Patent Publication Number: US-2021168857-A1

Title: Load control method and apparatus, network device, and terminal

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of the International application PCT/CN2018/106994, filed on Sep. 21, 2018, entitled “LOAD CONTROL METHOD AND APPARATUS, NETWORK DEVICE, AND TERMINAL”, the content of which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     Embodiments of the present application relate to the field of mobile communication technology and, in particular, relate to a load control method and apparatus, a network device and a terminal. 
     BACKGROUND 
     When a User Equipment (UE) accesses a network and obtains a Radio Resource Control (RRC) connection, a random access procedure is first required. A current random access procedure uses a four-step Random Access Procedure (4 step RACH). In order to shorten delay of the random access procedure and quickly enter the network to start a service, a two-step Random Access Procedure (2 step RACH) is proposed. In the 2 step RACH, resources for MSG3 are pre-configured. When many users use the 2 step RACH which leads to a relatively high load of 2 step RACH resources, collision probability will be increased, thereby further extending access delay. 
     SUMMARY 
     Embodiments of the present application provide a load control method and apparatus, a network device and a terminal. 
     A load control method provided by an embodiment of the present application includes: 
     sending, by a network device, a system broadcast message, where the system broadcast message includes a first configuration parameter, and the first configuration parameter is used to control whether a terminal performs a two-step random access procedure. 
     A load control method provided by an embodiment of the present application includes: 
     receiving, by a terminal, a system broadcast message sent by a network device, where the system broadcast message includes a first configuration parameter; 
     determining, by the terminal based on the first configuration parameter, whether to perform a two-step random access procedure. 
     A load control method provided by an embodiment of the present application includes: 
     detecting, by a network device, that a load of a Physical Random Access Channel (PRACH) used to perform a two-step random access procedure exceeds a first threshold, and sending, by the network device, first indication information to a terminal, where the first indication information instructs the terminal to perform a switching from the two-step random access procedure to a four-step random access procedure. 
     A load control method provided by an embodiment of the present application includes: 
     receiving, by a terminal, first indication information sent by a network device; 
     determining, by the terminal based on the first indication information, to perform a switching from a two-step random access procedure to a four-step random access procedure. 
     A load control apparatus provided by an embodiment of the present application includes: 
     a first sending unit, configured to send a system broadcast message, where the system broadcast message includes a first configuration parameter, and the first configuration parameter is used to control whether a terminal performs a two-step random access procedure. 
     A load control apparatus provided by an embodiment of the present application includes: 
     a first receiving unit, configured to receive a system broadcast message sent by a network device, where the system broadcast message includes a first configuration parameter; 
     a determining unit, configured to determine, based on the first configuration parameter, whether to perform a two-step random access procedure. 
     A load control apparatus provided by an embodiment of the present application includes: 
     a detecting unit, configured to detect that a load of a PRACH used to perform a two-step random access procedure exceeds a first threshold; 
     a sending unit, configured to send first indication information to a terminal, where the first indication information instructs the terminal to perform a switching from the two-step random access procedure to a four-step random access procedure. 
     A load control apparatus provided by an embodiment of the present application includes: 
     a receiving unit, configured to receive first indication information sent by a network device; 
     a determining unit, configured to determine, based on the first indication information, a switching from a two-step random access procedure to a four-step random access procedure. 
     A network device provided by an embodiment of the present application includes a processor and a memory. The memory is configured to store a computer program, and the processor is configured to call and run the computer program stored in the memory to execute the aforementioned load control method. 
     A terminal provided by an embodiment of the present application includes a processor and a memory. The memory is configured to store a computer program, and the processor is configured to call and run the computer program stored in the memory to execute the aforementioned load control method. 
     A chip provided by an embodiment of the present application is configured to implement the aforementioned load control method. 
     Specifically, the chip includes: a processor, configured to call and run a computer program from a memory, so that a device installed with the chip executes the above-mentioned load control method. 
     A computer-readable storage medium provided by an embodiment of the present application is configured to store a computer program, where the computer program causes a computer to execute the above-mentioned load control method. 
     A computer program product provided by an embodiment of the present application includes computer program instructions, where the computer program instructions cause a computer to execute the aforementioned load control method. 
     A computer program provided by an embodiment of the present application causes a computer to execute the above-mentioned load control method, when running on the computer. 
     Through the above technical solutions, a network side configures a load control parameter (i.e. the first configuration parameter) of the two-step random access procedure through system broadcast, and carries the first indication information to the terminal through a paging message or a random access response message, where the first indication information is used to instruct the terminal to determine whether to perform the switching from the two-step random access procedure to the four-step random access procedure. In this way, load control of 2 step RACH resources is realized and the load of 2 step RACH resources is prevented from being too high, thereby reducing conflict probability of user access. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The accompanying drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The exemplary embodiments of the present application and descriptions thereof are used to explain the present application, and do not constitute an improper limitation of the present application. In the accompanying drawings: 
         FIG. 1  is a schematic diagram of a communication system architecture provided by an embodiment of the present application; 
         FIG. 2  is a flowchart of a four-step random access procedure; 
         FIG. 3( a )  is a format of an E/T/R/R/BI MAC subheader; 
         FIG. 3( b )  is a format of an E/T/RAPID MAC subheader; 
         FIG. 3( c )  is a format of a MAC PDU (including MAC RARs); 
         FIG. 3( d )  is a schematic diagram of a MAC RAR; 
         FIG. 4  is a first schematic flowchart of a load control method provided by an embodiment of the present application; 
         FIG. 5  is a second schematic flowchart of a load control method provided by an embodiment of the present application; 
         FIG. 6  is a third schematic flowchart of a load control method provided by an embodiment of the present application; 
         FIG. 7  is a fourth schematic flowchart of a load control method provided by an embodiment of the present application; 
         FIG. 8  is a first schematic diagram of structural composition of a load control apparatus provided by an embodiment of the present application; 
         FIG. 9  is a second schematic diagram of structural composition of the load control apparatus provided by the embodiment of the present application; 
         FIG. 10  is a third schematic diagram of structural composition of the load control apparatus provided by the embodiment of the present application; 
         FIG. 11  is a fourth structural diagram of structural composition of the load control apparatus provided by the embodiment of the present application; 
         FIG. 12  is a schematic structural diagram of a communication device provided by an embodiment of the present application; 
         FIG. 13  is a schematic structural diagram of a chip of an embodiment of the present application; 
         FIG. 14  is a schematic block diagram of a communication system provided by an embodiment of the present application. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The technical solutions in embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are a part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort shall fall within the protection scope of the present application. 
     The technical solutions of the embodiments of the present application can 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 General Packet Radio Service (GPRS), a Long Term Evolution (LTE) system, an LTE Frequency Division Duplex (FDD) system, an LTE Time Division Duplex (TDD), a Universal Mobile Telecommunication System (UMTS), a Worldwide interoperability for Microwave Access (WiMAX) communication system or a 5G system, etc. 
     Exemplarily, a communication system  100  to which the embodiments of the present application are applied is shown in  FIG. 1 . The communication system  100  can include a network device  110 , and the network device  110  can be a device that communicates with a terminal  120  (or called a communication terminal or a terminal). The network device  110  can provide communication coverage for a specific geographic area, and can communicate with terminals located in the coverage area. Optionally, the network device  110  may be a base station (Base Transceiver Station, BTS) in a GSM system or a CDMA system, or a base station (NodeB, NB) in a WCDMA system, or an evolutional base station (Evolutional Node B, eNB or eNodeB) in an LTE system, or a wireless controller in a Cloud Radio Access Network (CRAN); or the network device may be a mobile switching center, a relay station, an access point, a vehicle-mounted device, a wearable device, a hub, a switch, a bridge, a router, a network side device in a 5G network, or a network device in a future evolutional Public Land Mobile Network (PLMN), etc. 
     The communication system  100  also includes at least one terminal  120  located within the coverage area of the network device  110 . The “terminal” as used herein includes, but is not limited to, connections via a wired line, such as via a Public Switched Telephone Network (PSTN), a Digital Subscriber Line (DSL), a digital cable, and a direct cable connections; and/or via another data connection/network; and/or via a wireless interface, for example, for a cellular network, a Wireless Local Area Network (WLAN), a digital TV network such as a DVB-H network, a satellite network, an AM-FM broadcast transmitter; and/or via an apparatus of another terminal, configured to receive/send communication signals; and/or via an Internet Of Things (IoT) device. A terminal configured to communicate through a wireless interface may be referred to as a “wireless communication terminal”, a “wireless terminal” or a “mobile terminal”. Examples of the mobile terminal include, but are not limited to, a satellite or a cellular phone; a Personal Communications System (PCS) terminal that can combine a cellular radio phone with data processing, fax, and data communication capabilities; an PDA that can include a radio phone, a pager, an Internet/intranet access, a Web browser, a memo pad, a calendar and/or a Global Positioning System (GPS) receiver; and a conventional laptop and/or palmtop receiver or other electronic apparatuses including a radio telephone transceiver. The terminal can refer to an access terminal, a User Equipment (UE), a user unit, a user station, a mobile radio station, a mobile station, 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 can 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 with a wireless communication function, or other processing devices connected to wireless modem and having a wireless communication function, an in-vehicle device, a wearable device, a terminal in the 5G network, or a terminal in the future evolutional PLMN, etc. 
     Optionally, a Device to Device (D2D) communication may be performed between terminals  120 . 
     Optionally, the 5G system or the 5G network may also be referred to as a New Radio (NR) system or an NR network. 
       FIG. 1  exemplarily shows one network device and two terminals. Optionally, the communication system  100  may include multiple network devices and the coverage of each network device may include other numbers of terminals, which are not limited in the embodiments of the present application. 
     Optionally, the communication system  100  may also include other network entities, such as a network controller, a mobility management entity, which is not limited in the embodiments of the present application. 
     It should be understood that the device with a communication function in the network/system in the embodiments of the present application may be referred to as a communication device. Taking the communication system  100  shown in  FIG. 1  as an example, the communication device may include the network device  110  and the terminal  120  with the communication function, and the network device  110  and the terminal  120  may be a specific device described above, which will not be repeated here. The communication device may also include other devices in the communication system  100 , for example, other network entities such as a network controller, a mobility management entity, etc., which are not limited in the embodiments of the present application. 
     It should be understood that the terms “system” and “network” are often used interchangeably herein. The term “and/or” herein is only an association relationship for describing associated objects, and means that there can be three types of relationships. For example, the expression “A and/or B” may indicate three cases: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character “/” herein generally indicates that the associated objects before and after the character are in an “or” relationship. 
     In order to meet people&#39;s pursuit of service rate, delay, high-speed mobility and energy efficiency, as well as diversity and complexity of services in future life, the 3rd Generation Partnership Project (3GPP) international standard organization began to develop the 5th Generation (5G) mobile communication technology. 
     The air interface part of the 5G mobile communication technology is called New Radio (NR). In early deployment of NR, it is difficult to achieve complete NR coverage. Therefore, a typical network coverage is a combination of Long Term Evolution (LTE) coverage and NR coverage. In addition, in order to protect early investment on LTE by mobile operators, a working mode of tight interworking between LTE and NR is proposed. Of course, an NR cell can also be deployed independently. In addition, since each NR cell is beam-operated, one cell has multiple beams. 
     The technical solutions of the embodiments of the present disclosure are mainly applied to the 5G mobile communication system. Of course, the technical solutions of the embodiments of the present disclosure are not limited to the 5G mobile communication system, but can also be applied to other types of mobile communication systems. Main application scenarios in the 5G mobile communication system are described in the following: 
     1) eMBB scenario: eMBB targets obtaining multimedia content, services and data by users, and service demand thereof is growing very rapidly. Since eMBB may be deployed in different scenarios, such as indoor, in an urban area, in a rural area, etc., service capabilities and requirements thereof vary greatly. Therefore, a service has to be analyzed in combination with a specific deployment scenario. 
     2) URLLC scenario: typical applications of URLLC include: industrial automation, power automation, telemedicine operation, traffic safety assurance, etc. 
     3) mMTC scenario: typical features of mMTC include: high connection density, small data volume, delay-insensitive services, low cost of modules, long service life, etc. 
     A random access procedure is first required when a UE accesses a network and obtains an RRC connection. Refer to  FIG. 2 ,  FIG. 2  is a flowchart of a four-step random access procedure, including the following steps: 
     1. The UE sends, to a gNB, an MSG1: a Random Access Preamble. 
     Specifically, the UE selects a PRACH resource and sends a selected Preamble on the PRACH resource. Here, there are a total of 64 Preambles, and each Preamble corresponds to an index, and a value of the index ranges from 0 to 63. 
     2. The gNB sends, to the UE, an MSG2: a Random Access Response (RAR). 
     Specifically, the gNB replies to the MSG1 and sends a random access response to the UE, and the UE calculates, according to the PRACH resource for sending the Preamble, a random access-radio network temporary identifier (RA-RNTI) used to scramble scheduling information of the MSG2. A Media Access Control (MAC) layer data format of a RAR is shown in  FIG. 3( a ) ,  FIG. 3( b ) ,  FIG. 3( c )  and  FIG. 3( d ) , among which  FIG. 3( a )  is a format of an E/T/R/R/BI MAC subheader,  FIG. 3( b )  is a format of an E/T/RAPID MAC subheader,  FIG. 3( c )  is a format of a Media Access Control Protocol Data Unit (MAC PDU) (including MAC RARs), and  FIG. 3( d )  is a schematic diagram of a MAC RAR. 
     3. The UE sends, to the gNB, an MSG3: scheduled transmission. 
     Specifically, in the MSG2, the network side will allocate an uplink resource to the UE for sending the MSG3, and the UE sends the MSG3 on the uplink resource (UL grant) allocated by the network side. 
     4. The gNB sends, to the UE, an MSG4: contention resolution. 
     In order to shorten delay of the random access procedure and quickly enter the network side to start a service, a two-step random access procedure is proposed. In the two-step random access procedure, an MSG1 and an MSG3 are sent at the same time or almost at the same time (the MSG3 can be sent without waiting for an MSG2 here), and an MSG2 and an MSG4 are sent together (one PDSCH transmission or two PDSCH transmissions). 
     In the two-step random access procedure, resources used to send the MSG3 are pre-configured, and the pre-configured resources are limited. In order to avoid resource waste, the two-step random access procedure will not configure many resources. On the other hand, the two-step random access procedure should ensure that a UE with a high delay requirement can use MSG3 resources normally. Therefore, when many users use the two-step random access procedure which leads to a relatively high resource load of the two-step random access procedure, conflict probability will be increased and access delay will be further expanded, so it is necessary to perform load control on the two-step random access procedure. 
       FIG. 4  is a first schematic flowchart  1  of a load control method provided by an embodiment of the present application. As shown in  FIG. 4 , the load control method includes the following step: 
     Step  401 : a network device sends a system broadcast message, where the system broadcast message includes a first configuration parameter, and the first configuration parameter is used to control whether a terminal performs a two-step random access procedure. 
     In the embodiment of the present application, the network device may be a base station, such as a gNB in 5G or an eNB in 4G. 
     In the embodiment of the present application, the network device sends the system broadcast message by broadcasting. Here, the system broadcast message includes the first configuration parameter, and the first configuration parameter is used to control whether the terminal performs the two-step random access procedure. 
     In the embodiment of the present application, the first configuration parameter includes second indication information and a first control parameter, where: 
     the second indication information is used to indicate whether the terminal is capable of performing the two-step random access procedure; 
     the first control parameter is used to judge whether the terminal performs a switching from the two-step random access procedure to a four-step random access procedure, in a case that the second indication information indicates that the terminal is capable of performing the two-step random access procedure. 
     In an implementation, the second indication information includes a first bitmap. Each bit in the first bitmap corresponds to an Access Control (AC) value, and a value of the bit is used to indicate whether a terminal of the AC value corresponding to this bit is capable of performing the two-step random access procedure. 
     For example: the first bitmap is an AC bitmap, and each bit in the AC bitmap corresponds to a control of using the 2-step RACH for a UE of an AC value. For example, 10101 indicates control information of using the 2-step RACH by UEs of AC=11 to 15, then terminals of AC=11, 13, and 15 are capable of performing the 2-step RACH when accessing. 
     In an implementation, the first control parameter includes a first random number; 
     the judging whether the terminal performs the switching from the two-step random access procedure to the four-step random access procedure includes: 
     if a second random number generated by the terminal is greater than or equal to the first random number, determining that the terminal performs the switching from the two-step random access procedure to the four-step random access procedure; 
     if the second random number generated by the terminal is smaller than the first random number, determining that the terminal performs the two-step random access procedure. 
     For example: the gNB broadcasts a random number in system broadcast, and the number is between 0 and 1. The UE randomly generates a number from 0 to 1 and compares the same with the random number configured in the system broadcast. If the number generated by the UE is greater than the number in the system broadcast, then the UE falls back to the 4 step RACH, otherwise continues performing the 2 step RACH. 
     In an implementation, the network device detects that a load of a PRACH used to perform the two-step random access procedure exceeds a first threshold, then the network device sends first indication information to the terminal, where the first indication information is used to instruct the terminal to judge whether to perform the switching from the two-step random access procedure to the four-step random access procedure. Here, when the network side detects that the load of the PRACH of the 2-step RACH is relatively high, the network side sends the first indication information to the UE to instruct the UE to judge whether to perform a fallback from the 2-step RACH to the 4-step RACH. 
     In the embodiment of the present application, the network device may send the first indication information to the terminal in any of the following two manners: 
     Manner One: 
     The network device carries the first indication information in a random access response message sent to the terminal. 
     Further, a MAC PDU in the random access response message carries the first indication information. Here, the MAC PDU in the random access response message may be referred to as a RAR MAC PDU, and the RAR MAC PDU carries the first indication information for instructing the UE to judge whether to perform the fallback from the 2 step RACH to the 4 step RACH. 
     Manner Two: 
     The network device carries the first indication information in a paging message or paging Downlink Control Information (DCI) sent to the terminal. 
     Here, the first indication information is carried in the paging message, or the first indication information is carried in the paging DCI, for instructing the UE to judge whether to perform the fallback from the 2 step RACH to the 4 step RACH. 
     In the embodiment of the present application, the AC value of the UE can also instruct the UE to judge whether to perform the fallback from the 2 step RACH to the 4 step RACH. For example, a bit corresponding to the AC value of the UE is determined to be 1 based on the AC bitmap, which represents that the UE is capable of performing the 2 step RACH, that is, the AC value instructs the UE to judge whether to perform the fallback from the 2 step RACH to the 4 step RACH. If the UE receives the first indication information sent by the network device, and the AC value of the UE also indicates that it is needed to judge whether to perform the fallback from the 2 step RACH to the 4 step RACH, the UE judges whether to perform the 2 step RACH according to the random number in the system broadcast. For example, the UE randomly generates a number from 0 to 1 and compares the same with the random number configured in the system broadcast. If the number generated by the UE is greater than the number in the system broadcast, then the UE falls back to the 4 step RACH, otherwise continues performing the 2 step RACH. 
     It should be noted that each user is randomly assigned an AC value from 0 to 9. The AC value is stored in a SIM card. Some special users may have one or more AC values from 11 to 15, which are also stored in the SIM card. A user having an AC value of 11 to 15 generally has a higher priority. However, the size of the AC value does not represent the order of priority. 
       FIG. 5  is a second schematic flowchart of a load control method provided by an embodiment of the present application. As shown in  FIG. 5 , the load control method includes the following step: 
     Step  501 : a terminal receives a system broadcast message sent by a network device, where the system broadcast message includes a first configuration parameter; the terminal determines, based on the first configuration parameter, whether to perform a two-step random access procedure. 
     In the embodiment of the present application, the network device may be a base station, such as a gNB in 5G or an eNB in 4G. 
     In the embodiment of the present application, the network device sends the system broadcast message by broadcasting. Here, the system broadcast message includes the first configuration parameter, and the first configuration parameter is used to control whether the terminal performs the two-step random access procedure. 
     In the embodiment of the present application, the first configuration parameter includes second indication information and a first control parameter, where: 
     the second indication information is used to indicate whether the terminal is capable of performing the two-step random access procedure; 
     the first control parameter is used to judge whether the terminal performs a switching from the two-step random access procedure to a four-step random access procedure, in a case that the second indication information indicates that the terminal is capable of performing the two-step random access procedure. 
     In an implementation, the second indication information includes a first bitmap. Each bit in the first bitmap corresponds to an AC value, and a value of the bit is used to indicate whether a terminal of the AC value corresponding to this bit is capable of performing the two-step random access procedure. 
     For example: the first bitmap is an AC bitmap, and each bit in the AC bitmap corresponds to a control of using the 2-step RACH control for a UE of an AC value. For example, 10101 indicates control information of using the 2-step RACH by UEs of AC=11 to 15, then terminals of AC=11, 13, and 15 are capable of performing the 2-step RACH when accessing. 
     In an implementation, the first control parameter includes a first random number; 
     the judging whether the terminal performs the switching from the two-step random access procedure to the four-step random access procedure includes that: if the terminal receives first indication information sent by the network device, the terminal determines, based on the first configuration parameter, whether to perform the two-step random access procedure. Further, if a second random number generated by the terminal is greater than or equal to the first random number, then it is determined that the terminal performs the switching from the two-step random access procedure to the four-step random access procedure; if the second random number is smaller than the first random number, then it is determined that the terminal performs the two-step random access procedure. 
     For example: the gNB broadcasts a random number in system broadcast, and the number is between 0 and 1. The UE randomly generates a number from 0 to 1 and compares the same with the random number configured in the system broadcast. If the number generated by the UE is greater than the number in the system broadcast, then the UE falls back to the 4 step RACH, otherwise continues performing the 2 step RACH. 
     In an implementation, the terminal receives first indication information sent by the network device, where the first indication information is used to instruct the terminal to determine whether to perform the switching from the two-step random access procedure to the four-step random access procedure. Here, when the network side detects that a load of a PRACH of the 2-step RACH is relatively high, the network side sends the first indication information to the UE to instruct the UE to determine whether to perform a fallback from the 2-step RACH to the 4-step RACH. 
     In the embodiment of the present application, the terminal may obtain the first indication information in any of the following two manners: 
     Manner One: 
     The terminal obtains the first indication information from a random access response message sent by the network device. 
     Here, a MAC PDU in the random access response message may be referred to as a RAR MAC PDU, and the RAR MAC PDU carries the first indication information for instructing the UE to judge whether to perform the fallback from the 2 step RACH to the 4 step RACH. 
     Manner Two: 
     The terminal obtains the first indication information from a paging message or paging DCI sent by the network device. 
     Here, the first indication information is carried in the paging message, or the first indication information is carried in the paging DCI, for instructing the UE to judge whether to perform the fallback from the 2 step RACH to the 4 step RACH. 
     In the embodiment of the present application, the AC value of the UE can also instruct the UE to judge whether to perform the fallback from the 2 step RACH to the 4 step RACH. For example, a bit corresponding to the AC value of the UE is determined to be 1 based on the AC bitmap, which represents that the UE is capable of performing the 2 step RACH, that is, the AC value instructs the UE to judge whether to perform the fallback from the 2 step RACH to the 4 step RACH. If the UE receives the first indication information sent by the network device, and the AC value of the UE also indicates that it is needed to judge whether to perform the fallback from the 2 step RACH to the 4 step RACH, the UE judges whether to perform the 2 step RACH according to the random number in the system broadcast. For example, the UE randomly generates a number from 0 to 1 and compares the same with the random number configured in the system broadcast. If the number generated by the UE is greater than the number in the system broadcast, then the UE falls back to the 4 step RACH, otherwise continues performing the 2 step RACH. 
     It should be noted that each user is randomly assigned an AC value from 0 to 9. The AC value is stored in a SIM card. Some special users may have one or more AC values from 11 to 15, which are also stored in the SIM card. A user having an AC value of 11 to 15 generally has a higher priority. However, the size of the AC value does not represent the order of priority. 
       FIG. 6  is a third schematic flowchart of a load control method provided by an embodiment of the present application. As shown in  FIG. 6 , the load control method includes the following step: 
     Step  601 : a network device detects that a load of a PRACH used to perform a two-step random access procedure exceeds a first threshold, then the network device sends first indication information to a terminal, where the first indication information instructs the terminal to perform a switching from the two-step random access procedure to a four-step random access procedure. 
     In the embodiment of the present application, the network device may be a base station, such as a gNB in 5G or an eNB in 4G. 
     In the embodiment of the present application, when the network side detects that the load of the PRACH of the 2-step RACH is relatively high, the network side sends the first indication information to a UE to instruct the UE to perform a fallback from the 2-step RACH to the 4-step RACH. 
     In the embodiment of the present application, the network device may send the first indication information to the terminal in any of the following two manners: 
     Manner One: 
     The network device carries the first indication information in a random access response message sent to the terminal. 
     Further, a MAC PDU in the random access response message carries the first indication information. Here, the MAC PDU in the random access response message may be referred to as a RAR MAC PDU, and the RAR MAC PDU carries the first indication information for instructing the UE to perform the fallback from the 2 step RACH to the 4 step RACH. 
     Manner Two: 
     The network device carries the first indication information in a paging message or paging DCI sent to the terminal. 
     Here, the first indication information is carried in the paging message, or the first indication information is carried in the paging DCI, for instructing the UE to perform the fallback from the 2 step RACH to the 4 step RACH. 
       FIG. 7  is a fourth schematic flowchart of a load control method provided by an embodiment of the present application. As shown in  FIG. 7 , the load control method includes the following step: 
     Step  701 : a terminal receives first indication information sent by a network device; the terminal determines, based on the first indication information, to perform a switching from a two-step random access procedure to a four-step random access procedure. 
     In the embodiment of the present application, the network device may be a base station, such as a gNB in 5G or an eNB in 4G. 
     Here, when the network side detects that a load of a PRACH of the 2 step RACH is relatively high, the network side sends the first indication information to a UE to instruct the UE to perform a fallback from the 2 step RACH to the 4 step RACH. 
     In the embodiment of the present application, the terminal may obtain the first indication information in any of the following two manners: 
     Manner One: 
     The terminal obtains the first indication information from a random access response message sent by the network device. 
     Further, a MAC PDU in the random access response message carries the first indication information. Here, the MAC PDU in the random access response message may be referred to as a RAR MAC PDU, and the RAR MAC PDU carries the first indication information, for instructing the UE to perform the fallback from the 2 step RACH to the 4 step RACH. 
     Manner Two: 
     The terminal obtains the first indication information from a paging message or paging DCI sent by the network device. 
     Here, the first indication information is carried in the paging message, or the first indication information is carried in the paging DCI, for instructing the UE to perform the fallback from the 2 step RACH to the 4 step RACH. 
     In an implementation, the terminal performs the four-step random access procedure when initiating random access again after the current two-step random access procedure ends. 
       FIG. 8  is a first schematic diagram of structural composition of a load control apparatus provided by an embodiment of the present application, which is applied to a network device, such as a base station. As shown in  FIG. 8 , the apparatus includes: 
     a first sending unit  801 , configured to send a system broadcast message, where the system broadcast message includes a first configuration parameter, and the first configuration parameter is used to control whether a terminal performs a two-step random access procedure. 
     In an implementation, the apparatus further includes: 
     a detecting unit  802 , configured to detect that a load of a PRACH used to perform the two-step random access procedure exceeds a first threshold; 
     a second sending unit  803 , configured to send first indication information to the terminal, where the first indication information is used to instruct the terminal to judge whether to perform a switching from the two-step random access procedure to a four-step random access procedure. 
     In an implementation, the second sending unit  803  is configured to carry the first indication information in a random access response message sent to the terminal. 
     In an implementation, a MAC PDU in the random access response message carries the first indication information. 
     In an implementation, the second sending unit  803  is configured to carry the first indication information in a paging message or paging DCI sent to the terminal. 
     In an implementation, the first configuration parameter includes second indication information and a first control parameter, where, 
     the second indication information is used to indicate whether the terminal is capable of performing the two-step random access procedure; 
     the first control parameter is used to judge whether the terminal performs the switching from the two-step random access procedure to the four-step random access procedure, in a case that the second indication information indicates that the terminal is capable of performing the two-step random access procedure. 
     In an implementation, the second indication information includes a first bitmap. Each bit in the first bitmap corresponds to an AC value, and a value of the bit is used to indicate whether a terminal of the AC value corresponding to this bit is capable of performing the two-step random access procedure. 
     In an implementation, the first control parameter includes a first random number; 
     the judging whether the terminal performs the switching from the two-step random access procedure to the four-step random access procedure includes: 
     if a second random number generated by the terminal is greater than or equal to the first random number, determining that the terminal performs the switching from the two-step random access procedure to the four-step random access procedure; 
     if the second random number generated by the terminal is smaller than the first random number, determining that the terminal performs the two-step random access procedure. 
     Those skilled in the art should understand that the relevant description of the foregoing load control apparatus in the embodiments of the present application can be understood with reference to the relevant description of the load control method in the embodiments of the present application. 
       FIG. 9  is a second schematic diagram of structural composition of a load control apparatus provided by an embodiment of the present application, which is applied to a terminal. As shown in  FIG. 9 , the apparatus includes: 
     a first receiving unit  901 , configured to receive a system broadcast message sent by a network device, where the system broadcast message includes a first configuration parameter; 
     a determining unit  902 , configured to determine, based on the first configuration parameter, whether to perform a two-step random access procedure. 
     In an implementation, the apparatus further includes: 
     a second receiving unit  903 , configured to receive first indication information sent by the network device, where the first indication information is used to instruct the terminal to determine whether to perform a switching from the two-step random access procedure to a four-step random access. 
     In an implementation, the second receiving unit  903  is configured to obtain the first indication information from a random access response message sent by the network device. 
     In an implementation, a MAC PDU in the random access response message carries the first indication information. 
     In an implementation, the second receiving unit  903  is configured to obtain the first indication information from a paging message or paging DCI sent by the network device. 
     In an embodiment, the first configuration parameter includes second indication information and a first control parameter, where, 
     the second indication information is used to indicate whether the terminal is capable of performing the two-step random access procedure; 
     the first control parameter is used to judge whether the terminal performs the switching from the two-step random access procedure to the four-step random access procedure, in a case that the second indication information indicates that the terminal is capable of performing the two-step random access procedure. 
     In an implementation, the second indication information includes a first bitmap. Each bit in the first bitmap corresponds to an AC value, and a value of the bit is used to indicate whether a terminal of the AC value corresponding to this bit is capable of performing the two-step random access procedure. 
     In an implementation, the first control parameter includes a first random number; 
     the determining unit  902  is configured to, if the first indication information sent by the network device is received, determine, based on the first configuration parameter, whether to perform the two-step random access procedure. 
     In an implementation, the determining unit  902  is configured to: determine that the terminal performs the switching from the two-step random access procedure to the four-step random access procedure, if a second random number generated by the terminal is greater than or equal to the first random number; determine that the terminal performs the two-step random access procedure, if the second random number generated by the terminal is smaller than the first random number. 
     Those skilled in the art should understand that the relevant description of the foregoing load control apparatus in the embodiments of the present application can be understood with reference to the relevant description of the load control method in the embodiments of the present application. 
       FIG. 10  is a third schematic diagram of structural composition of a load control apparatus provided by an embodiment of the present application, which is applied to a network device, such as a base station. As shown in  FIG. 10 , the apparatus includes: 
     a detecting unit  1001 , configured to detect that a load of a PRACH used to perform a two-step random access procedure exceeds a first threshold; 
     a sending unit  1002 , configured to send first indication information to a terminal, where the first indication information instructs the terminal to perform a switching from the two-step random access procedure to a four-step random access procedure. 
     In an implementation, the sending unit  1002  is configured to carry the first indication information in a random access response message sent to the terminal. 
     In an implementation, the carrying the first indication information in the random access response message includes: 
     carrying the first indication information in a MAC PDU in the random access response message. 
     In an implementation, the sending unit  1002  is configured to carry the first indication information in a paging message or paging DCI sent to the terminal. 
     Those skilled in the art should understand that the relevant description of the foregoing load control apparatus in the embodiments of the present application can be understood with reference to the relevant description of the load control method in the embodiments of the present application. 
       FIG. 11  is a fourth schematic diagram of structural composition of a load control apparatus provided by an embodiment of the present application, which is applied to a terminal. As shown in  FIG. 11 , the apparatus includes: 
     a receiving unit  1101 , configured to receive first indication information sent by a network device; 
     a determining unit  1002 , configured to determine, based on the first indication information, a switching from a two-step random access procedure to a four-step random access procedure. 
     In an implementation, the receiving unit  1101  is configured to obtain the first indication information from a random access response message sent by the network device. 
     In an implementation, a MAC PDU in the random access response message carries the first indication information. 
     In an implementation, the receiving unit  1101  is configured to obtain the first indication information from a paging message or paging DCI sent by the network device. 
     In an implementation, the apparatus further includes: 
     a random access unit  1103 , configured to perform the four-step random access procedure when initiating random access again after the current two-step random access procedure ends. 
     Those skilled in the art should understand that the relevant description of the foregoing load control apparatus in the embodiments of the present application can be understood with reference to the relevant description of the load control method in the embodiments of the present application. 
       FIG. 12  is a schematic structural diagram of a communication device  600  provided by an embodiment of the present application. The communication device may be a network device or a terminal. The communication device  600  shown in  FIG. 12  includes a processor  610 , and the processor  610  can call and run a computer program from a memory to implement the methods in embodiments of the present application. 
     Optionally, as shown in  FIG. 12 , the communication device  600  can further include a memory  620 . The processor  610  can call and run a computer program from the memory  620  to implement the methods in the embodiments of the present application. 
     The memory  620  may be a separate device independent of the processor  610 , or may be integrated into the processor  610 . 
     Optionally, as shown in  FIG. 12 , the communication device  600  can further include a transceiver  630 , and the processor  610  can control the transceiver  630  to communicate with other devices. Specifically, the transceiver may send information or data to other devices, or receive information or data sent by other devices. 
     The transceiver  630  may include a transmitter and a receiver. The transceiver  630  may further include an antenna, and the number of the antennas may be one or more. 
     Optionally, the communication device  600  may specifically be a network device of embodiments of the present application, and the communication device  600  may implement corresponding processes implemented by the network device in respective methods of the embodiments of the application. For brevity, details are not repeated here. 
     Optionally, the communication device  600  may specifically be a mobile terminal/terminal according to embodiments of the present application, and the communication device  600  may implement corresponding processes implemented by the mobile terminal/terminal in respective methods of the embodiments of the present application. For brevity, details are not repeated here. 
       FIG. 13  is a schematic structural diagram of a chip of an embodiment of the present application. The chip  700  shown in  FIG. 13  includes a processor  710 , and the processor  710  can call and run a computer program from a memory to implement the methods in embodiments of the present application. 
     Optionally, as shown in  FIG. 13 , the chip  700  can further include a memory  720 . The processor  710  can call and run a computer program from the memory  720  to implement the methods in the embodiments of the present application. 
     The memory  720  may be a separate device independent of the processor  710 , or may be integrated into the processor  710 . 
     Optionally, the chip  700  can further include an input interface  730 . The processor  710  can control the input interface  730  to communicate with other devices or chips, and specifically to obtain information or data sent by other devices or chips. 
     Optionally, the chip  700  can further include an output interface  740 . The processor  710  can control the output interface  740  to communicate with other devices or chips, and specifically to output information or data to other devices or chips. 
     Optionally, the chip can be applied to the network device in the embodiments of the present application, and the chip can implement corresponding processes implemented by the network device in respective methods of the embodiments of the present application. For brevity, details are not repeated here. 
     Optionally, the chip can be applied to the mobile terminal/terminal in the embodiments of the present application, and the chip can implement corresponding processes implemented by the mobile terminal/terminal in respective methods of the embodiments of the present application. For brevity, details are not repeated here. 
     It should be understood that the chip mentioned in the embodiments of the present application may also be referred to as a system-level chip, a system-on-chip, a chip system, an SoC chip, or the like. 
       FIG. 14  is a schematic block diagram of a communication system  900  provided by an embodiment of the present application. As shown in  FIG. 14 , the communication system  900  includes a terminal  910  and a network device  920 . 
     The terminal  910  can be used to implement corresponding functions implemented by the terminal in the foregoing methods, and the network device  920  can be used to implement corresponding functions implemented by the network device in the foregoing methods. For brevity, details are not repeated here. 
     It should be understood that the processor of the embodiments of the present application may be an integrated circuit chip with signal processing capability. In the implementation process, the steps of the foregoing method embodiments can be completed by an integrated logic circuit in hardware of the processor or by instructions in the form of software. The above-mentioned processor may be a general-purpose processor, a Digital Signal Processor (DSP), an Application Specific 
     Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programming logic devices, discrete gates or transistor logic devices, discrete hardware components, which can implement or perform the methods, steps, and logical block diagrams disclosed in the embodiments of the present application. The general-purpose processor may be a microprocessor, or the processor may also be any conventional processor or the like. The steps of the methods disclosed in the embodiments of the present application can be directly embodied as being executed and completed by a hardware decoding processor, or being executed and completed by a combination of hardware and software modules in a decoding processor. The software modules can be located in a mature storage medium in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, an electrically erasable programmable memory, a register, etc. The storage medium is located in a memory, and the processor reads information in the memory and completes the steps of the above methods in combination with hardware thereof. 
     It can be understood that the memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. The non-volatile memory may be a read-only memory (Read-Only Memory, ROM), a programmable read-only memory (Programmable ROM, PROM), an erasable programmable read-only memory (Erasable PROM, EPROM), and an electrically erasable programmable read-only memory (Electrically EPROM, EEPROM) or a flash memory. The volatile memory may be a random access memory (Random Access Memory, RAM), which is used as an external cache. By way of exemplary but not restrictive description, many forms of RAMs are available, such as a static random access memory (Static RAM, SRAM), a dynamic random access memory (Dynamic RAM, DRAM), a synchronous dynamic random access memory (Synchronous DRAM, SDRAM), a double data rate synchronous dynamic random access memory (Double Data Rate SDRAM, DDR SDRAM), an enhanced synchronous dynamic random access memory (Enhanced SDRAM, ESDRAM), a synchronous link dynamic random access memory (Synchlink DRAM, SLDRAM)) and a direct rambus random access memory (Direct Rambus RAM, DR RAM). It should be noted that the memories of the systems and methods described herein are intended to include, but are not limited to, these and any other suitable types of memories. 
     An embodiment of the present application also provides a computer-readable storage medium for storing a computer program. 
     Optionally, the computer-readable storage medium can be applied to the network device in the embodiments of the present application, and the computer program causes a computer to execute corresponding processes implemented by the network device in respective methods of the embodiments of the present application. For brevity, details are not repeated here. 
     Optionally, the computer-readable storage medium can be applied to the mobile terminal/terminal in the embodiments of the present application, and the computer program causes the computer to execute corresponding processes implemented by the mobile terminal/terminal in respective methods of the embodiments of the present application. For brevity, details are not repeated here. 
     An embodiment of the present application also provides a computer program product, including computer program instructions. 
     Optionally, the computer program product can be applied to the network device in the embodiments of the present application, and the computer program instructions cause a computer to execute corresponding processes implemented by the network device in respective methods of the embodiments of the present application. For brevity, details are not repeated here. 
     Optionally, the computer program product can be applied to the mobile terminal/terminal in the embodiments of the present application, and the computer program instructions cause the computer to execute corresponding processes implemented by the mobile terminal/terminal in respective methods of the embodiments of the present application. For brevity, details are not repeated here. 
     An embodiment of the present application also provides a computer program. 
     Optionally, the computer program can be applied to the network device in the embodiments of the present application. When the computer program runs on a computer, the computer is caused to execute corresponding processes implemented by the network device in respective methods of the embodiments of the present application. For brevity, details are not repeated here. 
     Optionally, the computer program can be applied to the mobile terminal/terminal in the embodiments of the present application. When the computer program runs on the computer, the computer is caused to execute corresponding processes implemented by the mobile terminal/terminal in respective methods of the embodiments of the present application. For brevity, details are not repeated here. 
     A person of ordinary skill in the art may realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed by hardware or software depends on specific applications and design constraints for the technical solution. Those skilled persons can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of the present application. 
     Those skilled in the art can clearly understand that, for convenience and concise description, the corresponding processes in the foregoing method embodiments may be referred to for the specific working processes of the above-described system, apparatus, and unit, and details are not repeated here. 
     It should be understood that the system, apparatus, and method disclosed in the several embodiments provided in the present application may be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For example, the division of the units is only a logical function division, and there may be other divisions in actual implementation. For example, multiple units or components may be combined or may be integrated into another system, or some features can be ignored or not implemented. In addition, the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, apparatuses or units, and may be in electrical, mechanical or other forms. 
     The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the solutions of the embodiments. 
     In addition, the functional units in the various embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units may be integrated into one unit. 
     If the functions are implemented in the form of software functional units and sold or used as an independent product, they can be stored in a computer readable storage medium. Based on this understanding, the essence, or the part that contributes to the prior art, or part, of the technical solutions of the present application can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions used to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, an optical disk, or other media that can store program codes. 
     The above description is only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.