KR101539022B1 - Method and apparatus for clustering hand-over of mobile device, cluster management method and apparatus thereof - Google Patents

Abstract

A clustering apparatus for handover of a mobile terminal according to the present invention includes a cluster management unit for generating one or more clusters into which at least one radio unit is incorporated and managing the number of generated clusters, A mobile unit for generating a mobility matrix on the basis of the collected mobility information, and for selecting a radio unit having the largest mobility among the neighboring radio units based on the generated mobility matrix, A transferring unit for transferring the selected radio unit to the cluster and deleting the incorporated radio unit from the mobile matrix; and a transferring unit for transferring the number of clusters generated through the cluster managing unit to the number of computing units in the network Clustering when reaching It may include a clustering of management.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clustering method for handover of a mobile terminal,

More particularly, the present invention relates to a clustering method and apparatus for handover of a mobile terminal suitable for minimizing the frequency of handover under a C-RAN network structure, and a cluster management method and apparatus thereof .

1 shows a network structure of an IEEE 802.16j MR. In this network structure, a RS (Relay Station) is separately supported in addition to a BS (Base Station), and a RS is a compact BS excluding the processing unit, and is integratedly managed in a tree structure in one BS as shown in FIG. 1 .

As shown in FIGS. 2A and 2B, the algorithm used in the IEEE 802.16j MR is to create a clustering matrix A based on an H matrix representing the amount of information movement. The method of configuring the clusters is as follows.

1. Extracting the H-matrix information The RS with the greatest amount of movement is extracted one by one, the new coordinate system of the A-matrix is moved to the reference, and the extracted RS is deleted.

2. If the neighboring information movement amount is smaller than the reference RS, it is incorporated to form one cluster.

3. Repeat the above procedure until all RSs of the H matrix are deleted.

The problem with existing clustering algorithms is that the network is designed in a clustering fashion based on the mobility information of a given mobile. This is a disadvantage in that it can not actively cope with the change of mobility information of mobile in the future and can not form new clustering.

Korea Patent Publication No. 2005-0106656 (Notification Date: November 11, 2005)

The present invention proposes a clustering algorithm that minimizes the handover frequency under a C-RAN network structure. Here, the clustering algorithm can perform the re-clustering so as to actively cope with the change of mobility information of the mobile.

The problems to be solved by the present invention are not limited to those mentioned above, and another problem to be solved by the present invention can be clearly understood by those skilled in the art from the following description will be.

According to one aspect of the present invention, there is provided a radio communication method comprising the steps of: a first step of generating a cluster and counting a number of clusters after a cluster according to an aspect; a second step of collecting mobility information from peripheral radio units; A fourth step of selecting a radio unit having the largest mobility among the neighboring radio units based on the generated mobility matrix as a target to be incorporated; A sixth step of deleting the embedded radio unit from the mobility matrix, and a fourth step to a sixth step of repeating the fourth to sixth steps until the maximum number of radio units preset for the cluster is incorporated And when the predetermined maximum number of radio units are incorporated into the cluster, And repeating the second to seventh steps after incrementing the value of the number of clusters by one; and repeating the steps of the second to seventh steps until the number of incremented clusters reaches the number of computing units in the network. And a ninth step of repeating the steps of the clustering for the handover of the mobile terminal.

The predetermined maximum number of the present invention can be determined based on the computing ability of the computing unit constituting the cluster.

The predetermined maximum number of the present invention can be determined based on past mobility statistics in the computing unit constituting the cluster.

According to another aspect of the present invention, there is provided a radio communication system including a cluster management unit for generating at least one cluster into which at least one radio unit is incorporated and managing the number of generated clusters, a mobility collection unit for collecting mobility information from peripheral radio units, A cluster transfer selection unit that generates a mobility matrix based on the collected mobility information and selects a radio unit having the largest mobility among the neighboring radio units based on the generated mobility matrix as an inclusion target; A transfer manager for transferring the radio unit to be incorporated into the cluster and deleting the incorporated radio unit from the mobility matrix; and clustering when the number of clusters generated through the cluster manager reaches the number of computing units in the network And a clustering management unit It provides the clustering apparatus for a handover of the mobile terminal.

The incorporation management unit of the present invention may incorporate radio units selected through the cluster incorporation selection unit into the cluster until the maximum number of the clusters reaches a predetermined number.

The incorporation management unit of the present invention can determine the predetermined maximum number based on the computing ability of the computing unit constituting the cluster.

The incorporation management unit of the present invention can determine the predetermined maximum number based on past mobility statistics in a computing unit constituting the cluster.

According to another aspect of the present invention, there is provided a method of managing clusters in a network environment in which a plurality of clusters into which at least one radio unit is incorporated are created and operated, comprising the steps of: Generating a global mobility matrix by exchanging the generated local mobility matrix with each of the computing units, generating a global mobility matrix by using the generated global mobility matrix, Calculating a difference value between a current value of the matrix and a previous value of the global mobility matrix and performing a re-clustering based on the current mobility matrix information when the calculated difference value exceeds a preset threshold value And a cluster management method for handover of a mobile terminal.

In the process of generating the global mobility matrix of the present invention, the local mobility matrix may be exchanged using an information exchange path of an optical cable.

The information exchange path of the present invention may be an information exchange path of a ring structure.

The reclustering of the present invention may be performed through the clustering method according to claim 1.

According to another aspect of the present invention, there is provided an apparatus for managing a cluster in a network environment in which a plurality of clusters into which at least one radio unit is incorporated are created and operated, A global matrix generating unit for generating a global mobility matrix by exchanging the generated local mobility matrix with each computing unit, and a global matrix generating unit for generating a global mobility matrix by exchanging the generated local mobility matrix with each computing unit, A clustering monitoring unit for calculating a difference value between a current value of the generated global mobility matrix and a previous value of the global mobility matrix, and a clustering monitoring unit for calculating, based on the current mobility matrix information, Clustering < RTI ID = 0.0 > It provides the cluster management apparatus for a handover of a terminal.

The global matrix generator of the present invention may exchange the local mobility matrix with each computing unit using an information exchange path of an optical cable.

The information exchange path of the present invention may be an information exchange path of a ring structure.

The present invention is able to continuously optimize the handover frequency under variable mobility by re-adaptation (re-clustering) clustering based on mobility information exchange between computing units (CUs).

1 is a network structure diagram of an IEEE 802.16j MR.
FIGS. 2A and 2B are views illustrating an H matrix representing the amount of information movement and an A matrix based on the H matrix.
3 is a network structure diagram based on C-RAN.
4 is a block diagram of a clustering apparatus for handover of a mobile terminal according to an embodiment of the present invention.
5 is a flowchart illustrating a main procedure for performing clustering for handover of a mobile terminal according to an embodiment of the present invention.
6 is a block diagram of a cluster management apparatus for handover of a mobile terminal according to an embodiment of the present invention.
7 is a flowchart illustrating a main process of managing a cluster for handover of a mobile terminal according to an embodiment of the present invention.
8 is an exemplary diagram showing a clustering process when there are three CUs.
9A and 9B are exemplary diagrams showing a simulation environment.
10 is a graph for comparing the frequency of handover.

First, the advantages and features of the present invention, and how to accomplish them, will be clarified with reference to the embodiments to be described in detail with reference to the accompanying drawings. While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. It is to be understood that the following terms are defined in consideration of the functions of the present invention, and may be changed according to intentions or customs of a user, an operator, and the like. Therefore, the definition should be based on the technical idea described throughout this specification.

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

3 is a network structure diagram based on C-RAN. A radio unit (RU) and a computing unit (CU) applied to such a network structure can be applied in a separate structure.

That is, the present invention proposes a dynamic clustering algorithm through C-RAN and distributed computing, wherein the C-RAN structure is similar to the BS and RS network structures of the IEEE 802.16j MR described above, PA, a system in which a radio unit (RU) part responsible for the filter part and a computing unit (CU) part for signal processing are separately separated.

Here, the computing unit can simultaneously manage a large number of radio units through an optical cable. However, unlike the IEEE 802.16j MR, a radio unit is a form that can be managed (bundled) with another computing unit according to a clustering algorithm, rather than belonging to (embedded in) a fixed form in one computing unit.

In addition, the computing units may be, for example, bundled into a ring structure as in FIG. 3, wherein the paths connected between the computing units are an information exchange path for handover frequency optimized distributed computing, Lt; RTI ID = 0.0 > exchange.

4 is a block diagram of a clustering apparatus for handover of a mobile terminal according to an embodiment of the present invention. The clustering apparatus includes a cluster management unit 402, an information storage unit 404, a mobility collection unit 406, (408), an incorporation management unit (410), a clustering management unit (412), and the like. Here, the clustering apparatus may be mounted (mounted) on each computing unit constituting a network, for example, a C-RAN-based network.

Referring to FIG. 4, the cluster management unit 402 generates at least one cluster into which at least one radio unit is incorporated when the system is operated, and manages the number of generated clusters, that is, And a function of managing the number of clusters by a method of cumulatively counting the values. Here, the generated cluster information may be stored in the information storage unit 404.

In addition, the mobility collection unit 406 collects mobility information (e.g., identification information of the corresponding radio unit) from radio units (RU) in the vicinity (for example, adjacent to a computing unit (CU) And stores the mobility information in the information storage unit 404. Here, the mobility information may be a service area managed by the corresponding radio unit through the handover, Information that the mobile terminal departs from the service area, and the like.

The cluster incorporation selection unit 408 extracts the mobility information collected from the information storage unit 404 to generate a mobility matrix, and based on the generated mobility matrix, the mobility among the neighboring radio units, It is possible to provide functions such as selecting a unit as an inclusion target and notifying the inclusion management unit 410 of the unit.

Next, the incorporation management unit 410 can provide a function of incorporating (belonging) a radio unit to be incorporated, which is notified from the cluster incorporation selection unit 408, to the cluster, and deleting the incorporated radio unit from the mobility matrix At this time, the incorporation management unit 410 may function to incorporate the radio unit selected through the cluster incorporation selection unit 408 into the cluster until the maximum number of the clusters (the size of the cluster) is set for the cluster.

That is, when the clustering is started, each computing unit sequentially checks the mobility information between its radio unit and its neighboring radio units, selects the most mobile radio unit and binds it with its own radio unit, This clustering procedure repeats until all of the radio units are incorporated into each cluster, as shown in Fig. 8 as an example.

Here, the maximum number of the predetermined radio units (the size of the cluster) can be determined based on, for example, the computing ability of the computing unit constituting the cluster, or can be determined based on the past mobility statistics in the computing unit constituting the cluster .

The clustering management unit 412 monitors (checks) whether or not the number of clusters generated and managed through the cluster management unit 402 reaches the number of the computing units (CU) in the network. If the number of managed clusters And terminating the clustering when it is determined that the number of the computing units has been reached.

Next, a series of processes for performing clustering for handover using the clustering apparatus of the present invention having the above-described configuration will be described in detail.

5 is a flowchart illustrating a main procedure for performing clustering for handover of a mobile terminal according to an embodiment of the present invention.

Referring to FIG. 5, the cluster manager 402 generates one cluster when the system is operated (step 502), and counts the number of clusters using, for example, a counter (step 504) The number value is stored in the information storage unit 404.

Next, the mobility collection unit 406 collects mobility information including mobility information, for example, identification information of the radio unit, from nearby neighboring radio units (RUs), and stores the mobility information in the information storage unit 404 506).

Thereafter, the cluster incorporation selection unit 408 extracts the collected mobility information from the information storage unit 404 to generate a mobility matrix (step 508), and based on the generated mobility matrix, the mobility among neighboring radio units is relatively The largest radio unit is selected as the target (or target) of the cluster (step 510).

In response to this, the incorporation management unit 410 increases (increases) the number N_c of radio units incorporated in the cluster by 1 (step 512) after incorporating The radio unit is deleted from the mobility matrix (step 514). Here, removing from the mobility matrix may mean that the corresponding radio unit belongs to the cluster through clustering.

Next, in step 516, it is checked whether or not the number N_c of incorporated radio units has reached a preset maximum number Mc. If it is checked that N_c does not reach Mc, that is, The process returns to the step 510 and repeats the processes thereafter.

That is, the present invention repeats the processes of steps 510 to 516 by n-th iteration, thereby incorporating the set number of radio units into the cluster.

If it is determined in step 516 that N_c has reached Mc, the clustering management unit 412 determines whether the number of currently managed clusters c is equal to the number of computing units CU in the network (Step 518). If it is determined here that c has not reached C, the process returns to step 502, described above, so that a new cluster is created (and the number of clusters Value increment count) to perform clustering (steps 504 to 518).

If it is determined in step 518 that c = C, the clustering management unit 412 terminates the clustering (step 520) if it is determined that the number of generated clusters has reached the number of computing units.

FIG. 6 is a block diagram of a cluster management apparatus for handover of a mobile terminal according to an embodiment of the present invention. The management apparatus includes a mobility management unit 602, an information storage unit 604, a local matrix generation unit 606, A clustering monitoring unit 610, a re-clustering execution unit 612, and the like. Here, the clustering management apparatus may be installed (mounted) on each computing unit constituting a network based on, for example, a C-RAN, or may be installed in a separate system (for example, a network management station managing some functions of each computing unit) Can be mounted.

Referring to FIG. 6, in the network environment in which a plurality of clusters into which at least one radio unit is incorporated are created and operated, the mobility management unit 602 receives mobility information from radio units incorporated in each cluster at predetermined constant intervals And stores the collected information in the information storage unit 604, for example. That is, the radio units belonging to each cluster calculate their mobility and transmit them to the mobility management unit which administers them.

The local matrix generation unit 606 acquires the mobility information collected from the information storage unit 604 to generate a local mobility matrix and notifies the global matrix generation unit 608 of the mobility matrix can do.

The global matrix generation unit 608 may provide a function of exchanging the local mobility matrix transmitted from the local matrix generation unit 606 with each computing unit to generate a global mobility matrix, Local mobility matrix exchange with the unit may be performed using the information exchange path of the optical cable. Here, the information exchange path may be, for example, an information exchange path of a ring structure.

Next, the clustering monitoring unit 610 calculates the difference value between the current value of the global mobility matrix transmitted from the global matrix generator 608 and the previous value of the global mobility matrix stored in the information storage unit 604 , And delivering the calculated difference value to the clustering execution unit 612, for example.

Then, the re-clustering execution unit 612 compares the calculated difference value transmitted from the clustering monitoring unit 610 with a predetermined threshold value, and when it is determined that the calculated difference value exceeds a predetermined threshold value And perform (re-clustering) on the basis of the current mobility matrix information.

Here, the re-clustering may be performed through a series of processes as shown in the flowchart of Fig. 5 using the clustering apparatus as shown in Fig. 4. For this, And may selectively include a cluster management unit, a mobility collection unit, a cluster integration selection unit, an integration management unit, and a clustering management unit.

Next, a series of processes for managing a cluster for handover using the clustering management apparatus of the present invention having the above-described configuration will be described in detail.

7 is a flowchart illustrating a main process of managing a cluster for handover of a mobile terminal according to an embodiment of the present invention.

7, in a network environment in which a plurality of clusters are created and operated, the mobility management unit 602 extracts mobility information (for example, identification of a corresponding radio unit) from radio units incorporated Mobility information including information) (step 702).

Next, the local matrix generation unit 606 generates a local mobility matrix based on the mobility information collected by the mobility management unit 602, and transmits (notifies) the global mobility matrix to the global matrix generation unit 608 704).

In response, the global matrix generation unit 608 generates a global mobility matrix by exchanging the local mobility matrix generated through the local matrix generation unit 606 with each computing unit (step 706) ). Here, the local mobility matrix exchange with each computing unit can be performed using the information exchange path of the optical cable, and as the information exchange path, for example, a ring structure information exchange path can be used.

The clustering monitoring unit 610 calculates a difference value between the current value of the global mobility matrix generated through the global matrix generator 608 and the previous value of the global mobility matrix stored in the information storage unit 604 Clustering execution unit 612 (step 710).

Thereafter, in the re-clustering execution unit 612, the difference value calculated through the clustering monitoring unit 610 is compared with a predetermined threshold value (step 712), and the difference value calculated as a result of the comparison here is a predetermined threshold value If not, the process returns to step 702 and repeats the processes thereafter.

When it is determined in step 712 that the calculated difference value exceeds the predetermined threshold value, the re-clustering execution unit 612 performs re-clustering on the basis of the current mobility matrix information, (Step 714), and the re-clustering performed here can be performed in the same manner as the series of processes shown in Fig. 5 described above.

The inventors of the present invention performed the simulation assuming the network environment as shown in the following table, and the following results were obtained.

Number of pedestrians 100 (located in India) Number of vehicles 100 cars (located on the central road) Pedestrian speed 1.8 ~ 9 km / h (Uniform Distribution) Vehicle speed 20 to 104 km / h (Uniform Distribution) Number of RUs 25 Size of the whole area 2.5 x 2.5 (km x km)

9A and 9B are exemplary views showing a simulation environment, and FIG. 10 is a graph comparing frequency of handover.

The simulation environment is as shown in Fig. 9a. It is assumed that the vehicle is moving in the north-south direction, the vehicle leaving the north enters the south again, and the vehicle leaving the south enters the north again. In addition, pedestrians in India assumed random walking in India without crossing the road. The velocity distribution of the vehicle and the pedestrian is shown in the table above.

It is assumed that a total of 25 radio units (RUs) are located in the simulation environment, and a total of three computing units (CUs) are located on the left hand side, the right hand side, and the right hand side. When clustering is performed, as shown in FIG. 9B, it is divided into three clusters, so that no handover occurs. That is, there is no inter-cluster handover because there is no mobile moving between the clusters, and no handover occurs within the cluster.

The existing system and the system of the present invention are simulated in terms of handover frequency and are shown in FIG. Since both the existing and the present invention are clustered in accordance with the mobility of the mobile at the beginning of the simulation, the handover does not occur.

Referring to FIG. 10, if the mobility of the mobile changes after 100 seconds, the handover frequency increases in both systems (it is set that the simulation environment given in FIG. 9A is changed by 90 degrees). However, The system of the invention can clearly see that clustering takes place at 1500 seconds, and it can be clearly seen that the handover frequency decreases again due to reclustering in accordance with the changed mobile mobility.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. It is easy to see that this is possible. In other words, the embodiments disclosed in the present invention are not intended to limit the scope of the present invention but to limit the scope of the technical idea of the present invention.

Therefore, the scope of protection of the present invention should be construed in accordance with the following claims, and all technical ideas within the scope of equivalents should be interpreted as being included in the scope of the present invention.

Claims (14)

A first step of counting the number of clusters after generating a cluster,
A second step of collecting mobility information from neighboring radio units,
A third step of generating a mobility matrix based on the collected mobility information,
A fourth step of selecting, as an inclusion target, a radio unit having the largest mobility among the neighboring radio units based on the generated mobility matrix;
A fifth step of incorporating the selected radio unit to be incorporated into the cluster,
A sixth step of deleting the embedded radio unit from the mobility matrix;
A seventh step of repeating the fourth to sixth steps until a maximum radio unit of a predetermined number is incorporated into the cluster;
An eighth step of checking whether the counted number of clusters has reached the number of computing units in the network when the predetermined maximum number of radio units are incorporated into the cluster;
A ninth step of repeating the first to eighth processes when the counted number of clusters does not reach the number of the computing units;
A tenth step of terminating the clustering when the counted number of clusters reaches the number of the computing units
The method comprising the steps of:
The method according to claim 1,
Wherein the predetermined maximum number is a maximum number,
Is determined on the basis of the computing ability of the computing unit constituting the cluster
Clustering method for handover of mobile terminal.
The method according to claim 1,
Wherein the predetermined maximum number is a maximum number,
Is determined based on past mobility statistics in the computing unit constituting the cluster
Clustering method for handover of mobile terminal.
A cluster management unit for generating at least one cluster into which at least one radio unit is incorporated and managing the number of generated clusters,
A mobility collector for collecting mobility information from neighboring radio units,
A cluster transfer selection unit that generates a mobility matrix based on the collected mobility information and selects a radio unit having the largest mobility among the peripheral radio units based on the generated mobility matrix as an inclusion target;
A transfer manager for transferring the selected radio unit to the cluster and deleting the radio unit from the mobile matrix,
And a clustering management unit for terminating clustering when the number of clusters generated through the cluster management unit reaches the number of computing units in the network
And a clustering unit for handover of the mobile terminal.
5. The method of claim 4,
The incorporation management unit,
And a radio unit selected through the cluster incorporation selection unit is incorporated into the cluster until a predetermined maximum number is set for the cluster
Clustering device for handover of mobile terminal.
6. The method of claim 5,
The incorporation management unit,
The predetermined maximum number is determined based on the computing ability of the computing unit constituting the cluster
Clustering device for handover of mobile terminal.
6. The method of claim 5,
The incorporation management unit,
The predetermined maximum number is determined based on past mobility statistics in the computing unit constituting the cluster
Clustering device for handover of mobile terminal.
CLAIMS 1. A method of managing a cluster in a network environment in which a plurality of clusters each including at least one radio unit are created and operated,
Collecting mobility information from radio units incorporated in each cluster at predetermined intervals;
Generating a local mobility matrix based on the collected mobility information,
Generating a global mobility matrix by exchanging the generated local mobility matrix with each computing unit;
Calculating a difference value between a current value of the generated global mobility matrix and a previous value of the global mobility matrix;
Clustering is performed based on the current mobility matrix information when the calculated difference value exceeds a predetermined threshold value
The method comprising the steps of:
9. The method of claim 8,
Wherein the step of generating the global mobility matrix comprises:
Exchanging the local mobility matrix using an information exchange path of the optical cable
A cluster management method for handover of a mobile terminal.
10. The method of claim 9,
The information-
The information exchange path of the ring structure
A cluster management method for handover of a mobile terminal.
9. The method of claim 8,
The clustering may include:
The method according to claim 1,
A cluster management method for handover of a mobile terminal.
An apparatus for managing a cluster in a network environment in which a plurality of clusters each including at least one radio unit are created and operated,
A mobility management unit for collecting mobility information from radio units incorporated in each cluster at predetermined intervals,
A local matrix generator for generating a local mobility matrix based on the collected mobility information,
A global matrix generator for generating a global mobility matrix by exchanging the generated local mobility matrix with each computing unit,
A clustering monitoring unit for calculating a difference value between a current value of the generated global mobility matrix and a previous value of the global mobility matrix;
And when the calculated difference value exceeds a predetermined threshold value, performs a re-clustering based on the current mobility matrix information.
The mobile terminal comprising: a plurality of mobile stations;
13. The method of claim 12,
Wherein the global matrix generator comprises:
Exchanging the local mobility matrix with each of the computing units using an information exchange path of the optical cable
A cluster management device for handover of a mobile terminal.
14. The method of claim 13,
The information-
The information exchange path of the ring structure
A cluster management device for handover of a mobile terminal.

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