Patent Publication Number: US-2017366922-A1

Title: Method and apparatus for setting coverage level of terminal

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Application No. PCT/CN2015/073662, filed on Mar. 4, 2015, the disclosure of which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present invention relates to the user terminal field, and in particular, to a method and an apparatus for setting a coverage level of a user terminal, and a system. 
     BACKGROUND 
     Machine type communication can be widely applied to fields, such as smart metering, medical tests, logistics detection, and fire monitoring. In machine type communication, a terminal (UE) estimates a coverage level of the user terminal, and uploads an estimated result to a communications device (for example, a base station). Then, the base station sends a signal to the user terminal according to a sending policy for the coverage level, so that quality of communication between the base station and the user terminal can meet a requirement. However, estimation by the user terminal usually has a deviation, and the signal sent by the communications device according to the estimated result of the user terminal usually cannot meet an actual communication requirement. 
     SUMMARY 
     Embodiments of the present invention provide a method and an apparatus for setting a coverage level of user terminal, so as to more accurately set the coverage level of the user terminal in a communication environment, and better meet an actual communication requirement. 
     According to a first aspect, an embodiment of the present invention provides a method for setting a coverage level of a user terminal (It can also be expressed as user equipment,UE for short, The UE hereinafter refer to user equipment), including: receiving corresponding information from a communications device, where the corresponding information indicates a correspondence between at least one sending resource and at least one coverage level; receiving, from the communications device, at least one segment of control information sent by using the at least one sending resource, where each segment of control information in the at least one segment of control information is sent by using one sending resource in the at least one sending resource; parsing the at least one segment of control information to obtain content included in the at least one segment of control information; and setting, according to the corresponding information if content included in one segment of control information in the at least one segment of control information includes information indicating an identity of the user terminal, a coverage level of the user terminal to a first coverage level that is in the at least one coverage level and that is corresponding to a sending resource by using which the one segment of control information is sent. 
     In a first possible implementation manner of the first aspect, the setting, according to the corresponding information if content included in one segment of control information in the at least one segment of control information includes information indicating an identity of the user terminal, a coverage level of the user terminal to a first coverage level that is in the at least one coverage level and that is corresponding to a sending resource by using which the one segment of control information is sent includes: setting the coverage level of the user terminal to the first coverage level according to the corresponding information if the content included in the one segment of control information in the at least one segment of control information includes the information indicating the identity of the user terminal and at least one of the following information: uplink/downlink scheduling information, a request for aperiodic channel quality indicator reporting, a change indication and an uplink power control command of a multicast control channel, or an acknowledgment/negative acknowledgment ACK/NACK feedback on random access channel RACH resource allocation and uplink data. 
     With reference to the first aspect, or the first possible implementation manner of the first aspect, in a second possible implementation manner, the at least one segment of control information includes several segments of control information; and the receiving at least one segment of control information sent by using the at least one sending resource includes: periodically receiving the several segments of control information; and the parsing the at least one segment of control information to obtain content included in the at least one segment of control information includes: periodically parsing the several segments of control information to obtain content included in the several segments of control information. 
     With reference to any one of the first aspect, or the first and the second possible implementation manners of the first aspect, in a third possible implementation manner, before the receiving, from the communications device, at least one segment of control information sent by using the at least one sending resource, the method further includes: setting the coverage level of the user terminal to a second coverage level in the at least one coverage level. 
     With reference to the third possible implementation manner of the first aspect, in a fourth possible implementation manner, the first coverage level is different from the second coverage level. 
     With reference to the fourth possible implementation manner of the first aspect, in a fifth possible implementation manner, the first coverage level is one level or several higher than the second coverage level. 
     With reference to any one of the first aspect, or the first to the fifth possible implementation manners of the first aspect, in a sixth possible implementation manner, the receiving, from the communications device, at least one segment of control information sent by using the at least one sending resource includes: detecting quality of data transmission between the communications device and the user terminal; and if the quality is lower than a quality threshold, receiving, from the communications device, the at least one segment of control information sent by using the at least one sending resource. 
     With reference to any one of the first aspect, or the first to the sixth possible implementation manners of the first aspect, in a seventh possible implementation manner, the information indicating the identity of the user terminal includes a user terminal identity existing in cyclic redundancy check code in a form of implicit code. 
     According to a second aspect, an embodiment of the present invention provides a method for indicating a coverage level for a user terminal (UE), including: sending corresponding information to the user terminal, where the corresponding information indicates a correspondence between at least one sending resource and at least one coverage level; determining a coverage level of the user terminal as a first coverage level in the at least one coverage level; and sending control information to the user terminal by using a sending resource corresponding to the first coverage level, so as to instruct the user terminal to set the coverage level of the user terminal to the first coverage level according to the corresponding information, where content included in the control information includes information indicating an identity of the user terminal. 
     In a first possible implementation manner of the second aspect, the sending control information to the user terminal by using a sending resource corresponding to the first coverage level includes: periodically sending the control information to the user terminal by using the sending resource corresponding to the first coverage level. 
     With reference to the second aspect, or the first possible implementation manner of the second aspect, in a second possible implementation manner, the determining a coverage level of the user terminal as a first coverage level includes: detecting quality of data transmission between a communications device and the user terminal; and determining the coverage level of the user terminal as the first coverage level according to the quality. 
     According to a third aspect, an embodiment of the present invention provides a method for setting a coverage level of user terminal, including: receiving control information from a communications device; parsing the control information to obtain content included in the control information; and setting, if the content includes information for instructing to set a coverage level of the user terminal to a first coverage level in at least one coverage level, the coverage level of the user terminal to the first coverage level. 
     In a first possible implementation manner of the third aspect, the receiving control information from a communications device includes: receiving, from the communications device, the control information sent by using a dedicated sending resource, where the dedicated sending resource is only used to send information to the user terminal. 
     In a second possible implementation manner of the third aspect, the receiving control information from a communications device includes: receiving, from the communications device, the control information sent by using a designated sending resource, where the designated sending resource is corresponding to one coverage level in the at least one coverage level; and the setting, if the content includes information for instructing to set a coverage level of the user terminal to a first coverage level in at least one coverage level, the coverage level of the user terminal to the first coverage level includes: setting the coverage level of the user terminal to the first coverage level if the content includes information indicating an identity of the user terminal and the information for instructing to set the coverage level of the user terminal to the first coverage level in the at least one coverage level. 
     In a third possible implementation manner of the third aspect, the designated sending resource is corresponding to a highest coverage level in the at least one coverage level. 
     In a fourth possible implementation manner of the third aspect, the receiving control information from a communications device includes: receiving, from the communications device, the control information sent by using a common sending resource, where the common sending resource is corresponding to several coverage levels in the at least one coverage level. 
     With reference to any one of the third aspect, or the first to the fourth possible implementation manners of the third aspect, in a fifth possible implementation manner, before the receiving control information, the method further includes: setting the coverage level of the user terminal to a second coverage level in the at least one coverage level, where the first coverage level is higher than the second coverage level. 
     With reference to any one of the third aspect, or the first to the fifth possible implementation manners of the third aspect, in a sixth possible implementation manner, the receiving control information includes: detecting quality of data transmission between the communications device and the user terminal; and if the quality is lower than a quality threshold, receiving the control information. 
     According to a fourth aspect, an embodiment of the present invention provides a method for indicating a coverage level for a user terminal (UE), including: determining a coverage level of the user terminal as a first coverage level in at least one coverage level; and sending control information to the user terminal, so as to instruct the user terminal to set the coverage level of the user terminal to the first coverage level, where the control information includes information for setting the first coverage level. 
     In a first possible implementation manner of the fourth aspect, the sending control information to the user terminal includes: sending the control information to the user terminal by using a dedicated sending resource, where the dedicated sending resource is only used to send information to the user terminal. 
     In a second possible implementation manner of the fourth aspect, the method further includes: receiving an instruction indicating a designated coverage level, and determining, according to the instruction and a correspondence between the at least one coverage level and at least one sending resource, a sending resource that is corresponding to the designated coverage level and that is in the at least one sending resource; and the sending control information to the user terminal includes: sending the control information to the user terminal by using the sending resource corresponding to the designated coverage level, where the control information further includes information indicating an identity of the user terminal. 
     With reference to the second possible implementation manner of the fourth aspect, in a third possible implementation manner, the designated coverage level is a highest coverage level in the at least one coverage level. 
     In a fourth possible implementation manner of the fourth aspect, the sending control information to the user terminal includes: sending the control information to the user terminal by using a common sending resource, where the common sending resource is corresponding to several coverage levels in the at least one coverage level, and the control information further includes information indicating an identity of the user terminal. 
     With reference to any one of the fourth aspect, or the first to the fourth possible implementation manners of the fourth aspect, in a fifth possible implementation manner, the determining a coverage level of the user terminal as a first coverage level in at least one coverage level includes: detecting quality of data transmission between a communications device and the user terminal; and determining the coverage level of the user terminal as the first coverage level according to the quality. 
     In a sixth possible implementation manner of the fourth aspect, the control information includes downlink control information DCI, and the downlink control information DCI includes information indicating an identity of the user terminal and the information for setting the first coverage level. 
     In a seventh possible implementation manner of the fourth aspect, the sending control information to the user terminal includes: sending the control information to the user terminal by using a Media Access Control MAC control element, where the control information further includes information indicating an identity of the user terminal. 
     In an eighth possible implementation manner of the fourth aspect, the sending control information to the user terminal includes: sending the control information to the user terminal by using an enhanced dedicated channel-absolute grant channel E-AGCH. 
     In a ninth possible implementation manner of the fourth aspect, the sending control information to the user terminal includes: sending the control information to the user terminal by using a data code channel, where the control information exists in a form of data, the data code channel is used to send data, and the control information further includes information indicating an identity of the user terminal. 
     According to a fifth aspect, an embodiment of the present invention provides a method for indicating a coverage level for a user terminal (UE), including: determining a coverage level of the user terminal as a first coverage level in at least one coverage level; determining a time interval according to the first coverage level; receiving, at a first moment, first information sent from the user terminal; determining a second moment according to the first moment and the time interval; and sending information to the user terminal at the second moment, so as to instruct the user terminal to set the coverage level of the user terminal to the first coverage level, where the time interval between the second moment and the first moment is used to indicate the first coverage level. 
     In a first possible implementation manner of the fifth aspect, the time interval is T+N or T−N, where T is a preset delay, and N is an integer multiple of 5120 or 4096 chips. 
     With reference to the fifth aspect, or the first possible implementation manner of the fifth aspect, in a second possible implementation manner, the first information includes a preamble sequence, and the second information includes an acquisition indicator channel for a preamble sequence signature. 
     According to a sixth aspect, an embodiment of the present invention provides a user terminal (UE), including: a corresponding information receiving unit, configured to receive corresponding information from a communications device, where the corresponding information indicates a correspondence between at least one sending resource and at least one coverage level; a control information receiving unit, configured to receive, from the communications device, at least one segment of control information sent by using the at least one sending resource, where each segment of control information in the at least one segment of control information is sent by using one sending resource in the at least one sending resource; a parsing module, configured to parse the at least one segment of control information to obtain content included in the at least one segment of control information; and a setting module, configured to: if content included in one segment of control information in the at least one segment of control information includes information indicating an identity of the user terminal, set, according to the corresponding information, a coverage level of the user terminal to a first coverage level corresponding to a sending resource by using which the one segment of control information is sent. 
     In a first possible implementation manner of the sixth aspect, the setting module is specifically configured to set the coverage level of the user terminal to the first coverage level according to the corresponding information if the content included in the one segment of control information in the at least one segment of control information includes the information indicating the identity of the user terminal and at least one of the following information: uplink/downlink scheduling information, a request for aperiodic channel quality indicator reporting, a change indication and an uplink power control command of a multicast control channel, or an acknowledgment/negative acknowledgment ACK/NACK feedback on random access channel RACH resource allocation and uplink data. 
     With reference to the sixth aspect, or the first possible implementation manner of the sixth aspect, in a second possible implementation manner, the at least one segment of control information includes several segments of control information, the control information receiving unit is specifically configured to periodically receive the several segments of control information, and the parsing module is specifically configured to periodically parse the several segments of control information to obtain content included in the several segments of control information. 
     With reference to any one of the sixth aspect, or the first and the second possible implementation manners of the sixth aspect, in a third possible implementation manner, the setting module is further configured to: before the receiving at least one segment of control information sent by using the at least one sending resource, set the coverage level of the user terminal to a second coverage level in the at least one coverage level. 
     With reference to the third possible implementation manner of the sixth aspect, in a fourth possible implementation manner, the first coverage level is different from the second coverage level. 
     With reference to the fourth possible implementation manner of the sixth aspect, in a fifth possible implementation manner, the first coverage level is one level or several higher than the second coverage level. 
     With reference to any one of the sixth aspect, or the first to the fifth possible implementation manners of the sixth aspect, in a sixth possible implementation manner, the control information receiving unit includes: a quality detection unit, configured to detect quality of data transmission between the communications device and the user terminal; and an information receiving unit, configured to: if the quality is lower than a quality threshold, receive, from the communications device, the at least one segment of control information sent by using the at least one sending resource. 
     With reference to any one of the sixth aspect, or the first to the sixth possible implementation manners of the sixth aspect, in a seventh possible implementation manner, the information indicating the identity of the user terminal includes a user terminal identity existing in cyclic redundancy check code in a form of implicit code. 
     According to a seventh aspect, an embodiment of the present invention provides a communications device, including: a corresponding information sending module, configured to send corresponding information to user terminal, where the corresponding information indicates a correspondence between at least one sending resource and at least one coverage level; a level determining module, configured to determine a coverage level of the user terminal as a first coverage level in the at least one coverage level; and a setting information sending module, configured to send control information to the user terminal by using a sending resource corresponding to the first coverage level, so as to instruct the user terminal to set the coverage level of the user terminal to the first coverage level according to the corresponding information, where content included in the control information includes information indicating an identity of the user terminal. 
     In a first possible implementation manner of the seventh aspect, the setting information sending module is specifically configured to periodically send the control information to the user terminal by using the sending resource corresponding to the first coverage level. 
     With reference to the seventh aspect, or the first possible implementation manner of the seventh aspect, in a second possible implementation manner, the level determining module includes: a quality detection unit, configured to detect quality of data transmission between the communications device and the user terminal; and a level determining uint, configured to determine the coverage level of the user terminal as the first coverage level according to the quality. 
     According to an eighth aspect, an embodiment of the present invention provides a user terminal (UE), including: a control information receiving unit, configured to receive control information from a communications device; a parsing module, configured to parse the control information to obtain content included in the control information; and a setting module, configured to: if the content includes information for instructing to set a coverage level of the user terminal to a first coverage level, set the coverage level of the user terminal to the first coverage level. 
     In a first possible implementation manner of the eighth aspect, the control information receiving unit is specifically configured to receive the control information sent by using a dedicated sending resource, where the dedicated sending resource is only used to send information to the user terminal. 
     In a second possible implementation manner of the eighth aspect, the control information receiving unit is specifically configured to receive, from the communications device, the control information sent by using a designated sending resource, where the designated sending resource is corresponding to one coverage level in the at least one coverage level, and the setting module is specifically configured to: if the content includes information indicating an identity of the user terminal and the information for instructing to set the coverage level of the user terminal to the first coverage level, set the coverage level of the user terminal to the first coverage level. 
     In a third possible implementation manner of the eighth aspect, the control information receiving unit is specifically configured to receive, from the communications device, the control information sent by using a common sending resource, where the common sending resource may be corresponding to several coverage levels in at least one coverage level. 
     With reference to any one of the eighth aspect, or the first to the third possible implementation manners of the eighth aspect, in a fourth possible implementation manner, the setting module is further specifically configured to: before the control information is received, set the coverage level of the user terminal to a second coverage level in the at least one coverage level, where the first coverage level is higher than the second coverage level. 
     With reference to any one of the eighth aspect, or the first to the fourth possible implementation manners of the eighth aspect, in a fifth possible implementation manner, the control information receiving unit includes: a quality detection unit, configured to detect quality of data transmission between the communications device and the user terminal; and an information receiving unit, configured to: if the quality is lower than a quality threshold, receive the control information. 
     According to a ninth aspect, an embodiment of the present invention provides a communications device, including: a level determining module, configured to determine a coverage level of user terminal as a first coverage level in at least one coverage level; and a setting information sending module, configured to send control information to the user terminal, so as to instruct the user terminal to set the coverage level of the user terminal to the first coverage level, where the control information includes information for setting the first coverage level. 
     In a first possible implementation manner of the ninth aspect, the setting information sending module is specifically configured to send the control information to the user terminal by using a dedicated sending resource, where the dedicated sending resource is only used to send information to the user terminal. 
     In a second possible implementation manner of the ninth aspect, the communications device further includes: an instruction receiving module, configured to receive an instruction indicating a designated coverage level; and a correspondence module, configured to determine, according to the instruction and a correspondence between the at least one coverage level and at least one sending resource, a sending resource that is corresponding to the designated coverage level and that is in the at least one sending resource; and the setting information sending module is specifically configured to send the control information to the user terminal by using the sending resource corresponding to the designated coverage level, where the control information further includes information indicating an identity of the user terminal. 
     With reference to the second possible implementation manner of the ninth aspect, in a third possible implementation manner, the designated coverage level is a highest coverage level in the at least one coverage level. 
     With reference to the third possible implementation manner of the ninth aspect, in a fourth possible implementation manner, the setting information sending module is specifically configured to send the control information to the user terminal by using a common sending resource, where the common sending resource is corresponding to several coverage levels in the at least one coverage level, and the control information further includes information indicating an identity of the user terminal. 
     With reference to any one of the ninth aspect, or the first to the fourth possible implementation manners of the ninth aspect, in a fifth possible implementation manner, the level determining module includes: a quality detection unit, configured to detect quality of data transmission between the communications device and the user terminal; and a level determining uint, configured to determine the coverage level of the user terminal as the first coverage level according to the quality. 
     In a sixth possible implementation manner of the ninth aspect, the control information includes downlink control information DCI, and the downlink control information DCI includes information indicating an identity of the user terminal and the information for setting the first coverage level. 
     In a seventh possible implementation manner of the ninth aspect, the setting information sending module is specifically configured to send the control information to the user terminal by using a Media Access Control MAC control element, where the control information further includes information indicating an identity of the user terminal. 
     In an eighth possible implementation manner of the ninth aspect, the setting information sending module is specifically configured to send the control information to the user terminal by using an enhanced dedicated channel-absolute grant channel E-AGCH. 
     In a ninth possible implementation manner of the ninth aspect, the setting information sending module is specifically configured to send the control information to the user terminal by using a data code channel, where the control information exists in a form of data, the data code channel is used to send data, and the control information further includes information indicating an identity of the user terminal. 
     According to a tenth aspect, an embodiment of the present invention provides a communications device, including a level determining module, configured to determine a coverage level of user terminal as a first coverage level in at least one coverage level; an interval determining module, configured to determine a time interval according to the first coverage level; an information receiving unit, configured to receive, at a first moment, first information sent from the user terminal; a moment determining module, configured to determine a second moment according to the first moment and the time interval; and a setting module, configured to send second information to the user terminal at the second moment, so as to instruct the user terminal to set the coverage level of the user terminal to the first coverage level, where the time interval between the second moment and the first moment is used to indicate the first coverage level. 
     In a first possible implementation manner of the tenth aspect, the time interval is T+N or T−N, where T is a preset delay, and N is an integer multiple of 5120 or 4096 chips. 
     With reference to the tenth aspect, or the first possible implementation manner of the tenth aspect, in a second possible implementation manner, the first information includes a preamble sequence, and the second information includes an acquisition indicator channel for a preamble sequence signature. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       To describe the technical solutions in the embodiments of the present invention more clearly, the following briefly describes the accompanying drawings required for describing the embodiments. Apparently, the accompanying drawings in the following description show merely some embodiments of the present invention, and a person of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts. 
         FIG. 1  is a schematic flowchart of a method for setting a coverage level of a user terminal (UE) according to a first embodiment of the present invention; 
         FIG. 2  is a schematic flowchart of a method  200  for indicating a coverage level for a user terminal (UE) according to a second embodiment of the present invention; 
         FIG. 3  is a schematic flowchart of a method for setting a coverage level of a user terminal (UE) according to a third embodiment of the present invention; 
         FIG. 4  is a schematic flowchart of a method for indicating a coverage level for a user terminal (UE) according to a fourth embodiment of the present invention; 
         FIG. 5  is a schematic flowchart of a method for indicating a coverage level for a user terminal (UE) according to a fifth embodiment of the present invention; 
         FIG. 6  is a schematic structural diagram of user terminal according to a sixth embodiment of the present invention; 
         FIG. 7  is a schematic structural diagram of a control information receiving unit in  FIG. 6 ; 
         FIG. 8  is a schematic structural diagram of a communications device according to a seventh embodiment of the present invention; 
         FIG. 9  is a schematic structural diagram of a level determining module in  FIG. 8 ; 
         FIG. 10  is a schematic structural diagram of user terminal according to an eighth embodiment of the present invention; 
         FIG. 11  is a schematic structural diagram of a control information receiving unit in  FIG. 10 ; 
         FIG. 12  is a schematic structural diagram of a communications device according to a ninth embodiment of the present invention; 
         FIG. 13  is a schematic structural diagram of a level determining module in  FIG. 12 ; 
         FIG. 14  is another schematic structural diagram of a communications device according to a ninth embodiment of the present invention; 
         FIG. 15  is a schematic structural diagram of a communications device according to a tenth embodiment of the present invention; 
         FIG. 16  is a schematic structural diagram of user terminal according to an eleventh embodiment of the present invention; 
         FIG. 17  is a schematic structural diagram of a communications device according to a twelfth embodiment of the present invention; 
         FIG. 18  is a schematic structural diagram of user terminal according to a thirteenth embodiment of the present invention; 
         FIG. 19  is a schematic structural diagram of a communications device according to a fourteenth embodiment of the present invention; and 
         FIG. 20  is a schematic structural diagram of a communications device according to a fifteenth embodiment of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The following clearly describes the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are merely some but not all of the embodiments of the present invention. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention. 
     A person of ordinary skill in the art may understand that all or some of the processes of the methods in the embodiments may be implemented by a computer program instructing related hardware. The program may be stored in a computer readable storage medium. When the program runs, the processes of the methods in the embodiments are performed. The foregoing storage medium may be a magnetic disk, an optical disc, a read-only memory (ROM), or a random access memory (RAM). 
       FIG. 1  is a schematic flowchart of a method  100  for setting a coverage level of a user terminal (UE) according to a first embodiment of the present invention. 
     In step S 102 , receive corresponding information from a communications device. The corresponding information indicates a correspondence between at least one sending resource and at least one coverage level. In a case described in this application document, a base station determines a physical-layer parameter and/or a higher-layer parameter according to a coverage level. The physical-layer parameter or the higher-layer parameter or both need to be used when the base station sends a signal, so that the user terminal at the coverage level can reliably receive the signal. In the case described in this application document, poorer reception performance of the user terminal indicates a higher coverage level of the user terminal. 
     In step S 104 , receive, from the communications device, at least one segment of control information sent by using the at least one sending resource. Each segment of control information in the at least one segment of control information is sent by using one sending resource in the at least one sending resource. 
     In step S 106 , parse the at least one segment of control information to obtain content included in the at least one segment of control information. 
     In step S 108 , if content included in one segment of control information in the at least one segment of control information includes information indicating an identity of the user terminal, set, according to the corresponding information, a coverage level of the user terminal to a first coverage level that is in the at least one coverage level and that is corresponding to a sending resource by using which the one segment of control information is sent. The information indicating the identity of the user terminal may include a user terminal identity existing in cyclic redundancy check code in a form of implicit code. 
     Compared with the user terminal, the communications device can more accurately determine the coverage level of the user terminal. The coverage level of the user terminal is set according to an instruction of the communications device, so that the coverage level of the user terminal is more accurately set, and an actual communication requirement is better met. 
     In an embodiment, in step S 108 , the setting, according to the corresponding information if content included in one segment of control information in the at least one segment of control information includes information indicating an identity of the user terminal, a coverage level of the user terminal to a first coverage level that is in the at least one coverage level and that is corresponding to a sending resource by using which the one segment of control information is sent specifically includes: setting the coverage level of the user terminal to the first coverage level according to the corresponding information if the content included in the one segment of control information in the at least one segment of control information includes the information indicating the identity of the user terminal and at least one of the following information: uplink/downlink scheduling information, a request for aperiodic channel quality indicator reporting, a change indication and an uplink power control command of a multicast control channel, or an acknowledgment/negative acknowledgment ACK/NACK feedback on random access channel RACH resource allocation and uplink data. 
     In an embodiment, the at least one segment of control information includes several segments of control information. The receiving at least one segment of control information sent by using the at least one sending resource includes: periodically receiving the several segments of control information. The parsing the at least one segment of control information to obtain content included in the at least one segment of control information includes: periodically parsing the several segments of control information to obtain content included in the several segments of control information. Therefore, in this method, the coverage level of the user terminal may be periodically set. 
     In an embodiment, before the at least one segment of control information sent by using the at least one sending resource is received from the communications device, the coverage level of the user terminal is set to a second coverage level in the at least one coverage level. That is, before receiving the instruction of the communications device, the user terminal may pre-estimate a coverage level and perform setting according to a pre-estimated result. The first coverage level may be different from the second coverage level. For example, the first coverage level is one level or several levels higher than the second coverage level. 
     In an embodiment, that at least one segment of control information sent by using the at least one sending resource is received from the communications device includes: quality of data transmission between the communications device and the user terminal is detected, and if the quality is lower than a quality threshold, the at least one segment of control information sent by using the at least one sending resource is received from the communications device. That is, the user terminal may be subject to the setting to the coverage level by the communications device only when communication quality is lower than expected. 
       FIG. 2  is a schematic flowchart of a method  200  for indicating a coverage level for a user terminal (UE) according to a second embodiment of the present invention. 
     In step S 202 , send corresponding information to the user terminal. The corresponding information indicates a correspondence between at least one sending resource and at least one coverage level. 
     In step S 204 , determine a coverage level of the user terminal as a first coverage level in the at least one coverage level. 
     In step S 206 , send control information to the user terminal by using a sending resource corresponding to the first coverage level, so as to instruct the user terminal to set the coverage level of the user terminal to the first coverage level according to the corresponding information. Content included in the control information includes information indicating an identity of the user terminal. The information indicating the identity of the user terminal may include a user terminal identity existing in cyclic redundancy check code in a form of implicit code. 
     Compared with the user terminal, a communications device can more accurately determine the coverage level of the user terminal. The coverage level of the user terminal is set according to an instruction of the communications device, so that the coverage level of the user terminal is more accurately set, and an actual communication requirement is better met. 
     In an embodiment, that the sending control information to the user terminal by using a sending resource corresponding to the first coverage level includes: the control information is periodically sent to the user terminal by using the sending resource corresponding to the first coverage level. Therefore, in this method, the coverage level of the user terminal may be periodically set. 
     In an embodiment, that the determining a coverage level of the user terminal as a first coverage level includes: detecting quality of data transmission between the communications device and the user terminal, and determining the coverage level of the user terminal as the first coverage level according to the quality. That is, the communications device sets the coverage level of the user terminal only when communication quality is lower than expected. 
       FIG. 3  is a schematic flowchart of a method  300  for setting a coverage level of a user terminal (UE) according to a third embodiment of the present invention. 
     In step S 302 , receive control information from a communications device. 
     In step S 304 , parse the control information to obtain content included in the control information. 
     In step S 306 , if the content included in the control information includes information for instructing to set a coverage level of the user terminal to a first coverage level in at least one coverage level, set the coverage level of the user terminal to the first coverage level. 
     Compared with the user terminal, the communications device can more accurately determine the coverage level of the user terminal. The coverage level of the user terminal is set according to an instruction of the communications device, so that the coverage level of the user terminal is more accurately set, and an actual communication requirement is better met. 
     In an embodiment, that the receiving control information from a communications device includes: the control information sent by using a dedicated sending resource is received from the communications device. The dedicated sending resource is only used to send information to the user terminal. That is, the control information does not need to include information indicating an identity of the user terminal, and the coverage level of the user terminal can still be set. 
     In an embodiment, that the receiving control information from a communications device includes: the control information sent by using a designated sending resource is received from the communications device. that the setting the coverage level of the user terminal to the first coverage level if the content included in the control information includes information for instructing to set a coverage level of the user terminal to a first coverage level in at least one coverage level includes: if the content included in the control information includes information indicating an identity of the user terminal and the information for instructing to set the coverage level of the user terminal to the first coverage level in the at least one coverage level, setting the coverage level of the user terminal to the first coverage level. The designated sending resource may be corresponding to one coverage level in the at least one coverage level. For example, the designated sending resource is corresponding to a highest coverage level in the at least one coverage level. In another embodiment, that control information is received from a communications device includes: the control information sent by using a common sending resource is received from the communications device. The common sending resource may be corresponding to several coverage levels in the at least one coverage level. 
     In an embodiment, the method  300  further includes: before the receiving the control information, setting the coverage level of the user terminal to a second coverage level in the at least one coverage level. That is, before receiving the instruction of the communications device, the user terminal may pre-estimate a coverage level and perform setting according to a pre-estimated result. The first coverage level may be higher than the second coverage level. For example, the first coverage level is one level or several levels higher than the second coverage level. 
     In an embodiment, the receiving control information includes: quality of data transmission between the communications device and the user terminal is detected, and if the quality is lower than a quality threshold, the control information is received. That is, the user terminal may be subject to the setting to the coverage level by the communications device only when communication quality is lower than expected. 
       FIG. 4  is a schematic flowchart of a method  400  for indicating a coverage level for a user terminal (UE) according to a fourth embodiment of the present invention. 
     In step S 402 , determine a coverage level of the user terminal as a first coverage level in at least one coverage level. that the determining a coverage level of the user terminal as a first coverage level in at least one coverage level may specifically include: detecting quality of data transmission between a communications device and the user terminal, and determining the coverage level of the user terminal as the first coverage level according to the quality. 
     In step S 404 , send control information to the user terminal, so as to instruct the user terminal to set the coverage level of the user terminal to the first coverage level. The control information includes information for setting the first coverage level. 
     Compared with the user terminal, the communications device can more accurately determine the coverage level of the user terminal. The coverage level of the user terminal is set according to an instruction of the communications device, so that the coverage level of the user terminal is more accurately set, and an actual communication requirement is better met. 
     In an embodiment, that the sending control information to the user terminal includes: sending the control information to the user terminal by using a dedicated sending resource. The dedicated sending resource is only used to send information to the user terminal. That is, in this embodiment, the control information does not need to include information indicating an identity of the user terminal, and the coverage level of the user terminal can still be set. 
     In an embodiment, the method  400  further includes: receiving an instruction indicating a designated coverage level, and determining a sending resource that is corresponding to the designated coverage level and that is in at least one sending resource according to the instruction and a correspondence between the at least one coverage level and the at least one sending resource. that the sending control information to the user terminal includes: sending the control information to the user terminal by using the sending resource corresponding to the designated coverage level. The designated coverage level may be a highest coverage level in the at least one coverage level. The control information further includes information indicating an identity of the user terminal. 
     In another embodiment, the sending control information to the user terminal includes: sending the control information to the user terminal by using a common sending resource. The common sending resource is corresponding to several coverage levels in the at least one coverage level. The control information further includes information indicating an identity of the user terminal. 
     In an embodiment, the control information includes downlink control information DCI, and the downlink control information DCI includes information indicating an identity of the user terminal and the information for setting the first coverage level. 
     In an embodiment, that the sending control information to the user terminal includes: sending the control information to the user terminal by using a Media Access Control MAC control element. The control information further includes information indicating an identity of the user terminal. 
     In another embodiment, the sending control information to the user terminal includes: sending the control information to the user terminal by using an enhanced dedicated channel-absolute grant channel E-AGCH. 
     In still another embodiment, the sending control information to the user terminal includes: sending the control information to the user terminal by using a data code channel. The control information further includes information indicating an identity of the user terminal. The control information exists in a form of data. The data code channel is used to send data. 
       FIG. 5  is a schematic flowchart of a method  500  for indicating a coverage level for a user terminal (UE) according to a fifth embodiment of the present invention. 
     In step S 502 , determine a coverage level of the user terminal as a first coverage level in at least one coverage level. 
     In step S 504 , determine a time interval according to the first coverage level. The time interval may be T+N or T−N, where T is a preset delay, and N is an integer multiple of 5120 or 4096 chips. 
     In step S 506 , receive first information sent from the user terminal at a first moment. 
     In step S 508 , determine a second moment according to the first moment and the time interval. 
     In step S 510 , send second information to the user terminal at the second moment, so as to instruct the user terminal to set the coverage level of the user terminal to the first coverage level. The time interval between the second moment and the first moment is used to indicate the first coverage level. 
     In an embodiment, the first information includes a preamble sequence, and the second information includes an acquisition indicator channel for a preamble sequence signature. 
     That is, the coverage level of the user terminal may be set according to the time interval. 
       FIG. 6  is a schematic structural diagram of user terminal  600  according to a sixth embodiment of the present invention. The user terminal  600  includes a corresponding information receiving unit  602 , a control information receiving unit  604 , a parsing module  606 , and a setting module  608 . The corresponding information receiving unit  602  is configured to receive corresponding information from a communications device, where the corresponding information indicates a correspondence between at least one sending resource and at least one coverage level. The control information receiving unit  604  is configured to receive, from the communications device, at least one segment of control information sent by using the at least one sending resource, where each segment of control information in the at least one segment of control information is sent by using one sending resource in the at least one sending resource. In an embodiment, the control information receiving unit  604  includes a quality detection unit  702  and an information receiving unit  704  that are shown in  FIG. 7 . The quality detection unit  702  is configured to detect quality of data transmission between the communications device and the user terminal. The information receiving unit  704  is configured to: if the quality is lower than a quality threshold, receive, from the communications device, the at least one segment of control information sent by using the at least one sending resource. The parsing module  606  is configured to parse the at least one segment of control information to obtain content included in the at least one segment of control information. The setting module  608  is configured to: if content included in one segment of control information in the at least one segment of control information includes information indicating an identity of the user terminal, set, according to the corresponding information, a coverage level of the user terminal to a first coverage level corresponding to a sending resource by using which the one segment of control information is sent. The information indicating the identity of the user terminal may include a user terminal identity existing in cyclic redundancy check code in a form of implicit code. 
     In an embodiment, the setting module  608  is specifically configured to set the coverage level of the user terminal to the first coverage level according to the corresponding information if the content included in the one segment of control information in the at least one segment of control information includes the information indicating the identity of the user terminal and at least one of the following information: uplink/downlink scheduling information, a request for aperiodic channel quality indicator reporting, a change indication and an uplink power control command of a multicast control channel, or an acknowledgment/negative acknowledgment ACK/NACK feedback on random access channel RACH resource allocation and uplink data. 
     In an embodiment, the at least one segment of control information includes several segments of control information, the control information receiving unit  604  is specifically configured to periodically receive the several segments of control information, and the parsing module  606  is specifically configured to periodically parse the several segments of control information to obtain content included in the several segments of control information. 
     In an embodiment, the setting module  608  is further configured to: before the at least one segment of control information sent by using the at least one sending resource is received, set the coverage level of the user terminal to a second coverage level in the at least one coverage level. The first coverage level may be different from the second coverage level. For example, the first coverage level may be one level or several levels higher than the second coverage level. 
       FIG. 8  is a schematic structural diagram of a communications device  800  according to a seventh embodiment of the present invention. The communications device  800  includes a corresponding information sending module  802 , a level determining module  804 , and a setting information sending module  806 . The corresponding information sending module  802  is configured to send corresponding information to user terminal, where the corresponding information indicates a correspondence between at least one sending resource and at least one coverage level. In an embodiment, the setting information sending module  806  is specifically configured to periodically send a control information to the user terminal by using a sending resource corresponding to a first coverage level. The level determining module  804  is configured to determine a coverage level of the user terminal as the first coverage level in the at least one coverage level. The level determining module  804  may specifically include a quality detection unit  902  and a level determining uint  904  that are shown in  FIG. 9 . The quality detection unit  902  is configured to detect quality of data transmission between the communications device and the user terminal. The level determining uint  904  is configured to determine the coverage level of the user terminal as the first coverage level according to the quality. The setting information sending module  806  is configured to send the control information to the user terminal by using the sending resource corresponding to the first coverage level, so as to instruct the user terminal to set the coverage level of the user terminal to the first coverage level according to the corresponding information. Content included in the control information includes information indicating an identity of the user terminal. 
       FIG. 10  is a schematic structural diagram of user terminal  1000  according to an eighth embodiment of the present invention. The user terminal  1000  includes a control information receiving unit  1002 , a parsing module  1004 , and a setting module  1006 . The control information receiving unit  1002  is configured to receive control information from a communications device. In an embodiment, the control information receiving unit  1002  includes a quality detection unit  1102  and an information receiving unit  1104  that are shown in  FIG. 11 . The quality detection unit  1102  is configured to detect quality of data transmission between the communications device and the user terminal. The information receiving unit  1104  is configured to: if the quality is lower than a quality threshold, receive the control information. The parsing module  1004  is configured to parse the control information to obtain content included in the control information. The setting module  1006  is configured to: if the content included in the control information includes information for instructing to set a coverage level of the user terminal to a first coverage level, set the coverage level of the user terminal to the first coverage level. In an embodiment, the setting module  1006  is further specifically configured to: before the control information is received, set the coverage level of the user terminal to a second coverage level in at least one coverage level, where the first coverage level is higher than the second coverage level. 
     In an embodiment, the control information receiving unit  1002  is specifically configured to receive the control information sent by using a dedicated sending resource. The dedicated sending resource is only used to send information to the user terminal. 
     In another embodiment, the control information receiving unit  1002  is specifically configured to receive, from the communications device, the control information sent by using a designated sending resource, where the designated sending resource is corresponding to one coverage level in the at least one coverage level, and the setting module  1006  is specifically configured to set the coverage level of the user terminal to the first coverage level if the content included in the control information includes information indicating an identity of the user terminal and the information for instructing to set the coverage level of the user terminal to the first coverage level. 
     In still another embodiment, the control information receiving unit  1002  is specifically configured to receive, from the communications device, the control information sent by using a common sending resource. The common sending resource may be corresponding to several coverage levels in at least one coverage level. 
       FIG. 12  is a schematic structural diagram of a communications device  1200  according to a ninth embodiment of the present invention. The communications device  1200  includes a level determining module  1202  and a setting information sending module  1204 . The level determining module  1202  is configured to determine a coverage level of user terminal as a first coverage level in at least one coverage level. In an embodiment, the level determining module  1202  includes a quality detection unit  1302  and a level determining uint  1304  that are shown in  FIG. 13 . The quality detection unit  1302  is configured to detect quality of data transmission between the communications device and the user terminal. The level determining uint  1304  is configured to determine the coverage level of the user terminal as the first coverage level according to the quality. The setting information sending module  1204  is configured to send control information to the user terminal, so as to instruct the user terminal to set the coverage level of the user terminal to the first coverage level, where the control information includes information for setting the first coverage level. 
     In an embodiment, the setting information sending module  1204  is specifically configured to send the control information to the user terminal by using a dedicated sending resource. The dedicated sending resource is only used to send information to the user terminal. 
     In another embodiment, the communications device  1200  further includes an instruction receiving module  1402  and a correspondence module  1404  that are shown in  FIG. 14 . The instruction receiving module  1402  is configured to receive an instruction indicating a designated coverage level. The correspondence module  1404  is configured to determine, according to the instruction and a correspondence between the at least one coverage level and at least one sending resource, a sending resource that is corresponding to the designated coverage level and that is in the at least one sending resource. The setting information sending module  1204  is specifically configured to send the control information to the user terminal by using the sending resource corresponding to the designated coverage level. The control information further includes information indicating an identity of the user terminal. The designated coverage level may be a highest coverage level in the at least one coverage level. 
     In still another embodiment, the setting information sending module  1204  is specifically configured to send the control information to the user terminal by using a common sending resource. The common sending resource is corresponding to several coverage levels in the at least one coverage level. The control information further includes information indicating an identity of the user terminal. 
     In an embodiment, the control information includes downlink control information DCI, and the downlink control information DCI includes information indicating an identity of the user terminal and the information for setting the first coverage level. 
     In another embodiment, the setting information sending module  1204  is specifically configured to send the control information to the user terminal by using a Media Access Control MAC control element. The control information further includes information indicating an identity of the user terminal. 
     In still another embodiment, the setting information sending module  1204  is specifically configured to send the control information to the user terminal by using an enhanced dedicated channel-absolute grant channel E-AGCH. 
     In yet another embodiment, the setting information sending module  1204  is specifically configured to send the control information to the user terminal by using a data code channel. The control information exists in a form of data. The data code channel is used to send data. The control information further includes information indicating an identity of the user terminal. 
       FIG. 15  is a schematic structural diagram of a communications device  1500  according to a tenth embodiment of the present invention. The communications device  1500  includes a level determining module  1502 , an interval determining module  1504 , an information receiving unit  1506 , a moment determining module  1508 , and a setting module  1510 . The level determining module  1502  is configured to determine a coverage level of user terminal as a first coverage level in at least one coverage level. The interval determining module  1504  is configured to determine a time interval according to the first coverage level. The information receiving unit  1506  is configured to receive, at a first moment, first information sent from the user terminal. The moment determining module  1508  is configured to determine a second moment according to the first moment and the time interval. The setting module  1510  is configured to send second information to the user terminal at the second moment, so as to instruct the user terminal to set the coverage level of the user terminal to the first coverage level. The time interval between the second moment and the first moment is used to indicate the first coverage level. The first information may include a preamble sequence. The second information may include an acquisition indicator channel for a preamble sequence signature. In an embodiment, the time interval is T+N or T−N, where T is a preset delay, and N is an integer multiple of 5120 or 4096 chips. 
       FIG. 16  is a schematic structural diagram of user terminal  1600  according to an eleventh embodiment of the present invention. The user terminal  1600  includes a transceiver  1602 , a central processing unit (CPU)  1604 , and a memory  1606 . 
     The transceiver  1602  is configured to: receive corresponding information from a communications device, where the corresponding information indicates a correspondence between at least one sending resource and at least one coverage level; and receive, from the communications device, at least one segment of control information sent by using the at least one sending resource, where each segment of control information in the at least one segment of control information is sent by using one sending resource in the at least one sending resource. In an embodiment, the transceiver  1602  is configured to: detect quality of data transmission between the communications device and the user terminal, and if the quality is lower than a quality threshold, receive, from the communications device, the at least one segment of control information sent by using the at least one sending resource. 
     The memory  1606  is configured to store an instruction. The CPU  1604  is configured to: read the instruction from the memory  1606 , parse the at least one segment of control information according to the instruction to obtain content included in the at least one segment of control information, and if content included in one segment of control information in the at least one segment of control information includes information indicating an identity of the user terminal, set, according to the corresponding information, a coverage level of the user terminal to a first coverage level corresponding to a sending resource by using which the one segment of control information is sent. The information indicating the identity of the user terminal may include a user terminal identity existing in cyclic redundancy check code in a form of implicit code. In an embodiment, the at least one segment of control information includes several segments of control information, the transceiver  1602  is specifically configured to periodically receive the several segments of control information, and the CPU  1604  is specifically configured to periodically parse the several segments of control information according to the instruction read from the memory  1606  to obtain content included in the several segments of control information. 
     In an embodiment, the CPU  1604  is further configured to: before the at least one segment of control information sent by using the at least one sending resource is received, set the coverage level of the user terminal to a second coverage level in the at least one coverage level according to the instruction read from the memory  1606 . The first coverage level may be different from the second coverage level. For example, the first coverage level may be one level or several levels higher than the second coverage level. 
       FIG. 17  is a schematic structural diagram of a communications device  1700  according to a twelfth embodiment of the present invention. The communications device  1700  includes a transceiver  1702 , a CPU  1704 , and a memory  1706 . 
     The transceiver  1702  is configured to send corresponding information to user terminal, where the corresponding information indicates a correspondence between at least one sending resource and at least one coverage level. In an embodiment, the transceiver  1702  is specifically configured to periodically send a control information to the user terminal by using a sending resource corresponding to a first coverage level. 
     The memory  1706  is configured to store an instruction. The CPU  1704  is configured to: read the instruction from the memory  1706 , and determine a coverage level of the user terminal as the first coverage level in the at least one coverage level according to the instruction. In an embodiment, the CPU  1704  is further configured to detect quality of data transmission between the communications device and the user terminal according to the instruction read from the memory  1706 , and determine the coverage level of the user terminal as the first coverage level according to the quality. The transceiver  1702  is further configured to send the control information to the user terminal by using the sending resource corresponding to the first coverage level, so as to instruct the user terminal to set the coverage level of the user terminal to the first coverage level according to the corresponding information. Content included in the control information includes information indicating an identity of the user terminal. 
       FIG. 18  is a schematic structural diagram of user terminal  1800  according to a thirteenth embodiment of the present invention. The user terminal  1800  includes a transceiver  1802 , a central processing unit (CPU)  1804 , and a memory  1806 . 
     The transceiver  1802  is configured to receive control information from a communications device. In an embodiment, the transceiver  1802  is configured to detect quality of data transmission between the communications device and the user terminal, and receive the control information if the quality is lower than a quality threshold. The memory  1806  is configured to store an instruction. The CPU  1804  is configured to: read the instruction from the memory  1806 , and parse the control information according to the instruction to obtain content included in the control information. The CPU  1804  is configured to: if the content included in the control information includes information for instructing to set a coverage level of the user terminal to a first coverage level, set the coverage level of the user terminal to the first coverage level. In an embodiment, the CPU  1804  is further specifically configured to: before the control information is received, set the coverage level of the user terminal to a second coverage level in at least one coverage level. The first coverage level is higher than the second coverage level. 
     In an embodiment, the transceiver  1802  is specifically configured to receive the control information sent by using a dedicated sending resource. The dedicated sending resource is only used to send information to the user terminal. 
     In another embodiment, the transceiver  1802  is specifically configured to receive, from the communications device, the control information sent by using a designated sending resource, where the designated sending resource is corresponding to one coverage level in the at least one coverage level, and the CPU  1804  is specifically configured to: if the content included in the control information includes information indicating an identity of the user terminal and the information for instructing to set the coverage level of the user terminal to the first coverage level, set the coverage level of the user terminal to the first coverage level. 
     In still another embodiment, the transceiver  1802  is specifically configured to receive, from the communications device, the control information sent by using a common sending resource. The common sending resource may be corresponding to several coverage levels in at least one coverage level. 
       FIG. 19  is a schematic structural diagram of a communications device  1900  according to a fourteenth embodiment of the present invention. The communications device  1900  includes a transceiver  1902 , a CPU  1904 , and a memory  1906 . 
     The memory  1906  is configured to store an instruction. The CPU  1904  is configured to: read the instruction from the memory  1906 , and determine a coverage level of user terminal as a first coverage level in at least one coverage level according to the instruction. In an embodiment, the CPU  1904  is configured to detect quality of data transmission between the communications device and the user terminal according to the instruction, and determine the coverage level of the user terminal as the first coverage level according to the quality. The transceiver  1902  is configured to send control information to the user terminal, so as to instruct the user terminal to set the coverage level of the user terminal to the first coverage level. The control information includes information for setting the first coverage level. 
     In an embodiment, the transceiver  1902  is specifically configured to send the control information to the user terminal by using a dedicated sending resource. The dedicated sending resource is only used to send information to the user terminal. 
     In another embodiment, the transceiver  1902  is further configured to receive an instruction indicating a designated coverage level. The CPU  1904  is configured to determine, according to a correspondence between the at least one coverage level and at least one sending resource and the instruction indicating the designated coverage level, a sending resource that is corresponding to the designated coverage level and that is in the at least one sending resource. The transceiver  1902  is specifically configured to send the control information to the user terminal by using the sending resource corresponding to the designated coverage level. The control information further includes information indicating an identity of the user terminal. The designated coverage level may be a highest coverage level in the at least one coverage level. 
     In still another embodiment, the transceiver  1902  is specifically configured to send the control information to the user terminal by using a common sending resource. The common sending resource is corresponding to several coverage levels in the at least one coverage level. The control information further includes information indicating an identity of the user terminal. 
     In an embodiment, the control information includes downlink control information DCI, and the downlink control information DCI includes information indicating an identity of the user terminal and the information for setting the first coverage level. 
     In another embodiment, the transceiver  1902  is specifically configured to send the control information to the user terminal by using a Media Access Control MAC control element. The control information further includes information indicating an identity of the user terminal. 
     In still another embodiment, the transceiver  1902  is specifically configured to send the control information to the user terminal by using an enhanced dedicated channel-absolute grant channel E-AGCH. 
     In yet another embodiment, the transceiver  1902  is specifically configured to send the control information to the user terminal by using a data code channel. The control information exists in a form of data. The data code channel is used to send data. The control information further includes information indicating an identity of the user terminal. 
       FIG. 20  is a schematic structural diagram of a communications device  2000  according to a fifteenth embodiment of the present invention. The communications device  2000  includes a transceiver  2002 , a CPU  2004 , and a memory  2006 . 
     The memory  2006  is configured to store an instruction. The CPU  2004  is configured to: read the instruction from the memory  2006 , determine a coverage level of user terminal as a first coverage level in at least one coverage level according to the instruction, and determine a time interval according to the first coverage level. The transceiver  2002  is configured to receive, at a first moment, first information sent from the user terminal. The CPU  2004  is configured to: determine a second moment according to the first moment and the time interval, and send second information to the user terminal at the second moment, so as to instruct the user terminal to set the coverage level of the user terminal to the first coverage level. The time interval between the second moment and the first moment is used to indicate the first coverage level. The first information may include a preamble sequence. The second information may include an acquisition indicator channel for a preamble sequence signature. In an embodiment, the time interval is T+N or T−N, where T is a preset delay, and N is an integer multiple of 5120 or 4096 chips. 
     In this application document, each apparatus embodiment and a corresponding method embodiment thereof have similar advantages. 
     What is disclosed above is merely examples of embodiments of the present invention, and certainly is not intended to limit the protection scope of the present invention. Therefore, equivalent variations made in accordance with the claims of the present invention shall fall within the scope of the present invention.