Description
Title of Invention: COMMUNICATION SYSTEM
Technical Field
[0001] The present invention relates to a communication system and to parts and methods
thereof. The invention has particular but not exclusive relevance to wireless commu
nication systems and devices thereof operating according to the 3GPP (third generation
partnership project) standards or equivalents or derivatives thereof.
Background Art
[0002] Wireless communication systems enable users of User Equipment (UE) to com
municate with other such users via one of a number of base stations and via one or a
number of core networks. Typically, the UEs are mobile terminals, such as mobile
(cellular) telephones and the like, although the term UE may also refer to generally
stationary communication devices, such as laptop computers, web browsers, machinetype
communication devices, and the like. In the following description the term user
equipment is used, which is intended to cover any type of such user equipment (mobile
and stationary).
[0003] In an active or connected state a UE is registered with the network and has a Radio
Resource Control (RRC) connection with a base station so that the network knows to
which base station (or cell thereof) the user communication device belongs and can
transmit data to and receive data from the user communication device.
[0004] A Mobility Management Entity (MME) in the core network manages general
mobility aspects of the UEs and ensures that connectivity is maintained with the UEs,
for example as they are moving within the geographical area covered by the commu
nication system (and/or as they are handed over between base stations of the commu
nication system due to movement or changes in communication conditions). The MME
also manages the various bearers associated with the UEs by controlling the other
network nodes via which such bearers are provided. In order to do so, the MME
exchanges Non-Access Stratum (NAS) signalling messages with the UEs (and/or the
other network nodes) to manage the establishment of a communication session there
between.
Summary of Invention
Technical Problem
[0005] As part of the Long Term Evolution (LTE) of UTRAN (UMTS Terrestrial Radio
Access Network) referred to as E-UTRAN, there is a growing interest from operators
in deploying specialised Public Land Mobile Networks (PLMNs) or specialised com
munication nodes within a PLMN (such as specialised MMEs) that are dedicated for a
particular type of user equipment. This provides advantages in terms of scaling for
specific users or traffic types and isolating specific usage and/or specific traffic. Such
specialised networks also offer the advantage of being able to build simple networks
for some specialised services and more complex networks for more complex services.
This will also prevent any overload caused by one type of user from affecting other
types of users. These specialised networks are called "overlay networks" in the 3GPP.
However, providing completely separate networks for different types of user can lead
to an inefficient use of the network resources.
[0006] One aim of the invention is to provide for an efficient way to operate such overlay
networks whilst allowing load balancing between the network nodes.
Solution to Problem
[0007] According to one aspect, the present invention provides a control node for con
trolling overlay networks that use a plurality of Mobility Management Entities, MMEs,
and one or more base stations, the operator control node comprising: means for
assigning each MME to service one or more different types of user equipment, UE, or
UE traffic; and means for monitoring loading within the overlay networks; wherein
said means for assigning is arranged to reassign one or more MMEs to service another
type of UE or UE traffic in response to said means for monitoring identifying an
overload within or across said overlay networks.
[0008] In one embodiment, the means for assigning is arranged to assign one or more MME
types to each MME, each MME type defining a type of UE or a type of UE traffic that
the MME is configured to serve. The means for assigning may be arranged to assign
one or more weight factors to each MME, the weight factor indicating a processing
power of the MME relative to a processing power of the other MMEs in the overlay
networks. In this case, when the means for assigning reassigns one or more MMEs to
service another type of UE or UE traffic, the means for assigning changes one or more
weight factors associated with each of the one or more MMEs that are reassigned. In
one embodiment, the control node assigns, to each MME, a respective weight factor
for each of the one or more different types of UE or UE traffic to be serviced by the
MME.
[0009] The present invention also provides a Mobility Management Entity, MME, for use in
an overlay network, the MME comprising: means for receiving configuration data
defining one or more types of user equipment, UE, or types of UE traffic to be serviced
by the MME; and means for sending a base station with which the MME is to be a s
sociated a message that includes configuration data that identifies the one or more
types of UE or UE traffic to be serviced by the MME.
[0010] In one embodiment, the means for receiving configuration data is arranged to receive
reconfiguration data that defines one or more other types of UE or UE traffic to be
serviced by the MME and wherein the means for sending is arranged to send the recon
figuration data to the base station.
[001 1] The configuration or reconfiguration data may assign one or more MME types to the
MME, each MME type defining a type of UE or UE traffic that the MME is configured
to serve. The configuration data may comprise one or more weight factors for the
MME, each weight factor indicating a processing power of the MME in respect of a
type of UE or UE traffic to be serviced by the MME. In this case, if the MME con
figuration data is changed to assign the MME to serve another type of UE or UE
traffic, then the configuration data includes one or more modified weight factors a s
sociated with the MME.
[0012] The MME may be arranged to include said configuration data in an SI setup message
or in an MME configuration update message that is sent to the base station.
[0013] In one embodiment, the MME receives a UE attach request forwarded from said base
station, performs a location update procedure for the UE with a Home Subscriber
Server, HSS, receives subscription data for the UE from the HSS, and compares the
UE subscription data with the configuration data to determine if the MME is
configured to service the type of UE defined by said subscription data. If the MME de
termines that the MME is not configured to service the UE, the MME may send the
base station a reroute command to cause the base station to send the UE attach request
to another MME. In this case, the MME may include subscription data for the UE in
the re-route command to allow the base station to identify an MME that can service the
UE.
[0014] The present invention also provides a base station that is arranged to wirelessly com
municate with a plurality of user equipment, UE, and with a plurality of Mobility
Management Entities, MMEs, configured in overlay networks, the base station
comprising: means for receiving, from each MME, respective configuration data for
the MME, the configuration data for an MME defining one or more types of UE or UE
traffic to be serviced by the MME; means for receiving a request from a UE; means for
selecting an MME to service the request in dependence upon a type of UE or UE
traffic associated with the UE and the received MME configuration data; and means
for forwarding the request to the selected MME.
[0015] In one embodiment, the means for receiving configuration data receives recon
figuration data that defines one or more other types of UE or UE traffic to be serviced
by an MME. The configuration or reconfiguration data for an MME may assign one or
more MME types to the MME, each MME type defining a type of UE or UE traffic
that the MME is configured to serve. The configuration data for an MME may
comprise one or more weight factors for the MME, each weight factor indicating a
processing power of the MME in respect of a type of UE or UE traffic to be serviced
by the MME. In this case, if the configuration data for an MME is changed, in order to
assign the MME to serve another type of UE or UE traffic, then the configuration data
includes one or more modified weight factors associated with the MME.
[0016] The base station may receive said configuration data in an SI setup message or in an
MME configuration update message.
[0017] In one embodiment, the base station receives a UE attach request from a UE and
forwards the attach request to an MME, wherein in response to receiving a reroute
command from the MME, is arranged to use UE subscription data provided in the
reroute command and stored MME configuration data to reroute the UE attach request
to another MME that can service the UE attach request.
[0018] If the base station identifies, from the MME configuration data, multiple MMEs that
can service the UE request, the means for selecting an MME may be arranged to select
the MME in dependence upon weight factors associated with the multiple MMEs that
can service the UE request.
[0019] The present invention also provides a communication system comprising the above
described control node, a plurality of the above described MMEs, at least one of the
above described base stations and one or more user equipment, UE, for sending UE
requests to the base station for servicing by a selected one of the MMEs, selected by
the base station using MME configuration data and UE data identifying a type of UE
or a type of traffic associated with the UE.
[0020] Aspects of the invention extend to corresponding methods, and computer program
products such as computer readable storage media having instructions stored thereon
which are operable to program a programmable processor to carry out a method as
described in the aspects and possibilities set out above or recited in the claims and/or to
program a suitably adapted computer to provide the apparatus recited in any of the
claims.
[0021] Each feature disclosed in this specification (which term includes the claims) and/or
shown in the drawings may be incorporated in the invention independently, or in com
bination, with any other disclosed and/or illustrated features. In particular but without
limitation the features of any of the claims dependent from a particular independent
claim may be introduced into that independent claim in any combination or indi
vidually.
Brief Description of Drawings
[0022] Embodiments of the invention will now be described, by way of example, with
reference to the accompanying drawings:
[fig.l]Fig. 1 illustrates schematically a cellular communication system to which embodiments
of the invention may be applied;
[fig.2A]Fig. 2A is a timing diagram illustrating the way in which MME type data can
be sent from an MME to a base station forming part of the system shown in Fig. 1,
during an initial setup procedure;
[fig.2B]Fig. 2B is a timing diagram illustrating the way in which MME type data can
be sent from an MME to a base station forming part of the system shown in Fig. 1,
during a subsequent configuration update procedure;
[fig.3]Fig. 3 is a functional block diagram illustrating some of the functionality of a UE
forming part of the system shown in Fig. 1;
[fig.4]Fig. 4 is a functional block diagram illustrating some of the functionality of a
base station forming part of the system shown in Fig. 1;
[fig.5]Fig. 5 is a functional block diagram illustrating some of the functionality of a
Mobility Management Entity (MME) forming part of the system shown in Fig. 1;
[fig.6]Fig. 6 is a functional block diagram illustrating some of the functionality of an
operator control node forming part of the system shown in Fig. 1;
[fig.7]Fig. 7 is a timing diagram illustrating an exemplary way in which the system
shown in Fig. 1 can operate to allow for efficient use of the network resources shown
in Fig. 1;
[fig.8]Fig. 8 is a timing diagram illustrating the way in which the base station may
determine the type of UE from subscription information stored in the HSS forming part
of the system shown in Fig. 1;
[fig.9A]Fig. 9A illustrates the way in which MMEs may be grouped into two groups
and illustrating the way in which one or more MMEs may be reconfigured to address
loading issues within the overlay network;
[fig.9B]Fig. 9B illustrates the way in which MMEs may be grouped into two groups
and illustrating the way in which one or more MMEs may be reconfigured to address
loading issues within the overlay network and in which a weight factor for a re
configured MME is also changed; and
[fig.lO]Fig. 10 illustrates the way in which MMEs may be grouped into two groups
and illustrating the way each MME is assigned different weight factors, each a s
sociated with a different UE traffic type and illustrating the way in which a type of an
MME can be reconfigured by changing the weight factors associated therewith.
Description of Embodiments
- Overview
Fig. 1 schematically illustrates a communication network 1 in which user equipment
(UE) in this example conventional user communication devices 3- l a and 3- lb and
machine type communication (MTC) device 3-2 can communicate with other devices
via an E-UTRAN base station 5 and a core network 7. As those skilled in the art will
appreciate, two user communication devices 3-1, one MTC communication device 3-2
and one base station 5 are shown in Fig. 1 for illustration purposes, additional UEs
and/or base stations are likely to be present in a deployed system.
[0024] The base station 5 is coupled to a core network 7 and the core network 7 is also
coupled to other networks (e.g. the Internet) via one or more gateways (not shown).
The interface between the base station 5 and elements of the core network 7 might
utilise, for example, a high speed, high bandwidth communication link, such as an
optical fiber link or the like. The core network 7 includes, amongst other things, a pool
9 of mobility management entities (MMEs) 11, a Home Subscriber Server (HSS) 16
and an operator control node 18. In this illustration, the pool 9 of MMEs has four
MMEs, 11-1 to 11-4. The MMEs 1 1 manage general mobility aspects of the UEs 3 and
ensure that connectivity is maintained with the UEs 3 as they move within the geo
graphical area covered by the communication system (and/or as they are handed over
between base stations of the communication system). The MMEs 11 also manage the
various bearers associated with the UEs 3 (e.g. such as an EPS bearer and/or an
MBMS bearer) by controlling the other network nodes via which such bearers are
provided. The MMEs 11 are also responsible for ensuring that the UEs 3 receive an ap
propriate level of service (e.g. a desired bit rate) in accordance with their respective
subscription.
[0025] The HSS 16 maintains subscription specific information (e.g. subscribed services
(which might define that the UE is subscribed to an MTC network or a conventional
network etc.), associated service parameters, device capabilities, and/or the like) for
each UE 3. The HSS 16 provides such stored information to other network nodes (e.g.
the MMEs 11) as needed.
[0026] In this embodiment, the MMEs 11 in the pool 9 are arranged in separate groups, with
the MMEs in each group being configured to service a particular type of UE traffic (for
example conventional UE traffic, MTC UE traffic, SDT (small data transmission)
traffic, roaming traffic etc.) - and in this way the operator core network 7 is operating
overlay networks specialised for different types of UE 3. For ease of illustration two
groups 9-1 and 9-2 of MMEs are illustrated in Fig. 1, with the MMEs in the first group
9-1 (MMEs 11-1 and 11-2) being configured to serve conventional UEs 3-1 and with
the MMEs in the second group 9-2 (MMEs 11-3 and 11-4) being configured to serve
MTC type UEs 3-2. The operator control node 18 is responsible for configuring the
MMEs 11 into the different groups. When the MME 11 first connects with the base
station 5, the MME 11 informs the base station of its MME type. As illustrated in Fig.
2A, this MME type information may be provided to the base station 5 within a new In
formation Element (IE) (MME_TYPE) of the existing S1 setup procedure (which is
defined in TS 36.413, Section 9.1.8.5) or in any other message transmitted over the SI
interface from the MME 11 to the base station 5. The base station 5 stores this MME
type information for each of the MMEs 11 with which it has a connection, so that the
base station 5 can use the stored MME type information to select an appropriate MME
1 1 for a given UE 3.
[0027] In this embodiment, the operator control node 18 monitors the network traffic from
the different types of UEs 3 and can dynamically re-configure the MMEs 11 - to
change the groups in which they belong, in order to make efficient use of the network
resources (in this case the MMEs 11). For example, if at a given point in time the
operator control node 18 detects that there is a surge of traffic from MTC type UEs 3-2
that are connected with the base station 5, then it can, for example, re-configure MME
11-2 to serve MTC type UEs 3-2 instead of (or in addition to) conventional UEs 3-1.
When this happens, the reconfigured MME 11-2 informs the base station 5 of its r e
configuration, for example, as illustrated in Fig. 2B, using a new Information Element
IE (MME_TYPE) in the existing MME Configuration Update message (which is
defined in TS 36.413, Section 8.7.5) or within any other message transmitted over the
SI interface from the MME 11-2 to the base station 5. The base station 5 stores the
new MME type for the re-configured MME 11-2 and accordingly will allocate MTC
type UEs to that reconfigured MME 11-2. This will therefore make available ad
ditional network resources (MME resources) for dealing with the changing network
conditions.
[0028] As indicated above, the re-configuration may not replace the original MME type - it
may simply define that the MME 11-2 can handle MTC UEs 3-2 as well as con
ventional UEs 3-1. In this case, the base station 5 can assign both types of UE 3 to the
same MME 11.
[0029] With regard to how the base station 5 chooses which MME 11 within a particular
group 9 to assign to a particular UE, the 3GPP standards already define MME load
balancing mechanisms when multiple MMEs are available. In particular, in accordance
with the current load balancing mechanisms, each MME 11 within a pool is provided
with a weight factor (WF) that depends on its processing power compared to the other
MMEs in the same pool 9. The MME 11 transmits its weight factor to the base station
5 when it establishes a connection with the base station 5. Thus if MME 11-1 has twice
the processing power of MME 11-2, then its weight factor will be twice the weight
factor for MME 11-2; and so using the weight factors, the base station 5 will cause
twice as many UEs to be passed to MME 11-1 than to MME 11-2. Or if MME 11-1
has the same processing power as MME 11-2, then they will have the same weight
factor and so the base station 5 will assign the UEs to the two MMEs 11-1 and 11-2 in
equal proportions. As will be described in more detail below, the same weight factor
load balancing mechanism can be used for the MMEs in each group 9-1 and 9-2 or a
modified weight factor mechanism can be used to increase further the efficient use of
the network resources in overlay network deployments.
[0030] Before describing the operation of the invention in further detail, a brief description
will now be given of the different components of the system shown in Fig. 1.
[003 1] - User Equipment
Fig. 3 is a functional block diagram illustrating some of the functionality of a UE 3
shown in Fig. 1. As shown, the UE 3 has a transceiver circuit 3 1 that is operable to
transmit signals to and to receive signals from a base station 5 via one or more antenna
33. The UE 3 has a controller 37 to control the operation of the UE 3, which is
controlled, in this embodiment, by software running in memory 39. For user commu
nication device type UEs 3-1, the UE will have all the usual functionality of a con
ventional user communication device (such as a user interface 35). For MTC type UEs
3-2, no user interface may be needed. The software running in memory 39 may be preinstalled
in the memory 39 and/or may be downloaded via the communication network
or from a removable data storage device (RMD), for example.
[0032] As shown in Fig. 3, these software instructions include, among other things, an
operating system 4 1 and a communication control module 43. The memory also stores
other UE identification data 45 that identifies the UE 3 to the core network 7.
[0033] The communication control module 43 handles (e.g. generates, sends and receives)
control signals for controlling the connections between the UE 3 and other user com
munication devices, such as the base station 5. When establishing a connection with
the base station 5, the communication control module 43 sends the UE identification
data 45 to the base station 5. This information allows the base station 5 to identify the
type of UE and to select an appropriate MME 11 from the pool 9 of MMEs coupled to
the base station 5.
[0034] - Base station
Fig. 4 is a functional block diagram illustrating some of the functionality of the base
station 5 shown in Fig. 1. As shown, the base station 5 has a transceiver circuit 5 1 that
is operable to transmit signals to and to receive signals from UEs 3 via one or more
antenna 53 and that is operable to transmit signals to and to receive signals from nodes
within the core network 7 via the network interface 55. The base station 5 has a
controller 57 to control the operation of the base station 5. The controller 57 is a s
sociated with a memory 59 and is coupled to the transceiver circuit 51. Software may
be pre-installed in the memory 59 and/or may be downloaded via the communication
network or from a removable data storage device (RMD), for example.
[0035] The controller 57 is configured to control the overall operation of the base station 5
by, in this example, program instructions or software instructions stored within the
memory 59. As shown, these software instructions include, among other things, an
operating system 61, a UE communication control module 63, an MME commu
nication control module 65 and an MME selection module 66. The memory 59 is also
used to store UE identification data 67, MME type data 68 and MME WF (Weight
Factor) data 69 received from the UEs/MMEs.
[0036] The UE communication control module 63 handles (e.g. generates, sends and
receives) control signals for controlling the connections between the base station 5 and
the UEs 3. Similarly, the MME communication control module 65 handles (e.g.
generates, sends and receives) control signals for controlling the connections between
the base station 5 and the MMEs 11.
[0037] The MME selection module 66 selects an MME 11 to service a given UE 3 using the
UE identification data for the UE 3, the MME type information 68 and the MME WF
data 69 stored in memory 59. In some embodiments, the MME selection module 66
can determine the type of UE 3 directly from the corresponding UE identification data
received from the UE 3. In other embodiments, the base station 5 needs to use the UE
identification data received from the UE 3 to retrieve data indicating the type of UE
from user profile data stored in the HSS 18.
[0038] - Mobility management entity
Fig. 5 is a functional block diagram illustrating some of the functionality of each of
the Mobility Management Entities 1 1 shown in Fig. 1. As shown, the MME 1 1 has a
transceiver circuit 7 1 that is operable to transmit signals to and to receive signals from
other communication nodes (such as the base station 5 and the operator control node
18) via a network interface 75. The MME 11 has a controller 77 to control the
operation of the MME 11. The controller 77 is associated with a memory 79 and is
coupled to the transceiver circuit 71. Software may be pre-installed in the memory 79
and/or may be downloaded via the communication network or from a removable data
storage device (RMD), for example.
[0039] The controller 77 is configured to control the overall operation of the MME 11 by, in
this example, program instructions or software instructions stored within the memory
79. As shown, these software instructions include, among other things, an operating
system 81, a base station communication control module 83, and an operator control
node communication control module 85. The memory 79 also stores currently
configured MME type data 87 and MME WF data 89.
[0040] The base station communication control module 83 handles (e.g. generates, sends
and receives) control signals for controlling the communications between the MME 11
and the base station 5. Similarly, the control node communication control module 85
handles (e.g. generates, sends and receives) control signals for controlling the commu
nications between the MME 11 and the operator control node 18. When new MME
type data 87 or new MME WF data 89 is received from the operator control node 18,
this data is stored in memory 79 and the base station communication control module 83
generates an appropriate MME configuration update message (or other base station
control message) for sending to the base station 5 which includes the new MME type
data 87 and/or the new MME WF data 89.
[004 1] - Operator Control Node
Fig. 6 is a functional block diagram illustrating some of the functionality of the
operator control node 18 forming part of the system 1 shown in Fig. 1. This operator
control node may provide the specific functionality described herein or it may form
part of a more general Operations and Maintenance (O&M) control node. As shown,
the operator control node 18 has a transceiver circuit 9 1 that is operable to transmit
signals to and to receive signals from other network nodes (such as the base station 5
and the MMEs 11) via a network interface 95. The operator control node 18 has a
controller 97 to control the operation of the operator control node 18. The controller 97
is associated with a memory 99 and is coupled to the transceiver circuit 91. Software
may be pre-installed in the memory 99 and/or may be downloaded via the commu
nication network or from a removable data storage device (RMD), for example.
[0042] The controller 97 is configured to control the overall operation of the operator
control node 18 by, in this example, program instructions or software instructions
stored within the memory 99. As shown, these software instructions include, among
other things, an operating system 101, a network monitoring module 103, and an MME
configuration module 105. The memory 99 also holds MME type configuration data
107 that defines the current configuration of the MMEs 11 in terms of the type of UEs
they each are configured to service; and MME WF configuration data 108 that defines
the currently configured weight factors for the MMEs 11. The memory 99 also holds
operator policy data 107 that defines the way in which the operator control node 18
should configure the MMEs 11 to meet the policy requirements of the network
operator for a given network condition (loading). This operator policy data 107 might
define, for example, the loading limits on individual MMEs 11 before reconfiguration
is required etc.
[0043] The network monitoring module 103 is responsible for monitoring traffic and general
loading within the operator network (base stations 5, MMEs 11 etc). Based on the
monitored network conditions, the MME configuration module 105 may reconfigure
one or more of the MMEs 11. For example, in the scenario discussed above, if the
network monitoring module 103 detects an increase in MTC UEs, then the MME con
figuration module 105 may reconfigure one or more of the MMEs 11 that are currently
servicing only conventional UEs 3-1 to also service (or to instead only service) MTC
type UEs 3-2. The MME configuration module 105 may also change the weight factor
for one or more of the MMEs 11, again to control the loading on one or more of the
MMEs 11. If an MME 11 is to be reconfigured, the MME configuration module 105
sends the MME 1 1 to be reconfigured a configuration update message that includes the
new MME type data or the new MME WF data.
[0044] In the above description, the user communication device 3, the base station 5, the
mobility management entity 11, and the operator control node 18 are described for ease
of understanding as having a number of discrete modules (such as the communications
control modules, the monitoring module, the reconfiguration module etc.). Whilst these
modules may be provided in this way for certain applications, for example where an
existing system has been modified to implement the invention, in other applications,
for example in systems designed with the inventive features in mind from the outset,
these modules may be built into the overall operating system or code and so these
modules may not be discernible as discrete entities. These modules may also be im
plemented in software, hardware, firmware or a mix of these.
[0045] - Operation
A description of the operation of this embodiment will now be described with
reference to Fig. 7 which shows a timing diagram illustrating a sequence of numbered
steps that may be performed in an exemplary operation in the present embodiment.
[0046] In step 1, the MME 11-1 transmits an MME configuration update message to the
base station 5. This configuration update message contains an MME type IE that
designates that MME 11-1 is specialised for handling conventional UEs 3-1.
[0047] In step 2, the MME 11-3 transmits an MME configuration update message to the
base station 5. This configuration update message contains an MME type IE that
designates that MME 11-3 is specialised for handling MTC type UEs 3-2.
[0048] Steps 3 and 4 show that signalling from conventional UEs 3-1 are directed, by the
base station 5 (in accordance with the stored MME type information and the type of
UE from which the signalling is received) towards MME 11-1 and steps 5 and 6 show
that signalling from MTC UEs 3-1 are directed (in accordance with the stored MME
type information and the type of UE from which the signalling is received) towards
MME 11-3. If necessary, the base station 5 will identify the type of UE from UE sub
scription information held in the HSS 16 using identification information provided by
the UE 3.
[0049] For simplicity, Fig. 7 does not show configuration of MMEs 11-2 and 11-4. Where
multiple MMEs of the same type are coupled to the base station (as in the system i l
lustrated in Fig. 1), the base station 5 uses the weight factors associated with the
MMEs 11 in each group 9 for load balancing during the MME selection process (as
defined in TS23.401).
[0050] In this illustration, at some point after this initial configuration, the load on MME
11-1 becomes unacceptably high (above a certain threshold, e.g. 95%) whereas the
load on MME 11-3 is quite low (e.g. 5%). The operator control node 18 detects this
situation and decides to take corrective action in accordance with its stored operator
policy data 107. In this case, it reconfigures the MME1 1-3 so that it will handle com
munications relating to conventional and MTC UEs 3. The actions of the operator
control node 18 are not illustrated in Fig. 7 to avoid over complicating the Figure.
Once the MME 11-3 has been reconfigured by the operator control node 18, the MME
11-3 sends the base station, in step 7, an MME configuration update message including
an MME type indicating that MME 11-3 is designated to handle conventional UE
traffic and MTC UE traffic. Upon receipt of this configuration update message, the
base station 5 updates its stored MME type data 68 for MME 11-3. Thereafter the base
station 5 will use both MME 11-1 and MME 11-3 for handling conventional UEs 3-1
(as shown in steps 8a and 8b). This leads to a reduction of the load on MME 11-1, as
shown in Fig. 7.
[0051] If at a later point in time, the loading on MME 11-3 exceeds a defined threshold (in
this example 80%) and the MME 11-1 has some available spare capacity, then the
operator control node 18 reconfigures MME 11-3 to handle MTC UEs 3-2 only. In this
case, once reconfigured, the MME 11-3 sends, in step 10, another configuration update
message to the base station 5 informing the base station 5 that it is now an MTC only
type of MME 11. Accordingly, the base station 5 will update its stored MME type data
68 for MME 11-3 and as a result, subsequently received conventional signalling (in
step 10) is passed to MME 11-1 and not to MME 11-3. This will therefore reduce the
loading on MME 11-3 as illustrated.
[0052] As discussed above, if the base station 5 is unable to determine directly the type of
UE 3 from the information received from the UE 3 when the request is received, the
base station 5 will use UE identification data that is received to determine the service
to which the UE has subscribed from the subscription data stored in the HSS for that
UE. This subscription data will inform the base station 5, for example, if the UE 3 has
subscribed to an MTC service or a conventional service etc. The way in which this in
formation is obtained in an example operation is illustrated in Fig. 8.
[0053] As shown in Fig. 8, in step 21, MMEs 11-1 is configured to serve conventional UEs
3-1 and in step 22, MME 11-3 is configured to serve MTC UEs 3-2. At step 23, a UE
3-2 with a subscription for the MTC overlay network initiates an attachment to the
base station 5 by sending an attach request message. In this embodiment, this initial
request does not include any data that allows the base station 5 to determine directly
what service the UE has subscribed to, and therefore, the base station 5 selects a
default MME (in this case MME 11-1) and forwards the attach request message to it.
[0054] In steps 25 and 26, MME 11-1 accesses the HSS 16 in accordance with the normal
attach procedure and along with providing the usual location update for the UE 3-2,
retrieves the UE's subscribed network (e.g. core network (CN) type) information from
the HSS. The MME 11-1 compares the received CN type with its own currently
defined MME type data 87 and in this case the types do not match. Therefore, MME
11-1 identifies that the UE Attach Request must be re-routed to another MME 11; and
so the MME 11-1 sends, in step 27, the base station 5 a re-route command that includes
the CN type information retrieved from the HSS 16 for the UE 3-2 that sent the attach
request. In step 28, the base station 5 uses the CN type information in the received re
route command to find an appropriate MME 11 to which the attach message should be
forwarded (by comparing the received CN type data with the MME type data 68 that it
has stored in its memory 59 and identifying a match). In this case, the identified MME
is MME 11-3 and so, in step 29, the base station 5 forwards the attach request message
to the selected MME 11-3 that is configured to serve MTC UEs 3-2.
[0055] - MME TYPE & MME WF
The provision of this new MME type information impacts on the effect of the
existing MME weight factor that is used for load balancing between MMEs (in a single
network - rather than in overlay networks). The way in which this new MME type
impacts the existing load balancing will now be explained with reference to Fig. 9A
which considers an example system with the base station 5 being connected to four
MMEs 11 of an MME Pool. Initially, (as illustrated in the left hand side of Fig. 9A)
two MMEs 11 are designated for MTC traffic (in this example MMEs 11-1 and 11-2)
and two MMEs 11 are designated for conventional traffic (in this example MMEs 11-3
and 11-4). For load balancing purposes each MME 11 is assigned a weight factor (WF)
that indicates the relative processing capacity of that MME 11 with respect to the other
MMEs in the pool (in accordance with TS36.413, section 9.2.3.17). Thus in the
scenario illustrated in Fig. 9A, MMEs 11-1, 11-2 and 11-3 are of the same capacity
(WF=50) whereas MME 11-4 has twice the capacity (WF=100). Therefore, based on
these weight factors, the base station 5 will balance the traffic in the following way:
- MTC type traffic is balanced between MME 11-1 and MME 11-2 (in equal pro
portions);
- Conventional type traffic is balanced between MME 11-3 and MME 11-4 (with
twice as much traffic being directed towards MME 11-4 than to MME 11-3).
[0056] If, because of overloading on the conventional MMEs 11-3 and 11-4, the operator
control node 18 decides to provide more processing power for conventional traffic, it
may make, for example, MME 11-2 available for both types of traffic (MTC and con
ventional) - as illustrated in the right hand side of Fig. 9A. In this case, however, the
weight factors remain the same, and therefore, the base station 5 will balance the traffic
in the following way:
- MTC type traffic is balanced between MME 11-1 and MME 11-2 (in equal pro
portions);
- Conventional traffic is now balanced between MME 11-2, MME 11-3 and MME
11-4 (with twice as much traffic being directed towards MME 11-4 than to MME 11-2
or to MMEll-3).
[0057] Thus, in this scenario the same weight factor of MME 11-2 is used by the base
station 5 to control the amount of both types of traffic that is passed to MME 11-2.
This may lead to an overloading of the MME 11-2. One way to reduce this problem is
to change the WF for any MME 11 that is reconfigured to provide service to multiple
types of UE traffic. For example, in the above illustration, the operator control node 18
may also decide (at the same time as it changes the MME type of MME 11-2 to con
ventional and MTC) to reduce the weight factor associated with MME 11-2 - for
example to a weight factor of 25. This will mean that MME 11-2 will have the same
overall traffic limit as before - but for the two different traffic types. This scenario is i l
lustrated in Fig. 9B. In particular, with this arrangement, the base station 5 will balance
the traffic in the following way:
- The MTC type traffic is balanced between MME 11-1 and MME 11-2 (with twice
as much traffic going to MME 11-1 than to MME 11-2);
- The conventional traffic is now balanced between MME 11-2, MME 11-3 and
MME 11-4 (with twice as much traffic being directed towards MME 11-4 than to
MME 11-3 and with twice as much traffic being directed towards MME1 1-3 than to
MME 11-2). In this way, MME 11-1 will receive two thirds of all MTC traffic; MME
11-2 will receive a third of all MTC traffic and one seventh of all conventional traffic;
MME 11-3 will receive two sevenths of all conventional traffic; and MME 11-4 will
receive four sevenths of all conventional traffic. This should reduce the likelihood of
MME 11-2 quickly becoming overloaded because of the change of MME type.
[0058] The way in which the operator control node 18 changes the MME types and changes
any weight factors (to increase or decrease them depending on the loads to the MMEs
in the MME Pool 9) depends on the operator policy data 109 - which will be specific to
each network operator.
[0059] An alternative, but more flexible, solution to the interaction between the MME type
and the MME WF is to provide a different weight factor for each type of traffic that an
MME 11 is configured to serve. Thus each MME 11 would be assigned multiple MME
weight factors - a weight factor per MME Type (per traffic type). For example, an
MME 11 that is of MTC and Conventional type would have two different weight
factors - an mtc_weight_factor and a conv_weight_factor. This would allow more
flexibility for the operator in scheduling the traffic towards the MMEs of mixed type
which would allow for better load balancing across the overlay networks. Such a
scenario is illustrated in Fig. 10. In Fig. 10, initially (as shown in the left hand side of
Fig. 10) MME 11-1 and MME 11-2 are of type MTC with mtc_wf = 50 and conv_wf =
0 (no conventional traffic served by MME 11-1 and MME 11-2). MME 11-3 is of con
ventional type with mtc_wf = 0 and conv_wf = 50 whereas MME 11-4 is also of con
ventional type but has twice the power of the other MMEs in the MME Pool - and so it
has mtc_wf = 0 and conv_wf = 100.
[0060] In this case, if the operator decides to allow more processing power for conventional
traffic, it may make, for example, MME 11-2 available for both types of traffic by
modifying the MME weight factors to mtc_wf = 25 and conv_wf = 25, for MME 11-2.
In this case the operator can set a desired relation between the weight factors of the
same MME 11 for better overload control across the different types of networks (or
network nodes) within the overlay networks. For example, instead of making the
weight factors for mtc and conventional traffic the same, the operator control node 18
may instead modify the MME weight factors for MME 11-2 to mtc_wf = 10 and
conv_wf = 40 - which will increase the amount of conventional traffic sent to MME
11-2. Again, the operator control node 18 may increase or reduce the different weight
factors based on the specific operator's policy for overload control. Indeed, with this al
ternative embodiment, the different values assigned to the different weight factors of
each MME will effectively assign the different MMEs to different types of traffic; and
there is no need, in this alternative embodiment, for the MMEs 11 to send the base
station 5 separate MME type data 68 - as it is defined already by the presence or
absence and/or the values of all the weight factors associated with the MME 11. An
MME that is specialised for a specific type of UE will only have the weight factor cor
responding to that traffic type set at a value that is not equal to zero - any other weight
factors associated with that MME will be zero (in this case only one weight factor may
be used for a specialised MME).
[0061] - Advantages
The systems described above offer a number of advantages. In particular, the main
embodiment described above allows for a flexible and dynamic MME Type con
figuration and selection in overlay networks and for load balancing between the
overlay networks. A network operator (the control node 18) can, at any point of time
(based on the current network load, traffic pattern, emergencies and maintenance
events or any other potential use case that could lead to overload to one or more
networks within the overlay networks architecture), re-configure the specialisation of
the MMEs (via the new information element (MME Type)) and change also their
weight factor (decrease or increase) so that the overload of certain network(s) within
the overlay networks is avoided.
[0062] The alternative embodiment described above with reference to Fig. 10 allows for
different weight factors per MME Type which leads to a more flexible and so
phisticated load balancing across the overlay networks and within each overlay
network. It allows for proportional load balancing between the constituent overlay
networks and MMEs 11.
[0063] In brief the embodiments allow for dynamic and optimised overload control within
each overlay network and across all the overlay networks.
[0064] - Modifications and Alternatives
Detailed embodiments have been described above. As those skilled in the art will ap
preciate, a number of modifications and alternatives can be made to the above em
bodiments whilst still benefiting from the inventions embodied therein. By way of il
lustration only a number of these alternatives and modifications will now be described.
[0065] In the above embodiments, the MMEs were divided into two groups of MMEs - one
for servicing conventional UEs and one for servicing MTC UEs. As those skilled in the
art will appreciate, the available MMEs may be divided into many more groups,
depending on the number of different types of UEs defined within the particular
operator network.
[0066] In the above embodiments, the communication devices, such as the base stations, the
UEs and the MMEs used 3GPP LTE communication technology. However, it will be
appreciated that other communication technologies may be used instead.
[0067] In the above embodiments, the user equipment comprises mobile (cellular) commu
nication devices or machine type communication devices. Other types of UE can be
defined, such as roaming UEs, SDT UEs etc., and a different overlay network may be
provided for handling each type of UE.
[0068] In the above description, the UEs, the base station, the mobility management entity,
and the control node are described for ease of understanding as having a number of
discrete functional components or modules. Whilst these modules may be provided in
this way for certain applications, for example where an existing system has been
modified to implement the invention, in other applications, for example in systems
designed with the inventive features in mind from the outset, these modules may be
built into the overall operating system or code and so these modules may not be di s
cernible as discrete entities.
[0069] In the above embodiments, a number of software modules were described. As those
skilled in the art will appreciate, the software modules may be provided in compiled or
un-compiled form and may be supplied to the user communication devices, the base
station, the mobility management entity, and the PDN gateway as a signal over a
computer network, or on a recording medium. Further, the functionality performed by
part or all of this software may be performed using one or more dedicated hardware
modules or circuits. However, the use of software modules is preferred as it facilitates
the updating of the user communication devices, the base station, the mobility
management entity, and the operator control node in order to update their func
tionalities.
[0070] - Glossary of 3GPP terms:
DL - Downlink
eNB - Evolved NodeB, E-UTRAN base station
EPC - Evolved Packet Core
EPS - Evolved Packet System
E-UTRA - Evolved UMTS Terrestrial Radio Access
E-UTRAN - Evolved UMTS Terrestrial Radio Access Network
GPRS - General Packet Radio System
HSS - Home Subscriber Server
LTE - Long Term Evolution (of UTRAN)
MME - Mobility Management Entity
NAS - Non-Access-Stratum
(E-)RAB - (EPS-) Radio Access Bearer
RRC - Radio Resource Control
SDT - Small Data Transmission
UE - User Equipment
UL - Uplink
UMTS - Universal Mobile Telecommunications System
[0071] This application is based upon and claims the benefit of priority from United
Kingdom patent application No. 1403819.4, filed on March 4, 2014, the disclosure of
which is incorporated herein in its entirety by reference.
Reference Signs List
[0072] 1 communication network
3- la, 3- lb user communication device
3-2 MTC device
5 base station
7 core network
9 pool
9-1, 9-2 group
11-1, 11-2, 11-2, 11-4 MME
16 HSS
18 operator control node
31 transceiver circuit
33 antenna
user interface
controller
memory
operating system
communication control module
UE identification data
transceiver circuit
antenna
network interface
controller
memory
operating system
UE communication control module
MME communication control module
MME selection module
UE identification data
MME type data
MME WF data
transceiver circuit
network interface
controller
memory
operating system
base station communication control module
operator control node communication control module
MME type data
MME WF data
transceiver circuit
network interface
controller
memory
1 operating system
3 network monitoring module
5 MME configuration module
MME type configuration data
8 MME WF configuration data
9 operator policy data
PCT7JP2015/000778
Claims
A control node for controlling overlay networks that use a plurality of
Mobility Management Entities, MMEs, and one or more base stations,
the operator control node comprising:
means for assigning each MME to service one or more different types
of user equipment, UE, or different types of UE traffic; and
means for monitoring loading within the overlay networks; and
wherein said means for assigning is arranged to reassign one or more
MMEs to service another type of UE or UE traffic in response to said
means for monitoring identifying an overload within or across said
overlay networks.
The control node according to claim 1, wherein said means for
assigning is arranged to assign one or more MME types to each MME,
each MME type defining a type of UE or UE traffic that the MME is
configured to serve.
The control node according to claim 1 or 2, wherein said means for
assigning is arranged to assign one or more weight factors to each
MME, the weight factor indicating a processing power of the MME
relative to a processing power of the other MMEs in the overlay
networks.
The control node according to claim 3, wherein when said means for
assigning reassigns one or more MMEs to service another type of UE
or UE traffic, the means for assigning is arranged to change one or
more weight factors associated with each of the one or more MMEs
that are reassigned.
The control node according to claim 4, arranged to assign, to each
MME, a respective weight factor for each of the one or more different
types of UE or UE traffic to be serviced by the MME.
A Mobility Management Entity, MME, for use in an overlay network,
the MME comprising:
means for receiving configuration data defining one or more types of
user equipment, UE, or different types of UE traffic to be serviced by
the MME; and
means for sending a base station with which the MME is to be a s
sociated a message that includes configuration data that identifies the
one or more types of UE or UE traffic to be serviced by the MME.
The MME according to claim 6, wherein the means for receiving conPCT7JP2015/
000778
figuration data is arranged to receive reconfiguration data that defines
one or more other types of UE or UE traffic to be serviced by the MME
and wherein the means for sending is arranged to send the recon
figuration data to the base station.
The MME according to claim 6 or 7, wherein said configuration or re
configuration data assigns one or more MME types to the MME, each
MME type defining a type of UE or UE traffic that the MME is
configured to serve.
The MME according to any of claims 6 to 8, wherein said configuration
data comprises one or more weight factors for the MME, each weight
factor indicating a processing power of the MME in respect of a type of
UE or UE traffic to be serviced by the MME.
The MME according to claim 9, wherein if said MME configuration
data is changed to assign the MME to serve another type of UE or UE
traffic, then the configuration data includes one or more modified
weight factors associated with the MME.
The MME according to any of claims 6 to 10, wherein said MME is
arranged to include said configuration data in an SI setup message or in
an MME configuration update message.
The MME according to any of claims 6 to 11, arranged to receive a UE
attach request forwarded from said base station, to perform a location
update procedure for the UE with a Home Subscriber Server, HSS, to
receive subscription data for the UE from the HSS, and to compare the
UE subscription data with the configuration data to determine if the
MME is configured to service the type of UE defined by said sub
scription data.
The MME according to claim 12, wherein if the MME determines that
the MME is not configured to service the UE, the MME is arranged to
send the base station a reroute command to cause the base station to
send the UE attach request to another MME.
The MME according to claim 13, wherein the MME is arranged to
include subscription data for the UE in the re-route command to allow
the base station to identify an MME that can service the UE.
A base station arranged to wirelessly communicate with a plurality of
user equipment, UE, and with a plurality of Mobility Management
Entities, MMEs, configured in overlay networks, the base station
comprising:
means for receiving, from each MME, respective configuration data for
PCT7JP2015/000778
the MME, the configuration data for an MME defining one or more
types of UE or UE traffic to be serviced by the MME;
means for receiving a request from a UE;
means for selecting an MME to service the request in dependence upon
the type of UE or the type of traffic associated with the UE and the
received MME configuration data; and
means for forwarding the request to the selected MME.
The base station according to claim 15, wherein the means for
receiving configuration data is arranged to receive reconfiguration data
that defines one or more other types of UE or UE traffic to be serviced
by an MME.
The base station according to claim 15 or 16, wherein the configuration
or reconfiguration data for an MME assigns one or more MME types to
the MME, each MME type defining a type of UE or UE traffic that the
MME is configured to serve.
The base station according to any of claims 15 to 17, wherein the con
figuration data for an MME comprises one or more weight factors for
the MME, each weight factor indicating a processing power of the
MME in respect of a type of UE or UE traffic to be serviced by the
MME.
The base station according to claim 18, wherein if the configuration
data for an MME is changed, in order to assign the MME to serve
another type of UE or UE traffic, then the configuration data includes
one or more modified weight factors associated with the MME.
The base station according to any of claims 15 to 19, wherein said base
station is arranged to receive said configuration data in an S1 setup
message or in an MME configuration update message.
The base station according to any of claims 15 to 20, arranged to
receive a UE attach request from a UE and to forward the attach request
message to an MME, wherein in response to receiving a reroute
command from the MME, is arranged to use UE subscription data
provided in the reroute command and stored MME configuration data
to reroute the UE attach request to another MME that can service the
UE attach request.
The base station according to any of claims 15 to 21, wherein if the
base station identifies, from the MME configuration data, multiple
MMEs that can service the UE request, the means for selecting an
MME is arranged to select the MME in dependence upon weight
PCT7JP2015/000778
factors associated with the multiple MMEs that can service the UE
request.
A communication system comprising a control node of any of claims 1
to 5, a plurality of MMEs according to any of claims 6 to 14, at least
one base station according to any of claims 15 to 22 and one or more
UEs for sending UE requests to the base station for servicing by a
selected one of the MMEs, selected by the base station using MME
configuration data and UE data identifying a type of traffic associated
with the UE.
A user equipment, UE, for use in an overlay network, the UE being
configured to send a UE request to the base station for servicing by a
selected one of a plurality of MMEs, selected using MME con
figuration data and UE data identifying a type of UE or a type of traffic
associated with the UE.
A method performed by a control node that controls overlay networks
that use a plurality of Mobility Management Entities, MMEs, and one
or more base stations, the method comprising:
assigning each MME to service one or more different types of user
equipment, UE, or UE traffic; and
monitoring loading within the overlay networks;
wherein said assigning reassigns one or more MMEs to service another
type of UE or UE traffic in response to said monitoring identifying an
overload within or across said overlay networks.
The method according to claim 25, wherein said assigning assigns one
or more MME types to each MME, each MME type defining a type of
UE or UE traffic that the MME is configured to serve.
The method according to claim 25 or 26, wherein said assigning
assigns one or more weight factors to each MME, the weight factor in
dicating a processing power of the MME relative to a processing power
of the other MMEs in the overlay networks.
The method according to claim 27, wherein when said assigning
reassigns one or more MMEs to service another type of UE or UE
traffic, the method further comprises changing one or more weight
factors associated with each of the one or more MMEs that are r e
assigned.
The method according to claim 28, comprising assigning, to each
MME, a respective weight factor for each of the one or more different
types of UE or UE traffic to be serviced by the MME.
PCT7JP2015/000778
A method performed by a Mobility Management Entity, MME, that
forms part of an overlay network, the method comprising:
receiving configuration data defining one or more types of user
equipment, UE, or UE traffic to be serviced by the MME; and
sending a base station with which the MME is to be associated a
message that includes configuration data that identifies the one or more
types of UE or UE traffic to be serviced by the MME.
The method according to claim 30, wherein the receiving configuration
data receives reconfiguration data that defines one or more other types
of UE or UE traffic to be serviced by the MME and further comprising
sending the reconfiguration data to the base station.
The method according to claim 30 or 31, wherein said configuration or
reconfiguration data assigns one or more MME types to the MME, each
MME type defining a type of UE or UE traffic that the MME is
configured to serve.
The method according to any of claims 30 to 32, wherein said con
figuration data comprises one or more weight factors for the MME,
each weight factor indicating a processing power of the MME in
respect of a type of UE or UE traffic to be serviced by the MME.
The method according to claim 33, wherein if said MME configuration
data is changed to assign the MME to serve another type of UE or UE
traffic, then the configuration data includes one or more modified
weight factors associated with the MME.
The method according to any of claims 30 to 34, wherein said sending
includes said configuration data in an SI setup message or in an MME
configuration update message.
The method according to any of claims 30 to 35, comprising receiving
a UE attach request from a base station, performing a location update
procedure for the UE with a Home Subscriber Server, HSS, receiving
subscription data for the UE from the HSS, and comparing the UE sub
scription data with the configuration data to determine if the MME is
configured to service the type of UE defined by said subscription data.
The method according to claim 36, wherein if said comparing de
termines that the MME is not configured to service the UE, the method
further comprises sending the base station a reroute command to cause
the base station to send the UE attach request to another MME.
The method according to claim 37, further comprising including sub
scription data for the UE in the re-route command to allow the base
PCT7JP2015/000778
station to identify an MME that can service the UE.
A method performed by a base station that is arranged to wirelessly
communicate with a plurality of user equipment, UE, and with a
plurality of Mobility Management Entities, MMEs, configured in
overlay networks, the method comprising:
receiving, from each MME, respective configuration data for the MME,
the configuration data for an MME defining one or more types of UE or
UE traffic to be serviced by the MME;
receiving a request from a UE;
selecting an MME to service the request in dependence upon a type of
UE or UE traffic associated with the UE and the received MME con
figuration data; and
forwarding the request to the selected MME.
The method according to claim 39, further comprising receiving recon
figuration data that defines one or more other types of UE or UE traffic
to be serviced by an MME.
The method according to claim 39 or 40, wherein the configuration or
reconfiguration data for an MME assigns one or more MME types to
the MME, each MME type defining a type of UE or UE traffic that the
MME is configured to serve.
The method according to any of claims 39 to 41, wherein the con
figuration data for an MME comprises one or more weight factors for
the MME, each weight factor indicating a processing power of the
MME in respect of a type of UE or UE traffic to be serviced by the
MME.
The method according to claim 42, wherein if the configuration data for
an MME is changed, in order to assign the MME to serve another type
of UE or UE traffic, then the configuration data includes one or more
modified weight factors associated with the MME.
The method according to any of claims 39 to 43, comprising receiving
said configuration data in an SI setup message or in an MME con
figuration update message.
The method according to any of claims 39 to 44, further comprising
receiving a UE attach request from a UE and forwarding the attach
request message to an MME, receiving a reroute command from the
MME, using UE subscription data provided in the reroute command
and stored MME configuration data to reroute the UE attach request to
another MME that can service the UE attach request.
WO 2015/133078 PCT/JP2015/000778
[Claim 46] The method according to any of claims 39 to 45, identifying, from the
MME configuration data, multiple MMEs that can service a UE
request, and wherein said selecting an MME selects the MME in de
pendence upon weight factors associated with the multiple MMEs that
can service the UE request.
[Claim 47] A control node for controlling overlay networks that use a plurality of
Mobility Management Entities, MMEs, and one or more base stations,
the operator control node comprising:
an MME configuration module that assigns each MME to service one
or more different types of user equipment, UE, or UE traffic; and
a network monitoring module that monitors loading within the overlay
networks; and
wherein said MME configuration module is arranged to reassign one or
more MMEs to service another type of UE or UE traffic in response to
said network monitoring module identifying an overload within or
across said overlay networks.
[Claim 48] A Mobility Management Entity, MME, for use in an overlay network,
the MME comprising:
a control node communication control module that receives con
figuration data defining one or more types of user equipment, UE, or
UE traffic to be serviced by the MME; and
a base station communication control module that sends a base station
with which the MME is to be associated a message that includes con
figuration data that identifies the one or more types of UE or UE traffic
to be serviced by the MME.
[Claim 49] A base station arranged to wirelessly communicate with a plurality of
user equipment, UE, and with a plurality of Mobility Management
Entities, MMEs, configured in overlay networks, the base station
comprising:
an MME communication control module that receives, from each
MME, respective configuration data for the MME, the configuration
data for an MME defining one or more types of UE or UE traffic to be
serviced by the MME;
a UE communication control module that receives a request from a UE;
an MME selection module that selects an MME to service the request
in dependence upon a type of UE or UE traffic associated with the UE
and the received MME configuration data; and
wherein the MME communication control module is arranged to
WO 2015/133078 PCT/JP2015/000778
forward the request to the selected MME.
[Claim 50] A computer implementable instructions product comprising computer
implementable instructions for causing a programmable commu
nications device to perform the method of any of claims 25 to 46.