KR20090046035A - Method and system for load balancing in wireless communication system - Google Patents

Abstract

The present invention provides a method for load balancing in a wireless communication system, when a handover event for load balancing occurs, selecting a terminal to be a handover target, and for at least one selected terminal Transmitting a base station handover request (BSHO-REQ) message including an allowable sub cell or base station IDs; and for the allowable sub cell or the BSIDs. The total radio network utilization rate is applied to the BS_init HO initiated by the base station, including the process of performing a handover by transmitting a handover indication (HO-IND) for notifying the handover status and the target BSID. Can be maximized.

Load Balancing, Handover, Sub-Cell Base Station ID (BSID).

Description

METHOD AND SYSTEM FOR LOAD BALANCING IN WIRELESS COMMUNICATION SYSTEM}

The present invention relates to load balancing in a communication system, and more particularly, to a method and apparatus for performing load balancing using a handover (BS_Init HO) initiated by a base station in a cellular system.

In a conventional circuit switched based communication network such as Code Division Multiple Access (CDMA) or Global System for Mobile (GSM), since the required capacity and allocated radio resources are constant for each connection, Load Balancing is performed. You only need to check the number of subscribers and connections. In the following description, one connection is called a service flow (hereinafter referred to as "SF").

However, in third generation wireless communication systems such as broadband wireless communication systems (e.g. IEEE 802.16e standard) or 3rd Generation Partnership Project 2 (3GPP2), various traffic characteristics (real-time vs. non-real-time, constant bit rate (CBR) vs. Multimedia applications with variable bit rate (VBR), etc. must be simultaneously supported by a single base station, and advanced access technologies (e.g., AMC, HARQ, PF scheduling, and MIMO) are applied differently according to the traffic characteristics. Checking only the number and the number of connections made load balancing difficult. Due to these various traffic characteristics, call admission control also needs to check the bandwidth requirements of each connection by traffic type, and the RF scheduler also has a burden of scheduling the differential processing time for each connection.

In relation to current load balancing, the current broadband wireless communication system (for example, IEEE 802.16e standard) has the following problems.

A specific operation scenario for the base station handover request BSHO-REQ initiated by the base station is not defined in the specification. That is, the BSHO-REQ is not triggered by what event, and the UE that receives the BSHO-REQ message is not specifically defined. For example, when the full load of the currently serving subcell is high, when the HO operation mode field value of the BSHO-REQ is set to "1" (Mandatory HO request), the UE according to the current specification is HO_IND (Handover). Indication) message to respond. In this case, the terminal considers the radio channel state of the serving sub-cell as a scanning start condition, and thus, there is a high possibility that the terminal does not perform any operation or rejects the handover during handover due to load balancing.

In the initial network entry procedure, if the UE succeeds until the registration procedure is completed in the system and the pre-provisioned static QoS setup procedure fails, the initial access procedure fails. There is no countermeasure other than using the BSHO-REQ message as a direct counterbalance countermeasure.

In the cellular system, a method and system for performing load balancing using a handover (BS_Init HO) originating from a base station are proposed and solved.

According to a first aspect of the present invention for achieving the above object, in a method for load balancing in a wireless communication system, when a handover event for load balancing occurs, the terminal to be handed over Selecting, transmitting a base station handover request (BSHO-REQ) message including subcells or base station IDs (BSIDs) allowable for the selected at least one terminal; And performing a handover by transmitting a handover indication (HO-IND) for notifying the allowable subcell or the BSIDs of the handover and a target BSID.

According to a second aspect of the present invention for achieving the above object, in the method for load balancing in a wireless communication system, when a handover event for load balancing occurs, selecting a terminal to be a handover target and Transmitting a base station handover request (BSHO-REQ) message including subcells or base station IDs (BSIDs) allowable for the selected at least one terminal; And transmitting a scanning response (SCN-RSP) message for notifying a scanning interval for at least one terminal.

According to a third aspect of the present invention for achieving the above object, in the method for load balancing in a wireless communication system, when a handover event for load balancing occurs, selecting a terminal to be handover target and Transmitting a scanning response (SCN-RSP) message for notifying a scanning interval for the at least one selected terminal; and transmitting a scanning report (SCN-RSP) message for notifying the scanning result. Characterized in that it comprises a process.

According to a fourth aspect of the present invention for achieving the above object, in a system for load balancing in a wireless communication system, when a handover event for load balancing occurs, the terminal to be handed over A base station for selecting and transmitting a base station handover request (BSHO-REQ) message including subcells or base station IDs (BSIDs) allowable for the at least one selected terminal; And a terminal executing a handover by transmitting a handover indication (HO-IND) for notifying the handover of the allowable subcell or the BSIDs and a target BSID.

According to a fifth aspect of the present invention for achieving the above object, in a system for load balancing in a wireless communication system, when a handover event for load balancing occurs, select a terminal to be handover target, Transmitting a base station handover request (BSHO-REQ) message including subcells or base station IDs (BSIDs) allowable for the selected at least one terminal, and selecting the at least one terminal And a base station transmitting a scanning response (SCN-RSP) message for notifying the scanning interval for the scan.

According to a sixth aspect of the present invention for achieving the above object, in a system for load balancing in a wireless communication system, when a handover event for load balancing occurs, the terminal to be handover target is selected, and A base station transmitting a scanning response (SCN-RSP) message for notifying a scanning interval for at least one or more selected terminals, and a terminal transmitting a scanning report (SCN-RSP) message for notifying the scanning result. Characterized in that it comprises a.

In a cellular network, when a base station manages one or more sub-cells in one sector, sub-cell: 1FA / 1sector, a limited air resource is balanced to multiple users. By suggesting a method and apparatus that can be distributed, it is possible to maximize the radio resource utilization. In addition, it is applied to the BS_init HO initiated by the base station for the purpose of recommending BSIDs (Base Station IDs) having a good radio channel state while satisfying the quality of service (QoS) requirements of the terminal. Wireless network utilization can be maximized.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, detailed descriptions of related well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

Hereinafter, the present invention applies to a handover (BS_init HO) initiated by the base station when the base station manages one or more subcells (sub-cell: 1FA / 1sector) in one sector in a cellular system. A method and a system for performing load balancing will be described.

In the following description of the drawings 1 to 8, in the present invention, a broadband wireless communication system (for example, an IEEE 802.16 system) will be described as an example.

Here, if some basic assumptions are made in the present invention, first, the base station can know the number of users per sub-cell, the number of flows per QoS type, and the CPU load. Second, base station IDentifier (BSID) is transmitted for each subcell through NBR-ADV (Neighbor Advertisement). When two FAs are allocated to one sector, two subcells are listed and two BSIDs are listed. That is, BSIDs for all neighbor sub-cells to be handed over are transmitted. Third, BSIDs for all neighboring subcells to be handed over may be listed in a base station handover request (BSHO-REQ). Fourth, the serving base station knows whether the BSIDs in the NBR-ADV belong to the same sector. Fifth, the UE does not scan its own BSID included in the NBR-ADV message when handoverable subcells have low carrier-to-interference-plus-noise-ratio (CINR) / RSSI (received signal strength indication). You can search them. Sixth, the base station should set the HO operation mode field value to "1" in the BSHO-REQ or BSHO-RSP to notify that the terminal should perform the handover. At this time, the UE should inform whether the handover is performed through the HO-IND. If the UE is capable of handover, the UE executes the handover with the value of the HO_IND_type field as "0b00", and sets it as "0b10" when rejecting the handover. . Finally, the base station stops bearer traffic until immediately after the scanning interval timer expires or until the SCN-REP (Scanning Report) is received. . If SCN-REP is received first, bearer traffic transmission is resumed at that time.

1 is a flowchart illustrating an operation of a base station for load balancing according to a first embodiment of the present invention.

Referring to FIG. 1, the base station broadcasts an NBR_ADV message in step 100. The NBR_ADV message generally provides channel information for neighboring base stations provided by Downlink Channel Descriptor (DCD) / Uplink Channel Descriptor (UCD) message transmission of each base station. To this end, the base station may receive a DCD / UCD message of the adjacent base station via the backbone.

Thereafter, the base station determines whether a handover trigger occurs in step 102, and if the handover trigger does not occur, the base station proceeds to step 100 and transmits an NBR_ADV message. If a handover trigger occurs, the base station proceeds to step 104 to select a terminal to be a handover target.

Here, the handover trigger may consider triggering due to radio resource variation, triggering by a call processing request, triggering by a ranging procedure, and triggering according to a change of a radio channel state of a terminal. That is, in the present invention, the handover trigger event occurs in consideration of load equality.

Triggering by the radio resource variation occurs when the used radio capacity of the serving subcell exceeds an acceptable load threshold (including a backhaul capacity or radio capacity variation). Triggering by the call processing request occurs when the load threshold is exceeded due to the required bandwidth (WW) when requesting a new call processing (set, change, or terminate). In the triggering by the ranging procedure, when the initial network entry, re-entry, or handover is performed, the terminal moves to a target subcell to perform a ranging request (RNG-REQ), and changes to another FA beyond an allowable load threshold. Occurs when notifying with ranging response (RNG-RSP). In this case, the base station must instruct the terminal to scan through the RNG-RSP, and after the RNG-RSP to send a scanning response to specify the scanning interval (starting interval) and the start frame (start frame) or the terminal through the scanning request Scanning interval and start frame must be specified. Finally, the terminal should send a SCN-REP to the base station. Finally, the triggering according to the change of the radio channel state of the terminal is based on the downlink radio channel state by a channel quality indicator channel (CQICH) or SCN-REP or the change of the uplink radio channel state for uplink traffic of the terminal. For example, the base station may collect radio channel state information of various subcells (or BSIDs) of the terminal to recommend subcells (or BSIDs) having the best radio channel states. At this time, whether to accept the terminal is considered a load state, of course, load equality is not the main purpose.

In addition, when the handover triggers, the UE selection method for BSHO-REQ in the corresponding subcell may consider various things as follows. First, select a terminal requesting a handover trigger (in addition, considering a condition in which a CINR / RSSI of a wireless channel state satisfies a certain condition), randomly selecting a terminal, or randomly selecting a terminal having only non-real-time traffic; For example, a terminal having a low subscriber level may be selected, or a terminal having the smallest number of active or admitted flows may be selected. Depending on the implementation, selecting a terminal with a large number of uplink flows among UEs having a bad CINR value (sending a UE having a poor CINR to another subcell BSID has no gain because there is no interference change in the downlink. In case of uplink, a gain may be large) or a terminal in a sleep mode may be selected. Also, depending on the implementation, the terminal selection may be randomly selected by combining the conditions of the various terminal selection schemes described above.

Thereafter, the base station proceeds to step 106 and other subcells (or BSIDs) that can be allowed within the same sector for the selected UEs and / or other subcells that can be allowed (without considering the same sector). Are sent via the BSHO-REQ message. That is, the base station transmits a BSID list for all neighbor sub-cells to be subjected to handover through a BSHO-REQ message.

Here, when notifying the allowable subcells through the BSHO-REQ, the base station may select and transmit only subcells that do not generate ping pong in consideration of a radio channel state (radio resource efficiency or delay ( in terms of latency). For reference, when the load of the serving subcell is full, the HO operation mode field value of the BSHO-REQ is set to "1" (mandatory HO), and the load balancing is not the main purpose, but the QoS requirements of the UE. When considering the wireless channel state while satisfying these requirements, the HO operation mode field value of the BSHO-REQ may be set to “0” (recommend HO).

Thereafter, the base station checks whether there is a scanning request from the terminal in step 108, and receives a scanning request (SCN_REQ) message from the terminal in step 110 when the scanning request is received.

BSHO-REQ is generated not because of bad wireless channel condition but because of load balancing. The UE receives BSHO-REQ without receiving a scanning response (SCN-RSP) message from the base station. It should be possible to start scanning for allowable BSIDs included in the BSHO-REQ regardless of downlink (DL) radio channel status. If the UE starts scanning only when the radio channel state of the serving subcell satisfies a specific condition, the specific condition information is set to a trigger TLV in the specification in a Downlink Channel Descriptor (DCD) or NBR_ADV (Neighbor BSs Advertisement). It can be notified or delivered in addition to the BSHO-REQ parameter.

In another embodiment, the same parameters as those included in the SCN-RSP may be added to the BSHO-REQ as needed. For example, the scanning interval corresponds to this. In addition, the parameter having different characteristics according to the terminal, such as the scanning interval, may notify the base station by the terminal at the time of initial network entry (eg, REG-REQ). For example, the trigger condition for starting the SCN-REQ) can be informed to the terminal (eg, REG-RSP). In addition, the base station may request (SCN-RSP) and report (SCN-REP) the radio channel status of the serving subcell as well as the neighbor sub-cell (Temp_BSID = 0 for the serving subcell). Notice). Although the base station is already reporting the radio channel status through the CQICH, scanning the serving subcells together to improve the performance in order to compare the scanning results under the same scanning period with the target subcells. Can be.

Thereafter, the base station stops transmitting bearer traffic while transmitting an SCN-RSP message for the scanning request in step 112. In step 114, the base station receives a scanning result from the terminal through an SCN_REP message and resumes bearer traffic transmission. In this case, the SCN-REP message transmission may or may not be transmitted as a terminal selection.

If there is no scanning request in step 108, the base station proceeds to step 116 and step 118. In other words, when the base station sets the HO operation mode field value to "1" and transmits a BSHO-REQ message to the selected terminal, the terminal immediately responds with a HO-IND message and then performs a handover procedure. At this time, if the BS transmits all allowable BSIDs in order according to the load state (in order of lowest load), the UE attempts handover to the first BSID or performs scanning on the UE itself to perform the most wireless channel. A handover may be selected by selecting a good BSID.

In step 116, the base station receives a HO_IND message from the terminal to inform handover cancellation or rejection.

Thereafter, when the base station rejects the handover in step 118, the base station proceeds to step 102 and performs a handover (BS_init HO) procedure starting from the base station for load balancing. In this case, the same terminal may be performed or another terminal may be selected and performed.

Thereafter, the base station terminates the procedure for load balancing.

2 is a flowchart illustrating an operation of a terminal for load balancing according to the first embodiment of the present invention.

Referring to FIG. 2, in step 200, the UE receives a BSHO-REQ message including subcells (or BSIDs) allowable from the corresponding base station.

Thereafter, when scanning is required for the allowable subcells in step 202, the terminal proceeds to step 204 and transmits a scanning request message to the base station.

Thereafter, the terminal receives a scanning response message for the scanning request in step 206 and transmits a scanning result for the allowable subcells (or BSIDs) to the base station through a scanning report (SCN-REP) message in step 208. do. In some implementations, the SCN-REP message transmission may not be transmitted as a terminal option.

Thereafter, in step 210, the terminal designates a target BSID to be handed over together with handover and transmits the target BSID to the base station through a HO-IND message.

Thereafter, the terminal performs a handover for load balancing in step 212.

Thereafter, the terminal terminates the procedure for load balancing.

3 is a flowchart illustrating an operation of a base station for load balancing according to a second embodiment of the present invention.

Referring to FIG. 3, the base station broadcasts an NBR_ADV message in step 300.

Thereafter, the base station checks the handover trigger in step 302, and when the handover trigger is not necessary, the base station proceeds to step 300 and transmits an NBR_ADV message. If a handover trigger is required, the base station proceeds to step 304 to select a terminal to be a handover target. Here, the handover trigger may consider triggering due to radio resource variation, triggering by a call processing request, triggering by a ranging procedure, and triggering according to a change of a radio channel state of a terminal. That is, in the present invention, the handover trigger event is generated to consider load equality. For details, refer to step 104 of FIG. 1. When the handover trigger is performed, a method of selecting a terminal to be a BSHO-REQ target in the corresponding subcell is referred to step 104 of FIG. 1.

Thereafter, the base station proceeds to step 306 and transmits other subcells (or BSIDs) that can be allowed for the selected terminals through a BSHO-REQ message. In this case, when the base station informs the allowable subcells through the BSHO-REQ, only the subcells that do not generate a ping pong in consideration of a radio channel state may transmit (radio resource efficiency or latency). In terms of performance).

In step 308, the base station transmits a scanning response message requesting a scanning result together with the scanning interval information to the selected terminal.

Depending on the implementation, other sub-cells (BSIDs) and scanning information (eg, scanning intervals) that can be allowed for the selected UE while the handover is triggered are transmitted to the UE through the BSHO-REQ message and the scanning result is transmitted. You may be instructed to notify.

Thereafter, the base station receives a scanning result from the terminal through the SCN_REP message in step 310 and resumes bearer traffic transmission. In this case, the SCN-REP message transmission may or may not be transmitted as a terminal selection. In addition, the base station receives a HO_IND message indicating whether the handover from the terminal. When notifying the handover rejection through the HO-IND, the base station may perform a handover (BS_init HO) starting from the base station for load balancing from the beginning again.

According to an implementation, when the BSHO-REQ is triggered, other sub-cells (BSIDs) and scanning information that are allowed for the selected UE are transmitted to the UE through a BSHO-REQ message and instructed to notify the scanning result. In step 310, the base station receives an SCN_REP message instead of a HO_IND message indicating whether the handover is performed. The SCN_REP message means that handover will be performed if the transmission includes the radio channel state value, and that handover will not be performed if a null value is applied. That is, the terminal does not need to separately transmit the role of the SCN_REP message as the HO-IND message. From this point, the base station stops transmitting traffic and the terminal moves to the target subcell (BSID) to perform handover.

Thereafter, the base station terminates the procedure for load balancing.

4 is a flowchart illustrating a terminal operation for load balancing according to a second embodiment of the present invention.

Referring to FIG. 4, in step 400, the UE receives a BSHO-REQ message including subcells (or BSIDs) allowable from the corresponding base station.

In step 402, the terminal receives a scanning response message including the scanning interval information from the base station.

In step 404, the terminal transmits the scanning result to the base station through a scanning report (SCN-REP) message. Or a HO-IND message for notifying whether the handover is transmitted to the base station.

Thereafter, the terminal terminates the procedure for load balancing.

5 is a flowchart illustrating an operation of a base station for load balancing according to a third embodiment of the present invention.

Referring to FIG. 5, the base station broadcasts an NBR_ADV message in step 500.

Thereafter, the base station checks the handover trigger in step 502 and, if the handover trigger is not needed, proceeds to step 500 and transmits an NBR_ADV message. If a handover trigger is required, the base station proceeds to step 504 to select a terminal to be a handover target.

Here, the handover trigger may consider triggering due to radio resource variation, triggering by a call processing request, triggering by a ranging procedure, and triggering according to a change of a radio channel state of a terminal. That is, in the present invention, the handover trigger event is generated to consider load equality. For details, refer to step 104 of FIG. 1. In addition, when the handover trigger is performed, a method of selecting a terminal to be a BSHO-REQ target in the corresponding subcell is referred to step 104 of FIG. 1.

Thereafter, the base station transmits a scanning response (SCN-RSP) message to scan other allowable subcells (BSIDs) for the selected UE in step 506.

In step 508, the base station receives the SCN-REP message and receives a scanning result.

Thereafter, the base station transmits the scanned subcell BSID through a BSHO-REQ message when the radio channel state of the scanned subcell BSID is good in step 510. If another UE having a bad CINR value is selected, the SCN-RSP message transmission can be resumed.

In step 512, the base station receives a HO_IND message indicating whether the handover is performed.

Thereafter, the base station terminates the procedure for load balancing.

6 is a flowchart illustrating an operation of a terminal for load balancing according to a third embodiment of the present invention.

Referring to FIG. 6, the UE selected in the handover trigger state receives an SCN-RSP message including sub-cells (BSIDs) allowable from the base station in step 600.

In step 602, the terminal transmits an SCN-REP message including a scanning result to the corresponding base station.

Then, in step 604, when the radio channel state is good, the terminal receives a BSHO-REQ message including subcells (or BSIDs) allowable from the base station. If the CINR value is bad, another UE may be selected to proceed from the SCN-RSP message transmission again.

In step 606, the terminal transmits a HO-IND message to the base station informing whether the handover has occurred.

Thereafter, the terminal terminates the procedure for load balancing.

Here, the schemes described with reference to FIGS. 1 to 6 are not load balancing, but are also recommended for BS_init HO, which is recommended to recommend BSIDs having good wireless channel conditions while satisfying QoS requirements of the UE. Can be applied.

7 illustrates a base station apparatus for performing load balancing according to an embodiment of the present invention.

Referring to FIG. 7, the terminal 700 includes a load balancer 710, a terminal selector 720, a handover controller 730, and a scanning controller 740.

The load equalization control unit 710 checks whether a handover trigger for load equalization occurs and notifies the terminal selection unit 720. Here, the handover trigger may consider triggering due to radio resource variation, triggering by a call processing request, triggering by a ranging procedure, and triggering according to a change of a radio channel state of a terminal. That is, in the present invention, the handover trigger event occurs in consideration of load equality.

The terminal selector 720 selects a terminal to be handed over when a handover event for load balancing occurs. In addition, when the handover triggers, the UE selection method for BSHO-REQ in the corresponding subcell may consider various things as follows. First, select a terminal requesting a handover trigger (in addition, considering a condition in which a CINR / RSSI of a wireless channel state satisfies a certain condition), randomly selecting a terminal, or randomly selecting a terminal having only non-real-time traffic; For example, a terminal having a low subscriber level may be selected, or a terminal having the smallest number of active or admitted flows may be selected. Depending on the implementation, selecting a terminal with a large number of uplink flows among UEs having a bad CINR value (sending a UE having a poor CINR to another subcell BSID has no gain because there is no interference change in the downlink. In case of uplink, a gain may be large) or a terminal in a sleep mode may be selected. Also, depending on the implementation, the terminal selection may be randomly selected by combining the conditions of the various terminal selection schemes described above.

The handover control unit 730 transmits a base station handover request (BSHO-REQ) message including subcells or base station IDs (BSIDs) allowable for the selected at least one terminal. do. In addition, the handover control unit 730 receives the handover instruction message and then, upon handover rejection, selects the same terminal or another terminal and performs the handover for load balancing again. Notify me.

The scanning controller 740 transmits a scanning response (SCN-RSP) message for notifying a scanning interval for the at least one selected terminal. After receiving the scanning request message, the scanning response message (SCN-RSP) is transmitted.

In some implementations, the scanning control unit 740 receives the scanning report message, selects a terminal having a poor CINR value from the scanning result, and transmits a scanning response message to the handover control unit. When the wireless channel state is good, 730 transmits the corresponding BSID through a base station handover request (BSHO-REQ) message.

8 illustrates a terminal device for performing load balancing according to an embodiment of the present invention.

Referring to FIG. 8, the terminal 800 includes a handover controller 810, a scanning controller 820, and a first determiner 830.

The first determination unit 830 analyzes control messages from the handover control unit 810 and the scanning control unit 820, and notifies a result to the handover control unit 810 and the scanning control unit 820. .

The handover control unit 810 transmits a handover indication (HO-IND) for notifying whether the handover is possible for the allowable subcell or the BSIDs and a target BSID to perform a handover.

The scanning control unit 820 transmits a Scanning Report (SCN-RSP) message informing of a scanning result. Alternatively, after receiving the handover request message, a scanning request (SCN-REQ) message is transmitted.

According to an implementation, after receiving the scanning response message, the handover may be performed by transmitting a handover indication (HO-IND) for notifying the handover status and the target BSID.

After receiving the scanning response message, the handover control unit 810 transmits a handover indication (HO-IND) for notifying the handover status and the target BSID to execute the handover. After receiving the scanning response message, the scanning control unit 820 transmits a scanning report (SCN-REP) message to determine whether to perform a handover according to the presence or absence of a radio channel state value.

Although the above description focuses on load equality, it is also applicable to the case where the BS initiates the handover (BS_init HO) for other reasons. For example, when a particular terminal is placed in a specific sub cell to generate statistics due to a necessity of an operator, and when a group is sent to an area where group communication is possible, roaming is performed. In case of moving, the present invention can also be applied to a case of moving a terminal to a subcell having a lower cost.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

1 is a flowchart illustrating an operation of a base station for load balancing according to a first embodiment of the present invention;

2 is a flowchart illustrating a terminal operation for load balancing according to the first embodiment of the present invention;

3 is a flowchart illustrating an operation of a base station for load balancing according to a second embodiment of the present invention;

4 is a flowchart illustrating an operation of a terminal for load balancing according to the second embodiment of the present invention;

5 is a flowchart illustrating operation of a base station for load balancing according to a third embodiment of the present invention;

6 is a flowchart illustrating a terminal operation for load balancing according to a third embodiment of the present invention;

7 is a diagram of a base station apparatus for performing load balancing according to an embodiment of the present invention;

8 is a terminal device for performing load balancing according to an embodiment of the present invention.

Claims (24)

In the method for load balancing in a wireless communication system, Selecting a terminal to be handed over when a handover event for load balancing occurs; Transmitting a base station handover request (BSHO-REQ) message including subcells or base station IDs (BSIDs) allowable for the selected at least one terminal; And performing handover by transmitting a handover indication (HO-IND) for notifying the allowable subcell or the BSIDs of the handover and a target BSID. Way. The method of claim 1, And receiving the handover instruction message and performing handover for load equalization by selecting the same terminal or another terminal upon handover rejection. The method of claim 1, Transmitting the scanning request (SCN-REQ) message after receiving the handover request message; And after receiving the scanning request message, transmitting the scanning response (SCN-RSP) message. The method of claim 3, wherein And receiving a Scanning Report (SCN-RSP) message after receiving the scanning response message. The method of claim 1, The handover request message may indicate whether allowable subcells or BSIDs are included in the same sector. In the method for load balancing in a wireless communication system, Selecting a terminal to be handed over when a handover event for load balancing occurs; Transmitting a base station handover request (BSHO-REQ) message including subcells or base station IDs (BSIDs) allowable for the selected at least one terminal; And transmitting a scanning response (SCN-RSP) message informing of a scanning interval for the selected at least one terminal. The method of claim 6, And transmitting the scanning result through a scanning report (SCN-RSP) message. The method of claim 6, And performing a handover by transmitting a handover indication (HO-IND) for notifying the handover status and a target BSID after receiving the scanning response message. The method of claim 6, And after receiving the scanning response message, transmitting a scanning report (SCN-REP) message to determine whether or not to perform handover according to the presence or absence of a wireless channel state value. Load balancing method. In the method for load balancing in a wireless communication system, Selecting a terminal to be handed over when a handover event for load balancing occurs; Transmitting a scanning response (SCN-RSP) message informing of a scanning interval for the at least one selected terminal; And transmitting a scanning report (SCN-RSP) message informing the scanning result. The method of claim 10, After receiving the scanning report message, if the wireless channel state is not good from the scanning result, select a terminal with a bad CINR value and transmit a scanning response message, and if the wireless channel state is good, handover request for the corresponding BSID (Base Station The load balancing method further comprising the step of transmitting via a Handover Request: BSHO-REQ message. The method of claim 11, And receiving a handover request message and executing a handover by transmitting a handover indication (HO-IND) message for notifying whether the handover has occurred. In the system for Load Balancing in a wireless communication system, When a handover event for load balancing occurs, a handover request is selected and includes a sub cell or base station IDs (BSIDs) allowable for the at least one or more selected terminals. A base station that transmits a (Base Station Handover Request: BSHO-REQ) message, And a terminal performing handover by transmitting a handover indication (HO-IND) for notifying the allowable subcell or the BSIDs of the handover and a target BSID. system. The method of claim 13, The base station, after receiving the handover instruction message, in the handover reject (Handover reject) characterized in that to perform the handover for load equalization again by selecting the same terminal or another terminal. The method of claim 13, After receiving the handover request message, the terminal transmits a Scanning Request (SCN-REQ) message. And the base station transmits the scanning response (SCN-RSP) message after receiving the scanning request message. The method of claim 15, The terminal receives the scanning response message, and then load scanning system (SCN-RSP) message, characterized in that the load balancing system. The method of claim 13, The handover request message may indicate whether allowable subcells or BSIDs are included in the same sector. In a system for load balancing in a wireless communication system, When a handover event for load balancing occurs, a handover request is selected and includes a sub cell or base station IDs (BSIDs) that are allowable for the at least one selected terminal. And a base station transmitting a base station handover request (BSHO-REQ) message and transmitting a scanning response (SCN-RSP) message for notifying a scanning interval for the selected at least one terminal. Load balancing system. The method of claim 18, And a terminal for transmitting the scanning result through a scanning report (SCN-RSP) message. The method of claim 18, After receiving the scanning response message, the load balancing system further comprises a terminal for performing a handover by transmitting a handover indication (HO-IND) for notifying the handover status and the target BSID . The method of claim 18, After receiving the scanning response message, characterized in that it further comprises a terminal for transmitting through a Scanning Report (SCN-REP) message that can determine whether or not to perform a handover according to the presence or absence of the radio channel state value Load balancing system. In a system for load balancing in a wireless communication system, When a handover event for load balancing occurs, the base station for selecting a terminal to be handover target, and transmits a Scanning Response (SCN-RSP) message for notifying the scanning interval for the at least one selected terminal and the terminal; , And a terminal for transmitting a scanning report (SCN-RSP) message for notifying the scanning result. The method of claim 22, After receiving the scanning report message, the base station selects a terminal having a poor CINR value from the scanning result and transmits a scanning response message to the terminal, and transmits a corresponding BSID when the wireless channel state is good. A load balancing system, characterized in that the transmission to the terminal via a base station handover request (BSHO-REQ) message. The method of claim 23, wherein The terminal performs the handover by transmitting a Handover Indication (HO-IND) message indicating whether the handover after receiving the handover request message.

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