WO2012155596A1

WO2012155596A1 - Method and device for adjusting mobility parameter in heterogeneous network

Info

Publication number: WO2012155596A1
Application number: PCT/CN2012/071695
Authority: WO
Inventors: 黄亚达
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-08-15
Filing date: 2012-02-28
Publication date: 2012-11-22
Also published as: CN102938911A; CN102938911B

Abstract

A method and device for adjusting mobility parameter in a heterogeneous network are provided by the present invention, which increase a success rate for performing mobility in the heterogeneous network. The method comprises the following steps: an appointed cell is selected by a terminal; according to the selected appointed cell, a traveling speed of the terminal and/or an arrangement density of the cell are evaluated; according to the evaluation result, the mobility parameter is adjusted. The terminal comprises an appointed cell selecting module, an evaluation module and an adjusting module. Wherein, said appointed cell selecting module is used for selecting an appointed cell; said evaluation module is used for evaluating a traveling speed of the terminal and/or an arrangement density of the cell according to the selected appointed cell; and said adjusting module is used for adjusting a mobility parameter, according to the evaluated result. In the invention, through an enhanced mobility state and an evaluation of the arrangement density of network nodes, the method and device adaptively adjust the mobility parameter of the device in the flexible heterogeneous network. Thus, the success rate for performing mobility is increased in the heterogeneous network.

Description

Method and device for adjusting mobility parameter in heterogeneous network

Technical field

The present invention relates to long term evolution technology in a mobile communication system, and in particular, to a heterogeneous network mobility parameter adjustment method and apparatus.

Background technique

Long Term Evolution (LTE) technology allows operators to use new and broader spectrum, with higher data rates, lower latency, and flat IP-based architectures than 3G networks. Since single-wire link performance is approaching the theoretical limit through broadband technology and multi-antenna technology, the performance leap of next-generation wireless networks comes from the enhancement based on network topology. By deploying low-power network cells, such as micro cells, pico cells, and relay nodes, through flexible and low-cost deployment within the macro cell coverage, To supplement the hot spot location of the macro cell or the place where the network coverage is missing.

Originally, only the network in which the macro cell is deployed is called a homogeneous network, that is, a network composed of cells with the same or similar characteristics and properties. The current homogeneous network deployment is centered on the macro cell, and all macro base stations have similarities. Transmit power, antenna mode, receiver noise, and similar backhaul connections to the network. In addition, all base stations can provide similar quality of service (QoS) to all terminals, and each macro cell can serve approximately the same number of user terminals. The location of the macro base station is carefully selected through network planning, and the base station needs to be properly configured to maximize interference between coverage and control base stations. However, this deployment process is complex and iterative. In addition, it has become increasingly difficult to deploy macro base stations in densely populated urban areas.

Wireless cellular systems have evolved over the decades and, in the case of single-base station deployments, system throughput is close to the theoretically optimal performance of the channel. Therefore, the further evolution of the wireless network will improve the performance of the system by increasing the distance between the base station and the terminal through a more diverse network topology to improve the frequency efficiency per unit area. As shown in FIG. 1, in the macro cell, a low-power pico cell is deployed in a hotspot area in the user set. Although the power of the pico cell is relatively low, the distance between it and the user is relatively close, so that the user can obtain better quality of service through the pico cell than the macro cell. Careful network planning is required relative to homogeneous networks, and low-power cell-passing in heterogeneous networks Often no strict planning is required, and due to the large number of pico communities, network planning is not possible. In addition, the low-power nodes are lightweight and the site deployment is flexible: densely populated areas such as streetsides, corridors, and coffee shops can easily deploy low-power nodes to compensate for coverage holes in macro cells or for diverting macro cells. Partial load in the hot spot area.

When the terminals are at different moving speeds, the speed requirements for switching are also different. For the high-speed mobile terminals in the same environment, it is necessary to complete the switching more quickly than the low-speed mobile terminals. In the case where the general terminal is not equipped with a speed sensor, it is difficult to evaluate its own speed, and the speed of the terminal also changes. In order to meet the switching performance of the terminal at different speeds, a cellular isomorphic network system is commonly used. A method for evaluating terminal mobility state is described as follows, taking the LTE system terminal idle (IDLE) state as an example:

During the T _CRmax time, if the number of cell _reselection times of the terminal is greater than N _CR — M and less than N _CR — H , the terminal satisfies the medium speed condition, and the mobile state of the terminal is considered to be medium speed;

During the T _CRmax time, the number of cell _reselection times of the terminal is greater than N _CR — H , then the terminal satisfies the high speed condition, and the mobile state of the terminal is considered to be high speed;

During the T _CRmaxHyst time, if the terminal does not satisfy the medium speed condition or the high speed condition, the terminal satisfies the low speed condition, and the mobile state of the terminal is considered to be low speed.

Where T _CRmax is the statistical time of the number of cell reselection times, N _CR — M is the number of cell reselection times of the medium speed condition, N _CR — H is the number of cell reselection times of the high speed condition, and T _CRmaxHyst is the statistical time of the low speed condition.

When the target cell measurement is better than the serving cell measurement within the reselection timer (Trselection) time by a threshold area reselection hysteresis parameter (Qhyst) threshold, the terminal performs cell reselection. Obviously, the larger Treselection and Qhyst, the slower the terminal reselection, and vice versa.

The network is configured with a Speed dependent Scaling Factor for Treselection and a Delay dependent Delay Factor for the medium and high speed states, respectively.

When the terminal is at medium and high speeds, Treselection and Qhyst will be multiplied by the corresponding ratio factor (since Qhyst is in dB units, so the actual operation is added) to speed up the terminal reselection.

This kind of evaluation of the movement speed of the terminal by counting the changes of the serving cell, thereby dynamically repairing The method of changing the mobility parameters to suit its speed of motion is widely used in the mobile functions of various homogeneous cellular networks.

In a heterogeneous network, due to the non-uniform deployment of low-power cells, even at the same speed, when the terminal is deployed in a low power node centralized deployment area, the number of reselection times will be increased, and it will be judged as a high-speed terminal. In the low power node distributed deployment area, it is judged as a low speed terminal, so that the problem of the mobile state judgment error occurs. The existing switch configuration cannot adapt to the flexible network deployment of heterogeneous networks. Summary of the invention

The technical problem to be solved by the present invention is to provide a method and device for adjusting mobility parameters in a heterogeneous network, which improves the success rate of mobile execution in a heterogeneous network.

To solve the above technical problem, the present invention provides a method for adjusting mobility parameters in a heterogeneous network, including:

The terminal selects a designated cell;

Evaluating the moving speed of the terminal and/or the deployment density of the designated cell according to the selected designated cell;

Adjust the mobility parameters based on the evaluation results.

The above method can also have the following characteristics:

The step of evaluating the moving speed of the terminal according to the selected designated cell includes: determining, according to the number of times of change between the designated cells in the first predetermined time of the serving cell of the terminal, the mobile state of the terminal.

The above method can also have the following characteristics:

The step of the terminal selecting a designated cell includes:

Selecting a designated cell according to the specified cell list information delivered by the network side; or

Determining the designated cell according to the specified cell flag information sent by the network side; or

The designated cell is determined according to the serving cell change interval of the terminal.

The above method can also have the following characteristics:

The step of determining the designated cell according to the serving cell change interval time includes: The time interval in which the serving cell of the terminal changes from the first cell to the second cell is greater than a predetermined time threshold, and then determines that the first cell and the second cell are designated cells.

The above method can also have the following characteristics:

The step of evaluating the deployment density of the designated cell according to the selected designated cell includes: evaluating, according to the number of times of change between the designated cells, the serving cell of the terminal in a second predetermined time; or

Evaluating the deployment density of the designated cell according to an interval at which the serving cell of the terminal changes between the designated cells; or

The deployment density factor of the designated cell is calculated according to a ratio of an interval between the serving cell of the terminal and the reference time.

The above method can also have the following characteristics:

The step of evaluating the deployment density of the designated cell according to the number of changes between the designated cells according to the serving cell of the terminal in the second predetermined time includes:

Determining, in a fourth specified time, that the number of times the serving cell of the terminal changes between the designated cells exceeds a fourth threshold, and determining that the specified cell deployment density state is a high density;

And determining, in a fifth specified time, that the number of times the serving cell of the terminal changes between the designated cells exceeds a fifth threshold, and is less than a fourth threshold, and determines that the specified cell deployment density state is a medium density;

And determining, in the sixth specified time, that the number of times that the serving cell of the terminal changes between the designated cells is less than a fifth threshold, determining that the specified cell deployment density state is a low density.

The above method can also have the following characteristics:

The step of evaluating the deployment density of the designated cell according to the interval at which the serving cell of the terminal changes between the designated cells includes:

And determining, by the serving cell of the terminal, that the interval between the specified cells is smaller than the fourth specified time, determining that the specified cell deployment density state is a high density;

The interval at which the serving cell of the terminal changes between the designated cells is less than the fifth specified time, but is not less than the fourth specified time, determining that the specified cell deployment density state is medium density; the serving cell of the terminal is The interval between the specified cell changes is greater than the fifth specified time Therefore, it is determined that the specified cell deployment density state is a low density.

The above method can also have the following characteristics:

The step of calculating the deployment density factor of the cell according to the ratio of the interval between the changed time of the serving cell of the terminal and the reference time of the serving cell includes:

部署 Calculate the deployment density factor A by using the following formula: A=Ceiling(Tl/Ts), where Ceiling is rounded up, T1 is the interval between serving cells changing between the specified cells, and Ts is the interval between serving cell changes. Reference value.

The above method can also have the following characteristics:

The steps of determining the designated cell according to the serving cell change interval include:

If the time interval of the serving cell of the terminal changing from the first cell to the second cell is less than a predetermined time threshold, determining that the second cell is the designated cell.

The above method can also have the following characteristics:

According to the evaluation result, the step of adjusting the mobility parameter includes:

Determining a first mobility parameter that needs to be adjusted according to the estimated moving speed state of the terminal, and adjusting an adjustment factor of the mobility parameter;

Determining, according to the deployed density of the evaluated cell, a second mobility parameter that needs to be adjusted, and using a deployment density factor corresponding to the deployed density of the evaluated cell as an adjustment factor for adjusting the mobility parameter that needs to be adjusted;

When the first mobility parameter and the second mobility parameter that need to be adjusted are the same, the factor obtained by weighting the moving speed state factor and the deployment density factor is used as an adjustment factor for adjusting the mobility parameter.

The present invention also provides a heterogeneous intra-network mobility parameter adjustment terminal, which includes a designated cell selection module, an evaluation module, and an adjustment module, where:

The designated cell selection module is configured to: select a designated cell;

The evaluation module is configured to: determine a moving speed of the terminal and/or a deployment density of the designated cell according to the selected designated cell; The adjustment module is configured to: adjust the mobility parameter according to the evaluation result.

The above terminal can also have the following characteristics:

The evaluation module is configured to: determine, according to the selected designated cell, the moving speed of the terminal according to the following manner: determining, according to the number of changes between the designated cells, the serving cell of the terminal in the first predetermined time The state of movement.

The above terminal can also have the following characteristics:

The specified cell selection module is configured to select a designated cell by using any one of the following methods: selecting a designated cell according to the specified cell list information sent by the network side;

Determining a designated cell according to the specified cell flag information sent by the network side;

The above terminal can also have the following characteristics:

The designated cell selection module is configured to determine the designated cell according to the serving cell change interval time in the following manner:

And determining that the time interval of the serving cell of the terminal from the first cell to the second cell is greater than a predetermined time threshold, determining that the first cell and the second cell are designated cells.

The above terminal can also have the following characteristics:

The evaluation module is configured to evaluate the deployment density of the designated cell according to the selected designated cell in the following manner:

Determining, according to the number of changes between the designated cells, the deployment density of the designated cell according to the serving cell of the terminal within a second predetermined time; or

Determining, according to the serving cell change interval of the serving cell of the terminal, the deployment density of the designated cell; or

The deployment density factor of the designated cell is calculated according to a ratio of a serving cell change interval between the designated cells of the terminal to the reference time.

The above terminal can also have the following characteristics:

The evaluation module is configured to determine the deployment density of the cell according to the number of changes of the serving cell of the terminal in the second predetermined time and between the designated cells in the following manner: The number of times that the serving cell of the terminal changes between the designated cells exceeds the fourth threshold, and determines that the specified cell deployment density state is high density;

In the fifth specified time, the number of times that the serving cell of the terminal changes between the designated cells exceeds the fifth threshold, and is less than the fourth threshold, and determines that the specified cell deployment density state is medium density;

In the sixth specified time, if the number of times the serving cell of the terminal changes between the designated cells is less than the fifth threshold, it is determined that the specified cell deployment density state is a low density.

The above terminal can also have the following characteristics:

The evaluation module is configured to determine the deployment density of the designated cell according to a change interval of the serving cell of the terminal between the designated cells in the following manner:

And determining, by the serving cell of the terminal, that the interval between the change of the designated cell is less than the fourth specified time, determining that the specified cell deployment density state is a high density;

The interval at which the serving cell of the terminal changes between the designated cells is less than the fifth specified time, but is not less than the fourth specified time, and then determines that the specified cell deployment density state is medium density; the interval at which the serving cell of the terminal changes between the designated cells If the time is greater than the fifth specified time, it is determined that the specified cell deployment density state is a low density.

The above terminal can also have the following characteristics:

The evaluation module is configured to calculate a deployment density factor of the cell according to a ratio of a change interval between the designated cell and the reference time of the serving cell of the terminal in the following manner:

部署 Calculate the deployment density factor A by using the following formula: A=Ceiling(Tl/Ts), where Ceiling is rounded up, T1 is the interval between serving cells changing between designated cells, and Ts is the interval time reference value of the serving cell change. .

The above terminal can also have the following characteristics:

The above terminal can also have the following characteristics: The adjustment module is set to:

Determining an adjustment factor of the first shifted mobility parameter that needs to be adjusted according to the moving speed state of the terminal evaluated by the evaluation module;

Determining, according to the deployment density of the cell that is evaluated by the evaluation module, a second mobility parameter that needs to be adjusted, and using a deployment density factor corresponding to the deployment density of the cell as an adjustment factor for adjusting the mobility parameter that needs to be adjusted;

According to the network deployment features of the heterogeneous network, the embodiment of the present invention adjusts the mobility parameters of the terminal in the flexible and variable heterogeneous network by using the enhanced mobile state and the evaluation of the deployment density of the network node to improve the heterogeneity. The success rate of mobile execution in the network. BRIEF abstract

Figure 1 is a schematic diagram of a heterogeneous network;

2 is a flow chart of an embodiment of the present invention;

3 is a schematic diagram of a change interval of a serving cell according to Embodiment 1 of the present invention;

4 is a diagram showing usage and effect diagrams of a speed estimation algorithm for deploying a uniform heterogeneous network in Embodiment 1 of the present invention;

5 is a diagram showing usage and effect diagrams of a speed estimation algorithm for a heterogeneous network deployed in an uneven manner according to Embodiment 1 of the present invention;

6 is a schematic diagram of a change interval of a serving cell according to Embodiment 3 of the present invention;

7 is a schematic diagram of a change interval of a serving cell according to Embodiment 3 of the present invention;

FIG. 8 is a schematic structural diagram of a mobility parameter adjustment terminal in a heterogeneous network according to an embodiment of the present invention. Preferred embodiment of the invention

In general, the mobile process includes search and measurement of the target cell, mobility condition determination, and mobile execution. The searching and measuring of the target cell includes that the terminal performs the search or measurement on the target cell according to the condition of the search period or the measurement period; the determination of the mobility condition refers to whether the terminal determines whether the measured cell measurement quantity satisfies a preset condition. When the condition is met, it is considered that a mobility process needs to occur. Taking LTE as an example, when the terminal is in the IDLE state, when the measurement of the target cell is better than the current serving cell, and the condition is satisfied in the Treselection time, the terminal considers that the mobility process in the IDLE state can be initiated, that is, the cell Re-election. When the terminal is in the CONNECT state, the measurement event is usually used for the mobility condition determination, such as when the A3 event is configured, when the measurement amount of the target cell is better than the serving cell measurement amount by an offset (for example, 3 dB), and If the condition is met, the terminal will report the measurement report to the network side. The network side receives the measurement report and determines the process of initiating the handover. After the target side completes the handover preparation, it sends a handover command to the terminal. , the terminal accesses in the target cell, completes the handover, that is, the mobility process under CONNECT.

In a heterogeneous network, the speed of the terminal and the actual heterogeneous network topology all affect the success/failure rate of the mobile execution (such as the handover success/failure rate). Specifically, the faster the terminal moves, the faster the mobile execution process needs to be completed, or the mobile execution process needs to be started earlier. The shorter the distance between network cells, the steeper the cell edge signal drops, the faster the cell edge signal changes, so the terminal also needs to complete the mobile execution process faster or start the mobile execution process earlier. The fast-moving terminal in the heterogeneous network is relatively slow-moving, and the mobile execution failure is mainly caused by the late execution of the mobile. Similarly, for the same terminal, the movement between cells with close spacing is relatively lower than the movement between cells with far spacing. In general, the time of mobile execution is relatively fixed, which is related to the processing delay of the terminal and the network. Usually, some adaptive adjustment is made to the search and measurement of the target cell or the judgment of the mobility condition. To this end, embodiments of the present invention improve the heterogeneous network mobile execution success rate by adjusting the mobility parameters to achieve a faster start or earlier occurrence of the mobile execution process. For example, shortening the search or measurement period (such as Treselection or TimeToTrigger) makes the mobility condition meet the condition in a shorter time, and/or by lowering the mobility condition threshold (such as reselecting the threshold Qhyst or offset), which can make the movement Sexual conditions easily satisfy the trigger condition. Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments in the present application may be arbitrarily combined with each other.

Example 1

This embodiment describes how to select a designated cell participating in the mobile state assessment, and how to evaluate the mobile state of the terminal based on the cells. As shown in Figure 2, it includes:

Step 101: The terminal selects a designated cell that participates in the mobile state assessment.

Specifically, the selected designated cell may be a uniformly deployed cell, for example, one or more of the following cells: a macro cell, a micro cell, and a pico cell. Uniform deployment means that adjacent cell spacing (or station spacing) is essentially the same. You can use the following methods to select a specific cell:

Method 1: Select a corresponding cell as a designated cell according to the specified cell list information sent by the network side or the designated cell flag bit information;

For example, the network side notifies the terminal to specify a cell set by means of broadcast or dedicated signaling, and the designated cell set includes a cell that is uniformly deployed, and the cell is characterized by a feature identifier or a feature range. The terminal may determine whether the current serving cell is a designated cell according to whether the current serving cell is identified in the set. The feature identifier may be, for example, a physical cell identity (PCI) or a cell scrambling code, which may distinguish the identity information of the cell locally or globally. The set may also be a non-designated cell set, that is, the non-uniformly deployed cell, and the terminal determines that the current serving cell is included in the set, and determines that it is a non-uniformly deployed cell, and the terminal does not select the cell as the designated cell, and selects unless uniformly deployed. The other cells (that is, the cells are uniformly deployed) are designated cells.

For example, the network side informs the terminal whether the current serving cell is a uniformly deployed cell through broadcast or dedicated signaling (only applicable to the connected state), and the network side can set a uniformly deployed flag bit for the uniformly deployed cell and/or a non-uniformly deployed cell. Set the flag for non-uniform deployment. The terminal may determine, according to the flag information of the current serving cell, whether the current serving cell is a designated cell. When the network is deployed, the operator can determine whether to send the unmarked deployment flag in the cell according to whether the cell is deployed in a certain manner. For example, the operator deploys a low-power cell in the homogeneous network to form a heterogeneous network. A non-uniform hook deployment flag is broadcast. When the terminal reads the flag when entering the cell, the cell can be considered as a non-uniformly deployed cell, and the cell is not selected as the designated cell. When the terminal selects a cell according to the flag bit, it can determine whether the current serving cell is a designated cell. After a period of time, the terminal can obtain a designated cell list by using the terminal to move between different cells, and the list includes the determined designated cell.

Method 2: The terminal selects a designated cell by using a serving cell change interval.

The serving cell changes from one cell to another, and can be completed by one or several consecutive serving cell change procedures. The terminal can measure the interval of change of the adjacent serving cell every time the serving cell changes process. One cell to another cell may be composed of one or several neighbor cell changes, and the time required for each cell change process may be obtained to obtain the time required for one cell to change to another cell. During the specified time, the speed is considered to be substantially constant or the change is small, so the spacing between two cells is proportional to the time required for one cell to change to another. And determining, according to whether the time interval of the terminal from the first cell to the second cell is greater than a predetermined time threshold, determining whether the first cell and the second cell are selected as the designated cell, and if the threshold is greater than the predetermined threshold, selecting the first cell and the second The cell is a designated cell, and the first cell and the second cell are uniformly deployed cells.

As shown in FIG. 3, the historical movement trajectory of the terminal over a period of time, the arrow indicates the incoming cell, and the time in the box indicates the time the terminal stays in the cell, from entering the cell to leaving the cell. The direction of the time axis from left to right indicates that the terminal first enters celll, and after the T1 time, the serving cell is changed to cell2. After T1, the serving cell is changed to cell3, and then the serving cell is changed to cell9. In this embodiment, the time that the terminal stays in the cell 1 is substantially the same as the time that the terminal stays in the cell 2, so the terminal can determine that the three cells, cell1, cell2, and cell3, are uniformly deployed cells. The time that the terminal stays in cell3 is T2, which is smaller than T1. It can be estimated that the station spacing between cell4 and cell3 is short and is a non-uniformly deployed cell, so cell4 is not selected as the designated cell. However, the terminal _{C ell3} residence time and the residence time of the terminal and is cell4 T2 + T3 - T1, and the distance can be estimated between cell3 to celll cel to cell2, ^^ cell2 to cell3 present between the same, so cel It can be considered as a cell that is evenly deployed. Through this judgment, the interval between the serving cell change between the cell 1 and the cell 2 and the change interval of the serving cell between the cell 2 and the cell 3, the interval of the serving cell change between the cell 3 and the cel, and the service between the cel and the cell 6 can be obtained. The cell change interval, and the serving cell change interval between the cell 6 and the cell 9 are the same, and the cells such as cell1 and cell2 may be referred to as a pair of cells with the same serving cell change interval, and the cell with the same change interval of the serving cell has N ( If N=3), the UE can use the monthly service. The cell change interval (T1) is used as a measurement time of the uniformly deployed cell, and the measured time can be used to determine whether the serving cell is a uniformly deployed cell in a later period of time. When there are multiple serving cell change intervals that can be used as time measurement, as shown in FIG. 3, the serving cell change interval between cell6 and cell7 is the same as the serving cell change interval between cell7 and cell8, and cell8 and cell9. , all are T4. Both T1 and Τ4 satisfy the first condition (the cell logarithm is greater than N), and the terminal can select according to another preset second condition: To measure the time, for example, T1>T4, then choose to use T1 as the measurement time; or select the serving cell change interval that satisfies the same serving cell change interval time cell number in the specified time as the measurement time, for example, satisfying the interval T1. The cell logarithm is 5 (celll and cell2, cell2 and cell3, cell3 and cell5, cell5 and cell6, and cell6 and cell9), and the number of cells satisfying Τ4 is 3 (cell6 and cell7, cell7 and cell8, cell8 and cell9) , so choose Tl as a measure of time. The same in the engineering implementation refers to the equality within the specified error range. For example, if the difference between the two serving cell change intervals is less than a specified value (the value may be configured by the network), the two serving cell change intervals are considered. The time is the same, or the same difference between the two serving cell change intervals is considered to be the same.

Step 102: Estimate the moving speed of the terminal according to the designated cell selected in step 101.

The mobile state of the terminal is determined according to the number of changes of the terminal between the designated cells within the first predetermined time. Specifically, the following conditions can be used to evaluate the moving speed of the terminal:

In the first specified time (T-SH), when the number of times the terminal changes between the designated cells is greater than the first threshold (N-SH), it is determined that the mobile state of the terminal is high speed;

In the second specified time (T_SM), the number of times the terminal changes between the designated cells is greater than the second threshold (N_SM), and is less than the first threshold, determining that the mobile state of the terminal is a medium speed;

In the third specified time (T_SL), the number of times the terminal changes between the designated cells is less than the second threshold (N_SM), that is, the terminal does not satisfy the high speed condition or the medium speed condition, and then determines the movement of the terminal. The status is low speed.

The first, second, and third designated times may all be the same or partially the same or may be completely different. In order to avoid the impact of ping-pong switching or re-selection in the specific calculation of the number of inter-cell changes, two or more consecutive handovers or reselections between the same serving cell, the number of changes between the designated cells is only recorded as one. The number of times of the small interval change is treated as the cell outside the designated cell in the list of serving cells that has entered in the most recent period of time. When the adjacent designated cell is not the same cell, it is counted as a change between the specified cells. For example: When the list of serving cells that the terminal has recently entered is al, bl, a2, b2, a3. Let an is the designated cell, then the list after deleting the non-designated cell is al, a2, a3, and record the number of times the terminal changes between the designated cells is 2 times; when the list of recently visited service cells is al, bl, al , b2, a2, b2, a3, record the number of times the terminal changes between designated cells is 2 times; when the list of recently visited service cells is al, bl, al, a2, al, b2, a3, record The number of times the terminal changes between the designated cells is 2 times, because al, a2, al are ping-pong handovers; when the list of recently visited serving cells is al, bl, a2, b2, al, b3, a3, the terminal is recorded. The number of times of change between the specified cells is 3, because al, bl, a2, b2, al are not ping-pong switches.

Step 103: Adjust a mobility parameter according to the estimated moving speed of the terminal.

Generally, during the moving process, the terminal adjusts the configuration according to the movement state determined in step 102 based on the movement parameters respectively set by the network for each movement state, and automatically adjusts one or more of the following configuration parameters: movement condition determination time, mobility Conditional threshold, measured value L3 filter factor, measurement sample interval (or measurement reporting interval), etc. The motion condition determination time includes an idle state cell reselection time Treselection or a connection state switching event trigger timer TimeToTrigger. The mobility condition threshold includes a reselection threshold Qhyst that affects the reselection of the idle state cell, and affects the connection state handover event to trigger the cell offset Ocn or the event offset offset.

The use and effect of the speed evaluation algorithm of this embodiment are described by the following example. A group of cells is deployed laterally as shown in FIG. 4, a long column with a height of 2 represents a macro cell, and a short column with a height of 1 represents a pico cell. . The density of the macro cell is deployed, that is, the station spacing is equal. A pico cell is deployed in equal density under each macro cell. T=T—SH=T—SM, the dotted line indicates the number of serving cell handovers of the slow terminal within the specified time T, and the solid line indicates the number of serving cell handovers of the fast terminal in T. In this example, the designated cell may be a macro cell, and the terminal may use only the macro cell in the speed estimation. When the speeds are different by one time, the terminal's counting within the specified time is also doubled. Since the pico cell is evenly deployed in the macro in this example, the pico cell and the macro will be Counting the cell at the same time in the speed assessment does not change the result of the speed assessment. As shown in the figure, when the terminal of the speed V arrives from another macro to another macro cell in the T time, the number of serving cell changes of the terminal is lmacro+4 pico=5. The terminal of speed 2v can reach the second macro after a macro through a macro within the same time T. Therefore, the number of serving cell changes of the terminal is 2 macro + 8 pico = 10. It is obvious that the ratio of the results of the speed assessment is in multiples of the actual speed of the terminal. In the case of the pico non-uniform deployment shown in FIG. 5, it is apparent that only the uniformly deployed macro can be used in the speed evaluation and the non-uniformly deployed pico cannot be used.

Example 2

This embodiment describes how to evaluate the cell deployment density based on the designated cell.

Step 201: Select a designated cell that participates in cell deployment density state evaluation.

The designated cell in this step is a non-uniformly deployed cell. For the non-uniform deployment of the cell, refer to the method in the foregoing Embodiment 1, for example: determining the uniformly deployed cell according to the uniformly deployed cell list information sent by the network side or uniformly deploying the cell flag bit information, and selecting a uniform deployment. The other cell is used as the designated cell; or the non-uniformly deployed cell is determined according to the non-uniformly deployed cell list information or the non-uniformly deployed cell flag information sent by the network side, and the non-uniformly deployed cell is selected as the designated cell; or, according to the serving cell change Intervals are used to determine non-uniformly deployed cells. This step can be performed multiple times to select multiple designated cells.

Therefore, when a non-uniform cell is deployed in a uniform cell, it is still considered to be a non-uniform deployment as a whole. Therefore, the designated cell selected in this step may include the designated cell selected in step 101 in Embodiment 1.

As shown in Figure 5, the macro cell is uniformly distributed on the horizontal axis, but the pico cell is deployed unevenly. Some macro cells are surrounded by multiple pico cells, and some pico cells are deployed around the macro cell, or even none. The dotted line indicates the count of the macro cell for the specified terminal within a specified time, and the solid line identifies the count of the pico cell for the designated terminal within the specified time. It can be seen that the ups and downs of the solid line are proportional to the deployment density of the pico cell.

Step 202: Perform an assessment of a cell deployment density state according to the designated cell selected in step 201. The deployment density of the cell is evaluated according to the number of changes of the terminal between the designated cells in the second predetermined time, and the deployment density state of the cell may be evaluated by using the following conditions:

In the fourth specified time (T-DH), the number of times the terminal changes between the designated cells exceeds the fourth threshold (N-DH), and the cell deployment density state is determined to be high density, that is, the inter-station spacing is short;

In the fifth specified time (T-DM), the number of times the terminal changes between the designated cells exceeds the fifth threshold (N-DM), which is less than the fourth threshold, and the cell deployment density state is determined to be medium density, that is, the inter-station spacing is medium;

In the sixth specified time (T-DL), the number of times the terminal changes between the designated cells is less than the fifth threshold (N-DM), that is, if the high-density condition is not satisfied or the medium-density condition is not satisfied, the cell deployment density state is determined. It is low density, that is, the distance between stations is long.

The fourth, fifth, and sixth designated times described above may all be the same or partially the same or may be completely different.

Dividing the cell deployment density state into high density, medium density, and low density is only one implementation manner. In other embodiments, it may also be divided into two states, such as high density and low density, or divided into four states. Can be achieved.

Step 303: Adjust the mobility parameter according to the estimated cell deployment density state to adapt to the moving speed. Similar to step 103, the network may set a corresponding mobility parameter adjustment configuration for different deployment densities. The terminal adjusts the mobility parameters using the corresponding adjustment configuration according to the assessed deployment density.

Example 3

The difference between this embodiment and Embodiment 2 is that the deployment density of the network cell is evaluated using new conditions.

If the serving cell change interval between the designated cells is less than the fourth specified time (T-DH), the cell deployment density state is determined to be high density;

If the serving cell change interval between the designated cells is less than the fifth specified time (T-DM), but not less than the fourth specified time (T-DH), the cell deployment density state is determined to be the medium density;

The serving cell change interval between the designated cells is greater than the fifth specified time (T-DM), that is, the high density condition and the medium density condition are not satisfied, and the cell deployment density state is determined to be a low density. Dividing the cell deployment density state into high density, medium density, and low density is only one implementation manner. In other embodiments, it may also be divided into two states, such as high density and low density, or divided into four states. Can be achieved.

The serving cell change interval is a predefined timing mode. As shown in Figure 6, there are at least the following definitions: It can be T1, that is, the interval from the end of the previous specified cell mobile execution to the end of the subsequent specified cell mobile execution. The time may also be T2, that is, the interval of the previous specified cell mobility condition to trigger the trigger to the next specified cell mobility condition determination trigger, or may be T3, that is, the interval from the entry of a specified cell to the mobility condition determination trigger of the designated cell. The time, or may be T4, that is, the interval time from the start of the mobile execution of the previous designated cell to the mobility condition determination trigger of the next designated cell. Both cell1 and cell2 in Figure 6 are designated cells, and there may be one or more non-designated cells between cell1 and cell2 as shown in Fig. 7, and the definition of timing is unchanged.

The final serving cell change interval may be an average or filtered value of successive serving cell change intervals.

Example 4

The difference between this embodiment and Embodiment 3 is that the deployment density of the network cell is evaluated using new conditions.

And calculating, according to a ratio of a serving cell change interval between the designated cells and a reference time, a deployment density factor of the cell, including:

The deployment density factor A is calculated by the following formula: A=Ceiling(Tl/Ts), where Ceiling is rounded up, T1 is the serving cell change interval between the designated cells, and Ts is the serving cell change interval reference value. In this embodiment, the network may not need to set different corresponding mobile parameter adjustment configurations according to different deployment densities, and the terminal may directly adjust the mobility parameters by using the factors obtained by the foregoing calculation, for example, the TTT adjustment result may be directly used. The above calculated A*TTT. The reference time may be an average value of the serving cell change interval of the specific cell (such as a macro cell) that is explicitly configured by the base station. Example 5

This embodiment describes how to adjust the mobility parameters according to the terminal speed state and the deployment density state.

When the mobility parameter is adjusted together with the deployment speed assessment and the deployment density assessment, the designated cell selected in the deployment density assessment is the complement of the designated cell selected in the speed assessment, that is, the unselected cell in the speed assessment is in the deployment density assessment. Selected cell. For example, if the cell feature identifier of the terminal pico is notified or an identifier is broadcasted in the pico cell to indicate that the cell is pico, the terminal will ignore the cell in the speed assessment, and the cell will be considered in the deployment density assessment.

When adjusting the mobile configuration based on the speed state assessment and the deployment density assessment, the network side pre-configures corresponding adjustment factors such as the time adjustment factor S_T and the threshold adjustment factor S-0 for different mobile states or cell deployment density states, and the terminal The relevant mobility parameters are adjusted by proportional mode (multiplication) or offset mode (addition) according to the current speed state or the deployment density state.

Specifically, determining, according to the evaluated moving speed state of the terminal, an adjustment factor of the mobility parameter to be adjusted for the first mobility to be adjusted; determining, according to the deployed density of the evaluated cell, a second mobility parameter that needs to be adjusted, and evaluating The deployment density factor corresponding to the deployment density of the cell is used as an adjustment factor for adjusting the mobility parameter that needs to be adjusted; when the first mobility parameter and the second mobility parameter that need to be adjusted are the same, the moving speed state factor and the deployment density factor are The factor obtained by weighting the superposition is used as an adjustment factor for adjusting the mobility parameter.

For example, if the medium-speed terminal has a time adjustment factor of S-ST and the threshold adjustment factor is S-SO, the terminal is in the high-density deployment area of the pico, and the corresponding time adjustment factor and threshold adjustment are S_DT and S-DO, the time adjustment factor and threshold adjustment factor after final superposition are (S_ST) ^al *(S— DT) ^bl and a2*S—SO+b2*S—DO, where al, a2, bl and b2 In order to superimpose the weight, the terminal can be notified by pre-configuration or default value, for example, the default is 1.

The embodiment of the present invention further provides a heterogeneous intra-network mobility parameter adjustment terminal, as shown in FIG. 8, including a designated cell selection module, an evaluation module, and an adjustment module, where:

The designated cell selection module is configured to: select a designated cell; The evaluation module is configured to: determine a moving speed of the terminal and/or a deployment density of the designated cell according to the selected designated cell;

The adjustment module is configured to: adjust the mobility parameter according to the evaluation result.

The evaluation module may be configured to: determine, according to the selected designated cell, the moving speed of the terminal according to the following manner: determining, according to the number of changes between the designated cells, the serving cell of the terminal in the first predetermined time The mobile status of the terminal.

The specified cell selection module may be configured to select a designated cell by using any one of the following methods: selecting a designated cell according to the specified cell list information sent by the network side;

The designated cell selection module may be configured to determine the designated cell according to the serving cell change interval time in the following manner:

The evaluation module may be configured to: according to the selected designated cell, evaluate the deployment density of the designated cell in the following manner:

The evaluation module may be configured to determine the deployment density of the cell according to the number of changes of the serving cell of the terminal in the second predetermined time and between the designated cells in the following manner:

In the fourth specified time, the number of times that the serving cell of the terminal changes between the designated cells exceeds the fourth threshold, and determines that the specified cell deployment density state is high density;

During the fifth specified time, the serving cell of the terminal changes more than the number of times between the designated cells. The fifth threshold is less than the fourth threshold, and the determined density of the specified cell is determined to be a medium density. If the number of times the serving cell of the terminal changes between the designated cells is less than the fifth threshold, the specified cell is determined. The deployment density status is low density.

The evaluation module may be configured to determine the deployment density of the designated cell according to a change interval of the serving cell of the terminal in a specified interval in the following manner:

The evaluation module may be configured to calculate a deployment density factor of the cell according to a ratio of a serving cell of the terminal in a specified interval change interval to a reference time in the following manner:

The adjustment module can be configured to:

Determining, according to the deployment density of the cell that is evaluated by the evaluation module, a second mobility parameter that needs to be adjusted, and using a deployment density factor corresponding to the deployment density of the cell as an adjustment factor for adjusting the mobility parameter that needs to be adjusted; When the first mobility parameter and the second mobility parameter that need to be adjusted are the same, the factor obtained by weighting the moving speed state factor and the deployment density factor is used as an adjustment factor for adjusting the mobility parameter.

The various time and number of thresholds described herein can be determined according to the needs of the system or determined by the simulation process.

One of ordinary skill in the art will appreciate that all or a portion of the above steps may be accomplished by a program instructing the associated hardware, such as a read-only memory, a magnetic disk, or an optical disk. Alternatively, all or part of the steps of the above embodiments may also be implemented using one or more integrated circuits. Correspondingly, each module/unit in the above embodiment may be implemented in the form of hardware or in the form of a software function module. The invention is not limited to any specific form of combination of hardware and software.

It is a matter of course that the invention may be embodied in various other forms and modifications without departing from the spirit and scope of the invention.

INDUSTRIAL APPLICABILITY According to the network deployment features of a heterogeneous network, the embodiments of the present invention adjust the mobility parameters of the terminal in a flexible and heterogeneous heterogeneous network by using an enhanced mobile state and an assessment of the deployment density of the network node. Improve the success rate of mobile execution in heterogeneous networks.

Claims

Claim

A method for adjusting mobility parameter in a heterogeneous network, comprising:

The terminal selects a designated cell;

Adjust the mobility parameters based on the evaluation results.

2. The method of claim 1 wherein:

3. The method of claim 2, wherein:

The step of the terminal selecting a designated cell includes:

4. The method of claim 3, wherein:

The step of determining the designated cell according to the serving cell change interval time includes:

The time interval in which the serving cell of the terminal changes from the first cell to the second cell is greater than a predetermined time threshold, and then determines that the first cell and the second cell are designated cells.

5. The method of any of claims 1-4, wherein:

Ratio of the interval between the change of the serving cell of the terminal to the designated cell and the reference time The value calculation results in a deployment density factor for the specified cell.

6. The method of claim 5, wherein:

7. The method of claim 5, wherein:

The interval at which the serving cell of the terminal changes between the designated cells is less than the fifth specified time, but is not less than the fourth specified time, determining that the specified cell deployment density state is medium density; the serving cell of the terminal is And determining that the specified cell deployment density state is a low density, where the interval between the specified cell changes is greater than the fifth specified time.

8. The method of claim 5, wherein:

9. The method of claim 3, wherein:

The steps of determining the designated cell according to the serving cell change interval include: When the time interval of the serving cell of the terminal changing from the first cell to the second cell is less than a predetermined time threshold, determining that the second cell is the designated cell.

10. A method according to any of claims 5-8, wherein:

11. A heterogeneous intra-network mobility parameter adjustment terminal, comprising: a designated cell selection module, an evaluation module, and an adjustment module, wherein:

The evaluation module is configured to: determine a moving speed of the terminal and/or a deployment density of the designated cell according to the selected designated cell;

12. The terminal of claim 11 wherein:

13. The terminal of claim 12, wherein:

Determining a designated cell according to the specified cell flag information sent by the network side; The designated cell is determined according to the serving cell change interval of the terminal.

14. The terminal of claim 13, wherein:

The terminal according to any one of claims 11 to 14, wherein:

16. The terminal of claim 15, wherein:

The evaluation module is configured to determine the deployment density of the cell according to the number of changes between the designated cells in the second predetermined time of the serving cell of the terminal in the following manner:

17. The terminal of claim 15, wherein:

The evaluation module is configured to determine the deployment density of the designated cell according to a change interval of the serving cell of the terminal between the designated cells in the following manner: And determining, by the serving cell of the terminal, that the interval between the change of the designated cell is less than the fourth specified time, determining that the specified cell deployment density state is a high density;

18. The terminal of claim 15, wherein:

19. The terminal of claim 13, wherein:

20. A terminal according to any of claims 15-18, wherein:

The adjustment module is set to: