Description
Title of Invention: COMMUNICATION SYSTEM, BASE
STATION, COMMUNICATION METHOD, AND NONTRANSITORY
COMPUTER READABLE MEDIUM STORING
PROGRAM
Technical Field
[0001] The present invention relates to a communication system, in particular, a commu
nication system including a plurality of core network systems.
Background Art
[0002] A communication system managed by a telecommunications carrier manages the
movements of communication terminals and includes a core network(s) that includes
data relay devices and the like. Further, the communication system managed by a
telecommunications carrier prepares a gateway device for each company (i.e., each
corporate client) as a corporate service and thereby connects to a network managed by
each company through the gateway device. The gateway devices are disposed inside
the core network. A communication terminal can connect to the network of the
company to which that communication terminal belongs through the gateway device
disposed inside the communication system managed by the telecommunications
carrier.
[0003] In recent years, a connection(s) of an MTC (Machine Type Communication)
terminal(s) to a communication system has been studied. The MTC terminal is a
terminal that transmits/receives sensor information, commodity management in
formation and so on, and the amount of communication per terminal is small. A
company or the like that introduces MTC terminals collects information pieces
transmitted from a plurality of MTC terminals and analyzes the collected information.
The company or the like that introduces MTC terminals expands their services by
using the analysis result. In such cases, each company connects a number of MTC
terminals to a communication system in order to collect a large amount of information.
[0004] Note that Patent Literature 1 discloses a system in which a sensor(s), a mobile in
formation terminal(s), and an application server cooperate with each other so that a
service is provided to the mobile information terminal(s). Specifically, the mobile in
formation terminal acquires a plurality of sensor information pieces. Further, the
mobile information terminal transmits the acquired sensor information pieces to the ap
plication server. Then, the application server creates advice information based on the
sensor information transmitted from the mobile information terminal and transmits the
created advice information to the mobile information terminal. In this way, the mobile
information terminal can receive an advice service based on the sensor information.
Citation List
Patent Literature
[0005] PL: Japanese Unexamined Patent Application Publication No. 2010-1651 12
Non-Patent Literature 1
[0006] NPL1: 3GPP Technical Specification, TS 36.413 VI 1.5.0 (2013-09), clause 8.7.3
Summary of Invention
Technical Problem
[0007] However, when a number of sensors each having a communication function, a
number of MTC terminals or the like are connected to a communication system
managed by a telecommunications carrier, the following problem occurs. When a
number of sensors, a number of MTC terminals or the like update their software all at
once, the amount of traffic in the communication system sharply increases. Further, in
addition to the software updating, when MTC terminals perform communication all at
once, the amount of traffic in the communication system increases with the increase in
the number of the MTC terminals performing communication, though the amount of
communication per terminal is small. In addition to the MTC terminals and the like,
smart phones, mobile phones or the like are also connected to the communication
system. Therefore, there is a problem that when the amount of traffic by the MTC
terminals and the like sharply increases, it could cause adverse effects such as data
delays on communication using smart phones, mobile phones or the like due to the
network congestion.
[0008] An object of the present invention is to provide a communication system, a base
station, a communication method, and a program capable of eliminating an effect
caused by a sharp increase in the amount of traffic by a specific group of commu
nication terminals on the quality of the other communication terminals.
Solution to Problem
[0009] A communication system according to a first aspect of the present invention
includes: a communication terminal; a node device that selects a gateway device that
performs data communication with the communication terminal; and a base station that
selects the node device based on an identifier included in a connection request message
transmitted from the communication terminal.
[0010] A base station according to a second aspect of the present invention includes: a com
munication unit that receives a connection request message transmitted from a commu
nication terminal; and a determination unit that selects a node device from among a
plurality of node devices based on an identifier included in the connection request
message, the selected node device being to select a gateway device to which the com
munication terminal connects.
[001 1] A communication method according to a third aspect of the present invention
includes: receiving a connection request message transmitted from a communication
terminal; and selecting a node device from among a plurality of node devices based on
an identifier included in the connection request message, the selected node device
being to select a gateway device to which the communication terminal connects.
[0012] A program according to a fourth aspect of the present invention causes a computer to
execute: receiving a connection request message transmitted from a communication
terminal; and selecting a node device from among a plurality of node devices based on
an identifier included in the connection request message, the selected node device
being to select a gateway device to which the communication terminal connects.
Advantageous Effects of Invention
[0013] According to the present invention, it is possible to provide a communication system,
a base station, a communication method, and a program capable of eliminating an
effect caused by a sharp increase in the amount of traffic by a specific group of com
munication terminals on the quality of the other communication terminals.
Brief Description of Drawings
[0014] [fig.l]Fig. 1 is a configuration diagram of a communication system according to a first
exemplary embodiment;
[fig.2]Fig. 2 is a configuration diagram of a base station according to a second
exemplary embodiment;
[fig.3]Fig. 3 is a configuration diagram of a core network system according to the
second exemplary embodiment;
[fig.4]Fig. 4 shows a service identifier according to the second exemplary em
bodiment;
[fig.5]Fig. 5 shows an outline of a selection process performed by an MME according
to the second exemplary embodiment;
[fig.6]Fig. 6 shows a flow of a service identifier transmission process according to the
second exemplary embodiment;
[fig.7]Fig. 7 shows a flow of a service identifier acquisition process according to the
second exemplary embodiment;
[fig.8]Fig. 8 shows a flow of a connection request message transfer process according
to the second exemplary embodiment;
[fig.9]Fig. 9 shows a specific example of a connection request message according to
the second exemplary embodiment;
[fig.l0]Fig. 10 is a configuration diagram of a communication system according to a
third exemplary embodiment;
[fig. 1l]Fig. 11 shows a flow of an MME selection process according to the third
exemplary embodiment; and
[fig.l2]Fig. 12 is a configuration diagram of a core network system according to a
fourth exemplary embodiment.
Description of Embodiments
[00 15] (First exemplary embodiment)
Exemplary embodiments according to the present invention are explained hereinafter
with reference to the drawings. A configuration example of a communication system
according to a first exemplary embodiment of the present invention is explained with
reference to Fig. 1. A communication system shown in Fig. 1 includes a core network
system 10, a core network system 20, a base station 30, and a communication terminal
40.
[0016] Each of the core network systems 10 and 20 is a core network system for which com
munication terminals 40 allowed to connect thereto are restricted. For example, when
each of the core network systems 10 and 20 is a core network assigned to a respective
company (i.e., a respective corporate client), the communication terminals 40 allowed
to connect to that core network may be communication terminals owned by users
belonging to that company. That is, the communication terminal 40 may be configured
so that a communication terminal 40 can connect only to a core network system
assigning to a company to which its user belong and cannot connect to core network
systems assigned to the other companies.
[0017] Further, the core network system 10 or 20 may be assigned to one company or a
plurality of companies. That is, a plurality of companies may share one core network
system. Further, for example, one core network system may be assigned to each
service to be provided. When a service using MTC terminals is provided, a core
network system may be used for connection with specific MTC terminals. Further, for
example, in a region in which traffic is small or the like, a plurality of companies may
share one core network system.
[0018] The core network systems 10 and 20 include a plurality of node devices. The
plurality of node devices are used to manage the communication terminal 40 or to relay
data.
[0019] Each of the core network systems 10 and 20 is assigned a service identifier indicating
a corporate service that can be accommodated in that core network system. The
corporate service is a service that is provided inside the core network system by an
ordinary company or a telecommunications carrier, and in the core network system, the
corporate service is identified by using a service identifier. Alternatively, the corporate
service may be a service that is provided in an external network connected to the core
network system. Service identifiers assigned to their respective core network systems
are different from one core network system to another. Each of the core network
systems 10 and 20 transmits the service identifier assigned to the own system to the
base station 30.
[0020] The communication terminal 40 may be a mobile phone terminal, a smart phone
terminal, a tablet communication terminal, a personal computer having a commu
nication function, or the like. Alternatively, the communication terminal 40 may be an
MTC terminal, a compact device having a communication function, or the like.
[0021] The base station 30 is shared by the core network systems 10 and 20. The base
station 30 is disposed inside a mobile communication network and communicates with
the communication terminal 40 through a wireless line. Further, the base station 30
communicates with a node device included in the core network system 10 or 20
through a wired line or a wireless line. Further, the mobile communication network is a
network that includes the core network systems 10 and 20 and the base station 30 and
is managed by one telecommunications carrier.
[0022] The base station 30 receives a connection request message for the core network
system 10 or 20 transmitted from the communication terminal 40. For the commu
nication terminal 40, a core network system to which it can connect is determined in
advance. Assume that, for example, the core network system to which the commu
nication terminal 40 can connect is the core network system 10. In such a case, the
communication terminal 40 transmits a connection request message including in
formation for identifying the core network system 10. The identification information
included in the connection request message may be a service identifier indicating a
cooperate service or may be other identifiers.
[0023] When the base station 30 is requested to connect to the core network system 10 by
the communication terminal 40, the base station 30 transmits the connection request
message transmitted from the communication terminal 40 to the core network system
10 by using the service identifier transmitted from the core network system 10. The
"using the service identifier" means that the base station 30 selects a destination core
network system to which the connection request message should be transmitted by
specifying the service identifier.
[0024] When a service identifier is included in the connection request message, the base
station 30 may transmit the connection request message to a core network system to
which that service identifier is assigned. When an identifier different from the service
identifier is included in the connection request message, the base station 30 may
extract a service identifier associated with that identifier and transmit the connection
request message to a core network system to which the extracted service identifier is
assigned.
[0025] As explained above, by using the communication system shown in Fig. 1, the base
station 30 can identify a core network system to which the base station 30 should
connect from among a plurality of core network systems by using a service identifier
assigned to a respective one of the core network systems. The base station 30 can
select a core network system to which the communication terminal 40 can connect by
using a service identifier and transmit a connection request message transmitted from
the communication terminal 40 to the selected core network system. Further, the base
station 30 can also transmit/receive data relating to the communication terminal 40 that
is generated after the above-described connection process through the selected core
network system.
[0026] As described above, each of a plurality of core network systems disposed inside the
mobile communication system is assigned a service identifier indicating a corporate
service that can be accommodated in that core network system. As a result, the base
station 30 can determine, for each communication terminal 40, the destination of a
connection request message transmitted from that communication terminal 40. Since
the base station 30 can transfer communication data relating to a specific group of
communication terminals to a specific core network system, the base station 30 can
prevent the transfer of communication data from having an adverse effect on the other
core network systems and thereby deteriorating their communication quality even
when the amount of communication data relating to the specific group of commu
nication terminals sharply increases.
[0027] (Second exemplary embodiment)
Next, a detailed configuration example of a base station 30 according to a second
exemplary embodiment of the present invention is explained with reference to Fig. 2.
The base station 30 includes a network (NW) communication unit 31, a service
identifier holding unit 32, a terminal communication unit 33, and a determination unit
34.
[0028] The NW communication unit 3 1 communicates with a node device disposed inside a
core network system. The NW communication unit 3 1 may be used as an interface for
communicating with the node device. The NW communication unit 31 receives a
service identifier transmitted from the node device. The service identifier is an
identifier indicating a corporate service that can be accommodated in the core network
system in which the node device is disposed. The NW communication unit 3 1 outputs
the received service identifier to the service identifier holding unit 32.
[0029] The service identifier holding unit 32 associates the service identifier output from the
NW communication unit 3 1 with the core network system and manages (or stores) the
service identifier in the associated state. The service identifier holding unit 32 may be a
memory disposed inside the base station 30 or an external memory connected to the
base station 30. When the NW communication unit 31 communicates with a plurality
of core network systems and thereby receives a plurality of service identifiers, the
service identifier holding unit 32 holds the plurality of service identifiers.
[0030] The terminal communication unit 33 communicates with the communication terminal
40. The terminal communication unit 33 may be used as an interface for commu
nicating with the communication terminal 40. The terminal communication unit 33
performs wireless communication with the communication terminal 40 by using a pre
determined wireless communication scheme. The predetermined wireless commu
nication scheme may be, for example, LTE (Long Term Evolution) specified in 3GPP
(3rd Generation Partnership Project). The terminal communication unit 33 receives a
connection request message transmitted from the communication terminal 40. The
terminal communication unit 33 outputs the received connection request message to
the determination unit 34. The communication terminal 40 can transmit/receive user
data by connecting to the core network system through the base station 30. Therefore,
the communication terminal 40 transmits a connection request message in order to
connect to the core network system.
[0031] Examples of the user data include voice data, image data, and moving image data.
Further, the user data may be referred to as "U-Plane (User- Plane) data". Meanwhile,
the connection request message may be referred to as "control data". The control data
may also be referred to as "C-Plane (Control-Plane) data". Specifically, the connection
request message may be an Attach message or a TAU (Tracking Area Update)
message specified in the 3GPP.
[0032] The determination unit 34 determines a core network system to which the connection
request message output from the terminal communication unit 33 should be transmitted
by using a service identifier set in that connection request message and a service
identifier(s) held in the service identifier holding unit 32. The CPU or the like of a
computer apparatus constituting the base station 30, for example, may be used as the
determination unit 34.
[0033] Upon receiving the connection request message from the terminal communication
unit 33, the determination unit 34 extracts a service identifier set in the connection
request message. The service identifier set in the connection request message is used
when the communication terminal 40 selects a core network system to which the com
munication terminal should connect. At this point, the determination unit 34 de
termines whether or not the same service identifier as the extracted service identifier is
held in the service identifier holding unit 32. The determination unit 34 may acquire
information representing a list of service identifiers held in the service identifier
holding unit 32 from the service identifier holding unit 32 and thereby determine
whether or not the service identifier set in the connection request message is held in the
service identifier holding unit 32.
[0034] When the determination unit 34 determines that the same service identifier as the
extracted service identifier is held in the service identifier holding unit 32, the deter
mination unit 34 transmits the connection request message to a core network system
associated with the service identifier through the NW communication unit 31. The fact
that the same service identifier as the extracted service identifier is held in the service
identifier holding unit 32 indicates that the NW communication unit 3 1 can com
municate with the core network system to which that service identifier is assigned. On
the other hand, when the determination unit 34 determines that the same service
identifier as the extracted service identifier is not held in the service identifier holding
unit 32, the determination unit 34 may transmits the connection request message to a
predetermined core network system through the NW communication unit 31.
[0035] Next, configuration examples of core network systems 10A and 10B according to the
second exemplary embodiment of the present invention are explained with reference to
Fig. 3. The core network system 10B has a similar configuration to that of the core
network system 10A, and therefore its detailed explanation is omitted. Note that the
core network systems 10A and 10B may be operated by one company, or may be
shared by a plurality of companies. For example, in the case of the LTE, each of the
core network systems 10A and 10B is an EPC (Evolved Packet Core).
[0036] The core network system 10A includes an SGW (Serving GW) 11A, a PGW (Packet
Data Network GW) 12A and an MME (Mobility Management Entity) 13A. Further,
the PGW 12A is connected to a service server 14A installed in a dedicated network A.
The SGW 11A, the PGW 12A, and the MME 13A are node devices specified in the
3GPP. Examples of the dedicated network include: networks operated by companies,
ministries and agencies, and municipalities; intra-company LANs; and Ethernets
(registered trademark). In this figure, the core network system 10A includes one SGW
11A, one PGW 12A, one MME 13A, and one service server 14A. However, the core
network system 10A may include a plurality of SGWs 11A, a plurality of PGWs 12A,
a plurality of MMEs 13A, and a plurality of service servers 14A.
[0037] Further, each node device in the core network system 10A may be provided as a
VNF (Virtualized Network Function) by the telecommunications carrier. The VNF is
virtualization of a network node in which a CPU(s), a memory(s), and so on of a
physical machine(s) are shared by a plurality of companies or the like, and resources
such as a virtual CPU and a virtual memory provided to each company can be d y
namically changed.
[0038] The SGW 11A transmits user data transmitted from base stations 30A and 30B to the
PGW 12A. Further, the SGW 11A transmits user data whose destination is a communication
terminal 100 to the base station 30A and transmits user data whose destination
is a communication terminal 130 to the base station 30B. Fig. 3 shows that the commu
nication terminals 100 and 130 communicate with the core network system 10A, and
communication terminals 110 and 120 communicate with the core network system
10B.
[0039] Similarly to the SGW 11A, the PGW 12A transmits or receive user data. The PGW
12A communicates with the service server 14A disposed in the dedicated network A.
That is, the PGW 12A is a gateway device disposed on the boundary with the
dedicated network A. For example, the PGW 12A may connect to a corporate service
server or the like.
[0040] The MME 13A selects the SGW 11A that transmits/receive user data relating to the
communication terminal 100, which is connected to the MME 13A through the base
station 30A, and user data relating to the communication terminal 130, which is
connected to the MME 13A through the base station 30B. The MME 13A notifies the
base stations 30A and 30B of information about the selected SGW 11A. As a result,
for example, the base station 30A can transmit user data transmitted from the commu
nication terminal 100 to the SGW 11A. Further, the base station 30A can receive data
transmitted from the SGW 11A and transmit the received data to the communication
terminal 100. The MME 13A selects the PGW 12A as well as the SGW 1 1A.
[0041] When there are a plurality of SGWs 11A in the core network system 10A, the MME
13A may take account of the load state of each of these SGWs 11A and thereby select
a SGW 11A having a smaller (or smallest) load. Further, the MME 13A may select a
SGW 11A according to other selection criteria.
[0042] The MME 13A holds a service identifier of a service that can be accommodated in
the core network system 10A. Further, the MME 13A transmits the held service
identifier to the base stations 30A and 30B. A case where the MME 13A is shared
among a plurality of cooperate services, e.g., shared by a plurality of companies or the
like is explained hereinafter.
[0043] For example, the MME 13A holds a plurality of service identifiers relating to a
plurality of cooperate services for which the connection is allowed, and thereby is
shared among the plurality of cooperate services and the like. In this case, the MME
13A notifies the base stations 30A and 30B of the plurality of service identifiers.
[0044] Next, a specific structure of a service identifier is explained with reference to Fig. 4.
Fig. 4 shows an example in which a service identifier is set in a sub-field of an
MMEGI (MME Group ID) field included in a GUMMEI (Globally Unique MME
Identifier). The GUMMEI is identification information for an MME specified in the
3GPP. Alternatively, the service identifier may be handled as an independent in
formation element in the mobile communication system.
[0045] The GUMMEI is identification information that the MME 13 transmits to the base
station 30. The GUMMEI includes various information fields including fields for an
MCC (Mobile Country Code), an MNC (Mobile Network Code), an MMEGI, and an
MMEC (MME Code). In the MCC, a code for identifying a country is set. In the MNC,
a code for identifying a telecommunications carrier is set. The MMEGI includes subfields
in which a Service ID indicating a service identifier and a Pool ID are set.
[0046] The Pool ID is an identifier that is assigned to a plurality of MMEs in common. For
example, a common Pool ID may be assigned to a plurality of MMEs disposed in a
specific region. The plurality of MMEs to which a common Pool ID is assigned may
be referred to a MME group. That is, different Pool IDs are assigned to a group of
MMEs disposed in different regions, and the same Pool ID is assigned to a group of
MMEs disposed in the same region.
[0047] The MMEGI consists of, for example, 16 bits. When N bits (N is an integer no less
than zero) of the 16 bits are used for the Service ID, the remaining bits (16-N bits) are
assigned to the Pool ID.
[0048] The Service ID is an identifier assigned to each corporate service. By assigning a
Service ID to each core network system, a core network system used by a corporate
service is specified. When one core network system is shared among a plurality of
corporate services, Service IDs each of which is assigned to one of the plurality of
corporate services are assigned to that core network system. That is, a core network
system holds one or a plurality of Service IDs according to a corporate service(s) to
which the connection is allowed.
[0049] The MMEC is an identifier for uniquely identifying each of a plurality of MMEs to
which a common Pool ID is assigned.
[0050] The MME 13 transmits a GUMMEI with a Service ID set therein to the base station
30. The base station 30 extracts the Service ID from the GUMMEI transmitted from
the MME 13, associates the extracted GUMMEI with a core network system, and
manages (or stores) the GUMMEI in the associated state.
[0051] An outline of a process for selecting a core network system, i.e., for selecting an
MME performed by the determination unit 34 of the base station 30 is explained
hereinafter with reference to Fig. 5. In this figure, a core network system 10 includes
one MME and a core network system 20 includes three MMEs. The core network
system 10 includes an MME in which the MMEGI is 10/100 and the MMEC is 1. The
MMEGI indicates "Service ID/Pool ID". Therefore, in the MME of the core network
system 10, a value 10 is assigned to the Service ID and a value 100 is assigned to the
Pool ID.
[0052] Similarly, the core network system 20 includes: an MME in which the MMEGI is
20/100 and the MMEC is 1; an MME in which the MMEGI is 20/100 and the MMEC
is 2; and an MME in which the MMEGI is 20/100 and the MMEC is 3.
[0053] Each MME notifies the base station 30 of its MMEGI and MMEC. The base station
30 manages (or stores) the notified MMEGIs and MMECs.
[0054] Note that when the base station 30 receives a connection request message in which a
value 20 is set as a service identifier from the communication terminal 40, the base
station 30 selects one of the three MMEs in which a value 20 is set as the Service ID
and transmits the connection request message to the selected MME. In this case, the
base station 30 may select one of the three MMEs in which a value 20 is set as the
Service ID by using Weight Factors. For example, the base station 30 may selects an
MME in the ascending order of the MMECs. Alternatively, the base station 30 may
acquire the processing load states of the MMEs in advance and select an MME having
a smaller (or smallest) processing load. The base station 30 may select an MME by
using other selection processes. Further, instead of using the configuration shown in
Fig. 5, the communication system may be configured so that an MME is shared among
a plurality of corporate services. For example, one MME accommodates "MMEGI:
10/100, MMEC: 1" and "MMEGI: 20/100, MMEC: 1".
[0055] Next, a flow of a service identifier transmission process according to the second
exemplary embodiment of the present invention is explained with reference to Fig. 6.
This example is explained by using an eNB (evolved NodeB) specified in the 3GPP as
the base station 30. The eNB is a base station in conformity with an LTE (Long Term
Evolution) wireless scheme.
[0056] Firstly, the eNB transmits an SI SETUP REQUEST message to an MME (S10). For
example, upon power-on, the eNB transmits an SI SETUP REQUEST message to an
MME connected to that eNB. Note that the eNB may transmit an SI SETUP
REQUEST message to a plurality of MMEs.
[0057] Next, the MME transmits an SI SETUP RESPONSE message to the eNB (SI 1). The
MME sets a GUMMEI in the SI SETUP RESPONSE message. That is, the MME
notifies the eNB of a Service ID by transmitting an SI SETUP RESPONSE message to
the eNB. When a plurality of Service IDs are assigned to the MME, the MME notifies
the eNB of the plurality of Service IDs. The plurality of Service IDs may be
transmitted from the MME to the eNB in the form of a list of Service IDs. Note that
the outline of the SI SETUP REQUEST message and the SI SETUP RESPONSE
message shown in Fig. 6 is explained in Chapter 8.7.3 of TS36.413 VI 1.5.0 (2013-09),
which is specifications in the 3GPP. In the communication system according to the
second exemplary embodiment of the present invention, a Service ID is newly set in
the SI SETUP RESPONSE message specified in Chapter 8.7.3 of TS36.413 VI 1.5.0
(2013-09).
[0058] Next, a flow of a service identifier acquisition process according to the second
exemplary embodiment of the present invention is explained with reference to Fig. 7.
Firstly, the NW communication unit 3 1 of the eNB acquires a GUMMEI set in an SI
SETUP RESPONSE message (S21). Next, the service identifier holding unit 32
extracts a service identifier (Service ID) set in a sub-field of the MMEGI of the
GUMMEI (S22). Next, the service identifier holding unit 32 holds the extracted
Service ID (S23).
[0059] Next, a flow of a connection request message transfer process according to the
second exemplary embodiment of the present invention is explained with reference to
Fig. 8.
[0060] Firstly, the determination unit 34 receives a connection request message transmitted
from the communication terminal 40 through the terminal communication unit 33
(S31). Next, the determination unit 34 determines whether or not a Service ID is set as
a service identifier in the connection request message (S32). Next, when the deter
mination unit 34 determines that a Service ID is set in the connection request message,
the determination unit 34 extracts that Service ID (S33). Next, the determination unit
34 determines whether or not the extracted Service ID matches a Service ID held in the
service identifier holding unit 32 (S34).
[0061] When the determination unit 34 determines that the Service ID included in the
connection request message matches a Service ID held in the service identifier holding
unit 32, the determination unit 34 transmits the connection request message to an
MME of a core network system associated with the Service ID included in the
connection request message (S36). When the determination unit 34 determines that the
Service ID included in the connection request message does not match any Service ID
held in the service identifier holding unit 32 or when the determination unit 34 de
termines that no Service ID is set in the connection request message transmitted from
the communication terminal 40 in the step S32, the determination unit 34 transmits the
connection request message to a predetermined Default MME (S35). Information
about the Default MME may be stored in advance in a memory or the like disposed
inside the base station 30, or may be set in an SI SETUP RESPONSE or the like and
sent to the base station 30.
[0062] A specific example of a connection request message transmitted from the commu
nication terminal 40 in the step S31 is explained hereinafter with reference to Fig. 9.
Fig. 9 shows a state where a Service ID is set in an RRC Connection Request message
transmitted from the communication terminal 40 to the eNB. In this way, the commu
nication terminal 40 notifies the eNB of the Service ID. In Fig. 9, an example case
where the Service ID has an 8-bit length is shown.
[0063] As explained above, by using the communication system according to the second
exemplary embodiment of the present invention, the base station (eNB) can connect a
communication terminal for which a specific service identifier is set with a specific
core network system. As a result, data relating to the specific communication terminal
is transmitted through the specific core network system. Therefore, no data relating to
the specific communication terminal flows into the other core network systems. Ac
cordingly, even when the amount of data relating to the specific communication
terminal increases, the other core network systems receive no adverse effect therefrom.
[0064] Further, since the service identifier is set in a sub-field of the MMEGI of the
GUMMEI, which has been already specified in the 3GPP, the above-described con
figuration can be implemented without substantially changing the structure of existing
messages.
[0065] Further, by assigning a core network system to each corporate service, a mobile
telecommunications carrier can design a network while estimating the amount of
traffic only for ordinary users such as users of smart phones and users of mobile phone
terminals. That is, a mobile telecommunications carrier can design a mobile commu
nication network without taking account of the amount of traffic relating to commu
nication terminals and the like that connect to core network systems each of which is
assigned to a respective one of corporate services.
[0066] Further, each company can design a core network system according to the char ac
teristics of communication terminals that connect to that core network system. For
example, when only communication terminals that do not move connect to a core
network system, the cost for the core network system can be reduced by constructing a
core network system in which the movement management function is omitted. Further,
when a number of communication terminals that frequently move connect to a core
network system, the company can construct a core network system having high quality
by reinforcing the MME, the SGW, and the PGW.
[0067] (Third exemplary embodiment)
Next, a configuration example of a communication system according to a third
exemplary embodiment of the present invention is explained with reference to Fig. 10.
In this figure, a case where the communication terminal 40 performs handover
involving a change of an MME is explained.
[0068] A communication system shown in Fig. 10 includes a core network system 20, a core
network system 50, a base station 30, a base station 35, and a DNS (Domain Name
System) server 60. The core network system 20 includes an MME 2 1 and an MME 22.
Further, the core network system 50 includes an MME 51.
[0069] Further, Fig. 10 shows a state where the communication terminal 40 moves from a
communication area formed by the base station 30 to a communication area formed by
the base station 35. The communication terminal 40 moves while communicating with
the base station 30 and thus performs handover.
[0070] A Service ID assigned to the MMEs 2 1 and 22 has a value 20. Further, the Pool ID of
the MME 2 1 has a value 100 and the Pool ID of the MME 22 has a value 200. That is,
the MMEs 2 1 and 22 are disposed in different regions. The Service ID of the MME 5 1
has a value 50 and its Pool ID has a value 100. The MME 5 1 manages a region corre
sponding to the combined regions of the MMEs 2 1 and 22.
[0071] Next, a connection configuration of the communication system shown in Fig. 10 is
explained. The MME 2 1 manages the base station 30. That is, the MME 2 1 is
connected to the base station 30. The MME 22 is connected to the base station 35.
Further, the MME 5 1 is connected to the base stations 30 and 35. Further, the MMEs
2 1 and 22 is connected with the DNS server 60.
[0072] Each of the base stations 30 and 35 selects the core network system 20 or 50 as the
destination of a connection request message according to a Service ID sent from the
communication terminal 40.
[0073] Fig. 10 shows a state where the communication terminal 40 uses a value 20 as its
Service ID and connects to the MME 2 1 through the base station 30. In the abovedescribed
state, the communication terminal 40 moves to the communication area
formed by the base station 35. In this case, since the Service ID assigned to the MME
2 1 connected to the base station 30 has a value 20, the MME 22, to which the value 20
is assigned as its Service ID, serves as the MME that manages the base station 35 after
the communication terminal 40 has moved. Therefore, when the communication
terminal 40 is handed over, the MME to which the communication terminal 40
connects also changes from the MME 2 1 to the MME 22. Note that the MMEs to
which the base station 35 connects includes the MME 5 1 in addition to the MME 22.
However, since the communication terminal 40 had been connected to the MME 2 1 by
using the value 20 as its Service ID before the handover, the MME to which the com
munication terminal 40 connects is changed to the MME 22 that has a Service ID
having the same value as that of the MME 21.
[0074] The MME 22, which manages the base station 35 to which the communication
terminal 40 has been handed over, acquires subscriber information of the commu
nication terminal 40 from the MME 21. That is, the MME 2 1 transmits the subscriber
information of the communication terminal 40 to the MME 22, which manages the
base station 35 to which the communication terminal 40 has moved.
[0075] A flow of a process for selecting the MME 22 as the destination of the subscriber in
formation performed by the MME 2 1 is explained hereinafter with reference to Fig. 11.
Firstly, the MME 2 1 receives a handover (HO) request message relating to the commu
nication terminal 40 from the base station 30 (S41). Next, the MME 2 1 transmits a
message for inquiring the MME at the HO destination of the communication terminal
40 to the DNS server 60 (S42). For example, the MME 2 1 may transmit a message to
the DNS server 60 in order to inquire the MME connected to the base station 35 to
which the communication terminal 40 has moved. In this process, for example, the
MME 2 1 may transmit area information of the base station 35 to the DNS server 60.
[0076] The DNS server 60 manages (or stores), for example, information of areas and
MMEs managing those areas in a state where they are associated with each other. Note
that the DNS server 60 manages MMEs by using FQDNs (Fully Qualified Domain
Names). The DNS server 60 may also manage (or stores) Service IDs possessed by
MMEs by incorporating those Service IDs into FQDNs. For example, since a value 20
is assigned to the MME 22 as a Service ID, the DNS server 60 may define the FQDN
of the MME 22 as "sid20mmecl.epc. . . ." and manages (or stores) the defined FQSN.
Further, the DNS server 60 may define the FQDN of the MME 5 1 as
"sid50mmecl.epc. . . ." and manages (or stores) the defined FQSN.
[0077] In response to the message transmitted by the MME 2 1 for inquiring the MME at the
HO destination by using the Service ID 20 assigned to the communication terminal 40
in the step S42, the MME 2 1 receives a response massage including "sid20mmecl.epc.
. . ." and "sid50mmecl.epc " from the DNS server 60 (S43).
[0078] Next, the MME 2 1 determines whether or not there is an FQDN including a Service
ID that matches the Service ID assigned to the MME 2 1 itself (S44). When the MME
2 1 determines that there is an FQDN including a Service ID that matches the Service
ID assigned to the MME 2 1 itself, the MME 2 1 transmits subscriber information of the
communication terminal 40 to the MME 22 in which an FQDN including the same
Service ID as the Service ID assigned to the MME 2 1 itself is set (S45). When the
MME 2 1 determines that there is no FQDN including a Service ID that matches the
Service ID assigned to the MME 2 1 itself, the MME 2 1 selects one of the MMEs in
which FQSNs notified from the DNS server 60 are set and transmits subscriber in
formation of the communication terminal 40 to the selected MME (S46).
[0079] As explained above, by using the communication system according to the third
exemplary embodiment of the present invention, even when the communication
terminal performs handover involving a change of an MME, the former MME can
transmit subscribe information of the communication terminal to the destination MME
by using a service identifier.
[0080] Further, although an operation of the communication terminal 40 that is performed
when the communication terminal 40 is handed over is explained in the third
exemplary embodiment of the present invention, it is also possible to take over
subscriber information between MMEs in a similar manner at the time of TAU
(Tracking Area Update) of the communication terminal 40 involving a change of an
MME. However, in the case of the TAU, the MME 22, which manages the base station
35 to which the communication terminal 40 moves, selects the MME 21, which
manages the base station 30 from which the communication terminal 40 moves, and
acquires subscriber information from the MME 21.
[0081] In this case, similarly to the processes explained above with reference to Figs. 10 and
11, the MME 22 transmits an inquiring message to the DNS server 60 and acquires in
formation about the MME connected to the base station 30. The MME 22 selects the
MME 2 1 by using a Service ID as in the case of the handover operation.
[0082] (Fourth exemplary embodiment)
Next, a configuration example of a core network system 70 according to a fourth
exemplary embodiment of the present invention is explained with reference to Fig. 12.
The core network system 70 includes an SGSN (Serving GPRS Support Node) 7 1 and
a GGSN (Gateway GPRS Support Node) 72. Each of the SGSN 7 1 and the GGSN 72
is a node device specified in the 3GPP. Each of the SGSN 7 1 and the GGSN 72
transmits/receives user data relating to the communication terminal 40 and also
transmits/receives control data relating to the communication terminal 40.
[0083] The SGSN 7 1 is connected to the base station 30. That is, in contrast to the aboveexplained
second and third exemplary embodiments in which the base station 30
selects an MME, the base station 30 selects the SGSN 7 1 in Fig. 12. Similarly to the
first to third exemplary embodiments, the base station 30 selects the SGSN 7 1 by using
a service identifier.
[0084] As explained above, by using the communication system shown in Fig. 12, the base
station 30 can select the SGSN 7 1 by using a service identifier even in the so-called
"second generation system" or "third generation system" including the SGSN 7 1 and
the GGSN 72.
[0085] Although the present invention is described as a hardware configuration in the abovedescribed
exemplary embodiments, the present invention is not limited to the hardware
configurations. In the present invention, the processes in the base station and the MME
can be also implemented by causing a CPU (Central Processing Unit) to execute a
computer program.
[0086] In the above-described examples, the program can be stored in various types of nontransitory
computer readable media and thereby supplied to computers. The nontransitory
computer readable media includes various types of tangible storage media.
Examples of the non-transitory computer readable media include a magnetic recording
medium (such as a flexible disk, a magnetic tape, and a hard disk drive), a magnetooptic
recording medium (such as a magneto-optic disk), a CD-ROM (Read Only
Memory), a CD-R, and a CD-R/W, and a semiconductor memory (such as a mask
ROM, a PROM (Programmable ROM), an EPROM (Erasable PROM), a flash ROM,
and a RAM (Random Access Memory)). Further, the program can be supplied to
computers by using various types of transitory computer readable media. Examples of
the transitory computer readable media include an electrical signal, an optical signal,
and an electromagnetic wave. The transitory computer readable media can be used to
supply programs to computer through a wire communication path such as an electrical
wire and an optical fiber, or wireless communication path.
[0087] Note that the invention is not limited to the above-described exemplary embodiments
and various changes may be made therein without departing from the spirit and scope
of the present invention.
[0088] Although the present invention is explained above with reference to exemplary em
bodiments, the present invention is not limited to the above-described exemplary em
bodiments. Various modifications that can be understood by those skilled in the art can
be made to the configuration and details of the present invention within the scope of
the invention.
[0089] This application is based upon and claims the benefit of priority from Japanese patent
applications No. 2013-202034, filed on September 27, 2013, the disclosure of which is
incorporated herein in its entirety by reference.
Reference Signs List
[0090] 10 CORE NETWORK SYSTEM
1 1 SGW
12 PGW
13 MME
20 CORE NETWORK SYSTEM
2 1MME
22 MME
30 BASE STATION
3 1 NW COMMUNICATION UNIT
32 SERVICE IDENTIFIER HOLDING UNIT
33 TERMINAL COMMUNICATION UNIT
34 DETERMINATION UNIT
35 BASE STATION
40 COMMUNICATION TERMINAL
50 CORE NETWORK SYSTEM
5 1 MME
60 DNS SERVER
70 CORE NETWORK SYSTEM
7 1 SGSN
72 GGSN
PCT/JP2014/004628
Claims
A communication system comprising:
a communication terminal;
a node device that selects a gateway device that performs data commu
nication with the communication terminal; and
a base station that selects the node device based on an identifier
included in a connection request message transmitted from the commu
nication terminal.
The communication system according to Claim 1, further comprising a
core network system comprising the node device and the gateway
device, wherein
the core network system notifies the base station of an identifier in
dicating a corporate service that can be accommodated by the core
network system itself, and
the base station is shared by a plurality of core network systems, and
when the connection request message is transmitted from the commu
nication terminal, the base station transmits the connection request
message to a core network system to which the communication
terminal can connect based on an identifier included in the connection
request message and an identifier transmitted from the core network
system.
The communication system according to Claim 2, wherein the plurality
of core network systems comprises:
a first core network system that allows a plurality of communication
terminals possessed by a first user to connect thereto; and
a second core network system that allows a plurality of communication
terminals possessed by a second user to connect thereto.
The communication system according to Claim 2 or 3, wherein the core
network systems comprises a third core network system that allows a
plurality of communication terminals possessed by a first user and a
plurality of communication terminals possessed by a second user to
connect thereto.
The communication system according to any one of Claims 2 to 4,
wherein the base station transmits the connection request message to
the core network system associated with the identifier included in the
connection request message.
The communication system according to any one of Claims 2 to 5,
WO 2015/045296 PCT/JP2014/004628
further comprising a first base station that connects to a fourth core
network system and a second base station that connects to a fifth core
network system, wherein
when the communication terminal possessed by a user who is allowed
to connect to the fourth and fifth core network systems moves from the
first base station to the second base station,
the fifth core network system acquires information about the commu
nication terminal possessed by the user from the fourth core network
system.
[Claim 7] The communication system according to Claim 6, further comprising a
DNS server that manages a domain name including the identifier in a
state where the domain name is associated with the core network
system, wherein
when the communication terminal possessed by the user is handed over
from the first base station to the second base station,
the fourth core network system acquires a domain name of the fifth
core network system associated with an identifier transmitted from the
communication terminal from among a plurality of core network
systems connected to the second base station by using the DNS server.
[Claim 8] The communication system according to Claim 6, further comprising a
DNS server that manages a domain name including the identifier in a
state where the domain name is associated with the core network
system, wherein
when the communication terminal possessed by the user moves from
the first base station to the second base station in a state where the com
munication terminal is not communicating with the first base station,
the fifth core network system acquires a domain name of the fourth
core network system associated with an identifier transmitted from the
communication terminal from among a plurality of core network
systems connected to the first base station by using the DNS server.
[Claim 9] The communication system according to any one of Claims 2 to 8,
wherein the core network system comprises an MME or an SGSN
specified in 3GPP.
[Claim 10] The communication system according to Claim 9, wherein the MME
incorporates the identifier into an SI SETUP RESPONSE message and
transmits the SI SETUP RESPONSE message including the identifier
therein to the base station, the SI SETUP RESPONSE message being a
response signal to an SI SETUP REQUEST message transmitted from
PCT/JP2014/004628
the base station.
The communication system according to Claim 9 or 10, wherein the
identifier is set in a sub-field of an MMEGI field of a GUMMEI
comprising an MCC field, an MNC field, the MMEGI field, and an
MMEC field.
A base station comprising:
communication means for receiving a connection request message
transmitted from a communication terminal; and
determination means for selecting a node device from among a
plurality of node devices based on an identifier included in the
connection request message, the selected node device being to select a
gateway device to which the communication terminal connects.
The base station according to Claim 12, wherein
the communication means communicates with a plurality of core
network systems each comprising the node device and the gateway
device,
the communication means comprises service identifier holding means
for holding an identifier transmitted from the plurality of core network
systems through the communication means, the identifier indicating a
corporate service that can be accommodated by the core network
system, and
when the connection request message is transmitted from the commu
nication terminal, the communication means transmits the connection
request message to a core network system to which the communication
terminal can connect based on an identifier included in the connection
request message and an identifier transmitted from the core network
system.
The base station according to Claim 13, wherein when the connection
request message including the identifier is transmitted from the com
munication terminal, the communication means transmits the
connection request message to the core network system associated with
the identifier included in the connection request message.
The base station according to Claim 13 or 14, wherein the core network
system comprises an MME or an SGSN specified in 3GPP.
The base station according to Claim 15 wherein the communication
means transmits an SI SETUP REQUEST message to the MME and
receives an SI SETUP RESPONSE message including the identifier.
The base station according to Claim 15 or 16, wherein the identifier is
WO 2015/045296 PCT/JP2014/004628
set in a sub-field of an MMEGI field of a GUMMEI comprising an
MCC field, an MNC field, the MMEGI field, and an MMEC field.
[Claim 18] A communication method comprising:
receiving a connection request message transmitted from a commu
nication terminal; and
selecting a node device from among a plurality of node devices based
on an identifier included in the connection request message, the
selected node device being to select a gateway device to which the
communication terminal connects.
[Claim 19] A non-transitory computer readable medium storing a program that
causes a computer to execute:
receiving a connection request message transmitted from a communication terminal; and
selecting a node device from among a plurality of node devices based
on an identifier included in the connection request message, the
selected node device being to select a gateway device to which the
communication terminal connects.