CN104244318A - Method and device for adjusting time to trigger - Google Patents

Abstract

The present invention discloses a method for adjusting trigger time (TTT), which includes: when a mobile terminal (UE) is handed over, a target base station (TeNB) obtains handover assistance information of the UE, and determines the current time according to the handover assistance information of the UE. Handover weight for handover; TeNB sends a handover command to UE, and carries the above handover weight in the handover command; UE performs handover counting according to the handover weight in the handover command, and obtains the updated number of handovers; Adjust TTT. The invention also discloses the base station and the UE for adjusting the triggering time.

Description

Method and device for adjusting trigger time

technical field

The present application relates to mobile communication technologies, and in particular to a method and device for adjusting the trigger time of reporting a measurement report by a mobile communication device during a handover process.

Background technique

Cellular mobile phones have brought great convenience to people's communication. As an important organization in the field of mobile communication, the 3rd Generation Partnership Project (3GPP) has greatly promoted the standardization of the third generation mobile communication technology (The Third Generation, 3G). A few days ago, in order to meet the challenges of broadband access technology and meet the growing demand for new services, 3GPP launched the standardization of 3G Long Term Evolution (LTE) technology at the end of 2004, hoping to further improve spectrum efficiency and improve cell The performance of edge users, reducing system delay, and providing higher-speed access services for high-speed mobile users. The improved LTE (LTE-Advanced, LTE-A) technology is based on LTE technology, which doubles the spectrum bandwidth and doubles the data rate, providing more mobile users with higher speed and better performance services.

In the above-mentioned various mobile communication systems, mobility management of users in a connected (CONNECTED) state is particularly important. In order to manage the mobility of users in the connected state, the concept of handover is defined in the mobile communication system, which allows users in the connected state to switch from the current serving cell to other cells when certain conditions are met. If there is no handover, when the user moves out of the serving cell, the user may drop the call and reconnect to the new cell, which will seriously affect the service satisfaction of the user.

Generally speaking, handover mainly includes four steps: measurement, measurement report, handover decision, and handover execution. Among them, the measurement refers to the reference signal received power (Reference Signal Received Power, RSRP) or reference signal received quality (Reference Signal Received Quality, RSRQ) of the user to its serving cell and neighboring cells, or other signal strength parameters that can characterize the signal strength of the cell Take measurements. The measurement reporting refers to reporting the handover measurement report to the source base station when the handover measurement report reporting condition set by the measurement configuration is satisfied. The handover decision refers to that the source base station judges whether the user needs to perform handover and selects the target base station according to the handover measurement report. Handover execution mainly refers to the process in which the user disconnects from the source base station and establishes a connection with the target base station. It can be seen that, in the above-mentioned handover process, the handover measurement report reporting condition and the handover condition for judging whether to perform handover are related to whether a target base station with the best performance can be selected, so the setting of the handover measurement report reporting condition and the handover condition is very important. At present, the handover measurement report reporting conditions used in the LTE system are mostly based on event A3 measurement report reporting conditions, that is, when the mobile terminal (UE) measures the difference between the RSRP or RSRQ of a neighboring cell and the RSRP or RSRQ of the serving cell When the value is greater than the handover offset HO_margin configured by the serving cell (usually set to 3dB), start timing; if the above measurement report reporting conditions can be met within a predetermined period of time, the UE will report to the source base station to carry the serving cell And a handover measurement report of the signal strength parameter of the adjacent cell. Thereafter, the source base station will make a handover decision according to the serving cell carried in the handover measurement report reported by the user and the signal strength parameters of the neighboring cell. If the result of the handover decision is that handover is required, the handover execution process is further completed. The predetermined period of time mentioned in the above process is also called the trigger time (Time To Trigger, TTT) for triggering the reporting of the measurement report.

Those skilled in the art can understand that the time required for the entire handover process mainly includes: time required for TTT, handover decision, and handover execution. Wherein, the time required for handover decision and handover execution is basically fixed, while TTT is variable. Therefore, it can be considered that TTT is the main factor affecting the time required for the entire handover process. Usually, if the TTT is too long, the measurement report will be too late, which will greatly increase the handover failure rate when the UE moves fast; and if the TTT is too short, it will cause frequent handovers of the UE, resulting in a serious ping-pong effect .

In the existing LTE Release 9 (Rel-9) standard, the UE adjusts the TTT size through Mobility State Estimation (MSE). Specifically, the UE estimates its own moving speed according to the number of handovers within a certain period of time, and adjusts the size of the TTT according to its own moving speed. Usually, the faster the UE moves, the smaller the TTT is, allowing the UE to access the target cell faster to reduce the handover failure rate; the slower the UE moves, the larger the TTT is The switching conditions are made harsh to reduce the impact of the ping-pong effect. The above mobility state estimation method has been widely and effectively applied in the traditional homogeneous network (Homogeneous Network, HomoNet), but it is not suitable for application in the heterogeneous network (Heterogeneous Network, HetNet).

Heterogeneous network HetNet is a technology that can significantly improve system throughput and overall network efficiency. A heterogeneous network refers to a heterogeneous system in which at least one low power node (Low Power Node, LPN) is deployed in the coverage area of a high power node (High Power Node, HPN), forming different node types with the same coverage. Among them, HPN refers to base stations with high transmission power and large coverage radius, such as macrocell base stations, etc.; LPN refers to base stations with low transmission power and small coverage, such as small cell base stations, microcell base stations, millimeter cell base stations, etc. Femtocell base station and remote radio head (Remote Radio Head, RRH) or relay (Relay), etc.

In HetNet, because there may be multiple small cells covered by small cell base stations in a macro cell covered by a macro cell base station, the network density is greatly increased. In this case, multiple handovers may occur even though the UE moves at a slow speed in the macro cell. At this time, if the above-mentioned mobility state estimation method is applied, and only the number of handovers is used as the basis for judging the UE’s moving speed, the UE’s moving speed will be seriously overestimated, and the TTT will be adjusted too low, resulting in serious ping-pong effect.

Contents of the invention

In order to solve the above problem, the embodiment of the present invention proposes a method for adjusting the trigger time of reporting measurement report, so as to realize accurate adjustment of TTT.

The method for adjusting TTT proposed by the embodiment of the present invention includes: when the mobile terminal UE is handed over, the target base station TeNB obtains the handover assistance information of the UE; the TeNB determines the handover weight of this handover according to the handover assistance information of the UE; and the TeNB Send a handover command to the UE, and carry the handover weight in the handover command.

Wherein, the auxiliary information of UE handover includes handover history information of the UE.

The above method further includes: the source base station SeNB stores the handover history information of the UE, and sends the handover history information of the UE stored by itself to the TeNB after the handover decision is made.

The above method may further include: the mobility management entity MME stores the handover history information of the UE, and sends the handover history information of the UE stored by itself to the TeNB after the handover decision is made.

Wherein, determining the handover weight of the current handover by the TeNB according to the handover assistance information of the UE includes: determining a first handover weight according to the handover history information of the UE, and using the determined first handover weight as the handover weight of the current handover.

The UE handover assistance information includes the deployment information of the target cell; the TeNB determining the handover weight of this handover according to the UE handover assistance information includes: determining the second handover weight according to the deployment information of the target cell, and applying the determined second handover weight As the switch weight of this switch.

The auxiliary information of UE handover includes the handover history information of the UE and the deployment information of the target cell; the determination of the handover weight of this handover by the TeNB according to the handover auxiliary information of the UE includes: determining the first handover weight according to the handover history information of the UE weight; determining the second handover weight according to the deployment information of the target cell; and selecting the minimum value of the first handover weight and the second handover weight as the handover weight of this handover.

Determining the first handover weight according to the handover history information of the UE includes: if it is determined according to the handover history information of the UE that within a predetermined period of time, the UE is ready to handover back to cell A after handover from cell A, then Set the first toggle weight to 0; otherwise, set the first toggle weight to 1.

Determining the second handover weight according to the deployment information of the target cell includes: determining the second handover weight according to the size information of the target cell.

The handover assistance information of the UE further includes deployment information of the source cell; the method further includes: judging whether the coverage of the source cell and the target cell are the same or whether the coverage of the source cell is judged according to the deployment information of the source cell and the deployment information of the target cell If it is within the coverage of the target cell, then set the second handover weight to 0.

The method for adjusting TTT provided by another embodiment of the present invention includes: the UE performs handover counting according to the handover weight carried in the handover command to obtain an updated number of handovers; and the UE adjusts TTT according to the updated number of handovers.

The UE performing handover counting according to the handover weight in the handover command includes: UE performing handover counting according to the following formula:

Among them, HO_count represents the number of handovers recorded by the UE; Represents the switching weight carried in the switching command.

The TTT method provided by another embodiment of the present invention includes: the UE determines the weight of this handover according to its own handover assistance information; the UE performs handover counting according to the handover weight to obtain the updated number of handovers; Adjust TTT.

The handover assistance information includes handover history information stored by the UE itself; determining the handover weight of this handover by the UE according to its own handover assistance information includes: determining the first handover weight by the UE according to the handover history information stored by itself, and applying the determined The first switching weight is used as the switching weight of this switching.

The handover assistance information includes the deployment information of the target cell; the UE determining the handover weight of this handover according to its own handover assistance information includes: the UE determining the second handover weight according to the TeNB deployment information, and using the determined second handover weight As the switch weight of this switch.

The handover assistance information includes the handover history information of the UE and the deployment information of the target cell provided by the target base station TeNB; the determination of the weight of this handover by the UE according to its own handover assistance information includes: the UE determines the first handover according to the handover history information stored by itself. weight; the UE determines the second handover weight according to the deployment information of the target cell provided by the TeNB; and selects the minimum value of the first handover weight and the second handover weight as the handover weight of the current handover.

The determining of the first handover weight by the UE according to the handover history information stored by itself includes: if it is determined according to the handover history information of the UE that within a predetermined period of time, the UE is ready to handover back to the cell A after being handed over from the cell A, then Set the first toggle weight to 0; otherwise, set the first toggle weight to 1.

The UE determining the second handover weight according to the deployment information of the target cell includes: determining the second handover weight according to the size information of the target cell.

The handover assistance information of the UE further includes deployment information of the source cell; the method further includes: judging whether the coverage of the source cell and the target cell are the same or whether the coverage of the source cell is judged according to the deployment information of the source cell and the deployment information of the target cell If it is within the coverage of the target cell, then set the second handover weight to 0.

The handover count performed by the UE according to the handover weight includes: the UE performs the handover count according to the following formula:

Among them, HO_count represents the number of handovers recorded by the UE; Represents the switch weight of this switch.

The method for adjusting TTT provided by another embodiment of the present invention includes: pre-setting the initial value TTT ₀ of TTT; pre-setting n thresholds thre ₁ , thre ₂ ,..., _thren and n coefficients corresponding to the n thresholds factor ₁ , factor ₂ , ..., factor _n , satisfying 0<thre1<thre2<...<thren and 1>factor ₁ >factor ₂ >...>factor _n >0; among them, n is a natural number; UE performs handover counting, every time For one handover, the handover counter value HO_count is increased by 1; the UE adjusts the n thresholds or the n coefficients according to the handover assistance information of the UE; if thr _k <HO_count<thre _k+1 is satisfied, TTT=TTT ₀ ×factor _k , where k<n, and k is a natural number; if HO_count>thre _n is satisfied, TTT=TTT ₀ ×factor _n .

The base station provided by the embodiment of the present invention includes: a handover assistance information acquisition module, which is used to obtain handover assistance information of a user terminal UE; a handover weight determination module, which is used to determine the handover weight of this handover according to the handover assistance information of the UE; and a handover command A sending module, configured to send a handover command to the UE, and carry the handover weight in the handover command.

The UE provided by the embodiment of the present invention includes: a handover weight receiving module, configured to extract handover weights from a received handover command; a handover counting module, used to count handovers according to the handover weights in the handover command, and obtain an updated number of handovers; And a trigger time adjustment module, configured to adjust the trigger time TTT according to the updated switching times.

Another base station provided by an embodiment of the present invention includes: a handover command sending module, configured to send a handover command to a UE, and carry its own deployment information in the handover command.

Another UE provided by the embodiment of the present invention includes: a handover weight determination module, configured to determine the weight of this handover according to its own handover auxiliary information; a handover counting module, used to perform handover counting according to the handover weight, and obtain an updated handover times; and a trigger time adjustment module, configured to adjust the trigger time TTT according to the updated switching times.

Another UE provided by the embodiment of the present invention includes: an initialization module, used to preset the initial value TTT ₀ of the trigger time TTT; a threshold setting module, used to preset n thresholds thr ₁ , thr ₂ ,..., thr _n and The n coefficients factor ₁ , factor ₂ , ..., factor _n corresponding to these n thresholds satisfy 0<thre1<thre2<...<thren and factor ₁ >factor ₂ >...>factor _n >0; where n is a natural number ; The handover counting module is used for handover counting, and every time a handover occurs, the handover counter value HO_count is increased by 1; the threshold adjustment module is used for adjusting the n thresholds or the n coefficients according to its own handover auxiliary information; and triggering For the time adjustment module, if thr _k <HO_count<thre _k+1 is satisfied, TTT=TTT ₀ ×factor _k , where k<n, and k is a natural number; if HO_count>thre _n is satisfied, then TTT=TTT ₀ ×factor _n .

It can be seen from the above embodiments that the above method can adjust TTT according to network deployment information and/or UE handover history information, realize accurate estimation of UE moving speed, and effectively solve the problem of UE moving speed caused by too dense cells in a HetNet network environment. The problem of overestimation and the problem of overestimation of UE moving speed caused by UE switching back and forth at the edge of adjacent cells. Based on the above reasons, the moving speed of the UE can be estimated more accurately through the above method, and a suitable TTT can be adjusted to obtain a suitable TTT, thereby improving handover performance, achieving a lower handover failure rate, and reducing the impact of the ping-pong effect.

Description of drawings

Fig. 1 has shown the flow chart of the method for adjusting TTT described in one embodiment of the present invention;

Fig. 2 has shown the specific implementation method of step 102 in Fig. 1;

FIG. 3 shows a flowchart of a method for adjusting TTT according to another embodiment of the present invention;

Fig. 4 has shown the specific implementation method of step 301 in Fig. 3;

FIG. 5 shows a flowchart of a method for adjusting TTT according to yet another embodiment of the present invention;

FIG. 6 is a schematic diagram of an internal structure of a base station according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of an internal structure of a UE according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of the internal structure of a base station according to another embodiment of the present invention;

FIG. 9 is a schematic diagram of an internal structure of a UE according to another embodiment of the present invention; and

Fig. 10 is a schematic diagram of an internal structure of a UE according to another embodiment of the present invention.

Detailed ways

In order to solve the above problems, the embodiments of the present invention provide a method for adjusting TTT, which can use UE's handover assistance information to realize more accurate mobility state estimation. The UE handover assistance information may include: UE handover history information, source cell and/or target cell deployment information, and the like. Wherein, the deployment information includes one or any combination of information such as cell location, cell size, and cell type.

Various implementations of the present invention will be described in detail below with reference to specific examples and accompanying drawings.

Example 1

Fig. 1 shows a flowchart of a method for adjusting TTT according to an embodiment of the present invention. As shown in Figure 1, the method mainly includes:

Step 101, when a mobile terminal (UE) is handed over, the target base station (TeNB) acquires handover assistance information of the UE;

Step 102, the TeNB determines the handover weight of this handover according to the handover assistance information of the UE;

Step 103, the TeNB sends a handover command to the UE, and carries the above handover weight in the handover command;

Step 104, the UE performs handover counting according to the handover weight in the handover command, and obtains the updated number of handovers; and

Step 105, the UE adjusts the TTT according to the updated handover times.

The specific execution method of each step in Fig. 1 will be further described in detail below in conjunction with the accompanying drawings.

As mentioned above, the handover assistance information may include handover history information of the UE. The handover history information of the UE includes: the list of serving eNBs of the UE after the radio resource control (RRC) connection is established, and the time each eNB serves the UE, etc.

In practical application, the source base station (SeNB) may store the handover history information of the UE, and in the above step 101, the SeNB sends the handover history information of the UE stored by itself to the TeNB after the handover decision. Usually, when the SeNB decides to handover, it will send a handover request message to the TeNB. In this embodiment, while sending the handover request, the SeNB sends the handover history information of the UE to the TeNB, for example, through the X2 interface.

Or, as an alternative to the above solution, other entities in the network other than the SeNB, such as a Mobility Management Entity (MME), may also store the handover history information of the UE, and in the above step 101, after the handover decision, the MME Send the handover history information of the UE stored by itself to the TeNB.

In addition, as mentioned above, the handover assistance information may also include deployment information of the source cell and/or deployment information of the target cell. Usually, after the network deployment is completed, the core network will store the deployment information of each cell, and each eNB can obtain the deployment information of itself and its adjacent cells from the core network at one time.

Specifically, in the above step 102, if the handover assistance information only includes the UE's handover history information, TeNB can determine the first handover weight according to the UE's handover history information, and use the first handover weight as the handover weight of this handover ; If the handover assistance information only includes the deployment information of the target cell, TeNB can determine the second handover weight according to the deployment information of the target cell, and use the second handover weight as the handover weight of this handover; if the handover assistance information includes both UE's The handover history information also includes the deployment information of the target cell, so the handover weight of this handover can be determined according to the method shown in FIG. 2 . The method shown in Figure 2 specifically includes:

Step 1021: The TeNB determines the first handover weight according to the handover history information of the UE;

Step 1022: TeNB determines the second handover weight according to the deployment information of the target cell; and

Step 1023: The TeNB selects the minimum value of the first handover weight and the second handover weight as the handover weight of this handover.

Wherein, the specific method for the TeNB to determine the first handover weight according to the handover history information of the UE is: if it is judged according to the handover history information of the UE that the UE is handed back and forth between adjacent cells, then the first handover weight is set to 0; otherwise , setting the first switch weight to 1. For example, if it is determined according to the handover history information of the UE that within a predetermined period of time, the UE is ready to handover back to cell A after being handed over from cell A, then the first handover weight may be set to 0; otherwise, the first handover weight Set to 1. The aforementioned predetermined period of time may be predetermined by the eNB and the UE, or may be configured by the eNB to the UE through RRC signaling, and its typical value may be, for example, 1 second.

In addition, the method for the TeNB to determine the second handover weight according to the deployment information of the target cell includes: determining the second handover weight according to the size information of the target cell, where the size of the target cell can be characterized by the diameter of the target cell or the transmit power of the TeNB. Specific methods can include the following two:

Method 1, determining the second handover weight according to the preset correspondence between the cell size of the target cell and the second handover weight. Generally, the larger the cell where the TeNB is located, the smaller its corresponding second handover weight.

Table 1 below provides an example of the corresponding relationship between the diameter of the cell where the TeNB is located and the second handover weight. In practical applications, the second handover weight can be directly determined according to the following Table 1. It should be noted that Table 1 only provides an example, and the specific values in the table below can also be adaptively adjusted in practical applications, and as an alternative, the cell diameter parameters in Table 1 below can also be determined by the TeNB transmit power parameter instead.

Cell diameter (m) 0～100 100～200 200～300 300～400 400 or more Second Toggle Weight 0.2 0.4 0.6 0.8 1

Table 1

Method 2, calculating the second handover weight according to the following formula (1). It should be noted that if the second switching weight calculated according to the following formula (1) is greater than 1, then the second switching weight is set to 1.

ω2=cell_size×γ(1)

Wherein, ω2 represents the second handover weight; cell_size represents the size of the target cell, which can be specifically characterized by the diameter of the target cell or the transmit power of the TeNB; γ is a preset coefficient, such as 0.002.

If the handover assistance information further includes the deployment information of the source cell, in step 102, the second handover weight may be further updated according to the deployment information of the source cell. The specific method includes: judging according to the deployment information of the source cell and the deployment information of the target cell Whether the coverage of the source cell and the target cell are the same or whether the coverage of the source cell is judged to be within the coverage of the target cell, if yes, further setting the second handover weight to 0.

In the above step 103, in order to carry the switching weight in the switching command, a new information element (Information Element, IE) needs to be added in the switching command to carry the switching weight.

In the above step 104, the UE will count handovers according to the following formula (2), and update the number of handovers.

Among them, HO_count represents the number of handovers recorded by the UE; Represents the switch weight of this switch.

It should be noted that, in this embodiment, the above-mentioned counter for counting handovers counts the weighted number of handovers within a predetermined time configured by the system. And, every time the predetermined time passes, the counter will be cleared.

In the above step 105, the UE may adjust the TTT according to the updated number of handovers. Specific methods include:

Method 1: Preset the initial value of TTT TTT ₀ , n thresholds thre ₁ , thre ₂ , ..., thre _n and n coefficients factor ₁ , factor ₂ , ..., factor _n corresponding to these n thresholds, satisfying 0< thre ₁ <thre ₂ <...<thre _n and 1>factor ₁ >factor ₂ >...>factor _n >0, wherein, n is a natural number. If HO_count is greater than the kth threshold and smaller than the k+1th threshold, that is, if thre _k <HO_count<thre _k+1 is satisfied, TTT=TTT ₀ ×factor _k , where k<n, and k is a natural number; and if HO_count>thre _n is satisfied, then let TTT=TTT ₀ ×factor _n .

In one example of the invention, n may be equal to two. That is, if HO_count is greater than a preset first threshold thre ₁ and smaller than a preset second threshold thre ₂ , the UE is considered to be a medium-speed device, and TTT=TTT ₀ ×factor ₁ ; if HO_count is greater than the second threshold thre ₂ , the UE is considered to be a high-speed device, and TTT=TTT ₀ ×factor ₂ . Among them, factor ₁ >factor ₂ .

Method 2: Calculate TTT directly according to the following formula (3), but the condition TTT≤TTT ₀ needs to be met:

$\mathrm{<span\; class="notranslate">\; TTT</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&delta;</span>}}{\mathrm{<span\; class="notranslate">\; HO</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; count</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Wherein, δ is a preset coefficient greater than 0, and δ can be configured through RRC signaling.

The dynamic adjustment of the TTT can be realized through the above two methods, and the smaller TTT can be obtained when the HO_count is larger.

Afterwards, in the next handover process, the UE can apply the dynamically adjusted TTT to trigger measurement reporting.

Example 2:

Fig. 3 shows a method for adjusting TTT according to another embodiment of the present invention. As shown in Figure 3, the method mainly includes:

In step 301, the UE determines the weight of this handover according to its own handover assistance information.

In step 302, the UE performs handover counting according to the handover weight to obtain the updated number of handovers. Wherein, the execution method of step 302 is the same as that of step 104 in the above-mentioned embodiment 1, and will not be repeated here.

In step 303, the UE adjusts the TTT according to the updated handover times. Wherein, the execution method of step 303 is also the same as that of step 105 in the above-mentioned embodiment 1, and will not be repeated here.

The execution method of step 301 in FIG. 4 will be further described in detail below in conjunction with the accompanying drawings.

As mentioned above, the handover assistance information of the UE may include the handover history information of the UE. And in this embodiment, the UE may store its own handover history information.

In addition, the handover assistance information may also include the deployment information of the target cell provided by the TeNB. In this embodiment, the TeNB sends the deployment information of the target cell to the UE through a handover command sent to the UE. The UE extracts the deployment information of the target cell from the received handover command. In this step, in order to carry the deployment information of the target cell in the handover command, a new IE needs to be added in the handover command to carry the deployment information of the target cell.

Specifically, in the above step 301, if the handover assistance information only includes the handover history information of the UE, the UE determines the first handover weight according to the handover history information of the UE, and uses the first handover weight as the handover weight of the current handover. If the handover assistance information only includes the deployment information of the target cell, the UE may determine the second handover weight according to the deployment information of the target cell, and use the second handover weight as the handover weight of the current handover. If the handover assistance information includes both the handover history information of the UE and the deployment information of the target cell, the handover weight of this handover can be determined according to the method shown in FIG. 4 . The methods shown in Figure 4 include:

Step 3011: UE determines the first handover weight according to its own stored handover history information;

Step 3012: UE determines the second handover weight according to the deployment information of the target cell; and

Step 3013: Select the minimum value of the first switching weight and the second switching weight as the switching weight of the current switching.

Wherein, the execution method of step 3011 is the same as that of step 1021, and will not be repeated here.

The execution method of step 3012 is also similar to that of step 1022 . Specifically, in step 3012, the second handover weight may be determined according to the cell size information of the TeNB (for example, the diameter of the target cell or the transmit power of the TeNB), and the specific methods may include the following two:

Method 1, determining the second handover weight according to the predetermined correspondence between the size of the target cell and the second handover weight. Usually, the larger the target cell, the smaller the corresponding second handover weight. For the corresponding relationship between the diameter of the target cell and the second handover weight, reference may be made to Table 1 above.

Method 2: Calculate the second switching weight according to the above formula (1), if the second switching weight calculated according to the formula (1) is greater than 1, set the second switching weight to 1.

In addition, if the handover assistance information further includes the deployment information of the source cell, in step 301, the second handover weight may be further updated according to the deployment information of the source cell. The specific method includes: according to the deployment information of the source cell and the deployment information of the target cell The information determines whether the coverage of the source cell and the target cell are the same or whether the coverage of the source cell is within the coverage of the target cell, and if so, further sets the second handover weight to 0.

Afterwards, in the next handover process, the UE can apply the dynamically adjusted TTT to trigger measurement reporting.

It can be seen from the above embodiments that, on the one hand, the above method can fully consider the handover history information of the UE when counting the number of handovers. If the UE repeatedly handovers to the same cell within a period of time, these handovers will not be counted , so as to effectively solve the problem of overestimation of the UE's moving speed caused when the UE moves back and forth at the edge of the cell; on the other hand, the above method can also fully consider the deployment information of the source cell and the target cell when counting the number of handovers, Therefore, accurate estimation of the UE's moving speed can be realized in the HetNet network environment, and the problem of overestimating the UE's moving speed caused by too dense cells in the HetNet network environment can be effectively solved. Based on the above reasons, the moving speed of the UE can be estimated more accurately through the above method, and a suitable TTT can be adjusted to obtain a suitable TTT, thereby improving handover performance, achieving a lower handover failure rate, and reducing the impact of the ping-pong effect.

Furthermore, in the above method, in order to estimate the mobility state more accurately, the system may further consider the average inter-site distance (InterSite Distance, ISD) or network density when setting the initial value of TTT TTT ₀ . For example, set a lower initial value of TTT TTT ₀ when the average station spacing is small or the network density is high, and set a higher initial value of TTT when the average station spacing is large or the network density is low TTT ₀ .

Example 3

Fig. 5 shows a method for adjusting TTT according to another embodiment of the present invention. As shown in Figure 5, the method mainly includes:

Step 501: Preset an initial value TTT ₀ of TTT.

As mentioned above, when the system sets the initial value of TTT TTT ₀ , the system may further consider the average station distance or network density. For example, set a lower initial value of TTT TTT ₀ when the average station spacing is small or the network density is high, and set a higher initial value of TTT when the average station spacing is large or the network density is low TTT ₀ .

Step 502: Preset n thresholds thre ₁ , thre ₂ ,..., _thren and n coefficients factor ₁ , factor ₂ ,..., factor _n corresponding to these n thresholds, satisfying 0<thre1<thre2<...<thren And 1>factor ₁ >factor ₂ >…>factor _n >0; wherein, n is a natural number.

Step 503: UE performs handover counting, and every time a handover occurs, the handover counter value HO_count is incremented by 1.

Step 504: The UE adjusts the above n thresholds or the above n coefficients according to the handover assistance information;

In this step, the UE may adjust the above n thresholds according to the network deployment information in the handover assistance information, such as network density information or average station distance, so that the greater the network density or the smaller the average station distance, the higher the value of the n thresholds. big. Alternatively, the UE may also adjust the above n thresholds according to the historical handover information of the UE in the handover assistance information. After the UE is handed over from the cell A and prepares to switch back to the cell A again), the values of the above n thresholds are increased, for example, by 1.

As an alternative to the above solution, in this step, the UE can also adjust the above n coefficients according to the network deployment information in the handover assistance information, such as network density information or average station distance, so that the greater the network density or the closer the average station distance The smaller the value of the n coefficients, the larger the value. Alternatively, the UE may also adjust the above n thresholds according to the historical handover information of the UE in the handover assistance information. After the UE is handed over from the cell A and prepares to switch back to the cell A again), the values of the above n coefficients are increased.

Step 505: If HO_count is greater than the kth threshold and smaller than the k+1th threshold, that is, if thr _k <HO_count<thre _k+1 is satisfied, then let TTT=TTT ₀ ×factor _k , where k< n, and k is a natural number; and if HO_count>thre _n is satisfied, then set TTT=TTT ₀ ×factor _n .

It can be seen from the above embodiments that the above method can also adjust the TTT according to the network deployment information and/or the UE handover history information, so that when the network density is high, the distance between stations is small, or the UE switches back and forth between adjacent cells, the TTT can be reduced. Reduce the speed of TTT to realize accurate estimation of UE mobile speed, effectively solve the problem of overestimation of UE mobile speed caused by too dense cells in the HetNet network environment and UE movement caused by UE switching back and forth at the edge of adjacent cells Speed is overestimated, leading to issues with TTT being turned down too quickly. Based on the above reasons, the moving speed of the UE can be estimated more accurately through the above method, and a suitable TTT can be adjusted to obtain a suitable TTT, thereby improving handover performance, achieving a lower handover failure rate, and reducing the impact of the ping-pong effect.

Corresponding to the method in Embodiment 1 above, the embodiment of the present invention also proposes a base station eNB and a user terminal UE for implementing the method.

Figure 6 shows the internal structure of a base station, as shown in Figure 6, the base station includes:

A handover assistance information acquisition module 601, configured to acquire handover assistance information of the UE;

A handover weight determination module 602, configured to determine the handover weight of this handover according to the handover assistance information of the UE;

The handover command issuing module 603 is configured to issue a handover command to the UE, and carry the handover weight in the handover command.

Wherein, the handover assistance information acquisition module 601 may receive the handover history information of the UE from the SeNB or other entities in the network that store the handover history information of the UE, for example, MME.

The handover assistance information obtaining module 601 may also obtain the deployment information of the source cell and/or the deployment information of the target cell according to the method in step 101 .

The handover weight determination module 602 may determine the handover weight of this handover according to the handover auxiliary information according to the method in step 102 .

The handover command sending module 603 may carry the handover weight in the handover command, and send the handover command carrying the handover weight to the UE.

Figure 7 shows the internal structure of a user terminal, as shown in Figure 7, the user terminal includes:

A switching weight receiving module 701, configured to extract the switching weight from the received switching command;

A handover counting module 702, configured to perform handover counting according to the handover weight carried in the handover command, to obtain an updated number of handovers; and

The trigger time adjustment module 703 is configured to adjust the TTT according to the updated switching times.

Wherein, the above switching counting module can perform switching counting according to the method in step 104, and the above triggering time adjusting module can adjust TTT according to the method in step 105 in FIG. 1 , so details are not repeated here.

Corresponding to the method in the above-mentioned embodiment 2, the embodiment of the present invention also proposes a base station eNB and a user terminal UE for realizing the method.

Figure 8 shows the internal structure of a base station, as shown in Figure 8, the base station includes:

The handover command issuing module 801 is configured to issue a handover command to the UE, and carry its own deployment information in the handover command.

Figure 9 shows the internal structure of a user terminal, as shown in Figure 9, the user terminal includes:

A handover weight determination module 901, configured to determine the weight of this handover according to its own handover auxiliary information;

A handover counting module 902, configured to perform handover counting according to the handover weight to obtain an updated number of handovers; and

The trigger time adjustment module 903 is configured to adjust TTT according to the updated switching times.

Wherein, the above-mentioned switching weight determination module 901 can determine the weight of this switching according to step 301; the above-mentioned switching counting module 902 can perform switching counting according to the method of step 302; the above-mentioned trigger time adjustment module 903 can adjust TTT according to the method of step 303, so I won't repeat them here.

Corresponding to the method in Embodiment 3 above, the embodiment of the present invention also proposes a user terminal UE implementing the method.

Figure 10 shows the internal structure of a user terminal, as shown in Figure 10, the user terminal includes:

Initialization module 1001, for presetting the initial value TTT ₀ of TTT;

Threshold setting module 1002, used to pre-set n thresholds thre ₁ , thre ₂ , ..., thre _n and n coefficients factor ₁ , factor ₂ , ..., factor _n corresponding to the n thresholds, satisfying 0<thre1<thre2 <…<thren and 1>factor ₁ >factor ₂ >…>factor _n >0; among them, n is a natural number;

Handover counting module 1003, used for handover counting, every time a handover occurs, the handover counter value HO_count is increased by 1;

An adjustment module 1004, configured to adjust the above n thresholds or the above n coefficients according to the handover assistance information; and

The trigger time adjustment module 1005, if HO_count is greater than the kth threshold and smaller than the k+1th threshold, that is, if thr _k <HO_count<thre _k+1 is satisfied, TTT=TTT ₀ ×factor _k , Where k<n, and k is a natural number; and if HO_count>thre _n is satisfied, TTT=TTT ₀ ×factor _n .

For the specific operations of each module, reference may be made to each step in FIG. 5 , which will not be repeated here.

As mentioned above, the method and device of the present invention can adjust TTT more accurately, so as to achieve better handover performance.

It should be noted that although the method described in the embodiment of the present invention can obtain better results when applied in HetNet, the above method is not limited to be applied in HetNet, and can also be applied in traditional HomoNet.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the present invention. within the scope of protection.

Claims (26)

1. A method for adjusting the trigger time TTT, characterized in that, comprising: When the mobile terminal UE is handed over, the target base station TeNB acquires handover assistance information of the UE; The TeNB determines the handover weight of this handover according to the handover assistance information of the UE; and The TeNB issues a handover command to the UE, and carries the handover weight in the handover command. 2. The method according to claim 1, wherein the UE handover assistance information includes handover history information of the UE. 3. The method according to claim 2, further comprising: the source base station SeNB stores the handover history information of the UE, and sends the handover history information of the UE stored by itself to the TeNB after the handover decision is made. 4. The method according to claim 2, further comprising: the mobility management entity (MME) stores the handover history information of the UE, and sends the handover history information of the UE stored by itself to TeNB. 5. The method according to claim 2, wherein the determination by the TeNB of the handover weight of this handover according to the handover assistance information of the UE comprises: determining the first handover weight according to the handover history information of the UE, and determining The first switching weight of is used as the switching weight of this switching. 6. The method according to claim 1, wherein the auxiliary information for UE handover includes deployment information of a target cell; Determining the handover weight of the current handover by the TeNB according to the handover assistance information of the UE includes: determining a second handover weight according to the deployment information of the target cell, and using the determined second handover weight as the handover weight of the current handover. 7. The method according to claim 1, wherein the UE handover assistance information includes handover history information of the UE and deployment information of a target cell; The determination of the handover weight of this handover by the TeNB according to the handover assistance information of the UE includes: determining a first handover weight according to handover history information of the UE; determining a second handover weight according to deployment information of the target cell; and A minimum value among the first switching weight and the second switching weight is selected as the switching weight of this switching. 8. The method according to claim 5 or 7, wherein determining the first handover weight according to the handover history information of the UE comprises: if it is determined according to the handover history information of the UE that within a predetermined period of time, After the UE is handed over from the cell A and prepares to switch back to the cell A again, the first handover weight is set to 0; otherwise, the first handover weight is set to 1. 9. The method according to claim 6 or 7, wherein determining the second handover weight according to deployment information of the target cell comprises: determining the second handover weight according to size information of the target cell. 10. The method according to claim 6 or 7, wherein the handover assistance information of the UE further includes deployment information of the source cell; The method further includes: judging whether the coverage of the source cell and the target cell are the same according to the deployment information of the source cell and the deployment information of the target cell, or judging whether the coverage of the source cell is within the coverage of the target cell, and if so, then Set the second toggle weight to 0. 11. A method for adjusting the trigger time TTT, comprising: The UE performs handover counting according to the handover weight carried in the handover command to obtain an updated number of handovers; and The UE adjusts the TTT according to the updated handover times. 12. The method according to claim 11, wherein the UE performing handover counting according to the handover weight in the handover command comprises: UE performing handover counting according to the following formula: Among them, HO_count represents the number of handovers recorded by the UE; Represents the switching weight carried in the switching command. 13. A method for adjusting the trigger time TTT, comprising: The UE determines the weight of this handover according to its own handover assistance information; The UE performs handover counting according to the handover weight to obtain the updated number of handovers; and The UE adjusts the TTT according to the updated handover times. 14. The method according to claim 13, wherein the handover assistance information includes handover history information stored by the UE itself; The UE determining the handover weight of the current handover according to its own handover assistance information includes: the UE determining a first handover weight according to its own stored handover history information, and using the determined first handover weight as the handover weight of the current handover. 15. The method according to claim 13, wherein the handover assistance information includes deployment information of the target cell; The UE determining the handover weight of this handover according to its own handover assistance information includes: the UE determining a second handover weight according to TeNB deployment information, and using the determined second handover weight as the handover weight of this handover. 16. The method according to claim 13, wherein the handover assistance information includes UE handover history information and target cell deployment information provided by the target base station TeNB; The UE determining the weight of this handover according to its own handover assistance information includes: The UE determines the first handover weight according to handover history information stored by itself; The UE determines the second handover weight according to the deployment information of the target cell provided by the TeNB; and A minimum value among the first switching weight and the second switching weight is selected as the switching weight of the current switching. 17. The method according to claim 14 or 16, wherein determining the first handover weight according to handover history information stored by the UE comprises: If it is judged according to the handover history information of the UE that within a predetermined period of time, the UE is ready to handover back to cell A after being handed over from cell A, then set the first handover weight to 0; otherwise, set the first handover weight to 0. The weight is set to 1. 18. The method according to claim 15 or 16, wherein the UE determining the second handover weight according to the deployment information of the target cell comprises: determining the second handover weight according to the size information of the target cell. 19. The method according to claim 15 or 16, wherein the handover assistance information of the UE further includes deployment information of a source cell; The method further includes: judging whether the coverage of the source cell and the target cell are the same according to the deployment information of the source cell and the deployment information of the target cell, or judging whether the coverage of the source cell is within the coverage of the target cell, and if so, then Set the second toggle weight to 0. 20. The method according to claim 13, wherein the UE performing handover counting according to the handover weight comprises: UE performing handover counting according to the following formula: Among them, HO_count represents the number of handovers recorded by the UE; Represents the switch weight of this switch. 21. A method for adjusting the trigger time TTT, comprising: Preset the initial value TTT ₀ of TTT; Preset n thresholds thre ₁ , thre ₂ ,..., _thren and n coefficients factor ₁ , factor ₂ ,..., factor _n corresponding to the n thresholds, satisfying 0<thre1<thre2<...<thren and 1 >factor ₁ >factor ₂ >…>factor _n >0; where, n is a natural number; The UE performs handover counting, and every time a handover occurs, the handover counter value HO_count is increased by 1; The UE adjusts the n thresholds or the n coefficients according to the handover assistance information of the UE; If thre _k <HO_count<thre _k+1 is satisfied, TTT=TTT ₀ ×factor _k , where k<n, and k is a natural number; If HO_count>thre _n is satisfied, then set TTT=TTT ₀ ×factor _n . 22. A base station, comprising: A handover auxiliary information acquisition module, configured to acquire handover auxiliary information of the user terminal UE; A handover weight determination module, configured to determine the handover weight of this handover according to the handover assistance information of the UE; and The handover command issuing module is configured to issue a handover command to the UE, and carry the handover weight in the handover command. 23. A user terminal UE, characterized in that it comprises: A switch weight receiving module is used to extract the switch weight from the received switch command; A switching counting module, configured to perform switching counting according to the switching weight in the switching command to obtain the updated number of switching times; and The trigger time adjustment module is configured to adjust the trigger time TTT according to the updated switching times. 24. A base station, comprising: The handover command issuing module is configured to issue a handover command to the UE, and carry its own deployment information in the handover command. 25. A user terminal UE, characterized in that it comprises: A handover weight determination module, configured to determine the weight of this handover according to its own handover auxiliary information; A handover counting module, configured to perform handover counting according to handover weights to obtain an updated number of handovers; and The trigger time adjustment module is configured to adjust the trigger time TTT according to the updated switching times. 26. A user terminal UE, characterized in that it comprises: The initialization module is used to pre-set the initial value TTT ₀ of the trigger time TTT; The threshold setting module is used to pre-set n thresholds thre ₁ , thre ₂ , ..., thre _n and n coefficients factor ₁ , factor ₂ , ..., factor _n corresponding to the n thresholds, satisfying 0<thre1<thre2<…<thren and factor ₁ >factor ₂ >…>factor _n >0; among them, n is a natural number; The handover counting module is used for handover counting, and every time a handover occurs, the handover counter value HO_count is increased by 1; a threshold adjustment module, configured to adjust the n thresholds or the n coefficients according to its own handover assistance information; and Triggering the time adjustment module, if thr _k <HO_count<thre _k+1 is satisfied, TTT=TTT ₀ ×factor _k , where k<n, and k is a natural number; If HO_count>thre _n is satisfied, then set TTT=TTT ₀ ×factor _n .