Patent Publication Number: US-2016249353-A1

Title: System and method for network control

Description:
TECHNICAL FIELD 
     This application relates to control of a mobile communication network. 
     BACKGROUND ART 
     Examples of a mobile communication network include a Universal Mobile Telecommunications System (UMTS) and an Evolved Packet System (EPS). Each mobile communication network includes a radio access network (RAN) and a core network (CN). Examples of a RAN include a UMTS Terrestrial Radio Access Network (UTRAN) and an Evolved UTRAN (EUTRAN). Examples of a Core Network include a UMTS Core Network and an Evolved Packet Core (EPC). Each RAN includes a base station (e.g., NodeB and Evolved NodeB) that is connected to a mobile station by means of a radio access technology. Each core network is accessed from a mobile station through a RAN and provides the mobile station with a connection service (e.g., Internet Protocol (IP) connection service) for connecting to an external network. 
     Further, in this specification, a mobile communication network includes a mobile backhaul (MBH). Each mobile backhaul is a network that connects between a site (cell site) where a base station (e.g., NodeB and Evolved NodeB) is placed and a site where a higher network node (e.g., Radio Network Controller (RNC), SGSN Serving GPRS Support Node (SGSN), Serving Gateway (SGW), Mobility Management Entity (MME)) is placed. Each mobile backhaul includes a physical layer (layer 1) network and a packet transport network for transferring IP packets on the physical layer network, and provides an IP packet transfer service between a base station and a higher network node. The physical layer network is composed of optical fibers (e.g., Passive Optical Network (PON), Synchronous Optical Network (SONET)/Synchronous Digital Hierarchy (SDH), Wavelength Division Multiplexing (WDM)), copper wires (e.g., E1/T1 network, Digital Subscriber Line (DSL)), radio links (e.g., microwave point-to-point link), or any combination thereof. Each packet transport network uses, for example, Virtual Local Area Network (VLAN) technologies, Multi-Protocol Label Switching (MPLS) technologies, or a combination thereof. 
     Network sharing is used to share the costs required to build a mobile communication network among a plurality of Mobile Network Operators (MNO). There are various ways for the network sharing. For example, Non Patent Literature 1 discloses two configurations for sharing a RAN among a plurality of MNOs, which are a Gateway Core Network (GWCN) and a Multi-Operator Core Network (MOCN). In the GWCN, a RAN is shared by a plurality of MNOs, and one or more CN nodes (e.g., SGSN or MME) are also shared by the plurality of MNOs. On the other hand, in the MOCN, a RAN is shared by a plurality of MNOs, but a core network is not shared. Specifically, in the MOCN, CN nodes (e.g., SGSN or MME) of each MNO are connected to the same RAN node (e.g., RNC or eNodeB). 
     Further, a virtualized core network is known as architecture for allowing a plurality of MNOs to share one core network (e.g., see Patent Literatures 1 and 2). The virtualized core network uses server virtualization technologies and network virtualization technologies, and abstracts a core network control plane, or date plane, or both. Specifically, in the virtualized core network, CN nodes (e.g., MME, S/PGW control plane, and S/PGW data plane) of each MNO are implemented as virtual machines that is configured in a server pool or a virtual router that is configured in physical switches. 
     When a plurality of MNOs shares a RAN or shares both a RAN and a core network, a mobile backhaul is also shared by the plurality of MNOs. Accordingly, the mobile backhaul transfers the traffic of the plurality of MNOs. 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: United States Patent Publication No. 2012/0300615 
         Patent Literature 2: United States Patent Publication No. 2013/0183991 
       
    
     Non Patent Literature 
     
         
         Non-Patent Literature 1: 3GPP TS 23.251 V11.5.0 (March 2013), “3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Network Sharing; Architecture and functional description (Release 11)”, March 2013 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     When a plurality of MNOs shares a RAN, a mobile backhaul, and a core network, network resource allocation needs to be configured on each of the RAN, the mobile backhaul, and the core network in accordance with an agreement or a contract that defines the slicing of network resources among the plurality of MNOs. However, network resources to be allocated to the plurality of MNOs are different among the RAN, the mobile backhaul, and the core network. To be specific, the network resources of the RAN are radio resources that include at least one of a time and frequencies and transmission power. The network resources of the RAN may include, in place of or in combination with radio resources, at least one of: the number of user equipments (UEs) that have established wireless connections; cell load that is calculated on the basis of a UE type and an established bearer type; transport resources; and hardware resources in the RAN such as Central Processing Units (CPUs) and memories. The network resources of the mobile backhaul, for example, include a guaranteed bandwidth for a VLAN or a MPLS label path obtained by traffic shaping and traffic scheduling, and also include queue priority and weight configurations for a Weighted Round Robin (WRR) or Weighted Fair Queuing (WFQ) on the basis of a traffic type (e.g., VLAN ID, UE type, established bearer type, DiffSery Code Point (DSCP)). Further, the network resources of the core network, for example, include a CPU utilization rate, a memory utilization rate, guaranteed bandwidths for inbound traffic and outband traffic in a data-plane CN node (e.g., SGW, PGW, SGSN data plane, Gateway GPRS Support Node (GGSN)), and also include processing times of a control-plane CN node. Further, in the case of the virtualized core network, the network resources of the core network include computing resources or bandwidths (switching capacity) allocated to a virtualized CN node. Therefore, an operator needs to perform setting on each of the RAN, the mobile backhaul and the core network in accordance with an agreement or contract that defines the slicing of network resources among the plurality of MNOs, which raises a problem that a burden of the configuration operation is large. 
     An object of at least one of embodiments disclosed in this specification is to address the above problem. Specifically, one of objects to be achieved by embodiments disclosed in this specification is to provide a system, an apparatus, a method, and a program for network control that can contribute, when at least two of a RAN, a mobile backhaul, and a core network are shared among a plurality of MNOs, to improving the efficiency of performing setting of network resource allocation on the at least two networks to be shared. 
     Solution to Problem 
     In an embodiment, a network control system includes a control module. The control module is configured to enforce a network resource configuration to each of at least two of a RAN, a mobile backhaul, and a core network in accordance with common resource partitioning information indicating slicing of network resources among a plurality of MNOs, in order to allow the plurality of mobile network operators to share the at least two networks. 
     In an embodiment, a control method includes (a) receiving common resource partitioning information indicating slicing of network resources among a plurality of MNOs, and (b) converting the resource partitioning information into configuration information of network resources to be applied to each of at least two of a RAN, a mobile backhaul, and a core network, in order to allow the plurality of MNOs to share the at least two networks. 
     In an embodiment, a program includes instructions (software codes) for causing a computer to perform the above-described control method when the program is loaded into the computer. 
     In an embodiment, a network control apparatus includes a mediation module. The mediation module is configured to convert common resource partitioning information, indicating slicing of network resources among a plurality of MNOs, into configuration information of network resources to be applied to each of at least two of a RAN, a mobile backhaul, and a core network, in order to allow the plurality of MNOs to share the at least two networks. 
     Advantageous Effects of Invention 
     According to the above-described embodiments, it is possible to provide a system, an apparatus, a method, and a program for network control that can contribute, when at least two of a RAN, a mobile backhaul, and a core network are shared among a plurality of MNOs, to improving the efficiency of performing setting of network resource allocation on the at least two networks to be shared. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram showing one example of network sharing (i.e., MOCN); 
         FIG. 2  is a diagram showing one example of network sharing (i.e., GWCN); 
         FIG. 3  is a diagram showing one example of network sharing (i.e., virtualized core network); 
         FIG. 4  is a diagram showing a configuration example of a network control system according to first to third embodiments; 
         FIG. 5  is a flowchart showing one example of network control based on resource partitioning information indicating the slicing of network resources among a plurality of MNOs according to the first embodiment; 
         FIG. 6  is a flowchart showing one example of network control based on resource partitioning information indicating the slicing of network resources among a plurality of MNOs according to the second embodiment; and 
         FIG. 7  is a flowchart showing one example of network control according to the third embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Specific embodiments will hereinafter be described in detail with reference to the drawings. The same or corresponding elements are denoted by the same reference symbols throughout the drawings and repeated descriptions thereof are omitted as appropriate to clarify the explanation. 
     Embodiments below are described mainly with respect to an Evolved Packet System (EPS). However, those embodiments is not limited to EPS and may be applied to other mobile communication networks or systems, such as an UMTS and a global system for mobile communications (GSM)/General packet radio service (GPRS) system. 
     First Embodiment 
     First, several examples of network sharing to which a plurality of embodiments including this embodiment is directed are described.  FIG. 1  shows an example of the MOCN. Specifically, in the example shown in  FIG. 1 , an EUTRAN  10  and a mobile backhaul  20  are shared by two MNOs (i.e., MNO A and MNO B). On the other hand, core networks (EPC  30 A and EPC  30 B) of MNO A and MNO B are not shared. 
     The EUTRAN  10  includes an eNB  11 . The eNB  11  communicates with UEs  12 . The UEs  12  include a UE(s) that has subscribed to the MNO A and a UE(s) that has subscribed to the MNO B. The UE(s) that has subscribed to the MNO A receives a service  40 A from the MNO A through the common EUTRAN  10 , the common mobile backhaul  20 , and the EPC  30 A of the MNO A. On the other hand, the UE(s) that has subscribed to the MNO B receives a service  40 B from the MNO B through the common EUTRAN  10 , the common mobile backhaul  20 , and the EPC  30 B of the MNO B. 
     The mobile backhaul  20  connects the eNB  11  to the EPC  30 A of the MNO A and the EPC  30 B of the MNO B. In the example shown in  FIG. 1 , the mobile backhaul  20  includes packet communication devices  21  and  22  and radio transmission devices  23  and  24 . The radio transmission devices  23  and  24  are configured to establish a point-to-point radio link  25  using, for example, microwaves or millimeter waves, and communicate with each other through the point-to-point radio link  25 . The radio transmission devices  23  and  24  communicate with the packet communication devices  21  and  22  through, for example, a LAN interface. The packet communication devices  21  and  22  relay data packets (e.g., layer-2 protocol data units (PDUs) or layer-3 PDUs) between the eNB  11  and a higher network node (i.e. MMEs and SGWs in the EPC  30 A and the EPC  30 B). Each of the packet communication devices  21  and  22  may be a layer-2 switch or a layer-3 switch. Alternatively, each of the packet communication devices  21  and  22  may be a MPLS label switch router (LSR). Note that, the configuration of the mobile backhaul  20  shown in  FIG. 1  is merely an example. The mobile backhaul  20  may include an optical communication network such as PON, SONERT/SDH or WDM, or may include a copper wire network such as DSL or E1/T1. 
       FIG. 2  shows an example of the GWCN. In the example shown in  FIG. 2 , the EUTRAN  10  and the mobile backhaul  20  are shared by the MNO A and MNO B, just like the case of the MOCN in  FIG. 1 . Further, in the example shown in  FIG. 2 , a part of the core network (common EPC  31  shown in  FIG. 2 ) is also shared by the MNO A and MNO B. The common EPC  31  includes an MME and an SGW. The common EPC  31  is connected to an individual EPC  32 A of the MNO A and an individual EPC  32 B of MNO B. Each of the EPC  32 A and the EPC  32 B includes a PGW. 
       FIG. 3  shows an example of a virtualized core network. In the example shown in  FIG. 3 , a virtualized core network  33  includes hardware elements including a server pool and physical switches (not illustrated), and software elements that control those hardware elements to construct virtual machines and virtual routers. Such software elements are generally called a hypervisor or a Virtual Machine Monitor (VMM)). Each of a virtual EPC  34 A of the MNO A and a virtual EPC  34 B of the MNO B includes logical CN nodes (e.g., virtual MME, virtual SGW, virtual PGW) each configured as a virtual machine or a virtual router. 
     Although  FIGS. 1 to 3  show network sharing between two MNOs, the EUTRAN, the mobile backhaul, and the EPC may be shared among three or more MNOs. Further, there are other examples of network sharing different from those shown in  FIGS. 1 to 3 . For example, network virtualization technologies that are applied to the core network in the example shown in  FIG. 3  may also be applied to the common EUTRAN  10  and the common mobile backhaul  20 . A network control system and a network control method according to this embodiment described below may be applied to various network sharing configurations including those shown in  FIGS. 1 to 3 . 
       FIG. 4  shows a configuration example of a network control system  500  according to this embodiment. The network control system  500  receives resource partitioning information indicating the allocation of network resources among a plurality of MNOs. The resource partitioning information is supplied from an Operations Support System (OSS)  600  to the network control system  500 . The resource partitioning information indicates common resource partitioning for the whole of the mobile communication network including the EUTRAN  100 , the mobile backhaul  200 , and the EPC  300 . Stated differently, the resource partitioning indicated by the resource partitioning information is applied in common to the common EUTRAN  100 , the common mobile backhaul  200 , and the common EPC. The resource partitioning information indicates, for example, an amount or a proportion of network resources to be partitioned to each of the plurality of MNOs. There are various specific ways of indicating the network resources to be partitioned in the resource partitioning information. In some implementations, the resource partitioning information may clearly indicate an amount or a proportion of network resources to be partitioned to each of the plurality of MNOs. Alternatively, the resource partitioning information may clearly indicate an amount of network resources to be partitioned to a certain MNO and indicate a proportion of network resources for another MNO to the remaining network resources. 
     In other implementations, the resource partitioning information may indicate an amount or a proportion of resources to be fixedly allocated (guaranteed) to each MNO. In this specification, such a resource partitioning mode is referred to as “full reservation mode”. In the case of the full reservation mode, the resource partitioning information indicates, for example, a proportion of resources fixedly allocated to each MNO, such as “40% to MNO A, 30% to MNO B and 30% to MNO C”. 
     In other implementations, the resource partitioning information may indicate an amount or a proportion of network resources to be fixedly partitioned (guaranteed) to each MNO and an amount or a proportion of network resources to be shared among a plurality of MNOs. In this specification, such a resource partitioning mode is referred to as “partial reservation mode”. In the case of the partial reservation mode, the resource partitioning information indicates, for example, a proportion of resources fixedly allocated to each MNO and a proportion of shared resources, such as “20% to MNO A, 20% to MNO B, 20% to MNO C, and 40% to common resources”. Note that, it is not necessary to clearly indicate the proportion of the shared resources in the resource partitioning information. 
     In yet other implementations, the resource partitioning information may indicate that all network resources are shared among a plurality of MNOs without specifying fixed guaranteed resources (guaranteed bandwidth) to each MNO. In this specification, such a resource partitioning mode is referred to as “full sharing mode”. 
     Referring back to  FIG. 4 , in order to allow a plurality of MNOs to share the common mobile backhaul  200  and the common EPC (or virtual EPC)  300 , the network control system  500  enforces a network resource configuration to each of the EUTRAN  100 , the mobile backhaul  200 , and the EPC  300  in accordance with the resource partitioning information. In the example shown in  FIG. 4 , the network control system  500  includes a Software-Defined Network (SDN) controller  501 , a Self-Organizing Network (SON)/Element Management System (EMS)  502 , a Backhaul Resource Manager (BRM)  503 , and a SON/EMS  504 . The SDN controller  501  functions as a mediation module to convert the resource partitioning information into the resource allocation configurations that are suitable for allocating respective resources of the EUTRAN  100 , the mobile backhaul  200 , and the EPC  300 . The SON/EMS  502 , the BRM  503  and the SON/EMS  504  function as enforcement modules that enforce configurations to a node(s) (e.g., eNB) in the EUTRAN  100 , a node(s) (e.g., packet communication device, radio transmission device) in the mobile backhaul  200 , and a node(s) (e.g., MME, S/PGW) in the EPC  300 , respectively, in accordance with the respective resource allocation configurations generated by the SDN controller  501 . 
     To be more specific, the SDN controller  501  may convert the common resource partitioning information into the resource allocation configuration (RAN configuration information) for the EUTRAN  100 , the resource allocation configuration (backhaul configuration information) for the mobile backhaul  200 , and the resource allocation configuration (EPC configuration information) for the EPC  300 . As described earlier, network resources to be allocated to the plurality of MNOs are different among the EUTRAN  100 , the mobile backhaul  200  and the EPC  300 . Thus, the RAN configuration information, the backhaul configuration information, and the EPC configuration information indicate an configuration of allocating to the MNOs of network resources of the EUTRAN  100 , that of the mobile backhaul  200 , and that of the EPC  300 , respectively. 
     The RAN configuration information indicates, for example, allocation of radio resources (frequencies, time, or resource blocks) of the EUTRAN  100  to the plurality of MNOs. The RAN configuration information is applied by the SON/EMS  502  to an eNB in the EUTRAN  100  and affects scheduling of at least one of downlink transmission and uplink transmission in the eNB. The RAN configuration information may indicate allocation of other network resources of the EUTRAN  100  to the plurality of MNOs. Other network resources of the EUTRAN  100  may include at least one of: the number of connected UEs, cell load calculated on the basis of a UE type and an established bearer type; transport resources; and hardware resources in the RAN such as CPUs and memories. 
     The backhaul configuration information indicates, for example, allocation of a network bandwidth of the mobile backhaul  200  to the plurality of MNOs. For example, the backhaul configuration information is applied by the BRM  503  to a node (e.g., packet communication device, radio transmission device) in the mobile backhaul  200 . The backhaul configuration information affects at least one of: (a) a Virtual Private Network (VPN) configuration; (b) a VLAN configuration; (c) a MPLS configuration; (d) a traffic shaping configuration for a VLAN or a MPLS path; and (d) a traffic scheduling configuration for a VLAN or a MPLS path, in the node in the mobile backhaul  200 . The backhaul configuration information may indicate allocation of other network resources of the mobile backhaul  200  to the plurality of MNOs. Other network resources of the mobile backhaul  200  may include queue priority and weight configurations for a WRR or WFQ on the basis of a traffic type (e.g., VLAN ID, UE type, established bearer type, DiffSery Code Point (DSCP)). 
     In the case of the GWCN architecture shown in  FIG. 2 , the EPC configuration information may indicate allocation of network resources of the EPC (common EPC)  300  to the plurality of MNOs. The EPC configuration information is applied by the SON/EMS  504  to a CN node (e.g., SGW) in the EPC  300  and affects at least one of a traffic shaping configuration and a traffic scheduling configuration in the data plane. The EPC configuration information may indicate allocation of other network resources of the EPC  300  to the plurality of MNOs. Other network resources of the EPC  300  may include a CPU utilization rate, a memory utilization rate, and guaranteed bandwidths for inbound traffic and outband traffic in a CN node. 
     On the other hand, in the case of the virtualized core network architecture shown in  FIG. 3 , the EPC configuration information may indicate allocation of computing resources or switching capacity for causing a hardware element (e.g., server pool, physical switches) in the EPC (virtual EPC)  300  to function as a virtual CN node of each MNO. The EPC configuration information is used, by a hypervisor that directly controls the hardware element (e.g., server pool, physical switches, not illustrated), for setting up the hardware element. 
     Note that, the function of each of the SDN controller  501 , the SON/EMS  502 , the BRM  503 , and the SON/EMS  504  shown in  FIG. 4  is implemented in one or more computers. Thus, at least one of the SON/EMS  502 , the BRM  503 , and the SON/EMS  504  may be implemented in a computer that is common to the SDN controller  501 . In other words, at least one of the SON/EMS  502 , the BRM  503 , and the SON/EMS  504  may be omitted. 
       FIG. 5  is a flowchart showing one example of a network control method according to this embodiment. In Step S 11 , the network control system  500  (SDN controller  501 ) receives resource partitioning information indicating the slicing of network resources among a plurality of MNOs. The resource partitioning information indicates the common resource partitioning of the whole of the mobile communication network including the EUTRAN  100 , the mobile backhaul  200 , and the EPC  300 . 
     In Step S 12 , the network control system  500  (SDN controller  501 ) generates an allocation configuration of radio resources of the EUTRAN  100  in accordance with the resource partitioning information. In Step S 13 , the network control system  500  (SDN controller  501 ) generates an allocation configuration of a network bandwidth of the mobile backhaul  200  in accordance with the resource partitioning information. In Step S 14 , the network control system  500  (SDN controller  501 ) generates an allocation configuration of network resources of the EPC  300  (computing resources in the case of the virtual EPC) in accordance with the resource partitioning information. Note that, the order of performing Steps S 12  to S 14  shown in  FIG. 5  is merely an example. The order of performing Steps S 12  to S 14  may be an arbitrary order which is different from the order shown in  FIG. 5 , and Steps S 12  to S 14  may be performed in parallel. 
     In Step S 15 , the network control system  500  (SON/EMS  502 , BRM  503 , and SON/EMS  504 ) applies the generated resource allocation configurations to the EUTRAN  100 , the mobile backhaul  200 , and the EPC  300 . 
     As can be seen from the above description, the network control system  500  according to this embodiment operates to enforce a resource allocation configuration to each of the EUTRAN  100 , the mobile backhaul  200 , and the EPC  300  in accordance with the resource partitioning information indicating the common resource partitioning of the whole of the mobile communication network including the EUTRAN  100 , the mobile backhaul  200 , and the EPC  300 . Thus, according to this embodiment, it is possible to reduce the burden on an operator to perform the resource allocation configuration operation individually for each of the EUTRAN  100 , the mobile backhaul  200 , and the EPC  300 . Further, according to this embodiment, it is possible to reduce configuration errors or inappropriate configurations compared with the case where an operator performs the configuration on each of the EUTRAN  100 , the mobile backhaul  200 , and the EPC  300 . This is because the operator only needs to specify the common resource partitioning of the whole of the mobile communication network including the EUTRAN  100 , the mobile backhaul  200 , and the EPC  300 . 
     Second Embodiment 
     An alternative example of the above-described first embodiment is described in this embodiment. A configuration example of a network control system according to this embodiment is the same as that shown in  FIG. 4 . In this embodiment, the resource partitioning information contains first and second resource partitioning information different from each other. The network control system  500  according to this embodiment determines which of the first and second resource partitioning information is used based on a communication status of any one of the common EUTRAN  100 , the common mobile backhaul  200 , and the common (or virtual) EPC  300 . In other words, the network control system  500  switches the resource partitioning information to be applied to the mobile communication network based on the communication status of the mobile communication network. For example, the first resource partitioning information may be used when the communication status of the mobile communication network is good, and the second resource partitioning information may be used when the communication status of the mobile communication network is degraded. The network control system  500  operates to enforce the network resource configuration to each of the common EUTRAN  100 , the common mobile backhaul  200 , and the common (or virtual) EPC  300  in accordance with the selected resource partitioning information. 
     That is, in this embodiment, it is possible to dynamically change the slicing of network resources to a plurality of MNOs based on the communication status of the mobile communication network. In one example, the MNOs may not stand on an equal level, and there may be a prioritized MNO and another MNO. In this case, a certain proportion of resources may be allocated to the prioritized MNO regardless of the communication status of the mobile communication network. On the other hand, when the communication status of the mobile communication network is degraded, a smaller proportion of resources than when the communication status is good may be allocated to the other MNO. 
     Consider the case where a point-to-point radio link using microwaves or millimeter waves (e.g., the point-to-point radio link  25  in  FIGS. 1 to 3 ) is used in the mobile backhaul  200 . The communication quality of the point-to-point radio link depends on meteorological conditions (e.g., rain, fog, haze). Rain, fog, haze and the like degrades line-of-sight visibility between two communication devices and attenuates radio signals (e.g., microwaves or millimeter waves). Therefore, a point-to-point wireless system performs adaptive processing including adjusting a modulation scheme, a code rate and the like based on the communication quality (e.g., Received Signal Strength Indicator (RSSI), Signal to Noise Ratio (SNR), or Bit Error Rate (BER)) of the point-to-point radio link. The adaptive processing that adjusts a modulation scheme, a code rate and the like based on communication quality of a radio link is called Adaptive Modulation and Coding (AMC) or link adaptation. By changing the modulation scheme, the code rate and the like, the bit rate (throughput) of the point-to-point radio link changes. 
     That is, in the case where the point-to-point radio link is used in the mobile backhaul  200 , the bit rate (throughput) of the mobile backhaul  200  tends to vary frequently. Thus, it is preferred to dynamically change the slicing of network resources to a plurality of MNOs based on the communication status (e.g., communication quality, throughput, a modulation scheme and a code rate) of the point-to-point radio link used in the mobile backhaul  200 . 
       FIG. 6  is a flowchart showing one example of the network control method according to this embodiment.  FIG. 6  shows an example where the slicing of network resources to a plurality of MNOs is dynamically changed based on a communication status of the common mobile backhaul  200 . In Step S 21 , the network control system  500  (SDN controller  501 ) acquires the communication status of the mobile backhaul  200 . The SDN controller  501  may communicate with the BRM  503  and receive a message indicating the communication status of the mobile backhaul  200  from the BRM  503 . 
     In Step S 22 , the network control system  500  (SDN controller  501 ) determines which of the first resource partitioning information and the second resource partitioning information is used based on the communication status of the mobile backhaul  200 . In Step S 23 , the network control system  500  (SDN controller  501 ) generates the resource allocation configuration for each of the common EUTRAN  100 , the common mobile backhaul  200 , and the common (or virtual) EPC  300  in accordance with the selected resource partitioning information. In Step S 24 , the network control system  500  (SON/EMS  502 , BRM  503  and SON/EMS  504 ) applies the generated resource allocation configurations to the EUTRAN  100 , the mobile backhaul  200 , and the EPC  300 . 
     Third Embodiment 
     An alternative example of the above-described first and second embodiments is described in this embodiment. A configuration example of a network control system according to this embodiment is the same as that shown in  FIG. 4 . In this embodiment, one or both of the SON/EMS  502  coupled to the common EUTRAN  100  and the SON/EMS  504  coupled to the common (virtual) EPC  300  are configured to communicate with the BRM  503  coupled to the mobile backhaul  200 . Further, one or both of the SON/EMS  502  and the SON/EMS  504  are configured to receive a message indicating a communication status of the mobile backhaul  200  from the BRM  503  and change the resource allocation configuration to a plurality of MNOs to be applied to the RAN  100  or the EPC  300  based on the communication status of the mobile backhaul  200 . 
     For example, one or both of the SON/EMS  502  and the SON/EMS  504  may receive, from the SDN controller  501  in advance, a first resource allocation configuration that is applied when the communication status of the mobile backhaul  200  is good and a second resource allocation configuration that is applied when the communication status of the mobile backhaul  200  is degraded. Then, one or both of the SON/EMS  502  and the SON/EMS  504  may switch between the first resource allocation configuration and the second resource allocation configuration based on the communication status of the mobile backhaul  200  notified from the BRM  503 . 
     According to this embodiment, it is possible to change the resource allocation to a plurality of MNOs in the EUTRAN  100  (or EPC  300 ) based on the direct communication between the SON/EMS  502  (or SON/EMS  504 ) and the BRM  503  without through the SDN controller  501 . It is thus possible to reduce a delay time required for the process of dynamically changing the resource allocation configuration in the EUTRAN  100  (or EPC  300 ) based on the communication status of the mobile backhaul  200  compared with the case of communicating through the SDN controller  501 . 
       FIG. 7  is a flowchart showing one example of the network control method according to this embodiment.  FIG. 7  shows an example where the resource allocation configuration to a plurality of MNOs in the common EUTRAN  100  is dynamically changed based on the communication status of the common mobile backhaul  200 . In Step S 31 , the SON/EMS  502  of the EUTRAN  100  receives a message indicating the communication status of the mobile backhaul  200  from the BRM  503 . In Step S 32 , the SON/EMS  502  changes the allocation configuration of radio resources to a plurality of MNOs to be applied to the EUTRAN  100  based on the communication status of the mobile backhaul  200  notified from the BRM  503 . 
     Other Embodiments 
     The case where all of the RAN, the mobile backhaul, and the core network are shared by a plurality of MNOs is mainly described in the first to third embodiments. However, the first to third embodiments may be applied also to the case where only the RAN and the mobile backhaul are shared by a plurality of MNOs as shown in  FIG. 1 . Stated differently, the first to third embodiments may be applied to the case where at least two of the RAN, the mobile backhaul, and the core network are shared by a plurality of MNOs. 
     The operation described in the third embodiment may be performed independently of the resource allocation control on the basis of the resource partitioning information described in the first and second embodiments. Stated differently, the operation described in the third embodiment is also effective in a mobile communication network and a control system that do not perform the resource allocation control on the basis of the resource partitioning information described in the first and second embodiments. 
     The methods performed in the network control system  500 , the SDN controller  501 , the SON/EMS  502 , the BRM  503  and the SON/EMS  504  described in the plurality of embodiments above may be implemented by causing a computer system including at least one processor (e.g., microprocessor, Micro Processing Unit (MPU), Digital Signal Processor (DSP)) to execute a program. To be specific, one or more programs including instructions for causing a computer system to perform algorithms described using the flowcharts and the like may be created, and the program(s) may be supplied to the computer. 
     This program(s) can be stored and provided to a computer using any type of non-transitory computer readable medium. The non-transitory computer readable medium includes any type of tangible storage medium. Examples of the non-transitory computer readable medium include magnetic storage media (such as flexible disks, magnetic tapes, hard disk drives, etc.), optical magnetic storage media (e.g., magneto-optical disks), CD-ROM (Read Only Memory), CD-R, CD-R/W, and semiconductor memories (such as mask ROM, Programmable ROM (PROM), Erasable PROM (EPROM), flash ROM, Random Access Memory (RAM), etc.). The program(s) may be provided to a computer using any type of transitory computer readable medium. Examples of the transitory computer readable medium include electric signals, optical signals, and electromagnetic waves. The transitory computer readable medium can provide the program to a computer via a wired communication line such as an electric wire or optical fiber or a wireless communication line. 
     The above embodiments are described mainly with respect to EPS. However, as mentioned earlier, those embodiments may be applied to a mobile communication network or system different from EPS, such as UMTS, GSM/GPRS system, 3GPP2 CDMA2000 system, LTE-Advanced system and the like. 
     Further, the above-described embodiments are merely an exemplification of application of the technical idea obtained by the inventors of this application. Therefore, the technical idea is not limited only to the above-described embodiments, and various changes and modifications may be made as a matter of course. 
     For example, the technical idea obtained by the inventors includes a plurality of supplementary notes described below. 
     (Supplementary Note A1) 
     A control method including: 
     receiving common resource partitioning information indicating slicing of network resources among a plurality of mobile network operators; and 
     converting the resource partitioning information into configuration information of network resources to be applied to each of the at least two of a radio access network, a mobile backhaul network, and a core network, in order to allow the plurality of mobile network operators to share the at least two networks. 
     (Supplementary Note A2) 
     The control method according to Supplementary Note A1, in which 
     the configuration information contains first configuration information regarding allocation of radio resources of the radio access network, and 
     the first configuration information affects scheduling of at least one of downlink transmission and uplink transmission in a first network element in the radio access network. 
     (Supplementary Note A3) 
     The control method according to Supplementary Note A1 or A2, in which 
     the configuration information contains second configuration information regarding allocation of a network bandwidth of the mobile backhaul network, and 
     the second configuration information affects at least one of a Virtual Private Network (VPN) configuration, a Virtual Local Area Network (VLAN) configuration, a Multi-Protocol Label Switching (MPLS) configuration, a traffic shaping configuration and a traffic scheduling configuration in a second network element in the mobile backhaul network. 
     (Supplementary Note A4) 
     The control method according to any one of Supplementary Notes A1 to A3, in which 
     the configuration information contains third configuration information for causing at least one hardware element in the core network to function as a virtualized core network node of each of the plurality of mobile operators, and 
     the third configuration information indicates allocation of computing resources of the at least one hardware. 
     (Supplementary Note A5) 
     The control method according to any one of Supplementary Notes A1 to A3, in which 
     the configuration information contains third configuration information regarding allocation of network resources of the core network, and 
     the third configuration information affects at least one of a traffic shaping configuration and a traffic scheduling configuration in a third network element in the core network. 
     (Supplementary Note A6) 
     The control method according to any one of Supplementary Notes A1 to A5, in which the resource partitioning information indicates an amount or a proportion of network resources to be partitioned to each of the plurality of mobile network operators. 
     (Supplementary Note A7) 
     The control method according to Supplementary Note A6, in which the resource partitioning information indicates an amount or a proportion of network resources to be fixedly partitioned to each of the plurality of mobile network operators and an amount or a proportion of network resources to be shared among the plurality of mobile network operators. 
     (Supplementary Note A8) 
     The control method according to any one of Supplementary Notes A1 to A5, further including: 
     enforcing a configuration to each of the at least two networks in accordance with the configuration information. 
     (Supplementary Note A9) 
     The control method according to Supplementary Note A8, in which 
     the resource partitioning information contains first resource partitioning information and second resource partitioning information different from the first resource partitioning information in slicing of network resources, and 
     the enforcing includes enforcing network resource configuration for each of the at least two networks in accordance with resource partitioning information selected from the first and second resource partitioning information based on a communication status of one of the at least two networks. 
     (Supplementary Note 10) 
     The control method according to Supplementary Note A9, in which 
     the one network is the mobile backhaul network, 
     the mobile backhaul network includes a point-to-point radio link, and 
     the communication status relates to at least one of communication quality, throughput, a modulation scheme and a code rate of the point-to-point radio link. 
     (Supplementary Note B1) 
     A network control apparatus including: 
     a mediation module configured to convert common resource partitioning information, indicating slicing of network resources among a plurality of mobile network operators, into configuration information of network resources to be applied to each of at least two of a radio access network, a mobile backhaul network, and a core network, in order to allow the plurality of mobile network operators to share the at least two networks. 
     (Supplementary Note B2) 
     The network control apparatus according to Supplementary Note B1, in which the mediation module supplies the configuration information to an enforcement module configured to enforce a configuration to any one of the at least two networks. 
     (Supplementary Note B3) 
     The network control apparatus according to Supplementary Note B2, in which the enforcement module includes an Element Management System (EMS) coupled to the radio access network or a Backhaul Resource Manager (BRM) coupled to the mobile backhaul network. 
     (Supplementary Note B4) 
     The network control apparatus according to any one of Supplementary Notes B1 to B3, in which 
     the configuration information contains first configuration information regarding allocation of radio resources of the radio access network, and 
     the first configuration information affects scheduling of at least one of downlink transmission and uplink transmission in a first network element in the radio access network. 
     (Supplementary Note B5) 
     The network control apparatus according to any one of Supplementary Notes B1 to B4, in which 
     the configuration information contains second configuration information regarding allocation of a network bandwidth of the mobile backhaul network, and 
     the second configuration information affects at least one of a Virtual Private Network (VPN) configuration, a Virtual Local Area Network (VLAN) configuration, a Multi-Protocol Label Switching (MPLS) configuration, a traffic shaping configuration and a traffic scheduling configuration in a second network element in the mobile backhaul network. 
     (Supplementary Note B6) 
     The network control apparatus according to any one of Supplementary Notes B1 to B5, in which 
     the configuration information contains third configuration information for causing at least one hardware element in the core network to function as a virtualized core network node of each of the plurality of mobile operators, and 
     the third configuration information indicates allocation of computing resources of the at least one hardware. 
     (Supplementary Note B7) 
     The network control apparatus according to any one of Supplementary Notes B1 to B5, in which 
     the configuration information contains third configuration information regarding allocation of network resources of the core network, and 
     the third configuration information affects at least one of a traffic shaping configuration and a traffic scheduling configuration in a third network element in the core network. 
     (Supplementary Note B8) 
     The network control apparatus according to any one of Supplementary Notes B1 to B7, in which the resource partitioning information indicates an amount or a proportion of network resources to be partitioned to each of the plurality of mobile network operators. 
     (Supplementary Note B9) 
     The network control apparatus according to Supplementary Note B8, in which the resource partitioning information indicates an amount or a proportion of network resources to be fixedly partitioned to each of the plurality of mobile network operators and an amount or a proportion of network resources to be shared among the plurality of mobile network operators. 
     (Supplementary Note C1) 
     A network management apparatus including: 
     an enforcement module configured to communicate with a management system of a mobile backhaul network to receive a message indicating a communication status of the mobile backhaul network, and change a configuration of network resource allocation among a plurality of mobile network operators based on the communication status of the mobile backhaul network, the configuration of network resource allocation being applied to a radio access network or a core network. 
     (Supplementary Note C2) 
     The network management apparatus according to Supplementary Note C1, in which 
     the mobile backhaul network includes a point-to-point radio link, and 
     the communication status relates to at least one of communication quality, throughput, a modulation scheme and a code rate of the point-to-point radio link. 
     (Supplementary Note C3) 
     A method performed in a management apparatus of a radio access network or a core network, the method including: 
     receiving a message indicating a communication status of a mobile backhaul network from a management system of the mobile backhaul network; and 
     changing a configuration of network resource allocation among a plurality of mobile network operators based on the communication status of the mobile backhaul network, the configuration of network resource allocation being applied to the radio access network or the core network. 
     (Supplementary Note C4) 
     The method according to Supplementary Note C3, in which 
     the mobile backhaul network includes a point-to-point radio link, and 
     the communication status relates to at least one of communication quality, throughput, a modulation scheme and a code rate of the point-to-point radio link. 
     (Supplementary Note C5) 
     A program for causing a computer to perform the method according to Supplementary Note C3 or C4. 
     This application is based upon and claims the benefit of priority from Japanese patent application No. 2013-217681, filed on Oct. 18, 2013, the disclosure of which is incorporated herein in its entirety by reference. 
     REFERENCE SIGNS LIST 
     
         
           10 ,  100  COMMON EVOLVED UTRAN (EUTRAN) 
           11  eNodeB 
           12  USER EQUIPMENT (UE) 
           20 ,  200  COMMON MOBILE BACKHAUL 
           21 ,  22  PACKET COMMUNICATION DEVICE 
           23 ,  24  PACKET COMMUNICATION DEVICE 
           25  POINT-TO-POINT RADIO LINK 
           30 A,  30 B,  32 A,  32 B EVOLVED PACKET CORE (EPC) 
           31  COMMON EPC 
           33  VIRTUALIZED CORE NETWORK 
           34 A,  34 B VIRTUAL EPC 
           300  COMMON EPC OR VIRTUAL EPC 
           500  NETWORK CONTROL SYSTEM 
           501  SOFTWARE-DEFINED NETWORK (SDN) CONTROLLER 
           502 ,  504  SELF-ORGANIZING NETWORK (SON)/ELEMENT MANAGEMENT SYSTEM (EMS) 
           503  BACKHAUL RESOURCE MANAGER (BRM) 
           600  OPERATIONS SUPPORT SYSTEM (OSS)