KR20030032075A - Method for determining a kind of services on handover in mobile communication system - Google Patents

Abstract

PURPOSE: A method for deciding a service type upon handover in a mobile communication system is provided to discriminate the service type for a UE(User Equipment) when the UE is handed over from an SRNC(Serving Radio Network Controller) to a DRNC(Drift Radio Network Controller). CONSTITUTION: A DRNC receives a radio link setup request message from an SRNC(511), and calculates the number of coordinated DCH(Dedicated CHannel) groups(513). The DRNC sets a service type value(svc) of the SRNC to 0(zero)(515), and designates the number of the coordinated DCH groups to a variable, 'j' to set the 'j' to 0(zero)(517). The DRNC calculates the number of DCHs of the coordinated DCH groups, 'j', wherein the number of DCHs is set to 'N'(519). The DRNC sets an idx to 0(zero)(521), and sets a variable, 'k' to 0(zero)(523). The DRNC checks whether a radio bearer having the number of DCHs identical to the number of the coordinated CH groups, 'N' exists, using radio bearer information stored in a database(525). If so, the DRNC stores the radio bearer in a wireless bearer candidate table(527), and if not, the DRNC performs a loop for the variable, 'k'(529). The DRNC checks whether a value of the idx is 0(zero)(531). If so, the DRNC determines error generation and ends the steps(533), and if not 0(zero), the DRNC checks whether the value of the idx is 1(one)(535). If so, the DRNC selects a service indicated by the j-th coordinated DCH group as a radio bearer stored in the candidate table(537), and if not 1(one), the DRNC calculates error values for all radio bearers in the candidate table(539). The DRNC decides a service type of the radio bearers as a radio bearer having a minimum error value(541), and performs a loop for the variable, 'j'(543). If radio bearers are selected for all coordinated DCH groups, the DRNC determines the service type as the combination of the radio bearers(545).

Description

Method of Determining Service Type in Handover in Mobile Communication System {METHOD FOR DETERMINING A KIND OF SERVICES ON HANDOVER IN MOBILE COMMUNICATION SYSTEM}

The present invention relates to a mobile communication system, and more particularly, to a method of determining a service type when handing over to a different wireless network controller.

1 is a diagram schematically illustrating a conventional code division multiple access communication system.

As shown in FIG. 1, all processes related to connection of one user terminal (hereinafter referred to as "UE") are a Radio Network Controller (hereinafter referred to as "RNC"). Will be called). The RNC is responsible for resource allocation for UEs accessing one or more base stations (Node B: hereinafter referred to as "Node B"). A communication system consisting of the Node Bs and RNCs is called a UMTS Terrestrial Radio Access Network (UTRAN).

As described above, when the RNC allocates resources to the UE and successfully connects, the UE continues communication using a dedicated physical channel (hereinafter referred to as DPCH) in a downlink or an uplink. Let's go. The W-CDMA system uses an asynchronous scheme in which UEs do not synchronize with the base station. The RNC may communicate with a plurality of UEs through a Node B. In this case, the UE may use its own scrambling code so that the Node B can distinguish each of the signals of the UEs. The UE itself scrambles data to be transmitted and transmits the reverse link signal.

In FIG. 1, the structure of the UTRAN is schematically described, and the structure of the UTRAN will be described in detail with reference to FIG. 2.

2 is a diagram illustrating a structure of a UTRAN of a conventional code division multiple access communication system.

Referring to FIG. 2, one UE 211 is connected to the UTRAN. The RNC 1 215 forming a connection between the UE 211 and the Core Network 213 is called a Serving RNC (hereinafter referred to as "SRNC") and is connected to the RNC 1 215. Help RNC 2 217 is referred to as Drift RNC (hereinafter referred to as "DRNC"). FIG. 2 illustrates a state in which the UE 211 establishes four cells and a radio link (hereinafter referred to as a "Radio Link"). In this way, the UE 211 has a plurality of cells, that is, a cell 1 219, a cell 2 221, a cell 3 223, and a cell 4 225. ) And the state in which the radio link is established exist in the handover area, and the UE 211 is in the handover state. Cell 1 219 having the Radio Link with the UE 211 is in Node B 1 227 and Cell 2 221 and Cell 3 223 are in Node B 2 229 and Cell 4 225. ) Is in Node B 3 (231). In FIG. 2, RNC 1 215 and RNC 2 217 are base station controllers, and Node Bs are base stations.

Next, handover of the UE in the UTRAN structure will be described with reference to FIG. 3.

FIG. 3 is a diagram schematically illustrating a handover of a user terminal (UE) in a code division multiple access communication system. In particular, FIG. 3 is a diagram schematically illustrating a case in which the user terminal performs handover to different RNC cells.

Referring to FIG. 3, the UE 211 is a cell in the RNC 1 215, which is an SRNC, that is, a cell 1 (Cell 1) 219, a cell 2 (Cell 2 221, a cell 3) ( 223) and setting up a new Radio Link with Cell 4 (225) in RNC 2 217, which is a DRNC, and performing a handover while setting Radio Link. The message required in the handover process to my cell is as follows: First, the SRNC (RNC 1) 215, which has received information on a basic measurement value for handover from the UE 211, performs handover. After the implementation is decided, a Radio Network Subsystem Application Part message (hereinafter referred to as an "RNSAP message") is transmitted to the DRNC (RNC 2) 217. The RNSAP message is a RADIO LINK SETUP REQUEST message. DRNC (RNC 2) 217 responds to the RADIO LINK SETUP REQUEST message as it receives the RADIO LINK SETUP REQUEST message. The RADIO LINK SETUP RESPONSE message is transmitted to the SRNC (RNC 1) 215.

Hand of the UE 211 between the SRNC (RNC 1) 215 and the DRNC (RNC 2) 217 with the RADIO LINK SETUP REQUEST message and a RADIO LINK SETUP RESPONSE message which is a response message to the RADIO LINK SETUP REQUEST message. Over will be performed. However, unlike the conventional 2nd Generation or 2.5th Generation code division multiple access communication systems, the code division multiple access communication system described with reference to FIGS. It is impossible to provide directly. That is, in order for the UE to handover from the SRNC to the DRNC, the DRNC must detect all the information necessary for the handover with only the information included in the RADIO LINK SETUP RESPONSE message transmitted from the SRNC. There is a need for a method for detecting information necessary for the handover using only information included in a RADIO LINK SETUP REQUEST message.

Accordingly, an object of the present invention is to provide a method for determining a service type when handing over to a different wireless network controller in a mobile communication system.

In order to achieve the above object, the present invention provides a method for determining a service type during handover in a mobile communication system, wherein a user terminal currently communicating with a first base station controller performs a handover to an arbitrary second base station controller. And upon detecting, the first base station controller transmits a radio link setup request message to the second base station controller, and the second base station controller receiving the radio link setup request message is included in the radio link setup request message. Detecting the number of available dedicated channel groups, detecting radio bearers having the detected number of available dedicated channel groups and a minimum error value, and determining a service type of the user terminal using the detected radio bearers Characterized in that it comprises a.

1 is a schematic diagram of a typical code division multiple access communication system.

2 is a diagram showing the structure of UTRAN in a typical code division multiple access communication system;

FIG. 3 schematically illustrates a handover of a UE in a code division multiple access communication system.

4 is a diagram illustrating a process of transmitting messages required for handover to different wireless network controllers in a code division multiple access communication system;

5 is a flowchart illustrating a service type determination process during handover according to an embodiment of the present invention.

6 is a flowchart illustrating a procedure of calculating a radio bearer error value of FIG. 5.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that in the following description, only parts necessary for understanding the operation according to the present invention will be described, and descriptions of other parts will be omitted so as not to distract from the gist of the present invention.

4 is a diagram illustrating a process of transmitting messages required for handover to different wireless network controllers in a code division multiple access communication system.

First, as described above with reference to FIGS. 1 to 3, when a user terminal (UE) is handed over to a different radio network controller (RNC), that is, from SRNC to DRNC, the SRNC sends a RADIO to the DRNC which is an RNSAP message. A LINK SETUP REQUEST message is transmitted, and the DRNC transmits a RADIO LINK SETUP RESPONSE message, which is a response message to the RADIO LINK SETUP REQUEST message, to the SRNC. Here, the SRNC detects a radio bearer (RB: radio channel) most suitable for handover of the UE by using the information included in the RADIO LINK SETUP REQUEST message. In this case, the information necessary for the DRNC to allocate a channel is included in the RADIO LINK SETUP REQUEST message, and the information necessary for determining the service type in the DRNC includes the number of available dedicated channel groups and the available dedicated channel. Number of Dedicated Channels (DCH) per Coordinated DCH Group, Transport Format Set (TFS) for each Dedicated Channel (DCH) (Transport Block), Transport Block Size , A transmission time interval (TTI), etc. Here, the service type is a combination of radio bearers to be currently serviced by the DRNC.

A radio bearer that provides a specific service usually consists of one dedicated channel, but in the case of voice data, three dedicated channels constitute one radio bearer. That is, the three dedicated channels are combined into one radio bearer. Therefore, the serviced radio bearer is represented as one of the available dedicated channel groups (Coordinated DCH groups) received from the RADIO LINK SETUP REQUEST message. As a result, the number of available dedicated channel groups (Coordinated DCH groups) can be interpreted as the number of radio bearers in the DRNC. For example, if a voice service is provided, the radio bearers for the voice service may include a signaling radio bearer (Signalling RB) through which a control signal for the voice service is transmitted, and a traffic radio bearer (or radio) through which voice data is transmitted. It consists of two Radio Access Bearers (RABs). Accordingly, the number of available dedicated channel groups (Coordinated DCH groups) is also delivered in two RADIO LINK SETUP REQUEST messages transmitted by the SRNC to the DRNC.

Then, the DRNC detects the radio bearers most similar to each available Coordinated DCH group, and the detected radio bearers become a service type. If the detected radio bearers are a signaling radio bearer, a voice radio bearer and a packet voice bearer, the service provided is a voice + packet service. Here, the parameters used to detect a radio bearer most similar to the Coordinated DCH group may include the number of Dedicated Channels (DCHs) per Coordinated DCH group, and each Dedicated Channel ( DCH) is a transport format set (TFS).

That is, the DRNC may include information included in the RADIO LINK SETUP REQUEST message received from the SRNC, that is, the number of dedicated channels (DCH) per available coordinated DCH group and the radio bearer internally held by the DRNC. By comparing the information of the two to configure the candidate set of radio bearers having the same number of dedicated channels (DCH). If there is more than one element of the candidate set, the transport format set information of each dedicated channel (DCH) is compared to detect a radio bearer most similar to the available dedicated channel group, that is, the least difference. In detecting the most similar radio bearer, the number of transport blocks, the size of transport blocks, and a transmission time period are compared with each other. If a radio bearer is composed of N dedicated channels, Error_rbi, which is an error value (Error Value) of the i-th candidate radio bearer, may be expressed by Equation 1 below.

The error value E_n of the nth dedicated channel in Equation 1 is expressed as Equation 2 below.

In Equation 2, MAX (NUM_TFI_DB_DCHn, NUM_TFI_Rcv_DCHn) is the number of transport format indicators (TFIs) of the dynamic part of the database and the received nth dedicated channel transport format set. The largest value. TB_number_DBn, t is the number of transport blocks of the transport format indication (TFI) in the n-th dedicated channel (DCH) of the radio bearer stored in the DB, and TB_number_Rcvn, t is the number of TBs included in the received message. TB_size_DBn, t and TB_size_Rcvn, t are the DRNC DB and the received transport block size, respectively. TTI_DBn and TTI_Rcvn are transmission time periods of the semi-static part of the nth dedicated channel transport format set. Also, α, β, and γ are weighting factors of the respective parts.

After calculating Error_rbi values for all radio bearers in the candidate set as described above, the radio bearer having the minimum error value is selected. When the above operation is performed for all available dedicated channel groups, all radio bearers to be serviced can be extracted and determined, and the combination becomes a service type.

Next, a process of determining a service type by the DRNC will be described with reference to FIG. 5.

5 is a flowchart illustrating a service type determination process during handover according to an embodiment of the present invention.

As described in FIG. 3, when the UE 211 hands over from the SRNC 215 to the DRNC 217, the SRNC 215 transmits a RADIO LINK SETUPREQUEST message, which is an RNSAP message, to the DRNC 217, and 511. In step DRNC 217 receives the RADIO LINK SETUP REQUEST message and proceeds to step 513. In step 513, the DRNC 217 calculates the number of available dedicated channel groups and proceeds to step 515. Here, the calculated number of available dedicated channel groups is MAX_RB, and the number of available dedicated channel groups is the number of available dedicated channel groups included in the RADIO LINK SETUP REQUEST message.

In step 515, the DRNC 217 sets the service type value svc of the SRNC 215 to 0 (svc = 0) and proceeds to step 517. In step 517, the DRNC 217 sets the number of available dedicated channel groups as a variable j, sets the number of available dedicated channel groups j to 0, and proceeds to step 519. In step 519, the DRNC 217 calculates the number of dedicated channels of the available dedicated channel group j and proceeds to step 521. Here, the number of dedicated channels of the available dedicated channel group j is set to the variable N. In step 521, the DRNC 217 sets idx to 0 and then proceeds to step 523. In step 523, the DRNC 217 sets the variable k, sets the variable value k to 0, and then proceeds to step 525. In step 525, the DRNC 217 checks whether there is a radio bearer having the same number of dedicated channels as the number N of the available dedicated channel groups by using the radio bearer information stored in the database. If there is a radio bearer having the same number of dedicated channels as the number N of the available dedicated channel groups among the radio bearers stored in the database, the DRNC 217 proceeds to step 527. In step 527, the DRNC 217 stores the radio bearers having the same number of dedicated channels as the number N of the available available dedicated channel groups in the radio bearer candidate set table, that is, RB_CANDIDATE [idx], and then proceeds to step 531. .

On the other hand, if there is no radio bearer having the same number of dedicated channels as the number N of the available dedicated channel groups among the radio bearers stored in the database, the DRNC 217 proceeds to step 529. Proceed. In step 529, the DRNC 217 performs a loop on the variable k value, that is, returns to step 523 and proceeds to step 531. In step 531, the DRNC 217 checks whether the value of the variable value idx is zero. If the value of the variable idx is 0 as a result of the check, the DRNC 217 proceeds to step 533. In step 533, the DRNC 217 determines that an error has occurred in the process of determining a service type of the UE 211, and ends.

On the other hand, if the value of the variable idx is not 0 in step 531, the DRNC 217 proceeds to step 535. In step 535, the DRNC 217 checks whether the value of the variable value idx is 1. If the result of the check is that the value of the variable value idx is 1, the DRNC 217 proceeds to step 537. In step 537, the DRNC 217 selects a service indicated by the jth available dedicated channel group as a radio bearer stored in the candidate set, and proceeds to step 545.

If the value of the variable idx is not 1 in step 535, the DRNC 217 proceeds to step 539. In step 539, the DRNC 217 calculates an error value for all radio bearers in the radio bearer candidate set, and then proceeds to step 541. In step 541, the DRNC 217 determines the service type of the radio bearers as the radio bearer having the minimum error value among the calculated error values, and then proceeds to step 543. In step 543, the DRNC 217 performs a loop on the variable j and proceeds to step 545. In this case, performing the loop on the variable j means that the process returns to the step 517 and re-progresses in step 543. In step 545, if the radio bearer is selected for all available dedicated channel groups, the DRNC 217 determines the service type as a combination of the radio bearers and ends.

Next, the radio bearer error value calculation process described with reference to FIG. 5 will be described with reference to FIG. 6.

6 is a flowchart illustrating a procedure of calculating a radio bearer error value of FIG. 5.

Referring to FIG. 6, in step 611, the DRNC 217 sets the variable value i and proceeds to step 613. Herein, the variable value i is set smaller than the variable value idx of FIG. 5 (i = 0; i <idx; i ++). In step 613, the DRNC 217 sets the variable value p to the i-th radio bearer candidate set, that is, RB_CANDIDATE [i], and sets the error value ERROR_RB [i] of the i-th radio bearer to 0. Proceed to In step 615, the DRNC 217 selects the i-th radio bearer of the radio bearer candidate set RB_CANDIDATE table, initializes it to n = 0, and then proceeds to step 617. In step 617, the DRNC 217 sets Error_TB_num and Error_TB_size to 0 and proceeds to step 619 (Error_TB_num = Error_TB_size = 0). In step 619, the DRNC 217 sets LOOP = MAX (NUM_TFI_DB_DCH _n , NUM_TFI_RCV_DCH _n ) and proceeds to step 621. In step 621, the DRNC 217 sets the variable value t to 0 and then proceeds to step 623. Herein, the variable value t is set smaller than the LOOP value (t = 0; t <LOOP; t ++).

In step 623, the DRNC 217 obtains the difference in the number of t-th TBs of the dynamic part of the n-th dedicated channel (DCH), multiplies the weight α, and adds the result to Error_TB_num to proceed to step 625. In step 625, the DRNC 217 obtains the difference in the size of the t-th TB of the dynamic part of the n-th dedicated channel (DCH), multiplies the weight β, and adds the result to Error_TB_size. In step 627, the DRNC 217 performs a loop on t and proceeds to step 629. In this case, performing the loop on t means increasing t = t + 1 and continuing t steps 623 to 625 unless t exceeds MAX (NUM_TFI_DB_DCHn, NUM_TFI_RCV_DCHn). (NUM_TFI_DB_DCHn, NUM_TFI_RCV_DCHn: TFI number of DB and nth DCH received)

In step 629, the DRNC 217 obtains the difference in the TTI of the nth dedicated channel (DCH), multiplies the weight γ, and proceeds to step 631. In step 631, the DRNC 217 stores the result obtained in step 631 together with ERROR_TB_num and ERROR_TB_size in ERROR_rbi and proceeds to step 633. In step 633, the DRNC 217 performs a loop on n and proceeds to step 635. In step 635, the DRNC 217 ends after performing the loop for i.

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 defined not only by the scope of the following claims, but also by the equivalents of the claims.

As described above, the present invention enables a user terminal to identify a service type for the user terminal when the user terminal is handed over to a different wireless network controller, that is, when the user terminal is handed over from the SRNC to the DRNC. Has an advantage.

Claims (3)

In the method of determining the service type in the handover in the mobile communication system, If the user terminal currently communicating with the first base station controller detects a handover to any second base station controller, the first base station controller transmits a radio link setup request message to the second base station controller; Receiving the radio link setup request message, the second base station controller detecting the number of available dedicated channel groups included in the radio link setup request message; Detecting radio bearers having the detected number of available dedicated channel groups and a minimum error value; And determining a service type of the user terminal using the detected radio bearers. The method of claim 1, The service type is a combination of the radio bearers. The method of claim 1, The number of radio bearers is equal to the number of available dedicated channel groups.