KR20140004546A - Mobile communication system for utilizing distributed small base station in high speed mobile environment and method for providing mobile communication service - Google Patents

Abstract

Disclosed is a mobile communication system and method utilizing a distributed small base station in a high speed mobile environment. According to one embodiment of the present invention, a mobile communication system includes: at least one mobile communication terminal (MS); a plurality of dispersed small base stations (DBS) dispersed, preset, providing a mobile communication service for a mobile communication terminal in a fixed area, and forming a virtual cell network (VCN); and at least one macro base station (MBS) determining the position and velocity of at least one mobile communication terminal, controlling some DBSs among the plurality of DBSs to form a mobile virtual cell network (MVCN) corresponding to the velocity of the mobile terminal, and updating the MVCN by including or excluding a DBS forming the MVCN to make it movable according with the move of the mobile communication terminal. Thus, a mobile communication service of a fine qualify can be provided for a mobile communication terminal moving. [Reference numerals] (AA) Change MVCN

Description

Technical Field [0001] The present invention relates to a mobile communication system and a method for providing a mobile communication service using a distributed small base station in a high-speed mobile environment,

The present invention relates to a mobile communication system and a mobile communication service providing method for simultaneously serving a variable size cell and an existing cell in consideration of a mobile communication terminal moving at a high speed and a mobile communication terminal moving at a low speed by utilizing a distributed small base station .

With the development of information and communication technology, users are demanding to provide communication functions in various communication environments. In particular, in the case of mobile communication services, the size of a cell tends to be gradually reduced in order to cope with changes in various communication environments.

In the next generation mobile communication service to cope with the change of the communication environment, MBS and Distributed small base station (MBS) are installed in order to construct a cell which is more flexible than a cell based on a conventional macro base station Base Station (DBS).

In a small cell-based service environment, MBS and DBS are configured to support multi-band (UHF, SHF) and beam to provide various cell shapes and bands. In LOS (LINE-OF-SIGHT) (UHF) (300MHz ~ 3GHz) band in the NLOS (NON-LOS) using a wireless backhaul using a high-frequency (3GHz ~ 30GHz) A mobile station (MS) supporting the UHF band receives data from the DBS through a beam in the UHF band.

In the small cell-based service environment, as the cell size is smaller than the cell size in the previous mobile communication service, a frequent handover (HO) is required according to the movement of the MS. Therefore, a method of performing a handover between an MBS having a large cell size and a DBS having a relatively small cell size has been proposed. However, the handover between the MBS and the DBS has a problem in that frequent HOs are frequently generated in mobile communication terminals moving at high speed, resulting in a large load on the mobile communication service.

As another approach, a cooperative macro diversity technique has been studied in which a plurality of DBSs are created as a relay group, DBS is added to or removed from a relay group, and data is transmitted to the MS. However, the cooperative macrodiversity technology is merely defined as a method for adding or removing DBS to a relay group for a mobile communication terminal, and is not limited to a mobile communication terminal moving at high speed, .

It is an object of the present invention to provide a mobile communication system capable of distributing resources considering both a mobile communication terminal moving at a low speed and a mobile communication terminal moving at a high speed by utilizing a distributed small base station.

It is another object of the present invention to provide a mobile communication service providing method using a distributed small base station capable of providing high quality mobile communication services to mobile communication terminals moving at high speed and low speed.

According to an aspect of the present invention, there is provided a mobile communication system including at least one mobile communication terminal; A plurality of distributed small base stations (DBS) forming a virtual cell network (VCN) for providing a mobile communication service to the mobile communication terminal in a fixed area which is distributed and set in advance; And determining a position and a moving speed of the at least one mobile communication terminal, and if a moving speed of the at least one mobile communication terminal is equal to or higher than a predetermined speed, A plurality of distributed small base stations configured to configure a mobile virtual cell network (MVCN) of a type corresponding to a moving speed, and configured to configure the mobile virtual cell network such that the mobile virtual cell network can move according to movement of the mobile communication terminal And at least one macro base station (MBS) for updating the mobile virtual cell network by adding and excluding the distributed small base stations.

And the plurality of distributed small base stations provide the mobile communication service to the at least one mobile communication terminal by using cooperative diversity in the mobile virtual cell network.

Each of the at least one macro base station receives an MS information report including information on a location, a moving speed and a moving direction of the mobile communication terminal from at least one of the at least one mobile communication terminal or the plurality of distributed small base stations And analyzing the received MS information report to determine the plurality of distributed small base stations to be included in the mobile virtual cell network.

Wherein each of the at least one macro base station transmits to the mobile communication terminal through the virtual cell network corresponding to the location of the mobile communication terminal, if the moving speed of the mobile communication terminal analyzed by the MS information reporter is less than the reference speed, And controlling the plurality of distributed small base stations so as to provide a mobile communication service, and when the moving speed of the mobile communication terminal is equal to or greater than the reference speed, A plurality of distributed small base stations are configured to configure a mobile virtual cell network and to provide the mobile communication service to the mobile communication terminal through the mobile virtual cell network.

Each of the at least one macro base station further determines a size and a shape of the mobile virtual cell network by further considering a moving direction of the mobile communication terminal.

Wherein a distributed small base station constituting the mobile virtual cell network among the plurality of distributed small base stations distributes resources to both the mobile virtual cell network and the virtual cell network, And is capable of providing a communication service.

Wherein each of the at least one macro base station controls the distributed small base station located within a predetermined distance from the mobile virtual cell network to reserve resources for the mobile virtual cell network and use remaining resources for the virtual cell network .

Each of the plurality of distributed small base stations distributes the resource using one of time division multiplexing (TDM), frequency division multiplexing (FDM), and orthogonal frequency division multiplexing (OFDM).

Wherein each of the at least one macro base station controls the plurality of distributed small base stations so that the generated mobile virtual cell network disappears when the moving speed of the mobile communication terminal moving above the reference speed is slowed below the reference speed again .

Each of the plurality of distributed small base stations utilizes resources distributed by the distributed small base station constituting the mobile virtual cell network for the mobile virtual cell network for the virtual cell network when the mobile virtual cell network disappears .

Wherein each of the at least one macro base station is capable of directly providing the mobile communication service to the at least one mobile communication terminal.

According to another aspect of the present invention, there is provided a method for providing a mobile communication service including at least one mobile communication terminal, a plurality of distributed small base stations distributed to provide a mobile communication service to the mobile communication terminal, A method for providing a mobile communication service in a mobile communication system having a macro base station, the method comprising: providing a plurality of distributed small base stations (DBS) to the at least one mobile communication terminal, Forming a virtual cell network (VCN) for the fixed area and controlling the mobile communication terminal to provide a mobile communication service; Receiving an MS information report including information on a location, a moving speed, and a moving direction of the mobile communication terminal from at least one of the at least one mobile communication terminal or the plurality of distributed small base stations; And analyzing the MS information report and constructing the mobile virtual cell network with a size corresponding to the moving speed around the position of the mobile communication terminal when the at least one mobile communication terminal moves at a higher speed than the reference speed And controlling the plurality of distributed small base stations so that the mobile communication terminal can receive the mobile communication service through the mobile virtual cell network.

Wherein the controlling of the plurality of distributed small base stations comprises: determining a distributed small base station to be included in the mobile virtual cell network of the size corresponding to the moving speed among the plurality of distributed small base stations; And adding and excluding the distributed small base station configuring the mobile virtual cell network so that the mobile virtual cell network is movable according to the movement of the mobile communication terminal.

The determining of the distributed small base station may include determining a size and a shape of the mobile virtual cell network by taking into consideration not only the moving speed of the mobile communication terminal but also the moving direction.

According to the present invention, a low-rate mobile communication terminal moving at a low speed and a high-speed mobile communication terminal moving at a high speed are distinguished from each other. And the high-speed mobile communication terminal can receive the communication service without the handover through the mobile VCN (MVCN), so that the high-speed mobile communication terminal can receive the stable service because there is no overhead due to the handover So that resources for VCN can be operated together so that low-rate mobile communication terminals can receive stable service.

In addition, it is possible to provide a customized VCN that predicts mobility by positively utilizing macro diversity, and it is possible to operate VCN in a decentralized manner separately from MVCN managed in a centralized manner .

1 illustrates a concept of a mobile virtual cell network according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating how a neighboring VCN is affected by movement of an MVCN when a VCN and an MVCN are operated simultaneously according to the present invention.
3 is a diagram illustrating a mobile communication system according to an embodiment of the present invention.
4 is a diagram for explaining a MVCN configuration method according to an embodiment of the present invention.
5 is a view for explaining a MVCN configuration method according to an embodiment of the present invention.
FIG. 6 shows a concept of a method of operating a VCN and an MVCN according to an embodiment of the present invention.
7 is a view for explaining the MVCN operation method of FIG.
8 shows the operation of the MBS for the MVCN operating method of FIG.
9 illustrates a resource utilization method of a DBS for an MVCN according to an embodiment of the present invention.
FIG. 10 shows a method of managing the state of DBS according to the movement of the MS.

In order to fully understand the present invention, operational advantages of the present invention, and objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the accompanying drawings which illustrate preferred embodiments of the present invention.

Hereinafter, the present invention will be described in detail with reference to the preferred embodiments of the present invention with reference to the accompanying drawings. However, the present invention can be implemented in various different forms, and is not limited to the embodiments described. In order to clearly describe the present invention, parts that are not related to the description are omitted, and the same reference numerals in the drawings denote the same members.

Throughout the specification, when an element is referred to as " including " an element, it does not exclude other elements unless specifically stated to the contrary. The terms "part", "unit", "module", "block", and the like described in the specification mean units for processing at least one function or operation, And a combination of software.

1 illustrates a concept of a mobile virtual cell network according to an embodiment of the present invention.

In the conventional small cell-based mobile communication system, frequent HOs are required for MSs moving at a high speed (for example, 10 Km / h or more) as the cell size is miniaturized. In order to allow a mobile communication service to simultaneously provide services to an MS moving at a high speed and an MS moving at a low speed (for example, 10 Km / h or less) (including low speed in the present invention) It may also provide medium or large cell based services rather than small cell based services. However, a medium-sized or large-cell-based service is not a suitable method because there is a restriction on the efficient use of resources as is known in conventional mobile communication services.

Therefore, there is a need for a service scheme for a mobile station moving at a high speed in a small cell-based mobile communication service.

The mobile communication service according to the present invention supports a mobile virtual cell network (MVCN) in addition to a known virtual cell network (VCN).

As shown in FIG. 1, in the MVCN according to the present invention, like the VCN, at least one MBS or DBS is formed as a group to form a cluster. In addition, the MVCN can provide the mobile communication service to the MS moving at high speed without the HO by performing the update in which the at least one MBS or DBS forming the cluster is added or removed according to the movement of the MS. That is, the MVCN corresponds to the movement of the MS and the cluster is updated and moves with the MS. Thus, the MVCN can be viewed as a VCN that is variable for the moving MS.

For MSs moving at high speed, MVCN needs to perform fast cluster updates or frequent HOs. When the cluster is updated frequently, the Coordinated Multi-Point (CoMP) technique used in the existing VCN is difficult to use because it needs to be taken into consideration of the channel condition. Also, the process of measuring / exchanging and calculating channel information, It is not suitable for high speed mobile environment. Also, as described above, HO has a great influence on the performance of a mobile terminal having high mobility due to an overhead occurring in HO.

On the other hand, in the case of the cooperative diversity technique, even when there is a change in the cooperating DBS, there is less additional information exchange or calculation procedure, and when the DBS constituting the cluster is varied, It is possible to provide the service while updating the cluster so that the MVCN HO does not occur. Therefore, in the present invention, at least one MBS or DBS forming a cluster provides the service only in the diversity mode.

However, not only the mobile MS exists in the mobile communication service network, but there is also a suspended MS. Also, in a moving MS, it is necessary to provide services by distinguishing an MS moving at a high speed from an MS moving at a low speed.

Accordingly, the present invention proposes a cluster formation and update operation for a high-speed mobile user and a method for simultaneously operating an existing VCN and MVCN.

FIG. 2 is a diagram illustrating how a neighboring VCN is affected by movement of an MVCN when a VCN and an MVCN are operated simultaneously according to the present invention.

The MVCN updates the cluster according to the movement of the MS so as to avoid the overhead caused by the HO in the MS as much as possible. However, in the mobile communication service, not only the MS moving at high speed but also the MS moving at low speed exist, You can not provide MVCN for. In other words, the mobile communication service must operate not only the MVCN for the MS moving at a high speed but also the VCN for the MS moving at a low speed. However, since the MVCN cluster is variable according to the moving MS, the MVCN cluster region and the VNC cluster region may overlap each other as shown in FIG. 2. When the MVCN cluster region and the VNC cluster region overlap, It affects not only the MVCN but also the performance of the VCN that the priority service is provided.

Also, as shown in FIG. 2, in the case of MVCN, it is desirable to update VCN and MVCN separately because frequent updating of the cluster is required. This is because it is difficult to frequently update the VCN using the Cooperative Base Station Cooperation (CoMP) technique, and it is a transmission technique for measuring / considering the channel condition. In the case of MVCN, , The VCN around the moving user is influenced and the performance of the neighboring VCN is lowered as shown in the figure.

The MVCN of the present invention provides a higher performance (advantage of small cell-based topology) and a wider service area (coverage (advantage of VCN)) than a single DBS) than the service of MBS, So that the service can be provided.

Since MVCN is continuously updated and MVCN is updated, the number of HOs can be extremely reduced, thereby reducing the overhead incurred by the MS and providing a high quality service.

In addition, since MVCN has a merit of obtaining a diversity gain by using a cooperative diversity scheme and complicated procedures such as measuring or exchanging channel information are unnecessary, .

3 is a diagram illustrating a mobile communication system according to an embodiment of the present invention.

The mobile communication system according to the present invention comprises at least one MBS (MBS), at least one DBS (DBS), and at least one MS (MS).

Each of the at least one MS (MS) includes an MS information management unit 310. The MS information management unit 310 collects information on a location, a moving speed, and a moving direction of the MS (MS) and obtains information on the corresponding MBS (MBS) or DBS (DBS) of at least one MBS DBS) to transmit the state of the current MS (MS) to the upper network.

Each of the at least one DBS (DBS) is operated under the control of the corresponding one of the at least one MBS and added to or removed from the cluster of VCN and MVCN. The DBS collects information on the position, the moving speed and the moving direction of the MS (MS), and controls the MS information manager 210 and the MBS (MBS), which transmit the information on the corresponding MBS among the at least one MBS (MBS) A DBS control unit 220 for controlling an operation mode of the DBS according to whether an MVCN exists in a cell area of the DBS (DBS) in response to the MVCN, and a transmission / reception unit 230 for simultaneously providing services for the MVCN and the VCN. In the DBS (DBS), the MS information management unit 210 performs functions similar to the MS information management unit 210 of the MS (MS), and thus can be provided only in one of DBS (DBS) and MS (MS) It can be done.

At least one MBS performs a function of a central control unit (CMU) to control the operation of the DBS (DBS) according to the state of the MS (MS). At least one MBS includes an MVCN configuration unit 110 for analyzing MS information received from the MS information management units 210 and 310 of the DBS (DBS) and the MS (MS) and managing creation, modification and release of MVCN, And a resource unit 120 for allocating or returning resources of the DBS corresponding to the MVCN. The MVCN configuration unit 110 analyzes the location, the moving speed, and the moving direction of the MS included in the MS information received from the MS information management units 210 and 310 to determine a DBS (DBS), and operates a message protocol between DBS (DBS) and MBS (MBS) to send / receive messages for MVCN creation, modification, and extinction. In particular, even if the current position of the MS (MS) is not included in the cell range of the specific DBS (DBS), the MVCN configuration unit 110 may determine that the DBS (DBS) corresponds to the MVCN DBS (DBS) can be included in the cluster of MVCN in advance. The MVCN configuration unit 110 allows the MVCN to form a larger cluster as the moving speed of the MS (MS) increases.

The resource management unit 120 allocates resources for the MVCN when the DBS (DBS) to which the resource is allocated for the VCN is included in the cluster of the MVCN, and allocates resources when the DBS (DBS) is excluded from the cluster of the MVCN Let the resource use the VCN again. The resource management unit 120 manages MVCN and VCN simultaneously by operating a message protocol between DBS and MBS for resource reservation of a neighboring VCN for MVCN operation.

4 is a diagram for explaining a MVCN configuration method according to an embodiment of the present invention. In FIG. 4, (a) shows the MVCN without considering the MS movement speed, and (b) shows the MVCN considering the MS movement speed. In both (a) and (b), the left figure shows the case where the moving speed (v1) of the MS is slow, and the right figure shows the case where the moving speed (v2) of the MS is fast.

(a), the MVCN provides the MVCN having clusters of the same size irrespective of the moving speed of the MS, when the moving speed is not considered. That is, in FIG. 4 (a), the cluster sizes of the MVCNs are the same even though the moving speeds of the MSs are different from each other in the left and right images. Therefore, in order to provide a service to the MS, the mobile communication system needs to update the cluster or perform frequent HO according to the moving speed of the MS when the MS has a high moving speed. And update or HO of these clusters causes overhead and degrades the performance of the mobile communication system.

In contrast, in (b), considering the moving speed, the size of the cluster is realized on the right figure where the moving speed of the MS is faster than that on the left figure where the moving speed of the MS is slow. Therefore, it is possible to significantly reduce the update frequency of the cluster and the frequency of execution of the HO with respect to the MS having a fast moving speed, compared to (a).

it is important to select a DBS to be included in the cluster among the plurality of DBSs when constructing the MVCN considering the speed of the MS as shown in FIG.

A method for selecting a DBS to be included in a cluster for MVCN is to set a set of a plurality of DBSs (b ₁ , b ₂ , b ₃ , ..., b _n ) of the mobile communication system as S _tot = {b ₁ , b ₂ , b ₃ , ..., b _n } can be expressed as Equation (1).

는 i번째 MS인 MS_i를 위한 MVCN의 DBS의 집합을 나타내고, v_i 는 MS_i 의 속도를 나타내고, d_i,k는MS_i 로부터 k번째 DBS인 DBS_k 까지의 거리를 나타낸다. 그리고 th_i 는 MS_i를 위한 MVCN의 DBS의 집합

의 문턱값을 나타낸다. c는 이동 통신 시스템의 MBS에 기설정되는 상수이다.)(here

Denotes the set of DBSs of MVCN for MS _i , MS _i , v _i denotes the speed of MS _i , and d _{i, k} denotes the distance from MS _i to DBS _k , the _kth DBS. And th _i is the set of DBS of MVCN for MS _i

Lt; / RTI > and c is a constant preset in the MBS of the mobile communication system.)

As shown in Equation (1), in the mobile communication system of the present invention, the MVCN configuration unit 110 of MBS (MBS) configures a DBS (DBS) to be included in the cluster of MVCN considering the moving speed of the MS _i , Therefore, as the moving speed of the MS _i increases, the DBS (DBS) of a longer distance is included in the cluster and the cluster size is increased in proportion to the moving speed of the MS _i . That is, when the moving speed of the user is not considered, the MVCN is kept constant. However, when considering the moving speed of the user, the size of the MVCN varies according to the moving speed of the user. The size of the cluster, it is possible to provide a stable mobile communication service even when the movement of the MS _i to gate proportional to the moving speed of the MS _i fast speed, the frequency of update or the HO for the cluster of MVCN even lower. The value of the constant c may be preset in the MVCN configuration unit 110 and the manager of the mobile communication system may adjust the size of the cluster to provide the service by adjusting the constant c.

)에 포함되지 않는 경우가 발생한다. 그러나 상기한 바와 같이 수학식 1 은 MVCN의 구성 방법에 대한 수식으로서 MBS가 MS_i가 기설정된 속도(예를 들면 10Km/h) 이상인 경우에만 MVCN가 구성하도록 설정하므로 상기한 오류는 해소될 수 있다.In Equation (1), when v _i is 0, that is, when MS _i is stopped, the threshold value th _i becomes 0. Therefore,

) May not be included in the data. However, as described above, Equation (1) is an expression for a method of constructing the MVCN. Since the MBS is configured to configure the MVCN only when the MS _i is equal to or higher than a predetermined speed (for example, 10 Km / h) .

5 is a view for explaining a MVCN configuration method according to an embodiment of the present invention.

The MVCN configuration method of FIG. 4 adjusts the size of the cluster considering the moving speed of the MS _i . However, the movement of MS _i is directional. In the case where the size of the cluster is set to be large considering only the moving speed of the MS _i since the movement of the MS _i has directionality, the cluster may also include a large number of DBSs in directions different from the moving direction of the MS _i , The DBS in the other direction is not able to provide the service for the MS _i in many cases, and thus unnecessary resources are wasted.

In Figure 5, simply by considering the moving speed of the MS _i, not to scale the cluster, by calculating the progress estimated direction in consideration with the moving speed and direction of the MS _i, set MVCN, the mobility of the MS _i So that more efficient MVCN can be set. If also control the shape of the cluster in consideration with the moving speed and direction of the MS _i, as shown in FIG. 5, the DBS, while that include a long distance DBS, opposite to the direction of movement of the MS _i arranged in the movement direction of the MS _i The DBS placed in the direction only includes the DBS arranged at a relatively short distance. Therefore, the DBS arranged in the direction opposite to the direction of movement of the MS _i does not need to allocate resources for MVCN unnecessarily, so resources can be used for the VCN or other MVCN, and as a result, the efficiency of the mobile communication system as a whole increases.

A method of selecting a DBS to be included in a cluster for MVCN that considers both the moving speed and the direction of the MS _i can be expressed as Equation (2).

는 i번째 MS인 MS_i를 위한 MVCN의 DBS의 집합을 나타내고,

는 MS_i 의 이동 방향 벡터를 나타내며,

는 MS_i 로부터 k번째 DBS인 DBS_k 까지의 방향 벡터를, v_i 는 MS_i 의 속도를 나타내고, d_i,k는MS_i 로부터 DBS_k 까지의 거리를 나타낸다. 그리고

는 MS_i를 위한 MVCN의 DBS의 집합

의 문턱값을 나타낸다. c는 이동 통신 시스템의 MBS에 기설정되는 상수이다.)(here

Represents the set of DBSs of the MVCN for MS _i , which is the i-th MS,

_Denotes a moving direction vector of MS _i ,

Is the direction vector from MS _i to DBS _k , the _kth DBS, v _i is the velocity of MS _i , and d _{i, k} is the distance from MS _i to DBS _k . And

A set of MVCN DBS for MS _i

Lt; / RTI > and c is a constant preset in the MBS of the mobile communication system.)

As shown in Equation (2), in the mobile communication system of the present invention, considering the moving speed and direction of the MS _i that the MVCN configuration unit 110 of the MBS (MBS) provides, , The MVCN configuration unit 110 may include the DBS (DBS) in the MVCN cluster so that the cluster can be formed in a biased shape corresponding to the moving speed and direction of the MS (MS). The value of the constant c may be preset in the MVCN configuration unit 110 and the manager of the mobile communication system may adjust the size of the cluster to provide the service by adjusting the constant c.

In the above description, the MVCN is constructed through all the DBSs in the cluster region generated by the predetermined threshold value. However, although not shown, in some cases, a plurality of subsets are formed in the cluster, and the transmit power of the DBS included in the subset is adjusted for each subset, thereby saving resources of the DBS not included in the subset And can save the energy of MBS and DBS. At this time, the size of the subset is limited by the number of beams available in the backhaul, and it is clear that the transmission power of the DBS can not exceed the maximum available transmission power of the DBS.

FIG. 6 shows a concept of a method of operating a VCN and an MVCN according to an embodiment of the present invention.

6 (a) and 6 (e) show MSs moving at a low speed, and FIGS. 6 (b), (c) and (d) . Therefore, when the MS moving at a low speed moves at high speed, the state of the MS changes from (a) to (b). When the MS is moving at a high speed, the state of the MS is shown as (b), (c) and (d), and when the MS moves again at low speed, the state of the MS is changed from (d) to .

When the state of the MS changes from (a) to (b), that is, when the MS moving at a low speed moves at high speed, the MS receiving the service through the VCN in (a) In order to receive the service through the MVCN, the MVCN configuration unit 110 of the MBS (MBS) determines the DBS to configure the MVCN, generates the MVCN, registers the ID of the generated MVCN, and identifies the MVCN generated for the MS . And performs an HO so that the MVCN can provide the service from the VCN providing the service to the current MS.

As shown in (b), (c), and (d), while the MS moves at high speed, the mobile communication system adds and removes the DBS included in the cluster of the MVCN so that the MS can continuously receive service through the MVCN Update the MVCN. Therefore, the update of the MVCN is performed while the MS moves at high speed, and the HO does not occur because the cluster of the MVCN is changed according to the movement of the MS.

the MVCN constructing unit 110 of the MBS (MBS) does not need to provide the service via the MVCN to the MS, and therefore, the VCN is changed from the MS to the MS HO, and destroys the MVCN generated for the MS.

7 is a view for explaining the MVCN operation method of FIG.

6, DBS (DBS11, DBS12, DBS13) among the plurality of DBSs (DBS11, DBS12, DBS13, DBS21, DBS22) , And DBS (DBS11, DBS12) is the DBS included in the second cluster for the second VCN. The MS receives the VCN service on the assumption that the MS initially moves at a low speed as shown in FIG. 6 (a), and the MS receives a service from the first VCN in FIG.

When the MS moves at a high speed, the DBSs (DBS11, DBS12, DBS13) of the first cluster or the MS information management units 210 and 310 included in the MS, which are currently providing service to the MS, An MS information report including information on the moving direction is transmitted to the MBS to notify that the moving speed of the MS has changed.

The MBS determines the DBS to be included in the MVCN cluster by analyzing the position, the moving speed and the moving direction of the MS in the received MS information report, notifies the determined DBS (DBS11, DBS12, DBS13) that it is included in the MVCN cluster, . Also, the MBS registers the ID of the MVCN with the DBS (DBS11, DBS12, DBS13) included in the cluster of the MVCN so that it can be distinguished from the VCN or another MVCN.

Once the MVCN is created and registered, the MBS requests the HO from the MS. In this case, the requested HO is to allow the MS, which is currently provided through the VCN, to receive the service from the newly created MVCN. In the above description, the MBS directly requests the HO to the MS. However, the DBS (DBS11, DBS12, DBS13) of the first cluster may request the HO to the MS.

Upon receiving the HO request, the MS performs HO through information exchange with the DBSs (DBS11, DBS12, DBS13) of the first cluster. When the HO is completed, the MBS receives the HO result from the DBS (DBS11, DBS12, DBS13) of the first cluster, and the MS receives the service through the MVCN. As the MS moves at a high speed, the DBSs (DBS11, DBS12, and DBS13) of the first cluster request MVCN update to the MBS. At this time, the DBSs (DBS11, DBS12, DBS13) of the first cluster can transmit the MS information report to the MBS.

The MBS receiving the MVCN update request updates the MVCN by analyzing the MS position, the moving speed and the moving direction from the MS information report. In FIG. 6, the DBS (DBS11) of the first VCN is first removed from the cluster of the MVCN, DBS (DBS21) of the second VCN is added as a cluster of MVCN. Thereafter, as the MVCN update request is received again, the DBS (DBS 22) of the second VCN is added to the cluster of the MVCN. That is, the MVCN can be updated by adding or removing the DBS regardless of the VCN classification according to the movement of the MS.

If the MS moves to a lower speed, the MS or the DBS transmits an MS information report to the MBS, and the MBS responds to the MS information report so that the MS receiving the service from the MVCN receives the service To request the HO to be provided. The MS receiving the HO request performs the DBS (DBS21, DBS22) and HO of the second VCN, the DBS (DBS21, DBS22) of the second VCN notifies the MBS of the HO result and provides the VCN service to the MS .

As the MS receives the VCN service, the MBS notifies the DBSs (DBS12, DBS13, DBS21, DBS22) included in the current MVCN that the generated MVCN will be destroyed.

8 shows the operation of the MBS for the MVCN operating method of FIG.

The MBS of FIG. 8 first controls the DBS (DBS11, DBS12, DBS13) of the first VCN to the MS moving at a low speed, and provides VCN service to the MS (S10). Then, the MS information report is received and it is determined whether the MS moves at a high speed (S20). If it is determined that the MS is moving at a low speed, the service is directly provided through the first VCN (S10). However, if it is determined that the MS is moving at a high speed, the MBS determines the DBS to be included in the MVCN, and requests the determined DBS to perform the MVCN service to generate the MVCN (S30). In this case, the MBS controls the DBSs included in the MVCN and the DBSs within the predetermined distance around the MVCN not to use all the resources for the MVCN but to leave resources for the VCN. When the MVCN is generated, the MS and the DBS are requested to perform HO from the VCN to the MVCN service (S40). When the HO to the MVCN is performed, a service is provided to the MS through the MVCN (S50).

The MS information report is received and discriminated whether the MS is in the fast moving state (S60). If the MS is maintaining a high-speed movement, the MBS determines whether an update request for the MVCN is received (S70). When an update to the MVCN is received, the MVCN transmits an update request to the DBS (S80), and provides the service through the MVCN (S50). Even when updating the MVCN, the MBS controls the DBSs included in the MVCN and DBSs within the predetermined distance around the MVCN to leave resources for the VCN. If an update to the MVCN is not received, the service through the MVCN is directly provided without updating the MVCN (S50).

On the other hand, if it is determined that the MS moves again at a low speed, the MBS requests the MS to perform HO to receive the VNC service (S90). When the HO to the VCN is performed, the DBS is controlled to extinguish the MVCN (S100). When the MVCN expires, the MBS controls the DBS to use all the resources for the VCNVCN service, thereby increasing the overall efficiency of the system.

9 illustrates a resource utilization method of a DBS for an MVCN according to an embodiment of the present invention.

Since the mobile communication system according to the present invention supports not only VCN but also MVCN, the states of a plurality of DBSs can be divided into a case of supporting VCN and a case of supporting MVCN. Also, if MVCN is supported, it can be divided into two states again.

In Fig. 9, the circular area represents VNC, and the ellipse area indicated by the dotted line represents MVCN. In VNC, VCN in blue indicates VCN that does not overlap with MVCN, and VCN in red indicates VCN overlapped with MVCN.

First, if only VCN is supported, DBS (Full VCN Mode) DBS (vm) is indicated as DBS included in the blue VCN. Since there is no overlapping region with MVCN, it is not necessary to support MVCN. Therefore, all resources are used only for VCN.

In the case of supporting MVCN, DBSs directly included in MVCN and DBS including DBS are not included in MVCN but DBS having MVSN overlapped region can be distinguished.

Since the DBS directly included in the MVCN is a DBS that needs to use the resources for the MVCN, it operates in the MVCN / VNC mode (mvm) using the resources for operating the VCN in addition to the resources for the MVCN.

However, a DBS that is not directly included in the MVCN but has a region where the VCN that contains it overlaps with the MVCN is a DBS that may be included in the MVCN afterwards. The DBS operates as a partial VCN mode (pvm) to allocate resources for MVCN and to operate the remaining resources as VCN. That is, the resources are reserved so that they can immediately provide services to the MS even after they are included in the MVCN.

In the above description, the states of the DBSs are transformed according to the overlap of the VCN and the MVCN. However, the states of the DBSs may be changed according to the distance from the MVCN. That is, the state of the DBS can be varied depending on whether the DBS is included in the MVCN or within a predetermined distance from the MVCN.

As shown in (b), the state (vm, mvm, pvm) of each DBS can be changed according to the generation, update, and disappearance of the MVCN.

FIG. 10 shows a method of managing the state of DBS according to the movement of the MS.

10A shows a state change of the DBS included in the neighboring VCN according to the update of the MVCN, and FIG. 10B shows a state in which the state of the DBS is changed for each VCN in the MBS according to the update of the MVCN shown in FIG. And a command for transmitting the command.

In FIG. 10, it is assumed that the state of the DBS is changed according to the distance between the plurality of DBSs and the MVCN.

Of the five VCNs marked with different colors (yellow, green, blue, purple, and indigo), in the case of VCN marked with indices, there is no overlapping region with both MVCN1 and MVCN2, , The state of the DBSs is maintained in the full VCN mode (vm).

In the case of the green VCN, the DBSs are arranged at a distance from the MVCN1, but are disposed at a relatively short distance from the MVCN2. Therefore, the DBSs included in the green VCN are changed from the full VCN mode (vm) to the partial VCN mode (pvm).

The DBSs of the VCNs indicated in blue are arranged at a distance from MVCN1, but one DBS is directly included with MVCN2 and one DBS is disposed at a close distance. Therefore, one DBS is converted from full VCN mode (vm) to partial VCN mode (pvm), and the remaining one DBS is directly included in MVCN2, thereby converting from full VCN mode (vm) to partial MVCN / VCN mode (mvm) do.

VCNs indicated in gray color are MVCN / VCN mode (mvm) and partial VCN mode (pvm) states, respectively, since one DBS in MVCN1 is directly included in MVCN1 and the other DBS is a distance close to MVCN1. In MVCN1, The included DBS is close to MVCN2, and the DBS which is close to MVCN1 is far from MVCN2. Therefore, the partial VCN mode (pvm) and the full VCN mode (vm) were changed, respectively.

VCN in yellow is MVCN / VCN mode (mvm) and partial VCN mode (pvm), respectively, since there are two DBSs included in MVCN1 and one DBS close to MVCN1. In MVCN2, however, only one DBS of two DBSs included in MVCN1 is included in MVCN2, one DBS maintains MVCN / VCN mode (mvm), and the other DBS maintains partial VCN in MVCN / VCN mode (mvm) Mode (pvm). In MVCN1, DBS in partial VCN mode (pvm) maintains partial VCN mode (pvm) state in MVCN2.

As shown in FIG. 10, in the mobile communication system according to the present invention, the MBS manages the states of DBSs included in the VCN, so that each VCN can secure the independence of scheduling. That is, each VCN can reserve resources for MVCN according to the MBS control, and the remaining resources can be freely and internally adjusted for VCN.

11 shows an example of a DBS resource allocation method for VCN and MVCN.

The DBSs in the MVCN / VCN mode (mvm) and the partial VCN mode (pvm) are divided into a time division multiplexing (TDM) a, a frequency division multiplexing (FDM) Multiplexing scheme (OFDM) (c), it is possible to assign different resources to VCN and MVCN.

As a result, the mobile communication system according to the present invention generates an MVCN that provides a service in a diversity mode together with a VCN by utilizing a distributed small base station, provides a VCN service to an MS moving at a low speed, Can provide a high quality mobile communication service for both MSs moving at low speed and high speed by providing service using MVCN.

The method according to the present invention can be implemented as a computer-readable code on a computer-readable recording medium. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored. Examples of the recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and a carrier wave (for example, transmission via the Internet). The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art.

Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (23)

At least one mobile communication terminal (MS);
A plurality of distributed small base stations (DBS) forming a virtual cell network (VCN) for providing a mobile communication service to the mobile communication terminal in a fixed area which is distributed and set in advance; And
If the position and the movement speed of the at least one mobile communication terminal is determined and the movement speed of the at least one mobile communication terminal is greater than or equal to a preset speed, some distributed small base stations of the plurality of distributed small base stations are moved by the mobile communication terminal. Controlling the plurality of distributed small base stations to form a mobile virtual cell network (MVCN) of a type corresponding to a speed, and configuring the mobile virtual cell network to move the mobile virtual cell network according to the movement of the mobile communication terminal. And at least one macro base station (MBS) for updating the mobile virtual cell network by adding and excluding the distributed small base station.
The method of claim 1, wherein the plurality of distributed small base stations
Wherein the mobile communication system provides the mobile communication service to the at least one mobile communication terminal using cooperative diversity in the mobile virtual cell network.
2. The method of claim 1, wherein each of the at least one macro base station
Receives an MS information report including information on a location, a moving speed and a moving direction of the mobile communication terminal from at least one of the at least one mobile communication terminal or the plurality of distributed small base stations, analyzes the received MS information report And determines the plurality of distributed small base stations to be included in the mobile virtual cell network.
4. The apparatus of claim 3, wherein each of the at least one macro base station
When the moving speed of the mobile communication terminal analyzed by the MS information reporter is less than the reference speed, the mobile communication service may be provided to the mobile communication terminal through the virtual cell network corresponding to the location of the mobile communication terminal. To control the plurality of distributed small base stations,
And configuring the mobile virtual cell network with a size corresponding to the moving speed around the position of the mobile communication terminal when the moving speed of the mobile communication terminal is equal to or greater than the reference speed, And controls the plurality of distributed small base stations to provide the mobile communication service to the mobile terminal.
5. The method of claim 4, wherein each of the at least one macro base station
To express a set of the plurality of distributed small base station _{(b 1, b 2, b} 3, ..., b n) S tot = {b 1, b 2, b 3, ..., b n},
The distributed small base station to be included in the mobile virtual cell network is expressed by Equation

(here

Denotes the set of DBSs of MVCN for MS _i , MS _i , v _i denotes the speed of MS _i , and d _{i, k} denotes the distance from MS _i to DBS _k , the _kth DBS. And th _i is the set of DBS of MVCN for MS _i

Lt; / RTI > and c is a constant preset in the MBS of the mobile communication system.)
Of the mobile communication system.
5. The method of claim 4, wherein each of the at least one macro base station
Wherein the size and the shape of the mobile virtual cell network are determined by further considering a movement direction of the mobile communication terminal.
7. The apparatus of claim 6, wherein each of the at least one macro base station
To express a set of the plurality of distributed small base station _{(b 1, b 2, b} 3, ..., b n) S tot = {b 1, b 2, b 3, ..., b n},
The distributed small base station to be included in the mobile virtual cell network is expressed by Equation

(here

Represents the set of DBSs of the MVCN for MS _i , which is the i-th MS,

_Denotes a moving direction vector of MS _i ,

Is the direction vector from MS _i to DBS _k , the _kth DBS, v _i is the velocity of MS _i , and d _{i, k} is the distance from MS _i to DBS _k . And

A set of MVCN DBS for MS _i

Lt; / RTI > and c is a constant preset in the MBS of the mobile communication system.)
Of the mobile communication system.
5. The method of claim 4, wherein the distributed small base station constituting the mobile virtual cell network among the plurality of distributed small base stations distributes resources to both the mobile virtual cell network and the virtual cell network, And the mobile communication service can be provided to the network at the same time.
9. The apparatus of claim 8, wherein each of the at least one macro base station
Wherein the distributed small base station located within a predetermined distance from the mobile virtual cell network reserves resources for the mobile virtual cell network and uses remaining resources for the virtual cell network.
10. The method of claim 9, wherein each of the plurality of distributed small-
Wherein the resource is distributed using one of a time division multiplexing (TDM) scheme, a frequency division multiplexing scheme (FDM) scheme, and an orthogonal frequency division multiplexing scheme (OFDM scheme).
9. The apparatus of claim 8, wherein each of the at least one macro base station
And controls the plurality of distributed small base stations so that the generated mobile virtual cell network disappears when the moving speed of the mobile communication terminal moving at least the reference speed is slowed below the reference speed again. .
12. The method of claim 11, wherein each of the plurality of distributed small-
Wherein when the mobile virtual cell network disappears, resources distributed by the distributed small base station constituting the mobile virtual cell network for the mobile virtual cell network are utilized for the virtual cell network.
4. The apparatus of claim 3, wherein each of the at least one macro base station
Wherein the at least one mobile communication terminal is capable of providing the mobile communication service directly to the at least one mobile communication terminal.
A method for providing a mobile communication service in a mobile communication system having at least one mobile communication terminal, a plurality of distributed small base stations distributed to provide mobile communication services to the mobile communication terminal, and at least one macro base station,
The macro base station forms a virtual cell network (VCN) with respect to the fixed area of the plurality of distributed small base stations (DBS) for the at least one mobile communication terminal moving at a low speed lower than a predetermined reference speed, To provide a mobile communication service;
Receiving an MS information report including information on a location, a moving speed, and a moving direction of the mobile communication terminal from at least one of the at least one mobile communication terminal or the plurality of distributed small base stations; And
Analyzing the MS information report and when the at least one mobile communication terminal moves at a high speed beyond the reference speed, constructing the mobile virtual cell network with a size corresponding to the movement speed around the position of the mobile communication terminal, And controlling the plurality of distributed small base stations so that the mobile communication terminal can receive the mobile communication service through the mobile virtual cell network.
15. The method of claim 14, wherein controlling the plurality of distributed small base stations
Determining a distributed small base station to be included in the mobile virtual cell network of a size corresponding to the moving speed among the plurality of distributed small base stations; And
And adding and excluding the distributed small base station configuring the mobile virtual cell network so that the mobile virtual cell network is movable according to the movement of the mobile communication terminal. 16. The method of claim 15, wherein determining the distributed small base station
To express a set of the plurality of distributed small base station _{(b 1, b 2, b} 3, ..., b n) S tot = {b 1, b 2, b 3, ..., b n},
The distributed small base station to be included in the mobile virtual cell network is expressed by Equation

(here

Denotes the set of DBSs of MVCN for MS _i , MS _i , v _i denotes the speed of MS _i , and d _{i, k} denotes the distance from MS _i to DBS _k , the _kth DBS. And th _i is the set of DBS of MVCN for MS _i

Lt; / RTI > and c is a constant preset in the MBS of the mobile communication system.)
Of the mobile communication service.
16. The method of claim 15, wherein determining the distributed small base station
Wherein a size and a shape of the mobile virtual cell network are determined by taking into consideration not only the moving speed of the mobile communication terminal but also the moving direction.
18. The method of claim 17, wherein determining the distributed small base station
To express a set of the plurality of distributed small base station _{(b 1, b 2, b} 3, ..., b n) S tot = {b 1, b 2, b 3, ..., b n},
The distributed small base station to be included in the mobile virtual cell network is expressed by Equation

(here

Represents the set of DBSs of the MVCN for MS _i , which is the i-th MS,

_Denotes a moving direction vector of MS _i ,

Is the direction vector from MS _i to DBS _k , the _kth DBS, v _i is the velocity of MS _i , and d _{i, k} is the distance from MS _i to DBS _k . And

A set of MVCN DBS for MS _i

Lt; / RTI > and c is a constant preset in the MBS of the mobile communication system.)
Of the mobile communication service.
16. The method of claim 15, wherein controlling the plurality of distributed small-
And a distributed small base station configuring the mobile virtual cell network among the plurality of distributed small base stations distributes the resources to both the mobile virtual cell network and the virtual cell network, And controlling the mobile communication service to provide the mobile communication service to the cell network at the same time.
20. The method of claim 19, wherein controlling the plurality of distributed small base stations comprises:
Controlling the distributed small base station located within a predetermined distance from the mobile virtual cell network among the plurality of distributed small base stations to reserve resources for the mobile virtual cell network and use remaining resources for the virtual cell network The method of claim 1, further comprising:
The method of claim 19, wherein the mobile communication service providing method comprises:
When the moving speed of the mobile communication terminal, in which each of the at least one macro base station moves above the reference speed, is slowed again below the reference speed, the mobile virtual cell network generated by controlling the plurality of distributed small- The method comprising the steps of: receiving a service request from a mobile communication service provider;
22. The method of claim 21, wherein destroying the mobile virtual cell network comprises:
Wherein the distributed small base station constituting the mobile virtual cell network uses resources allocated for the mobile virtual cell network for the virtual cell network.
23. A recording medium on which program instructions for implementing the communication service providing method according to any one of claims 14 to 22 are recorded.

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