JP5061827B2 - Wireless network control device, resource management method and program - Google Patents

Description

  The present invention relates to a radio network controller, a resource management method, and a program for managing radio resources in a mobile communication system that provides MBMS (Multimedia Broadcast Multicast Service).

  In a general mobile communication system, in order to perform communication between a radio base station and a mobile terminal that is a mobile body, it is necessary to secure radio resources for that purpose. When securing the radio resources necessary for communication, if there is a surplus in the total radio resources of the radio base station, it is necessary to perform the communication from among the available resources. Reserve radio resources. However, when there is no room in the overall radio resources of the radio base station, it is not possible to secure radio resources necessary for performing the communication. Therefore, in order to create a free resource, a channel having a low priority is released from the currently used radio resources. As a result, radio resources necessary for performing the communication are secured from among the free resources created.

  Here, as information for determining the priority order, the Priority Level and RNC of each channel that is notified when a service is requested from the CN (Core Network) to the RNC (Radio Network Controller) that is the radio network controller is wireless. It is common to use information on the spreading factor of the downlink physical channel and the uplink Min UL Channelization Code Length set in the Node B that is the base station.

  As described above, when an existing channel is released due to resource shortage or congestion, as long as it is an environment using an individual channel, it is affected that data communication is interrupted by releasing a certain channel. Only one mobile terminal is using the released channel.

  On the other hand, in recent years, MBMS (Multimedia Broadcast Multicast Service) using a PtM (Point to Multipoint) method has been introduced. This MBMS is a service proposed in 3GPP Release6, and one network resource (including radio resources) is shared by multiple mobile terminals, and multimedia data is simultaneously transmitted from the RNC to multiple mobile terminals. Technology. By using this MBMS in the PtM method, it becomes possible to efficiently use network resources. As a result, carriers providing mobile phone services can increase their profits with a small capital investment. MBMS is realized using the S-CCPCH channel, which is a common channel.

  FIG. 11 is a diagram illustrating an example of a general mobile communication system.

  The mobile communication system shown in FIG. 11 includes CN 1100, RNC 1101, and NodeB 1201. In addition, a UE group 1301, UEs 1302 and 1303, and an idle UE group 1304 exist in a cell 1202, which is a cover area where the NodeB 1201 provides a service.

  The CN 1100 is an upper network of the RNC 1101 connected to the RNC 1101 through a wired line such as an optical cable. The RNC 1101 is a general radio network controller (Radio Network Controller). Node B 1201 is a general radio base station, and performs radio communication with UE group 1301, UE 1302, and 1303. Here, UE group 1301 is a mobile terminal group that receives S-CCPCH (Secondary Common Control Physical Channel) in order to receive MBMS from NodeB 1201. UEs 1302 and 1303 are mobile terminals that receive a dedicated physical channel (DPCH) in order to receive individual services (voice and packet communication). The UE group 1301, UE 1302, and 1303 are in a state of performing communication and are in a connected mode. On the other hand, the Idle UE group 1304 is a group of mobile terminals in Idle mode that are not communicating.

  The MBMS Counting procedure is described below. MBMS Counting is a procedure for investigating how many users want to receive a service to be started when MBMS is started. That is, the audience rating of multimedia data is investigated. This is, for example, one of the information in the technology described in Patent Document 1 in which the RNC obtains information related to mobile terminals under the RNC.

  FIG. 12 is a diagram showing the procedure of MBMS Counting.

  As shown in FIG. 12, signal transmission / reception is performed between UTRAN 1400 which is a radio access network including RNC 1101 and NodeB 1201 shown in FIG. 11 and UE 1401 which is a mobile terminal.

  First, MBMS ACCESS INFORMATION is transmitted from UTRAN 1400 to UE 1401. This MBMS ACCESS INFORMATION is a signal that the UTRAN 1400 informs the UE 1401 that MBMS is started.

  After that, if the UE 1401 that has received the MBMS ACCESS INFORMATION is an idle mode UE, the UE 1401 wishes to receive the service notified by the MBMS ACCESS INFORMATION, and meets the response conditions of the MBMS Counting, the UE 1401 requests a connection. A signal RRC connection request is transmitted to the UTRAN 1400. In addition, when UE 1401 that has received MBMS ACCESS INFORMATION is a connected mode UE, and UE 1401 desires to receive the service notified by MBMS ACCESS INFORMATION and meets the response conditions of MBMS Counting, cell update from UE 1401 A cell update signal is transmitted to the UTRAN 1400.

  The UTRAN 1400 can measure the audience rating of the MBMS based on the response signal transmitted from the UE 1401.

Note that the UE response conditions to the MBMS ACCESS INFORMATION described above are the contents defined in 3GPP Release 6 TS25.331, and thus detailed description thereof will be omitted.
JP 2005-65260 A

  However, if resource control is performed based on information such as Priority Level, spreading factor, Min UL Channelisation Code Length, etc. that are generally used for S-CCPCH used in MBMS, the S-CCPCH is released. This may affect many users who are receiving MBMS. For example, when MBMS is provided in S-CCPCH with a large spreading factor (ie, low radio resource usage) and low priority level, the resource is released as a result of resource control due to lack of radio resources. There is a problem in that all mobile terminals that have received the MBMS cannot receive the MBMS. Because it provides MBMS in PtM format instead of PtP (Point to Point) format, there is a result that many mobile terminals want to receive the MBMS in the cell which is the coverage area. This is because the resource setting of the method is performed.

  In addition, a control method may be considered in which the S-CCPCH used in the PtM method is not subject to resource control. In order to transmit MBMS data to all mobile terminals existing in a cell using a common channel, MBMS is transmitted with transmission power larger than that of other dedicated channels. In other words, the S-CCPCH is likely to have a great influence on the radio environment. For this reason, when resource control becomes necessary due to the occurrence of a congestion state, the S-CCPCH providing MBMS should be the control target.

  The present invention has been made in view of the problems of the conventional techniques as described above, and is a radio network control apparatus and resource management capable of appropriately controlling resources of a common channel used in MBMS. An object is to provide a method and a program.

In order to achieve the above object, the present invention provides:
A wireless network control device for simultaneously transmitting multimedia data to a plurality of mobile terminals using a common channel,
An audience rating calculator for calculating the audience rating of the multimedia data for each channel;
And a resource management unit that releases a channel whose audience rating is smaller than a predetermined threshold when releasing the channel according to a predetermined priority.

  As described above, in the present invention, when the viewing rate of multimedia data simultaneously transmitted to a plurality of mobile terminals using a common channel is calculated for each channel, and the channel is released according to a predetermined priority, the viewing rate Is configured to release a channel smaller than a predetermined threshold, so that the resources of the common channel used in MBMS can be appropriately controlled.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing an embodiment of a wireless network control device of the present invention.

  As shown in FIG. 1, this embodiment includes a CN 100, an RNC 101, and a NodeB 201. In addition, a UE group 301, UEs 302 and 303, and an Idle UE group 304 exist in a cell 202 that is a cover area where the NodeB 201 provides a service.

  The CN 100 is an upper network of the RNC 101 connected to the RNC 101 via a wired line such as an optical cable.

  The RNC 101 is a radio network controller (Radio Network Controller), and performs communication between the CN 100 and the NodeB 201. NodeB 201 is controlled mainly based on signals transmitted from CN 100. Moreover, the radio | wireless resource in the radio area between UE (User Equipment) which is a mobile terminal under NodeB201 and NodeB201 is managed and controlled.

  The NodeB 201 is a general radio base station, and performs radio communication with the UE group 301 and the UEs 302 and 303. Here, the UE group 301 is a mobile terminal group that receives an S-CCPCH (Secondary Common Control Physical Channel) in order to receive an MBMS (Multimedia Broadcast Multicast Service) from the NodeB 201. UEs 302 and 303 are mobile terminals that receive DPCH (Dedicated Physical Channel) in order to receive individual services (voice and packet communication). The UE group 301 and the UEs 302 and 303 are in a communication state and are in a connected mode. In contrast, the Idle UE group 304 is a group of mobile terminals in Idle mode that are not communicating.

  FIG. 2 is a diagram illustrating a configuration example of the RNC 101 illustrated in FIG.

  As shown in FIG. 2, the RNC 101 shown in FIG. 1 includes a channel control unit 110, an MBMS setting unit 111, an audience rating calculation unit 112, a resource management unit 113, and a resource management table 114. .

  The channel control unit 110 controls and sets a channel used for communication with a subordinate mobile terminal based on a signal transmitted from the CN 100. Further, the resource controlled by the resource management unit 113 is assigned to the channel.

  The MBMS setting unit 111 sets a mobile terminal that provides MBMS based on the channel information set by the channel control unit 110. Also, when providing MBMS, MBMS ACCESS INFORMATION is transmitted to the mobile terminal via NodeB 201.

  The audience rating calculation unit 112 calculates the audience rating based on the RRC connection request or Cell Update transmitted from the mobile terminal with respect to the MBMS ACCESS INFORMATION transmitted from the MBMS setting unit 111. That is, the audience rating is calculated from the information obtained as a result of MBMS counting.

  The resource management unit 113 controls resources in the radio section based on the result of channel control / setting by the channel control unit 110 and the resource management information stored in the resource management table 114. Further, the resource management information stored in the resource management table 114 is rearranged based on the information of each channel and the audience rating calculated by the audience rating calculation unit 112. Then, the resource management information stored in the resource management table 114 is managed.

  The resource management table 114 stores radio section resource management information.

  FIG. 2 shows only the components related to the present invention.

  FIG. 3 is a diagram showing an example of the structure of the resource management table 114 shown in FIG.

  As shown in FIG. 3, the resource management table 114 shown in FIG. 2 stores resource management information including the priority level, spreading factor, Min UL Channelisation Code Length, and audience rating information of each channel. Thereby, the radio | wireless resource of each channel can be read. The use of audience rating information for resource control and management is one of the features of the present invention.

  Each Priority Level is a Priority Level obtained as a result of processing inside the RNC 101 what is notified from the CN 100. An integer of 0 to 15 can be set, 0 is Spare, 15 is No priority, 1 is the highest, and 14 is the lowest priority (see 3GPP Release 6 TS25.413). Since the setting method of Priority Level uses a general method, details are not mentioned here.

  The spreading factor is a spreading factor of a physical channel used for downlink communication. The smaller this value, the more radio resources are used.

  The Min UL Channelization Code Length represents the length of the Channelization Code used for spreading the physical channel used for uplink communication. The smaller this value, the more radio resources are used.

  The audience rating information is information obtained as a result of MBMS counting, and is information added only to S-CCPCH used for MBMS data transfer of PtM (Point to Multipoint).

  In the resource management table 114, common channels essential for cell operation are not included because they cannot be released during resource control. In addition, since the audience rating cannot be defined in the individual channel, it is undefined “-”. Also, since S-CCPCH is a downlink-only channel, the Min UL Channelization Code Length defined by Uplink is undefined “-”. Based on these pieces of information, the resource management unit 113 performs an operation (release or change of existing resources) when resource control becomes necessary due to resource shortage or congestion.

  The resource management unit 113 also has a threshold value Thr_AR used for resource control.

  FIG. 4 is a diagram illustrating an example of the threshold value Thr_AR held by the resource management unit 113 illustrated in FIG.

  A threshold value Thr_AR as shown in FIG. 4 is held in the resource management unit 113, and this threshold value Thr_AR is an arbitrary value set by the operator. The threshold Thr_AR is used for resource control.

  FIG. 5 is a diagram illustrating channel mapping in the PtM method and the PtP (Point to Point) method.

  In the PtM system, as shown in the upper part of FIG. 5, the channel used for user data transfer is logical channel MTCH 431 (MBMS point-to-multipoint traffic channel) to transport channel FACH 432 (Forward Access Channel). To be mapped. Further, the channel configuration is such that the FACH 432 is mapped to the physical channel S-CCPCH 433. S-CCPCH is a common channel and can transmit the same data to a plurality of users at the same time.

  Further, in the PtP method, as shown in the lower part of FIG. 5, the channel used for user data transfer is the DTCH 435 (Dedicated Traffic Channel) of the logical channel and the DCH 436 of the transport channel, similar to the existing dedicated channel user. Maps to (Dedicated Channel). Further, the channel configuration is such that the DCH 436 is mapped to the physical channel DPCH 437 (Dedicated Physical Channel).

  Since the PtM scheme uses S-CCPCH, which is a common channel, it is possible to simultaneously transfer the same information to a plurality of users using one channel. On the other hand, in the PtP method, it is necessary to set a DPCH that is a dedicated channel for each user, and thus it is understood that a lot of radio resources are required. On the other hand, when DPCH is used, since power control can be performed for each user, the transmission power of the entire cell can be kept low. For this reason, the determination of which transfer method, the PtM method or the PtP method, should be used depends on the control method inside the RNC and the operator setting method (reference: 3GPP Release 6).

  The resource management method in the RNC 101 shown in FIG. 1 will be described below.

  FIG. 6 is a flowchart for explaining a resource management method in the RNC 101 shown in FIG. Here, a resource management method when a congestion state is detected in a downlink radio section during normal operation will be described. In addition, the congestion state is a state in which at least one of Uplink and Downlink in the wireless section has excessive transmission power, and wireless communication within the cell may not be performed normally due to interference, or may not be performed normally. It is.

  When a congestion state occurs in the wireless network, UTRAN controls wireless resources. Until this congestion state is resolved, it is necessary to perform control to change the setting so that radio resources with a mobile terminal that is less affected by the release are released or the radio resource usage is reduced. The mobile terminals that are less affected by the release are determined based on the priority order of each channel stored in the resource management table 114. In this embodiment, for simplification, it is assumed that only existing resources are released when congestion occurs.

  First, when it is detected in UTRAN that a congestion state has occurred (step S1), it is determined whether MBMS is currently provided in the PtM format (step S2). Specifically, the processing in step S1 is performed by the channel control unit 110 and the resource management unit 113. Further, the processing in step S2 is performed by the MBMS setting unit 111.

  If it is determined in step S2 that MBMS is currently provided in the PtM format, the audience rating calculation unit 112 calculates the audience rating (step S3). This is done by using MBMS Counting as described above.

  Thereafter, resource control is performed by the resource management unit 113 based on the resource management information stored in the resource management table 114 and the calculated audience rating information (step S4).

  As a result of the resource control in step S4, the channel control unit 110 and the resource management unit 113 determine whether or not the congestion state is released (step S5).

  If it is determined in step S5 that the congestion state has not been released, the process of step S2 is performed again. Steps S2 to S4 are performed until it is determined in step S5 that the congestion state has been released.

  On the other hand, when it is determined in step S2 that MBMS is not currently provided in the PtM method, normal resource control is performed in the resource management unit 113 (step S6). Normal resource control is general resource control for only individual channels.

  As a result of the resource control in step S6, the channel control unit 110 and the resource management unit 113 determine whether or not the congestion state has been released (step S7).

  The process of step S6 is performed until it is determined in step S7 that the congestion state has been released.

  FIG. 7 is a flowchart for explaining the details of the normal resource control processing in step S6 shown in FIG.

  First, the resource management unit 113 rearranges the resource management information stored in the resource management table 114 in order from the lowest priority level (step S10).

  Subsequently, the resource management unit 113 rearranges the resource management information stored in the resource management table 114 in ascending order of the spreading rate (step S11).

  Further, the resource management unit 113 rearranges the resource management information stored in the resource management table 114 in order from the smallest Min UL Channelization Code Length (step S12).

  Thereafter, the channel of List No = 1 in the resource management table 114, that is, the channel existing at the top of the resource management table 114 is released by the resource management unit 113 (step S13).

  Then, the resource management table 114 is updated by the resource management unit 113 (step S14). Here, the channel of List No = 1 is deleted.

  In the resource management table 114 shown in FIG. 3, the S-CCPCH used in the PtM method is present, so the normal resource control process in step S6 is not performed. In this process, audience rating information in the resource management table 114 is not used.

  FIG. 8 is a flowchart for explaining details of the resource control processing in consideration of the audience rating in step S4 shown in FIG.

  First, the resource management unit 113 rearranges the resource management information stored in the resource management table 114 in order from the lowest priority level (step S20).

  Subsequently, the resource management unit 113 rearranges the resource management information stored in the resource management table 114 in descending order of the spreading rate (step S21).

  Further, the resource management unit 113 rearranges the resource management information stored in the resource management table 114 in order from the smallest Min UL Channelization Code Length (step S22).

  FIG. 9 shows the resource management information stored in the resource management table 114 rearranged by the resource management unit 113 in steps S20 to S22.

  As shown in FIG. 9, in the resource management table 114, the resource management information of the used channels is displayed in order from the lowest priority level, further from the lowest spreading factor, and further from the Min UL Channelisation. They are arranged in order from the smallest Code Length.

  Thereafter, the maximum value of List No is substituted into the variable User Number (step S23). User Number represents the number of channels stored in the resource management table 114. As a result, all the channels stored in the resource management table 114 are referred to in the following processing.

  Subsequently, the variable i is set to the initial value “0” (step S24), and “1” is added to the variable i (step S25).

  Then, the audience rating of the i-th channel whose List No in the resource management table 114 is compared with Thr_AR, and it is determined whether the audience rating is equal to or higher than Thr_AR (step S26). Alternatively, it is determined whether the audience rating is undefined.

  If it is determined in step S26 that the audience rating is equal to or greater than Thr_AR, or if it is determined that the audience rating is undefined, it is determined whether the current value of variable i is equal to User Number. (Step S27).

  If it is determined in step S27 that the current value of variable i is not equal to User Number, the process of step S25 is performed again.

  On the other hand, if it is determined in step S26 that the audience rating is not equal to or greater than Thr_AR, the channel whose List No is i-th is released (step S28). Then, the resource management table 114 is updated (step S29). Thereafter, the process ends.

  If it is determined in step S27 that the current value of variable i is equal to User Number, the process ends.

  As described above, by including the branch of step S26 in the resource control, it is possible to prevent the channel from being released when the audience rating is larger than a predetermined value (Thr_AR). .

  Note that the processing of the above steps S23 to S29 is performed by the resource management unit 113.

  Hereinafter, other embodiments of the present invention will be described.

  In the above-described embodiment, Thr_AR is a static value determined in advance. However, this value may be dynamically changed to perform more optimal operation. The larger the Thr_AR value, the easier the S-CCPCH used in MBMS is released. Also, the smaller the Thr_AR value, the harder the S-CCPCH used in MBMS is released.

  FIG. 10 is a diagram illustrating a state when Thr_AR is dynamically changed according to the User Number.

  As shown in FIG. 10, Thr_N1 and Thr_N2 are defined in User Number. These are thresholds for the number of users (User Number) existing in the cell, and Thr_AR is changed as follows according to the User Number.

When 0 ≦ User Number <Thr_N1, Thr_AR = Thr_AR1
When Thr_N1 ≦ User Number <Thr_N2, Thr_AR = Thr_AR2
When Thr_N2 ≦ User Number, Thr_AR = Thr_AR3
Note that the above-described processing may be performed by a logic circuit manufactured according to the purpose. Alternatively, a program describing processing contents may be recorded on a recording medium readable by the RNC 101, and the program recorded on the recording medium may be read by the RNC 101 and executed. The recording medium readable by the RNC 101 refers to a HDD or the like built in the RNC 101 in addition to a transferable recording medium such as a floppy disk (registered trademark), a magneto-optical disk, a DVD, or a CD. The program recorded on this recording medium is read by a CPU (not shown) in the RNC 101, and the same processing as described above is performed under the control of the CPU. Here, the CPU operates as a computer that executes a program read from a recording medium on which the program is recorded.

  As described above, in the present invention, resource control using the audience rating is performed, so it is possible to avoid releasing MBMS with a high audience rating during resource control.

It is a figure which shows one Embodiment of the radio network control apparatus of this invention. It is a figure which shows the example of 1 structure of RNC shown in FIG. FIG. 3 is a diagram illustrating an example of a structure of a resource management table illustrated in FIG. 2. It is a figure which shows an example of threshold value Thr_AR which the resource management part shown in FIG. 2 holds. It is a figure which shows the mapping of the channel in a PtM system and a PtP (Point to Point) system. 3 is a flowchart for explaining a resource management method in the RNC shown in FIG. 1. FIG. 7 is a flowchart for explaining details of normal resource control processing in step S6 shown in FIG. 6; FIG. 7 is a flowchart for explaining details of a resource control process in consideration of the audience rating in step S4 shown in FIG. 6. This is resource management information stored in the resource management table rearranged by the resource management unit in steps S20 to S22. It is a figure which shows a mode when Thr_AR is changed dynamically according to User Number. It is a figure which shows an example of a general mobile communication system. It is a figure which shows the procedure of MBMS Counting.

Explanation of symbols

100 CN
101 RNC
110 Channel Control Unit 111 MBMS Setting Unit 112 Audience Rating Calculation Unit 113 Resource Management Unit 114 Resource Management Table 201 NodeB
202 cell 301 UE group 302, 303 UE
304 Idle UE group 431 MTCH
432 FACH
433 S-CCPCH
435 DTCH
436 DCH
437 DPCH

Claims (9)

A wireless network control device for simultaneously transmitting multimedia data to a plurality of mobile terminals using a common channel,
An audience rating calculator for calculating the audience rating of the multimedia data for each channel;
A resource management unit that releases channels having a viewing rate smaller than a predetermined threshold in order from a channel having a smaller spreading rate when releasing the channels according to a priority order based on a notification from an upper network; Wireless network control device. The radio network controller according to claim 1, wherein
A resource management table for storing resource management information indicating radio resources of the channel;
The radio network controller according to claim 1, wherein the resource manager rearranges the resource management information stored in the resource management table according to the priority order and the spreading factor . The radio network controller according to claim 1, wherein
The radio network controller according to claim 1, wherein the resource manager changes the threshold based on a number of mobile terminals that receive the multimedia data. A resource management method in a radio network controller for simultaneously transmitting multimedia data to a plurality of mobile terminals using a common channel,
Processing for calculating the audience rating of the multimedia data for each channel;
In the case of releasing the channel according to the priority order based on the notification from the upper network, the resource management includes: releasing the channels having the audience rating smaller than a predetermined threshold in order from the channel having the lowest spreading rate. Method. The resource management method according to claim 4,
A resource management method comprising : rearranging resource management information indicating radio resources of the channel stored in a resource management table provided in the radio network control device according to the priority and the spreading factor . The resource management method according to claim 4,
A resource management method comprising a process of changing the threshold based on the number of mobile terminals that receive the multimedia data. A radio network controller that simultaneously transmits multimedia data to a plurality of mobile terminals using a common channel.
Calculating the audience rating of the multimedia data for each channel;
When releasing the channel according to the priority order based on the notification from the higher-level network, a program for executing a procedure for releasing the channels whose audience rating is smaller than a predetermined threshold in order from the channel having the lowest spreading rate. . The program according to claim 7,
A program for further executing a procedure of rearranging resource management information indicating radio resources of the channel stored in a resource management table provided in the radio network control device according to the priority and the spreading factor . The program according to claim 7,
A program for further executing a procedure for changing the threshold based on the number of mobile terminals that receive the multimedia data.

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