KR101046115B1 - Method for processing handover between FAs in asynchronous mobile communication system and processing device therefor - Google Patents

Abstract

The present invention includes transmitting a handover request message for a first FA from a first RNC to a second RNC; Comparing first FA information included in the handover request message with second FA information of the second RNC; As a result of the comparison, when the first FA information and the second FA information are identical to each other and the second FA is a dummy FA, transmitting a handover failure message to the first RNC; Recognizing that the first FA is a dummy FA boundary section through the handover failure message; And changing the FA information from the first RNC to a third FA included in the second RNC and transmitting a handover request message to the second RNC.

Handover between FA, Compression Mode, SRNC, DRNC, Dummy FA, RNSAP

Description

A method for processing handover between FAs in an asynchronous mobile communication system and a processing apparatus therefor {Method and apparatus for Inter FA handover management in asynchronous mobile communication network}

The present invention relates to handover processing between frequency assignments, and more particularly, to a method and apparatus for performing handover processing between FAs using a dummy FA in an asynchronous mobile communication system.

In the mobile communication system, the mobile station guarantees mobility by providing a handover function so that the call is continuously maintained even if the mobile station leaves the service area of the current base station and enters the service area of the neighboring base station.

In a mobile communication system, a base station is assigned at least one or more frequencies to provide a subscriber service to a mobile station. According to the carrier's policy, a different number of frequencies may be allocated between neighboring base stations. If the used frequency is different between the new base station and the old base station to which the mobile station will move, soft handover cannot be applied. It is common for a hard handover between FAs to be performed.

In a wideband code division multiple access (WCDMA) system, which is a typical asynchronous mobile communication system, to perform handover between FAs, to search for a new frequency signal of a target base station before completely blocking current call setup when a handover situation occurs. Compressed Mode (CM) is used, which supports the function of pausing transmission and reception for a short time of several milliseconds (msec). Inter-FA handover processing using the compression mode method is defined in the 3rd Generation Partnership Project (3GPP) standard. Compression mode can be used to obtain synchronization from the target base station through a new pilot channel and a common pilot channel, so that call disconnection does not occur even if the current call setup is disconnected and the hard handover is performed at the new frequency.

However, in the compressed mode, many factors such as whether the terminal supports the compressed mode, performance, system performance, and wireless environment have a problem in that the success rate of handover is reduced.

An inter-FA handover processing technique proposed as an alternative to the compression mode method is a handover processing method using a dummy FA as shown in FIG. 1. Related patent documents include Korean Patent Registration No. 309886 (Handoff method in a base station using Dummy FA and a mobile communication base station therefor).

Referring to FIG. 1, when the base station A area 10 using two FAs and the base station B area 20 using one FA are adjacent to each other, from the base station B area 20 to the base station A area 10. ), Handover processing can be performed smoothly between cells 22 and 12 serving FA2. On the contrary, when the mobile station moves from the base station A area 10 to the base station B area 20, the cell 22 serving FA 2 has no problem, but the mobile station of the cell 11 serving FA 1 has a handover. Difficult problems arise. That is, when the mobile station using FA 1 moves to the base station B area 20, the mobile station searches for the FA corresponding to the FA 1 in the base station B area 20. If there is no corresponding dummy FA, the base station B area 20 Since there is no FA corresponding to FA 1, the handover fails. To solve this problem, the base station B 20 is provided with a dummy FA cell 21 for generating a dummy frequency without a traffic channel. When the dummy FA exists, the mobile station acquires system information of the base station B to which the dummy FA belongs through the pilot signal of the dummy FA. The mobile station analyzes the system information and performs an inter-FA handover from FA 1 of the base station A area 10 to FA 2 of the base station B area 20 when there is no traffic channel in the FA.

FIG. 2 illustrates a handover processing procedure between Radio Network Controllers (RNCs) performed in a conventional WCDMA network.

Typically, network elements of a WCDMA network include a UMTS Terrestrial radio access network (UTRAN) that manages and controls radio resources, and a core network (CN) that provides switching and routing requests and data access to an external network. Network). Here, the radio access network (UTRAN) includes at least one Radio Network Sub-system (RNS), wherein the RNS includes a plurality of Node Bs, which are connection points for supporting radio section communication of the mobile station, and a plurality of nodes. RNC for managing radio resources for managing and controlling B.

Referring to FIG. 2, when handover is to be performed, RNSAP (RNS) from a SRNC (Serving RNC) 1 to which a Node B currently serving a mobile station is connected, is connected to a DRNC (Drift RNC) 2 adjacent thereto. Application Part) Request message (S10). Accordingly, a radio link setup request message is transmitted from the SRNC 1 to the DRNC 2. Here, the SRNC 1 provides a connection point with the core network CN and handles handover decision, outer loop power control, and the like.

The DRNC 2 determines whether radio resource allocation for handover of the mobile station is possible, and transmits an RNSAP failure message if the mobile station cannot be accommodated (step S20). Accordingly, a radio link setup failure message is transmitted from the DRNC 2 to the SRNC 1.

Subsequently, the SRNC 1 performs a handover between FAs after performing a search for the RNC by applying a CM scheme to search for a new cell capable of handover (steps S30 and S40).

As described above, since the standard for providing dummy FA cell information through RNSAP is not defined, there is a limitation that the CM method can only be applied to handover between FAs.

The present invention has been made to solve the above problems, and provides a method for processing inter-FA handover in an asynchronous mobile communication system that implements inter-RNC handover service using dummy FA cell information, and a processing apparatus therefor. Its purpose is to.

In order to achieve the above object, the present invention includes the steps of (a) transmitting a handover request message for the first FA from the first RNC to the second RNC; (b) comparing first FA information included in the handover request message with second FA information of the second RNC; (c) transmitting a handover failure message to the first RNC when the first FA information and the second FA information are the same as each other and the second FA is a dummy FA; (d) recognizing that the first FA is a dummy FA boundary through the handover failure message; And (e) changing the FA information from the first RNC to a third FA included in the second RNC to transmit a handover request message to the second RNC.

The first RNC may be embodied as a SRNC (Serving RNC), and the second RNC is a DRNC (Drift RNC).

In step (a), it is preferable to perform a procedure for transmitting a general cell radio link setup request message for the first FA from the SRNC to the DRNC according to a handover request of the mobile station.

In step (c), it is preferable to transmit a radio link setup failure message in which a failure cause parameter value is set to indicate that the setup request for the dummy FA is a failure cause as the handover failure message. desirable. In the step (d), it is preferable that the SRNC recognizes the failure cause parameter value to recognize the dummy FA boundary.

In step (e), a procedure of transmitting a radio link setup request message for the third FA from the SRNC to a DRNC and a procedure of transmitting a radio link setup response message from the DRNC to the SRNC Can be done.

According to another aspect of the present invention, in a handover processing apparatus of a radio network controller (RNC) for inter-FA handover processing in an asynchronous mobile communication system, a dummy FA cell from an SRNC (Serving RNC) to which the mobile station is currently connected. An RNSAP message processing unit for receiving a generic cell handover request message for the RNSAP message; A setup failure message processing unit for generating a handover failure message indicating that the setup request for the dummy FA is a failure cause and transmitting the generated failure message to the SRNC; And a handover control unit configured to receive a handover request from the SRNC to a FA other than the dummy FA and perform a radio link setup process. 2. The apparatus for handover processing of a radio network controller (RNC) is provided. do.

Preferably, the RNSAP message processing unit receives a radio link setup request message as the handover request message.

The setup failure message processing unit generates a radio link setup failure message in which a failure cause parameter value indicating that a setup request for a dummy FA is a failure cause is generated as the handover failure message. It is preferable to transmit to SRNC.

According to the present invention, since a standard for providing handover service between RNCs without using a CM scheme is provided in the FA boundary section of the WCDMA network, the handover success rate can be increased, thereby contributing to the improvement of mobility quality of the UE.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

3 is a block diagram illustrating a method for processing inter-FA handover in a WCDMA network performed according to the present invention, and FIG. 4 is a procedure diagram showing an inter-FA handover process according to a preferred embodiment of the present invention. The inter-FA handover processing method according to the present invention is performed in the boundary section of any 1RNC and 2RNC adjacent to each other in a WCDMA network, which is a typical asynchronous mobile communication system. Hereinafter, the configuration of the present invention will be described with reference to a case where the first RNC is an SRNC and the second RNC is a DRNC for convenience of understanding.

FIG. 3 shows a configuration in which an SRNC using two frequencies of FA 1 and FA 2 and a DRNC using dummy FA and FA 2 that have the same FA 1 and FA information but do not provide a traffic channel are adjacent to each other. have. Although it is shown in the drawing that the service for two FAs in the SRNC is not limited to this example, a single FA or three or more FAs may be serviced.

When FA 2 is used when the mobile station moves from the SRNC to the DRNC, the handover process may be smoothly performed from cell 1 to cell 3. However, when the mobile station uses FA 1, since there is no normal cell serving FA 1 in the DRNC, an inter-FA handover processing procedure as shown in FIG. 4 must be performed.

In the inter-FA handover processing procedure provided according to the present invention, when a handover request for an arbitrary first FA is made from the SRNC to the DRNC, the DRNC compares the information of the first FA with the information of any second FA provided by the DRNC. If the first FA information and the second FA information are identical to each other and the second FA corresponds to a dummy FA, handover between FAs is performed to the third FA provided by the DRNC. Here, the first FA is defined as FA 1, the second FA is a dummy FA corresponding to FA 1, and the third FA is defined as FA 2. In addition, it is assumed that FA 1 is a higher FA having a higher frequency than FA 2.

When the mobile station 101 uses FA 1 in cell 0 (Cell 0), the mobile station 101 searches for the FA of cell 2 (Cell 2) corresponding to FA 1 and then sends the measurement report (MR) to the SRNC 103. Send a measurement report) to request a handover (step S100).

Since the SRNC 103 does not have a way to check whether the handover requested cell 2 (Cell 2) is a normal cell or a dummy FA cell because the cell 2 is in a different RNC region, the SRNC 103 assumes that it is a normal cell. The handover request message is transmitted (step S110). Here, the handover request message preferably has a format of a general cell radio link setup request message for cell 2.

The DRNC 104 determines that it is impossible to set up a radio link because the FA cell included in the radio link setup request message corresponds to a dummy FA cell. Accordingly, the DRNC 104 transmits a handover failure message to the SRNC 103 (step S120). Here, the handover failure message preferably has a format of a radio link setup failure message. In this case, a predetermined field of the radio link setup failure message includes a failure cause parameter indicating that a failure has been processed because a radio link setup request has been entered for the dummy FA. The failure cause parameter value may be set to a specific value in various formats previously promised between the RNCs 103 and 104.

When the SRNC 103 receives a radio link setup failure message from which the failure cause parameter value is set from the DRNC 104, the SRNC 103 recognizes that the dummy FA boundary, that is, the FA boundary where the dummy FA cell exists, changes the FA information to be handed over. Attempt to transition to the lower FA. Accordingly, the SRNC 103 transmits a radio link setup request message for the lower FA cell, Cell 3 (Cell 3), to the DRNC 104, and the DRNC 104 responds to the SRNC 103 with a radio link setup response message. (Steps S130 and S140).

After the radio link setup response, the DRNC 104 establishes a radio link and a radio bearer with the Node B 105 corresponding to Cell 3 (steps S145 and S146).

The SRNC 103 then transmits a Physical Channel Reconfiguration message to the mobile station 101 and receives a completion message thereof (steps S150 and S160).

In addition, the SRNC 103 transmits a Radio Link Deletion Request message for FA 1 to the Node B 102 to which the mobile station 101 is connected (step S170 and S180).

Through the above process, the mobile station 101 performs a handover between FAs from the upper FA to the lower FA.

5 shows a main configuration of the handover processing apparatus 100 provided in any RNC for performing the above-described inter-FA handover processing.

Referring to FIG. 5, the handover processing apparatus 100 according to the preferred embodiment of the present invention includes an RNSAP message processing unit 110, a setup failure message processing unit 120, a dummy FA related parameter setting unit 130, and a hand. The over control unit 140 is included.

The RNSAP message processing unit 110 receives a handover request message via the RNSAP protocol from any RNC (SRNC) to which the mobile station is currently connected. RNSAP is a signaling protocol defined between SRNC and DRNC and defines a procedure for supporting mobility of a terminal and a procedure related to establishing and releasing a radio link. Here, the Iur interface should be provided between the SRNC and the DRNC.

The RNSAP message processing unit 110 receives the normal cell radio link setup request message for the FA searched by the mobile station and checks whether the cell of the setup requested FA is a dummy FA cell or a normal cell.

When the setup failure message processing unit 120 receives the normal cell setup request for the dummy FA cell from the SRNC, the radio link setup failure is notified to indicate that the setup request for the dummy cell for the dummy FA cell is a failure cause. Generates a Radio Link Setup Failure message and sends it to the SRNC. In generating the radio link setup failure message, the setup failure message processing unit 120 is provided with processing for setting the failure cause parameter value from the dummy FA related parameter setting unit 130. Here, the failure cause parameter value may be set to a specific value in various formats previously promised between RNCs.

The handover control unit 140 receives a handover request from the SRNC to another FA cell other than the dummy FA cell to perform a radio link setup process. In this regard, the handover control unit 140 transmits a radio link setup response message to the SRNC, and performs a radio link and radio bearer setup with the node B to which the mobile station will connect. .

Through the above configuration, the handover processing apparatus transmits a radio link setup failure message indicating that the setup request for the dummy FA is the cause of failure when the normal cell setup request is received for the dummy FA cell from the SRNC. Accordingly, the SRNC recognizes that the cell to be handed over by the mobile station is not a normal cell but a dummy FA cell, and can perform inter-FA handover by requesting radio link setup for a cell serving another FA.

Although the present invention has been described above by means of limited embodiments and drawings, the present invention is not limited thereto and will be described below by the person skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of the claims.

The following drawings, which are attached to this specification, illustrate preferred embodiments of the present invention, and together with the detailed description of the present invention serve to further understand the technical spirit of the present invention, the present invention includes matters described in such drawings. It should not be construed as limited to.

1 is a configuration diagram for explaining a handover process using a dummy FA performed according to the prior art.

2 is a flowchart schematically illustrating a handover process between an SRNC and a DRNC performed according to the prior art.

3 is a block diagram illustrating a method for inter-FA handover processing in a WCDMA network performed according to the present invention.

4 is a flowchart illustrating an inter-FA handover process in a WCDMA network performed according to a preferred embodiment of the present invention.

5 is a block diagram showing the main configuration of the handover processing apparatus according to a preferred embodiment of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS OF THE DRAWINGS

100: handover processing unit 110: RNSAP message processing unit

120: setup failure message processing unit 130: dummy FA related parameter setting unit

140: handover control unit

Claims (8)

(a) transmitting a handover request message for the first FA from the first RNC to the second RNC; (b) comparing first FA information included in the handover request message with second FA information of the second RNC; (c) transmitting a handover failure message to the first RNC when the first FA information and the second FA information are the same as each other and the second FA is a dummy FA; (d) recognizing that the first FA is a dummy FA boundary through the handover failure message; And (e) changing the FA information in the first RNC to a third FA included in the second RNC and transmitting a handover request message to the second RNC; The first RNC is a serving RNC (SRNC), the second RNC is a DRNC (Drift RNC), In step (a), a procedure for transmitting a general cell radio link setup request message for the first FA from the SRNC to the DRNC is performed according to a handover request of a mobile station, In step (c), as the handover failure message, a radio link setup failure message having a failure cause parameter value set to notify that a setup request for a dummy FA is a failure cause is transmitted. , In step (d), the SRNC recognizes the failure cause parameter value and recognizes the dummy FA boundary section. delete delete delete The method of claim 1, wherein in step (e), Transmitting a radio link setup request message for the third FA from the SRNC to a DRNC; And a method for transmitting a radio link setup response message from the DRNC to the SRNC. A handover processing apparatus of a radio network controller (RNC) for inter-FA handover processing in an asynchronous mobile communication system, A RNSAP message processing unit for receiving a generic cell handover request message for a dummy FA cell from a SRNC (Serving RNC) to which the mobile station is currently connected; A setup failure message processing unit for generating a handover failure message indicating that the setup request for the dummy FA is a failure cause and transmitting the generated failure message to the SRNC; And A handover control unit configured to receive a handover request from the SRNC to a FA other than the dummy FA and perform a radio link setup process; The RNSAP message processing unit receives a Radio Link Setup Request message as the handover request message, The setup failure message processing unit, A radio link setup failure message having a failure cause parameter value indicating that a setup request for a dummy FA is a failure cause as the handover failure message is generated and transmitted to the SRNC. Handover processing apparatus of a radio network controller (RNC). delete delete

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