KR20060010682A - An flc application method that differentiates connected mode ue depending on the radio resource status - Google Patents

Abstract

In a mobile communication system for a multimedia broadcasting / multicast (MBMS) service, an FLC method for moving terminals to a frequency band where a corresponding service is provided, the FLC method for determining a movement to a preferred frequency of a terminal located at a non-preferred frequency Measuring radio resources of a preferred frequency of a service, determining whether the measured radio frequency of the preferred frequency can accommodate related traffic of terminals, and determining whether to apply FLC of the connected mode terminals located at the non-preferred frequency; Transmitting the determined FLC application information to the terminals in the connected mode; if the FLC application information is applied, the connected mode terminal performs the FLC; if the FLC application information is not applied, the current cell Involves performing the service selection process, while maintaining the In this case, even though traffic for a specific service of the connected mode terminal cannot be accommodated at a preferred frequency, the FLC may be prevented from moving to the preferred frequency.

MBMS, FLC (Frequency Layer Convergence), PL (Preferred Layer), NPL (Non Preferred Layer), FLC disabled indication for connected mode UE, flag, bitmap

Description

{An FLC application method that differentiates connected mode UE depending on the radio resource status}             

1 is a diagram illustrating a simplified configuration of a mobile communication system for an MBMS service.

2 is a diagram illustrating an example of a cell layer structure overlapping a region providing the same MBMS service.

3 is a diagram illustrating a procedure for determining whether FLC of a connected mode terminal is applied by an RNC according to an embodiment of the present invention.

4 is a flowchart illustrating an operation of a connected mode terminal to which a method of notifying whether FLC is applied as a flag of one bit is applied according to an exemplary embodiment of the present invention.

5 is a flowchart illustrating an operation of a connected mode terminal to which a method of notifying whether FLC is applied as a flag value of one bit according to another embodiment of the present invention is applied.

6 shows an FLC method according to the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multimedia broadcast / multicast service (hereinafter referred to as an 'MBMS service'). In particular, the FLC (Frequecy Layer Convergence) is differentiated between a connected mode terminal and an idle mode terminal according to a radio resource state. ) Is how to apply.

Today, due to the development of communication technology, the services provided by a mobile communication system using a wideband code division multiple access (CDMA) scheme are not only a conventional voice service but also a large data transfer such as packet data. It is developing into packet service communication and multimedia broadcasting / communication capable of transmitting multimedia service. Accordingly, in order to support the multimedia broadcasting / communication, an MBMS service that provides a service to a plurality of user equipments from one or more multimedia data sources has been discussed.

The MBMS service refers to a service for transmitting the same multimedia data to multiple receivers through a wireless network. In this case, by allowing multiple receivers to share one radio channel, it is possible to save radio transmission resources.

The FLC is a method of moving a terminal to a preferred frequency band for each service in order to provide a service for only one frequency for each service without providing a service for all frequencies overlapping the same region.

When the session of the MBMS service is started, a radio resource management (RRM) determines a Preferred Layer (PL) for the MBMS service. At this time, since the idle mode terminal does not have associated traffic, the network does not affect the system resource situation even when the idle mode terminal joining the service in another frequency band moves to the PL.

However, since the connected mode terminal has associated traffic, it may not be able to move to the PL according to the radio resource availability of the PL. That is, when the radio resource of the PL cannot accommodate the traffic of the connected mode terminal, the specific service of the connected mode terminal is interrupted.

Accordingly, an object of the present invention, which was devised to solve the problems of the prior art operating as described above, is to provide an idle mode terminal and associated traffic when the FLC is applied to a terminal subscribed to an MBMS service. It is to provide a method of discriminating whether to apply FLC.

Another object of the present invention is to provide a method for the network to determine whether to apply the FLC in consideration of the radio resource status of the PL, while the idle mode terminal is mandated to apply the FLC during the session of one MBMS service will be.

Another object of the present invention is to provide a method for transmitting information on whether FLC of the connected mode terminal is applied to the terminal.

Still another object of the present invention is to define an operation of a terminal according to information on whether the signaled connected mode terminal applies FLC in providing the above method.

An embodiment of the present invention, which was devised to achieve the above object, relates to a FLC method for moving terminals to a frequency band where a corresponding service is provided in a mobile communication system for a multimedia broadcasting / multicast (MBMS) service. In

Measuring a radio resource of a preferred frequency for the service to determine movement of a terminal located at a non-preferred frequency to a preferred frequency;

Determining whether to apply FLC (Frequency Layer Convergence) of terminals located at the non-preferred frequency as the radio resource of the measured preferred frequency;

And transmitting the determined FLC application information to the terminals.

An embodiment of the present invention, which was created to achieve the above object, relates to a FLC method for moving a terminal to a frequency band where a corresponding service is provided in a mobile communication system for a multimedia broadcasting / multicast (MBMS) service. In

Receiving a FLC notification message related to whether FLC (Frequency Layer Convergence) is applied from a radio network controller (RNC);

Checking whether the terminal receives the FLC and whether the terminal is located at a non-preferred frequency;                         

If the terminal is applied to the FLC and located in the cell of the non-preferred frequency, it comprises a step of performing a cell reselection to the cell of the preferred frequency.

In another embodiment of the present invention as described above, in a mobile communication system for a multimedia broadcasting / multicast (MBMS) service, a method for a terminal to move to a frequency band where a corresponding service is provided,

Receiving a FLC notification message related to FLC (Frequency Layer Convergence) availability information from a Radio Network Controller (RNC),

Checking whether the terminal receives the FLC and whether the terminal is located in a cell of a non-preferred frequency;

If the terminal is located in a cell of a non-preferred frequency without applying the FLC, it comprises a process of maintaining the current cell or performing a service selection process.

Hereinafter, with reference to the accompanying drawings will be described in detail the operating principle of the preferred embodiment of the present invention. Like reference numerals are used to designate like elements even though they are shown in different drawings, and detailed descriptions of related well-known functions or configurations are not required to describe the present invention. If it is determined that it can be blurred, the detailed description thereof will be omitted. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

First, the MBMS service applied to the present invention will be described.

1 shows a simplified configuration diagram of a mobile communication system for an MBMS service. Here, an example of applying a MBMS service to a 3GPP (3rd Generation Project Partnership) system, which is a standard of third generation asynchronous mobile communication, is illustrated.

Referring to FIG. 1, UEs 161, 162, 163, 171, and 172 refer to terminal devices or subscribers capable of receiving MBMS services, and are referred to as cell 1 160 and cell 2 170. Is controlled by a base station apparatus, Node B, which wirelessly transmits MBMS related data to subscribers. A Radio Network Controller (RNC) 140 controls the plurality of cells 160 and 170, selectively transmits multimedia data to a specific cell, and is configured to provide MBMS service. Control the wireless channel. The connection between the RNC 140 and the UEs 161-172 is called a Radio Resource Control (RRC) interface.

The RNC 140 is connected to a Packet Switched or Packet Service (PS) network such as the Internet by a Serving GPRS Support Node (hereinafter referred to as 'SGSN') 130. Communication between the RNC 140 and the PS network is made by packet switched signaling (PS signaling). In particular, the connection between the RNC 140 and the SGSN 130 is called an Iu-PS interface.

SGSN 130 controls the MBMS-related services of each subscriber. Representative examples of the role played by the SGSN 130 include managing a service related data of each subscriber and selectively transmitting multimedia data to a specific RNC 140.

The Transit NW 120 provides a communication path between the Broadcast Multicast Service Center (BM-SC) 110 and the SGSN 130 and to an external network through a Gateway GPRS Support Node (GGSN). Can be connected. The BM-SC 110 is responsible for scheduling MBMS data as a source of MBMS data.

 MBMS data streams are delivered to UEs 161, 162, 163, 171 and 172 via the transport network 120, SGSN 130, RNC 140, Node B and cells 160, 170.

Hereinafter, an example of a cell layer structure overlapping an area providing the same MBMS service will be described with reference to FIG. 2.

As shown in FIG. 2, regions covered by a plurality of frequencies, that is, frequency 1 (f1) and frequency 2 (f2), are overlapped in the region A providing a specific MBMS service. One frequency or layer of consecutive cells is called a layer. FLC does not provide a service in all frequencies (f1, f2) overlapping the same region (A), but instead moves a terminal to a corresponding frequency band for each service in order to provide a service in only one frequency for each possible service. Say.

For example, if the layer for a specific service B is f2 in the cell structure of FIG. 2, the terminals in the layer f1 in the region A receive the service B when the session of the service B starts and during the session. In order to perform the cell reselection to the layer of f2. The UTRAN informs the terminals of the f1 to move to the f2 when the session of the service starts and during the session. In this case, f1 is a PL (Preferred Layer) of the service B, and the cell of frequency 2 is a non-preferred layer (NPL).

However, even NPL does not necessarily mean that the service is impossible. The measurement result such as the signal strength of the PL for providing the service is insufficient, so that the service may be provided by RRM (Radio Resource Management) in the NPL for the terminal left in the NPL. In the above description, the PL for the MBMS service is fixed as a layer of frequency 2, but this may be different depending on the region. Typically, you will have the same layer, but for example, in some regions of a region f1 will be PL, while in some regions f2 may be PL. This is because the PL of the MBMS service is determined according to the cell structure policy of the operator and the situation of radio resources of the cell currently being used. In the current 3GPP standard, the FLC structure is applied from the start of one MBMS service session until the end of the session.

When the idle mode terminal is located in the NPL without a connection with the UTRAN, the idle mode terminal may move to the PL regardless of whether the PL is available. However, the connected mode terminal determines whether to move according to the availability of radio resources of the PL in the CELL_FACH, CELL_PCH, URA_PCH, and CELL_DCH states.                     

The CELL_FACH is a state in which a dedicated physical channel is not allocated to a terminal and uses shared transport channels, and the CELL_PCH is a state in which a dedicated physical channel is not allocated to a terminal and a dedicated logical channel is not available. The URA_PCH is almost similar to the CELL_PCH and is used when there is a burden due to a cell update process due to the mobility of the terminal. Finally, the CELL_DCH is in a state in which dedicated physical channels can be used.

The present invention to be described later selects whether to apply the FLC of the connected mode terminal in the mobile communication system providing the MBMS service according to the radio resource state of the PL. To this end, the network performs RRM to determine whether to apply the FLC of the connected mode terminal, and transmits the information on whether the determined FLC is applied to the terminal, and the connected mode terminal receiving the information operates according to the information. .

Hereinafter, an operation of the RNC for determining whether to apply the FLC of the connected mode terminal will be described in detail with reference to FIG. 3.

3 is a diagram illustrating a procedure for determining whether to apply an FLC of a connected mode terminal by an RNC according to the present invention.

Referring to FIG. 3, in step 201, the RNC measures radio resources of the PL in order to determine whether to apply FLC of the UEs in the connected mode located in the NPL.

In step 203, the RNC determines whether the radio resource in the measured PL can accommodate the associated traffic number of the connected mode terminal. This indicates whether the radio resource state for the preferred frequency is sufficient, and the total number of connected mode terminals to receive the service located in NPL to move to the PL or each state among the connected modes (CELL_FACH, CELL_PCH, URA_PCH, CELL_DCH). The number of terminals by) may be considered. Thereafter, if the measured radio resources of the target frequency can accommodate the relevant traffic of the connected mode terminal, it is determined to apply the FLC to the connected mode terminals located in the NPL and proceeds to step 205.

In step 205, the RNC sets a FLC disabled indication for connected mode UE (FLC_DI), which is information indicating whether the FLC is applied, and transmits it to the corresponding UE.

In step 203, if the measured radio resources of the target frequency are not acceptable to the associated traffic of the connected mode terminal, and determines to not apply the FLC to the connected mode terminal located in the NPL proceeds to step 207. In step 207, the RNC sets FLC_DI to 'Y' and transmits it to the corresponding UE.

The information about the FLC-DI may indicate the application of the FLC to the connected mode terminal or the specific RRC state as a flag value of one bit, and separately determine whether to apply the FLC according to each state of the connected mode in the network. It can also be given as a 4-bit bitmap format or as a 2-bit integer representation. For example, if the 4-bit bitmap format is used, the first bit indicates the URA_PCH state, the second bit indicates the CELL_PCH state, the third bit indicates the CELL_FACH state, and the fourth bit indicates the CELL_DCH state to indicate whether FLC is applied. That is, when the FLC_DI value is '0011', the terminal in the CELL_FACH and CELL_DCH states does not apply the FLC, and the terminal in the URA_PCH and CELL_PCH states applies the FLC.

As another example, using a 2-bit integer expression value, 00 may represent CELL_DCH, 01 may represent CELL_FACH, 10 may represent CELL_PCH, and 11 may represent URA_PCH. In this case, if FLC_DI has a value of '01', terminals in CELL_DCH and CELL_FACH states do not apply FLC, and terminals in CELL_PCH and URA_PCH apply FLC.

Hereinafter, the following embodiment of the present invention will be described as a flag of one bit among the methods for indicating the information on the FLC_DI.

Hereinafter, the operation of the connected mode terminal according to the present invention will be described with reference to FIG. 4.

4 is a flowchart illustrating the operation of a connected mode terminal according to an embodiment of the present invention. Here, a case in which the method of notifying whether the connected mode terminal applies the FLC among the FLC methods proposed by the present invention is applied will be described.

Referring to FIG. 4, in step 222, the connected mode terminal receives an FLC notification (FLC_notification) message. The FLC_notification message includes a service ID, PL, MBMS offset, FLC_DI, etc. to perform FLC.

In step 224, the terminal receiving the FLC_notification message checks whether the service ID is a service joined by the connected terminal. If the service ID is not a service joined by the connected terminal, the flow proceeds to step 234 to maintain the current cell without applying the FLC.                     

If the service ID is a service joined by the connected terminal, the flow proceeds to step 226. In step 226, the terminal checks whether the FLC_DI is set to 'N'. If the value of the FLC_DI is set to 'Y', the terminal does not need to apply the FLC and proceeds to step 234. In step 234, the PL stays in the current cell without the need for measuring the PL for the FLC and reselecting the PL. Even if the current cell is NPL, if there are enough available resources, a service to be provided by the terminals may be provided. Whether the service for the NPL can be known by receiving MBMS control information transmitted from the NPL.

In step 226, if the FLC_DI value is set to 'N', the connected mode terminal proceeds to step 228 to determine whether the cell in which the cell is located is NPL. If the determination result is located in the NPL, in step 230, the connected mode terminal performs cell reselection with the PL. If the determination result is not located in the NPL, the process proceeds to step 234 to maintain the current cell.

In step 230, cell reselection to the PL of the connected mode terminal is performed based on the measurement result in the PL included in the FLC_notification received in step 222. In this case, the MBMS offset value is used to reset the cell to the PL. Used as a factor to increase the probability of selection.

In FIG. 4, the case in which the information about the FLC_DI is given as a flag value of one bit indicating that the FLC is applied to the connected mode terminal or a specific RRC state is used. However, according to the state of the connected mode in the network, When determining whether to apply FLC, it may be given as a 4-bit bitmap format or a 2-bit integer representation value.

5 is a flowchart illustrating the operation of a connected mode terminal according to another embodiment of the present invention.

Referring to FIG. 5, in step 302, the connected mode terminal receives an FLC notification message. The FLC_notification message includes a service ID, PL, MBMS offset, FLC_DI, etc. to perform FLC. In step 303, the terminal receiving the FLC_notification message checks whether the service ID is a service joined by the connected terminal. If the service ID is not a service joined by the connected terminal, the process proceeds to step 311 to maintain the current cell without applying the FLC.

If the service ID is a service joined by the connected terminal, the process proceeds to step 312. In step 312, the connected terminal determines whether the current cell is an NPL. If the current cell is not located in the NPL as a result of the determination, the process proceeds to step 311 to maintain the current cell without applying the FLC. If the current cell is located in the NPL as a result of the determination, step 321 is performed.

In step 321, the terminal checks whether the FLC_DI is set to 'N'. If the FLC_DI value is set to 'Y', the terminal proceeds to step 323. In step 323, the terminal selects a service that is selected from the existing service and the MBMS service to apply the FLC included in the FLC_notification message received in step 302. Selection of the service selects a service having a high priority through interaction with a user or a non-access stratum (NAS).

After the service selection, it is checked in step 324 whether the service selection result is an MBMS service for applying the FLC. If the MBMS service for the FLC application is selected as a result of the checking, in step 325, the existing service is canceled or abandoned and the process proceeds to step 322. In step 322, the connected terminal performs an operation of measuring PL for FLC and reselecting to PL based on the measurement result.

If the existing service is selected as a result of confirming the service selection, the process proceeds to step 311 and continues to receive the existing service while maintaining the current cell without applying the FLC.

In FIG. 5, an example of applying a method of notifying whether a connected mode terminal is applied to the FLC by using a flag value of one bit among the FLC application methods proposed by the present invention has been described as an example. However, one bit applied to a specific RRC state is described. In order to determine whether to apply a separate FLC according to the flag value of the connected mode or each connected mode in the network, it may be given as a 4-bit bitmap format or a 2-bit integer representation value.

6 is a view showing an embodiment of a FLC method according to a preferred embodiment of the present invention.

In this case, taking a specific MBMS service as an example, among the frequencies overlapping the same service area, reference numeral 408 denotes a terminal located in an NPL, and reference numeral 409 denotes terminals located in a PL (hereinafter referred to as a PL terminal). The NPL and PL are superimposed on one service area, and reference numeral 210 denotes an RNC for managing radio resources of the NPL and PL for MBMS service.

Referring to FIG. 6, in step 411, the RNC 410 receives a session start message for one session of the service from the SGSN of the core network. The session start message is sent from the SGSN to the RNC by informing it to perform an operation such as establishing a radio bearer for starting a session of the service. The session start message includes a service ID, quality of service (QoS) information, and the like.

In step 421, the RNC 410 receiving the session start message transmits an FLC Notification message to the NPL 408 as signaling for the FLC. The FLC Notification message includes the service ID, PL, MBMS offset, and FLC_DI.

In this case, the service ID indicates a service corresponding to the session, and PL indicates a PL frequency of the service session. The MBMS offset indicates a threshold to be applied to the measurement when the terminal of the NPL reselects to the PL. In addition, the FLC_DI is information on whether the connected mode terminal is applied to the FLC.

In step 431, the NPL connected terminal 208 that receives the FLC Notification message operates according to the FLC_DI value of the received FLC Notification message. If the FLC_DI is 'N', the connected terminal of the NPL performs reselection to the PL according to the measurement result for the PL. If the FLC_DI is 'Y', the connected terminal 208 of the NPL maintains the current cell. In addition, among the currently received service and the MBMS service for FLC application indicated in the FLC notification message, service selection according to priority is performed. If the MBMS service for the FLC application is selected in the service selection, the terminal stops the service currently being received and performs reselection to the PL according to the result of the measurement for the PL. If the service currently being selected is selected in the service selection, the terminal keeps the current cell and continues to receive the received service and does not reselect to the PL.

In this case, when the idle mode terminal receives the FLC Notification message, the idle mode terminal reselects and moves to the PL if the result of the measurement for the PL is sufficient.

In step 441, the session of the service is started, and in steps 431 to 441, a counting procedure for counting the number of terminals receiving the service, a channel type determination, and a radio bearer determination are performed.

Thereafter, when the session is started in step 441, the RNC periodically transmits the FLC Notification message for the session of the service in steps 451 to 452. This is to support the mobility of the terminal. The NPL terminal moving to another third cell receives the FLC Notification message, such as steps 451 to 452, which are periodically transmitted. If FLC is required, the NPL terminal transmits the FLC Notification message based on the service ID of the FLC Notification message and the PL information. In this way, the cell can be reselected to the PL to receive the service continuously.                     

 In FIG. 6, the application of a method of notifying whether the connected mode terminal is applied with the FLC is applied as an example among the FLC application methods proposed by the present invention. However, as long as the FLC application method is applied to a specific RRC state. When using the flag's flag value or determining whether to apply a separate FLC according to each state of the connected mode in the network, it may be given as a 4-bit bitmap format or a 2-bit integer representation value.

As described above, the connected mode terminal can perform the FLC efficiently by knowing the resource availability information of the corresponding cell through the FLC_DI.

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 those equivalent to the scope of the claims.

In the present invention operating as described in detail above, the effects obtained by the target among the disclosed inventions will be briefly described as follows.

The present invention has an effect of preventing a state in which traffic for a specific service cannot be accepted at a target frequency by being provided with a radio resource state for a service that a connected mode terminal wants to receive.

Claims (11)

In a mobile communication system for a multimedia broadcasting / multicast (MBMS) service, a method for moving terminals to a frequency band where a corresponding service is provided, Measuring a radio resource of a preferred frequency for the service to determine movement of a terminal located at a non-preferred frequency to a preferred frequency; Determining whether to apply FLC (Frequency Layer Convergence) of terminals located at the non-preferred frequency as the radio resource of the measured preferred frequency; And transmitting the determined FLC information on whether to apply the information to the terminals. The method of claim 1, wherein the determining of whether to apply the FLC comprises: When the radio resource state of the preferred frequency is sufficient and the traffic of the terminals corresponding to each state of the connected mode and the terminals that want to receive the service of the preferred frequency at the non-preferred frequency is sufficiently acceptable, the FLC condition is satisfied. Determine to apply FLC to the terminals. In a mobile communication system for a multimedia broadcasting / multicast (MBMS) service, a method for a terminal to move to a frequency band where a corresponding service is provided, Receiving a FLC notification message related to whether FLC (Frequency Layer Convergence) is applied from a radio network controller (RNC); Checking whether the terminal receives the FLC and whether the terminal is located at a non-preferred frequency; And if the terminal applies the FLC and is located in a cell of a non-preferred frequency, performing a cell reselection to a cell of the preferred frequency. The method of claim 3, wherein And if the terminal applies the FLC, the terminal maintains the current cell. The method of claim 4, wherein determining whether to apply the FLC comprises: If the radio resource state of the preferred frequency is sufficient and traffic of the terminals corresponding to the respective states of the connected mode and the terminal to receive the service of the preferred frequency at the non-preferred frequency is sufficiently acceptable, the FLC condition is satisfied. Determine to apply FLC to the terminals. The method of claim 5, wherein the FLC application information, The application of FLC to a terminal or a specific RRC state can be represented by a flag value of one bit, and to determine whether to apply FLC separately according to each state of the connected mode in the network, 4-bit bitmap format or 2-bit It can also be given as an integer expression value of. In a mobile communication system for a multimedia broadcasting / multicast (MBMS) service, a method for a terminal to move to a frequency band where a corresponding service is provided, Receiving a FLC notification message related to FLC (Frequency Layer Convergence) availability information from a Radio Network Controller (RNC), Checking whether the terminal receives the FLC and whether the terminal is located in a cell of a non-preferred frequency; And if the terminal is located in a cell of a non-preferred frequency without applying the FLC, maintaining the current cell or performing a service selection process. The method of claim 7, wherein performing the service selection comprises: Selecting one of a service notified by the FLC notification message and an existing receiving service. The method of claim 8, wherein performing the service selection comprises: Selecting a high priority service through interaction with a user or the wireless controller. The method of claim 7, wherein whether to apply the FLC, When the radio resource state of the preferred frequency is sufficient and the traffic of the terminals corresponding to each state of the connected mode and the terminals that want to receive the service of the preferred frequency at the non-preferred frequency is sufficiently acceptable, the FLC condition is satisfied. Determine to apply FLC to the terminals. The method of claim 10, wherein the FLC application information, The application of FLC to a terminal or a specific RRC state can be represented by a flag value of one bit, and to determine whether to apply FLC separately according to each state of the connected mode in the network, 4-bit bitmap format or 2-bit It can also be given as an integer expression value of.

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