channel. 
     Optionally, the processor  710  is specifically configured to: determine the DRX information of the first terminal device according to a number of the first terminal device, wherein the DRX information of the first terminal device is DRX information corresponding to the number in the at least one piece of DRX information. 
     Optionally, the transceiver  720  is further configured to: receive third configuration information sent by the network device, wherein the third configuration information is used for indicating the number of the first terminal device. 
     It should be understood that, in an implementation of the present application, the processor  710  may be a central processing unit (CPU), or the processor  710  may be another general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or another programmable logic device, a discrete gate or a transistor logic device, or 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. 
     The memory  730  may include a read only memory and a random access memory, and provide instructions and data to the processor  710 . A portion of memory  730  may include non-transitory random access memory. 
     In an implementation process, the acts of the methods described above may be accomplished by integrated logic circuits of hardware in the processor  710  or instructions in a form of software. The acts of the positioning method disclosed in the implementation of the present application may be directly accomplished by an execution of a hardware processor or accomplished by a combination of hardware and software modules in the processor  710 . The software modules may be located in a storage medium commonly used in the art, such as a random access memory, flash memory, read-only memory, programmable read-only memory or electrically erasable programmable memory, or register. The storage medium is located in the memory  730 , and the processor  710  reads the information in the memory  730  and accomplishes the acts of the above method in combination with its hardware. In order to avoid repetition, it will not be described in detail here. 
     The terminal device  700  according to the implementation of the present application may correspond to the terminal device for executing the method  300  in the method  300  and the terminal device  500  according to the implementation of the present application, and various units or modules in the terminal device  700  are respectively used for executing various acts or processing processes executed by the terminal device in the method  300 . Here, in order to avoid redundancy, detailed description thereof is omitted. 
       FIG. 8  is a schematic structural diagram of a network device  800  according to an implementation of the present application. As shown in  FIG. 8 , the network device includes a processor  810 , a transceiver  820 , and a memory  830 , wherein the processor  810 , the transceiver  820 , and the memory  830  communicate with each other through an internal connection path. The memory  830  is configured to store instructions, and the processor  810  is configured to execute instructions stored in the memory  830  to control the transceiver  820  to send or receive signals. The processor  810  is configured to: determine at least one discontinuous reception (DRX) information of at least one terminal device, wherein DRX information of each terminal device of the at least one terminal device is used for indicating that the each terminal device wakes up or sleeps during an on-duration of a DRX cycle after the DRX information of the each terminal device. 
     The transceiver  820  is configured to: send a downlink control channel to a first terminal device, wherein the downlink control channel carries the at least one piece of DRX information determined by the processor  810 , so that the first terminal device determines DRX information of the first terminal device from the at least one piece of DRX information, and wakes up or sleeps during the on-duration according to the DRX information of the first terminal device. 
     Therefore, a network device realizes indication of DRX information at the device level by simultaneously indicating multiple pieces of DRX information of multiple terminal devices to the multiple terminal devices, so that the multiple terminal devices can wake up or sleep during an on-duration in a subsequent DRX cycle according to the respective DRX information after determining the respective DRX information from the multiple pieces of DRX information. Thus a terminal device that is not scheduled in the subsequent DRX cycle can sleep during the on-duration of the DRX cycle, further reducing power consumption. 
     Optionally, the downlink control channel carries at least one bit value, the at least one bit value corresponds to the at least one piece of DRX information one by one, and each bit value in the at least one bit value is used for representing DRX information corresponding to the each bit value. 
     Optionally, the transceiver  820  is further configured to: send a mapping relationship between multiple control channel groups and multiple radio network temporary identities (RNTIs) to the first terminal device, wherein a target RNTI used by the first terminal device for detecting the downlink control channel is an RNTI corresponding to a control channel group to which the downlink control channel belongs. 
     Optionally, the transceiver  820  is further configured to: send first configuration information to the first terminal device, wherein the first configuration information indicates a target RNTI used for detecting the downlink control channel. 
     Optionally, the transceiver  820  is further configured to: send second configuration information to the first terminal device, wherein the second configuration information is used for indicating a channel format of the downlink control channel. 
     Optionally, the transceiver  820  is specifically configured to: send the downlink control channel to the first terminal device before the DRX cycle; or send the downlink control channel to the first terminal device in a first subframe or a first slot during the on-duration of the DRX cycle; or send the downlink control channel to the first terminal device in a common search space of a control channel. 
     Optionally, the transceiver  820  is further configured to: send third configuration information to the first terminal device, wherein the third configuration information indicates a number of the first terminal device, and the DRX information of the first terminal device is DRX information corresponding to the number in the at least one piece of DRX information. 
     It should be understood that in the implementation of the present application, the processor  810  may be a Central Processing Unit (CPU), or the processor  810  may be another general purpose processor, a digital signal processors(DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or another programmable logic device, a discrete gate or transistor a logic device, or 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. 
     The memory  830  may include a read only memory and a random access memory, and provide instructions and data to the processor  810 . A portion of memory  830  may include non-transitory random access memory. In an implementation process, the acts of the methods described above may be accomplished by integrated logic circuits of hardware in the processor  810  or instructions in a form of software. The acts of the positioning method disclosed in the implementation of the present application may be directly accomplished by an execution of a hardware processor or accomplished by a combination of hardware and software modules in the processor  810 . The software modules may be located in a storage medium commonly used in the art, such as a random access memory, flash memory, read-only memory, programmable read-only memory or electrically erasable programmable memory, or register. The storage medium is located in the memory  830 , and the processor  810  reads the information in the memory  830  and accomplishes the acts of the above method in combination with its hardware. In order to avoid repetition, it will not be described in detail here. 
     The network device  800  according to the implementation of the present application may correspond to the network device for executing the method  400  in the method  400  and the network device  600  according to the implementation of the present application, and various units or modules in the network device  800  are respectively used for executing various acts or processing processes executed by the network device in the method  400 . Here, in order to avoid redundancy, detailed description thereof is omitted. 
       FIG. 9  is a schematic structural diagram of a system chip according to an implementation of the present application. The system chip  900  of  FIG. 9  includes an input interface  901 , an output interface  902 , at least one processor  903 , and a memory  904 . The input interface  901 , the output interface  902 , the processor  903 , and the memory  904  are connected to each other through an internal connection path. The processor  903  is configured to execute codes in the memory  904 . 
     Optionally, the processor  903  may implement the method  300  executed by the terminal device in the method implementation when the codes are executed. For the sake of brevity, it will not be repeated here. 
     Optionally, the processor  903  may implement the method  400  executed by the network device in the method implementation when the codes are executed. For the sake of brevity, it will not be repeated here. 
     Those of ordinary skill in the art will recognize that the example units and algorithm acts described in connection with the implementations disclosed herein may be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on a specific application and design constraint of the technical solution. Skilled in the art may use different methods to realize the described functions for each particular application, but such realization should not be considered to be beyond the scope of the present application. 
     Those skilled in the art may clearly understand that for convenience and conciseness of description, the specific working process of the system, apparatus and unit described above may refer to the corresponding process in the aforementioned implementations of methods, and details are not described herein again. 
     In several implementations provided by the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the apparatus implementation described above is only illustrative, for example, the division of the unit is only a logical function division, and there may be other ways of division in actual implementation, for example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. On the other hand, the mutual coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, apparatuses or units, and may be in electrical, mechanical or other forms. 
     The unit described as a separate component may or may not be physically separated, and the component shown as a unit may or may not be a physical unit, i.e., may be located in one place or may be distributed over multiple network units. Some or all of the units may be selected according to practical needs to achieve a purpose of the solution of the implementations. 
     In addition, various functional units in various implementations of the present application may be integrated in one detection unit, or various units may be physically present separately, or two or more units may be integrated in one unit. 
     The functions may be stored in a computer readable storage medium if implemented in a form of software functional units and sold or used as a separate product. Based on this understanding, the technical solution of the present application, in essence, or the part contributing to the existing art, or the part of the technical solution, may be embodied in the form of a software product stored in a storage medium, including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, or the like) to perform all or part of the acts of the methods described in various implementations of the present application. The aforementioned storage medium includes various media capable of storing program codes, such as a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk. 
     What are described above are merely example implementations of the present application, but the protection scope of the present application is not limited thereto. Any variation or substitution that may be easily conceived by any person skilled in the art within the technical scope disclosed by the present application shall be included within the protection scope of the present application. Therefore, the protection scope of the implementations of the present application should be subject to the protection scope of the claims.