KR20080021240A - Method and apparatus for setting up a call in a mobile communication system - Google Patents

Abstract

A call setup method in a mobile communication system and a device thereof are provided to change a channel if newly calculated activation time expires, when a response is not received from a UE(User Equipment) in the mobile communication system, thereby increasing a call setup success rate. An RB(Radio Bearer) setup message including radio link configuration information and activation time indicative of a time for changing a radio link configuration is transmitted to a UE through a base station(401,403). It is confirmed whether a response message for the setup message is received from the UE(405). If not, the setup message is retransmitted(407). If the response message is not received from the UE, the base station re-determines activation time indicative of a time for changing a configuration of a radio link, and transmits a radio link reconfiguration command message to the base station(409-413). If an RB setup complete message is received from the UE, a response message for the complete message is transmitted to the UE(415,417).

Description

Method and apparatus for setting up call in mobile communication system {Method and Apparatus for setting up a call in a mobile communication system}

1 is a diagram illustrating a radio access bearer setup procedure in a mobile communication system of the WCDA scheme.

2 is a simplified block diagram of a mobile communication system according to a preferred embodiment of the present invention.

3 is a flowchart illustrating a radio bearer setup procedure according to a preferred embodiment of the present invention.

4 is a flow chart illustrating a radio access bearer setup procedure in an RNC in accordance with a preferred embodiment of the present invention.

5 is a flowchart illustrating a radio access bearer setup procedure in a UE according to a preferred embodiment of the present invention.

The present invention relates to call setup in a mobile communication system, and more particularly, to a method and apparatus for increasing a call setup success rate between a terminal and a base station for providing a user service.

In a mobile communication system, in order to communicate between a terminal and a terminal or between a terminal and a service network, a call setup process for establishing channels is required. In addition, the contents necessary for the call establishment process are set as standards according to mobile communication technologies.

In the Wideband Code Division Multiple Access (WCDMA) technology, which is a mobile communication technology widely used worldwide in 3rd generation or 3.5th generation, the standard for the call setup is determined and the standard is applied during the call setup process. It is recommended to use. However, unlike the synchronous mobile communication method (eg, CDMA method), which is mainly used in Korea, the WCDMA method, called the European type method, defines procedures required for call setup and describes several examples of use. Although it is, much depends on the implementation.

A typical call setup procedure in the WCDMA scheme will be described in detail with reference to the accompanying drawings.

FIG. 1 is a diagram illustrating a procedure for establishing a radio access bearer (hereinafter referred to as RAB) in a WCDA-type mobile communication system. In the WCDMA method, a step for establishing a call is set to a radio section access path for transmitting radio resource control (hereinafter referred to as RRC) information and a service access for setting a radio access bearer (RAB). It is recommended to set up by separating the steps and performing the procedure in step 2. 1 illustrates a procedure for setting a RAB, which is a service access path, and conforms to the WCDMA standard.

Referring to FIG. 1, in step 105, a switching network (Core Network, hereinafter referred to as CN) 104 that receives a call request to a user equipment (User Equipment, hereinafter referred to as UE) 101 is RANAP (Radio Access Network Application Protocol). RAB Assignment Request (RAB Assignment Request) message to the radio network controller (Radio Network Controller (hereinafter referred to as RNC)) (103). By doing this, you start setting up RAB. Here, the RAB refers to a transmission path used for transmitting user service data over the UE 101, the base station (Node B) 102, the RNC 103, and the CN 104. The UE (101) and the base station (102), between the UE (101) and the RNC 103 (Uu) is a radio section, between the base station 102 and the RNC 103 (lub), the RNC 103 and CN ( 104. The lu is a streamlined section. The RNC 103 is responsible for the control of all sections of the wired / wired section to set the RAB.

After receiving the RAB allocation request message in step 107, the RNC 103 transmits a Radio Link Reconfiguration Prepare message to the base station 102 by using a Node B Application Part (NBAP) for RAB configuration. The radio link reconfiguration ready message includes radio link (channel) information for use in data transmission between the base station 102 and the UE 101.

The base station 102 obtains information on a radio link setting for supporting a corresponding user service through the radio link reconfiguration preparation message. When the preparation for the radio link setting is completed, such as allocating resources included in the message using the obtained information, in step 109, the base station 102 is ready for radio link reconfiguration using the NBAP (Radio Link Reconfiguration). Ready) message is sent to the RNC 103.

Since the RNC 103 has received the radio link reconfiguration ready message from the base station 120, in step 110, the RNC 103 uses a lucap data transmission bearer using an Access Link Control Application Part (ALCAP) protocol. Start setting of bearer). The lu data transmission bearer setup is not necessary for a packet related service.

In step 111, the RNC 103 starts setting up the Iub data transmission bearer using the ALCAP protocol. In step 111, the RNC 103 includes a binding identifier for interworking the Iub data transmission bearer with a dedicated channel (hereinafter referred to as DCH).

In step 113, the RNC 103 forwards downlink synchronization to the base station 102 using the DCH frame protocol (hereinafter referred to as FP) to provide synchronization information between the RNC 103 and the base station 102. Send a message.

In step 115, the base station 102 transmits an uplink synchronization message to the RNC 103 in response to the forward synchronization message, thereby transmitting an Iub data transmission bearer between the RNC 103 and the base station 102. Set the synchronization.

When the preparation for setting the Iub data transmission bearer is completed, in step 117, the RNC 103 transmits an RRC Radio Bearer Setup message to the UE 101 through the base station 102 in a DCH, in particular, a dedicated control. A channel is transmitted through a dedicated control channel (hereinafter referred to as DCCH).

In step 119, the RNC 103 determines an activation time which is a change synchronization time in radio link reconfiguration for RAB configuration, and uses a radio link reconfiguration command to the base station 102 using the NBAP. The message includes information on the active time and radio link reconfiguration information.

The base station 102 and the UE 101 that have received the information on the activation time change the radio link environment to RAB to enable user service when the activation time expires. In step 121, the UE 101 acquires synchronization in the changed radio link environment and transmits an RRC Radio Bearer Setup Complete message to the RNC 103 indicating that RB setup is successful.

When the RNC 103 receives the radio bearer setup complete message, the RNC 103 responds to the RAB assignment request message received in step 105 using RANAP to the CN 104 in step 123. Response), indicating that the RAB setup was successful.

By doing so, in step 123, an RAB capable of performing a call request to the UE 101 is set, and a procedure for call setup of the UE 101 is completed.

The above-described procedures have no problem when the state of the wireless environment is good, but an error may occur when the state of the wireless environment is not good. In order to solve this problem, when an error occurs in a part of the RRC radio bearer setup message using a Radio Link Control (hereinafter referred to as RLC) protocol, the radio bearer setup message is retransmitted. A method for eliminating the error for has been proposed. However, this method is only possible before the active time expires. In detail, even if the radio bearer setup message is not transmitted from the RNC to the UE when the active time expires, the base station changes the channel, that is, the radio link setup to provide the requested service, so that the radio bearer setup message is eventually It is not sent to the UE.

To compensate for this, the proposed technology first transmits the radio bearer (hereinafter referred to as RB) configuration message to the UE, receives an RLC response message (hereinafter referred to as RLC acknowledgment) for the channel information of the base station. Algorithm to change the. However, even in this method, when the state of the downlink channel is good when the RB configuration message is transmitted but the state of the uplink channel is not good, the RLC acknowledgment is not normally transmitted from the UE to the RNC. Do not send a message to change. Therefore, even if the activation time expires, the base station does not change the channel. However, at this time, if the UE has already successfully received the RRC RB setup message, the UE changes the channel when the active time expires. Therefore, even if the UE whose channel is changed retransmits the RRC RB establishment complete message to the reverse channel, the RNC cannot receive the RRC RB establishment complete message. Therefore, such a situation leads to a call setup failure, thereby causing a problem that the call setup success rate decreases.

Accordingly, the present invention proposes a method and apparatus for increasing the success rate of call setup in a mobile communication system.

In addition, the present invention proposes a method and apparatus for increasing a call establishment success rate by changing a channel when a newly calculated active time expires when a mobile communication system does not receive a response from a UE.

According to one aspect of the preferred embodiment of the present invention, in a mobile communication system including a control station for controlling communication between a terminal and a base station of the present invention, a call setup method by a control station is a time for changing a radio link configuration for call setup. Transmitting a radio bearer setup message including an activation time and radio link configuration information to the terminal through the base station, and confirming whether a response message for the radio bearer setup message is received from the terminal; And if the response message is not received from the terminal, retransmitting the radio bearer setup message within a predetermined maximum number of times, and if the response message is not received from the terminal even after the retransmission, Indicates the time to change the configuration of the radio link Re-determining an active time and transmitting a radio link reconfiguration command message including the re-established active time and the radio link configuration information to the base station; and receiving a radio bearer setup complete message indicating that the radio link configuration is changed from the terminal. When receiving, the method includes transmitting a response message to the terminal to the radio bearer setup complete message.

According to another aspect of the preferred embodiment of the present invention, the mobile communication system of the present invention transmits a radio bearer setup message including an activation time and radio link configuration information indicating a time for changing the radio link configuration for call setup. When transmitting to the terminal through a base station, and confirming that the response message for the radio bearer setup message is received from the terminal, and if the response message is not received from the terminal, the radio bearer setup message within a predetermined maximum number of times A control station for retransmitting, if the response message is not received from the terminal even after the retransmission, re-determining the active time and transmitting a radio link reconfiguration command message including the re-established active time and the radio link configuration information to the base station; To the control station A base station that receives the radio link reconfiguration command message and changes the radio link configuration according to the radio link configuration information included in the radio link reconfiguration command message when the active time included in the radio link reconfiguration command message expires. And receiving the radio bearer setup message from the control station through the base station, transmitting a response message to the radio bearer setup message to the control station, and when the active time expires, changes the radio link configuration. And a terminal for transmitting the radio bearer setup complete message to the control station.

The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that those skilled in the art may better understand it from the following detailed description of the invention. In addition to these features and advantages, further features and advantages of the present invention which form the subject of the claims of the present invention will be better understood from the following detailed description of the invention.

DETAILED DESCRIPTION A detailed description of preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art will recognize that the disclosed concept and specific embodiments of the invention described below may be changed or modified to achieve the technical problem to be achieved by the present invention. Those skilled in the art will also recognize that concepts and structures equivalent to the concepts and structures disclosed herein do not depart from the spirit and scope of the broadest form of the invention. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

2 is a simplified block diagram of a mobile communication system according to a preferred embodiment of the present invention. For convenience of description, FIG. 2 illustrates a configuration diagram of the UMTS system in the mobile communication system. However, the present invention can be applied to other mobile communication systems as well as the UMTS system.

Referring to FIG. 2, UE1 201 is wirelessly connected to Node B1 205. Multiple UEs may be connected to one Node B. The RNC1 210, which is wired to the Node B1 205, may be connected to a plurality of Node Bs including the Node B1 205. In FIG. 2, only the connections between the RNC1 210, the Node B1 205, and the Node B2 206 among the Node Bs are illustrated.

In addition, UE2 202 is wirelessly connected to Node B3 207, and Node B3 207 is connected to RNC2 211 by wire.

The RNCs 210 and 211 allocate or manage radio resources of Node Bs 205 to 207 that they control. Node Bs 205 through 207 serve to provide actual radio resources. Radio resources are configured for each cell, and radio resources provided by the Node Bs 205 to 207 mean radio resources of cells managed by the nodes. UEs 201 and 202 may configure a radio channel and perform communication using radio resources provided by a specific cell of specific Node Bs 205 and 207.

3 is a flowchart illustrating an RB setup procedure according to a preferred embodiment of the present invention. 3 is a detailed description of operations after operation 115 of FIG. 1.

Referring to FIG. 3, in step 310, the RNC 303 transmits an RB configuration message to the UE 301 via the Node B 302. In this case, the RB configuration message includes active time information, which is a channel change synchronization time, and the UE 301 changes a channel when the active time expires.

In step 312, the UE 301 receives the RB configuration message and transmits an RLC acknowledgment to the RNC 303 in response to the RB configuration message. However, at this time, the uplink channel state is not good and the RLC acknowledgment is not normally received from the UE 301 to the RNC 303. The RNC 303 then retransmits the RB configuration message as many times as the predetermined number of retransmissions. Nevertheless, if no RLC acknowledgment is received, the RNC 303 determines the minimum active time for the Node B 302 and forwards it to the Node B 302 so that the base station immediately channels at the time that the active time expires. To change.

In other words, when the RNC 303 does not receive the RLC acknowledgment from the UE 301 and it is not known whether the UE 301 has received all of the RRC RB setup messages, the RNC 303 determines the maximum number of retransmissions in step 314. Perform retransmission as much as possible. The maximum number of retransmissions is the number of times the UE 301 can assume that it has successfully received the RRC RB setup message from the RNC 303.

When the RRC RB setup message is retransmitted by the maximum number of retransmissions, the RNC 303 considers that the UE 301 has received the RRC RB setup message, and performs a channel change of the Node B 302 in step 316. The indicated radio link reconfiguration command message is transmitted to the Node B 302 using the NBAP. The radio link reconfiguration command message includes an activation time re-determined by the RNC 303. The re-determined active time is the minimum time value at which Node B 302 can change the channel. Upon receiving the radio link reconfiguration command message, the Node B 302 changes the channel configuration immediately at the time when the active time expires according to the information included in the radio link reconfiguration command message. In this way, the channel configuration of the UE 301 and the channel configuration of the Node B 302 may be matched to transmit and receive a message between the UE 301 and the RNC 303.

If the activation time according to the activation time information included in the RB configuration message received in step 310 and step 314 expires, the UE 301 changes the channel configuration, and then completes RRC RB setup through the changed channel in step 318. The message is sent to the RNC 303 via the Node B 302. As described above, the timing at which the UE 301 changes the channel configuration and the timing at which the Node B 302 changes the channel configuration may be different. That is, when the reverse radio environment is not good, the UE 301 may change the channel configuration first, and later the Node B 302 may change the channel configuration. In this case, the UE 301 first changes the channel configuration, and then continuously transmits an RRC RB setup complete message to the RNC 303 until the maximum number of transmissions is reached. When the Node B 302 changes the channel configuration, the UE 301 can receive the RRC RB setup complete message that the UE 301 continues to transmit, and can be delivered to the RNC 303.

 Although not shown, when the RNC 303 receives the RRC RB setup complete message, the RNC 303 transmits an RLC acknowledgment (hereinafter, referred to as a DL RLC acknowledgment) through a forward channel in response to the RB setup complete message. However, if there is no DL RLC acknowledgment from the RNC 303, the UE 301 retransmits an RRC RB setup complete message until the RNC 303 can receive it. Here, the maximum time for the UE 301 to retransmit the RRC RB setup complete message over the reverse channel, Node B (at the maximum time for the RNC 303 to retransmit the RRC RB setup message over the forward channel in step 314 302 is greater than the sum of the times when the active time for changing the channel configuration expires. That is, it is determined as '(maximum reverse retransmission time)> (maximum forward retransmission time) + (Node B active time expiry time)'. By setting each retransmission maximum time value, the UE 301 retransmits the RRC RB setup complete message so that the Node B 302 can change the channel. The maximum length of reverse retransmission means a time taken for the UE 301 to transmit an RRL RB setup complete message to the RNC 303 a maximum number of times, and the maximum time for forward retransmission means that the RNC 303 sends an RRC RB setup message to the UE. It means the time it takes to transmit the maximum number of times to (301).

 Operations of the RNC and the UE in the RAB configuration process will be described in detail with reference to FIGS. 4 and 5.

4 is a flowchart illustrating a RAB setup procedure in an RNC according to a preferred embodiment of the present invention.

Referring to FIG. 4, in step 401, the time until the RNC 303 of FIG. 3 changes the channel configuration between the UE 301 and the Node B 302 is determined.

In step 403, the RNC 303 transmits an RB configuration message including information on the active time (ie, active time information) to the UE 301 through the Node B 302.

In step 405, the RNC 303 checks whether a response message (RLC Ack) to the transmitted RB setup message is received from the UE 301. If the response message is received, go to step 415, and if the response message is not received, go to step 407.

In step 407, the RNC 303 retransmits the RB setup message to the UE 301 in case the UE 301 does not receive the RB setup message.

In step 409, the RNC 303 checks whether the RB configuration message has been retransmitted up to a predetermined number of retransmissions. If the RB setup message has been retransmitted the maximum number of retransmissions, the process proceeds to step 411. If the RB configuration message has not been retransmitted the maximum number of retransmissions, the process returns to step 405.

If the RNC 303 does not receive the RLC acknowledgment from the UE 301 even though the RB setup message has been retransmitted the maximum number of times, the RNC 303 may change the channel configuration of the Node B 302 in step 411. Re-determine the active time so that Here, since the RNC 303 retransmitted the RB configuration message by the maximum number of retransmissions that the UE 301 may have regarded as having normally received the RB configuration message, the RNC 303 may not be in a reverse channel state. The RLC acknowledgment is not received from the UE 301 and the active time is re-determined to change the channel of the Node B 302.

In step 413, the RB bearer setup message including the active time information determined in step 401 or the radio link reconfiguration command message including the active time information re-determined in step 411 is transmitted to the Node B 302. Here, the Node B 302 receiving the message changes the channel configuration according to the radio link information included in the message at the time when the provided active time expires.

In step 415, the RNC 303 receives the RB setup complete message from the UE 301 through the changed channel.

In step 417, the RNC 303 transmits a response message (hereinafter referred to as DL RLC Ack) to the UE 301 in response to the received RB setup complete message.

In accordance with the procedure described above in step 419, the RNC 303 completes the RAB establishment with the UE 301 through the Node B 302.

By doing so, the present invention, when the UE has normally received the RB setup message but the reverse channel state is not good, so that the UE does not receive a response message for the RB setup message, only the UE changes the channel configuration according to the radio link information and Node B Can resolve the failure of call setup caused by not changing the channel configuration.

5 is a flowchart illustrating a RAB setup procedure in a UE according to a preferred embodiment of the present invention.

Referring to FIG. 5, in operation 501, the UE 301 of FIG. 3 receives an RB configuration message from the RNC 303.

In step 503, the UE 301 transmits an RLC Ack through the Node B 302 to the RNC 303 on a reverse channel in response to the received RB setup message.

In step 505, the UE 301 checks whether the provided activation time according to the activation time information included in the received RB configuration message expires. If the activation time has expired, the process proceeds to step 509. If the activation time has not expired, the process proceeds to step 507.

In step 507, the UE 301 checks whether the RB configuration message is re-received from the RNC 303. If the RB setup message is received again, the UE 301 returns to step 503 to retransmit the response message to the message. If the RB setup message is not received again, the UE 301 returns to step 505 to check whether the active time, which is time to change the channel configuration, expires.

When the activation time, which is the channel configuration change time, expires, in step 509, the UE 301 changes the channel configuration according to the radio link information included in the received RB setup message, and then an RB setup complete message indicating that the RB setup is completed. Is transmitted to the RNC 303 through the Node B 302.

In step 511, the UE 301 checks whether it receives a response message (hereinafter, referred to as DL RLC acknowledgment) from the RNC 303 in response to the RB setup complete message. If the DL RLC Ack is received from the RCN 303, the method proceeds to step 517. If the DL RLC Ack is not received, the flow proceeds to step 513.

In step 513, the UE 301 checks whether the RB configuration complete message has been retransmitted a predetermined maximum number of times. If the message has been retransmitted up to the maximum number of times, even if the DL RLC acknowledgment is not received, the RAB setup is considered complete and the process proceeds to step 515. If the message has not been retransmitted the maximum number of times, the process returns to step 509.

In step 515, the UE 301 completes RAB establishment with the RNC 303 via the Node B 302.

By doing so, the operation of the UE is completed in establishing a connection path for communication between the UE, the Node B, and the RNC.

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 those equivalent to the scope of the claims.

As described above, in the present invention, when the RNC has not received the response message from the UE even though the RNC has transmitted the radio bearer setup message up to the maximum number of times in the WCDMA radio access technology, the RNC immediately changes the configuration of the radio link of Node B. Instructing Node B to do so has the advantage of increasing the call establishment success rate between the UE and RNC.

Claims (9)

In the mobile communication system including a control station for controlling the communication between the terminal and the base station, the call setup method by the control station, Transmitting a radio bearer setup message including an activation time and radio link configuration information indicating a time for changing a radio link configuration for call setup to the terminal through the base station; Checking whether a response message to the radio bearer establishment message is received from the terminal; If the response message is not received from the terminal, retransmitting the radio bearer setup message within a predetermined maximum number of times; If the response message is not received from the terminal even after the retransmission, the base station re-determines an active time indicating a time for changing the configuration of the radio link and includes the re-established active time and the radio link configuration information. Transmitting a command message to the base station; And receiving a radio bearer setup complete message indicating that the radio link configuration is changed from the terminal, and transmitting a response message to the mobile bearer setup complete message to the terminal. 2. The method of claim 1, wherein the re-established active time is a minimum time value at which the base station can change the configuration of the radio link. In the mobile communication system comprising a control station for controlling the communication between the terminal and the base station, the call setup method by the terminal, Receiving a radio bearer setup message including an activation time and radio link configuration information indicating a time for changing a radio link configuration to request a call setup from the control station through the base station; Transmitting a response message to the control station to the radio bearer establishment message; Checking whether the active time expires; Retransmitting a response message to the radio bearer establishment message if the radio bearer establishment message is re-received before the activation time expires; If the activation time expires, changing the radio link configuration, and transmitting a radio bearer setup complete message to the control station. The method of claim 3, wherein after transmitting the radio bearer setup complete message to a control station, Checking whether a response message to the radio bearer setup complete message is received from the control station; If the response message is not received from the control station, retransmitting the radio bearer setup complete message to the control station within a predetermined maximum number of times. The method as claimed in claim 3, wherein the terminal changes the radio link configuration at the time when the activation time expires. In mobile systems, A radio bearer setup message including an activation time and radio link configuration information indicating a time for changing a radio link configuration for call setup is transmitted to a terminal through a base station, and a response message for the radio bearer setup message is transmitted. Check whether it is received from the terminal, if the response message is not received from the terminal, retransmit the radio bearer setup message within a predetermined maximum number of times, and if the response message is not received from the terminal even after the retransmission, the active A control station for re-determining a time to transmit a radio link reconfiguration command message including the re-established active time and the radio link configuration information to the base station; Receiving the radio link reconfiguration command message from the control station, and if the active time included in the radio link reconfiguration command message expires, the radio link configuration according to the radio link configuration information included in the radio link reconfiguration command message. The base station to change, Receiving the radio bearer setup message from the control station through the base station, and transmits a response message to the radio bearer setup message to the control station, if the active time expires, after changing the radio link configuration, And a terminal for transmitting a bearer setup complete message to the control station. 7. The call setup apparatus according to claim 6, wherein the re-established active time is a minimum time value at which the base station can change the configuration of the radio link. 7. The call setup apparatus of claim 6, wherein the terminal changes a radio link configuration when the activation time expires. The method of claim 6, wherein the terminal transmits a radio bearer setup complete message to a control station, and then confirms that a response message to the radio bearer setup complete message is received from the control station, and the response message is received from the control station. And if not received, retransmitting the radio bearer setup complete message to the control station within a predetermined maximum number of times.

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