KR101495232B1 - Base station apparatus and control method thereof - Google Patents

Abstract

The present invention relates to a base station apparatus capable of raising a registration (addition) success ratio for a neighbor station (macro base station) using another frequency band and reducing unnecessary handover of a terminal while assuring quality of communications service by arbitrarily handing over a terminal using specific communications service (VoIP, VoLTE, etc.) to a macro base station.

Description

TECHNICAL FIELD [0001] The present invention relates to a base station apparatus and a base station apparatus,

The present invention relates to a base station apparatus and a base station apparatus. More particularly, the present invention relates to a base station apparatus and a base station apparatus that can increase the registration success rate of a neighbor base station (macro base station) The present invention relates to a base station apparatus and a base station apparatus capable of reducing unnecessary handover of a terminal while still ensuring quality of a communication service by handing over a terminal using VoIP (VoIP, VoLTE, etc.) to a macro base station.

In recent LTE networks, a network environment in which base stations having different cell sizes are located in the same area has emerged. In this network environment, various types of small base stations having smaller coverage (cells) as well as general macro base stations are arranged / coexisted Various types of base stations form macro cells and small cells in the overlapped area and provide wireless communication service to the users.

As described above, in a network environment in which macro cells and small cells coexist, a small cell is generally formed in a macro cell. Therefore, when a macro base station and a small base station use one frequency band, In addition, a ping-pong phenomenon in which handover is repeated between a macro base station and a small base station may frequently occur at the border of a small cell.

In order to solve the above-mentioned inter-base station interference problem and the ping-pong phenomenon, the macro base station and the small base station use different frequency bands in a network environment in which macro cells and small cells coexist.

Therefore, each base station should manage not only the neighbor list of the frequency band that it uses, but also the neighbor list of the frequency band different from itself.

For example, a conventional method of managing a neighbor list of a different frequency band (second frequency band) in a base station using the first frequency band will be briefly described. A base station, for example, a small base station, In order to register (add) the base station, the terminal connected thereto transmits information to search for the base station of the second frequency band, and if the terminal detects the base station of the second frequency band, The base station is newly registered as a neighbor base station in the second frequency band by acquiring the base station through the terminal and reflecting it in the neighbor list.

However, if the terminal connected to the small base station is currently using the communication service through the first frequency band, even if the terminal receives the information from the small base station to search for the base station in the second frequency band, It is impossible to search the base station of the band, and as a result, detailed information of the base station searched through the terminal can not be obtained in the case of a small base station, so that registration to the neighbor base station using the two frequency bands will fail.

Accordingly, in the present invention, a base station searches for a base station in a different frequency band and acquires detailed information at an optimal time by a terminal using a communication service, so that a base station transmits a neighbor base station Base station) of the present invention.

On the other hand, when the communication service used by the terminal is a communication service such as VoIP or VoLTE, it is very important to guarantee the service quality of the communication service to a certain level or higher. Therefore, in order for a terminal using a communication service such as VoIP or VoLTE to guarantee the service quality of the communication service, it is necessary to perform a handover in which a connection is switched to a base station having the highest signal strength of the base station.

However, in a network environment in which macro cells and small cells coexist as described above, the quality of communication services such as VoIP and VoLTE may not be ensured due to excessive handover of the terminals.

Therefore, in the present invention, in a network environment in which macro cells and small cells coexist, unnecessary handover of a terminal can be reduced even though quality of a communication service is still assured for a terminal using a communication service such as VoIP or VoLTE through a base station I would like to propose a solution.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to increase the registration success rate of a neighbor base station (macro base station) using a frequency band different from itself, The present invention also provides a method of operating a base station apparatus and a base station apparatus capable of reducing unnecessary handover of a terminal while ensuring quality of a communication service by handing over a terminal using a service (VoIP, VoLTE, etc.) to a macro base station.

According to a first aspect of the present invention, there is provided a base station apparatus including: a signal transmission / reception unit for transmitting / receiving signals to / from a terminal over a specific frequency band and using the communication service according to the signal transmission / reception at the terminal; A point-in-time confirmation unit for confirming a specific point of time when the terminal can receive signals in a frequency band other than the specific frequency band; And a controller for instructing the terminal to search for a base station in another frequency band by measuring a signal received from the base station using the other frequency band at the specific time.

According to a second aspect of the present invention, there is provided an operation method of a base station apparatus, comprising: transmitting and receiving a signal to and from a terminal over a specific frequency band so that the terminal uses a communication service according to the signal transmission and reception; Confirming a specific time point at which the terminal can receive signals in a frequency band other than the specific frequency band; And instructing the terminal to perform a search for a base station in another frequency band by measuring a signal received from the base station using the other frequency band at the specific time point.

According to the operation method of the base station apparatus and the base station apparatus of the present invention, it is possible to increase the registration success rate of a neighbor base station (macro base station) using a frequency band different from that of the base station apparatus and the base station apparatus, Etc.) is handed over to the macro base station, the quality of the communication service is still ensured, and unnecessary handover of the terminal can be reduced.

1 is a configuration diagram illustrating a communication system including a base station apparatus according to a preferred embodiment of the present invention.
2 is a block diagram illustrating a configuration of a base station apparatus according to a preferred embodiment of the present invention.
3 is a flowchart showing a control flow of a communication system including a base station apparatus according to a preferred embodiment of the present invention.
4 and 5 are flowcharts illustrating an operation method of a base station apparatus according to a preferred embodiment of the present invention.

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

1 is a diagram illustrating a communication system including a base station apparatus according to a preferred embodiment of the present invention.

As shown in FIG. 1, a communication system includes a terminal 1 that wants to use a communication service with a counterpart device (not shown) based on a specific network, and a terminal 1 that transmits and receives signals between the terminal 1 and a counterpart device The base station apparatuses 10, 100, and 200 that provide the terminal 1 with a communication service.

Here, the specific network is a network for providing a communication service based on packet (PS), for example, an LTE network.

The communication service based on a specific network, that is, the LTE network, includes a general communication service (hereinafter referred to as a data service) using an LTE network such as a download service, a streaming service, an SNS service and a portal service, (Hereinafter referred to as VoLTE service) such as VoLTE.

The base station apparatuses 10, 100, and 200 are base stations that support connection to a specific network (LTE network).

For example, as shown in FIG. 1, the base station apparatuses 100 and 200 may be small base stations, and the base station apparatus 10 may be a macro base station. The cell coverage C100 and C200 of the base station apparatuses 100 and 200 which are small base stations may be included in the cell coverage C10 of the base station apparatus 10 which is a macro base station.

Hereinafter, for convenience of explanation, the base station apparatus 10 and the macro base station 10 will be described in combination, and the base station apparatus 100 and the small base station 100 will be described together.

Since the cell coverage C100 and C200 of the small base stations 100 and 200 belong to the cell coverage C10 of the macro base station 10 and the same frequency band is used between the macro base station 10 and the small base station 100 , A phenomenon that the terminal 1 is ping-ponged between the macro base station 10 and the small base station 100 or 200 may occur in the boundary area of the cell C100 or C200, And the small base stations 100 and 200 may interfere with each other and the signal quality may deteriorate in the boundary regions of the cells C100 and C200.

Therefore, it is preferable to use different frequency bands between the macro base station 10 and the small base stations 100, 200. For example, the small base stations 100 and 200 use a specific frequency band, i.e., a first frequency band (e.g., 1.8 GHz), and the macro base station 10 uses another frequency band different from the specific frequency band, 800 MHz) can be used.

As described above, the present invention is based on a network environment in which macro cells and small cells coexist in the same area, and the base station apparatus according to the present invention is preferably a small base station.

The terminal 1 is a terminal that can use a communication service by connecting to a specific network (LTE network) through the base station apparatuses 10, 100, and 200 and transmitting / receiving signals to / from a counterpart apparatus (not shown).

For example, to describe the data service, the terminal 1 accesses a specific network (LTE network) through the base station apparatuses 10, 100, and 200 to transmit data to the other apparatus or data service (e.g., download service, streaming service, A data service apparatus (not shown) that provides a data service, and a data service.

The terminal 1 accesses a specific network (LTE network) through the base station apparatuses 10, 100, and 200 to transmit and receive a VoLTE data signal to and from a counterpart terminal (not shown) of the VoLTE service The VoLTE service can be used.

That is, the terminal 1 can access a specific network (LTE network) through the base station apparatuses 10, 100, and 200, and can use a data service or a VoLTE service based on a specific network (LTE network).

Hereinafter, for convenience of description, the present invention will be described with reference to a base station apparatus 100 of base station apparatuses 100 and 200. As shown in FIG. 1, when the terminal 1 is a base station apparatus 100, And is located in the cell coverage C100 of the small base station 100 using the band.

When the base station 100 or the small base station 100 according to the present invention receives a call connection request for the terminal 1 from an associated equipment (e.g., MME) on a network (LTE network) (For example, a data service or a VoLTE service) to the terminal 1 by connecting a call session based on a first frequency band, that is, a first frequency band, with the terminal 1 and transmitting / ).

Accordingly, the terminal 1 can use a communication service (e.g., a data service or a VoLTE service) based on the first frequency band through the small base station 100.

Meanwhile, since the present invention uses a network environment in which macro cells and small cells coexist in the same area, and different frequency bands are used between the small base station and the macro base station, the base station apparatus 100 of the present invention uses Not only the Naver list of the first frequency band that is being used but also the Naver list of the second frequency band that is different from the Naver list.

Accordingly, in order to manage the neighbor list of the second frequency band, the small base station 100 of the present invention requests the terminal 1 using the communication service to perform an operation of searching for the base station of the second frequency band do.

To do so, the small base station 100 first confirms a specific time point at which the terminal 1 can receive signals in a different frequency band, i.e., the second frequency band, rather than the first frequency band.

Preferably, the small base station 100 preferably confirms the specific time point to the terminal 1 only when the communication service used by the terminal 1 is a specific communication service, that is, a VoLTE service.

More specifically, a specific communication service, that is, a VoLTE service is a communication service requiring a higher quality of service quality than a data service because it is sensitive to delay or jitter as compared with a data service.

Therefore, a call connection request (e.g., an E-RAB Setup Request) to the terminal 1 provided from the related equipment (e.g., MME) includes information on what type of call session should be connected according to the service quality assurance level of the communication service A QoS class indicator (QCI) is specified as information on the service quality indicator (QCI).

For example, a call connection request for requesting a call session connection of a VoLTE service may be assigned QCI # 1 or QCI # 2 for guaranteeing quality of service suitable for use of a VoLTE service, and a call connection request QCI # 5 or QCI # 6, or QCI # 8 or QCI # 9 for ensuring quality of service suitable for use of the data service.

When receiving the call connection request to the terminal 1 from the related equipment (e.g., MME) on the network (LTE network), the small base station 100 transmits the call connection request with QCI # 5 or QCI # 6 or QCI # 8 or QCI # 9 is designated, a basic call session based on a first frequency band (e.g., a default bearer) is connected to the terminal 1 in response to a call connection request, thereby providing a data service to the terminal 1, When QCI # 1 or QCI # 2 is specified in the connection request, an additional call session (e.g., Dedicated Bearer) in addition to the basic call session based on the first frequency band (e.g., Default Bearer) And provides the VoLTE service to the terminal 1.

Therefore, the base station apparatus 100, that is, the small base station 100 of the present invention can transmit an additional call session (e.g., Dedicated Bearer) to the terminal 1 when the communication service currently used by the terminal 1 is a VoLTE service Only the terminal 1 is confirmed at a specific time point when it is possible to receive the signal of the second frequency band other than the current first frequency band.

It is preferable that the specific time at this time is the time when the communication service used by the terminal 1, that is, the VoLTE service is terminated.

The small base station 100 measures a signal received from the base station using the second frequency band and searches for the base station of the second frequency band at a specific time point, that is, at the time point when the VoLTE service used by the terminal 1 ends And instructs the terminal 1 to perform an operation.

More specifically, in the case of using the VoLTE service between the terminal 1 and the counterpart terminal (not shown), a case of VoLTE service termination event occurrence in which the VoLTE service termination is selected in the terminal 1 or the counterpart terminal The following will be described in detail.

When receiving the E-RAB Release Command message according to the VoLTE service termination event from the related equipment (e.g., MME) on the network (LTE network), the small base station 100 transmits an RRC Connection Reconfiguration message to the terminal 1 RAB Release Reconfiguration Complete message is received from the terminal 1 as a response to the E-RAB Release Response Response message, the E-RAB Release Response message is provided to the related equipment (e.g., MME) on the network (LTE network) The VoLTE service termination procedure for the terminal 1 is performed by releasing all the resources allocated to the call session with the terminal 1.

At this time, the VoLTE service termination procedure performed by the small base station 100 transmitting and receiving messages with the terminal 1 and the related equipment (e.g., MME) as described above is completed very quickly within several ms. On the other hand, for the user of the terminal 1, it takes a long time of several hundred milliseconds before comparison that the VoLTE service being used is recognized as being completed.

Therefore, it means that sufficient time is guaranteed until the user starts using another communication service (e.g., data service or VoLTE service) again after the use of the VoLTE service is terminated (terminated) in the terminal 1.

The reason for confirming that the time point at which the VoLTE service used in the terminal 1 ends is a specific time point at which the terminal 1 can receive signals in the second frequency band other than the current first frequency band, Due to the fact that a certain amount of time is guaranteed until the use of the VoLTE service in the terminal 1 is stopped (terminated) and then another communication service (such as data service or VoLTE service) is started again, So that the terminal 1 can perform the base station search operation in the second frequency band and further obtain the detailed information of the search base station.

Herein, the termination time of the VoLTE service used in the terminal 1 refers to a point in time when the small base station 100 performs a VoLTE service termination procedure by transmitting and receiving a message to and from the terminal 1 and the related equipment (e.g., MME) The RRC Connection Reconfiguration Complete message may be received from the terminal 1 or may be a time point when the RRC Connection Reconfiguration Complete message is received from the terminal 1, The RRC Connection Reconfiguration message may be sent to the RRC Connection Reconfiguration message, or may be a time when a call disconnect command (e.g., E-RAB Release Command) is received.

Hereinafter, for convenience of description, a point of time at which the RRC Connection Reconfiguration Complete message is received from the terminal 1 is defined as a time point when the VoLTE service used by the terminal 1 is terminated.

That is, when the communication service currently used by the terminal 1 is the VoLTE service, the small base station 100 performs the VoLTE service termination procedure for the terminal 1 when the VoLTE service used by the terminal 1 is terminated It is confirmed that the receiving point of the RRC Connection Reconfiguration Complete message from the terminal 1 is a specific point in time when it is possible to receive the signal in the second frequency band other than the current first frequency band.

Then, the small base station 100 measures a signal received from the base station using the second frequency band at a specific point identified as described above, that is, at the time point when the VoLTE service used by the terminal 1 ends, And commands the terminal 1 to perform an operation of searching for a base station.

As a result, according to the present invention, the terminal 1 is instructed to perform the base station search operation in the second frequency band from the small base station 100 at the optimal time when the VoLTE service being used through the first frequency band is terminated , And immediately performs the base station search operation in the second frequency band according to this command.

For example, the terminal 1 converts an RF module (not shown) in a state capable of receiving a signal of the first frequency band to a state capable of receiving a signal of the second frequency band, By performing the base station search operation, it is possible to measure a signal received from the base station using the second frequency band and search for the base station (e.g., the base station with the highest signal strength) in the second frequency band.

For example, in the case of FIG. 1, the terminal 1 can search the macro base station 10 using the second frequency band as a result of performing the base station search operation in the second frequency band. In this case, (E.g., PCI) of the macro base station 10 as a result of performing the base station search operation of the macro base station 10 to the small base station 100. [

Hereinafter, the configuration of a base station apparatus according to a preferred embodiment of the present invention will be described in more detail with reference to FIG.

The base station apparatus 100 according to the present invention includes a signal transmission / reception unit 110 for transmitting / receiving a signal to / from a terminal through a specific frequency band and using the communication service according to the signal transmission / reception at the terminal, (120) for confirming a specific time point at which a signal in another frequency band other than the specific frequency band is receivable, and a controller for measuring a signal received from the base station using the other frequency band at the specific time point, And a control unit (130) for instructing the terminal to perform an operation of searching for a base station in a band.

Here, it is described that the specific frequency band is the first frequency band mentioned above, and the other frequency band different from the specific frequency band will be described as the second frequency band mentioned above.

The base station apparatus 100 of the present invention corresponds to the small base station 100 as described above with reference to FIG.

The signal transmitting and receiving unit 110 transmits and receives signals to and from the terminal 1 over a specific frequency band, that is, the first frequency band, so that the terminal 1 uses the communication service according to the signal transmission and reception.

That is, when the base station apparatus 100 receives a call connection request for the terminal 1 from the related equipment (e.g., MME) on the network (LTE network), the base station apparatus 100 transmits a call session based on the first frequency band And connects with the terminal 1.

The signal transmitting and receiving unit 110 transmits and receives signals to and from the terminal 1 through the call session of the first frequency band so that the terminal 1 can communicate with the communication service such as the data service or the VoLTE service ).

The viewpoint confirmation unit 120 confirms a specific time point at which the terminal 1 can receive a signal in a different frequency band, i.e., the second frequency band, which is not the first frequency band.

It is preferable that the viewpoint confirmation unit 120 confirms the specific point of time to the terminal 1 only when the communication service used by the terminal 1 is a specific communication service, that is, a VoLTE service.

More specifically, when the base station apparatus 100 receives a call connection request to the terminal 1 from an associated equipment (e.g., MME) on a network (LTE network), the base station apparatus 100 transmits a call connection request to the QCI # 5 or the QCI # 6 or QCI # 8 or QCI # 9 is designated, a basic call session based on the first frequency band (for example, Default Bearer) is connected to the terminal 1 according to the call connection request, (Eg, Dedicated Bearer) in addition to the basic call session based on the first frequency band (eg, Default Bearer) according to the call connection request when QCI # 1 or QCI # 2 is specified in the call connection request And provides VoLTE service to the terminal 1 by connecting with the terminal 1. [

Therefore, the viewpoint confirmation unit 120 can determine whether the communication service currently used by the terminal 1 is a VoLTE service, that is, only when the terminal 1 has connected to the terminal 1 an additional call session (e.g., Dedicated Bearer) It is preferable to confirm a specific time point at which the signal of the second frequency band other than the current first frequency band can be received.

It is preferable that the specific time at this time is the time when the communication service used by the terminal 1, that is, the VoLTE service is terminated.

More specifically, the termination time of the VoLTE service used by the terminal 1 means that the VoLTE service terminated by transmitting / receiving a message to / from the terminal 1 and the related equipment (e.g., MME) May refer to a time point at which a call disconnect response (e.g., an E-RAB Release Response) is provided as a point in the procedure, a time point when a RRC Connection Reconfiguration Complete message is received from the terminal 1, (RRC Connection Reconfiguration) message to the base station (1), or may indicate a time when a call connection release command (e.g., E-RAB Release Command) is received.

Hereinafter, for convenience of description, a point of time at which the RRC Connection Reconfiguration Complete message is received from the terminal 1 is defined as a time point when the VoLTE service used by the terminal 1 is terminated.

That is, when the communication service currently used by the terminal 1 is a VoLTE service, the viewpoint confirmation unit 120 performs a VoLTE service termination procedure for the terminal 1 when the VoLTE service used by the terminal 1 is terminated It is confirmed that the point of time when the RRC Connection Reconfiguration Complete message is received from the terminal 1 is a specific time point at which signal reception in the second frequency band other than the current first frequency band is possible.

The control unit 130 measures the signal received from the base station using the second frequency band at a specific time point confirmed by the viewpoint confirmation unit 120 and searches for the base station of the second frequency band, Lt; / RTI >

That is, the control unit 130 measures a signal received from the base station using the second frequency band at a specific time point, that is, at the time point when the VoLTE service used by the terminal 1 ends, And instructs the terminal 1 to perform an operation of searching for the terminal.

As a result, according to the present invention, the terminal 1 is instructed to perform the base station search operation in the second frequency band from the small base station 100 at the optimal time when the VoLTE service being used through the first frequency band is terminated , And immediately performs the base station search operation in the second frequency band according to this command.

For example, the terminal 1 converts an RF module (not shown) in a state capable of receiving a signal of the first frequency band to a state capable of receiving a signal of the second frequency band, By performing the base station search operation, it is possible to measure a signal received from the base station using the second frequency band and search for the base station (e.g., the base station with the highest signal strength) in the second frequency band.

Then, the controller 130 registers the specific base station found as a result of performing the base station search operation in the second frequency band in the terminal 1, as a neighbor base station in the second frequency band.

More specifically, for example, in the case of FIG. 1, the terminal 1 can search the macro base station 10 using the second frequency band as a result of performing the base station search operation in the second frequency band, (E.g., PCI) of the macro base station 10 as a result of performing the base station search operation in the second frequency band.

When the identification information (for example, PCI) of the specific base station 10, for example, the above-described macro base station 10, is found as a result of performing the base station search operation in the second frequency band from the terminal 1, And instructs the terminal 1 to acquire detailed information of the base station, that is, the macro base station 10.

At this time, when instructing the terminal 1 to acquire detailed information of the macro base station 10, the controller 130 instructs the terminal 1 to terminate the base station search operation in the second frequency band.

That is, the control unit 130 instructs the terminal 1 to terminate the base station search operation in the second frequency band immediately or immediately after instructing the terminal 1 to acquire the detailed information of the macro base station 10 Thereby terminating the terminal 1 without performing the base station search operation in the two frequency bands.

Then, the terminal 1 terminates the base station search operation in the two frequency bands, acquires detailed information (e.g., EARFCN, ECGI, TAC, PCI, etc.) from the macro base station 10 searched for in the conventional manner, (E.g., EARFCN, ECGI, TAC, PCI, etc.) of the macro base station 10 obtained as a result of acquiring the information to the small base station 100. [

When the detailed information of the macro base station 10 is confirmed from the terminal 1, the control unit 130 controls the macro base station 10 based on the detailed information (e.g., EARFCN, ECGI, TAC, PCI, etc.) (Added) to the neighbor list as a neighbor base station in the second frequency band.

As described above, the base station apparatus 100 according to the present invention allows the terminal using the VoLTE service to search for a base station in a different frequency band at an optimal time, that is, at the time point when the VoLTE service used by the terminal ends, The base station apparatus 100 can effectively increase the success rate of Naver list registration for a neighbor base station (macro base station) using a frequency band different from that of the base station apparatus 100 itself.

Meanwhile, since the present invention is based on a network environment in which macro cells and small cells coexist in the same area, a problem may arise that the quality of the communication service can not be guaranteed as the handover of the terminal becomes too frequent, This problem can be fatal especially for VoLTE services.

For example, as shown in FIG. 1, when the terminal 1 accesses the base station apparatus 100 in the cell C100 and uses the VoLTE service, the terminal 1 moves out of the cell C100, passes through the cell C10, ) Will be described.

In this case, if the base station apparatuses 100 and 200 are conventional small-sized base stations, the terminal 1 performs handover to switch from the base station apparatus 100 to the macro base station 10, The terminal 1 will be handed over from the base station apparatus 100 to the base station apparatus 200 through the macro base station 10 several times by performing handover to switch the connection to the apparatus 200. [

In this situation, the number of handovers according to movement of the terminal 1 increases in a situation where base station apparatuses 10, 100, and 200 of different macrocells and small cells are mixed in the same area, It consumes time to perform operations (e.g., measurement and comparison of signals of neighboring base stations) and results in an increase in the handover failure rate.

2, the base station apparatus 100 according to the present invention may further include a communication service confirmation unit 140, a target base station identification unit 150, and a handover control unit 160 .

The communication service confirmation unit 140 confirms whether or not the communication service used by the terminal 1 is a specific communication service, that is, the aforementioned VoLTE service.

As described above, when the base station apparatus 100 receives a call connection request from the related equipment (e.g., MME) on the network (LTE network) to the terminal 1, And connects the session with the terminal (1).

At this time, if QCI # 1 or QCI # 2 is specified in the call connection request to the terminal 1, the communication service confirmation unit 140 can confirm that the communication service used in the terminal 1 is a VoLTE service.

Accordingly, the viewpoint confirmation unit 120 described above preferably confirms whether or not the communication service currently used by the terminal 1 is a VoLTE service by using the confirmation result of the communication service confirmation unit 140.

The target base station identifying unit 150 identifies the target base station in the neighbor list of the second frequency band when the communication service used by the terminal 1 is the VoLTE service as a result of the confirmation by the communication service checking unit 140. [

As described above, in the present invention, it is assumed that different frequency bands are used between the small base station and the macro base station. Therefore, the macro base station is registered as a neighbor base station in the neighbor list of the second frequency band.

For example, in the case of FIG. 1, the target BS check unit 150 can identify the macro base station 10 using the second frequency band as the target BS in the neighbor list of the second frequency band.

The handover control unit 160 transmits the terminal 1 to the macro base station 10 in the second frequency band when the target base station identification unit 150 confirms that the target base station in the second frequency band, .

That is, the handover control unit 160 handover the terminal 1 to the searched target base station of the second frequency band, for example, the macro base station 10, so that the VoLTE service To be used through the macro base station 10.

If the target base station identification unit 150 determines that the target base station in the second frequency band is not confirmed, the handover control unit 160 receives the terminal 1 as it is and continues to transmit the VoLTE Services.

Therefore, the base station apparatus 100 according to the present invention is configured such that, for the terminal 1 using the VoLTE service, regardless of the handover request from the terminal 1, the target base station (MACRO) The terminal 1 is handed over to the base station 10 and the terminal 1 uses the VoLTE service through the macro base station 10 so that the terminal 1 moves out of the cell C100 and moves to the cell The mobile station C10 will continuously use the VoLTE service through the macro base station 10 without a handover even if the mobile station C10 moves to the cell C200.

As described above, the base station apparatus 100 according to the present invention is capable of reducing the unnecessary handover of the terminal while still ensuring the quality of the communication service used in the terminal in a network environment in which macro cells and small cells coexist .

In addition, the base station apparatus 100, which is a small-sized base station having a small capacity, arbitrarily hands over the terminal 1 using the VoLTE service to the macro base station 10, It is possible to secure radio resources to be allocated and to provide a higher quality data service to a terminal using another terminal, for example, a data service.

Hereinafter, an operation method of a base station apparatus according to a preferred embodiment of the present invention will be described with reference to FIG. 3 and FIG. Hereinafter, the base station apparatus 100 will be described for convenience of explanation.

First, the control flow of the communication system including the base station apparatus 100 according to the present invention will be described with reference to FIG.

When the base station 100 or the small base station 100 according to the present invention receives a call connection request for the terminal 1 from an associated equipment (e.g., MME) on a network (LTE network) (For example, a data service or a VoLTE service) to the terminal 1 by connecting a call session based on a first frequency band, that is, a first frequency band, with the terminal 1 and transmitting / (S10).

Hereinafter, for convenience of description, a case where the VoLTE service is provided to the terminal 1 will be described.

When receiving the E-RAB Release Command message in response to the VoLTE service termination event from the related equipment (e.g., MME) on the network (LTE network), the small base station 100 transmits an RRC Connection Reconfiguration RAB Release Response message to the related equipment (e.g., MME) on the network (LTE network) and then transmits the E-RAB Release Response message to the UE 1 in response to the RRC Connection Reconfiguration Complete message. The VoLTE service termination procedure for the terminal 1 is performed by releasing all the resources allocated to the call session with the terminal 1 for the terminal 1 (S20).

Here, the small base station 100 confirms a specific time point at which the terminal 1 can receive the signal in the second frequency band rather than the current first frequency band (S30).

For example, the small base station 100 may receive the RRC Connection Reconfiguration Complete message from the terminal 1 during the time when the VoLTE service used by the terminal 1 ends, that is, during the VoLTE service termination procedure for the terminal 1 It is possible to confirm that it is a specific time point at which signal reception in the second frequency band other than the current first frequency band is possible.

Accordingly, the small base station 100 measures a signal received from the base station using the second frequency band at a specific point identified as described above, that is, at the time point when the VoLTE service used by the terminal 1 ends, And instructs the terminal 1 to perform an operation of searching for a base station (S40).

The terminal 1 is instructed to perform the base station search operation in the second frequency band from the small base station 100 at the optimal time when the VoLTE service being used through the first frequency band is terminated. The RF module (not shown) capable of receiving signals in the frequency band can be converted into a state capable of receiving signals in the second frequency band and receive signals in the second frequency band. For example, in the case of FIG. 1, the terminal 1 will receive a signal of the macro base station 10 using the second frequency band (S50).

Accordingly, the terminal 1 measures the signal received from the base station using the second frequency band by performing the base station search operation in the second frequency band as in the conventional method, The largest base station) can be searched (S60).

For example, in the case of FIG. 1, the terminal 1 can search the macro base station 10 using the second frequency band as a result of performing the base station search operation in the second frequency band. In this case, (E.g., PCI) of the macro base station 10 as a result of performing the base station search operation of the macro base station 10 (S70).

Hereinafter, an operation method of the base station apparatus according to the preferred embodiment of the present invention will be described in detail with reference to FIGs. 4 and 5. FIG.

The method of operation of the base station 100 according to the present invention is a method in which a call connection request to the terminal 1 is received from an associated equipment (e.g., MME) on a network (LTE network) 5 or QCI # 6, or QCI # 8 or QCI # 9 is designated, a basic call session based on the first frequency band (for example, Default Bearer) is connected to the terminal 1 according to the call connection request, If QCI # 1 or QCI # 2 is specified in the call connection request, in addition to the basic call session based on the first frequency band (for example, Default Bearer) according to the call connection request, Dedicated Bearer) to the terminal 1 to provide a VoLTE service to the terminal 1 (S110).

At this time, the method of operating the base station 100 according to the present invention checks whether the communication service used by the terminal 1 is a specific communication service, that is, a VoLTE service (S120).

For example, when the QCI # 1 or the QCI # 2 is specified in the call connection request to the terminal 1, the base station apparatus 100 according to the present invention operates as a communication service used in the terminal 1 VoLTE service.

In the operation method of the base station apparatus 100 according to the present invention, if the communication service used by the terminal 1 is a VoLTE service (Yes in S120), the target base station is checked in the neighbor list of the second frequency band (S130).

For example, if the macro base station 10 using two frequency bands in the neighbor list of the second frequency band is already registered as a neighbor base station, the operation method of the base station apparatus 100 according to the present invention is a method in which, It is possible to identify the macro base station 10 using the second frequency band as the target base station in the neighbor list of the band.

In this case, the operation method of the base station apparatus 100 according to the present invention handover the terminal 1 to the macro base station 10 in the second frequency band (S135).

That is, the method of operating the base station 100 according to the present invention is a method of operating the terminal 1 by handover to a searched target base station of a second frequency band, for example, the macro base station 10, So that the VoLTE service being used can be used through the macro base station 10.

If it is determined in step S130 that the target base station in the second frequency band is not confirmed (No in step S130), the base station device 100 receives the terminal 1 as it is, To continue to use VoLTE services.

The method of operation of the base station apparatus 100 according to the present invention is a method of receiving a VoLTE service termination event from a related equipment (e.g., MME) on a network (LTE network) while accommodating the terminal 1 and providing a VoLTE service (Step S140), the terminal 1 performs a VoLTE service termination procedure as described above (step S150).

At this time, the method of operation of the base station 100 according to the present invention confirms a specific time point at which the terminal 1 can receive a signal in a second frequency band that is not the current first frequency band (S160).

For example, an operation method of the base station apparatus 100 according to the present invention is a method of operating a VoLTE service from a terminal 1 to an RRC Connection It can be confirmed that the reception of the Reconfiguration Complete message is a specific time at which reception of a signal in the second frequency band other than the current first frequency band is possible.

The operation method of the base station apparatus 100 according to the present invention is a method of operating the base station apparatus 100 in such a manner that a signal received from a base station using the second frequency band at a specific point in time, And instructs the terminal 1 to search for a base station in the second frequency band (S170).

As a result, according to the present invention, the terminal 1 is instructed to perform the base station search operation in the second frequency band from the small base station 100 at the optimal time when the VoLTE service being used through the first frequency band is terminated , And immediately performs the base station search operation in the second frequency band according to this command.

For example, in the case of FIG. 1, the terminal 1 can search the macro base station 10 using the second frequency band as a result of performing the base station search operation in the second frequency band. In this case, (E.g., PCI) of the macro base station 10 as a result of performing the base station search operation of the macro base station 10 to the small base station 100. [

The method of operation of the base station apparatus 100 according to the present invention is a method of detecting the identification information of the specific base station, for example, the above-described macro base station 10 as a result of performing the base station search operation in the second frequency band from the terminal 1 (Step S180 in FIG. 5), the terminal 1 is instructed to acquire the detailed information of the specific base station, that is, the macro base station 10 (S190).

The method of operation of the base station 100 according to the present invention is a method of operating the terminal 1 to terminate the base station search operation in the second frequency band when instructing the terminal 1 to acquire detailed information of the macro base station 10 ).

That is, the method of operation of the base station apparatus 100 according to the present invention is a method of performing the base station search operation in the second frequency band simultaneously with or immediately after instructing the terminal 1 to acquire detailed information of the macro base station 10 (S190), thereby ending the terminal 1 without performing the base station search operation in the two frequency bands.

Then, the terminal 1 terminates the base station search operation in the two frequency bands, acquires detailed information (e.g., EARFCN, ECGI, TAC, PCI, etc.) from the macro base station 10 searched for in the conventional manner, (E.g., EARFCN, ECGI, TAC, PCI, etc.) of the macro base station 10 obtained as a result of acquiring the information to the small base station 100. [

If the detailed information of the macro base station 10 is confirmed from the terminal 1 (Yes in S200), the detailed operation of the macro base station 10 (for example, EARFCN, The macro base station 10 can be registered (added) to the neighbor list as a neighbor base station in the second frequency band based on the ECGI, TAC, PCI, and the like (S230).

If the detailed information of the macro base station 10 is not confirmed from the terminal 1 (S200 No), the method of operation of the base station 100 according to the present invention determines whether the detailed information of the macro base station 10 is received If the number of retry attempts is equal to or less than the predetermined limit number of times (for example, three times) (No at S220), the flow advances to step S190 described above The terminal 1 can be instructed to acquire detailed information of the macro base station 10 again.

As described above, the operation method of the base station apparatus and the base station apparatus according to the present invention can increase the registration (addition) success rate for a neighbor base station (macro base station) using a frequency band different from that of the base station apparatus and the base station apparatus, VoIP, VoLTE, etc.) is arbitrarily handed over to the macro base station, thereby reducing the unnecessary handover of the terminal while still ensuring the quality of the communication service.

The method of operation of the base station apparatus according to an embodiment of the present invention may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, 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 skilled 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.

According to the operation method of the base station apparatus and the base station apparatus according to the present invention, it is possible to increase the registration success rate of a neighbor base station (macro base station) using a different frequency band and to use a specific communication service (VoIP, VoLTE, etc.) The handover to the macro base station is arbitrarily handed over to the mobile station so that the quality of the communication service is still assured while unnecessary handover of the mobile station can be reduced. Therefore, It is not only a possibility that the device is commercially available or operable, but it is an industrially applicable invention since it is practically possible to carry out clearly.

1: terminal 100, 200: (small) base station apparatus
10: (macro) base station device

Claims (12)

A signal transmitting and receiving unit transmitting and receiving signals to and from the terminal through a specific frequency band and using the communication service according to the signal transmission and reception at the terminal;
A point-in-time confirmation unit for confirming a specific point of time when the terminal can receive signals in a frequency band other than the specific frequency band; And
And a controller for instructing the terminal to perform a search for a base station in another frequency band by measuring a signal received from the base station using the other frequency band at the specific time,
The specific point in time is,
And when the communication service used by the terminal is a specific communication service, the communication service is terminated. delete The method according to claim 1,
The specific communication service includes:
Wherein the base station apparatus is a communication service requiring a service quality guarantee of a certain level or higher. The method according to claim 1,
Wherein,
Wherein the terminal registers the specific base station found as a result of performing the base station search operation in the other frequency band in the neighbor list as a neighbor base station in the other frequency band. The method according to claim 1,
Wherein,
When a specific base station found as a result of performing a base station search operation in the other frequency band from the terminal is identified, instructs the terminal to acquire detailed information of the specific base station,
And registers the specific base station in the neighbor list as a neighbor base station in the other frequency band based on the detailed information of the specific base station when detailed information of the specific base station is confirmed from the terminal. 6. The method of claim 5,
Wherein,
And instructs the terminal to terminate the base station search operation in the other frequency band when instructing the terminal to acquire detailed information of the specific base station. 5. The method of claim 4,
A communication service checking unit for checking whether the communication service used by the terminal is a specific communication service;
A target base station identification unit for identifying the target base station in the other frequency band from the neighbor list if the communication service is the specific communication service; And
And a handover controller for performing handover to the target base station of the other frequency band when the target base station of the other frequency band is confirmed. 8. The method of claim 7,
The specific communication service includes:
Wherein the base station apparatus is a communication service requiring a service quality guarantee of a certain level or higher. Transmitting and receiving a signal to and from a terminal over a specific frequency band and using the communication service according to the signal transmission and reception at the terminal;
Confirming a specific time point at which the terminal can receive signals in a frequency band other than the specific frequency band; And
Measuring a signal received from the base station using the other frequency band at the specific time point and instructing the terminal to search for the base station of the other frequency band,
The specific point in time is,
And when the communication service used by the terminal is a specific communication service, the communication service is terminated. delete 10. The method of claim 9,
Further comprising the step of registering, as a neighbor list in a neighboring frequency band, a specific base station found as a result of performing a base station search operation of the other frequency band in the terminal. 12. The method of claim 11,
Determining whether the communication service used by the terminal is a specific communication service;
Confirming the target base station of the other frequency band from the neighbor list if the communication service is the specific communication service; And
Further comprising the step of performing a handover to the target base station of the other frequency band when the target base station of the other frequency band is identified.

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