KR102018697B1 - Base station apparatus and control method thereof - Google Patents

Abstract

According to the present invention, in a situation where various base stations are mixed in the same region, a small base station arbitrarily hands over to a macro base station for a terminal using a communication service such as VoIP or VoLTE, thereby ensuring an unnecessary quality of the communication service. Disclosed are a base station apparatus and a method of operating the base station apparatus which can reduce over.

Description

BASE STATION APPARATUS AND CONTROL METHOD THEREOF

The present invention relates to a base station apparatus and a method of operating the base station apparatus. More specifically, in a situation where various base stations are mixed in the same region, a macro base station can be arbitrarily used for a terminal using a communication service such as VoIP and VoLTE. The present invention relates to a base station apparatus and a method of operating the base station apparatus which can reduce unnecessary handover of the terminal while ensuring the quality of communication service by handover.

Recently, heterogeneous network (Heterogeneous Network) technology, in which LTE base stations having different cell sizes are arranged in the same area and increases frequency utilization, is emerging. In a heterogeneous network environment, in addition to the general macro base station, various types of small base stations having smaller coverage are arranged to provide coverage of various types of base stations and to provide wireless communication services to users.

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 a handover is detected, and the serving base station searches for a target base station satisfying a handover condition to the terminal. Provide search control information.

Accordingly, the terminal measures the signal strength of the neighboring base stations based on the search control information, searches whether there is a target base station satisfying the handover condition, and performs a handover to switch to another found base station.

However, in the heterogeneous network environment as described above, as the user moves, the terminal will measure the signal of the neighbor base station of greater intensity than the signal of the serving base station, and the number of handovers of the terminal will increase unnecessarily. .

On the other hand, if the communication service used by the terminal through the base station is a communication service such as VoIP, VoLTE, it is very important to ensure the quality of the communication service to a certain level or more. Therefore, in order to ensure the quality of the communication service, the terminal using the communication service such as VoIP and VoLTE is required to handover the access switch to the base station having the largest signal strength.

However, in the heterogeneous network environment as described above, as the handover of the terminal becomes too frequent, a communication service quality such as VoIP and VoLTE may not be guaranteed.

Therefore, in the present invention, in a situation where various base stations are mixed in the same region, for a terminal using a communication service such as VoIP or VoLTE through the base station, unnecessary handover of the terminal can be reduced while still ensuring the quality of the communication service. I would like to propose a solution.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a small base station with an arbitrary handover to a macro base station for a terminal using a communication service such as VoIP or VoLTE. The present invention provides a base station apparatus and a method of operating the base station apparatus that can reduce unnecessary handover of the terminal while ensuring.

The base station apparatus according to the first aspect of the present invention for achieving the above object comprises: a call connection request confirmation unit for confirming whether a call connection request for a terminal is associated with a specific communication service; A search for instructing the terminal to search for a target base station using a different frequency band from the currently connected base station apparatus when the call connection request is related to the specific communication service as a result of the checking; Command unit; And a handover control unit for handing over the terminal to the searched target base station when the search result of the search for the target base station in the terminal is successful.

Preferably, when the terminal fails to search the target base station as a result of the search, the search command unit changes the search time to set a different frequency band from the base station apparatus to which the terminal is currently connected during the changed set search time. The target base station to be used can be rescanned.

Preferably, the search command unit may change and set 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 another base station according to the search result is not included in the registered neighbor list, it is determined that the terminal has failed to search the target base station, and the other base station is based on the history information related to the search result. If it is determined that the search has been a predetermined number or more may further include a neighbor list control unit for adding the other base station to the neighbor list.

Preferably, the call connection request confirmation unit, if a specific quality of service identifier is specified in the call connection request, it can be confirmed that the call connection request is related to the specific communication service.

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

A method of operating a base station apparatus according to a second aspect of the present invention for achieving the above object comprises: a call connection request confirmation step of confirming whether a call connection request for a terminal is associated with a specific communication service; A search for instructing the terminal to search for a target base station using a different frequency band from the currently connected base station apparatus when the call connection request is related to the specific communication service as a result of the checking; Command step; And a handover control step of handing over the terminal to the searched target base station when the search result of the search for the target base station by the terminal succeeds in searching for the target base station.

Preferably, in the search command step, when the terminal fails to search the target base station as a result of the search, the search time is changed and set to a different frequency band than the base station apparatus to which the terminal is currently connected during the changed search time. It can be to re-search the target base station using.

Preferably, the search command step may be set so that the search time associated with the terminal becomes longer as the number of times that the terminal fails to search the target base station increases.

Preferably, the call connection request confirmation step, if a specific quality of service separator is specified in the call connection request, it can be confirmed that the call connection request is related to the specific communication service.

Therefore, according to the operation method of the base station apparatus and the base station apparatus of the present invention, in the situation where various base station apparatuses having different cell coverage in the same region are mixed, it is possible to reduce unnecessary handover of the terminal while guaranteeing the quality of the VoLTE service. By reducing the number of handovers as described above, an additional effect of reducing the time that the UE spends for handover (eg, measuring and comparing signals of neighboring base stations) and lowering the handover failure rate can be derived.

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

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

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 transmits and receives data between a terminal 10 to use a communication service with a counterpart device (not shown) based on a specific network, and the terminal 10 and the counterpart device (not shown). By doing so, the terminal 10 may include base station apparatuses 100, 100 ′, 100 ″, and 200 supporting the communication service.

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

In addition, a communication service based on a specific network, that is, an 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, a VoIP service using an LTE network, Means a communication service such as VoLTE (hereinafter referred to as VoLTE service).

The base station apparatuses 100, 100 ′, 100 ″, 200 are base stations supporting access 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. And, the base station apparatus 100, 100', 100" which is a small base station may be used. The cell coverage (1,1 ', 1 ") may be included in the cell coverage 2 of the base station apparatus 200 which is a macro base station.

At this time, since the cell coverage 1, 1 ', 1 "of the base station apparatus 100, 100', 100" which is a small base station belongs to the cell coverage 2 of the base station apparatus 200 which is a macro base station, the base station apparatus 200 ) And the base station apparatus 100, 100 ', 100 ", when the same frequency band is used, the terminal 10 in the boundary area of the cell coverage (1, 1', 1") of the base station apparatus 200 and the base station apparatus 100, 100 ' Ping-Pong (Ping-Pong) may occur between the " 100 " and the signal of the base station apparatus 200 and the signal of the base station apparatus 100, 100 ', 100 " Signal quality may be degraded in the boundary region of (1 ', 1 ").

Therefore, 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, a small base station The base station apparatuses 100, 100 ', 100 " use a frequency band of 1.8 GHz, and the base station apparatus 200 that is a macro base station can use a frequency band of 800 MHz.

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

The terminal 10 is a terminal capable of using a communication service by connecting to a specific network (LTE network) through base station apparatuses 100, 100 ′, 100 ″, 200 and transmitting and receiving data with a counterpart apparatus (not shown).

For example, referring to the data service, the terminal 10 accesses a specific network (LTE network) through the base station apparatuses 100, 100 ′, 100 ″, 200, and the other device, that is, a data service (eg, a download service or a streaming service). The data service can be used by transmitting and receiving data with a data service apparatus (not shown) that provides a service, an SNS service, a portal service, and the like.

On the other hand, referring to the VoLTE service, the terminal 10 is connected to a specific network (LTE network) through the base station apparatus (100, 100 ', 100 ", 200), the counterpart device (i.e., not shown) of the VoLTE service By sending and receiving VoLTE data, VoLTE service can be used.

That is, the terminal 10 may access a specific network (LTE network) through the base station apparatus 100, 100 ′, 100 ″, 200, and may use a data service or a VoLTE service based on the specific network (LTE network). have.

Hereinafter, for convenience of description, a state in which the terminal 10 is pre-connected to the base station apparatus 100, that is, the terminal 10 is located in the cell coverage 1 of the base station apparatus 100 to the base station apparatus 100. In the connected state, the base station apparatus according to the present invention is a base station apparatus (100, 100 ', 100 ") which is a small base station, and the base station apparatus 100 will be described with reference to the representative.

When the base station apparatus 100 according to the present invention receives a call connection request for the connected terminal 10, the base station apparatus 100 performs a call connection procedure to connect a call session according to the call connection request with the terminal 10. ) Enables communication services (eg data services or VoLTE services) through call sessions.

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

Here, the specific communication service is a communication service requiring a service quality guarantee of a certain level or more, and may be, for example, the above-described VoLTE service.

In other words, when the base station apparatus 100 receives a call connection request for the terminal 10 from an associated device (eg, MME), the base station apparatus 100 performs a call connection procedure and performs a call session according to the call connection request. On the other hand, it is checked whether the call connection request to the terminal 10 is related to a specific communication service, that is, VoLTE service.

Thus, when the base station apparatus 100 determines that the call connection request for the terminal 10 is related to a specific communication service, that is, a VoLTE service, the base station apparatus 100 is currently connected to the terminal 10 during a search time set in relation to the terminal 10. Instructs the search for the target base station using a different frequency band than the base station apparatus 100.

In more detail, in the process of accessing the base station apparatus 100 by the terminal 10, the base station apparatus 100 designates to which frequency band the terminal 10 should handover when performing the handover. Information will be provided. For example, if the base station apparatus 100 uses 1.8 GHz as described above, the base station apparatus 100 may provide the terminal 10 with designated information for designating a different frequency band, that is, 800 MHz.

Accordingly, the terminal 10 is already provided with the designation information by the base station apparatus 100, and the terminal 10 is based on the above-described designation information during the search time according to the search command from the base station apparatus 100. By measuring the signal strength of the other base station using a different frequency band (for example 800MHz) than the currently connected base station apparatus 100 to search the target base station, and provides the search results to the base station apparatus 100 .

As described above with reference to FIG. 1, in order to avoid a handover ping-pong phenomenon and a deterioration in signal quality in the boundary region of cell coverage 1, 1 ′, 1 ″, the base station apparatus 200 and the base station. Since the apparatuses 100, 100 ', 100 "use different frequency bands, the terminal 10 is a base station apparatus 200 as a target base station which provides a specific communication service using a different frequency band from the base station apparatus 100. Will confirm.

When the base station apparatus 100 determines that the terminal 10 has successfully searched for the target base station based on the search result provided by the terminal 10, the base station apparatus 100 hands over the terminal 10 to the searched target base station, for example, the base station apparatus 200. By doing so, the terminal 10 can be provided with a specific communication service through the base station apparatus 200.

In the conventional base station apparatus, the terminal detects a situation in which a handover is required, and then the terminal requests the handover until the terminal searches for the target base station.

For example, a case in which the 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 will be described. Do it.

In this case, if the base station apparatus 100, 100 ′, 100 ″ was a conventional small base station, the terminal 10 continuously measures a signal for a neighboring base station and enters the cell coverage 1 from the cell coverage 1. While detecting a need for 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, a handover is requested to the base station apparatus 100 to the base station apparatus 100'. Performing a handover to switch the access, and entering the cell coverage 1 "from the cell coverage 1 ', the handover of which the signal strength of the base station apparatus 100" becomes larger than the signal strength of the currently connected base station apparatus 100' When a necessary situation is detected, the terminal 10 requests the handover to the base station apparatus 100 'and performs a handover to switch the access to the base station apparatus 100 ", so that the terminal 10 receives the base station apparatus 100' from the base station apparatus 100. Can be handed over several times to the base station apparatus 100 " will be.

As such, in a situation where various base station apparatuses 100, 100 ′, 100 ″, 200 having different cell coverages in the same region are mixed, the number of handovers according to the movement of the terminal 10 increases, which is the terminal 10. This results in time-consuming operations for performing handovers (eg, measurement and comparison of signals from neighboring base stations) and increases the handover failure rate.

In particular, if the terminal 10 is using the VoLTE service to guarantee a certain level or more of quality, as the handover of the terminal 10 becomes too frequent, the quality of the VoLTE service may not be guaranteed.

However, the base station apparatus 100 according to the present invention arbitrarily targets the terminal 10 to the terminal 10 using a specific communication service, that is, a VoLTE service, regardless of a handover request from the terminal 10. Since the mobile station is handed over to the base station apparatus 200 which is the macro base station by searching for the base station, and the terminal 10 uses the VoLTE service through the base station apparatus 200, as described above, the terminal 10 has the cell coverage (1). In the case of moving from the cell coverage (1 ') to the cell coverage (1 ") will continue to use the VoLTE service through the base station apparatus 200 without handover.

On the other hand, if the base station apparatus 100 that provides a communication service (eg, VoLTE service or data service) to various terminals including the terminal 10 using 1.8 GHz, in order to handover the terminal 10, another frequency is used. If there is a direct search for a target base station using a band, that is, 800 MHz, since the base station apparatus 100 cannot use 1.8 GHz during the search, the communication used by all the terminals including the terminal 10 connected to the base station apparatus 100 is in use. The service (eg VoLTE service or data service) will be disconnected.

Accordingly, the base station apparatus 100 of the present invention does not directly search for a target base station for handing over the terminal 10 using a specific communication service, and causes the terminal 10 to have a frequency band different from that of the base station apparatus 100. Search for a target base station using < RTI ID = 0.0 >

Of course, since the terminal 10 also cannot use 1.8 GHz during a search time for searching for a target base station by measuring the signal strength of another base station using a different frequency band, that is, 800 MHz, from the base station apparatus 100, The specific communication service in use during the search will be disconnected.

As such, the terminal 10 is searching for a target base station in a frequency band other than the frequency band (for example, 1.8 GHz) (for example, 800 MHz) used to minimize a specific communication service disconnection phenomenon of the terminal 10 generated. The scheme will be mentioned in the detailed description with reference to FIG. 2 below.

As described above, the base station apparatus 100 according to the present invention, in a situation where various base station apparatuses 100, 100 ′, 100 ″, 200 having different cell coverage in the same region are mixed, the terminal while guaranteeing the quality of the VoLTE service. Unnecessary handover of 10 can be reduced, and by reducing the number of handovers as described above, the time required for the terminal 10 to perform an operation for handover (eg, measuring and comparing signals of neighboring base stations) and handover failure rate Again, the additional effect of lowering can be derived.

In addition, the base station apparatus 100, which is a small base station with a small capacity, hands over the terminal 10 using the VoLTE service to the base station apparatus 200, which is a macro base station, and consequently the VoLTE to the terminal 10. Since it is possible to secure radio resources to be allocated for the service, it is possible to expect an effect of providing a higher quality data service to another terminal such as a terminal using a data service.

Hereinafter, a 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. 2. For convenience of description, reference will be made to reference numerals of the base station apparatus 100.

The base station apparatus 100 according to the present invention includes a call connection request confirmation unit 110 confirming whether a call connection request for a terminal 10 is related to a specific communication service, and the call connection request is determined by the call connection request. In the case of a specific communication service, a search command unit for instructing the terminal 10 to search for a target base station using a different frequency band from the currently connected base station apparatus 100 during the search time set in relation to the terminal 10 ( 120 and the handover control unit 130 for handing over the terminal 10 to the found target base station when the terminal 10 successfully searches for the target base station. Include.

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

Here, the specific communication service is a communication service requiring a service quality guarantee of a certain level or more, and may be, for example, the above-described VoLTE service.

Accordingly, the call connection request confirmation unit 110 may check whether the call connection request for the terminal 10 is related to the VoLTE service.

In more detail, the call connection request confirmation unit 110 may determine that the call connection request is related to the VoLTE service when 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 that attempts a VoLTE service to a counterpart device (not shown) or may be a called party that receives a VoLTE service attempted from a counterpart device (not shown).

In this way, the terminal 10 accepts the reception of the VoLTE service attempted by the terminal 10 to the counterpart device (not shown), or the terminal 10 receives the reception of the VoLTE service attempted from the counterpart device (not shown). If accepted, the associated equipment (eg, MME) of a specific network (LTE network) that recognizes this, the terminal 10 is a call connection request requesting the terminal 10 to connect the call session for the transmission and reception of VoLTE data of the VoLTE service Is provided to the connected base station apparatus 100, and the base station to which the counterpart apparatus (not shown) connects a call connection request requesting a counterpart apparatus (not shown) to connect a call session for transmitting / receiving VoLTE data of a VoLTE service. Will be provided as an apparatus (not shown).

In addition, when the terminal 10 attempts to use a general data service, a related device (eg, an MME) of a specific network (LTE network) that recognizes this, a call session for data transmission and reception of a data service with respect to the terminal 10. The call connection request requesting the connection to the terminal 10 will be provided to the base station apparatus 100 is connected.

Accordingly, when the base station apparatus 100 receives a call connection request for the terminal 10 from an associated device (eg, MME), the base station apparatus 100 performs a call connection procedure to connect a call session according to the call connection request with the terminal 10. As a result, the terminal 10 may use a communication service (eg, a data service or a VoLTE service).

Here, in the call connection request (eg, E-RAB Setup Request) for the terminal 10 provided from related equipment (eg, MME), a quality of service identifier (QCI) is provided as information on what kind of call session should be connected. : QoS Class Indicator) is specified.

For example, a call connection request requesting a call session connection of a VoLTE service will be assigned QCI # 1 or QCI # 2 for guaranteeing a quality of service suitable for use of a VoLTE service, and a call connection request requesting a call session connection of a data service. QCI # 5 or QCI # 6 shall be designated to ensure the quality of service suitable for data service use.

Accordingly, the call connection request confirmation unit 110, when a call connection request for the terminal 10 is received from the associated equipment (eg, MME) to the base station apparatus 100, a specific quality of service identifier, QCI # in the call connection request. You can check whether the call connection request is related to VoLTE service by checking whether 1 or QCI # 2 is specified.

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

The search command unit 120, when the call connection request to the terminal 10 is confirmed as a result of the call connection request check unit 110 is associated with a specific communication service, the terminal (10) during the search time set in relation to the terminal 10; 10) instructs a search to search for a target base station using a frequency band different from that of the base station apparatus 100 currently connected.

Accordingly, the terminal 10 may use another base station in the vicinity of using a different frequency band (for example, 800 MHz) from the base station apparatus 100 based on the above-described designated information during the search time according to the search command from the base station apparatus 100. By measuring the signal strength with respect to the presence of the target base station, the search results will be provided to the base station apparatus (100).

At this time, the terminal 10 using a specific communication service through the base station apparatus 100 using 1.8 GHz as described above, the search for measuring the signal strength of the other base station using a different frequency band, that is 800 MHz than the base station apparatus 100 Since 1.8GHz is not available during the time period, the specific communication service that was in use during the search time will be disconnected.

Accordingly, the embodiment of the present invention as a method for minimizing a specific communication service disconnection phenomenon of the terminal 10 in the base station apparatus 100 according to the present invention will be described in detail.

First, the search command unit 120, if the call connection request to the terminal 10 is confirmed as a result of the call connection request confirmation unit 110 associated with a specific communication service, during the search time set in relation to the terminal 10 The terminal 10 instructs to search for a target base station using a frequency band different from that of the base station apparatus 100 currently connected.

That is, the search command unit 120, when a call connection request for the terminal 10 is associated with a specific communication service, sets a search time (eg, gapOFFset) associated with the terminal 10, and sets a specific reception wait time ( By operating a timer counting T) and providing a search command including a search time to the terminal 10, the terminal 10 may be instructed to search for the target base station during the search time according to the search command.

In this case, the search command unit 120 preferably sets the initial search time set in relation to the terminal 10 to be the shortest. Hereinafter, the initial search time will be referred to as search time 1.

Accordingly, the terminal 10 searches whether there is a target base station using a frequency band different from the base station apparatus 100 (eg, 800 MHz) during the search time 1 according to the search command from the base station apparatus 100 as described above. The search result will be provided to the base station apparatus 100.

More preferably, the terminal 10 is connected to other base stations in the vicinity using a frequency band different from the base station apparatus 100 (eg, 800 MHz) during the search time 1 according to the search command from the base station apparatus 100 as described above. By measuring the signal strength for the target base station that satisfies the handover condition is searched for, and the search result can be provided to the base station apparatus (100).

For example, the terminal 10, based on the result of measuring the signal strength of the other base station around the other using a different frequency band (for example 800MHz) than the base station apparatus 100, the signal strength is other than the predetermined threshold strength value The base station may be searched as being a target base station satisfying the handover condition.

The search command unit 120 determines whether the terminal 10 has failed to search for the target base station based on a search result of searching for the target base station in the terminal 10.

More specifically, the search command unit 120 does not receive a search result from the terminal 10 so that a specific reception waiting time T elapses, or information included in the search result is invalid, or If the other base station is not included in the neighbor list, the terminal 10 may determine that the target base station search has failed.

That is, the search command unit 120, 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 terminal 10 receives the target base station search. I think it failed.

Further, even if a search result is received from the terminal 10 before the specific reception waiting time T elapses, the search command unit 120 checks whether the information included in the search result is valid, and if it is found to be invalid. The terminal 10 determines that the target base station search has failed. In this case, the search result may include identification information (eg, PCI), signal strength value, etc. of another base station (eg, the base station apparatus 200) searched by the terminal 10. Thus, the search command unit 120 may determine that the information is not valid when the search result does not include identification information (eg, PCI) and signal strength values meeting a normal standard.

Further, even if the information included in the search result is confirmed, the search command unit 120 does not include the other base station according to the search result, that is, the base station apparatus 200 in the neighbor list registered in the base station apparatus 100. In this case, the terminal 10 determines that the target base station search has failed.

At this time, the search command unit 120 is determined based on the history information described later, even if it is determined that the other base station, that is, the base station apparatus 200 has been searched more than a predetermined number of times according to the search result, the terminal 10 to the target base station search It is desirable to judge that it has failed.

On the other hand, the search command unit 120, the search result is received from the terminal 10 before the specific reception waiting time (T) has elapsed, the information included in the search result is valid, and the other base station or base station according to the search result If the device 200 is included in the neighbor list, the terminal 10 may determine that the target base station search is successful.

Accordingly, when the terminal 10 successfully searches for the target base station, the handover control unit 130 hands over the terminal 10 to the found target base station.

That is, when the handover control unit 130 determines that the terminal 10 has successfully searched for the target base station as a result of the determination of the search command unit 120, the handover controller 130 handovers the terminal 10 to the searched target base station, for example, the base station apparatus 200. The terminal 10 may use the specific communication service, that is, VoLTE service, used through the base station apparatus 100 through the base station apparatus 200.

On the other hand, if the search command unit 120 determines that the terminal 10 has failed to search for the target base station, the search command unit 120 changes the search time and sets the base station apparatus currently connected to the terminal 10 during the changed search time. It is possible to rescan the target base station using a frequency band different from 100).

In this case, the search command unit 120 may be configured to change the search time associated with the terminal 10 to increase 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 the search time set in relation to the terminal 10 when the terminal 10 fails to search for the target base station based on the above-described determination result, and at this time, the terminal 10 Since the target base station search has failed, the search time is changed to be longer than the previously set search time 1. In the following, it will be referred to the change set to the search time 2 longer than the search time 1.

As such, when the search command unit 120 changes and sets the search time 2 with respect to the terminal 10, the search command unit 120 operates a timer for counting a specific reception wait time T and issues a search command including the search time. ), The terminal 10 can be instructed to re-search the target base station during the search time 2 according to the search command.

Accordingly, the terminal 10 uses a different frequency band (eg, 800 MHz) from the base station apparatus 100 during the search time 2 according to the search command from the base station apparatus 100 as described above, and satisfies the handover condition. The base station apparatus 100 searches for the presence of the base station and provides the search result to the base station apparatus 100.

Accordingly, the search command unit 120 may determine whether the terminal 10 has failed to search for the target base station based on the search result of searching for the target base station in the terminal 10 as described above.

Thus, if the terminal 10 fails to search for the target base station based on the determination result, the search command unit 120 changes the search time set in relation to the terminal 10 and sets the terminal 10 again. Since the target base station has failed to search at, it will be changed to the search time 3 longer than the previously set search time 2.

Here, the search command unit 120 may be set to change the search time longer by a certain number each time the target base station search fails, or may be set to change the search time longer by a larger value as the number of failures increases. In addition, the search time can be changed to be longer by the value set by the operator regardless of the number of failures.

As described above, since the terminal 10 cannot use 1.8 GHz during the search time for measuring the signal strength of another base station using a different frequency band, that is, 800 MHz, from the base station apparatus 100, the communication service that was in use during the search time ( Example: VoLTE service) will be disconnected.

In this case, a shorter search time can reduce the time for which the communication service is disconnected, but instead, the accuracy of the search results can be reduced and the handover success rate can be lowered. However, a situation may arise in which the time for which the communication service is disconnected becomes long, instead.

In consideration of such a situation, the base station apparatus 100 of the present invention initially searches the target base station of another frequency band for the terminal 10 that is to search for the target base station for inter-band handover. The communication service disconnection time of the terminal 10 can be minimized. Furthermore, whenever the target base station search fails, the terminal 10 re-searches the target base station of another frequency band gradually for a long time, thereby increasing the accuracy of the search result. To increase the handover success rate.

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

The neighbor list controller 140 is based on the history information related to the search result when the other base station (eg, the base station apparatus 200) according to the search result of searching for the target base station in the terminal 10 is not included in the neighbor list. If it is determined that the other base station (eg, the base station apparatus 200) has been searched for a predetermined number of times or more, the other base station (eg, the base station apparatus 200) is added to the neighbor list.

More specifically, in the above-described search command unit 120, the terminal 10 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. If it is determined that the search for the target base station has failed, the number of searches of the base station apparatus 200 may be increased by one time and stored in the history information.

Therefore, when the 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 number of searches of the base station once.

Therefore, the neighbor list control unit 140, if the other base station (eg, the base station apparatus 200) according to the search result of the search for the target base station in the terminal 10 is not included in the neighbor list, the history managed so far When the number of searches of the base station apparatus 200 is increased by one time and the base station apparatus 200 is determined to be searched more than a predetermined number of times based on the history information, the base station apparatus 200 may be added to the neighbor list. .

In this case, the neighbor list controller 140 may add the base station apparatus 200 to the neighbor list after the use of a specific communication service, ie, VoLTE service, that the terminal 10 is using through the base station apparatus 100 is terminated. .

Thus, after the base station apparatus 200 is added to the neighbor list, when the search result of searching for the target base station by the terminal 10 includes the base station apparatus 200, the base station apparatus 200 is included in the neighbor list. As such, the base station apparatus 100 will hand over to the base station apparatus 200 when the terminal 10 searches for the base station apparatus 200 as the target base station.

Accordingly, the base station apparatus 100 according to the present invention can reduce unnecessary handover of the terminal while guaranteeing the quality of the VoLTE service in a situation where various base station apparatuses having different cell coverages in the same region are mixed. By reducing the number of handovers, it is possible to derive the additional effect of reducing the time spent by the UE for handover (eg, measuring and comparing signals of neighbor base stations) and lowering the handover failure rate.

Furthermore, the base station apparatus 100 according to the present invention further increases the handover success rate while minimizing the disconnection of the communication service during the search time spent by the terminal in searching for the target base station in another frequency band. It can derive the effect that makes it possible.

Hereinafter, a method of operating a base station apparatus according to a preferred embodiment of the present invention will be described with reference to FIGS. 3 and 4. Hereinafter, for convenience of description, the base station apparatus 100 will be described with reference.

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. 3.

In a state in which the terminal 10 is connected to the base station apparatus 100 (S10), the base station apparatus 100 receives a call connection request for the terminal 10 from a related device (eg, MME) of a specific network (LTE network). When received (S20), according to the call connection request to the terminal 10, by performing a call connection procedure to connect the call session according to the call connection request with the terminal 10 through a call session in the terminal 10 through a call session (Eg, data service or VoLTE service) can be used (S30).

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

Thus, when the base station apparatus 100 determines that the call connection request for the terminal 10 is related to a specific communication service, that is, VoLTE service, as a result of checking in step S40, a search time (eg: During the search time 1), the terminal 10 instructs to search for a target base station using a different frequency band from the currently connected base station apparatus 100 (S50).

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

The terminal 10 is already provided with the designation information by the base station apparatus 100, and the terminal 10 is based on the above-described designation information during the search time 1 according to the search command from the base station apparatus 100. The base station apparatus 100 searches for the presence of a target base station by measuring signal strength of another base station using a different frequency band (for example, 800 MHz) from the base station apparatus 100 (S60), and provides the search result to the base station apparatus 100. (S65).

As described above, the base station apparatus 100 determines whether the terminal 10 has failed to search for the target base station based on a search result provided from the terminal 10, that is, a search result of searching for the target base station in the terminal 10. To judge.

For example, when the base station apparatus 100 determines that the terminal 10 has failed to search for the target base station (S70), the base station apparatus 100 changes the search time 1 set in relation to the terminal 10, and the terminal 10 is changed. The target base station is searched again during the search time (eg, search time 2) (S90).

In this case, the base station apparatus 100 may change and set the search time associated with the terminal 10 to increase as the number of times that the terminal 10 fails to search for the target base station increases. That is, the search time 2 will be longer than the search time 1 described above.

As a result, the terminal 10 may use a different frequency band (eg, 800 MHz) different from the base station apparatus 100 based on the above-described designated information during the search time 2 according to the search command from the base station apparatus 100. The signal strength of the base station is measured to search for the presence of the target base station (S100), and the search result is provided to the base station apparatus 100 (S105).

As described above, the base station apparatus 100 determines whether the terminal 10 has failed to search for the target base station based on a search result provided from the terminal 10, that is, a search result of searching for the target base station in the terminal 10. To judge.

For example, if the base station apparatus 100 determines that the terminal 10 has successfully searched for the target base station (S110), the terminal 10 hands over the searched target base station, for example, the base station apparatus 200 (S120).

That is, if it is determined that the terminal 10 has successfully searched for the target base station, the base station apparatus 100 hands over the terminal 10 to the searched target base station, for example, the base station apparatus 200 (S120). The specific communication service that is being used through the base station apparatus 100, that is, the VoLTE service, may be used 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 step S30 described above, thereby providing a communication service (eg, a data service or a VoLTE service) through the call session in the terminal 10. After making it available, since the time for handing over the terminal 10 to the target base station, for example, the base station apparatus 200 through the above steps S40 to S120 is very short, the terminal 10 is viewed from the user's point of view of the terminal 10. It will not be recognized 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 can arbitrarily identify a terminal 10 using a specific communication service, that is, a VoLTE service, irrespective of a handover request from the terminal 10. 10) by handing over to the base station apparatus 200, which is a macro base station, by searching for the target base station, unnecessary handover of the terminal 10 can be reduced while ensuring the quality of the VoLTE service.

Hereinafter, a method of operating a base station apparatus according to a preferred embodiment of the present invention will be described with reference to FIG. 4. For convenience of description, reference will be made to the reference number of the base station apparatus 100.

In the operation method of the base station apparatus 100 according to the present invention, when a call connection request for the terminal 10 is received (S200) in a state in which the terminal 10 is already connected (S210), the call connection request is received. Accordingly, by performing a call connection procedure to connect the call session according to the call connection request with the terminal 10, it will provide a communication service (eg, data service or VoLTE service) to the terminal 10 (S220).

On the other hand, the operation method of the base station apparatus 100 according to the present invention, when a call connection request for the terminal 10 is received (S210), whether or not the call connection request for the terminal 10 is associated with a specific communication service Check (S230).

Here, the specific communication service is a communication service requiring a service quality guarantee of a certain level or more, and may be, for example, the above-described VoLTE service.

In more detail, the operation method of the base station apparatus 100 according to the present invention, when receiving a call connection request for the terminal 10 from the associated equipment (for example, MME), specific service quality identifiers to the call connection request That is, by checking whether QCI # 1 or QCI # 2 is specified, it is possible to confirm whether a call connection request is related to VoLTE service.

That is, in the operating method of the base station apparatus 100 according to the present invention, if QCI # 1 or QCI # 2 is specified in the call connection request for the terminal 10, the call connection request will be confirmed to be related to the VoLTE service. .

Accordingly, in the method of operating the base station apparatus 100 according to the present invention, if the call connection request to the terminal 10 is designated QCI # 1 or QCI # 2, the call connection request is confirmed to be associated with the VoLTE service ( S230 Yes), during the search time set in relation to the terminal 10, the terminal 10 instructs to search for a target base station using a different frequency band from the currently connected base station apparatus 100 (S240).

That is, in the method of operating the base station apparatus 100 according to the present invention, when a call connection request for the terminal 10 is related to a specific communication service, a search time (for example, gapOFFset) related to the terminal 10 is set. By operating a timer for counting a specific reception waiting time T and providing a search command including a search time to the terminal 10, the base station apparatus 100 currently connected during the search time according to the search command is received by the terminal 10. Command to search for a target base station using a different frequency band than?

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

Accordingly, the terminal 10 uses a different frequency band (eg, 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 satisfies the handover condition. The base station apparatus 100 searches for the presence of the base station and provides the search result to the base station apparatus 100.

In the operation method of the base station apparatus 100 according to the present invention, the terminal 10 determines whether the terminal 10 has failed to search for the target base station based on a search result of searching for the target base station.

More specifically, in the method of operating the base station apparatus 100 according to the present invention, if a search result is not received from the terminal 10 so that a specific reception waiting time T elapses based on the timer operated as described above (S250). No), it is determined that the terminal 10 has failed to search for the target base station.

In addition, in the method of operating the base station apparatus 100 according to the present invention, even if a search result is received from the terminal 10 before a specific reception waiting time T elapses (S250 Yes), the information included in the search result is valid. If it is confirmed that it is not valid (S255 No), the terminal 10 determines that the target base station search has failed.

In addition, in the operation method of the base station apparatus 100 according to the present invention, even if the information included in the search result is confirmed to be valid (S255 Yes), the other base station, that is, the base station apparatus 200 according to the search result is the base station apparatus 100 If it is not included in the neighbor list already registered (S257 No), it is determined that the terminal 10 has failed to search for the target base station.

On the other hand, in the operation method of the base station apparatus 100 according to the present invention, the search result is received from the terminal 10 before the specific reception waiting time T elapses, and the information included in the search result is valid, If the specific other base station apparatus according to the base station apparatus 200 is included in the neighbor list (S257 Yes), it can be determined that the terminal 10 is successful in the target base station search.

In the method of operating the base station apparatus 100 according to the present invention, if the terminal 10 successfully searches for a target base station (for example, the base station apparatus 200), the terminal 10 is referred to as a target base station, that is, the base station apparatus 200. ) To allow the terminal 10 to use a specific communication service that is being used through the base station apparatus 100, that is, the VoLTE service, through the base station apparatus 200 (S260).

On the other hand, the operation method of the base station apparatus 100 according to the present invention, if it is determined that the terminal 10 has failed to search for the target base station, as described above S250 No, S255 No, S257 No, set in relation to the terminal 10 The search time is changed and set so that the terminal 10 re-searches the target base station using a different frequency band from the currently connected base station apparatus 100 during the changed search time.

In this case, in the method of operating the base station apparatus 100 according to the present invention, it is preferable that the terminal 10 changes the search time associated with the terminal 10 as the number of times that the target base station fails to search increases.

That is, in the method of operating the base station apparatus 100 according to the present invention, if the terminal 10 fails to search for the target base station, the search time set in relation to the terminal 10 is changed and set, and the terminal 10 Since the target base station failed to search, the search time is changed to be longer than the previously set search time 1. In the following, it will be referred to the change set to the search time 2 longer than the search time 1.

More specifically, in the operation method of the base station apparatus 100 according to the present invention, if it is determined that the terminal 10 fails to search for another base station apparatus in the above-described S250 No, S255 No, S257 No, the terminal 10 The search time 1 set in relation to the change is set to a longer search time 2 and the number of rescans is increased by 1 (S270).

Accordingly, in the method of operating the base station apparatus 100 according to the present invention, if the number of rescans does not exceed a preset limit (S275 Yes), the timer returns to step S240 and counts a specific reception waiting time T. By operating and instructing the terminal 10 to re-search the target base station, the terminal 10 causes the terminal 10 to search for the target base station during the search time 2.

Accordingly, the terminal 10 uses a different frequency band (eg, 800 MHz) from the base station apparatus 100 during the search time 2 according to the search command from the base station apparatus 100 as described above, and satisfies the handover condition. The base station apparatus 100 searches for the presence of the base station and provides the search result to the base station apparatus 100.

Accordingly, in the method of operating the base station apparatus 100 according to the present invention, the terminal 10 determines the target base station based on a search result of the terminal 10 searching for the target base station through steps S250, S255, and S257 described above. If it is determined that the search has failed, and the determination result is that the terminal 10 fails to search the target base station, the terminal 10 changes to a search time 3 longer than the search time 2 previously set with respect to the terminal 10, and sets the number of re-searches. If it increases (S270), if the number of rescans does not exceed the preset limit (S275 Yes), the procedure of returning to step S240 will be repeated, and if the number of rescans exceeds the preset limit (S275 No), the terminal ( 10) determines that the target base station search has finally failed, and ends the target base station search, and provides the VoLTE service to the terminal 10 through the call session connected through step S220.

In this case, the case in which the terminal 10 determines that the target base station search has failed in more detail in the above-described S257 No. In more detail, the operation method of the base station apparatus 100 according to the present invention includes the terminal 10 in the above-described S257 No. If it is determined that the search for the target base station has failed, the search frequency of another base station, for example, the base station apparatus 200, may be increased by one time according to the search result and stored in the history information (S280).

Therefore, in the operation method of the base station apparatus 100 according to the present invention, when the base station not included in the neighbor list is searched by the terminal, the history information is managed while increasing the number of times of searching for the corresponding base station once.

Accordingly, in the method of operating the base station apparatus 100 according to the present invention, when another base station (eg, 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, In the history information that has been managed so far, the number of times of searching for the base station apparatus 200 is increased by one time and stored (S280). If the base station apparatus 200 is added to the neighbor list (S290), and 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 (S285No), step S270 may be performed.

At this time, the operation method of the base station apparatus 100 according to the present invention, after the use of a specific communication service, that is, VoLTE service that the terminal 10 is using through the base station apparatus 100 is terminated, the base station apparatus 200 Can be added to the list.

Thus, after the base station apparatus 200 is added to the neighbor list, when the search result of searching for the target base station by the terminal 10 includes the base station apparatus 200, the base station apparatus 200 is included in the neighbor list. Therefore, in the method of operating the base station apparatus 100 according to the present invention, when the terminal 10 searches for the base station apparatus 200 as the target base station, it will hand over to the base station apparatus 200.

Accordingly, the method of operating the base station apparatus according to the present invention can reduce unnecessary handover of the terminal while guaranteeing the quality of the VoLTE service in a situation where various base station apparatuses having different cell coverages are mixed in the same region. By reducing the number of handovers, it is possible to derive the additional effect of reducing the time spent by the UE for handover (eg, measuring and comparing signals of neighbor base stations) and lowering the handover failure rate.

Furthermore, in the operation method of the base station apparatus according to the present invention, in order to derive the above effects, the handover success rate is further increased while minimizing the disconnection of the communication service during the search time spent by the terminal in searching for the target base station in another frequency band. It can derive the effect that makes it possible.

A method of operating a base station apparatus according to an embodiment of the present invention may be implemented in the form of program instructions that can be executed by various computer means and recorded in a computer readable medium. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. Program instructions recorded on the media may be those specially designed and constructed for the purposes of the present invention, or they may be of the kind well-known and available to those having skill in the computer software arts. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tape, optical media such as CD-ROMs, DVDs, and magnetic disks, 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 not only machine code generated by a compiler, but also high-level language code that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to the above-described embodiments, and the technical field to which the present invention belongs without departing from the gist of the present invention as claimed in the following claims. Anyone skilled in the art will have the technical idea of the present invention to the extent that various modifications or changes are possible.

According to an operation method of a base station apparatus and a base station apparatus according to the present invention, in a situation where various base stations are mixed in the same region, a small base station arbitrarily hands over a terminal using a communication service such as VoIP and VoLTE to a macro base station. Since it can reduce unnecessary handover of the terminal while guaranteeing the quality of the communication service, the possibility of commercialization or sales of the applied device as well as the use of the related technology as well as the use of the related technology is not only sufficient, but also realistically. It is an invention with industrial applicability, since it can be clarified.

10: terminal 100,100'.100 ": (small) base station apparatus
200: (macro) base station apparatus

Claims (10)

A call connection request confirmation unit confirming whether the call connection request is related to a specific communication service when a call connection request for the terminal is received;
A search command unit for instructing the terminal to search for a target base station using a frequency band different from that of the currently connected base station apparatus when the call connection request is related to the specific communication service; And
And a handover control unit for handing over the terminal to the found target base station when the terminal succeeds in searching for the target base station according to the command. The method of claim 1,
The search command unit,
When the terminal fails to search the target base station as a result of the search, the search time is changed and set so that the terminal re-searches a target base station using a different frequency band than the currently connected base station apparatus during the changed search time. Base station apparatus, characterized in that. The method of claim 2,
The search command unit,
And changing 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 of claim 1,
If the other base station according to the search result is not included in the registered neighbor list, it is determined that the terminal failed to search the target base station,
And a neighbor list controller configured to add the other base station to the neighbor list if it is determined that the other base station has been searched for a predetermined number of times or more based on the history information related to the search result. The method of claim 1,
The call connection request confirmation unit,
And a specific quality of service identifier is specified in the call connection request, and confirms that the call connection request is related to the specific communication service. The method of claim 1,
The specific communication service,
A base station apparatus, characterized in that the communication service requiring a certain level of quality of service guarantee. A call connection request confirmation step of confirming whether the call connection request is related to a specific communication service when a call connection request for the terminal is received;
A search command step of instructing the terminal to search for a target base station using a frequency band different from that of the currently connected base station apparatus when the call connection request is related to the specific communication service; And
And a handover control step of handing over the terminal to the searched target base station if the terminal succeeds in searching for the target base station according to the command. The method of claim 7, wherein
The search command step,
When the terminal fails to search the target base station as a result of the search, the search time is changed and set so that the terminal re-searches a target base station using a different frequency band than the currently connected base station apparatus during the changed search time. Method of operation of the base station apparatus, characterized in that. The method of claim 7, wherein
The search command step,
And changing and setting the search time associated with the terminal to increase as the number of times that the terminal fails to search for the target base station increases. The method of claim 7, wherein
The call connection request confirmation step,
And if a specific quality of service identifier is specified in the call connection request, confirming that the call connection request is related to the specific communication service.

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