KR20090113581A - Apparatus and method for processing hand-over in the mobile communication system - Google Patents

Abstract

PURPOSE: A handover process method for improving success rate in handover between FA using a compression mode of WCDMA and an apparatus thereof are provided to improve the success rate of the handover and reduce the load of a wireless network system. CONSTITUTION: A message receiving unit(330) receives a measurement reporting message for handover from a mobile communication terminal(100). A message storing unit(320) stores the measurement report message. The measurement report message about the dissimilar second hand over is received by the receiving unit in processing the measurement report message. A handover processing unit(310) provisionally stores the message storage unit in the measurement report message.

Description

Handover processing method and apparatus therefor in mobile communication system {APPARATUS AND METHOD FOR PROCESSING HAND-OVER IN THE MOBILE COMMUNICATION SYSTEM}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a handover processing method of a mobile communication system, and more particularly, to a method and apparatus for increasing success rate during handover between frequency assignments using a compression mode of WCDMA.

The Universal Mobile Telecommunication Service (UMTS) system is based on the European-style mobile system Global System for Mobile Communications (GSM) and General Packet Radio Services (GPRS) .Wideband Code Division Multiple Access (WCDMA) 3rd Generation Partnership Project (3GPP).

The 3GPP system defines a hand-over procedure and a measurement report procedure to support mobility of a CELL_DCH (CELL_Dedicated channel) terminal.

First, a CELL_DCH terminal indicates a terminal in a Radio Resource Control (RRC) state, which is a connected mode in which the terminal state can transmit and receive signaling with a network. The dedicated data / control channel (DPDCH: Dedicated Physical Data Channel (DPDCH), Dedicated Physical Control Channel (DPDCH)) is set.

"Handover" means that when the cell (serving cell) in which the terminal is located is changed due to the mobility of the terminal, the terminal can continuously receive the dedicated data / control channel received in the changed cell (target cell). Represents a series of procedures.

In addition, "measurement report" indicates a series of procedures in which a terminal measures radio conditions for a current cell and a plurality of adjacent cells adjacent to the current cell and reports them to a network to support the handover.

In summary, the terminal informs the network of a measurement result of a radio state of a current cell and neighbor cells through a measurement reporting message, and if necessary, the network informs the terminal based on the measurement report message. Move to target cell, that is, handover.

In this case, if the network node controlling the target cell is different from the network node controlling the previous cell (serving cell), the information exchange for the terminal between the network nodes, the service information exchange of the terminal, and the data / Resource reservation for control transmission may be performed.

The measurement report for the handover may be as follows: intra-frequency handover, inter-frequency handover, and inter-system handover (Inter-RAT (Radio Access Technology) handover)). Can be classified as a measure for one purpose.

The intra-frequency handover is a handover to a neighbor cell of the same frequency band as the current cell of the terminal, the inter-frequency handover is a handover to a neighbor cell of a frequency band different from the current cell, and the inter-system handover is performed with the current cell. Represents a handover to an adjacent cell belonging to another system.

In addition, the measurement report is defined as two types of periodic measurement report (Periodic measurement report), and event triggered measurement report (Event triggered measurement report) according to the event occurrence.

The periodic measurement report informs a network node of a measurement result of a radio state of a current cell and neighboring cells measured by a terminal periodically at regular intervals. On the other hand, the event generation measurement report is to inform the network node of the measurement result when the event occurs after defining a certain event in advance.

Up to 16 events related to handover are defined among the events defined by such event triggering criteria. Among measurement types, measurement types related to handover include intra-frequency measurements, inter-frequency measurements, and inter-RAT (inter-radio access technology) measurements. The intra-frequency type is a type of measurement related to handover of the same frequency between neighboring cells, and the inter-frequency type of measurement is a type of measurement related to handover between different frequencies of the neighboring cells. In addition, the inter-RAT type is a measurement type related to handover between different radio access standards (GSM, CDMA2000, UMTS, etc.). There are a plurality of events in each of the intra-frequency, inter-frequency, and inter-RAT measurement types, and a handover in which the sum of each of the plurality of events is posted. Up to 16 events related to.

According to the format of a 3GPP (MEASUREMENT REPORT) message of the 3rd Generation Partnership Project (3GPP) standard, a measurement report message is transmitted by the mobile terminal when one event is triggered for each measurement type. In other words, when the reporting criterion of the 'MEASUREMENT CONTROL' message is an event triggering method, the mobile terminal transmits the measurement report message to the radio access network as long as the condition specified in the corresponding event type is satisfied.

However, this method can generate various events in complex cell configurations or unstable propagation environments in areas such as urban areas where UMTS systems are commercially available, and can be generated by various event triggering criteria (eg, event 1x, event 2x, event 3x). At the same time, the transmission of multiple measurement report messages may be caused, and no concrete implementation method has been proposed.

2 illustrates a handover triggering method of a mobile terminal according to the prior art.

Referring to FIG. 2, when a handover event EVENT 1B occurs due to a weak signal strength in a cell currently connected to a base station (S100), a handover measurement report ( A message for handover, such as a handover measurement report, is transmitted to a radio network controller (RNC). (S101) For example, a mobile station (UE) in a busy state is a first base station. If a handover event (EVENT 1B) occurs when moving out of the cell boundary of the cell boundary to the service area of the second base station, a radio network controller (RNC) linked to the second base station. Send a handover measurement report. The radio network controller (RNC) updates an active set of a mobile terminal in response to the handover measurement report. (S109) Here, the handover is a soft handover. The active set refers to a set of cells wirelessly linked with the mobile station for the service between the mobile station and the base station.

When the active set update is completed, the mobile terminal ends the handover triggering of the mobile terminal by transmitting an active set update complete message to the wireless network controller.

However, in the handover triggering method of the mobile terminal according to FIG. 2, when a plurality of events (for example, EVENT 1B and EVENT 2A) are continuously generated, a part of the event (EVENT 2A) is not temporarily processed, There was a problem that the call is lost by the loss.

That is, as shown in FIG. 2, when the handover measurement report triggered at 'EVENT 1B' is not completely processed at the wireless network controller (S108), when the handover measurement report triggered at event 2A is transmitted to the wireless network controller ( S105), the radio network controller has a problem that the handover is finally failed to ignore the event 2A.

In order to solve this problem, Korean Patent Laid-Open Publication No. 2006-129872 (hereinafter referred to as Patent Document 1) discloses a wireless network after transmitting a message for handover to a wireless network controller when a handover event of a mobile terminal is performed. When there is no response to the measurement report message for a predetermined time from the controller, a method of retransmitting the measurement report message is proposed.

However, in the method of Patent Document 1, the event is processed in the RRC (Radio Resource Control) layer of the terminal, but is not processed in the physical layer or due to problems of the mobile terminal itself, such as when the event is not processed from the RRC layer. This is the best method if the event is not handled.

The method of Patent Document 1 addresses the problem of the radio access network itself such that the radio network controller (RNC) ignores another handover event (EVENT 2A) that follows as the other handover event (EVENT 1B) is processed. Not suitable for solving. That is, the method of Patent Document 1 increases the unnecessary traffic and load between the mobile terminal and the wireless network controller because the same measurement report message must be retransmitted to the wireless network controller at least once.

Accordingly, an object of the present invention is to provide a method and apparatus for successfully processing a plurality of consecutive events without increasing the traffic and load between the mobile terminal and the radio network controller.

Other objects and advantages of the invention will be described below and will be appreciated by the practice of the invention. Furthermore, the objects and advantages of the present invention can be realized by means and combinations indicated in the appended claims.

An apparatus for processing inter-cell handover of a mobile communication terminal according to an aspect of the present invention includes: message receiving means for receiving a measurement report message for handover from the mobile communication terminal; Message storage means for storing the measurement report message; And a measurement report message for another second hand-over event while the measurement reporting message for one first hand-over event is processed. When received by the receiving means, a hand that temporarily stores the measurement report message for the second handover in the message storing means, and responds to the second handover event after completing the response to the first handover event. Over-processing means.

In another aspect, a handover processing method includes: receiving a measurement report message according to a first handover event from a mobile communication terminal; Receiving a measurement report message according to a second handover event from the mobile communication terminal while processing a message for a first handover; Storing a measurement report message according to the second handover event; Responding to the message for the first handover; And responding to the message for the second handover based on the measurement report message according to the second handover event.

In this case, the first handover event and the second handover event are preferably different types of handover events. In particular, the first handover event is an intra-frequency handover event, and the second handover event. May be an inter-frequency handover event.

In addition, the handover processing apparatus is a radio network controller (RNC) belonging to a radio access network connecting a mobile communication terminal and a core network.

According to the present invention, it is possible to increase the success rate of handover between frequency assignment (FA) while reducing the load of the wireless network system. In particular, as more FAs are added, it is possible to increase the success rate of EVENT 2A in areas where a lot of FA handovers occur.

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

1 is a diagram illustrating the structure of a general mobile communication system (especially, a mobile communication system based on WCDMA). Hereinafter, the structure of a general mobile communication system and the functions of devices constituting the mobile communication system will be described in detail with reference to FIG. 1.

The mobile communication system includes a core network (CN) 13, a radio network controller (RNC) 12, a base station Node B 11a1, 11a2, 11b1, 11b2, and a mobile terminal (User). Element: UE) 10. The mobile terminal 10 is connected to a base station (Node B) (11a1, 11a2, 11b1, 11b2), the base station (Node B) (11a1, 11a2, 11b1, 11b2) is a radio network controller (RNC) 12 ). In addition, the radio network controller 12 is connected to the core network 13.

The mobile terminal 10 connects the base station (Node B) 11a1, 11a2, 11b1, 11b2 and the radio network controller 12 to access data stored in an external data server or to access other mobile terminals. I use it. Hereinafter, the base station (Node B) 11a1, 11a2, 11b1, 11b2 and the radio network controller 12 are collectively referred to as a radio access network system.

The wireless network controller 12 is connected to a plurality of base stations (Node B) 11a1, 11a2, 11b1, 11b2, and the radio of the plurality of base stations (Node B) 11a1, 11a2, 11b1, 11b2. Manage your resources. In addition, the radio network controller 12 is connected to at least one core network 13. The base station (Node B) (11a1, 11a2, 11b1, 11b2) manages the mobile terminal 10 located in a specific cell area (cell A1 to cell B2), and transmits the data transmitted to the wireless network controller 12 Transmit to another mobile terminal using a mobile communication network. In addition, the base station (Node B) (11a1, 11a2, 11b1, 11b2) transfers the data transmitted from the mobile terminal 10 to the radio network controller 12 using a communication network. The mobile terminal 10 may move to another base station under management of the same radio network controller or to another base station under management of another radio network controller.

In particular, the wireless network controller 300 according to the present invention connected to the mobile terminal 100 through a plurality of base stations 200a and 200b as shown in FIG. 4 includes a message receiving means 330 and a handover processing means 310 and The message storage means 320 is used to process handover attempts according to the procedures shown in FIG. 3.

The message receiving means 330 receives the measurement report message for the handover event transmitted from the mobile terminal 100 and transmits it to the handover processing means 310.

The handover processing unit 310 generates a response message corresponding to the measurement report message received from the message receiving unit 330, and transmits the response message to the mobile terminal 100, the first handover event (for example For example, when a second handover event (for example, EVENT 2A) is received while processing the EVENT 1B, the measurement report message for the second handover event is temporarily stored in the message storing means 320. . Thereafter, when the response to the first handover event is completed, the measurement report message for the second handover event is retrieved from the message storing means 320, and a response message is written to the mobile terminal. Send it.

In addition, the handover processing unit 310 sequentially stores at least one handover event (second handover event → third handover event) sequentially received while processing the first handover event, After the processing of the first handover event is completed, it is also possible to respond to other handover events (second handover event to third handover event) sequentially according to the temporarily stored order.

The message storing means 320 is a device for temporarily storing a measurement report message according to the second handover event sent from the mobile terminal 100 according to the instruction of the handover processing means 310.

Hereinafter, a handover processing method according to the present invention using the radio network controller (RNC) of FIG. 4 will be described with reference to FIG. 3.

3 is a message flow diagram illustrating a handover procedure according to an embodiment of the present invention.

When the signal strength of the current cell (cell A1) is weakened and the handover event EVENT 1B is triggered (S300), the UE 100 measures a measurement report message for handover (Measurement). Reporting message) is transmitted to the radio network controller (RNC) 300. (S301) For example, the mobile terminal 100, which is in a busy state, is out of the cell boundary of the first base station 200a. When a handover event (ie, EVENT 1B) occurs when moving to the service area of the second base station 200b, the handover measurement report message is transmitted to the wireless network controller linked to the second base station.

The handover processing unit 310 that receives the measurement report message according to 'EVENT 1B' from the mobile terminal determines whether there is another measurement report message previously stored in the message storage unit 320. That is, the handover processing unit 310 determines whether there is a 'preferred measurement report message' to be processed before the currently received measurement report message. At this time, if the 'preferred measurement report message' does not exist, the measurement report message according to the 'EVENT 1B' (first handover event) is processed (S308).

When processing the measurement report message according to the 'EVENT 1B' (first handover event) as described above, when the frequency measurement 'EVENT 2A' is triggered due to the change of the optimum frequency (S303), the mobile terminal determines the 'EVENT 2A'. The measurement report message is transmitted to the radio network controller 300 (S305).

The handover processing unit 310 of the wireless network controller that has received the measurement report message according to the 'EVENT 2A' (second handover event) from the mobile terminal 100 is currently 'EVENT 1B' (first handover event). Because it is processing the measurement report message according to the " EVENT 2A " (second handover event), it cannot be processed immediately. Therefore, the handover processing means 310 temporarily stores the measurement report message according to the 'EVENT 2A' in the message storage means 320.

Thereafter, the wireless network controller 300 sends an activation set update message to the mobile terminal in response to the 'EVENT 1B' (first handover event) (S109) On the other hand, the mobile terminal updates the active set. In response to the message, the active set update completion message is sent to the radio network controller (S111).

After the response to the 'EVENT 1B' (first handover event) is completed, the handover processing unit 310 of the wireless network controller reports the measurement according to the 'EVENT 2A' previously stored from the message storing unit 320. Invoke the message and process 'EVENT 2A' (S113).

That is, the wireless network controller sends a physical channel reconfiguration message or an RB reconfiguration message to the mobile terminal in response to the measurement report for 'EVENT 2A' (S115).

As described above, the method and apparatus for handover processing according to the present invention temporarily stores a measurement report message for a second handover event when another second handover event is triggered while processing the first handover event. After the processing of the first handover event is completed, the second handover event is processed.

Therefore, there is no need for handover failure or retransmission of the same measurement report message from the mobile terminal due to loss or disregard of the measurement report message.

In the above described with reference to the accompanying drawings, preferred embodiments of the present invention in detail. However, embodiments of the present invention can be variously modified or applied by those skilled in the art, the scope of the technical idea according to the present invention should be determined by the claims to be described later will be.

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 diagram illustrating a configuration of a general mobile communication system.

2 is a diagram illustrating a handover processing procedure of a mobile terminal according to the prior art.

3 is a diagram illustrating a handover processing procedure of a mobile terminal according to the present invention.

4 is a diagram illustrating a detailed configuration of a wireless network controller according to the present invention.

Claims (5)

An apparatus for processing an inter-cell handover of a mobile communication terminal, Message receiving means for receiving a measurement report message for handover from the mobile communication terminal; Message storage means for storing the measurement report message; And During processing of a measurement reporting message for one first handover event, a measurement report message for another second handover event is received. When received by the means, temporarily storing a measurement report message for the second handover in the message storing means, and responding to the second handover event after completing the response to the first handover event. Handover processing apparatus comprising a processing means. The method of claim 1, And the first handover event and the second handover event are different types of handover events. The method of claim 2, Wherein the first handover event is an intra-frequency handover event, and the second handover event is an inter-frequency handover event. The method of claim 3, wherein And the handover processing apparatus is a radio network controller (RNC) for connecting a mobile communication terminal and a core network. Receiving a measurement report message for a first handover event from a mobile communication terminal; Receiving a measurement report message for a second handover event from the mobile terminal while processing the measurement report message for the first handover event; Storing a measurement report message for the second handover event; Responding to a measurement report message for the first handover event; And Responding to the measurement report message for the second handover event.

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