KR20040056988A - 2-Phase Dynamic Location Management Apparatus considering Mobile Time in Mobile Networks and Method thereof - Google Patents

Abstract

PURPOSE: A 2-step dynamic location management apparatus considered with moving time and a method therefor are provided to increase the efficiency of location management expenses by presenting a VDLA(Virtual Dynamic Location Area) method to set up a 2-step VLA on the basis of the average moving time of a mobile terminal in an LA. CONSTITUTION: A 2-step dynamic location management apparatus considered with moving time comprises a parameter selection and measurement part(110), a VLA selection part(120), a DBLA(Distance-Based LA) execution part(130), a mobile object location estimation part(140), and a sequential paging execution part(150). The parameter selection and measurement part(110) selects a parameter considered for 2-step dynamic location management, measures an actual value for the parameter, and transfers it to the VLA selection part(120) and the mobile object location estimation part(140). The VLA selection part(120) allocates 2 VLAs to a mobile terminal when the mobile terminal accesses a new LA from the previous LA. The DBLA execution part(130) selects the final LA using LA selection reference time. The mobile object location estimation part(140) creates location estimation information, when sequential paging is required after the final LA is selected, and transfers it to the sequential paging execution part(150). The sequential paging execution part(150) carries out sequential paging using the speed and moving time of the mobile terminal and the location estimation information of the mobile object location estimation part(140).

Description

2-Phase Dynamic Location Management Apparatus considering Mobile Time in Mobile Networks and Method

The present invention relates to location management for a mobile terminal in a mobile communication network environment. More specifically, the mobile station dynamically allocates a two-stage location area (LA) in consideration of the movement time of the mobile terminal to dynamically perform location management. The present invention relates to a two-stage dynamic location management apparatus considering time and a method thereof.

In a next generation mobile communication system, a micro / pico cell with a smaller cell size provides a higher capacity transmission service. However, due to the smaller cell size, the positional movement rate of the mobile terminal from one LA to another LA increases. Here, the LA is a geographic unit where the mobile terminal stays. The LA may be configured as a single cell, or a cell cluster type of one or more cells may be designated as LA.

In terms of the mobile communication network, when the mobile terminal moves to another LA, location information update and re-authentication for the mobile terminal should be performed, and paging should be performed to search for the mobile terminal. Paging refers to the cost of finding out which cell in the LA the mobile station is currently staying in to connect to a call for a communication request.

In addition, when the mobile terminal moves to another LA, the mobile terminal registers the location of the moved LA to update the location information. If the LA consists of a single cell, the location registration cost is high, but it is possible to accurately identify in real time which cell the mobile terminal is currently located in. On the other hand, a larger LA size reduces the cost for location registration but increases the paging cost for mobile terminals in the LA. Therefore, LA should be configured considering the location registration cost and the paging cost simultaneously.

Among existing LA configuration methods, there is a FLA method that provides location management by fixing a LA size. Currently, mobile systems such as GSM use the FLA scheme for mobility management, and all LAs have the same size.

In addition, a time-based LA (TBLA) method in which a mobile terminal registers a location at a predetermined time, and a DBLA (Diatance-Based LA) method in which a location is registered through a specific distance interval from a previous location registration have been proposed. There is a dynamic LA allocation scheme that varies the size of LA for each terminal in consideration of moving parameters such as speed, direction, and traffic. Each of the above schemes has been proposed to provide effective location management for mobile terminals through LA configuration.

Meanwhile, in order to construct an optimal LA, the size of the LA, mobility of the mobile terminal, location update load of the mobile terminal, etc. should be considered. The size and operation of the LA should determine how large the cell aggregates should be in order to construct the LA, and how the mobility of the mobile terminal affects the LA according to the direction of movement of the mobile terminal. Consideration should be given to minimizing administrative costs.

Therefore, there is a need for a device that is very efficient in terms of location management cost and paging cost by configuring an optimal LA.

Accordingly, an object of the present invention is to solve the above-mentioned problems, and by providing a VDLA (Virtual Dynamic LA) method for setting a two-stage virtual LA (VLA) based on an average moving time of a mobile terminal in the LA. It is an object of the present invention to provide a two-stage dynamic location management apparatus and method in consideration of travel time indicating the efficiency of management costs.

1 is a schematic block diagram of a two-stage dynamic location management apparatus in consideration of travel time according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an LA configuration of a two-stage dynamic location management apparatus in consideration of the travel time illustrated in FIG. 1.

3 is a flow chart of a two-step dynamic location management method in consideration of travel time according to an embodiment of the present invention.

In order to achieve the above object, a two-stage dynamic location management apparatus according to a feature of the present invention,

A parameter selection measurement unit which selects a parameter considered for dynamic location management of the mobile terminal and then measures an actual value for the associated parameter; Set a two-stage virtual location area (VLA) around the mobile terminal, generate a LA selection reference time based on the parameter measured by the parameter selection measurement unit, and transmit the set two-stage VLA to the mobile terminal. A VLA selector for allocating; A final LA is selected by using the VLA and LA selection reference time of two stages allocated by the VLA selecting unit, and when there is a location registration request from the mobile terminal for the selected LA, a DBLA (Diatance-Based LA) scheme DBLA execution unit for performing the location registration; A moving object position estimating unit for generating position estimation information for estimating a cell in which the mobile terminal is to be located based on the parameter measured by the parameter selecting measuring unit; And a sequential paging performer that performs sequential paging for the mobile terminal by using the position estimation information generated by the mobile position estimation unit and the parameters measured by the parameter selection measurement unit.

Here, the VLA selector allocates the VLA of the second stage when the mobile terminal leaves the previous LA.

Further, the primary VLA of the second stage VLA is set such that the mobile terminal is located in the central cell, and the secondary VLA is set such that the mobile terminal is located in the boundary cell.

The LA selection reference time generated by the VLA selector may be generated based on the direction and speed of the mobile terminal measured by the parameter selection measurer.

The DBLA execution unit may select the secondary VLA as the final LA of the mobile terminal when the mobile terminal deviates from the primary VLA within the LA selection reference time.

The DBLA execution unit may select the final LA of the mobile terminal according to an area where the mobile terminal is located after the LA selection reference time.

In addition, when the mobile terminal is located in a first region including cells located at the center of the region including the primary VLA and the secondary VLA, the DBLA execution unit may be configured to identify the primary VLA or the secondary VLA. When the terminal is selected as the final LA and the mobile station is located in the second region including cells belonging to the primary VLA around the first region, the DBLA execution unit selects the primary VLA as the final LA. When the mobile terminal is located in a third region including cells belonging to the secondary VLA with respect to the first region, the DBLA execution unit selects the secondary VLA as the final LA.

The sequential paging performer may determine a paging order based on the speed and the travel time of the mobile terminal measured by the parameter selection measurer.

In addition, the sequential paging unit performs the primary VLA when the paging occurs within the LA selection reference time, and performs the final LA selected by the DBLA execution unit when the paging occurs after the LA selection reference time. It is characterized by performing as a reference.

According to another feature of the invention

a) determining location management and location tracking parameters for LA configuration for the mobile terminal; b) allocating to the mobile terminal a two-stage VLA and LA selection reference time set in consideration of the average travel time of the mobile terminal in the LA determined by the determined parameter; c) selecting a final LA from the second stage VLA using the assigned LA selection reference time; d) performing location registration in a DBLA manner with respect to the selected final LA; And e) performing sequential paging from the proximity distance of the mobile terminal whose position is estimated through the position estimation parameter for the mobile terminal.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic block diagram of a two-stage dynamic location management apparatus 100 considering travel time according to an embodiment of the present invention.

As shown in FIG. 1, the two-stage dynamic location management apparatus 100 considering the travel time according to an embodiment of the present invention includes a parameter selection measuring unit 110, a VLA selecting unit 120, and a DBLA performing unit 130. The moving object position estimator 140 and the sequential paging performer 150 are included.

Here, the VLA selector 120 includes a primary VLA performer 121 and a secondary VLA performer 122.

First, the following symbols are defined to explain the process of calculating the location management cost. The total location management cost is equal to the sum of the location registration cost and the paging cost for the mobile terminal.

Occurrence rate of arc

: Paging Cost Per Cell

: Range of cells for paging

: Paging Cost

Location registration fee

The parameter selection measuring unit 110 selects a parameter to be considered for the two-step dynamic position management, and then measures an actual value of the related parameter and transmits the measured value to the VLA selecting unit 120 and the moving object position estimating unit 140.

The VLA selector 120 assigns a VLA to the mobile terminal, as shown in FIG. 2. When a mobile terminal enters a new LA from the previous LA, two VLAs are allocated.

In the LA calculated by the primary VLA performer 121 based on the mobile terminal, the mobile terminal is located in the central cell of the LA. For the LA calculated by the secondary VLA performer 122, the mobile terminal is located in the boundary cell of the LA. Located.

The location management apparatus 100 transmits the LA selection reference time to the mobile terminal through the parameter (direction / speed) of the mobile terminal from the parameter selection measurement unit 110 when the mobile terminal is assigned a new LA. The mobile terminal selects one of the two VLAs through the LA selection reference time transmitted from the location management apparatus 100.

In order to determine the LA selection reference time, as shown in FIG. Use the average time it takes to pass.

Mobile terminal moving at speed v Probability density function of the time it takes to pass Is the same as [Equation 1].

Where R is the radius of the cell, E [V] is the average velocity, V is the velocity, and f (v) is the probability density function for V.

Therefore, the mobile terminal selects the LA selection reference distance Average time to stay in Is the same as [Equation 2], and this average time is the LA selection reference time ( )to be.

Meanwhile, the DBLA execution unit 130 receives the LA assigned by the VLA selector 120 and then transfers the LA selection reference time to the mobile terminal. Select the final LA using.

If the moving time of the mobile terminal is t, the mobile terminal selects the LA selection reference time. If you previously left the primary VLA ( ), The final LA of the mobile terminal is selected as the secondary VLA.

If the mobile terminal is LA selection reference time after( ) As shown in Figure 2 If in -zone the first VLA is the final LA, If in -zone the second VLA is the final LA, If in -zone, the primary or secondary VLA is chosen as the final LA. here The probability of VLA selection for -zone is 1/2. here -zone is a zone containing cells located at the center of the zone including the primary VLA and the secondary VLA, -zone is A zone containing cells belonging to the primary VLA with respect to -zone. -zone is A zone containing cells belonging to the secondary VLA with respect to -zone.

When the final LA is selected as described above, the mobile terminal registers a location for the selected LA based on the DBLA method. That is, location registration of the mobile terminal in the location management apparatus 100 is performed based on the finally selected LA after step 2.

Therefore, the location registration rate of the mobile terminal in the VDLA system-based location management device 100 is shown in [Equation 3].

Here, r means the radius of the cell.

Meanwhile, when the final LA is selected, the mobile position estimator 140 generates location estimation information for estimating a cell where the mobile terminal is located and transmits the estimated location information to the sequential paging performer 150.

The sequential paging performer 150 performs sequential paging from the proximity of the mobile terminal using the speed, the movement time, and the position estimation information of the mobile position estimation unit 140 of the mobile terminal. This sequential paging is a method of paging partly of cells of the LA in order to find a mobile terminal in the LA.

During sequential paging, the paging order is determined based on the movement time t of the mobile terminal moving at the speed of v. Paging If this occurs before, it will be based on the first VLA, If so, paging is performed according to the defined LA.

The paging estimates the cell where the mobile terminal is to be located after t times the new LA is allocated and starts paging from there. Paging is performed from the farthest cell where the mobile terminal can move and be located for t time to the cell where the mobile terminal was first located in the LA region. Cell Position Estimation Parameters for Paging (= ) Is the same as [Equation 4].

In addition, the number of cells for paging is = 1 if 1 If> = 2, it is the same as [Equation 5].

Therefore, paging occurs from the outermost ringer of the LA where the mobile terminal is to be located by time t and the speed v, and the cost is expressed by Equation 6.

here to be.

The operation of the two-stage dynamic location management apparatus 100 considering the travel time of the present invention having the above structure will be described with reference to FIG. 3.

3 is a flow chart of a two-step dynamic location management method in consideration of travel time according to an embodiment of the present invention.

As shown in FIG. 3, first, a speed and a moving direction, which are location management and location tracking parameter values of a mobile terminal, are determined when configuring an LA (S1).

Next, the primary and secondary VLA and LA selection reference time set considering the average travel time in LA Is assigned to the mobile terminal, and the mobile terminal selects the LA selection reference time. Select the final LA using (S2).

Next, the mobile terminal performs location registration for the selected final LA based on the DBLA method (S3).

Thereafter, sequential paging is performed from the proximity distance of the mobile terminal through the position estimation in consideration of the speed and the travel time of the mobile terminal (S4).

Although the present invention has been described with reference to the most practical and preferred embodiment, the present invention is not limited to the above-described embodiment, but also includes various modifications and equivalents within the scope of the following claims.

According to the present invention, when configuring a new LA for the mobile terminal, considering the DBLA extension method through the VLA, and also by using sequential paging, as the LA size increases compared to the conventional method, the efficiency of location management cost increases Have

Claims (20)

A parameter selection measurement unit which selects a parameter considered for dynamic location management of the mobile terminal and then measures an actual value for the associated parameter; Set a two-stage virtual location area (VLA) around the mobile terminal, generate a LA selection reference time based on the parameter measured by the parameter selection measurement unit, and transmit the set two-stage VLA to the mobile terminal. A VLA selector for allocating; A final LA is selected by using the VLA and LA selection reference time of two stages allocated by the VLA selecting unit, and when there is a location registration request from the mobile terminal for the selected LA, a DBLA (Diatance-Based LA) scheme DBLA execution unit for performing the location registration; A moving object position estimating unit for generating position estimation information for estimating a cell in which the mobile terminal is to be located based on the parameter measured by the parameter selecting measuring unit; And A sequential paging performer which performs sequential paging for the mobile terminal by using the position estimation information generated by the mobile position estimation unit and the parameters measured by the parameter selection measurement unit Two-level dynamic location management device comprising a. The method of claim 1, And wherein the VLA selector allocates the second level of VLA when the mobile terminal leaves the previous LA. The method of claim 1, Wherein the primary VLA of the second stage VLA is set such that the mobile terminal is located in a central cell thereof, and the secondary VLA is configured such that the mobile terminal is located in a boundary cell thereof. The method of claim 1, The LA selection reference time generated by the VLA selector is generated based on the direction and speed of the mobile terminal measured by the parameter selection measurer. The method of claim 4, wherein The LA selection reference time ( ) Is the LA selection reference distance ( Average time to stay at) and Where E [V] is the average velocity. Following Two-stage dynamic location management device, characterized in that. The method of claim 3, And the DBLA execution unit selects the secondary VLA as the final LA of the mobile terminal when the mobile terminal deviates from the primary VLA within the LA selection reference time. The method of claim 3, And the DBLA execution unit selects a final LA of the mobile terminal according to an area where the mobile terminal is located after the LA selection reference time. The method of claim 7, wherein When the mobile terminal is located in a first region including cells located at the center of the region including the primary VLA and the secondary VLA, the DBLA performing unit replaces the primary VLA or the secondary VLA with the final LA. , Select When the mobile terminal is located in a second region including cells belonging to the primary VLA around the first region, the DBLA execution unit selects the primary VLA as the final LA, When the mobile terminal is located in a third region including cells belonging to the secondary VLA around the first region, the DBLA execution unit selects the secondary VLA as the final LA. Two-stage dynamic location management device, characterized in that. The method of claim 1, And the sequential paging performer determines a paging order based on the speed and the travel time of the mobile terminal measured by the parameter selection measurer. The method of claim 3, The sequential paging unit is performed based on the first VLA when the paging occurs within the LA selection reference time, If it occurs after the LA selection reference time is performed based on the last LA selected by the DBLA execution unit Two-stage dynamic location management device, characterized in that. The method according to claim 1 or 9, A position estimation parameter generated by the moving object position estimator for the paging ( ) Is the relation Where r is the radius of the cell. Following Two-stage dynamic location management device, characterized in that. The method of claim 11, Number of cells for paging ( Is one when the position estimation parameter is 1, The following relation when the position estimation parameter is 2 or more here, being. Following Two-stage dynamic location management device, characterized in that. The method of claim 11, The cost of the paging ( ) Is the relation here, ego, being. Following Two-stage dynamic location management device, characterized in that. a) determining location management and location tracking parameters for LA configuration for the mobile terminal; b) allocating to the mobile terminal a two-stage VLA and LA selection reference time set in consideration of the average travel time of the mobile terminal in the LA determined by the determined parameter; c) selecting a final LA from the second stage VLA using the assigned LA selection reference time; d) performing location registration in a DBLA manner with respect to the selected final LA; And e) performing sequential paging from the proximity distance of the mobile terminal whose position is estimated through the position estimation parameter for the mobile terminal; Two-step dynamic location management method comprising a. The method of claim 14, Among the second VLAs set in step b), the primary VLA is set such that the mobile terminal is located in the central cell, and the secondary VLA is set so that the mobile terminal is located in the boundary cell. How to manage dynamic location. The method of claim 15, In step c), And when the mobile terminal deviates from the primary VLA within the LA selection reference time, selects the secondary VLA as the final LA of the mobile terminal. The method of claim 15, In step c), the mobile terminal selects the last LA of the mobile terminal according to an area located after the LA selection reference time. The method of claim 17, In step c), When the mobile terminal is located in a first region including cells located at the center of the region including the primary VLA and the secondary VLA, the primary VLA or the secondary VLA is selected as the final LA, When the mobile terminal is located in a second region including cells belonging to the primary VLA with respect to the first region, the DBLA execution unit selects the primary VLA as the final LA, When the mobile terminal is located in a third region including cells belonging to the secondary VLA around the first region, the DBLA execution unit selects the secondary VLA as the final LA. Two-step dynamic location management method characterized in that. The method of claim 1, In the step e), the paging order is determined based on the speed and the movement time of the mobile terminal. The method of claim 15, If the sequential paging occurs within the LA selection reference time, the first PLA is performed based on the primary VLA. If it occurs after the LA selection reference time is performed based on the last LA selected by the DBLA execution unit Two-step dynamic location management method characterized in that.