Patent Publication Number: US-10764806-B2

Title: Method and apparatus for assisting terminal in measuring

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 14/880,993, filed on Oct. 12, 2015, which is a continuation of International Patent Application No. PCT/CN2013/074178, filed on Apr. 12, 2013. All of the afore-mentioned patent applications are hereby incorporated by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     Embodiments of the present invention relate to the field of communications network technologies, and in particular, to a method and an apparatus for assisting a terminal in measuring. 
     BACKGROUND 
     In a cellular system, to expand a capacity and a coverage scope of a hotspot area, a concept of a heterogeneous network is introduced. In the heterogeneous network, a macro base station is responsible for coverage of a wide scope, and a low power node (LPN) or a micro base station is adopted to cover a hotspot area. The micro base station has a small coverage scope, and users often change, thereby causing that a state in which UE is not served for a relatively long time. In this case, the micro base station is usually disabled, that is, most energy-consuming elements of the micro base station are disabled, so that power can be reduced and interference to a neighboring cell can be reduced. 
     In the prior art, the micro base station is in a sleep state after being disabled, periodic sending of a discovery pilot (Discovery Reference Signal, DRS) signal is usually adopted, so that when a user approaches the coverage scope of the micro base station, the DRS signal can be detected by user equipment (UE), and the UE determines signal strength of the micro base station by using the DRS signal. 
     However, because the DRS signal is a sparse synchronization signal in a time domain, and a time period is in seconds or longer, two situations occur: The first one is that a signal of a neighboring micro base station is not strong enough, but a location at which the DRS signal is located is at a crest of a fast fading channel, so that the UE incorrectly determines that the signal of the micro base station can serve the UE itself; the second one is that the signal of the neighboring micro base station is strong enough, but the location at which the DRS signal is located is at a trough of the channel, so that the UE considers that the signal of the micro base station is not strong enough to serve the UE itself. 
     SUMMARY 
     Embodiments of the present invention provide a method and an apparatus for assisting a terminal in measuring, which may implement correct measurement on signal strength of a micro base station, thereby preventing UE from incorrectly determining the signal strength of the micro base station. 
     According to a first aspect, the present invention provides a method for assisting a terminal in measuring, including: 
     receiving, by a first base station, a measurement result for a second base station sent by user equipment UE, where the first base station provides a service for the UE; 
     determining, by the first base station according to the measurement result, whether a handover operation needs to be started; and 
     instructing, by the first base station when the handover operation needs to be started, the second base station to start up, and handing over the UE to the second base station for a service provided by the second base station. 
     According to a second aspect, the present invention provides a method for assisting a terminal in measuring, including: 
     receiving, by user equipment UE after detecting a discovery pilot DRS signal sent by a second base station, a radio resource management pilot RRM-RS signal sent by the second base station; 
     performing, by the UE, measurement on the second base station according to the RRM-RS signal to obtain a measurement result; and 
     sending, by the UE, the measurement result to a first base station, so that the first base station instructs, according to the measurement result, the second base station to start up, and hands over the UE to the second base station. 
     According to a third aspect, the present invention provides a method for assisting a terminal in measuring, including: 
     periodically sending, by a second base station, a discovery pilot DRS signal; and 
     sending, by the second base station, a radio resource management pilot RRM-RS signal, so that user equipment UE performs measurement on the second base station according to the RRM-RS signal after detecting the DRS signal. 
     According to a fourth aspect, the present invention provides an apparatus for assisting a terminal in measuring, located in a first base station and including: 
     a receiving module, configured to receive a measurement result for a second base station sent by user equipment UE, where the first base station provides a service for the UE; and provide the measurement result for a determining module; 
     the determining module, configured to determine, according to the measurement result received by the receiving module, whether a handover operation needs to be started, and provide a result of the determining for a processing module; and 
     the processing module, configured to: instruct, according to the result determined by the determining module that the handover operation needs to be started, the second base station to start up, and hand over the UE to the second base station for a service provided by the second base station. 
     According to a fifth aspect, the present invention provides an apparatus for assisting a terminal in measuring, including: 
     a detection module, configured to detect a discovery pilot DRS signal sent by a second base station; 
     a receiving module, configured to: after the detection module detects the DRS signal, receive a radio resource management pilot RRM-RS signal sent by the second base station, and provide the RRM-RS signal for a measurement module; 
     the measurement module, configured to perform, according to the RRM-RS signal received by the receiving module, measurement on the second base station to obtain a measurement result, and provide the measurement result for a sending module; and 
     the sending module, configured to send the measurement result obtained by the measurement module to a first base station, so that the first base station instructs, according to the measurement result, the second base station to start up, and hands over the UE to the second base station. 
     According to a sixth aspect, the present invention provides an apparatus for assisting a terminal in measuring, located in a second base station and including: 
     a first sending module, configured to periodically send a discovery pilot DRS signal; and 
     a second sending module, configured to send a radio resource management pilot RRM-RS signal, so that user equipment UE performs measurement on the second base station according to the RRM-RS signal after detecting the DRS signal. 
     According to a seventh aspect, the present invention provides an apparatus for assisting a terminal in measuring, located in a first base station and including: 
     a memory, configured to store information including a program routine; 
     a receiver, configured to receive a measurement result for a second base station sent by user equipment UE, where the first base station provides a service for the UE; and provide the measurement result for a processor; and 
     the processor, connected to the memory and the receiver, configured to control execution of the program routine, and specifically configured to determine, according to the measurement result received by the receiver, whether a handover operation needs to be started; when the handover operation needs to be started, instruct the second base station to start up, and hand over the UE to the second base station for a service provided by the second base station. 
     According to an eighth aspect, the present invention provides an apparatus for assisting a terminal in measuring, including: 
     a memory, configured to store information including a program routine; 
     a receiver, configured to receive a discovery pilot DRS signal sent by a second base station, receive a radio resource management pilot RRM-RS signal, and provide the RRM-RS signal for a processor; 
     the processor, connected to the memory, the receiver, and a transmitter, configured to control execution of the program routine, and specifically configured to perform, according to the RRM-RS signal received by the receiver, measurement on the second base station to obtain a measurement result, and provide the measurement result for the transmitter; and 
     transmitter, configured to send the measurement result obtained by the processor to a first base station, so that the first base station instructs, according to the measurement result, the second base station to start up, and hands over the UE to the second base station. 
     According to a ninth aspect, the present invention provides an apparatus for assisting a terminal in measuring, located in a second base station and including: 
     a receiver, a transmitter, a memory, and a processor that is separately connected to the receiver, the transmitter, and the memory, where: 
     the memory is configured to store information including a program routine; and 
     transmitter is configured to periodically send a discovery pilot DRS signal, and send a radio resource management pilot RRM-RS signal, so that user equipment UE performs measurement on the second base station according to the RRM-RS signal after detecting the DRS signal. 
     In the method and the apparatus for assisting a terminal in measuring according to the embodiments of the present invention, a first base station receives a measurement result for a second base station sent by UE, where the first base station provides a service for the UE; the first base station determines, according to the measurement result, whether a handover operation needs to be started; when the handover operation needs to be started, the first base station instructs the second base station to start up, and hands over the UE to the second base station for a service provided by the second base station. Compared with a problem in the prior art that because a DRS signal is a sparse synchronization signal in a time domain, and a time period is in seconds or longer, the UE performs erroneous determining on a signal of the second base station, in the embodiments of the present invention, correct measurement on signal strength of a micro base station may be implemented, thereby preventing the UE from incorrectly determining the signal strength of the micro base station. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       To describe the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces 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 flowchart of a method for assisting a terminal in measuring according to an embodiment of the present invention; 
         FIG. 2  is a flowchart of another method for assisting a terminal in measuring according to an embodiment of the present invention; 
         FIG. 3  is a flowchart of another method for assisting a terminal in measuring according to an embodiment of the present invention; 
         FIG. 4( a )  is a schematic diagram of a period of sending a discovery pilot DRS signal and a pilot RS signal by a second base station according to an embodiment of the present invention; 
         FIG. 4( b )  is another schematic diagram of a period of sending a discovery pilot DRS signal and a pilot RS signal by a second base station according to an embodiment of the present invention; 
         FIG. 5  is a flowchart of another method for assisting a terminal in measuring according to an embodiment of the present invention; 
         FIG. 6  is a flowchart of another method for assisting a terminal in measuring according to an embodiment of the present invention; 
         FIG. 7  is a flowchart of another method for assisting a terminal in measuring according to an embodiment of the present invention; 
         FIG. 8  is a flowchart of another method for assisting a terminal in measuring according to an embodiment of the present invention; 
         FIG. 9  is a block diagram of an apparatus for assisting a terminal in measuring according to an embodiment of the present invention; 
         FIG. 10  is a block diagram of another apparatus for assisting a terminal in measuring according to an embodiment of the present invention; 
         FIG. 11  is a block diagram of another apparatus for assisting a terminal in measuring according to an embodiment of the present invention; 
         FIG. 12  is a block diagram of another apparatus for assisting a terminal in measuring according to an embodiment of the present invention; 
         FIG. 13  is a block diagram of another apparatus for assisting a terminal in measuring according to an embodiment of the present invention; 
         FIG. 14  is a block diagram of another apparatus for assisting a terminal in measuring according to an embodiment of the present invention; 
         FIG. 15  is a block diagram of another apparatus for assisting a terminal in measuring according to an embodiment of the present invention; 
         FIG. 16  is a block diagram of another apparatus for assisting a terminal in measuring according to an embodiment of the present invention; and 
         FIG. 17  is a block diagram of another apparatus for assisting a terminal in measuring according to an 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. 
     As shown in  FIG. 1 , an embodiment of the present invention provides a method for assisting a terminal in measuring, the method is executed by a first base station, and the first base station may be specifically a macro base station. The method includes the following steps: 
     Step  101 : The first base station receives a measurement result for a second base station and sent by UE, where the first base station provides a service for the UE. 
     In this embodiment, the first base station may be a macro base station, and the second base station may be a micro base station. The macro base station has a strong signal, a wide coverage scope, heavy traffic to bear, and a large floor area; the micro base station has low power, a small floor area, a small signal coverage scope, easy planning, and a capability of increasing a hotspot capacity. 
     The measurement result of the second base station includes reference signal received power (RSRP) and reference signal received quality (RSRQ). 
     Step  102 : The first base station determines, according to the measurement result, whether a handover operation needs to be started. 
     The first base station may analyze the measurement result by using a handover decision algorithm to determine whether the first base station needs to start the handover operation. For example, when a value of the RSRP in the measurement result is greater than or equal to a threshold CH 1 , and when a value of the RSRQ is greater than or equal to a threshold CH 2 , the first base station determines to start the handover operation. On the contrary, when the value of the RSRP in the measurement result is less than the threshold CH 1 , and/or when the value of the RSRQ is less than the threshold CH 2 , the first base station determines not to start the handover operation. 
     Step  103 : When the handover operation needs to be started, the first base station instructs the second base station to start up, and hands over the UE to the second base station for a service provided by the second base station. 
     When the first base station determines, by using the handover decision algorithm, that the measurement result corresponding to the second base station meets a requirement, the first base station needs to start the handover operation and send a wake-up instruction to the second base station, where the wake-up instruction is used to instruct the second base station to start up. After the second base station receives the wake-up instruction sent by the first base station, the second base station starts up, that is, the second base station is in an activated state, and the first base station hands over the UE to the second base station. 
     When the first base station uses an intra-frequency handover or an inter-frequency handover, the first base station sends a handover preparation request to the second base station. After the second base station receives the handover preparation request, the first base station sends configuration information to the second base station, where the configuration information includes specific configuration information of the UE and radio resource control (RRC) protocol context information of the UE. Then, the first base station sends an RRC connection reconfiguration message to the UE, where the RRC connection reconfiguration message is used to instruct the UE to perform the handover, and the RRC connection reconfiguration message includes mobility control information and radio resource configuration information. After receiving the RRC connection reconfiguration information, the UE initiates a random access process to access the second base station. 
     When the first base station determines, by using the handover decision algorithm, that the measurement result corresponding to the second base station does not meet the requirement, the first base station does not need to start the handover operation, and therefore does not send the wake-up instruction to the second base station. It may be understood that in this embodiment, the first base station continues to provide a service for the UE. 
     In the method for assisting a terminal in measuring according to this embodiment of the present invention, a first base station receives a measurement result for a second base station and sent by UE, where the first base station provides a service for the UE; the first base station determines, according to the measurement result, whether a handover operation needs to be started; when the handover operation needs to be started, the first base station instructs the second base station to start up, and hands over the UE to the second base station for a service provided by the second base station. Compared with a problem in the prior art that after the UE sends an uplink signal, the second base station starts up according to the uplink signal, but a situation in which the UE does not enter a coverage scope of the second base station may occur, which causes a waste of resources, in this embodiment of the present invention, accurate determining may be implemented on a signal of the second base station to determine whether the second base station needs to start up to provide a service for the UE, thereby reducing an unnecessary resource waste of the second base station. 
     As shown in  FIG. 2 , an embodiment of the present invention provides another method for assisting a terminal in measuring, and the method is executed by UE. The method includes the following steps: 
     Step  201 : After detecting a DRS signal sent by a second base station, the UE receives a radio resource management pilot (Radio Resource Management Reference Signal, RRM-RS) signal sent by the second base station. 
     The UE may be a cell phone (or referred to as a mobile phone), a portable, pocket-sized, handheld, computer-built-in, or in-vehicle mobile apparatus, or the like. The second base station may be a micro base station. The second base station has features such as low power, a small floor area, a small signal coverage scope, easy planning, and a capability of increasing a hotspot capacity. However, because the signal coverage scope is small, a change rate of the UE is relatively high, and a situation in which the UE is not served for a period of time may occur within the coverage scope of the second base station. In this case, the second base station may be disabled, which may be considered that the second base station enters a sleep state. In the sleep state, the second base station may reduce power and reduce interference to a neighboring cell. It should be noted that the second base station periodically sends a DRS signal in the sleep state. The DRS signal is a sparse synchronization signal in a time domain, and a time period is in seconds or longer. The DRS signal includes identity (ID) information of a cell formed by the second base station, frequency channel number information of the second base station, and frequency domain information, time domain information, and sequence information of an RRM-RS signal. The ID information of the cell formed by the second base station includes a cell ID and/or a cell virtual ID. The DRS signal may be an existing synchronization signal, such as a primary synchronization signal (PSS) or a secondary synchronization signal (SSS); or the DRS signal may be a new discovery pilot (New Discovery Reference Signal, NDRS) signal that is newly defined by the second base station. 
     Specifically, the UE receives the RRM-RS signal according to content in the DRS signal. The RRM-RS signal may be a common pilot (Common Reference Signal, CRS) signal, or the RRM-RS signal may be a channel state information pilot (Channel State Information Reference Signal, CSI-RS) signal. 
     Optionally, before the second base station sends the RRM-RS signal, when the UE can receive the DRS signal, it indicates that the UE has entered the coverage scope of the second base station, or the UE is already at an edge of the coverage scope of the second base station. After receiving the DRS signal, the UE sends an uplink signal to the second base station on a carrier corresponding to the second base station, where the uplink signal is used to trigger the second base station to send the RRM-RS signal. After receiving the uplink signal, the second base station starts to send the RRM-RS signal. It should be noted that the uplink signal may be an uplink random access (Random Access Channel, RACH) signal, or the uplink signal may be an uplink sounding pilot (Sounding Reference Signal, SRS) signal. The RRM-RS signal includes channel information of the second base station, which is used to determine whether a signal of the second base station may serve the UE. The RRM-RS signal is a CRS signal, or the RRM-RS signal is a CSI-RS signal. 
     Step  202 : The UE performs measurement on the second base station according to the RRM-RS signal to obtain a measurement result. 
     Optionally, the UE starts to receive the RRM-RS signal after waiting for a first predetermined time, and performs the measurement on the second base station to obtain the measurement result. It should be noted that the first predetermined time may be a time set by a timer on the UE; or 
     optionally, after receiving a first control instruction sent by a first base station, the UE starts to receive the RRM-RS signal according to the first control instruction, and performs the measurement on the second base station to obtain the measurement result, where the first control instruction is used to instruct the UE to perform the measurement on the second base station; or 
     optionally, after receiving a second control instruction sent by the second base station, the UE starts to receive the RRM-RS signal according to the second control instruction, and performs the measurement on the second base station to obtain the measurement result, where the second control instruction is used to instruct the UE to perform the measurement on the second base station. 
     When the RRM-RS signal is a CRS signal, the UE performs RRM measurement on the second base station according to the CRS signal to obtain a first measurement result, where the first measurement result includes RSRP and RSRQ; or when the RRM-RS signal is a CSI-RS signal, the UE performs RRM measurement on the second base station according to the CSI-RS signal to obtain a second measurement result, where the second measurement result includes CSI-RSRP. 
     Step  203 : The UE sends the measurement result to a first base station, so that the first base station instructs, according to the measurement result, the second base station to start up, and hands over the UE to the second base station. 
     Specifically, the UE sends the RSRP and the RSRQ, or the CSI-RSRP to the first base station. 
     In the method for assisting a terminal in measuring according to this embodiment of the present invention, user equipment UE detects a discovery pilot DRS signal sent by a second base station; the UE receives a radio resource management pilot RRM-RS signal sent by the second base station; the UE performs measurement on the second base station according to the RRM-RS signal to obtain a measurement result; the UE sends the measurement result to a first base station, so that the first base station instructs, according to the measurement result, the second base station to start up, and hands over the UE to the second base station. Compared with a problem in the prior art that because a DRS signal is a sparse synchronization signal in a time domain, and a time period is in seconds or longer, the UE performs erroneous determining on a signal of the second base station, in this embodiment of the present invention, correct measurement on signal strength of a micro base station may be implemented, thereby preventing the UE from incorrectly determining the signal strength of the micro base station. 
     As shown in  FIG. 3 , an embodiment of the present invention provides another method for assisting a terminal in measuring, the method is executed by a second base station, and the second base station may specifically be a micro base station. The method includes the following steps: 
     Step  301 : The second base station periodically sends a DRS signal. 
     As a micro base station, the second base station has features such as low power, a small floor area, a small signal coverage scope, easy planning, and a capability of increasing a hotspot capacity. However, because the signal coverage scope is small, a change rate of UE within the coverage scope is relatively high, and a situation in which the UE is not served for a period of time may occur within the coverage scope of the second base station. In this case, the second base station may be disabled, which may be considered that the second base station enters a sleep state, so as to reduce power and reduce interference to a neighboring cell. It should be noted that when the second base station is in the sleep state, the second base station may still periodically send a DRS signal. The DRS signal is a sparse synchronization signal in a time domain, and a time period is in seconds or longer. The DRS signal includes ID information of a cell formed by the second base station, frequency channel number information of the second base station, and frequency domain information, time domain information, and sequence information of an RRM-RS signal. The ID information of the cell formed by the second base station includes a cell ID and/or a cell virtual ID. The second base station may reuse an existing synchronization signal, such as a PSS signal or an SSS signal; or the second base station may newly define a synchronization signal: an NDRS signal, and in this case, a sending period of the NDRS signal may be greater than or equal to a sending period of the existing synchronization signal. For example, the sending period of the existing synchronization signal may be 5 ms. 
     Step  302 : The second base station sends an RRM-RS signal, so that UE performs measurement on the second base station according to the RRM-RS signal after detecting the DRS signal. 
     Optionally, the second base station starts to send the RRM-RS signal according to a received uplink signal sent by the UE, where the uplink signal may be a RACH signal, or the uplink signal may be an SRS signal. The uplink signal is used to trigger the second base station to send the RRM-RS signal. After the second base station receives the uplink signal sent by the UE, it may be considered that the second base station enters a semi-sleep state. In the semi-sleep state, the second base station starts to send the RRM-RS signal, where the RRM-RS signal may be a CRS signal, or the RRM-RS signal may be a CSI-RS signal, so that the UE performs the measurement on the second base station according to a different type of the RRM-RS signal. 
     Optionally, the second base station starts to send the RRM-RS signal according to a trigger instruction sent by a first base station, where the trigger instruction is used to trigger the second base station to send the RRM-RS signal. It may be understood that in this embodiment, the first base station is a macro base station, and in this case, is a base station that provides a service for the UE. Certainly, a type of the first base station is not limited in this embodiment. 
     Optionally, the second base station can send the RRM-RS signal without a need to receive the uplink signal sent by the UE or the trigger instruction sent by the first base station. Specifically, when the second base station is in the sleep state, after sending a DRS signal, the second base station sends the RRM-RS signal for a third predetermined time, and then continues to send a DRS signal in such a cycle, where the third predetermined time is a time within a period of sending the DRS signal except a time of sending the DRS signal or a predetermined time within a period of sending the DRS signal. For example, a period of sending the DRS signal by the second base station is used as an example for description. As shown in  FIG. 4( a ) , the period of sending the DRS signal by the second base station is 1 s. After sending a DRS signal, the second base station starts to send an RRM-RS signal, and then continues to send a DRS signal; the second base station sends signals in this cycle. Alternatively, as shown in  FIG. 4( b ) , the period of sending the DRS signal by the second base station is 1 s. After sending a DRS signal, the second base station sends an RRM-RS signal of 200 ms, and then the second base station enters a cycle of a next period to continue to send a DRS signal. It should be noted that for the RRM-RS signal of 200 ms sent between the two DRS signals, a start time of sending the RRM-RS signal by the second base station is not limited in this embodiment. For ease of description, in  FIG. 4( b ) , the RRM-RS signal starts to be sent in 400 ms after the DRS signal is sent, that is, there is an interval of 400 ms between the RRM-RS signal and the two DRS signals. 
     In the method for assisting a terminal in measuring according to this embodiment of the present invention, a second base station periodically sends a discovery pilot DRS signal; the second base station sends a radio resource management pilot RRM-RS signal, so that user equipment UE receives the RRM-RS signal and performs measurement on the second base station according to the RRM-RS signal. Compared with a problem in the prior art that the second base station sends only the DRS signal, causing that UE incorrectly determines signal strength of the second base station, or the second base station sends both the DRS signal and the RRM-RS signal, causing a waste of resources, in this embodiment of the present invention, correct measurement on signal strength of a micro base station may be implemented, thereby preventing the UE from incorrectly determining the signal strength of the micro base station and achieving objectives of reducing power and reducing interference to a neighboring cell. 
     As shown in  FIG. 5 , an embodiment of the present invention provides another method for assisting a terminal in measuring, and the method includes the following steps: 
     Step  501 : A second base station periodically sends a DRS signal. 
     In this embodiment, the second base station may be a micro base station. A situation in which UE is not served for a period of time may occur within a coverage scope of the second base station. In this case, the second base station may be disabled, which may be considered that the second base station enters a sleep state. In the sleep state, the second base station may reduce power and reduce interference to a neighboring cell. It should be noted that the second base station periodically sends a DRS signal in the sleep state. The DRS signal is a sparse synchronization signal in a time domain, and a time period is in seconds or longer. The DRS signal may reduce power of the second base station and reduce interference to a neighboring cell of the second base station. The DRS signal includes ID information of a cell formed by the second base station, frequency channel number information of the second base station, and frequency domain information, time domain information, and sequence information of an RRM-RS signal. The ID information of the cell formed by the second base station includes a cell ID and/or a cell virtual ID. The second base station may reuse an existing synchronization signal, such as a PSS signal or an SSS signal; or the second base station may newly define a synchronization signal: an NDRS signal, and in this case, a sending period of the NDRS signal may be greater than or equal to a sending period of the existing synchronization signal. For example, the sending period of the existing synchronization signal may be 5 ms. 
     Step  502 : After detecting the DRS signal, UE sends an uplink signal to the second base station. 
     When the UE can detect the DRS signal, it indicates that the UE has entered the coverage scope of the second base station, or the UE is already at an edge of the coverage scope of the second base station. After receiving the DRS signal, the UE sends the uplink signal to the second base station on a carrier corresponding to the second base station, where the uplink signal is used to trigger the second base station to send the RRM-RS signal. It should be noted that the uplink signal may be a RACH signal, or the uplink signal may be an SRS signal. 
     Step  503 : The second base station receives the uplink signal sent by the UE and then starts to send an RRM-RS signal. 
     The RRM-RS signal may be a CRS signal, or the RRM-RS signal may be a CSI-RS signal. It should be noted that after the second base station receives the uplink signal, it may be considered that the second base station enters a semi-sleep state, that is, the second base station sends the RRM-RS signal in the semi-sleep state. 
     Step  504 : The first base station sends a first control instruction to the UE. 
     In this embodiment, the first base station may be a macro base station. The macro base station has features such as a strong signal, a wide coverage scope, heavy traffic to bear, and a large floor area. 
     After the second base station sends the RRM-RS signal, the second base station interacts with the first base station by using an X2 interface or a base station controller (BSC), to notify the first base station that the RRM-RS signal has been sent. Then, the first base station generates the first control instruction and sends the first control instruction to the UE, where the first control instruction is used to instruct the UE to receive the RRM-RS signal. It may be understood that a manner of interaction between the first base station and the second base station is not limited in this embodiment. For ease of description, in this embodiment, a manner in which the interaction between the first base station and the second base station is performed by using an X2 interface or a BSC is used. 
     Step  505 : The second base station sends a second control instruction to the UE. 
     After sending the RRM-RS signal, the second base station generates the second control instruction and then sends the second control instruction to the UE, where the second control instruction is used to instruct the UE to receive the RRM-RS signal. 
     It should be noted that either step  504  or step  505  is performed, and the two steps cannot be performed at the same time, or neither of the two steps may be performed at the same time. In  FIG. 5 , step  504  is indicated by a dashed line arrow, and step  505  is indicated by a dashed line arrow, where a dashed line arrow indicates that this step is an optional step. Certainly, an optional relationship may also be indicated in another manner, and a manner that indicates the optional relationship is not limited in this embodiment of the present invention. 
     Step  506 : The UE receives the RRM-RS signal. 
     After the second base station sends the RRM-RS signal, optionally, the UE may directly receive the RRM-RS signal after detecting the DRS signal sent by the second base station; or the UE needs to wait a first predetermined time set by a timer on the UE and then starts to receive the RRM-RS signal after detecting the DRS signal sent by the second base station. For example, the first predetermined time may be in a unit of millisecond. For example, the first predetermined time may be 20 ms, or the first predetermined time may be 50 ms. Certainly, the time set by the timer on the UE is not limited in this embodiment. Alternatively, the UE starts to receive the RRM-RS signal after receiving the first control instruction sent by the first base station; or the UE starts to receive the RRM-RS signal after receiving the second control instruction sent by the second base station. 
     Step  507 : The UE performs measurement on the second base station according to the RRM-RS signal to obtain a measurement result. 
     When the RRM-RS signal is a CRS signal, the UE performs RRM measurement on the second base station according to the CRS signal to obtain a first measurement result, where the first measurement result includes RSRP and RSRQ; or when the RRM-RS signal is a CSI-RS signal, the UE performs RRM measurement on the second base station according to the CSI-RS signal to obtain a second RRM measurement result, where the second measurement result includes CSI-RSRP. 
     Step  508 : The UE sends the measurement result to the first base station. 
     Specifically, the UE sends the RSRP and the RSRQ, or the CSI-RSRP to the first base station. 
     Step  509 : The first base station determines, according to the measurement result, whether to start a handover operation. 
     The first base station may analyze the measurement result by using a handover decision algorithm to determine whether the first base station needs to start the handover operation. When a value of the RSRP in the first measurement result is greater than or equal to a threshold CH 1 , and when a value of the RSRQ is greater than or equal to a threshold CH 2 , the first base station determines to start the handover operation. On the contrary, when the value of the RSRP in the first measurement result is less than the threshold CH 1 , and/or when the value of the RSRQ is less than the threshold CH 2 , the first base station determines not to start the handover operation. Alternatively, when a value of the CSI-RSRP in the second measurement result is greater than or equal to a threshold CH 1 , the first base station determines to start the handover operation. On the contrary, when the value of the CSI-RSRP in the second measurement result is less than the threshold CH 1 , the first base station determines not to start the handover operation. 
     Step  510 : When the first base station determines to start the handover operation, the first base station starts the handover operation and sends a wake-up instruction to the second base station. 
     When the first base station determines, by using the handover decision algorithm, that the first measurement result or the second measurement result corresponding to the second base station meets a requirement, in this case the first base station needs to start the handover operation and send the wake-up instruction to the second base station, where the wake-up instruction is used to instruct the second base station to start up. After the first base station sends the wake-up instruction to the second base station, step  512  continues to be performed. 
     Step  511 : When determining not to start the handover operation, the first base station does not send the wake-up instruction to the second base station. 
     When the first base station determines, by using the handover decision algorithm, that the first measurement result or the second measurement result corresponding to the second base station does not meet the requirement, in this case the first base station does not need to start the handover operation and does not send the wake-up instruction to the second base station. It may be understood that in this embodiment, the first base station continues to provide a service for the UE. After the first base station determines not to start the handover operation, step  513  continues to be performed. 
     It should be noted that either step  510  or step  511  is performed, and the two steps cannot be performed at the same time. In  FIG. 5 , step  511  is indicated by a dashed box, or step  510  may be indicated by a dashed box, where a dashed box indicates that this step is an optional step. Certainly, an optional relationship may also be indicated in another manner, and a manner that indicates the optional relationship is not limited in this embodiment of the present invention. 
     Step  512 : The second base station starts up after receiving the wake-up instruction; then, a handover is performed between the second base station and the first base station, and the UE is handed over to the second base station. 
     When the second base station starts up according to the wake-up instruction, it may be considered that the second base station enters an activated state. 
     When an intra-frequency handover or an inter-frequency handover is performed between the first base station and the second base station, the first base station sends a handover preparation request to the second base station. After the second base station receives the handover preparation request, the first base station sends configuration information to the second base station, where the configuration information includes specific configuration information of the UE and RRC context information of the UE. Then, the first base station sends an RRC connection reconfiguration message to the UE, where the RRC connection reconfiguration message is used to instruct the UE to perform the handover, and the RRC connection reconfiguration message includes mobility control information and radio resource configuration information. After receiving the RRC connection reconfiguration information, the UE initiates a random access process to access the second base station. 
     After the UE is handed over to a service scope of the second base station, step  514  continues to be performed. 
     Step  513 : When the second base station does not receive the wake-up instruction within a second predetermined time, stop sending the RRM-RS signal. 
     In this embodiment, an entity for setting the second predetermined time is not limited. For example, the second predetermined time may be a time set by the second base station, or the second predetermined time may be a time set by the first base station. For example, when not starting the handover operation, the first base station may send a stop instruction to the second base station, where the stop instruction includes the second predetermined time. The second predetermined time may be in a unit of millisecond. For example, the second predetermined time may be 200 ms. In this embodiment, a range of the second predetermined time is not limited. After waiting the second predetermined time, when the second base station still does not receive the wake-up instruction sent by the first base station, the second base station enters the sleep state again, that is, the second base station sends only the DRS signal and stops sending the RRM-RS signal. 
     Step  514 : When the UE moves out of a coverage scope of the second base station, and there is no other UE within the scope, the second base station enters a sleep state again. 
     When the UE moves out of the coverage scope of the second base station, a handover operation is performed between the second base station and a base station corresponding to a scope to be entered by the UE. When the UE enters a coverage scope of the first base station, a handover operation is directly performed between the second base station and the first base station; or when the UE enters a coverage scope of another micro base station, the second base station, the UE, and the micro base station continue to perform a procedure of step  501  to step  513 . 
     When the UE moves out of the coverage scope of the second base station, and there is no other UE that needs to be served within the scope, the second base station enters the sleep state again. 
     In the method for assisting a terminal in measuring according to this embodiment of the present invention, correct measurement on signal strength of a micro base station may be implemented, thereby preventing UE from incorrectly determining the signal strength of the micro base station and achieving objectives of reducing power and reducing interference to a neighboring cell. 
     As shown in  FIG. 6 , an embodiment of the present invention provides another method for assisting a terminal in measuring, and the method includes the following steps: 
     Step  601 : A second base station periodically sends a DRS signal. 
     In this embodiment, the second base station may be a micro base station. A situation in which UE is not served for a period of time may occur within a coverage scope of the second base station. In this case, the second base station may be disabled, which may be considered that the second base station enters a sleep state. In the sleep state, the second base station may reduce power and reduce interference to a neighboring cell. It should be noted that the second base station periodically sends a DRS signal in the sleep state. The DRS signal includes ID information of a cell formed by the second base station, frequency channel number information of the second base station, and frequency domain information, time domain information, and sequence information of an RRM-RS signal. The ID information of the cell formed by the second base station includes a cell ID and/or a cell virtual ID. The second base station may reuse an existing synchronization signal, such as a PSS signal or an SSS signal; or the second base station may newly define a synchronization signal: an NDRS signal, and in this case, a sending period of the NDRS signal may be greater than or equal to a sending period of the existing synchronization signal. For example, the sending period of the existing synchronization signal may be 5 ms. 
     Step  602 : After receiving the DRS signal, the UE obtains first information of the second base station by parsing the DRS signal. 
     The first information is used to instruct the first base station to trigger the second base station to send the RRM-RS signal. The UE may obtain the ID information of the cell formed by the second base station and the frequency channel number information of the second base station by parsing the DRS signal, that is, the first information includes the ID information formed by the second base station and the frequency channel number information of the second base station, where the ID information of the cell formed by the second base station includes the cell ID and/or the cell virtual ID. 
     Step  603 : The UE sends the first information to a first base station. 
     The UE sends the first information to the first base station by using an air interface. In this embodiment, the first base station is a macro base station. The macro base station has features such as a strong signal, a wide coverage scope, heavy traffic to bear, and a large floor area. 
     Step  604 : The first base station sends a trigger instruction to the second base station according to the first information. 
     The first base station sends the trigger instruction to the second base station by using an X2 interface or a BSC, where the trigger instruction is used to trigger the second base station to send the RRM-RS signal. It may be understood that a manner of interaction between the first base station and the second base station is not limited in this embodiment. For ease of description, in this embodiment, a manner in which the interaction between the first base station and the second base station is performed by using an X2 interface or a BSC is used. 
     Step  605 : The second base station receives the trigger instruction and then starts to send an RRM-RS signal. 
     The RRM-RS signal may be a CRS signal, or the RRM-RS signal may be a CSI-RS signal. It should be noted that after the second base station receives the trigger instruction, it may be considered that the second base station enters a semi-sleep state, that is, the second base station sends the RRM-RS signal in the semi-sleep state. 
     Step  606 : The first base station sends a first control instruction to the UE. 
     After the second base station sends the RRM-RS signal, the second base station interacts with the first base station by using an X2 interface or a BSC, to notify the first base station that the RRM-RS signal has been sent. Then, the first base station generates the first control instruction and sends the first control instruction to the UE, where the first control instruction is used to instruct the UE to receive the RRM-RS signal. It may be understood that a manner of interaction between the first base station and the second base station is not limited in this embodiment. For ease of description, in this embodiment, a manner in which the interaction between the first base station and the second base station is performed by using an X2 interface is used. 
     Step  607 : The second base station sends a second control instruction to the UE. 
     After sending the RRM-RS signal, the second base station generates the second control instruction and then sends the second control instruction to the UE, where the second control instruction is used to instruct the UE to receive the RRM-RS signal. 
     It should be noted that either step  606  or step  607  is performed, and the two steps cannot be performed at the same time, or neither of the two steps may be performed at the same time. In  FIG. 6 , step  606  is indicated by a dashed line arrow, and step  607  is indicated by a dashed line arrow, where a dashed line arrow indicates that this step is an optional step. Certainly, an optional relationship may also be indicated in another manner, and a manner that indicates the optional relationship is not limited in this embodiment of the present invention. 
     Step  608 : The UE receives the RRM-RS signal. 
     After the second base station sends the RRM-RS signal, optionally, the UE may directly receive the RRM-RS signal after detecting the DRS signal sent by the second base station; or the UE needs to wait a first predetermined time set by a timer on the UE and then starts to receive the RRM-RS signal after detecting the DRS signal sent by the second base station. The first predetermined time may be in a unit of millisecond. For example, the first predetermined time may be 20 ms. Certainly, the first predetermined time set by the timer on the UE is not limited in this embodiment. Alternatively, the UE starts to receive the RRM-RS signal after receiving the first control instruction sent by the first base station; or the UE starts to receive the RRM-RS signal after receiving the second control instruction sent by the second base station. 
     Step  609 : The UE performs measurement on the second base station according to the RRM-RS signal to obtain a measurement result. 
     When the RRM-RS signal is a CRS signal, the UE performs RRM measurement on the second base station according to the CRS signal to obtain a first measurement result, where the first measurement result includes RSRP and RSRQ; or when the RRM-RS signal is a CSI-RS signal, the UE performs RRM measurement on the second base station according to the CSI-RS signal to obtain a second measurement result, where the second measurement result includes CSI-RSRP. 
     Step  610 : The UE sends the measurement result to the first base station. 
     Specifically, the UE sends the RSRP and the RSRQ, or the CSI-RSRP to the first base station. 
     Step  611 : The first base station determines, according to the measurement result, whether to start a handover operation. 
     The first base station may analyze the first measurement result or the second measurement result by using a handover decision algorithm to determine whether the first base station needs to start the handover operation. For a process of using the handover decision algorithm by the first base station, refer to detailed description of step  509  in  FIG. 5 , and details are not described herein again. 
     Step  612 : When the first base station determines to start the handover operation, the first base station starts the handover operation and sends a wake-up instruction to the second base station. 
     When the first base station determines, by using the handover decision algorithm, that the first measurement result or the second measurement result corresponding to the second base station meets a requirement, in this case the first base station needs to start the handover operation and send the wake-up instruction to the second base station, where the wake-up instruction is used to instruct the second base station to start up. After the first base station sends the wake-up instruction to the second base station, step  614  continues to be performed. 
     Step  613 : When determining not to start the handover operation, the first base station does not send the wake-up instruction to the second base station. 
     When the first base station determines, by using the handover decision algorithm, that the first measurement result or the second measurement result corresponding to the second base station does not meet the requirement, in this case the first base station does not need to start the handover operation and does not send the wake-up instruction to the second base station. It may be understood that in this embodiment, the first base station continues to provide a service for the UE. After the first base station determines not to start the handover operation, step  615  continues to be performed. 
     It should be noted that either step  612  or step  613  is performed, and the two steps cannot be performed at the same time. In  FIG. 6 , step  613  is indicated by a dashed box, or step  612  may be indicated by a dashed box, where a dashed box indicates that this step is an optional step. Certainly, an optional relationship may also be indicated in another manner, and a manner that indicates the optional relationship is not limited in this embodiment of the present invention. 
     Step  614 : The second base station starts up after receiving the wake-up instruction; then, a handover is performed between the second base station and the first base station, and the UE is handed over to the second base station. 
     When the second base station starts up according to the wake-up instruction, it may be considered that the second base station enters an activated state. 
     For an operation process in which an intra-frequency handover or an inter-frequency handover is performed between the first base station and the second base station, refer to detailed description of step  512  in  FIG. 5 , and details are not described herein again. 
     After the UE is handed over to a service scope of the second base station, step  616  continues to be performed. 
     Step  615 : When the second base station does not receive the wake-up instruction within a second predetermined time, stop sending the RRM-RS signal. 
     In this embodiment, an entity for setting the second predetermined time is not limited. For example, the second predetermined time may be a time set by the second base station, or the second predetermined time may be a time set by the first base station. For example, when not starting the handover operation, the first base station may send a stop instruction to the second base station, where the stop instruction includes the second predetermined time. In this embodiment, a range of the second predetermined time is not limited. After waiting the second predetermined time, when the second base station still does not receive the wake-up instruction sent by the first base station, the second base station enters the sleep state again, that is, the second base station sends only the DRS signal and stops sending the RRM-RS signal. 
     Step  616 : When the UE moves out of a coverage scope of the second base station, and there is no other UE within the scope, the second base station enters a sleep state again. 
     When the UE moves out of the coverage scope of the second base station, a handover operation is performed between the second base station and a base station corresponding to a scope to be entered by the UE. When the UE enters a coverage scope of the first base station, a handover operation is directly performed between the second base station and the first base station; or when the UE enters a coverage scope of another micro base station, the second base station, the UE, and the micro base station continue to perform a procedure of step  601  to step  615 . 
     In the method for assisting a terminal in measuring according to this embodiment of the present invention, correct measurement on signal strength of a micro base station may be implemented, thereby preventing UE from incorrectly determining the signal strength of the micro base station and achieving objectives of reducing power and reducing interference to a neighboring cell. 
     As shown in  FIG. 7 , an embodiment of the present invention provides another method for assisting a terminal in measuring, and the method includes the following steps: 
     Step  701 : A second base station periodically sends a DRS signal. 
     In this embodiment, the second base station may be a micro base station. A situation in which UE is not served for a period of time may occur within a coverage scope of the second base station. In this case, the second base station may be disabled, which may be considered that the second base station enters a sleep state. In the sleep state, the second base station periodically sends a DRS signal. The DRS signal includes ID information of a cell formed by the second base station, frequency channel number information of the second base station, and frequency domain information, time domain information, and sequence information of an RRM-RS signal. The ID information of the cell formed by the second base station includes a cell ID and/or a cell virtual ID. The second base station may reuse an existing synchronization signal, such as a PSS signal or an SSS signal; or the second base station may newly define a synchronization signal: an NDRS signal, and in this case, a sending period of the NDRS signal may be greater than or equal to a sending period of the existing synchronization signal. For example, the sending period of the existing synchronization signal may be 5 ms. 
     Step  702 : After detecting the DRS signal, UE sends an uplink signal to the second base station. 
     When the UE can receive the DRS signal, it indicates that the UE has entered the coverage scope of the second base station, or the UE is already at an edge of the coverage scope of the second base station. After receiving the DRS signal, the UE sends the uplink signal to the second base station on a carrier corresponding to the second base station, where the uplink signal is used to trigger the second base station to send the RRM-RS signal. It should be noted that the uplink signal may be a RACH signal, or the uplink signal may be an SRS signal. 
     It should be noted that after the UE sends the uplink signal to the second base station, step  705  continues to be performed. 
     Step  703 : After detecting the DRS signal, the UE obtains first information of the second base station by parsing the DRS signal and then sends the first information to a first base station. 
     In this embodiment, the first base station is a macro base station. The UE sends the first information to the first base station by using an air interface, and the first information is used to instruct the first base station to trigger the second base station to send the RRM-RS signal. The UE may obtain the ID information of the second base station and the frequency channel number information of the second base station by parsing the DRS signal, that is, the first information includes the ID information of the second base station and the frequency channel number information of the second base station. It may be understood that the UE sends the first information to the first base station by using an air interface. 
     It should be noted that either step  702  or step  703  is performed, and the two steps cannot be performed at the same time. In  FIG. 7 , step  703  and step  704  are indicated by dashed boxes, or step  702  may be indicated by a dashed box, where a dashed box indicates that this step is an optional step. Certainly, an optional relationship may also be indicated in another manner, and a manner that indicates the optional relationship is not limited in this embodiment of the present invention. 
     After the UE sends the first information to the first base station, step  704  continues to be performed. 
     Step  704 : The first base station receives the first information and sends a trigger instruction to the second base station according to the first information. 
     The first base station sends the trigger instruction to the second base station by using an X2 interface or a BSC, where the trigger instruction is used to trigger the second base station to send the RRM-RS signal. It may be understood that a manner of interaction between the first base station and the second base station is not limited in this embodiment. For ease of description, in this embodiment, a manner in which the interaction between the first base station and the second base station is performed by using an X2 interface or a BSC is used. 
     Step  705 : After receiving the uplink signal sent by the UE or receiving the trigger instruction sent by the first base station, the second base station starts to send an RRM-RS signal. 
     The RRM-RS signal may be a CRS signal, or the RRM-RS signal may be a CSI-RS signal. It should be noted that after the second receives the uplink signal sent by the UE or after the second base station receives the trigger instruction sent by the first base station, it may be considered that the second base station enters a semi-sleep state, that is, the second base station sends the RRM-RS signal in the semi-sleep state. 
     Step  706 : The first base station sends a first control instruction to the UE. 
     After the second base station sends the RRM-RS signal, the second base station interacts with the first base station by using an X2 interface or a BSC, to notify the first base station that the RRM-RS signal has been sent. Then, the first base station generates the first control instruction and sends the first control instruction to the UE, where the first control instruction is used to instruct the UE to receive the RRM-RS signal. It may be understood that a manner of interaction between the first base station and the second base station is not limited in this embodiment. For ease of description, in this embodiment, a manner in which the interaction between the first base station and the second base station is performed by using an X2 interface is used. 
     Step  707 : The second base station sends a second control instruction to the UE. 
     After sending the RRM-RS signal, the second base station generates the second control instruction and then sends the second control instruction to the UE, where the second control instruction is used to instruct the UE to receive the RRM-RS signal. 
     It should be noted that either step  706  or step  707  is performed, and the two steps cannot be performed at the same time, or neither of the two steps may be performed at the same time. In  FIG. 7 , step  706  is indicated by a dashed line arrow, and step  707  is indicated by a dashed line arrow, where a dashed line arrow indicates that this step is an optional step. Certainly, an optional relationship may also be indicated in another manner, and a manner that indicates the optional relationship is not limited in this embodiment of the present invention. 
     Step  708 : The UE receives the RRM-RS signal. 
     After the second base station sends the RRM-RS signal, optionally, the UE may directly receive the RRM-RS signal; or the UE needs to wait a first predetermined time set by a timer on the UE and then starts to receive the RRM-RS signal. The first predetermined time may be in a unit of millisecond. For example, a unit of the first predetermined time may be 50 ms. Certainly, the first predetermined time set by the timer on the UE is not limited in this embodiment. Alternatively, the UE starts to receive the RRM-RS signal after receiving the first control instruction sent by the first base station; or the UE starts to receive the RRM-RS signal after receiving the second control instruction sent by the second base station. 
     Step  709 : The UE performs measurement on the second base station according to the RRM-RS signal to obtain a measurement result. 
     When the RRM-RS signal is a CRS signal, the UE performs RRM measurement on the second base station according to the CRS signal to obtain a first measurement result, where the first measurement result includes RSRP and RSRQ; or when the RRM-RS signal is a CSI-RS signal, the UE performs RRM measurement on the second base station according to the CSI-RS signal to obtain a second measurement result, where the second measurement result includes CSI-RSRP. 
     Step  710 : The UE sends the measurement result to the first base station. 
     Specifically, the UE sends the RSRP and the RSRQ, or the CSI-RSRP to the first base station. 
     Step  711 : The first base station determines, according to the measurement result, whether to start up the second base station. 
     The first base station may analyze the first measurement result or the second measurement result by using a handover decision algorithm to determine whether the first base station needs to start a handover operation. For a process of using the handover decision algorithm by the first base station, refer to detailed description of step  509  in  FIG. 5 , and details are not described herein again. 
     Step  712 : When determining to start up the second base station, the first base station sends a wake-up instruction to the second base station and sends an activation instruction to the UE. 
     When the first base station determines, by using the handover decision algorithm, that the first measurement result or the second measurement result corresponding to the second base station meets a requirement, in this case the first base station sends the wake-up instruction to the second base station, where the wake-up instruction is used to instruct the second base station to start up. 
     It should be noted that the UE in this embodiment is UE that supports carrier aggregation, where the UE that supports carrier aggregation may support services of two carriers at the same time. For example, when the UE keeps being connected to the first base station, the carrier corresponding to the second base station may be used as a secondary component carrier. When the UE is at an edge of the coverage scope of the second base station, the first base station may send the activation instruction to the UE, where the activation instruction is used by the UE to activate the carrier corresponding to the second base station. 
     It should be noted that after the first base station sends the wake-up instruction to the second base station and sends the activation instruction to the UE, step  714  and/or step  715  continue/continues to be performed. 
     Step  713 : When determining not to start up the second base station, the first base station does not send the wake-up instruction to the second base station and does not send the activation instruction to the UE. 
     When the first base station determines, by using the handover decision algorithm, that the first measurement result or the second measurement result corresponding to the second base station does not meet the requirement, in this case the first base station does not send the wake-up instruction to the second base station and does not send the activation instruction to the UE. It may be understood that in this embodiment, the first base station continues to provide a service for the UE. After the first base station determines not to start up the second base station, step  716  continues to be performed. 
     It should be noted that either step  712  or step  713  is performed, and the two steps cannot be performed at the same time. In  FIG. 7 , step  713  is indicated by a dashed box, or step  712  may be indicated by a dashed box, where a dashed box indicates that this step is an optional step. Certainly, an optional relationship may also be indicated in another manner, and a manner that indicates the optional relationship is not limited in this embodiment of the present invention. 
     Step  714 : The second base station starts up after receiving the wake-up instruction. 
     When the second base station starts up according to the wake-up instruction, it may be considered that the second base station enters an activated state. 
     Step  715 : The UE activates, according to the activation instruction, a carrier corresponding to the second base station. 
     After the UE activates the carrier corresponding to the second base station according to the activation instruction sent by the first base station, the second base station may provide a service for the UE. 
     It should be noted that there is no order between step  714  and step  715 . Certainly, step  715  may be performed first, and then step  714  is performed; or step  714  and step  715  are performed at the same time. 
     Step  716 : When the second base station does not receive the wake-up instruction within a second predetermined time, stop sending the RRM-RS signal. 
     In this embodiment, an entity for setting the second predetermined time is not limited. For example, the second predetermined time may be a time set by the second base station, or the second predetermined time may be a time set by the first base station. For example, when not starting the handover operation, the first base station may send a stop instruction to the second base station, where the stop instruction includes the second predetermined time. The second predetermined time may be in a unit of millisecond. For example, the second predetermined time may be 200 ms. In this embodiment, a range of the second predetermined time is not limited. After waiting the second predetermined time, when the second base station still does not receive the wake-up instruction sent by the first base station, the second base station enters the sleep state again, that is, the second base station sends only the DRS signal and stops sending the RRM-RS signal. 
     Step  717 : When the UE moves out of a coverage scope of the second base station, and there is no other UE within the scope, the second base station enters a sleep state again. 
     When the UE moves out of the coverage scope of the second base station, a handover operation is performed between the second base station and a base station corresponding to a scope to be entered by the UE. When the UE enters a coverage scope of the first base station, a handover operation is directly performed between the second base station and the first base station; or when the UE enters a coverage scope of another micro base station, the second base station, the UE, and the micro base station continue to perform a procedure of step  701  to step  716 . 
     In the method for assisting a terminal in measuring according to this embodiment of the present invention, correct measurement on signal strength of a micro base station may be implemented, thereby preventing UE from incorrectly determining the signal strength of the micro base station and achieving objectives of reducing power and reducing interference to a neighboring cell. 
     As shown in  FIG. 8 , an embodiment of the present invention provides another method for assisting a terminal in measuring, and the method includes the following steps: 
     Step  801 : After sending a DRS signal, a second base station sends an RRM-RS signal for a third predetermined time, and then continues to send a DRS signal in such a cycle. 
     In this embodiment, the second base station may be a micro base station. In this case, it may be considered that the second base station enters a sleep state. In the sleep state, the second base station periodically sends a DRS signal and an RRM-RS signal. The DRS signal includes ID information of a cell formed by the second base station, frequency channel number information of the second base station, and frequency domain information, time domain information, and sequence information of an RRM-RS signal. The ID information of the cell formed by the second base station includes a cell ID and/or a cell virtual ID. The second base station may reuse an existing synchronization signal, such as a PSS signal or an SSS signal; or the second base station may newly define a synchronization signal: an NDRS signal, and in this case, a sending period of the NDRS signal may be greater than or equal to a sending period of the existing synchronization signal. For example, the sending period of the existing synchronization signal may be 5 ms. The RRM-RS signal may be a CRS signal, or the RRM-RS signal may be a CSI-RS signal. 
     The third predetermined time is a time within a period of sending the DRS signal except a time of sending the DRS signal or a predetermined time within a period of sending the DRS signal. For example, a period of sending the DRS signal by the second base station is used as an example for description. As shown in  FIG. 4( a ) , the period of sending the DRS signal by the second base station is 1 s. After sending a DRS signal, the second base station starts to send an RRM-RS signal, and then continues to send a DRS signal; the second base station sends signals in this cycle. Alternatively, as shown in  FIG. 4( b ) , the period of sending the DRS signal by the second base station is 1 s. After sending a DRS signal, the second base station sends an RRM-RS signal of 200 ms, and then the second base station enters a cycle of a next period to continue to send a DRS signal. It should be noted that for the RRM-RS signal of 200 ms sent between the two DRS signals, a start time of sending the RRM-RS signal by the second base station is not limited in this embodiment. For ease of description, in  FIG. 4( b ) , the RS signal starts to be sent in 400 ms after the DRS signal is sent, that is, there is an interval of 400 ms between the RRM-RS signal and the two DRS signals. 
     Step  802 : UE receives the DRS signal and the RRM-RS signal that are sent by the second base station. 
     After the second base station sends the RRM-RS signal, optionally, the UE may directly receive the RRM-RS signal after detecting the DRS signal sent by the second base station; or the UE needs to wait a first predetermined time set by a timer on the UE and then starts to receive the RRM-RS signal after detecting the DRS signal sent by the second base station. The first predetermined time may be in a unit of millisecond. For example, the first predetermined time may be 20 ms. Certainly, the time set by the timer on the UE is not limited in this embodiment. Alternatively, the UE starts to receive the RRM-RS signal after receiving a first control instruction sent by a first base station; or the UE starts to receive the RRM-RS signal after receiving a second control instruction sent by the second base station. 
     It should be noted that for description of the first control instruction and the second control instruction in this step, refer to  FIG. 5 , and details are not described herein again. 
     Step  803 : The UE performs measurement on the second base station according to the RRM-RS signal to obtain a measurement result and sends the measurement result to a first base station. 
     When the RRM-RS signal is a CRS signal, the UE performs RRM measurement on the second base station according to the CRS signal to obtain a first measurement result, where the first measurement result includes RSRP and RSRQ; or when the RRM-RS signal is a CSI-RS signal, the UE performs RRM measurement on the second base station according to the CSI-RS signal to obtain a second measurement result, where the second measurement result includes CSI-RSRP. Then, the UE sends the RSRP and the RSRQ, or the CSI-RSRP to the first base station. 
     Step  804 : The first base station determines, according to the measurement result, whether the second base station needs to start up. 
     The first base station may analyze the first measurement result or the second measurement result by using a handover decision algorithm to determine whether the first base station needs to start a handover operation. For a process of using the handover decision algorithm by the first base station, refer to detailed description of step  509  in  FIG. 5 , and details are not described herein again. 
     Step  805 : When determining to start up the second base station, the first base station sends a wake-up instruction to the second base station. 
     When the first base station determines, by using the handover decision algorithm, that the first measurement result or the second measurement result corresponding to the second base station meets a requirement, in this case the first base station starts the handover operation and sends the wake-up instruction to the second base station, where the wake-up instruction is used to instruct the second base station to start up. 
     Optionally, when the UE is UE that supports carrier aggregation, the first base station sends the wake-up instruction to the second base station and sends an activation instruction to the UE, so that the UE activates, according to the activation instruction, a carrier corresponding to the second base station. The UE that supports carrier aggregation may support services of two carriers at the same time. After the first base station determines to start up the second base station, step  807  continues to be performed. 
     Step  806 : When the first base station does not need to start up the second base station, the first base station does not send the wake-up instruction to the second base station. 
     When the first base station determines, by using the handover decision algorithm, that the first measurement result or the second measurement result corresponding to the second base station does not meet the requirement, in this case the first base station does not send the wake-up instruction to the second base station, and optionally, when the UE is UE that supports carrier aggregation, the first base station does not send the activation instruction to the UE. It may be understood that in this embodiment, the first base station continues to provide a service for the UE. After the first base station determines not to start up the second base station, step  808  continues to be performed. 
     It should be noted that either step  805  or step  806  is performed, and the two steps cannot be performed at the same time. In  FIG. 8 , step  806  is indicated by a dashed box, or step  805  may be indicated by a dashed box, where a dashed box indicates that this step is an optional step. Certainly, an optional relationship may also be indicated in another manner, and a manner that indicates the optional relationship is not limited in this embodiment of the present invention. 
     Step  807 : The second base station starts up after receiving the wake-up instruction. 
     When the second base station starts up according to the wake-up instruction, it may be considered that the second base station enters an activated state. 
     The handover operation is performed between the second base station in the activated state and the first base station, where the handover operation may be an intra-frequency handover operation, or the handover operation may be an inter-frequency handover operation. For description of the intra-frequency handover operation or the inter-frequency handover operation, refer to detailed description of step  509  in  FIG. 5 , and details are not described herein again. 
     Optionally, when the UE is UE that supports carrier aggregation, the UE activates, according to the activation instruction sent by the first base station, the carrier corresponding to the second base station, so that the second base station can provide a service for the UE. 
     After the second base station serves the UE, step  809  continues to be performed. 
     Step  808 : When the second base station does not receive the wake-up instruction within a second predetermined time, stop sending the RRM-RS signal. 
     In this embodiment, an entity for setting the second predetermined time is not limited. For example, the second predetermined time may be a time set by the second base station, or the second predetermined time may be a time set by the first base station. In this embodiment, a range of the second predetermined time is not limited. After waiting the second predetermined time, when the second base station still does not receive the wake-up instruction sent by the first base station, the second base station enters the sleep state again, that is, the second base station sends only the DRS signal and stops sending the RRM-RS signal. 
     Step  809 : When the UE moves out of a coverage scope of the second base station, and there is no other UE within the scope, the second base station enters a sleep state again. 
     When the UE moves out of the coverage scope of the second base station, a handover operation is performed between the second base station and a base station corresponding to a scope to be entered by the UE. When the UE enters a coverage scope of the first base station, a handover operation is directly performed between the second base station and the first base station; or when the UE enters a coverage scope of another micro base station, the second base station, the UE, and the micro base station continue to perform a procedure of step  801  to step  808 . 
     In the method for assisting a terminal in measuring according to this embodiment of the present invention, correct measurement on signal strength of a micro base station may be implemented, thereby preventing UE from incorrectly determining the signal strength of the micro base station and achieving objectives of reducing power and reducing interference to a neighboring cell. 
     As shown in  FIG. 9 , an embodiment of the present invention provides an apparatus for assisting a terminal in measuring, including: a receiving module  901 , a determining module  902 , and a processing module  903 . The apparatus may be a first base station, and the first base station may be a macro base station. 
     The receiving module  901  is configured to receive a measurement result for a second base station and sent by UE, where the first base station provides a service for the UE; and provide the measurement result for the determining module  902 . 
     The second base station is a micro base station. The macro base station has a strong signal, a wide coverage scope, heavy traffic to bear, and a large floor area; the micro base station has low power, a small floor area, a small signal coverage scope, easy planning, and a capability of increasing a hotspot capacity. The measurement result of the second base station includes RSRP and RSRQ. 
     The determining module  902  is configured to determine, according to the measurement result received by the receiving module  901 , whether a handover operation needs to be started, and provide a result of the determining for the processing module  903 . 
     The determining module  902  may analyze the measurement result by using a handover decision algorithm to determine whether the processing module  903  needs to start the handover operation. When a value of the RSRP in the measurement result is greater than or equal to a threshold CH 1 , and when a value of the RSRQ is greater than or equal to a threshold CH 2 , the processing module  903  determines to start the handover operation. On the contrary, when the value of the RSRP in the measurement result is less than the threshold CH 1 , and/or when the value of the RSRQ is less than the threshold CH 2 , the processing module  903  determines not to start the handover operation. 
     The processing module  903  is configured to: instruct, according to the result determined by the determining module  902  that the handover operation needs to be started, the second base station to start up, and hand over the UE to the second base station for a service provided by the second base station. 
     When the determining module  902  determines, by using the handover decision algorithm, that the measurement result corresponding to the second base station meets a requirement, in this case the processing module  903  starts the handover operation and sends a wake-up instruction to the second base station, where the wake-up instruction is used to instruct the second base station to start up. 
     Further, as shown in  FIG. 10 , the processing module  903  of the apparatus includes a sending unit  9031  and a handover unit  9032 . 
     The sending unit  9031  sends the wake-up instruction to the second base station according to the result determined by the determining module  902  that the handover operation needs to be started. 
     After the sending unit  9031  sends the wake-up instruction to the second base station, the handover unit  9032  is configured to hand over the UE to the second base station after the second base station starts up. 
     Optionally, the processing module  903  is further configured to skip sending the wake-up instruction to the second base station according to the result determined by the determining module that the handover operation does not need to be started. 
     It should be noted that when the UE is UE that supports carrier aggregation, the determining module  902  determines, according to the measurement result received by the receiving module  901 , whether an activation instruction needs to be sent to the UE that supports carrier aggregation, so that the UE activates, according to the activation instruction, a carrier corresponding to the second base station. 
     It should be noted that because content such as specific implementation processes of various modules and information exchange between the various modules in the apparatus shown in  FIG. 9  and  FIG. 10  is based on a same invention concept as the method embodiments of the present invention, refer to the method embodiments, and details are not described herein again. 
     In the apparatus for assisting a terminal in measuring according to this embodiment of the present invention, a receiving module receives a measurement result for a second base station sent by user equipment UE, where the first base station provides a service for the UE, and the receiving module provides the measurement result for a determining module; the determining module determines, according to the measurement result received by the receiving module, whether a handover operation needs to be started, and provides a result of the determining for a processing module; the processing module instructs, according to the result determined by the determining module that the handover operation needs to be started, the second base station to start up, and hands over the UE to the second base station for a service provided by the second base station. Compared with a problem in the prior art that after the UE sends an uplink signal, the second base station starts up according to the uplink signal, but a situation in which the UE does not enter a coverage scope of the second base station may occur, which causes a waste of resources, in this embodiment of the present invention, accurate determining may be implemented on a signal of the second base station to determine whether the second base station needs to start up to provide a service for the UE, thereby reducing an unnecessary resource waste of the second base station. 
     As shown in  FIG. 11 , an embodiment of the present invention provides another apparatus for assisting a terminal in measuring, including: a detection module  1101 , a receiving module  1102 , a measurement module  1103 , and a sending module  1104 ; the apparatus may be UE. 
     The detection module  1101  is configured to detect a DRS signal sent by a second base station. 
     In this embodiment, the second base station may be a micro base station. The micro base station has features such as low power, a small floor area, a small signal coverage scope, easy planning, and a capability of increasing a hotspot capacity. 
     The receiving module  1102  is configured to: after the detection module  1101  detects the DRS signal, receive an RRM-RS signal sent by the second base station, and provide the RRM-RS signal for the measurement module  1103 . 
     The RRM-RS signal may be a CRS signal, or the RRM-RS signal may be a CSI-RS signal. 
     After the receiving module  1102  receives the RRM-RS signal, the measurement module  1103  is configured to perform, according to the RRM-RS signal received by the receiving module  1101 , measurement on the second base station to obtain a measurement result, and provide the measurement result for the sending module  1104 . 
     When the RRM-RS signal is a CRS signal, the UE performs RRM measurement on the second base station according to the CRS signal to obtain a first measurement result, where the first measurement result includes RSRP and RSRQ; or when the RRM-RS signal is a CSI-RS signal, the UE performs RRM measurement on the second base station according to the CSI-RS signal to obtain a second RRM measurement result, where the second measurement result includes CSI-RSRP. 
     After the measurement module  1103  obtains the measurement result, the sending module  1104  is configured to send the first measurement result or the second measurement result obtained by the measurement module  1103  to a first base station, so that the first base station determines, according to the first measurement result or the second measurement result, whether to instruct the second base station to start up, and hands over the UE to the second base station. 
     Specifically, the sending module  1104  sends the RSRP and the RSRQ, or the CSI-RSRP to the first base station. 
     Further, as shown in  FIG. 12 , the apparatus further includes a generating module  1105 , an obtaining module  1106 , and an activation module  1107 . 
     The detection module  1101  detects, on a carrier corresponding to the second base station, the DRS signal sent by the second base station, and provides the DRS signal for the generating module  1105  or the obtaining module  1106 . 
     The DRS signal is a sparse synchronization signal in a time domain, and a time period is in seconds or longer. Generally, the second base station periodically sends a DRS signal in a sleep state. The DRS signal includes ID information of a cell formed by the second base station, frequency channel number information of the second base station, and frequency domain information, time domain information, and sequence information of an RRM-RS signal. The ID information of the cell formed by the second base station includes a cell ID and/or a cell virtual ID. The DRS signal may be an existing synchronization signal, such as a PSS signal or an SSS signal; or the DRS signal may be a new discovery pilot (New Discovery Reference Signal, NDRS) signal that is newly defined by the second base station. 
     It should be noted that the apparatus may include the generating module  1105  and/or the obtaining module  1106 . 
     Optionally, the generating module  1105  generates an uplink signal according to the DRS signal detected by the detection module  1101 , and provides the uplink signal for the sending module  1104 . 
     The uplink signal may be a RACH signal, or the uplink signal may be an SRS signal. The uplink signal is used to instruct the second base station to send the RRM-RS signal. 
     The sending module  1104  sends, according to the uplink signal generated by the generating module  1105 , the uplink signal to the second base station on the carrier corresponding to the second base station, so that the second base station starts to send the RRM-RS signal according to the uplink signal. 
     Optionally, the obtaining module  1106  parses the DRS signal that is sent by the second base station and detected by the detection module  1101 , to obtain first information of the second base station, and provides the first information for the sending module  1104 . 
     The first information is used to instruct the first base station to trigger the second base station to send the RRM-RS signal, where the first information includes the ID information of the second base station and the frequency channel number information of the second base station. 
     The sending module  1104  sends the first information obtained by the obtaining module  1106  to the first base station, so that the first base station sends an instruction that triggers the second base station to send the RRM-RS signal, that is, the instruction is a trigger instruction. 
     It should be noted that when the UE is UE that supports carrier aggregation, the receiving module  1102  receives an activation instruction sent by the first base station and provides the activation instruction for the activation module  1107 . 
     The activation module  1107  activates, according to the activation instruction that is sent by the first base station and received by the receiving module  1102 , the carrier corresponding to the second base station, so that the UE can be served by the first base station and the second base station at the same time. 
     It should be noted that because content such as specific implementation processes of various modules and information exchange between the various modules in the apparatus shown in  FIG. 11  and  FIG. 12  is based on a same invention concept as the method embodiments of the present invention, refer to the method embodiments, and details are not described herein again. 
     In the apparatus for assisting a terminal in measuring according to this embodiment of the present invention, a detection module detects a discovery pilot DRS signal sent by a second base station; after the detection module detects the DRS signal, a receiving module receives a radio resource management pilot RRM-RS signal sent by the second base station, and provides the RRM-RS signal for a measurement module; the measurement module performs measurement on the second base station according to the RRM-RS signal received by the receiving module to obtain a measurement result, and provides the measurement result for a sending module; the sending module sends the measurement result obtained by the measurement module to a first base station, so that the first base station instructs, according to the measurement result, the second base station to start up, and hands over UE to the second base station. Compared with a problem in the prior art that because a DRS signal is a sparse synchronization signal in a time domain, and a time period is in seconds or longer, the UE performs erroneous determining on a signal of the second base station, in this embodiment of the present invention, correct measurement on signal strength of a micro base station may be implemented, thereby preventing the UE from incorrectly determining the signal strength of the micro base station. 
     As shown in  FIG. 13 , an embodiment of the present invention provides another apparatus for assisting a terminal in measuring, including: a first sending module  1301  and a second sending module  1302 . The apparatus may be a second base station, and the second base station may be a micro base station. 
     The first sending module  1301  is configured to periodically send a DRS signal. 
     In a sleep state, the second base station may reduce power and reduce interference to a neighboring cell. It should be noted that when the second base station is in the sleep state, the first sending module  1301  periodically sends a DRS signal. The DRS signal is a sparse synchronization signal in a time domain, and a time period is in seconds or longer. The DRS signal includes ID information of a cell formed by the second base station, frequency channel number information of the second base station, and frequency domain information, time domain information, and sequence information of an RRM-RS signal. The ID information of the cell formed by the second base station includes a cell ID and/or a cell virtual ID. The first sending module  1301  may reuse an existing synchronization signal, such as a PSS signal or an SSS signal; or the first sending module  1301  may send a newly defined NDRS signal, and in this case, a sending period of the NDRS signal may be greater than or equal to a sending period of the existing synchronization signal. For example, the sending period of the existing synchronization signal may be 5 ms. 
     The second sending module  1302  is configured to send the RRM-RS signal, so that UE receives the RRM-RS signal and performs measurement on the second base station according to the RRM-RS signal. 
     The RRM-RS signal may be a CRS signal, or the RRM-RS signal may be a CSI-RS signal, so that the UE performs the measurement on the second base station according to a different type of the RRM-RS signal. 
     Further, as shown in  FIG. 14 , the apparatus further includes a receiving module  1303 , an activation module  1304 , and a processing module  1305 . 
     The receiving module  1303  receives an uplink signal sent by the UE, and provides the uplink signal for the second sending module  1302 , where the uplink signal is used to trigger the second base station to send the RRM-RS signal, and the uplink signal is an uplink random access RACH signal or the uplink signal is an uplink sounding pilot SRS signal; or the receiving module  1303  receives a trigger instruction sent by a first base station, and provides the trigger instruction for the second sending module  1302 , where the trigger instruction is used to trigger the second base station to send the RRM-RS signal. 
     After the receiving module  1303  receives the uplink signal sent by the UE or receives the trigger instruction sent by the first base station, the second sending module  1302  starts to send the RRM-RS signal according to the uplink signal that is sent by the UE and received by the receiving module  1303 ; or the second sending module  1302  starts to send the RRM-RS signal according to the trigger instruction that is sent by the first base station and received by the receiving module  1303 ; or after the first sending module sends a DRS signal, the second sending module sends the RRM-RS signal for a third predetermined time, where the third predetermined time is a time within a period of sending the DRS signal except a time of sending the DRS signal or a predetermined time within a period of sending the DRS signal. For an implementation period of sending the DRS signal by the second base station, refer to  FIG. 4 , and details are not described herein again. 
     The receiving module  1303  receives a wake-up instruction sent by the first base station, and provides the wake-up instruction for the activation module  1304 ; the activation module  1304  starts up the second base station according to the wake-up instruction received by the receiving module  1303 . In this case, it may be considered that the second base station enters an activated state. 
     When the receiving module  1303  does not receive the wake-up instruction within a second predetermined time, the processing module  1305  stops sending the RRM-RS signal. 
     It should be noted that the UE receives the RRM-RS signal, performs measurement on signal strength of the second base station according to the RRM-RS signal, and sends an obtained measurement result to the first base station; the first base station determines the measurement result by using a handover decision algorithm to determine whether the second base station may start up. When determining that the second base station may start up, the first base station sends the wake-up instruction to the receiving module  1303  of the second base station. 
     It should be noted that because content such as specific implementation processes of various modules and information exchange between the various modules in the apparatus shown in  FIG. 13  and  FIG. 14  is based on a same invention concept as the method embodiments of the present invention, refer to the method embodiments, and details are not described herein again. 
     In the apparatus for assisting a terminal in measuring according to this embodiment of the present invention, a first sending module periodically sends a discovery pilot DRS signal; a second sending module sends a radio resource management pilot RRM-RS signal, so that user equipment UE receives the RRM-RS signal, and performs measurement on a second base station according to the RRM-RS signal. Compared with a problem in the prior art that the second base station sends only the DRS signal, causing that UE incorrectly determines signal strength of the second base station, or the second base station sends both the DRS signal and the RRM-RS signal, causing a waste of resources, in this embodiment of the present invention, correct measurement on signal strength of a micro base station may be implemented, thereby preventing the UE from incorrectly determining the signal strength of the micro base station and achieving objectives of reducing power and reducing interference to a neighboring cell. 
     As shown in  FIG. 15 , an embodiment of the present invention provides another apparatus for assisting a terminal in measuring, including: a memory  1501 , a receiver  1502 , a processor  1503 , and a transmitter  1504 . The apparatus may be a first base station, and the first base station may be a macro base station. 
     The memory  1501  is configured to store information including a program routine. 
     The receiver  1502  is configured to receive a measurement result for a second base station and sent by UE, where the first base station provides a service for the UE; and provide the measurement result for the processor  1503 . 
     The second base station is a micro base station. The macro base station has a strong signal, a wide coverage scope, heavy traffic to bear, and a large floor area; the micro base station has low power, a small floor area, a small signal coverage scope, easy planning, and a capability of increasing a hotspot capacity. The measurement result of the second base station includes RSRP and RSRQ. 
     The processor  1503  is connected to the memory  1501 , the receiver  1502 , and the transmitter  1504 , is configured to control execution of the program routine, and is specifically configured to determine, according to the measurement result received by the receiver  1502 , whether a handover operation needs to be started; when the handover operation needs to be started, instruct the second base station to start up, and hand over the UE to the second base station for a service provided by the second base station. 
     The processor  1503  may analyze the measurement result by using a handover decision algorithm to determine whether the processor  1503  needs to start the handover operation. When a value of the RSRP in the measurement result is greater than or equal to a threshold CH 1 , and when a value of the RSRQ is greater than or equal to a threshold CH 2 , the processor  1503  determines to start the handover operation, and then the transmitter  1504  sends a wake-up instruction to the second base station, where the wake-up instruction is used to instruct the second base station to start up. When the second base station starts up, it may be considered that the second base station enters an activated state. When the second base station is in the activated state, the processor  1503  hands over the UE to the second base station. It may be understood that the handover operation is an inter-frequency handover operation, or the handover operation is an intra-frequency handover operation. 
     On the contrary, when the value of the RSRP in the measurement result is less than the threshold CH 1 , and/or when the value of the RSRQ is less than the threshold CH 2 , the processor  1503  determines not to start the handover operation. 
     It should be noted that when the UE is UE that supports carrier aggregation, the processor  1503  determines, according to the measurement result received by the receiver  1502 , whether an activation instruction needs to be sent to the UE that supports carrier aggregation, so that the UE activates, according to the activation instruction, a carrier corresponding to the second base station. 
     It should be noted that because content such as specific implementation processes of various modules and information exchange between the various modules in the apparatus shown in  FIG. 15  is based on a same invention concept as the method embodiments of the present invention, refer to the method embodiments, and details are not described herein again. 
     In the apparatus for assisting a terminal in measuring according to this embodiment of the present invention, correct measurement on signal strength of a micro base station may be implemented, thereby preventing UE from incorrectly determining the signal strength of the micro base station and achieving objectives of reducing power and reducing interference to a neighboring cell. 
     As shown in  FIG. 16 , an embodiment of the present invention provides another apparatus for assisting a terminal in measuring, including: a memory  1601 , a receiver  1602 , a processor  1603 , and a transmitter  1604 ; the apparatus may be UE. 
     The memory  1601  is configured to store information including a program routine. 
     The receiver  1602  is configured to receive an RRM-RS signal sent by a second base station, and provide the RRM-RS signal for the processor  1603 . 
     The RRM-RS signal is a CRS signal, or the RRM-RS signal is a channel state information pilot CSI-RS signal. It may be understood that the second base station is a micro base station. 
     After the receiver  1602  receives the RRM-RS signal, the processor  1603  that is connected to the memory  1601 , the receiver  1602 , and the transmitter  1604  is configured to control execution of the program routine, and is specifically configured to perform, according to the RRM-RS signal received by the receiver  1602 , measurement on the second base station to obtain a measurement result, and provide the measurement result for the transmitter  1604 . 
     When the RRM-RS signal is a CRS signal, the UE performs RRM measurement on the second base station according to the CRS signal to obtain a first measurement result, where the first measurement result includes RSRP and RSRQ; or when the RRM-RS signal is a CSI-RS signal, the UE performs RRM measurement on the second base station according to the CSI-RS signal to obtain a second RRM measurement result, where the second measurement result includes CSI-RSRP. 
     After the processor  1603  obtains the first measurement result or the second measurement result, the transmitter  1604  is configured to send the first measurement result or the second measurement result obtained by the processor  1603  to a first base station, so that the first base station determines, according to the first measurement result or the second measurement result, whether to instruct the second base station to start up, and hands over the UE to the second base station. 
     Specifically, the transmitter  1604  sends the RSRP and the RSRQ to the first base station. 
     Further, the receiver  1602  is further configured to start to receive the RRM-RS signal after waiting for a first predetermined time; or 
     the receiver  1602  is further configured to receive a first control instruction sent by the first base station, and start to receive the RRM-RS signal according to the first control instruction, where the first control instruction is used to instruct the UE to receive the RRM-RS signal; or 
     the receiver  1602  is further configured to receive a second control instruction sent by the second base station, and start to receive the RRM-RS signal according to the second control instruction, where the second control instruction is used to instruct the UE to receive the RRM-RS signal. 
     Further, before the receiver  1602  receives the RRM-RS signal, the processor  1603  is further configured to detect, on a carrier corresponding to the second base station, the DRS signal sent by the second base station; then, generate an uplink signal according to the DRS signal, and provide the uplink signal for the transmitter  1604 . 
     The transmitter  1604  sends, according to the uplink signal generated by the processor  1603 , the uplink signal to the second base station on the carrier corresponding to the second base station, so that the second base station starts to send the RRM-RS signal according to the uplink signal. 
     The uplink signal is a RACH signal, or the uplink signal is an SRS signal. 
     Further, the processor  1603  is further configured to parse the DRS signal sent by the second base station, to obtain first information of the second base station, and provide the first information for the transmitter  1604 , where the first information is used to instruct the first base station to trigger the second base station to send the RRM-RS signal. 
     The transmitter  1604  sends the first information obtained by the processor  1603  to the first base station, so that the first base station sends an instruction that triggers the second base station to send the RRM-RS signal, that is, the instruction is a trigger instruction. 
     It should be noted that when the UE is UE that supports carrier aggregation, the receiver  1602  is further configured to receive an activation instruction sent by the first base station, and provide the activation instruction for the processor  1603 . 
     The processor  1603  activates, according to the activation instruction that is sent by the first base station and received by the receiver  1602 , the carrier corresponding to the second base station, so that the UE can be served by the first base station and the second base station at the same time. 
     It should be noted that because content such as specific implementation processes of various modules and information exchange between the various modules in the apparatus shown in  FIG. 16  is based on a same invention concept as the method embodiments of the present invention, refer to the method embodiments, and details are not described herein again. 
     In the apparatus for assisting a terminal in measuring according to this embodiment of the present invention, correct measurement on signal strength of a micro base station may be implemented, thereby preventing UE from incorrectly determining the signal strength of the micro base station and achieving objectives of reducing power and reducing interference to a neighboring cell. 
     As shown in  FIG. 17 , an embodiment of the present invention provides another apparatus for assisting a terminal in measuring, including: a memory  1701 , a transmitter  1702 , a receiver  1703 , and a processor  1704 ; the apparatus may be a second base station. 
     The memory  1701  is configured to store information including a program routine. 
     The transmitter  1702  is configured to periodically send a DRS signal, and send an RRM-RS signal, so that UE performs measurement on the second base station according to the RRM-RS signal after detecting the DRS signal. 
     The transmitter  1702  may reuse an existing synchronization signal, such as a PSS signal or an SSS signal; or the transmitter  1702  may send a newly defined NDRS signal. In this case, a sending period of the NDRS signal may be greater than or equal to a sending period of the existing synchronization signal. For example, the sending period of the existing synchronization signal may be 5 ms. 
     After the receiver  1703  receives an uplink signal sent by the UE and provides the uplink signal for the transmitter  1702 , the transmitter  1702  starts to send the RRM-RS signal according to the uplink signal that is sent by the UE and received by the receiver  1703 , where the uplink signal is used to trigger the second base station to send the RRM-RS signal, and the uplink signal may be a RACH signal or an SRS signal; or after the receiver  1703  receives a trigger instruction sent by a first base station and provides the trigger instruction for the transmitter  1702 , the transmitter  1702  starts to send the RRM-RS signal according to the trigger instruction that is sent by the first base station and received by the receiver  1703 , where the trigger instruction is used to trigger the second base station sends a message of the RRM-RS signal; or after sending a DRS signal, the transmitter  1702  sends the RRM-RS signal for a third predetermined time, where the third predetermined time is a time within a period of sending the DRS signal except a time of sending the DRS signal or a predetermined time within a period of sending the DRS signal. 
     The RRM-RS signal may be a CRS signal, or the RRM-RS signal may be a CSI-RS signal, so that the UE performs the measurement on the second base station according to a different type of the RRM-RS signal. 
     When the UE receives the RRM-RS signal, performs measurement on signal strength of the second base station according to the RRM-RS signal, and sends an obtained measurement result to the first base station, the first base station determines the measurement result by using a handover decision algorithm to determine whether the second base station may start up. When determining that the second base station may start up, the first base station sends a wake-up instruction to the receiver  1703  of the second base station. 
     The receiver  1703  receives the wake-up instruction sent by the first base station, and provides the wake-up instruction for the processor  1704 . 
     The processor  1704  is connected to the memory  1701 , the transmitter  1702 , and the receiver  1703 , is configured to control execution of the program routine, and is specifically configured to start up the second base station according to the wake-up instruction received by the receiver  1703 . 
     When the receiver  1703  does not receive the wake-up instruction within a second predetermined time, the processor  1704  stops sending the RRM-RS signal, where the second predetermined time is a time set by the second base station. 
     It should be noted that because content such as specific implementation processes of various modules and information exchange between the various modules in the apparatus shown in  FIG. 17  is based on a same invention concept as the method embodiments of the present invention, refer to the method embodiments, and details are not described herein again. 
     In the apparatus for assisting a terminal in measuring according to this embodiment of the present invention, correct measurement on signal strength of a micro base station may be implemented, thereby preventing UE from incorrectly determining the signal strength of the micro base station and achieving objectives of reducing power and reducing interference to a neighboring cell. 
     It may be clearly understood by a person skilled in the art that, for the purpose of convenient and brief description, division of the foregoing function modules is taken as an example for illustration. In actual application, the foregoing functions can be allocated to different function modules and implemented according to a requirement, that is, an inner structure of an apparatus is divided into different function modules to implement all or some of the functions described above. For a detailed working process of the foregoing system, apparatus, and unit, reference may be made to a corresponding process in the foregoing method embodiments, and details are not described herein again. 
     In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus, and method may be implemented in other manners. For example, the described apparatus embodiment is merely exemplary. For example, the module or unit division is merely logical function division and may be other division in actual implementation. For example, a plurality of units or components may be combined or integrated into another system, or some features may be ignored or not performed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections may be implemented by using some interfaces. The indirect couplings or communication connections between the apparatuses or units may be implemented in electronic, mechanical, or other forms. 
     The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one position, or may be distributed on a plurality of 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, functional units in the embodiments of the present invention may be integrated into one processing unit, or each of the units may exist alone physically, or two or more units are integrated into one unit. The integrated unit may be implemented in a form of hardware, or may be implemented in a form of a software functional unit. 
     When the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, the integrated unit may be stored in a computer-readable storage medium. Based on such an understanding, the technical solutions of the present invention essentially, or the part contributing to the prior art, or all or a part of the technical solutions may be implemented in the form of a software product. The software product is stored in a storage medium and includes several instructions for instructing a computer device (which may be a personal computer, a server, a network device, or the like) or a processor to perform all or a part of the steps of the methods described in the embodiments of the present invention. The foregoing storage medium includes: any medium that can store program code, such as a USB flash drive, a removable hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disc. 
     The foregoing descriptions are merely specific implementation manners of the present invention, but are not intended to limit the protection scope of the present invention. Any variation or replacement readily figured out by a person skilled in the art within the technical scope disclosed in the present invention shall fall within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.