KR20140144968A - Base station apparatus and control method thereof - Google Patents

Abstract

The present invention discloses a base station apparatus and a method of operating the same. According to the present invention, a small-sized base station arbitrarily handovers a terminal using a communication service such as a VoIP, VoLTE, etc. to a macro base station in a situation where various base stations coexist, so that the quality of the communication service is guaranteed while reducing unnecessary handovers of the terminal.

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 an operation method of the base station apparatus, and more particularly, to a mobile station in which a small base station uses communication services such as VoIP and VoLTE in a situation where various base stations are mixed in the same area, To an operation method of a base station apparatus and a base station apparatus capable of reducing unnecessary handover of a mobile station while ensuring the quality of a communication service.

In recent LTE networks, heterogeneous network technologies have been emerging that allocate base stations with different cell sizes in the same area to increase the frequency utilization rate. In a heterogeneous network environment, various types of small base stations having a smaller coverage other than a general macro base station are arranged, so that various types of base stations form coverage in an overlapped area and provide a wireless communication service to a user.

In general, a terminal using a communication service through a base station provides a handover request to a serving base station when a situation requiring handover is detected, and the serving base station searches for a target base station satisfying a handover condition to the terminal Search control information to be transmitted.

Accordingly, the terminal measures the signal strength of the neighbor base station based on the search control information, searches for a target base station satisfying the handover condition based on the signal strength, and performs a handover to switch access to another base station.

However, in the heterogeneous network environment as described above, as the user moves, the UE will frequently measure the signal of the neighboring base station of a higher strength than the signal of the serving base station, and the number of times of handover of the UE is unnecessarily increased .

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

However, in a heterogeneous network environment such as the above-mentioned case, the handover of the terminal becomes so frequent that the quality of communication services such as VoIP and VoLTE may not be guaranteed.

Therefore, according to the present invention, it is possible to reduce the unnecessary handover of the terminal, while still ensuring the quality of the communication service, for the terminal using the communication service such as VoIP and VoLTE through the base station in a situation where various base stations are mixed in the same area I would like to propose a plan.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a small base station that handover a terminal using a communication service such as VoIP or VoLTE to a macro base station, And to reduce the unnecessary handover of the terminal while guaranteeing the operation of the base station apparatus and the base station apparatus.

According to a first aspect of the present invention, there is provided a base station apparatus including: a call connection request confirmation unit for checking whether a call connection request to a terminal is related to a specific communication service; If the call connection request is related to the specific communication service, searching for a target base station using a frequency band different from that of the currently connected base station during a search time set in association with the terminal Command section; And a handover controller for performing a handover to the searched target BS when the MS searches for the target BS in the search result of the target BS in the MS.

Preferably, the search command unit changes the search time when the terminal fails to search for the target base station, and searches for a frequency band different from the currently connected base station apparatus during the changed search time It is possible to re-search the target base station to be used.

Preferably, the search command unit may change the search time associated with the terminal to increase as the number of times that the terminal fails to search the target base station increases.

Preferably, when the other base station according to the search result is not included in the pre-registered neighbor list, it is determined that the terminal has failed to search for the target base station. Based on the history information related to the search result, And a Naver list control unit for adding the other base station to the Naver list if it is determined that the search has been performed more than a predetermined number of times.

Preferably, the call connection request confirmation unit may determine that the call connection request is related to the specific communication service if a call quality request identifier is specified in the call connection request.

Preferably, the specific communication service may be a communication service requiring a service quality guarantee of a certain level or more.

According to a second aspect of the present invention, there is provided a method of operating a base station, the method comprising: a call connection request checking step of determining whether a call connection request for a terminal is related to a specific communication service; If the call connection request is related to the specific communication service, searching for a target base station using a frequency band different from that of the currently connected base station during a search time set in association with the terminal Command step; And a handover control step of handing over the terminal to the searched target base station when the terminal searches for the target base station when the terminal searches for the target base station in the terminal.

Preferably, the search command step may include a step of changing the search time when the terminal fails to search for the target base station and searching for a frequency band different from the currently connected base station apparatus during the changed search time, To re-search the target base station using the base station.

Advantageously, the search command step may be modified to increase the search time associated with the terminal as the number of unsuccessful attempts by the terminal to search for the target base station increases.

Preferably, the call connection request checking step may be performed when the call connection request is associated with the specific communication service if a call quality request identifier is specified in the call connection request.

According to the operation method of the base station apparatus and the base station apparatus of the present invention, it is possible to reduce unnecessary handover of the terminal while ensuring the quality of the VoLTE service in a situation where various base station apparatuses having different cell coverage are mixed in the same area By reducing the number of times of handover as described above, it is possible to reduce the time spent by the mobile station for handover (e.g., measuring and comparing signals of neighboring base stations) and reducing the handover failure rate.

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 is a flowchart illustrating an operation method of a base station apparatus according to an exemplary 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 10 that wants to use a communication service with a counterpart device (not shown) based on a specific network, and a terminal 10 that transmits and receives data between the terminal 10 and a counterpart device (100, 100 ', 100 ", 200) supporting the use of the communication service in the terminal (10).

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 100, 100 ', 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 apparatus 100, 100 ', 100 "may be a small base station, and the base station apparatus 200 may be a macro base station. The cell coverage 1, 1 ', 1 "of the base station apparatus 200, which is a macro base station, can be included in the cell coverage 2 of the base station apparatus 200. [

Since the cell coverage (1,1 ', 1 ") of the base station apparatuses 100, 100', 100" which are small base stations belongs to the cell coverage 2 of the base station apparatus 200 as a macro base station, ) And the base station apparatus 100, 100 ', 100 "are used in the same frequency band, the terminal 10 is connected to the base station apparatus 200 and the base station apparatus 100, 100' in the boundary area of the cell coverage 1, 1 ', 1" Pinging may occur between the base station apparatus 100 and the base station apparatus 100 and the signals of the base station apparatuses 100, 100 ', 100 " , 1 ', 1 ") may degrade the signal quality.

Accordingly, it is preferable to use different frequency bands between the base station apparatus 200 and the base station apparatuses 100, 100 ', 100 "belonging to the cell coverage 2 of the base station apparatus 200. For example, The base station apparatus 100, 100 ', 100 "may use a frequency band of 1.8 GHz and the base station apparatus 200 which is a macro base station may use a frequency band of 800 MHz.

As described above, the present invention is based on the situation where various base station apparatuses 100, 100 ', 100 ", 200 having different cell coverage are mixed in the same area, and the base station apparatus according to the present invention is preferably a small base station.

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

For example, when describing a data service, the terminal 10 accesses a specific network (LTE network) through the base station apparatuses 100, 100 ', 100 " The data service can be used by transmitting / receiving data to / from a data service device (not shown) that provides a service (e.g., service, SNS service, and portal service).

The terminal 10 is connected to a specific network (LTE network) through the base station apparatuses 100, 100 ', 100 ", and 200 to communicate with a counterpart terminal (not shown) of the VoLTE service. And the VoLTE data is transmitted and received, the VoLTE service can be used.

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

The terminal 10 is located in the cell coverage 1 of the base station apparatus 100 and is connected to the base station apparatus 100 in a state where the terminal 10 is connected to the base station apparatus 100 And the base station apparatus according to the present invention is connected to the base station apparatus 100, 100 ', 100 "which is a small base station, and the base station apparatus 100 will be described as a representative.

The base station apparatus 100 according to the present invention performs a call connection procedure when a call connection request for the connected terminal 10 is received and connects the call session according to the call connection request with the terminal 10, ) Enables communication services (e.g., data services or VoLTE services) to be used over call sessions.

On the other hand, the base station apparatus 100 confirms whether a call connection request to the connected terminal 10 is associated with a specific communication service.

Here, the specific communication service may be, for example, the aforementioned VoLTE service as a communication service requiring a service quality guarantee of a certain level or higher.

In other words, when the base station device 100 receives a call connection request for the terminal 10 from an associated device (e.g., MME), the base station device 100 performs a call connection procedure to transmit a call session, And confirms whether a call connection request to the terminal 10 is related to a specific communication service, that is, a VoLTE service.

If it is determined that the call connection request to the terminal 10 is related to the specific communication service, that is, the VoLTE service, the base station apparatus 100 determines that the terminal 10 is currently connected And searches for a target base station using a frequency band different from that of the base station apparatus 100. [

More specifically, in the process of connecting the terminal 10 to the base station apparatus 100, the base station apparatus 100 instructs the terminal 10 to designate a frequency band to be handed over at the time of handover Information. For example, if the base station apparatus 100 uses 1.8 GHz as described above, the base station apparatus 100 can provide the terminal 10 with designation information for designating another frequency band, that is, 800 MHz.

The terminal 10 is provided with the designation information by the base station apparatus 100 and the terminal 10 stores the designation information based on the designation information during the search time in accordance with the search instruction from the base station apparatus 100 (For example, 800 MHz) different from that of the currently connected base station apparatus 100, and then provides the search result to the base station apparatus 100 .

1, in order to avoid a handover ping-pong phenomenon and a signal quality deterioration phenomenon in the boundary region of the cell coverage (1, 1 ', 1 "), The terminal 10 uses the different frequency bands between the devices 100, 100 ', 100 ", so that the terminal 10 can transmit the base station apparatus 200 as a target base station that provides a specific communication service using a frequency band different from that of the base station apparatus 100, .

The base station apparatus 100 performs handover to the searched target base station such as the base station apparatus 200 when it is determined that the terminal 10 successfully searches for the target base station based on the search result provided by the terminal 10 So that the terminal 10 can receive a specific communication service through the base station 200.

In the conventional base station apparatus, after the terminal detects a situation requiring handover, the terminal requests the handover and only the terminal searches for the target base station.

For example, a description will be given of a case where a user of the terminal 10 moves from the cell coverage 1 to the cell coverage 1 'through the cell coverage 1' while using the VoLTE service through the base station apparatus 100 .

In this case, if the base station apparatus 100, 100 ', 100 "is a conventional small base station, the terminal 10 continuously measures the signal for the neighbor base station and enters the cell coverage 1' When a handover necessity situation in which the signal strength of the base station apparatus 100 'is greater than the signal strength of the currently connected base station apparatus 100 is requested, the handover request is transmitted to the base station apparatus 100' Handover in which the signal strength of the base station apparatus 100 "is greater than the signal strength of the currently connected base station apparatus 100 'while entering the cell coverage 1" in the cell coverage 1' The terminal 10 transmits a handover request to the base station apparatus 100 'and performs handover to switch the connection to the base station apparatus 100' To the base station apparatus 100 " will be.

In a situation where various base station apparatuses 100, 100 ', 100 ", 200 having different cell coverage are mixed in the same area, the number of handovers according to movement of the terminal 10 increases, (E.g., measuring and comparing signals of neighboring base stations) for the handover and also increasing the handover failure rate.

Particularly, if the terminal 10 is using a VoLTE service that should guarantee a certain level of quality or more, it may happen that the VoLTE service quality can not be guaranteed due to the frequent handover of the terminal 10.

However, the base station apparatus 100 according to the present invention may be configured such that the terminal 10 using the specific communication service, that is, the VoLTE service, is arbitrarily selected by the terminal 10 from the terminal 10 regardless of the handover request from the terminal 10. [ The terminal 10 performs handover to the base station apparatus 200 which is a macro base station by allowing the terminal 10 to search for the base station so that the terminal 10 uses the VoLTE service through the base station apparatus 200. Thus, ) To the cell coverage 1 '' through the cell coverage 1 ', the VoLTE service will be continuously used through the base station 200 without handover.

Meanwhile, if the base station apparatus 100, which provides a communication service (e.g., a VoLTE service or a data service) to a plurality of terminals including the terminal 10 using 1.8 GHz, The base station apparatus 100 can not use 1.8 GHz during the search, so that the base station apparatus 100 can not use 1.8 GHz for the communication being used by all of the terminals including the terminal 10 connected to the base station apparatus 100 Services (such as VoLTE services or data services) will be disconnected.

Therefore, the base station apparatus 100 of the present invention does not directly search for the target base station to which the terminal 10 using the specific communication service is to be handed over, but instead transmits the terminal 10 a frequency band different from that of the base station apparatus 100 To search for a target base station using the base station.

Of course, since the terminal 10 can not use 1.8 GHz during the search time for searching for the target base station by measuring the signal strength of another base station using a frequency band different from that of the base station 100, i.e., 800 MHz, The specific communication service being used during the search time will be disconnected.

In order to minimize the disconnection phenomenon of the specific communication service of the terminal 10, which occurs because the target base station of the frequency band (for example, 800 MHz) other than the frequency band (for example, 1.8 GHz) The scheme will be described in detail with reference to FIG. 2 below.

As described above, the base station apparatus 100 according to the present invention is able to guarantee the quality of the VoLTE service while ensuring the quality of the VoLTE service in a situation where various base station apparatuses 100, 100 ', 100 & It is possible to reduce unnecessary handover of the base station 10 and reduce the number of times of handover in this manner, thereby reducing the time consumed by the terminal 10 in the operation for handover (for example, measurement and comparison of signals of peripheral base stations) It is possible to derive the additional effect of lowering.

In addition, the base station apparatus 100, which is a small-sized base station having a small capacity, voluntarily hands over the terminal 10 using the VoLTE service to the base station apparatus 200, which is a macro base station, It is possible to secure the radio resources to be allocated for the service, and it is possible to expect a higher quality data service to be provided to a terminal using another terminal, for example, a data service.

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 reference number of the base station apparatus 100 will be described for convenience of explanation.

The base station apparatus 100 according to the present invention includes a call connection request confirmation unit 110 for checking whether a call connection request to the terminal 10 is related to a specific communication service, A search command unit (not shown) for instructing the terminal 10 to search for a target base station using a frequency band different from that of the currently connected base station device 100 during a search time set in association with the terminal 10 And a handover controller 130 for handover the terminal 10 to the searched target base station if the search result terminal 10 searching for the target base station in the terminal 10 succeeds in searching for the target base station .

The call connection request confirmation unit 110 checks whether a call connection request to the terminal 10 connected to the base station device 100 is related to a specific communication service.

Here, the specific communication service may be, for example, the aforementioned VoLTE service as a communication service requiring a service quality guarantee of a certain level or higher.

Accordingly, the call connection request confirmation unit 110 can confirm whether a call connection request to the terminal 10 is related to the VoLTE service.

More specifically, the call connection request confirmation unit 110 can confirm that a call connection request is associated with the VoLTE service if a specific quality of service separator is specified in the call connection request to the terminal 10 .

For example, the terminal 10 may be a calling party attempting a VoLTE service by a partner apparatus (not shown) or a called party receiving a VoLTE service attempted from a partner apparatus (not shown).

As described above, when the terminal 10 accepts an incoming call of the VoLTE service attempted by the terminal 10 (not shown) or the incoming call of the VoLTE service attempted from the other terminal (not shown) (E.g., MME) of the specific network (LTE network) recognizing the call accepts a call connection request to connect the call session for VoLTE data transmission / reception of the VoLTE service to the terminal 10, ) To the connected base station apparatus 100 and transmits a call connection request for requesting the other party apparatus (not shown) to connect a call session for VoLTE data transmission / reception of VoLTE service to the base station Device (not shown).

In addition, when the terminal 10 tries to use a general data service, the related equipment (e.g., MME) of the specific network (LTE network) that recognizes the data service requests the terminal 10 to send a call session To the base station apparatus 100 to which the terminal 10 is connected.

Upon receiving a call connection request from the related equipment (e.g., MME) to the terminal 10, the base station apparatus 100 performs a call connection procedure to connect a call session based on the call connection request to the terminal 10 So that the terminal 10 can use a communication service (for example, a data service or a VoLTE service).

Here, a call connection request (e.g., an E-RAB Setup Request) to the terminal 10 provided from the related equipment (e.g., MME) includes a service quality identifier (QCI) : QoS Class Indicator) is specified.

For example, a call connection request for 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 for ensuring quality of service suitable for use of the data service.

When a call connection request for the terminal 10 is received from the related equipment (e.g., MME) to the base station device 100, the call connection request confirmation unit 110 transmits a call connection request to the QCI # 1 < / RTI > or QCI # 2 is specified, whether the call connection request is associated with a VoLTE service.

That is, if QCI # 1 or QCI # 2 is specified in the call connection request to the terminal 10, the call connection request confirmation unit 110 will confirm that the call connection request is related to the VoLTE service.

If the call connection request to the terminal 10 is related to the specific communication service as a result of the confirmation of the call connection request confirmation unit 110, the search command unit 120 transmits the call connection request to the terminal 10 to search for a target base station using a frequency band different from that of the currently connected base station device 100. [

Accordingly, the terminal 10 determines whether or not the other base station 100 uses a frequency band (for example, 800 MHz) different from that of the base station apparatus 100 based on the above-described designation information during a search time in accordance with a search command from the base station apparatus 100 The base station apparatus 100 determines whether there is a target base station, and provides the base station apparatus 100 with the search result.

At this time, the terminal 10, which has used the specific communication service through the base station device 100 using 1.8 GHz as described above, searches for a signal strength of another base station using a frequency band different from that of the base station device 100, Since 1.8 GHz is not available during the time, the specific communication service being used will be disconnected during the search time.

Hereinafter, an embodiment of a method for minimizing the disruption of a specific communication service of the terminal 10 in the base station apparatus 100 according to the present invention will be described in detail.

When the call connection request for the terminal 10 is related to the specific communication service as a result of the confirmation of the call connection request confirmation unit 110, And instructs the terminal 10 to search for a target base station using a frequency band different from that of the currently connected base station device 100. [

That is, the search command unit 120 sets a search time (e.g., gapOFFset) related to the terminal 10 when a call connection request to the terminal 10 is related to a specific communication service, T to the terminal 10 by providing a search command including the search time to the terminal 10 so as to instruct the terminal 10 to search for the target base station during the search time according to the search command.

At this time, the search instruction unit 120 preferably sets the initial search time set in relation to the terminal 10 to be the shortest. Hereinafter, the first search time will be referred to as a search time 1.

Accordingly, the terminal 10 searches for a target base station using a different frequency band (for example, 800 MHz) from the base station apparatus 100 during the search time 1 according to the search command from the base station apparatus 100 as described above, And provide the search result to the base station apparatus 100. [

More preferably, the terminal 10 is connected to another peripheral base station using a frequency band (for example, 800 MHz) different from that of the base station apparatus 100 during a search time 1 according to a search command from the base station apparatus 100 It is possible to detect whether there is a target base station satisfying the handover condition and to provide the search result to the base station apparatus 100. [

For example, based on the result of measuring the signal strength of a nearby base station using a frequency band (for example, 800 MHz) different from that of the base station apparatus 100, the terminal 10 calculates a signal strength The base station can be searched as a target base station satisfying the handover condition.

The search command unit 120 determines whether or not the terminal 10 has failed to search for the target base station based on the search result obtained by searching the target base station at the terminal 10.

More specifically, the search instruction unit 120 determines that the search result is not received so that the specific reception waiting time T elapses from the terminal 10, or the information contained in the search result is not valid, It can be determined that the terminal 10 fails to search for the target base station.

That is, if the search result is not received from the terminal 10 so that the specific reception waiting time T elapses based on the timer operated as described above, the search command unit 120 searches the target base station It is judged to have failed.

The search command unit 120 determines whether the information included in the search result is valid even if the search result is received from the terminal 10 before the specific reception waiting time T elapses It is determined that the terminal 10 fails the target base station search. At this time, the search result may include identification information (e.g., PCI) of another base station (e.g., base station 200) retrieved from the terminal 10, a signal strength value, and the like. Accordingly, the search instruction unit 120 can confirm that the information is not valid if the search result does not include the identification information (e.g., PCI) and the signal strength value satisfying the normal specification.

Even if the information included in the search result is confirmed to be valid, the search command unit 120 determines that the other base station, that is, the base station 200 according to the search result is not included in the neighbor list registered in the base station 100 , It is determined that the terminal 10 has failed the target base station search.

At this time, if the search command unit 120 determines that the other base station, that is, the base station 200 according to the search result as a result of the determination based on the history information described later, has been retrieved for a predetermined number of times or more, It is preferable to judge that it is failed.

On the other hand, the search command unit 120 receives the search result from the terminal 10 before the specific reception waiting time T elapses, the information included in the search result is valid, If the device 200 is included in the neighbor list, it can be determined that the terminal 10 has succeeded in searching for the target base station.

The handover controller 130 handover the terminal 10 to the searched target base station when the search result terminal 10 that has searched for the target base station in the terminal 10 succeeds in searching for the target base station.

That is, when it is determined that the terminal 10 has succeeded in searching for the target base station as a result of the determination by the search command unit 120, the handover controller 130 performs handover to the target base station, And allows the terminal 10 to use the specific communication service, that is, the VoLTE service, which the terminal 10 is using through the base station apparatus 100, through the base station apparatus 200.

Meanwhile, if it is determined that the search result terminal 10 has failed to search the target base station, the search command unit 120 may change the search time and transmit the changed search time to the currently connected base station apparatus 100 to search for a target base station using a different frequency band.

At this time, the search command unit 120 preferably changes and sets the search time associated with the terminal 10 to become longer as the number of times that the terminal 10 fails to search for the target base station increases.

That is, the search command unit 120 changes and sets the search time set in relation to the terminal 10 if the terminal 10 fails to search the target base station based on the determination result, and at this time, the terminal 10 ), The search time is changed so as to be longer than the search time 1 set immediately before. Hereinafter, it is assumed that the search time 2 is set to be longer than the search time 1.

The search command unit 120 operates a timer for counting a specific reception wait time T and transmits a search command including a search time to the terminal 10 ) So that the terminal 10 can instruct the target base station to search again for the search time 2 according to the search command.

Accordingly, the terminal 10 uses a frequency band (e.g., 800 MHz) different from that of the base station apparatus 100 for a search time 2 according to a search command from the base station apparatus 100 as described above, Searches for a base station, and provides the search result to the base station apparatus 100.

Accordingly, the search command unit 120 will determine whether the terminal 10 has failed the target base station search, based on the search result obtained by searching the target base station in the terminal 10 as described above.

The search command unit 120 changes and sets the search time set with respect to the terminal 10 if the terminal 10 fails to search for the target base station based on the determination result, Since the target base station search fails in the target base station, the search time 3 is set to be longer than the search time 2 set immediately before.

Here, the search command unit 120 may be configured to change the search time so that the search time is increased by a certain value each time the target base station search fails, or may be changed so that the search time becomes longer as the number of failures increases , The search time may be set to be longer by a value set by the operator irrespective of the number of failures.

As described above, since the terminal 10 can not use 1.8 GHz during the search time for measuring the signal strength of the other base station using the frequency band different from that of the base station 100, that is, 800 MHz, the terminal 10 can not use the communication service Eg VoLTE service) will be disconnected.

In this case, if the search time is short, the time for disconnection of the communication service can be shortened. Instead, the accuracy of the search result may be reduced and the handover success rate may be lowered. On the other hand, But the communication service may be disconnected for a long time.

In consideration of this situation, the base station apparatus 100 of the present invention first searches for a target base station in a different frequency band with respect to the terminal 10 to be searched for a target base station for inter-frequency band handover It is possible to minimize the communication service disconnection time of the terminal 10 and to further re-search the target base station of the other frequency band in the terminal 10 every time the target base station search fails to improve the accuracy of the search result Thereby increasing the handover success rate.

Furthermore, the base station apparatus 100 of the present invention may further include a neighbor list control unit 140.

When the other base station (for example, base station device 200) according to the search result of searching for the target base station in the terminal 10 is not included in the Naver list, the Naver list control section 140 generates history information related to the search result (E.g., the base station apparatus 200) to the neighbor list when it is determined that the other base station (e.g., the base station apparatus 200) has been searched for more than a preset number of times.

More specifically, the search command unit 120 confirms that the other base station, for example, the base station apparatus 200 according to the search result is not included in the neighbor list registered in the base station apparatus 100, It is possible to increase the number of searches performed by the base station apparatus 200 by one and store the same in the history information.

Therefore, in the base station apparatus 100, when a base station not included in the neighbor list is searched by the terminal, the base station apparatus 100 manages the history information while increasing the search frequency of the base station by one.

When the other base station (e.g., the base station 200) corresponding to the search result of searching for the target base station in the terminal 10 is not included in the neighbor list, the Naver list control unit 140 updates the history The base station apparatus 200 can be added to the neighbor list if it is determined that the number of searches of the base station apparatus 200 is increased by one and the base station apparatus 200 is searched for more than a predetermined number of times based on the history information .

At this time, the Naver list control unit 140 can add the base station apparatus 200 to the Naver list after the terminal 10 has finished using the specific communication service, that is, the VoLTE service that the terminal 10 is using through the base station apparatus 100 .

After the base station 200 is added to the neighbor list, if the base station 200 is included in the search result of searching for the target base station in the terminal 10, the base station 200 is included in the neighbor list The base station apparatus 100 will make a handover to the base station apparatus 200 when the terminal 10 searches for the target base station 200 as a target base station.

Therefore, the base station apparatus 100 according to the present invention can reduce unnecessary handover of the terminal while ensuring the quality of the VoLTE service in a situation where various base station apparatuses having different cell coverage are mixed in the same area, By reducing the number of handovers, it is possible to reduce the time spent by the terminal for handover operations (e.g., measuring and comparing signals from neighboring base stations) and by reducing the handover failure rate.

Further, in deriving the above-mentioned effect, the base station apparatus 100 according to the present invention further increases the handover success rate while minimizing communication service disconnection during a search time consumed for searching for a target base station in a different frequency band The effect can be obtained.

Hereinafter, an operation method of the base station apparatus according to the 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 terminal 10 is connected to the base station 100, the base station 100 transmits a call connection request to the terminal 10 from an associated device (e.g., MME) of a specific network (LTE network) When the call connection request is received (S20), a call connection procedure is performed according to a call connection request to the terminal 10 to connect a call session according to the call connection request to the terminal 10, (E.g., data service or VoLTE service) (S30).

Meanwhile, the base station apparatus 100 determines whether a call connection request to the terminal 10 received as described above is related to a specific communication service, for example, a VoLTE service (S40).

If it is determined in step S40 that the call connection request to the terminal 10 is related to the specific communication service, that is, the VoLTE service, the base station apparatus 100 determines the search time (for example, The mobile station 10 is instructed to search for a target base station using a frequency band different from that of the currently connected base station device 100 during a search time 1 (S50).

At this time, the base station apparatus 100 may perform the above-described steps S40 and S50 at the same time or at substantially the same time while performing the above-described step S30.

The terminal 10 is provided with the designation information by the base station apparatus 100 and the terminal 10 stores the designation information on the basis of the above-mentioned designation information during the search time 1 according to the search instruction from the base station apparatus 100 The base station device 100 measures the signal strength of a nearby base station using a frequency band different from that of the base station device 100 (for example, 800 MHz) to search for a target base station (S60), and provides the search result to the base station device 100 (S65).

The base station apparatus 100 determines whether or not the terminal 10 has failed in the target base station search based on the search result provided from the terminal 10 as described above, that is, the search result obtained by searching the target base station in the terminal 10 .

For example, when the base station apparatus 100 determines that the target base station search fails (S70), the base station apparatus 100 changes and sets the search time 1 set with respect to the terminal 10, The target base station is searched again during a search time (e.g., search time 2) (S90).

At this time, it is preferable that the base station apparatus 100 changes the search time associated with the terminal 10 to be longer as the number of times that the terminal 10 fails to search for the target base station increases. That is, the search time 2 is longer than the search time 1 described above.

The terminal 10 then searches for a neighboring area using a different frequency band (for example, 800 MHz) from the base station apparatus 100 based on the above-described designation information during a search time 2 according to a search command from the base station apparatus 100 The signal strength of the base station is measured to find whether there is a target base station (S100), and the search result is provided to the base station device 100 (S105).

The base station apparatus 100 determines whether or not the terminal 10 has failed in the target base station search based on the search result provided from the terminal 10 as described above, that is, the search result obtained by searching the target base station in the terminal 10 .

For example, the base station apparatus 100 handover the terminal 10 to the searched target base station, for example, the base station apparatus 200 (S120) when it determines that the terminal 10 succeeds in searching for the target base station (S110).

That is, when it is determined that the terminal 10 has succeeded in searching for the target base station, the base station apparatus 100 handover the terminal 10 to the searched target base station such as the base station apparatus 200 (S120) (VoLTE) service through the base station apparatus 100 through the base station apparatus 200 (S130).

At this time, the base station apparatus 100 connects the call session according to the call connection request with the terminal 10 as in the above-described step S30, so that the terminal 10 transmits a communication service (for example, a data service or a VoLTE service) The time for which the terminal 10 is handed over to the target base station, for example, the base station 200 through the steps S40 to S120 described above is very short, It will not be noticed that the base station apparatus 100 is handed over to the base station apparatus 200 through the above-described process.

As described above, the base station apparatus 100 according to the present invention is able to arbitrarily transmit the terminal 10 using the specific communication service, that is, the VoLTE service, regardless of the handover request from the terminal 10 10, it is possible to reduce the unnecessary handover of the terminal 10 while ensuring the quality of the VoLTE service by performing the handover to the base station 200 as the macro base station.

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

The method of operation of the base station apparatus 100 according to the present invention is a method in which when a call connection request for the terminal 10 is received in step S200 while the terminal 10 is connected to the terminal 10 in step S210, (E.g., data service or VoLTE service) to the terminal 10 by connecting the call session according to the call connection request to the terminal 10 by performing a call connection procedure (S220).

The method of operation of the base station 100 according to the present invention is a method of determining whether a call connection request to the terminal 10 is related to a specific communication service (S230).

Here, the specific communication service may be, for example, the aforementioned VoLTE service as a communication service requiring a service quality guarantee of a certain level or higher.

More specifically, the method of operation of the base station apparatus 100 according to the present invention is characterized in that when receiving a call connection request for the terminal 10 from an associated equipment (e.g., MME) That is, whether QCI # 1 or QCI # 2 is specified, whether the call connection request is associated with a VoLTE service.

That is, when QCI # 1 or QCI # 2 is specified in the call connection request to the terminal 10, the base station apparatus 100 according to the present invention determines that the call connection request is related to the VoLTE service .

If the QCI # 1 or QCI # 2 is specified in the call connection request to the terminal 10, the base station apparatus 100 determines that the call connection request is related to the VoLTE service S230 Yes), the mobile station 10 is instructed to search for a target base station using a frequency band different from that of the currently connected base station device 100 during a search time set in association with the terminal 10 (S240).

That is, the operation method of the base station apparatus 100 according to the present invention sets a search time (e.g., gapOFFset) related to the terminal 10 when a call connection request to the terminal 10 is related to a specific communication service A timer for counting a specific reception waiting time T is provided and a search command including a search time is provided to the terminal 10 so that the terminal 10 can access the currently connected base station 100 To search for a target base station using a different frequency band than the target base station.

At this time, it is preferable that the operation method of the base station apparatus 100 according to the present invention sets the initial search time set with respect to the terminal 10 to be the shortest. Hereinafter, the first search time will be referred to as a search time 1.

Accordingly, the terminal 10 uses a frequency band (e.g., 800 MHz) different from that of the base station apparatus 100 for the search time 1 according to the search command from the base station apparatus 100 as described above, Searches for a base station, and provides the search result to the base station apparatus 100.

The method of operation of the base station apparatus 100 according to the present invention determines whether or not the terminal 10 fails to search for a target base station based on a search result obtained by searching the target base station in the terminal 10.

More specifically, if the search result is not received from the terminal 10 so that the specific reception waiting time T elapses based on the timer operated as described above (S250 No), it is determined that the terminal 10 fails to search for the target base station.

The operation method of the base station apparatus 100 according to the present invention is such that even if the search result is received from the terminal 10 before the specific reception waiting time T elapses (S250 Yes) (S255 No), it is determined that the terminal 10 has failed to search for the target base station.

In the operation method of the base station apparatus 100 according to the present invention, even if it is confirmed that the information included in the search result is valid (Yes at S255), the other base station apparatus 200, (S257 No), it is determined that the terminal 10 has failed to search for the target base station.

On the other hand, the operation method of the base station apparatus 100 according to the present invention is such that the search result is received from the terminal 10 before the specific reception waiting time T elapses, the information contained in the search result is valid, (S257 Yes), it can be determined that the target base station 200 has succeeded in searching for the target base station.

The method of operation of the base station apparatus 100 according to the present invention can be applied to a case where the terminal 10 successfully searches for a target base station (e.g., the base station apparatus 200) (S260) so that the terminal 10 can use the specific communication service that is being used by the base station apparatus 100, that is, the VoLTE service, through the base station apparatus 200 (S260).

Meanwhile, the operation method of the base station apparatus 100 according to the present invention is configured such that when it is determined that the target base station search has failed in the terminal 10 as in S250 No, S255 No, and S257 No, The terminal 10 re-searches for a target base station using a frequency band different from that of the base station 100 to which the terminal 10 is currently connected during the changed search time.

In this case, it is preferable that the operation method of the base station apparatus 100 according to the present invention is changed so that the search time associated with the terminal 10 becomes longer as the number of times that the terminal 10 fails to search for the target base station increases.

That is, the operation method of the base station apparatus 100 according to the present invention changes the search time set in relation to the terminal 10 if the terminal 10 fails to search for the target base station, The search time is changed and set so as to be longer than the search time 1 set immediately before. Hereinafter, it is assumed that the search time 2 is set to be longer than the search time 1.

More specifically, the operation method of the base station apparatus 100 according to the present invention determines whether the terminal 10 fails to search for another base station apparatus in steps S250 No, S255 No, and S257 No, The search time 1 set in relation to the search time 2 is changed to the longer search time 2 and the number of re-searching is increased by one (S270).

The operation method of the base station apparatus 100 according to the present invention is such that if the number of reselections does not exceed the predetermined limit number (S275 Yes), the method returns to step S240 to count a timer for counting a specific waiting time T And instructs the terminal 10 to search the target base station for the search time 2 by searching for the target base station.

Accordingly, the terminal 10 uses a frequency band (e.g., 800 MHz) different from that of the base station apparatus 100 for a search time 2 according to a search command from the base station apparatus 100 as described above, Searches for a base station, and provides the search result to the base station apparatus 100.

The method of operation of the base station apparatus 100 according to the present invention is based on the result of searching the target base station in the terminal 10 through steps S250, S255, and S257 described above, It is determined whether or not the search has failed. If it is determined that the terminal 10 fails to search for the target base station, the terminal 10 is changed to the search time 3 longer than the search time 2 set immediately before and the re- If the reselection frequency exceeds the predetermined limit frequency (S275 No), the procedure returns to the above-described step S240. If the reselection frequency exceeds the preset limit frequency (S275 No), the terminal 10 has finally failed in the target base station search and terminates the target base station search and provides the VoLTE service to the terminal 10 through the connected call session through step S220 described above.

The operation method of the base station apparatus 100 according to the present invention is the same as the method of operating the terminal 10 in the above-described S257 No, If the target base station search is determined to have failed, the search frequency of the other base station, for example, the base station 200 according to the search result may be increased by one and stored in the history information (S280).

Therefore, when the base station not included in the neighbor list is searched by the terminal, the operation method of the base station apparatus 100 according to the present invention manages the history information while increasing the search frequency of the base station by one.

The method of operation of the base station apparatus 100 according to the present invention is a method in which if a base station (e.g., the base station apparatus 200) according to a search result of searching for a target base station in the terminal 10 is not included in the neighbor list, (S280). If it is determined that the base station 200 has been searched for more than a predetermined number of times based on the history information (S285 Yes), the number of searches of the base station 200 is increased by one (S290). If it is determined that the base station apparatus 200 has not been searched for a predetermined number of times or more based on the history information (S285 No), the base station apparatus 200 may perform the above-described step S270.

The method of operating the base station apparatus 100 according to the present invention is a method of operating the base station apparatus 200 to transmit data to the neighboring base station apparatus 100 after the terminal 10 uses the specific communication service, You can add it to the list.

After the base station 200 is added to the neighbor list, if the base station 200 is included in the search result of searching for the target base station in the terminal 10, the base station 200 is included in the neighbor list The operation method of the base station apparatus 100 according to the present invention will cause the base station apparatus 200 to perform handover when the terminal 10 searches for the base station apparatus 200 as a target base station.

Therefore, the method of operating the base station apparatus according to the present invention can reduce the unnecessary handover of the terminal while ensuring the quality of the VoLTE service in a situation where various base station apparatuses having different cell coverage are mixed in the same area, By reducing the number of handovers, it is possible to reduce the time spent by the terminal for handover operations (e.g., measuring and comparing signals from neighboring base stations) and by reducing the handover failure rate.

Further, in deriving the above-mentioned effect, the method of operating the base station apparatus according to the present invention can further improve the handover success rate while minimizing communication service disconnection during a search time consumed for searching for a target base station in a different frequency band The effect can be obtained.

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, when a small base station performs handover to a macro base station for a terminal using communication services such as VoIP and VoLTE in a situation where various base stations are mixed in the same area, Since it is possible to reduce unnecessary handover of the terminal while ensuring the quality of the communication service, as it goes beyond the limit of the existing technology, not only the use of the related technology, but also the possibility of selling or operating the applicable device is sufficient This is an invention that is industrially applicable because it can be practically done.

10: Terminal 100, 100 '100 ": (Small)
200: (macro) base station device

Claims (10)

A call connection request confirmation unit for checking whether a call connection request to the terminal is related to a specific communication service;
If the call connection request is related to the specific communication service, searching for a target base station using a frequency band different from that of the currently connected base station during a search time set in association with the terminal Command section; And
And a handover controller for performing a handover to the searched target base station when the mobile station successfully searches for the target base station in the search result of the target base station in the mobile station. The method according to claim 1,
Wherein the search instruction unit comprises:
If the terminal fails to search the target base station, the terminal searches for a target base station that uses a frequency band different from that of the currently connected base station during the changed search time by setting and changing the search time And the base station apparatus. 3. The method of claim 2,
Wherein the search instruction unit comprises:
Wherein the base station apparatus changes the setting so that the search time associated with the terminal becomes longer as the number of times that the terminal fails to search for the target base station increases. The method according to claim 1,
If the other base station according to the search result is not included in the pre-registered neighbor list, it is determined that the terminal has failed to search the target base station,
And a Naver list control unit for adding the other base station to the neighbor list if it is determined that the other base station has been searched for more than a predetermined number of times based on the history information related to the search result. The method according to claim 1,
The call connection request confirmation unit,
Wherein the base station determines that the call connection request is related to the specific communication service if a specific quality of service separator is specified in the call connection request. 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. A call connection request confirmation step of confirming whether a call connection request to the terminal is related to a specific communication service;
If the call connection request is related to the specific communication service, searching for a target base station using a frequency band different from that of the currently connected base station during a search time set in association with the terminal Command step; And
And a handover control step of performing a handover to the searched target base station when the mobile station successfully searches for the target base station in the search result of the target base station in the mobile station. 8. The method of claim 7,
Wherein the search instruction step comprises:
If the terminal fails to search the target base station, the terminal searches for a target base station that uses a frequency band different from that of the currently connected base station during the changed search time by setting and changing the search time Wherein the base station apparatus comprises: 8. The method of claim 7,
Wherein the search instruction step comprises:
Wherein the change is configured to increase the search time associated with the terminal as the number of times that the terminal fails to search for the target base station increases. 8. The method of claim 7,
The call connection request checking step includes:
And if the call connection request is associated with the specific communication service, if the call connection request specifies a specific quality of service identifier.

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