Note: Descriptions are shown in the official language in which they were submitted.
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Systems and Methods for Prioritizing Network Selection to
Achieve PLMN Continuity When Moving Between Networks of
Different Types
Field
The application relates to moving between networks
having different network types.
Background
Cellular coverage has historically been provided
by wireless access networks having base stations, and
operating using cellular protocols. Examples of cellular
radio access networks include GSM/EDGE RADIO ACCESS NETWORK
(GERAN) Universal Terrestrial Radio Access Network (UTRAN),
or Evolved Universal Terrestrial Radio Access Network
(E-UTRAN).
Wi-Fi is a popular wireless networking technology
that uses radio waves to provide wireless high-speed
Internet and network connections. The Wi-Fi Alliance, the
organization that owns the Wi-Fi (registered trademark) term
specifically defines Wi-Fi as any "wireless local area
network (WLAN) products that are based on the Institute of
Electrical and Electronics Engineers' (IEEE) 802.11
standards." Wi-Fi is an example of a technology that
provides wireless IP connectivity.
GAN stands for Generic Access Network (GAN). It
is designed to complement traditional GERAN, UTRAN, or E-
UTRAN cellular radio access network coverage by allowing
coverage for cellular subscribers to be extended to areas
covered by Wi-Fi networks. This is achieved by tunnelling
Non Access Stratum (NAS) protocols between the MS (mobile
station) and the Core Network over an IP network. These
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protocols run over top the IP protocol provided by the WLAN
network or other radio IP based network. A network node in
GAN is referred to as a GANC (GAN controller), and it is
used to provide the interworking between the radio IP based
network and the traditional GERAN, UTRAN, or E-UTRAN
cellular radio access networks.
The MS may have a preferred mode of operation vis-
a-vis the use of GAN, or not, that can be configured by the
user, or by the operator through various mechanisms. This
information is stored in the "GAN Mode Selection Preferences
Field". The modes of operation that the MS may use are
GERAN/UTRAN-only, GERAN/UTRAN-preferred, GAN-preferred, and
GAN-only.
If the mode selection preference for the MS is
GERAN/UTRAN-preferred, then the MS accesses voice or data
services in GERAN/UTRAN as long as there is a suitable GERAN
cell or a suitable UTRAN cell available. If the MS cannot
find a suitable GERAN or UTRAN cell to camp on, and the MS
has successfully registered with a GANC, then the MS
switches to GAN mode. Being "camped on" a particular cell
means that in idle mode, the MS has assessed the surrounding
cells that it can see and has chosen a cell which will offer
it a suitable radio connection. From the radio propagation
point of view it is desirable that the MS camps on a cell
with the lowest path loss, however there may be other
reasons or criteria by which the MS chooses a particular
cell. As the user moves, the camped on cell may become
unsuitable. This situation will generate a cell re-
selection. (see 3GPP 45.008 Section 6: Idle Mode Tasks).
When the MS in GAN mode is able to find a suitable
GERAN/UTRAN cell to camp on, or the MS has de-registered or
loses connectivity with the GANC over the generic IP access
network, the MS returns to GERAN/UTRAN mode.
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If the mode selection preference for the MS is
GAN-preferred, when the MS has successfully registered with
the GAN over the generic IP access network, the MS switches
to GAN mode and stays in this mode as long as the GAN is
available. When the MS deregisters, or otherwise loses
connectivity with the GAN, the MS switches to GERAN/UTRAN
mode.
In a given cellular coverage area, multiple
different service providers may be available. Each service
provider has a respective network referred to as a PLMN
(public land mobile network). Similarly, each PLMN may have
an associated set of GANC5 that control interworking between
the PLMN and the GAN, effectively extending the coverage of
the service provider. A GANC is typically associated with
one PLMN. However a GANC could be associated with multiple
PLMN5.
When a MS is attempting PLMN selection in GAN
mode, only PLMN5 available via GAN may be considered. The
MS may be able to connect via several GANC5 that are
associated with different PLMN5. When the MS moves into
GAN, it will ultimately register with a GANC and in doing so
has also registered with the associated PLMN for access
while in GAN.
A GANC is a physical node. Each GANC can play one
or more of three logical roles: provisioning GANC, Default
GANC, Serving GANC.
A GAN-capable PLMN (an operator that has GANC
nodes associated with its network), stores in memory of MSs
the IP address or FQDN (fully qualified domain name)
associated with a GAN Controller that can be used to access
its network. The GANC that is addressed in memory is
referred to as the "provisioning GANC" for that network.
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Initially, discovery requests are made to the provisioned
GANC. This "provisioned" GANC gives access to the HPLMN
(home PLMN) and will let the MS know the address of a
default GANC (also in the HPLMN). The HPLMN is the PLMN
that the mobile device is subscribed to. The default GANC
may or may not be the same as the provisioning GANC.
The MS uses the address of the default GANC in
order to attempt to register to it. The default GANC is the
logical network node for GAN services that is always
connected to the HPLMN. The default GANC can accept, reject
or redirect registration attempts from the MS. The GANC
that ultimately provides access to the MS is called the
serving GANC. The default GANC is the logical role of a
GANC in the HPLMN, and it may redirect an MS performing the
GAN Registration Procedure to a preferred Serving GANC.
The Serving GANC and the Default GANC may be the same
entity, in which case no redirection is required.
Note that the GANC's physical location is up to
the network operator. The MS connects with the GANC by
tunnelling over the internet, so the GANC's physical
location is irrelevant and meaningless to the MS. A GANC is
like the network operator's VPN server that allows mobile
stations to connect to the core network (i.e. SGSN5 for data
and MSC5 for voice) from any internet access point.
The process of registering with GAN starts with
the transmission of a GA-RC REGISTER REQUEST sent from the
MS to the GANC. The MS may or may not be required to select
a GANC as part of the registration process. If, during GAN
registration, the MS has a choice amongst two or more GANC-
PLMN pairs, then GANC selection takes place. The MS may be
informed of available GANC-PLMN pairs via a GAN PLMN list.
The GAN PLMN list can be sent to the MS as part of the GA-RC
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REGISTER REDIRECT message, which is sent to the MS from the
Default GANC in response to a GA-RC REGISTER REQUEST.
A handover refers to switching the point of
connectivity with the network, be it cellular or GAN while
5 communications are active, also referred to as being in
dedicated mode (while an active voice call or data session
is in progress). A handover into GAN refers to
disconnecting from a cellular base station or (e)Node B or
equivalent, and connecting to a GANC, while a handover out
of GAN refers to disconnecting from a GANC and connecting to
a cellular base station or (e)Node B or equivalent. This is
to be contrasted with roving into and out of GAN which
refers to idle mode transitions.
The signalling between PLMN5 to support seamless
handovers exists but in practice this is used very rarely,
because coordination and synchronization between two
networks is considered to be too much overhead. As a
result, having to switch PLMN5 during an active
communication session most often results in a
discontinuation of that communication session. This results
in a poor user experience.
Summary
According to one broad aspect, the application
provides a method comprising: determining a PLMN list of
networks of a first network type such that a PLMN on the
list that also supports a second network type is
prioritized; configuring a MS (mobile station) with the PLMN
list.
According to another broad aspect, the application
provides a network node comprising: a transmitter; a network
determiner configured to determine a PLMN list of networks
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of a first network type such that a PLMN on the list that
also supports a second network type is prioritized and to
cause the transmitter to transmit a configuration of the
PLMN list to a MS (mobile station).
According to another broad aspect, the application
provides a mobile station comprising: a first wireless
access radio for accessing networks of a first network type;
a second wireless access radio for accessing networks of a
second network type; a network selector configured to
perform network selection using a PLMN list within listing
networks of a first network type such that a PLMN on the
list that also supports a second network type is
prioritized.
Brief Description of the Drawings
Figure 1 is a network diagram depicting an example
GAN access scenario;
Figure 2 is a flowchart of a method for MSs to
transmit PLMN continuity preference information;
Figure 3 is a flowchart of a method of a GANC to
receive GAN PLMN continuity preference information;
Figure 4 is flowchart of a method of moving into
GAN based on GAN PLMN continuity preference information;
Figure 5 is a flowchart of a method for a GANC to
process registration requests having regard to GAN PLMN
continuity preference information;
Figure 6 is a flowchart of a method of achieving
PLMN continuity;
Figure 7 is a block diagram of another mobile
device; and
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Figure 8 is a network diagram depicting an example
access scenario.
Detailed Description
When moving into or out of GAN, it is possible for
the PLMN associated with the Serving GANC to be different
than the PLMN that the MS registers to in cellular mode.
If the PLMN changes during a transition between GAN and
cellular, then the call or data session is typically
released because of lack of coordination between PLMN5, and
this results in a poor experience for the user.
Specifically, suppose a MS has an active call or data
session while operating in a cellular coverage area using a
first PLMN that will be referred to as PLMN1. The MS then
moves into a GAN coverage area and registers with a GANC
associated with PLMN2 which is different from PLMN1. When
this occurs, the call or data session is released.
Similarly, suppose a MS has an active call or data session
while operating in a GAN coverage area using a first PLMN
that will be referred to as PLMN1. The MS then moves into a
cellular coverage area and connects to a base station or
(e)Node B or equivalent associated with PLMN2 which is
different from PLMN1. When this occurs, the call or data
session is typically released.
The issue of PLMN continuity for GAN is especially
applicable when the MS is moving between GAN and the
cellular network (in either direction), and is relevant to
GERAN/UTRAN-preferred (more generally cellular-preferred)
and GAN-preferred modes of operation since GAN-only and
GERAN/UTRAN-only (cellular-only) modes do not allow for such
transitions. The issue of PLMN continuity for GAN also
applies to other situations, such as when the MS is moving
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between GANs or between different radio access networks in
general.
In some embodiments described below, the MS may
request the Default GANC to send a GAN PLMN list. This
procedure may allow the MS to obtain a list of available
GANC-PLMN pairs, for example when its registration attempt
on the stored Serving GANC or Default GANC resulted in a
PLMN mismatch. This may be done, for example, using a GA-RC
REGISTER UPDATE uplink message.
Referring to Figure 1, shown is a network diagram
depicting an example GAN access scenario. Shown is a MS 10,
a plurality of WLAN access points (AP) 22,24,26, a network
cloud 28, a GANC 30, and a legacy GANC 40. At the instant
depicted, the MS 10 has wireless connectivity to access
point 22. More generally, the discussion presented herein
applies to GAN access scenarios in which there are any
number of MSs, any number of access points, and any number
of GANC5. Network cloud 28 represents any network
connectivity between the access points 22,24,26 and the
GANC5 30,40. This may for example include parts of the
public Internet and or private networks.
The MS 10 has a cellular radio 12 through which
cellular communication takes place. The MS 10 has a WLAN
radio 14 for connecting to WLAN access points. The MS 10
has a GANC selector 16 responsible for deciding if and when
to attempt to register with GAN, and for deciding which GANC
to register with. The MS has a GAN PLMN continuity
preference storage element 18 for storing a GAN PLMN
continuity preference (GPCP). The preference can be stored
in any suitable form; specific examples include a token or
an identifier. This storage element can be in internal or
external memory of any appropriate form.
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GANC 30 is a GANC that is configured to recognize
the GAN PLMN continuity preference information when received
from a MS such as MS 10. The GANC 30 has a registration
request handler 32 responsible for processing registration
requests. The registration request handler 32 has a GAN
PLMN continuity preference processing function 34 which
takes into account a GAN PLMN continuity preference received
from a MS. In some embodiments, the GANC 30 also includes a
GAN PLMN continuity preference configurator 36 for
configuring the GAN PLMN continuity preference on a MS. In
some embodiments, the GANC 30 also includes GPCP storage 38
for storing the GPCP of MSs. This might be for the purpose
of configuring the GPCP of MSs in which case the
configurator 36 sends this information to the MS. In
another example, the GPCP storage 38 is for storing the GPCP
received from an MS, for example in association with an IP
address or other identifier of the MS.
Legacy GANC 40 is a GANC which is not configured
to recognize the GAN PLMN continuity preference
information.
Some embodiments provide a mechanism for the MS to
send the GAN PLMN continuity preference to a GANC, and for a
GANC such as GANC 30 to receive the GAN PLMN continuity
preference information. Some embodiments provide mechanisms
for a GANC such as GANC 30 to make use of such GAN PLMN
continuity preference information, and some embodiments
provide mechanisms for a MS such as MS 10 to make use of the
GAN PLMN continuity preference information.
In operation, when the MS decides to register with
GAN, it starts by sending a registration message to the
default GANC. The MS 10 transmits the GAN PLMN continuity
preference, for example in a registration message or post-
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registration message. The behaviour of the MS and the
default GANC is a function of whether or not the default
GANC is a configured to recognize the GAN PLMN continuity
preference (as is the case for GANC 30), or the default GANC
5 is not configured to recognize the GAN PLMN continuity
preference (as is the case for legacy GANC 40).
Where the default GANC is configured to recognize
the GAN PLMN continuity preference, it will process the
registration request as a function of the GAN PLMN
10 continuity preference by selecting between a) accepting the
registration request, b) rejecting the registration request,
and c) performing a registration redirect. Many examples of
this processing are detailed below.
The MS receives a response from the default GANC,
and handles the response based on a PLMN continuity
preference for the MS. Many examples of this are detailed
below.
The HPLMN is the network to which a mobile station
is subscribed. An EHPLMN (equivalent HPLMN) is another
network that can provide service to the mobile station in
substantially the same manner as the HPLMN, for example
without incurring roaming charges. HPLMN and EHPLMN
relationships may occur as a result of network operator
mergers, for example. No PLMN discontinuity results from
being registered on the HPLMN for cellular and an EHPLMN for
GAN.
The RPLMN (registered PLMN) is the PLMN with which
a mobile station is registered in cellular. An equivalent
RPLMN (ERPLMN) is a PLMN that is equivalent to the RPLMN in
the sense that ERPLMN provides service to the mobile station
in substantially the same manner as the RPLMN. No PLMN
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discontinuity results from being registered on the HPLMN for
cellular and an EHPLMN for GAN, or vice versa.
GAN PLMN Continuity Preference Indication
A mechanism is provided that allows the MS to be
able to communicate to the network whether or not it
requires or would prefer to maintain PLMN continuity. In
some embodiments, the information from this field is used in
various registration messages, as described more fully
below.
Preference for PLMN continuity refers generally to
preferences for a MS in respect of the maintenance of
continuity of PLMN when moving into or out of GAN. This
preference will be referred to as the GAN PLMN continuity
preference (GPCP) introduced above. In some embodiments,
the GPCP is used to indicate one of four preferences. These
four specific preferences are described below. More
generally, the number of possible preferences, and their
definitions, may be different than this specific example.
While in idle mode or dedicated mode, the MS may
also move between GANC5. The preference for PLMN continuity
may extend to movement between GANC5. If the MS if moving
to a different GANC from the current serving GANC, the MS
will attempt to try and register with a different target
GANC while still maintaining the IPsec tunnel to its current
serving GANC. As part of the registration procedure the MS
will learn which PLMN the target GANC is associated with.
If the PLMN associated with the target GANC is acceptable
(according to the MSs GPCP field), then the MS completes the
registration with the target GANC. If the MS is in
dedicated mode, it then performs a handover to the new GANC.
If it is in dedicated mode or idle mode it subsequently de-
registers from the previous serving GANC. If the PLMN
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associated with the target GANC is not acceptable (according
to the MSs GPCP field), then the MS looks for other GANC5
and repeats the process just described. Alternately the MS
may trigger the serving GANC to send it a GAN PLMN list
using an extension to the REGISTER UPDATE MESSAGE (if in
idle mode) or the CLASSMARK change procedure (if in
dedicated mode) and may subsequently re-select based on this
list.
PLMN Continuity Required
Generally, the PLMN Continuity Required preference
indication is used to indicate that the MS requires PLMN
continuity.
This is, for example, the case when the MS wants
to be registered in GAN on a PLMN that is the same as the
RPLMN or that is an equivalent PLMN to the RPLMN (i.e.
EPLMN). In some embodiments, when the MS cannot register in
GAN on such a PLMN, this preference indication is used to
indicate that PLMN re-selection in cellular should be
performed in order to permit the MS to stay on the same PLMN
in GAN and cellular modes. Another example of when this may
be used is when the MS is engaged in an active session such
as but not limited to a voice call and when the MS needs to
handover the call to the GANC, for example when the coverage
in cellular is too weak to maintain the call but the
coverage in GAN is sufficient, it can do so without dropping
the call.
PLMN Continuity Preferred
The MS may "prefer" PLMN continuity and can use
the PLMN Continuity Preferred indication. In this case,
PLMN continuity is not essential for registration with GAN,
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but if there is any way that it can be achieved this will be
done.
GANC Associated with HPLMN or EHPLMN required
The GANC Associated with HPLMN or EHPLMN Required
indication is the case where the user (or the user's
operator) wants to force the MS to use a GANC associated
with the HPLMN or EHPLMN and not to use GAN at all if this
cannot be realized. (This would include the Default GANC or
another GANC that is associated with the HPLMN or EHPLMN).
This may be the case where there are specific roaming or
billing reasons not to allow the MS to connect to a GANC
associated with a VPLMN (Visited Public Land Mobile
Network). Note that this preference may result in a PLMN
continuity mismatch.
No Preference
The No Preference indication is used to indicate
that there is no restriction on the GANC used. For example,
the MS might behave according to 3GPP TS 44.318. In this
case it is completely up to the network whether to register
the MS in a way that it has PLMN continuity or not, and the
MS will accept whatever situation it finds itself in.
Configuring the GAN PLMN Continuity Preference for a MS
In a specific example, two bits can be used to
indicate one of the four possible GAN PLMN continuity
preferences described above, although it is of course to be
clearly understood that other data structures can
alternatively be employed.
The GAN PLMN Continuity preference is stored on
the MS. The GAN PLMN continuity preference is stored in
memory (removable or not) on the MS in any appropriate form,
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such as, but not limited to a bit flag / token / identifier
or other field, list, or data structure. In some
embodiments, proprietary fields in the MS may be used to
store the GAN PLMN continuity preference. In various
possible implementations, this may be provisioned during
manufacture/device setup, provisioned by a user via user
interface on the MS, or provisioned by the network. The
operator may provision the settings using OMA DM (Open
Mobile Alliance Device Management), OTA (over the air)
provisioning, ANDSF (Access Network Discovery and Selection
Function) or any other standardized or proprietary
mechanism. These provisioning mechanisms may make use of
USSD (unstructured supplementary service data), SMS (short
message service), Cell Broadcast, MBMS, generic IP pipe or
other transport mechanism.
In some embodiments, the preference indication may
exist as an EF (Elementary File) on the Universal Subscriber
Identity Module (USIM). An example of this file is as
described below, and is referred to as EFGPCP (GAN PLMN
Continuity Preference).
Table 1 below shows an example of an EF containing
an indication to the MS regarding the preference for
maintaining PLMN continuity when moving in either direction
between GAN and cellular networks and optionally also when
moving between GANC5.
Table 1: PLMN Continuity Preference EF
Identifier: Structure: Optional
'xxxx' transparent
File size: 1 byte Update activity: low
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Access Conditions:
READ PIN
UPDATE ADM
DEACTIVATE ADM
ACTIVATE ADM
Bytes Description M/ Length
0
1 GAN PLMN Continuity 0 1 byte
Preference
- GAN PLMN Continuity Preference:
Contents:
MS PLMN Continuity Preference
Coding:
- '00' - No preference
- '01' - GANC Associated with HPLMN or
EHPLMN required
- '10' - MS prefers PLMN continuity
- '11' - MS requires PLMN continuity
- All other values are reserved for future
use.
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In yet another example, GAN PLMN continuity
preference information may be provisioned on the MS as part
of the GAN Mode Selection Preferences Field. In this case,
the network operator may be able to change this preference
in a field in a message such as the REGISTER REDIRECT
message. An example of this is detailed below. If the GAN
PLMN Continuity Preference is updated to indicate "No
Preference", or if the EF is not there as in the case of a
legacy system, then the MS will follow PLMN selection
techniques without regard to maintaining GAN PLMN
continuity, for example, as currently described in 3GPP TS
43.318 and 3GPP TS 44.318.
Table 2 below shows the GA-GC Register Redirect message
structure from 3GPP TS 44.318 modified to include a GAN PLMN
Continuity Preference Field. The GANC may use this message
to redirect the MS to another GANC. In this case the message
will contain the Serving GANC-SEGW and Serving GANC
information. The message may also contain information about
one or more PLMN identities where the MS may be served while
in GAN coverage.
Table 2: GA-RC REGISTER REDIRECT message content
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IEI Information Type/ Presence Format Length Value Notes
Element Reference
Length Length M V 2
Indicator indicator
11.1.1.1
GA-RC Protocol M V 1~ 0000
Protocol Discriminator
Discriminator 11.1.1.2
Skip Skip M V 0000
Indicator indicator
11.1.1.3
GA-RC Message Type M V 1
REGISTER 11.1.1.4
REDIRECT
Message Type
9 Serving GANC- IP Address C TLV 7-19
SEGW IP 11.2.9
address
Serving GANC- Fully C TLV 5-258
SEGW FQDN Qualified
Domain/Host
Name
11.2.10
97 Serving GANC IP Address C TLV 7-19
IP address 11.2.9
98 Serving GANC Fully C TLV 5-258
FQDN Qualified
Domain/Host
Name
11.2.10
103 Serving GANC Communication 0 TLV 4
TCP port port
number 11.2.25
67 Serving GANC Serving GANC 0 TLV 3
table table
indicator indicator
11.2.67
69 GAN PLMN List GAN PLMN List C TLV n
11.2.69
xxx GAN PLMN PLMN 0 TLV 3
Continuity Continuity
Preference Preference,
11.2.xxx
where the GAN PLMN Continuity Preference IE is, for example,
as in Table 3 below:
Table 3: GAN Continuity Preference IE
8 7 6 5 4 3 2 1
PLMN Continuity Preference IEI octet
1
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Length of PLMN Continuity Preference octet
contents 2
Spare CP octet
3
where CP (Continuity Preference) is defined, for example, as
in Table 4 below. Table 4: CP Definition
CP Continuity Preference (octet 3)
Bit
Bit
1 0
1 1 MS requires PLMN
continuity
1 0 MS prefers PLMN
continuity
0 1 GANC Associated with
HPLMN or EHPLMN required
0 0 no preference
Communicating the GAN PLMN Continuity Preference (GPCP) to
the Network
The MS can communicate its GAN PLMN Continuity
Preference to the GANC when attempting to register for GAN
Services.
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In some embodiments, the MS communicates its GAN
PLMN Continuity Preference to a GANC in, for example, an
uplink message. Examples of uplink messages where the GPCP
can be indicated include registration messages and post-
registration messages. A registration message is a message
sent by an MS when it first tries to register for GAN
services. A post-registration message is a message sent by
an MS after it has already registered for GAN services, for
example to perform status changes.
A specific example of a registration message is
the Registration Request (GA-RC REGISTER REQUEST) defined in
3GPP TS 44.318. A specific example of a post-registration
message is the Registration Update message (GA-RC REGISTER
UPDATE UPLINK message) defined in 3GPP TS 44.318. The
Registration Update message may be used for many reasons,
for instance if the MS acquires GERAN/UTRAN coverage for the
first time after reporting no coverage to the GANC during
the registration process. The full list of uses of this
message is given in 3GPP TS 44.318 Section 6.3.1. The GA-RC
REGISTER UPDATE UPLINK message is used from the MS to the
GANC, and it currently includes a Required GAN Services IE
(information element). Examples of post-registration
messages that might be used in dedicated mode include the
GA-CSR CLASSMARK CHANGE and the GA-CSR UTRAN CLASSMARK
CHANGE messages. The GANC initiates the classmark
interrogation procedure by transmitting the GA-CSR CLASSMARK
ENQUIRY message to the MS when it desires more information
about the MS capabilities. In the "early classmark sending"
case, if allowed, the GA-CSR (UTRAN) CLASSMARK CHANGE
message can be sent by the MS once it is in dedicated mode.
In some embodiments, these messages are enhanced to include
an additional field for the GPCP as illustrated in the table
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below for the case of the GA-CSR CLASSMARK CHANGE MESSAGE
(described in section 10.1.27 of 3GPP TS 44.318):
GA-CSR CLASSMARK CHANGE message content
IEI Information Type/ Presence Format Length Value Notes
Element Reference
Length Length M V 2
Indicator indicator
11.1.1.1
GA-CSR Protocol M V 1~ 0001
Protocol Discriminator
Discriminator 11.1.1.2
Skip Skip M V 1~ 0000
Indicator indicator
11.1.1.3
GA-CSR Message Type M V 1
CLASSMARK 11.1.1.4
CHANGE
message
identity
28 Mobile Mobile M TLV 5
Station Station
Classmark 2 Classmark 2
11.2.28
56 Additional Mobile C TLV 3-14
Mobile Station
Station Classmark 3
Classmark 11.2.56
Information
xxx GAN PLMN PLMN 0 TLV 3
Continuity Continuity
Preference Preference,
11.2.xxx
5 In some embodiments, when the MS prefers PLMN
Continuity but has not achieved this during the initial
registration, the GA-RC REGISTER UPDATE UPLINK message is
used to signal the GAN PLMN Continuity Preference of the MS
using a continuity request. Alternatively, the MS may use
10 this update procedure or the classmark change procedure to
signal a change in the GAN PLMN continuity preference, as
configured by a user of the device or an operator to name
two specific examples. This can be done by the addition of a
new dedicated information element, a "PLMN Continuity
15 Request", to these messages. Alternatively, the GAN PLMN
Continuity Preference Request may be signaled in the GA-RC
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REGISTER UPDATE UPLINK message by a new field that is added
to the existing Required GAN Services IE. Table 5 below
shows examples of both of these cases, namely a modified
Required GAN Services IE (see Information Element Identifier
(IEI) 71 in the table) that includes the PLMN Continuity
Preference, and a new IE referred to as "PLMN continuity
Request" (see IEI xxx in the table) that includes the PLMN
Continuity Preference. In some embodiments, only one of
these alternatives are implemented. In another embodiment,
both are implemented and either can be used in a given
instance. The GPCP format provided is a specific example;
other formats can alternatively be employed. The modified
Required GAN Services IE and a possible new IE is shown in
the modified GA-RC REGISTER UPDATE UPLINK message content
below.
Table 5: modified GA-RC REGISTER UPDATE UPLINK message
IEI Information Type/ Presence Format Length Value Notes
Element Reference
Length Length M V 2
Indicator indicator
11.1.1.1
GA-RC Protocol M V 1~ 0000
Protocol Discriminator
Discriminator 11.1.1.2
Skip Skip M V 1~ 0000
Indicator indicator
11.1.1.3
GA-RC Message Type M V 1
REGISTER 11.1.1.4
UPDATE
UPLINK
message
identity
3 AP Radio Iden Radio 0 TLV 9
Identity
11.2.3
6 Coverage GERAN/UTRAN 0 TLV 3
Indication Coverage
Indicator
11.2.6
4 GERAN Cell GERAN Cell C TLV 4
Identity Identity
11.2.4
5 Location Area Location Area C TLV 7
Identifi- Identification
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cation 11.2.5
41 Routing Area Routing Area C TLV 3
Code
11.2.41
8 Geographic Geographical 0 TLV 9-n
Location Location
11.2.8
42 AP Location AP Location 0 TLV 7-n
11.2.42
71 Required GAN Required GAN 0 TLV 3
Services Services
11.2.71
73 3G Cell 3G Cell C TLV 6
Identity Identity
11.2.73
61 AP Service AP Service C TLV 4-260
Name Name
11.2.61
82 3G UARFCN 3G UARFCN 0 TLV 4
11.2.82
xxx PLMN PLMN 0 TLV 3
Continuity Continuity
Request Request
11.2.xxx
Required GAN Services
As indicated above, in some embodiments, the
Required GAN services IE is modified to include GAN PLMN
continuity preference. The purpose of the (Required GAN
Services) IE is to indicate to the GANC that the MS requires
a GAN related specific service and which of the GAN services
the MS requires. Table 6 contains an example definition of
the Required GAN Services IE modified to include the GAN
PLMN continuity preference, as a two bit CR (continuity
request) in the table:
Table 6: Required GAN Services IE with CR
8 7 6 5 4 3 2 1
Required GAN Services IEI octet
1
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Length of Required GAN Services octet
contents 2
Spare CR CBS octet
3
where CR and CBS are defined in Table 7 below.
Table 7: CR and CBS definitions
CBS Cell Broadcast Service (octet 3)
Bit
1
0 CBS is not required by the mobile
station
1 CBS is required by the mobile
station.
CR Continuity Request (octet 3)
Bit
1 0
1 1 MS requires PLMN continuity
1 0 MS prefers PLMN continuity
0 1 GANC associated with HPLMN or
EHPLMN required
0 0 no preference
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PLMN Continuity Request
As indicated above, in some embodiments, a new
PLMN Continuity Request IE is used to signal the GAN PLMN
continuity preference. Table 8 below is an example
definition.
Table 8: PLMN Continuity Request IE
8 7 6 5 4 3 2 1
PLMN Continuity Request IEI octet
1
Length of PLMN Continuity Request octet
contents 2
Spare CR octet
3
where CR is defined in Table 9 below.
Table 9: CR Definition
CR Continuity Request (octet 3)
Bit
Bit
1 0
1 1 MS requires PLMN
continuity
1 0 MS prefers PLMN
continuity
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0 1 GANC Associated with
HPLMN or EHPLMN required
0 0 no preference
In some embodiments, the Required GAN Services IE
or the PLMN Continuity Request IE can also, or
alternatively, be sent with an initial registration request
5 message (GA-RC REGISTER REQUEST message). This can allow
the MS to inform the Default GANC on the first registration
attempt that it is looking for PLMN continuity. The GA-RC
REGISTER REQUEST message is shown in the following table,
with the modification to the Required GAN Services IE and
10 the addition of the new PLMN Continuity Request IE.
Table 10: GA-RC REGISTER REQUEST
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IEI Information Type/ Presence Format Length Value Notes
Element Reference
Length Length M V 2
Indicator indicator
11.1.1.1
GA-RC Protocol M V 1~ 0000
Protocol Discriminator
Discriminator 11.1.1.2
Skip Skip Indicator M V 1~ 0000
Indicator 11.1.1.3
GA-RC Message Type M V 1
REGISTER 11.1.1.4
REQUEST
message
identity
1 IMSI Mobile M TLV 10
Identity
11.2.1
2 GAN Release GAN Release M TLV 3
Indicator indicator
11.2.2
7 GAN Classmark GAN Classmark M TLV 4
11.2.7
3 AP Radio Radio Identity C TLV 9-n
Identity 11.2.3
96 MS Radio Radio Identity M TLV 9-n
identity 11.2.3
17 GSM RR/UTRAN GSM RR/ UTRAN M TLV 3
RRC State RRC State
11.2.17
6 Coverage GERAN/UTRAN M TLV 3
Indication coverage
Indicator
11.2.6
4 GERAN Cell GERAN Cell C TLV 4
Identity Identity
11.2.4
Location Area Location Area C TLV 7
Identificatio identification
n 11.2.5
41 Routing Area Routing Area C TLV 3
Code Code
11.2.41
8 Geographic Geographical 0 TLV 9-n
Location Location
11.2.8
42 AP location AP Location 0 TLV 7-n
11.2.42
21 Register Register C TLV 3
Reject Cause reject Cause
11.2.21
11 Redirection Redirection C TLV 3
Counter Counter
11.2.11
9 Last GANC- IP Address C TLV 7-19
SEGW IP 11.2.9
address
Last GANC- Fully C TLV 5-258
SEGW FQDN Qualified
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Domain/Host
Name
11.2.10
97 Last GANC IP IP Address C TLV 7-19
address 11.2.9
98 Last GANC Fully C TLV 5-258
FQDN Qualified
Domain/Host
Name
11.2.10
61 AP Service AP Service C TLV 4-260
Name Name
11.2.61
68 Registration Registration C TLV 3
indicators indicators
11.2.68
69 GAN PLMN List GAN PLMN List C TLV n
11.2.69
71 Required GAN Required GAN 0 TLV 3
Services Services
11.2.71
73 3G Cell 3G Cell C TLV 6
Identity Identity
11.2.73
82 3G UARFCN 3G UARFCN 0 TLV 4
11.2.82
74 3G Security 3G Security C TLV 6
Capability Capability
11.2.111
xxx PLMN PLMN 0 TLV 3
Continuity Continuity
Request Request
11.2.xxx
These information element fields may be defined, for example
as defined previously for the GA-RC REGISTER UPDATE Uplink
message.
Automatic Adjustment of GPCP While in Dedicated Mode
In some embodiments an option is provided whereby
anytime the MS is in dedicated mode (that is in an active
voice or data session) the GPCP is automatically configured
on the MS to'PLMN Continuity Required" for the duration of
the active session and then set back to the regular setting
when the active session ends. This change in PLMN
continuity requirement is communicated to the network, for
example, using the methods described herein. In some
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embodiments, the GPCP is automatically configured to'PLMN
Continuity Required" only in the case of a voice call and
not in the case of a data session. This captures the
assumption that users do not want a dropped voice call but
that interruptions in data services may be acceptable.
Network and Mobile Station Behaviour in Response to the GAN
PLMN Continuity Preference
Various approaches have been described above for
communicating GAN PLMN continuity preference information for
a MS from the MS to a GANC. Further embodiments relate to
the behavior of the GANC in response to such GAN PLMN
continuity preference information for cases where the GANC
is equipped to process the continuity preference
information. Yet further embodiments relate to the
behaviour of the MS based on the GAN PLMN continuity
preference information. Some embodiments involve new
behaviour in the network; some embodiments involve new
behaviour in the MS; some embodiments involve new behaviour
in both the MS and the network. Note that some of these
embodiments are described in concert with the transmission
of GAN PLMN Continuity Preference information.
In some cases, the RPLMN that the MS is currently
registered with in cellular is available via one or more
GANC5 and/or an EPLMN is available via one or more GANC5,
and embodiments are provided to deal with this. In some
cases, the RPLMN that the MS is currently registered with in
cellular is not available via any GANC, and no EPLMN is
available, and embodiments are provided to deal with this.
These embodiments can be independently implemented. Some
implementations feature a combination of two or more
embodiments to address both scenario types.
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Two broad categories of behaviour are described
below. The first category involves behaviour when the
cellular RPLMN and/or EPLMN is available via one or more
GANC5. The second category of behaviour is when the
cellular RPLMN is not available via one or more GANC5, and
no EPLMN is available via one or more GANC5.
Behaviour When the Cellular RPLMN or EPLMN is available via
one or more GANCs
When the RPLMN or an EPLMN is available via one or
more of the GANC5, a PLMN mismatch can still occur. For
example, if the Default GANC (the Default GANC is by
definition associated with the HPLMN or EHPLMN) accepts the
registration of the MS even though the RPLMN is not the
HPLMN or an EHPLMN, there will be a mismatch. A PLMN
mismatch may also occur if the Default GANC redirects the MS
to an alternate GANC that is not associated with the RPLMN
or an EPLMN. A PLMN mismatch may also occur if the Default
GANC redirects the MS by providing the GAN PLMN list, where
the GAN PLMN list does not contain the RPLMN or an EPLMN.
Two categories of behaviour will be described. In
the first, the MS is registered in the cellular network on a
RPLMN which is not the HPLMN or an EHPLMN. In the second,
the MS is registered in the cellular network on the HPLMN or
an EHPLMN. Behaviours are described both for the case where
the Default GANC is configured to process the GAN PLMN
continuity preference, and the case where the Default GANC
is a legacy GANC.
1) The MS is registered in the cellular network on a RPLMN
which is not the HPLMN or an EHPLMN (e.g. a VPLMN (Visited
PLMN))
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When the MS sends a GA-RC REGISTRATION REQUEST
message to the Default GAN, it will include the indication
of its GAN PLMN Continuity Preference as described above.
If the Default GANC supports the PLMN Continuity Request
5 then behaviour is a function of the continuity request as
follows:
a. If there is a single available GANC that is
associated with the RPLMN of the MS or an equivalent PLMN to
the RPLMN of the MS, and the continuity preference is
10 required or preferred, the Default GANC will redirect the MS
to that specific GANC using the existing GA-
RC REGISTER REDIRECT message. This may, for example, be
achieved by including a PLMN Mobile Country Code (MCC) and
PLMN Mobile Network Code (MNC) of the RPLMN or an equivalent
15 PLMN to the RPLMN in an RC REGISTER REDIRECT message.
b. If there is more than one available GANC
associated with the RPLMN of the MS and/or one or more
available equivalent PLMN to the RPLMN of the MS, and the
continuity preference is required or preferred, the Default
20 GANC will send the MS a GA-RC REGISTER REDIRECT message with
the GAN PLMN list included, and the GAN PLMN list will
contain the GANC-PLMN pairs where the PLMN is the RPLMN or
an equivalent PLMN(s). The MS can then proceed to register
with a GANC of its choice from the list.
25 c. If the continuity preference is GANC associated
with HPLMN or EHPLMN required, then the Default GANC will
accept the registration.
d. If the continuity preference is no preference,
then the Default GANC may accept, reject, or redirect the
30 MS, for example as currently described in 3GPP TS 44.318.
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If the Default GANC does not support the PLMN
Continuity Request (i.e. if it a legacy GANC), then it may
do one of three things which are subject to different MS
behaviour depending on the GPCP:
a. The Default GANC may accept the registration
request message from the MS, even though there is a PLMN
mismatch. In this case the MS may exhibit different
behaviours depending on its GPCP field.
i. If the MS requires PLMN Continuity
and it receives a GA-RC REGISTER ACCEPT message from the
Default GANC when the RPLMN is not the HPLMN and is not an
EHPLMN, then the MS will ask the Default GANC to send the
GAN PLMN list; note at this point, the MS does not know that
the desired PLMN will be on the list, but the category of
behaviour being described here is for "Behaviour When the
Cellular RPLMN or an equivalent PLMN to the Cellular RPLMN
is available via one or more GANC5". Once the MS has the
list, the MS de-registers from default GANC, and attempts
registration with a GANC associated with a PLMN that is the
same or equivalent to the Cellular RPLMN.
ii. If the MS prefers PLMN Continuity
and it receives a GA-RC REGISTER ACCEPT message from the
Default GANC when the RPLMN is not the HPLMN and is not an
EHPLMN, then the MS will again ask the Default GANC to send
the GAN PLMN list; note at this point, the MS does not know
that the desired PLMN will be on the list, but the category
of behaviour being described here is for "Behaviour When the
Cellular RPLMN or ERPLMN is available via one or more
GANC5". Once the MS has the GAN PLMN list, it de-registers
with the Default GANC and attempts registration with a GANC
that is associated with a PLMN that is the same or
equivalent to the cellular RPLMN.
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iii. If the MS requires the GANC to be
associated with HPLMN, then, since the Default GANC is
associated with the HPLMN or EHPLMN, the MS will receive GAN
services over the Default GANC or other GANC associated with
the HPLMN or EHPLMN.
iv. If the MS has no preference, then
the MS will receive GAN services over the Default GANC.
b. The Default GANC may reject the registration
request message from the MS. In this case the MS will
follow the existing behaviour for Registration Rejected as
defined in 3GPP TS 44.318 Section 6.2.3.3.
c. The Default GANC may redirect the MS to another
GANC. The RPLMN may or may not be associated with the GANC
that the MS is redirected to. The MS behaviour will depend
on the GPCP:
i. If the MS requires or prefers PLMN
continuity, and the redirect PLMN matches the cellular RPLMN
either because the RPLMN or an equivalent PLMN to the
cellular RPLMN is associated with the redirected GANC, the
MS goes ahead and initiates registration with the redirect
GANC and its associated PLMN. If the PLMN associated with
the redirect GANC does not match the cellular RPLMN or an
equivalent PLMN to the cellular RPLMN, then rather than
initiating registration towards the GANC received in the
redirect message the MS triggers the Default GANC to send
the GAN PLMN list. The MS then initiates registration
towards a GANC on the GAN PLMN list that is associated with
the cellular RPLMN or with an equivalent PLMN to the
cellular RPLMN.
ii. If the MS requires that the GANC be
associated with the HPLMN or EHPLMN, then the MS again
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initiates registration to the Default GANC. If the Default
GANC rejects or redirects the MS again, then rove-in or
handover in to GAN is not successful. The MS may re-
initiate the discovery procedure as defined in 3GPP TS
44.318 Section 5.
iii. If the MS has no preference it will
initiate registration towards the GANC received in the
redirect message.
d. The Default GANC may redirect the MS to another
GANC using the GAN PLMN list. The assumption is that the
RPLMN or one or more equivalent PLMN5 to the RPLMN will be
on the GAN PLMN list since the behaviour being described
here is for the general category "Behaviour When the
Cellular RPLMN or a PLMN equivalent to the RPLMN is
available via one or more GANC5". The MS behaviour will
depend on the GPCP:
i. If the MS requires or prefers PLMN
continuity it will initiate registration towards a GANC on
the GAN PLMN list associated with the cellular RPLMN or with
a PLMN equivalent to the cellular RPLMN.
ii. If the MS requires the GANC be
associated with the HPLMN or EHPLMN, then the MS will try
instead to register again with the Default GANC. If the
Default GANC rejects or redirects the MS again, then rove-in
or handover in to GAN is not successful. The MS may re-
initiate the discovery procedure as defined in 3GPP TS
44.318 Section 5.3.
iii. If the MS has no preference it will
initiate registration towards any of the GANC received in
the GAN PLMN list.
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2) The MS is registered in the cellular network on the
HPLMN or an EHPLMN
When the MS sends a GA-RC REGISTRATION REQUEST
message to the Default GAN, it will include the indication
of its GAN PLMN Continuity Preference as described above.
If the Default GANC supports the PLMN Continuity Request it
will behave depending on the MS GPCP field:
a. If the MS preference is PLMN Continuity
Required or PLMN Continuity Preferred, or GANC associated
with HPLMN or EHPLMN required, then the Default GANC accepts
the registration request from the MS.
b. If the MS has no preference, then the Default
GANC may accept, reject, or redirect the MS, for example as
currently described in 3GPP TS 44.318.
If the Default GANC does not support the PLMN
Continuity Request (i.e. if it a legacy GANC), then it may
do one of four things which are subject to different MS
behaviour depending on the GPCP:
a. The Default GANC may accept the registration
request of the MS. Then the MS will receive GAN services
over the Default GANC, which is the preferred scenario
regardless of the setting of the GPCP.
b. The Default GANC may reject the registration
request of the MS. In this case the MS can behave as set
forth in 3GPP TS 44.318 Section 6.2.3.3.
c. The Default GANC may redirect the MS to another
GANC, for example with a REGISTER REDIRECT message
containing a single GANC target. The RPLMN (which is the
HPLMN or an EHPLMN in this case) may or may not be
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associated with the GANC that the MS is redirected to. The
MS behaviour will depend on the GPCP:
i. If the MS requires or prefers PLMN
continuity, or if the MS requires that the GANC be
5 associated with the HPLMN or EHPLMN, and the PLMN associated
with the redirect GANC is the HPLMN or an EHPLMN), then the
MS initiates registration with the redirect GANC. If the
redirect GANC is associated with a different PLMN (VPLMN)
that is not the HPLMN or an EHPLMN, then rather than
10 initiating registration towards the redirect GANC, the MS
triggers the Default GANC to send the GAN PLMN list. The MS
then initiates registration towards a GANC on the GAN PLMN
list associated with the HPLMN or an EHPLMN. If the Default
GANC rejects or directs the MS again, then rove-in or
15 handover in to GAN is not successful. The MS may re-
initiate the discovery procedure as defined in 3GPP TS
44.318 Section 5.
ii. If the MS has no preference it will
initiate registration towards the GANC received in the
20 redirect message.
d. The Default GANC may redirect the MS to another
GANC using the GAN PLMN list. The assumption is that the
RPLMN (the HPLMN or an EHPLMN in this case) will be on the
GAN PLMN list since the behaviour being described here is
25 for the general category "Behaviour When the Cellular RPLMN
or a PLMN equivalent to the RPLMN is available via one or
more GANC5". The MS behaviour will depend on the GPCP:
i. If the MS requires or prefers PLMN
continuity or if the MS requires that the GANC be associated
30 with the HPLMN, then it will initiate registration towards a
GANC on the GAN PLMN list associated with the HPLMN or an
EHPLMN.
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ii. If the MS has no preference it will
initiate registration towards any of the GANCs received in
the GAN PLMN list.
Behaviour When Neither the Cellular RPLMN nor an equivalent
PLMN to the cellular PLMN is available via one or more GANC5
When the MS sends a GA-RC REGISTRATION REQUEST
message to the Default GANC, it will include the indication
of its GAN PLMN Continuity Preference as described above.
If the Default GANC supports the PLMN Continuity Request,
behaviour of the Default GANC will be dependent on the GAN
PLMN Continuity Preference:
i) if the continuity preference is required, it
will reject the registration, but send the MS a GAN PLMN
list so that the MS can attempt to register with a different
Cellular PLMN for which there is an associated GANC as
described below.
ii) if the continuity preference is preferred, it
will reject the registration, but send the MS a GAN PLMN
list so that the MS can attempt to register with a different
Cellular PLMN for which there is an associated GANC as
described below. Eventually, if a cellular PLMN with an
associated GANC is not found, the MS may proceed with
registering with a GANC to obtain GAN services even though
the PLMN associated with the registered GANC does not match
or is not equivalent to the cellular RPLMN.
iii) if the continuity preference is GANC
associated with HPLMN or EHPLMN required, the Default GANC
will accept the registration;
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iv) if the continuity preference is no preference,
the Default GANC may accept the registration or redirect the
MS to a different GANC.
If the Default GANC does not support the PLMN
Continuity Request (i.e. if it a legacy GANC), then the
Default GANC may do one of four things which are subject to
different MS behaviour depending on the GPCP:
a. The Default GANC may accept the registration
request message from the MS, even though there is a PLMN
mismatch. In this case the MS may exhibit different
behaviours depending on its GPCP field.
i. If the MS Requires PLMN Continuity
and it receives a GA-RC REGISTER ACCEPT message from the
Default GANC when the RPLMN is not the HPLMN and is not an
EHPLMN, then the MS will trigger the Default GANC to send
the GAN PLMN list; note at this point, the MS does not know
that the desired PLMN is not on the list, but the category
of behaviour being described here is for "Behaviour When
Neither the Cellular RPLMN nor an equivalent PLMN is
available via one or more GANC5". Once the MS has the list,
the MS becomes aware that it is not able to register with a
GANC associated with the Cellular RPLMN or or an equivalent
PLMN. It then attempts to register with a cellular PLMN that
allows for a PLMN match to be achieved, as described below.
If attempts to register with a cellular PLMN that allows for
a PLMN match is not achieved, then rove-in or handover in to
GAN has failed. The MS may re-initiate the discovery
procedure as defined in 3GPP TS 44.318 Section 5.
ii. If the MS Prefers PLMN Continuity
and it receives a GA-RC REGISTER ACCEPT message from the
Default GANC when the RPLMN is not the HPLMN or an EHPLMN,
then the MS will trigger the Default GANC to send the GAN
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PLMN list; note at this point, the MS does not know that the
desired PLMN will not be on the list, but the category of
behaviour being described here is for "Behaviour When
Neither the Cellular RPLMN nor an equivalent PLMN is
available via one or more GANC5". Once the MS has the GAN
PLMN list, the MS becomes aware that it is not able to
register with a GANC associated with the Cellular RPLMN or
an equivalent PLMN. It then attempts to register with a
cellular PLMN that allows for a PLMN match to be achieved,
as described below. If attempts to register with a cellular
PLMN to achieve a PLMN match with a PLMN associated with an
available GANC fail, the MS may proceed with accepting GAN
services through a GANC for which there is no PLMN match.
iii. If the MS requires the GANC to be
associated with HPLMN or an EHPLMN, then the MS will receive
GAN services over the Default GANC.
iv. If the MS has no preference, then
the MS will receive GAN services over the Default GANC.
b. The Default GANC may reject the registration
request message from the MS. In this case the MS will
follow the existing behaviour for Registration Rejected as
defined in 3GPP TS 44.318 Section 6.2.3.3.
c. The Default GANC may redirect the MS to another
GANC using a registration redirect message. The MS
behaviour will depend on the GPCP:
i. The PLMN associated with the redirect
GANC does not match the cellular RPLMN or a PLMN equivalent
to the cellular RPLMN, and as such, if the MS requires PLMN
continuity, then rather than initiating registration towards
the GANC received in the redirect message the MS triggers
the Default GANC to send the GAN PLMN list. The MS then
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attempts to register with a different Cellular PLMN that
allows for a PLMN match to be achieved, as detailed below.
If attempts to register with a cellular PLMN that allows for
a PLMN match is not achieved, then rove-in or handover in to
GAN has failed. The MS may re-initiate the discovery
procedure as defined in 3GPP TS 44.318 Section 5.
ii. If the MS prefers PLMN continuity,
the MS triggers the Default GANC to send the GAN PLMN list.
The MS then attempts to register with a different Cellular
PLMN that allows for a PLMN match to be achieved, as
detailed below. If the MS is unable to register with a
different cellular PLMN such that a PLMN match may be
achieved, then the MS may proceed with accepting GAN
services through the redirect GANC even though there is no
PLMN match.
iii. If the MS requires that the GANC be
associated with the HPLMN or EHPLMN, then the MS re-attempts
registration with the Default GANC. If the Default GANC
rejects or redirects the MS again, then rove-in or handover
in to GAN is not successful. The MS may re-initiate the
discovery procedure as defined in 3GPP TS 44.318 Section 5.
iv. If the MS has no preference it will
initiate registration towards the GANC received in the
redirect message.
d. The Default GANC may redirect the MS to another
GANC using the GAN PLMN list. The assumption is that the
Cellular RPLMN will not be on the GAN PLMN list since the
behaviour being described here is for the general category
"Behaviour When Neither the Cellular RPLMN nor an equivalent
PLMN is available via one or more GANC5". The MS behaviour
will depend on the GPCP:
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i. If the MS requires PLMN continuity,
it will attempt to register with a different Cellular PLMN
that allows for a PLMN match to be achieved, as detailed
below. If attempts to register with a cellular PLMN that
5 allows for a PLMN match is not achieved, then rove-in or
handover in to GAN has failed. The MS may re-initiate the
discovery procedure as defined in 3GPP TS 44.318 Section 5.
ii. If the MS prefers PLMN continuity,
it will attempt to register with a different Cellular PLMN
10 that allows for a PLMN match to be achieved, as detailed
below. If attempts to register with a cellular PLMN to
achieve a PLMN match with GANC fail, the MS may proceed with
accepting GAN services through a GANC for which there is no
PLMN match.
15 iii. If the MS requires that the GANC be
associated with the HPLMN or EHPLMN, then the MS re-attempts
registration with the Default GANC. If attempts to register
with a cellular PLMN that allows for a PLMN match is not
achieved, then rove-in or handover in to GAN has failed.
20 The MS may re-initiate the discovery procedure as defined in
3GPP TS 44.318 Section 5.
iv. If the MS has no preference it will
initiate registration towards any of the GANC received in
the GAN PLMN list.
25 Further Embodiments
Figure 2 is a flowchart of a method executed by a
MS. The method involves, at block 2-1, a MS transmitting a
communication that indicates a preference for the MS in
respect of PLMN continuity when roving into or out of GAN or
30 handing over into or out of GAN. In some embodiments, the
information indicates a preference for PLMN continuity from
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a set of possible preferences, the set comprising at least
two of, or all of: PLMN continuity required; PLMN continuity
preferred; GANC associated with HPLMN or an EHPLMN required;
No preference.
Figure 3 is a flowchart of a method executed by a
GANC. The method involves, at block 3-1, receiving
signalling information that indicates a preference for a MS
in respect of PLMN continuity when roving into or out of GAN
or handing over into or out of GAN.
Figure 4 is a flowchart of another method executed
by a MS. The method involves, at block 4-1, transmitting a
registration request for GAN to a default GANC. At block 4-
2, the MS receives a response to the registration request.
At block 4-3, the MS handles the response based on a PLMN
continuity preference for the MS.
In some embodiments, receiving a response to the
registration request comprises receiving an acceptance of
the registration request by a GANC that is not associated
with the cellular PLMN, and wherein handling the response
based on the PLMN continuity preference for the MS comprises
at least one of:
for a continuity preference of PLMN continuity
required:
a) requesting a GAN PLMN list;
b) attempting to register with another GANC on the
GAN PLMN list that is associated with a PLMN matching or
equivalent to the cellular PLMN.
for a continuity preference of PLMN continuity
preferred:
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a) requesting a GAN PLMN list;
b) attempting to register with another GANC on the
GAN PLMN list that is associated with a PLMN matching or
equivalent to the cellular PLMN, and ultimately if a PLMN
match is not achieved accepting GAN services through a GANC
for which there is no PLMN match.
for a continuity preference of GANC associated
with HPLMN or EHPLMN required:
a) receiving GAN services through the GANC if the
GANC is associated with the HPLMN or EHPLMN;
b) if the GANC is not associated with the HPLMN or
an EHPLMN, attempting to register with a GANC associated
with the HPLMN or an EHPLMN;
for a continuity preference of no preference:
a) receiving GAN services through the GANC.
In some embodiments, receiving a response to the
registration request comprises receiving a registration
redirect to a single GANC that is associated with the
cellular PLMN, and wherein handling the response based on
the PLMN continuity preference for the MS comprises at least
one of:
for a continuity preference of PLMN continuity
required:
a) registering with the single GANC and receiving
GAN services through the single GANC;
for a continuity preference of PLMN continuity
preferred:
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a) registering with the single GANC and receiving
GAN services through the single GANC;
for a continuity preference of GANC associated
with HPLMN or EHPLMN required:
a) registering with the single GANC and receiving
GAN services through the single GANC if the GANC is
associated with the HPLMN or an EHPLMN;
b) if the single GANC is not associated with the
HPLMN or an EHPLMN, attempting to register with a GANC
associated with the HPLMN or an EHPLMN;
for a continuity preference of no preference:
a) registering with the single GANC and receiving
GAN services through the GANC.
In some embodiments, receiving a response to the
registration request comprises receiving a registration
redirect to a single GANC that is not associated with the
cellular RPLMN or a PLMN equivalent to the cellular PLMN.
In this case, handling the response based on the
PLMN continuity preference for the MS comprises at least one
of:
for a continuity preference of PLMN continuity
required:
a) requesting a GAN PLMN list;
b) attempting to register with another GANC on the
GAN PLMN list that is associated with the RPLMN or a PLMN
equivalent to the cellular PLMN;
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for a continuity preference of PLMN continuity
preferred:
a) requesting a GAN PLMN list;
b) attempting to register with another GANC on the
GAN PLMN list that is associated with a PLMN matching the
RPLMN or a PLMN equivalent to the cellular PLMN, and
ultimately if a PLMN match is not achieved accepting GAN
services through a GANC for which there is no PLMN match.
for a continuity preference of GANC associated
with HPLMN or EHPLMN required:
a) if the single GANC is associated with the HPLMN
or an EHPLMN, registering with the single GANC;
b) if the single GANC is not associated with the
HPLMN or an EHPLMN, requesting the GAN PLMN list and
attempting to register with a GANC associated with the HPLMN
or an EHPLMN;
for a continuity preference of no preference:
a) registering with the single GANC.
In some embodiments, receiving a response to the
registration request comprises receiving a GAN PLMN list
containing at least one GANC that is associated with the
RPLMN or a PLMN equivalent to the cellular PLMN, and wherein
handling the response based on the PLMN continuity
preference for the MS comprises at least one of:
for a continuity preference of PLMN continuity
required:
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a) registering with a GANC on the GAN PLMN list
associated with the RPLMN or a PLMN equivalent to the
cellular PLMN and receiving GAN services through that GANC;
for a continuity preference of PLMN continuity
5 preferred:
a) registering with a GANC on the GAN PLMN list
associated with the RPLMN or a PLMN equivalent to the
cellular PLMN and receiving GAN services through that GANC
for a continuity preference of GANC associated
10 with HPLMN or EHPLMN required:
attempting to register with a GANC that is
associated with the HPLMN or an EHPLMN;
for a continuity preference of no preference:
a) registering with a GANC on the GAN PLMN list
15 and receiving GAN services through the GANC.
In some embodiments, receiving a response to the
registration request comprises receiving a GAN PLMN list
containing no GANC that is associated with the RPLMN or a
PLMN equivalent to the cellular PLMN, and wherein handling
20 the response based on the PLMN continuity preference for the
MS comprises at least one of:
for a continuity preference of PLMN continuity
required:
a) attempting to register with a different
25 cellular PLMN for which a PLMN match can be achieved as
determined from the GAN PLMN list, where such a PLMN match
is possible;
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b) if successful, registering with a GANC
associated with the different cellular PLMN or a PLMN
equivalent to the different cellular PLMN;
for a continuity preference of PLMN continuity
preferred:
a) attempting to register with a different
cellular PLMN for which a PLMN match can be achieved as
determined from the GAN PLMN list, where such a PLMN match
is possible, and registering with a GANC associated with the
different cellular PLMN;
b) where no PLMN match is possible by changing the
registered cellular PLMN, registering with a GANC for which
there is no PLMN match;
for a continuity preference of GANC associated
with HPLMN or EHPLMN required:
attempting to register with the GANC is associated
with the HPLMN or an EHPLMN; If the MS is not registered
with the HPLM or EHPLMN in cellular, the MS goes back to the
cellular network and tries to register on the HPLMN or an
EHPLMN.
for a continuity preference of no preference:
a) registering with one of the GANC on the GAN
PLMN list.
Figure 5 is a flowchart for execution by a GANC.
The method involves, at block 5-1, receiving a registration
request containing a PLMN continuity preference. In block
5-2, the GANC, as a function of the PLMN continuity
preference, selects between a) accepting the registration
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request b) performing a registration redirect, and
c)rejecting the registration request.
In some embodiments, as a function of the PLMN
continuity preference, selecting between a) accepting the
registration request b) performing a registration redirect
and c) rejecting the registration request comprises, for a
PLMN continuity preference of PLMN continuity required:
accepting the registration if the GANC is
associated with a PLMN matching a current RPLMN or a PLMN
equivalent to the cellular PLMN;
if the GANC is not associated with a PLMN matching
the RPLMN or a PLMN equivalent to the cellular PLMN,
performing at least one of:
a) redirecting to a GANC associated with a PLMN
matching the current RPLMN or a PLMN equivalent to the
cellular PLMN;
b) sending a GAN PLMN list containing at least one
GANC associated with the RPLMN or a PLMN equivalent to the
cellular PLMN;
c) sending a GAN PLMN list so as to allow the MS
to perform cellular PLMN re-selection.
In some embodiments, as a function of the PLMN
continuity preference, selecting between a) accepting the
registration request and b) performing a registration
redirect and c) rejecting the registration request
comprises, for a PLMN continuity preference of PLMN
continuity preferred:
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accepting the registration if the GANC is
associated with a PLMN matching a current RPLMN or a PLMN
equivalent to the cellular PLMN;
if the GANC is not associated with a PLMN matching
the RPLMN or a PLMN equivalent to the cellular PLMN
performing at least one of:
a) redirecting to a GANC associated with a PLMN
matching the RPLMN or a PLMN equivalent to the cellular
PLMN;
b) sending a GAN PLMN list containing at least one
GANC associated with the RPLMN or a PLMN equivalent to the
cellular PLMN;
c) sending a GAN PLMN list so as to allow the MS
to perform cellular PLMN re-selection in order to achieve a
match;
d) accepting the registration despite a resulting
PLMN mismatch.
In some embodiments, as a function of the PLMN
continuity preference, selecting between a) accepting the
registration request and b) performing a registration
redirect and c) rejecting the registration request
comprises, for a PLMN continuity preference of GANC
associated with HPLMN or EHPLMN required:
a) accepting the registration if the GANC is a
default GANC associated with the HPLMN or
EHPLMN;
b) Redirecting to a GANC associated with the HPLMN
or EHPLMN;
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c) sending a GAN PLMN list so as to allow the MS
to select a GANC that is associated with the
HPLMN or an EHPLMN
Continuity Support Indication
In the embodiments described above, there is not
necessarily any explicit signalling that indicates that a
GANC has understood the PLMN Continuity Request field
(whether in a new IE or included as part of the GAN Required
Services IE). Therefore if the GANC does not seem to behave
according to the transmitted continuity request, the MS may
not know if this is because the GANC did not recognize it
(i.e. in the case of a legacy GANC that does not support
this message) or if it is because the RPLMN (cellular) is
not available via GAN.
In another embodiment, explicit signalling that
indicates that a GANC understands the PLMN continuity
request field is transmitted. Of course, only a GANC that
actually understands the field will be able to transmit the
explicit signalling. The signalling might, for example, be
part of the GA-RC REGISTER ACCEPT, REJECT, and/or REDIRECT
messages.
The table below provides an example of how the
support indication might be included within the accept
message by way of example (excerpt from 3GPP TS 44.318 with
amendment for support indication). Specifically, the
definition of the GA-RC Register Accept message content is
amended to include a PLMN Continuity Request support
indicator IE. The GANC provides system information to the
MS using this message. The contents of this message are a
collection of IEs from system information 3 and 13 of GERAN
specifications plus some additions and is transmitted from
GANC to MS.
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Table: GA-RC REGISTER ACCEPT message content
IEI Information Type/ Presence Format Length Value Notes
Element Reference
Length Length M V 2
Indicator indicator
11.1.1.1
GA-RC Protocol Protocol M V 1~ 0000
Discriminator Discriminator
11.1.1.2
Skip Indicator Skip Indicator M V 1~ 0000
11.1.1.3
GA-RC REGISTER Message Type M V 1
ACCEPT message 11.1.1.4
identity
4 Cell Identity Cell Identity M TLV 4
11.2.4
5 Location Area Location Area M TLV 7
Identification identification
11.2.5
14 GANC Control GAN Control M TLV 8
Channel Channel
Description Description
11.2.14
23 TU3910 Timer TU3910 Timer M TLV 4
11.2.23
22 TU3906 Timer TU3906 Timer M TLV 4
11.2.22
19 GAN Band GAN Band M TLV 3
11.2.19
37 TU3920 Timer TU3920 Timer M TLV 4
11.2.37
13 GANC Cell GAN Cell 0 TLV 4
Description Description
11.2.13
43 TU4001 Timer TU4001 Timer C TLV 4
11.2.43
TU4003 Timer TU4003 Timer C TLV 4
11.2.60
44 Location Location 0 TLV 3
Status Status
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11.2.44
62 GAN Service GAN Service 0 TLV 5-36
Zone Zone
Information information
11.2.62
67 Serving GANC Serving GANC 0 TLV 3
table table
indicator indicator
11.2.67
112 TU4004 Timer TU4004 Timer C TLV 3
11.2.78
xxx PLMN PLMN CR 0 TLV 3
Continuity support
Request indicator
support 11.2.xxx
indicator
The PLMN Continuity Request support indicator IE can, for
example, be defined as in the table below. This information
element is used to indicate whether of not the GANC supports
the PLMN Continuity Request signaling from the MS.
Table: PLMN CR support indicator
8 7 6 5 4 3 2 1
PLMN Continuity Request Support octet
Indicator IEI 1
Length of PLMN Continuity Request octet
Support Indicator IE contents 2
Spare CRSI octet
3
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In the above, the CRSI field might, for example, be defined
as in the table below.
CRSI, Continuity Request
Support Indicator (octet 3)
Bits
3 2 1
0 0 1 Continuity Request
Received and
Acknowledged
Continuity Request
Received and Ignored
Other fields for future
use
Switching Cellular RPLMN to achieve PLMN Match
As described above, there are various
circumstances where the MS becomes aware that the RPLMN or a
PLMN equivalent to the cellular PLMN is not available via
one or more GANC5. In some embodiments the MS initiates a
switch in the Cellular RPLMN to one that allows for a PLMN
match to be achieved. The MS behaviour will depend on the
GPCP.
a. If the MS requires PLMN continuity, then the MS
will go back to the cellular network and try to register on
another PLMN. It will do this using knowledge of the PLMN5
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available via GAN that it has obtained from the GAN PLMN
list. If the MS is unable to register on a PLMN in cellular
which is also available via GAN, then the MS rove-in or
handover in to GAN is unsuccessful.
b. If the MS prefers PLMN continuity, the MS will
go back to the cellular network and try to register on
another PLMN. It will do this using knowledge of the PLMN5
available via GAN that it has obtained from the GAN PLMN
list. If the MS is unable to register on a PLMN in cellular
that is also available via GAN, then the MS will select a
GANC-PLMN pair from the GAN PLMN list according to the
procedures defined in 3GPP TS 43.318 and TS 44.318. The MS
may, for example, change its continuity preference in the
registration message to achieve this.
c. If the MS requires the GANC be associated with
the HPLMN or an EHPLMN, then the MS will try to re-select to
the HPLMN or an EHPLMN in cellular. If it is unable to do
so then the MS rove-in or handover in to GAN is
unsuccessful.
d. If the MS has no preference, then the MS need
not be concerned that the RPLMN is not associated with any
GANC.
A method of achieving PLMN continuity for this
case will now be described with reference to Figure 6. In
block 6-1 the MS makes a network list consisting of the
PLMN5 that are available via GAN (i.e. those that were
received in the GAN PLMN list.). In block 6-2, the MS makes
a list of available PLMN5 for cellular. In block 6-3, the
MS compares the network list from GAN with the list of
available PLMN5 for cellular. In block 6-4, the MS
determines a PLMN that is available (i.e. common) via both
GAN and cellular, or determining a PLMN available in
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cellular for which there is an EPLMN available in GAN. In
block 6-5, the MS attempts to perform cellular and GAN
registration with a PLMN, GANC and a combination thus
determined. In some embodiments, this involves sorting the
list of common networks according to the prioritization for
automatic network selection (i.e. the EFOPLMNWACT), and trying
to register with the highest priority PLMN that is on the
list of common networks (via LAU, RAU, TAU or another
mechanism as appropriate). If this registration fails, then
the MS attempts to register on the next highest priority
PLMN in the list of common networks, and continues until
successful or all the common networks have been tried. If
the process is successful, then using the GAN PLMN list sent
from the Default GANC, the MS attempts to register on a GANC
that is associated with the new cellular PLMN. If the
process is unsuccessful, then there is no PLMN that can be
found that is common to both cellular and GAN. The MS may,
for example, continue GANC selection as per 3GPP TS 44.318.
In some embodiments, the network selection process
may, for example, be driven by an operator's preferred PLMN
list for cellular network selection, for example the
contents of an Elementary File (EF) containing an operator's
preferred PLMN list. This file is the EFOPLMNWACT (see 3GPP TS
31.102 section 4.2.53) and it is stored on the USIM. The
order of the contents of this list is typically used to
determine the selection of the PLMN. In some embodiments,
if an operator is seeking to ensure PLMN continuity with
GAN, then they provision the preferred PLMN list, for
example the EFOPLMNWACT list, such that networks which also
support GAN are prioritized, for example above those that do
not support GAN. The preferred PLMN list is sorted by the
operator and stored on the mobile device either during
device provisioning, or through over the air provisioning,
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or may be communicated to the MS using other methods. In
some embodiments, PLMN list prioritized according to GAN
support is further sorted in conjunction with other
prioritization preferences, such as but not limited to the
5 networks for roaming that are best suited to voice.
If however the MS utilizes the PLMN continuity
preference indication, and it is set to indicate "required"
or "preferred", then the MS may be permitted to only
consider the subset of the EFOPLMNWACT that contains the
10 networks that support GAN, which it is aware of from the GAN
PLMN List which has be received from the Default GANC.
Therefore once the MS detects that its cellular
PLMN is not in the GAN PLMN list and no equivalent PLMN is
on the list, the MS attempts to select a different PLMN in
15 cellular using the PLMN5 from the GAN PLMN list as the list
of PLMN5 sent to the NAS function as part of the PLMN
selection process. Trying to re-select the PLMN in cellular
before registering on the GAN will ensure that every
possible attempt is made to align the PLMN5. It may happen
20 that it is not possible to re-select a PLMN in cellular that
is part of the GAN PLMN list (due to operator policies,
unavailability, etc.). In this case the MS may stay
registered on the current RPLMN and go back to the GANC
Selection Process to choose a GANC-PLMN pair from the list
25 sent by the Default GANC.
The above-describe embodiment is also applicable
for maintaining PLMN continuity between a first network type
and a second network type. The corresponding method
involves making a network list consisting of the PLMN5 that
30 are available via a second network type by looking at
available PLMN5 in conjunction with a previously received
PLMN list; making a list of available PLMN5 for a first
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network type; comparing the network list to a list of
available PLMN5 for the first network type; determining a
common PLMN that is available via both the first network
type and the second network type or determining a PLMN
available in the first network type for which there is an
EPLMN available in the second network type; attempting to
perform registration in the first network type and the
second network type with the common PLMN, or the PLMN,
equivalent PLMN combination thus determined.
Network Prioritization by Operator
The above-described embodiment provided details of
network priorization by the operator, in the context of the
use of the GPCP. More generally, an embodiment of the
application provides for network prioritization so as to
enhance the likelihood of achieving PLMN continuity, without
necessarily also using the GPCP.
More generally, in some embodiments the network
transmits, and the MS receives, information from the network
containing network prioritization information, the
prioritization information prioritizing networks such that
networks for which PLMN continuity is possible are
prioritized above networks for which PLMN continuity is not
possible.
An embodiment related to this provides a network
node comprising a transmitter, and a network determiner
configured to determine a PLMN list of networks of a first
network type such that a PLMN on the list that also supports
a second network type is prioritized and to cause the
transmitter to transmit a configuration of the PLMN list to
a MS (mobile station).
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Network Prioritization by User/Mobile Station
The above-described embodiment involves the
network determining a PLMN list for increased likelihood of
PLMN continuity. This can be referred to as "operator
controlled PLMN selection". In another embodiment user
controlled PLMN selection is provided. In this embodiment,
a user preferred PLMN list, for example stored as an EF in
memory on the MS, is employed to similar effect. The user
defined list is updated by the MS as the MS learns which
PLMNS are supported via GAN, i.e. upon receiving the GAN
PLMN list. This method is not dependent on the GPCP.
In operation, as the MS tries to move into GAN,
the MS obtains the GAN PLMN list somehow, then updates the
user preferred PLMN list stored in memory by sorting the
PLMN5 according to those that offer GAN service. The MS
then performs PLMN selection based on the list.
More generally, over time, the MS learns which
PLMN5 support both a first network type and a second network
type, and prioritizes such PLMN5 above others. The MS then
performs PLMN selection based on the prioritization.
A related embodiment provides a mobile station
comprising a first wireless access radio for accessing
networks of a first network type; a second wireless access
radio for accessing networks of a second network type; a
network selector configured to perform network selection
using a PLMN list within listing networks of a first network
type such that a PLMN on the list that also supports a
second network type is prioritized. For mobile station
priorization, the mobile station may further comprise a PLMN
prioritorizer configured to determine the PLMN list of
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networks of a first network type such that a PLMN on the
list that also supports a second network type is prioritized
is performed by the MS on the basis of past behaviour
observed by the MS.
Sections in 3GPP TS 31.102 define EF5(i.e. section 5.3.6 for
the EFPLMNWACT, and section 5 .3.20 for the EFOPLMNWACT, section 4.2.54
for the EFHPLMNWAcT) for network or user prioritization.
These EFs contains the coding for n PLMN5 where n
is determined by the operator. This information is
determined by the user (EFPLMNWACT) or the operator (EFPLMMNWACT,
EFHPLMNWAcT) and defines the preferred PLMN5 in priority order.
The first record indicates the highest priority and the nth
record indicates the lowest. The EFs also contain the Access
Technologies for each PLMN in the list. (see 3GPP TS 23.122)
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Identifier: Structure: Optional
'6F61' transparent
SFI: '11'
File size: 5n bytes , (n Update activity: low
8)
Access Conditions:
READ
PIN
UPDATE ADM
DEACTIVATE ADM
ACTIVATE ADM
Bytes Description M/O Length
1 to 3 1St PLMN (highest M 3 bytes
priority)
4 to 5 1St PLMN Access Technology M 2 bytes
Identifier
36 to 38 8th PLMN M 3 bytes
39 to 40 8th PLMN Access Technology M 2 bytes
Identifier
41 to 43 9th PLMN 0 3 bytes
44 to 45 9th PLMN Access Technology 0 2 bytes
Identifier
(5n-4) to Nth PLMN (lowest priority) 0 3 bytes
(5n-2)
(5n-1) to Nth PLMN Access Technology 0 2 bytes
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5n (Identiier
The HPLMN Selector with access technology data field shall
contain the HPLMN code, or codes together with the respected
access technology in priority order (see 3GPP TS 23.122).
- PLMN
5 Contents:
Mobile Country Code (MCC) followed by the Mobile
Network Code (MNC).
Coding:
- according to 3GPP TS 24.008.
10 Register Update contains PLMN Continuity Information
The above-described behaviour has focussed on the
case where the PLMN continuity preference information is
included in the Registration Request. In some embodiments,
the MS does not include the PLMN continuity information in a
15 registration request to a Default GANC and/or the MS
includes this information but the Default GANC does not take
it into account, and in response to that the MS may send a
registration update message containing the PLMN continuity
information. Registration is accepted by the Default GANC
20 even though a PLMN mismatch exists. In response to this, the
MS detects the existence of a PLMN mismatch and the MS sends
a REGISTER UPDATE message to request that the current
Serving GANC (which is the Default GANC in this case) send
the GAN PLMN list.
25 In some embodiments, the MS signals GAN PLMN
continuity preference to the Serving GANC upon detecting the
PLMN mismatch, for example as part of the REGISTER UPDATE
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message. This may, for example involve including one of the
optional information elements for the Required GAN Services
IE or the PLMN Continuity IE as described previously.
Application to Networks other than Cellular and WLAN
The embodiments described above all refer to WLAN
access points, and to the movement between cellular and GAN.
More generally, embodiments are applicable for moving
between a network having a first network type, and a
network having a second network type that is different from
the first network type. A non-limiting set of examples of
network types include GSM, UTRAN, E-UTRAN or EPS, WLAN,
WiMAX, WiBRO, UMB, etc. In some embodiments, the first
network type is one that provides cellular connectivity, and
the second network type is one that provides wireless IP
connectivity.
Referring now to Figure 8, shown is a network
diagram depicting an example access scenario. Shown is a MS
210, a plurality of access points (AP) 222,224,226, a
network cloud 228, a Network Interworking Node (NIN) 230,
and a legacy NIN 240. Each NIN 230,240 is responsible for
coordinating the interworking between a network of the first
type and a network of a second type. A GANC is a specific
example of a NIN that is particular to the GAN-Cellular
interworking case. At the instant depicted, the MS 210 has
wireless connectivity to access point 222. More generally,
the discussion presented herein applies to access scenarios
in which there are any number of MSs, any number of access
points, and any number of NIN5. Network cloud 228
represents any network connectivity between the access
points 222,224,226 and the network interworking nodes
230,240. This may for example include parts of the public
Internet and or private networks.
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The MS 210 has a first wireless network radio 212
through which communication takes place with a network of
the first network type. The MS 210 has a second wireless
network radio 214 for connecting to a network of the second
network type. The MS 210 has a NIN selector 216 responsible
for deciding if and when to attempt to register with a
network having the second network type, and for deciding
which NIN to register with. The MS has a PLMN continuity
preference storage element 218 for storing a PLMN continuity
preference (PCP). Note that the GPCP is a specific example
of the PCP. The PCP is conceptually the same as the GPCP
described previously, but is now applicable for the
preference in maintaining continuity when moving between
networks of two different types that need not be GAN and
cellular. The preference can be stored in any suitable
form; specific examples include a token or an identifier.
This storage element can be in internal or external memory
of any appropriate form.
NIN 230 is a GANC that is configured to recognize
the PLMN continuity preference information when received
from a MS such as MS 210. The NIN 230 has a registration
request handler 232 responsible for processing registration
requests. The registration request handler 232 has a PLMN
continuity preference processing function 234 which takes
into account a PLMN continuity preference received from a
MS. In some embodiments, the GANC 230 also includes a PLMN
continuity preference configurator 236 for configuring the
PLMN continuity preference on a MS. In some embodiments,
the NIN 30 also includes storage 238 for storing the PCP of
MSs. This might be for the purpose of configuring the PCP
of MSs in which case the PCP sends this information to the
MS. In another example, the PCP storage 238 is for storing
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the PCP received from an MS, for example in association with
an IP address or other identifier of the MS.
Legacy NIN 240 is a NIN which is not configured to
recognize the PLMN continuity preference information.
Some embodiments provide a mechanism for the MS to
send the PLMN continuity preference to a NIN, and for a NIN
such as NIN 230 to receive the PLMN continuity preference
information. Some embodiments provide mechanisms for a NIN
such as NIN 230 to make use of such PLMN continuity
preference information, and some embodiments provide
mechanisms for a MS such as MS 210 to make use of the PLMN
continuity preference information.
PLMN Continuity Preference Indication
A mechanism is provided that allows the MS to be
able to communicate to the network whether or not it
requires or would prefer to maintain PLMN continuity. In
some embodiments, the information from this field is used in
various registration messages, as described more fully
below.
Preference for PLMN continuity refers generally to
preferences for a MS in respect of the maintenance of
continuity of PLMN when moving between different network
types. This preference is referred to as the PLMN
continuity preference (PCP). In some embodiments, the PCP
is used to indicate one of four preferences. These four
specific preferences are described below. More generally,
the number of possible preferences, and their definitions,
may be different than this specific example.
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PLMN Continuity Required
Generally, the PLMN Continuity Required preference
indication is used to indicate that the MS requires PLMN
continuity.
PLMN Continuity Preferred
The MS may "prefer" PLMN continuity and can use
the PLMN Continuity Preferred indication.
NIN Associated with HPLMN or EHPLMN required
The NIN Associated with HPLMN or EHPLMN required
indication is the case where the user (or the user's
operator) wants to force the MS to use a NIN associated with
the HPLMN or EHPLMN.
No Preference
The No Preference indication is used to indicate
that there is no restriction on the NIN used.
Referring now to Figure 7, shown is a block
diagram of a wireless device 100 that may, for example,
implement any of the MS methods described in this
disclosure. The wireless device 100 is operable for
implementing aspects of the disclosure, but the disclosure
should not be limited to these implementations. Though
illustrated as a mobile phone, the wireless device 100 may
take various forms including a wireless handset, a pager, a
personal digital assistant (PDA), a portable computer, a
tablet computer, or a laptop computer, wireless or wired or
fixed devices including standard wired telephone handset,
set-top boxes, and the like. Many suitable devices combine
some or all of these functions. In some embodiments of the
disclosure, the wireless device 100 is not a general purpose
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computing device like a portable laptop or tablet computer,
but rather is a special-purpose communications device such
as a mobile phone, wireless handset, pager, or PDA. In
another embodiment, the wireless device 100 may be a
5 portable laptop or other computing device. The wireless
device 100 may support specialized activities such as
gaming, inventory control, job control, and/or task
management functions, and so on. It is to be understood
that the wireless device 100 is shown with very specific
10 details for exemplary purposes only. A processing device (a
microprocessor 128) is shown schematically as coupled
between a keyboard or other user interface 114 and a display
126, which may also operate as a user interface. The
microprocessor 128 controls operation of the display 126, as
15 well as overall operation of the wireless device 100, in
response to actuation of keys on the keyboard 114 or other
user interface by a user.
The wireless device 100 has a housing that may be
elongated vertically, or may take on other sizes and shapes
20 (including clamshell housing structures). The keyboard 114
may include a mode selection key, or other hardware or
software for switching between text entry and telephony
entry.
In addition to the microprocessor 128, other parts
25 of the wireless device 100 are shown schematically. These
include: a communications subsystem 170; a short-range
communications subsystem 102; the keyboard 114 and the
display 126, along with other input/output devices including
a set of LEDs 104, a set of auxiliary I/O devices 106, a
30 serial port 108, a speaker 111 and a microphone 112; as well
as memory devices including a flash memory 116 and a Random
Access Memory (RAM) 118; and various other device subsystems
120. The wireless device 100 may have a battery 121 to
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power the active elements of the wireless device 100. The
wireless device 100 is in some embodiments a two-way radio
frequency (RF) communication device having voice and data
communication capabilities. In addition, the wireless
device 100 in some embodiments has the capability to
communicate with computer systems via the Internet.
Operating system software executed by the
microprocessor 128 is in some embodiments stored in a
persistent store, such as the flash memory 116, but may be
stored in other types of memory devices, such as a read only
memory (ROM) or similar storage element. In addition,
system software, specific device applications, or parts
thereof, may be temporarily loaded into a volatile store,
such as the RAM 118. Communication signals received by the
wireless device 100 may also be stored to the RAM 118.
The microprocessor 128, in addition to its
operating system functions, enables execution of software
applications on the wireless device 100. A predetermined
set of software applications that control basic device
operations, such as a voice communications module 130A and a
data communications module 130B, may be installed on the
wireless device 100 during manufacture. In addition, a
personal information manager (PIM) application module 130C
may also be installed on the wireless device 100 during
manufacture. The PIM application is in some embodiments
capable of organizing and managing data items, such as e-
mail, calendar events, voice mails, appointments, and task
items. The PIM application is also in some embodiments
capable of sending and receiving data items via a wireless
network 110. In some embodiments, the data items managed by
the PIM application are seamlessly integrated, synchronized
and updated via the wireless network 110 with the device
user's corresponding data items stored or associated with a
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host computer system. As well, additional software modules,
illustrated as another software module 130N, may be
installed during manufacture.
Communication functions, including data and voice
communications, are performed through the communication
subsystem 170, and possibly through the short-range
communications subsystem 102. The communication subsystem
170 includes a receiver 150, a transmitter 152 and one or
more antennas, illustrated as a receive antenna 154 and a
transmit antenna 156. In addition, the communication
subsystem 170 also includes a processing module, such as a
digital signal processor (DSP) 158, and local oscillators
(LOs) 160. The communication subsystem 170 having the
transmitter 152 and the receiver 150 includes functionality
for implementing one or more of the embodiments described
above in detail. The specific design and implementation of
the communication subsystem 170 is dependent upon the
communication network in which the wireless device 100 is
intended to operate. For example, the communication
subsystem 170 of the wireless device 100 may be designed to
operate with the MobitexTM, DataTACTM or General Packet Radio
Service (GPRS) mobile data communication networks and also
designed to operate with any of a variety of voice
communication networks, such as Advanced Mobile Phone
Service (AMPS), Time Division Multiple Access (TDMA), Code
Division Multiple Access (CDMA), Personal Communications
Service (PCS), Global System for Mobile Communications
(GSM), etc. Examples of CDMA include 1X and lx EV-DO. The
communication subsystem 170 may also be designed to operate
with an 802.11 Wi-Fi network, and/or an 802.16 WiMAX
network. Other types of data and voice networks, both
separate and integrated, may also be utilized with the
wireless device 100.
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Network access may vary depending upon the type of
communication system. For example, in the MobitexTM and
DataTACTM networks, wireless devices are registered on the
network using a unique Personal Identification Number (PIN)
associated with each device. In GPRS networks, however,
network access is typically associated with a subscriber or
user of a device. A GPRS device therefore typically has a
subscriber identity module, commonly referred to as a
Subscriber Identity Module (SIM) card, in order to operate
on a GPRS network.
When network registration or activation procedures
have been completed, the wireless device 100 may send and
receive communication signals over the communication network
110. Signals received from the communication network 110 by
the receive antenna 154 are routed to the receiver 150,
which provides for signal amplification, frequency down
conversion, filtering, channel selection, etc., and may also
provide analog to digital conversion. Analog-to-digital
conversion of the received signal allows the DSP 158 to
perform more complex communication functions, such as
demodulation and decoding. In a similar manner, signals to
be transmitted to the network 110 are processed (e.g.,
modulated and encoded) by the DSP 158 and are then provided
to the transmitter 152 for digital to analog conversion,
frequency up conversion, filtering, amplification and
transmission to the communication network 110 (or networks)
via the transmit antenna 156.
In addition to processing communication signals,
the DSP 158 provides for control of the receiver 150 and the
transmitter 152. For example, gains applied to communication
signals in the receiver 150 and the transmitter 152 may be
adaptively controlled through automatic gain control
algorithms implemented in the DSP 158.
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In a data communication mode, a received signal,
such as a text message or web page download, is processed by
the communication subsystem 170 and is input to the
microprocessor 128. The received signal is then further
processed by the microprocessor 128 for an output to the
display 126, or alternatively to some other auxiliary I/O
devices 106. A device user may also compose data items,
such as e-mail messages, using the keyboard 114 and/or some
other auxiliary I/O device 106, such as a touchpad, a rocker
switch, a thumb-wheel, or some other type of input device.
The composed data items may then be transmitted over the
communication network 110 via the communication subsystem
170.
In a voice communication mode, overall operation
of the device is substantially similar to the data
communication mode, except that received signals are output
to a speaker 111, and signals for transmission are generated
by a microphone 112. Alternative voice or audio I/O
subsystems, such as a voice message recording subsystem, may
also be implemented on the wireless device 100. In
addition, the display 126 may also be utilized in voice
communication mode, for example, to display the identity of
a calling party, the duration of a voice call, or other
voice call related information.
The short-range communications subsystem 102
enables communication between the wireless device 100 and
other proximate systems or devices, which need not
necessarily be similar devices. For example, the short
range communications subsystem may include an infrared
device and associated circuits and components, or a
BluetoothTM communication module to provide for communication
with similarly-enabled systems and devices.
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In some implementations, the wireless device 100
is capable of operating in multiple modes such that it can
engage in both CS (Circuit-Switched) as well as PS (Packet-
Switched) communications, and can transition from one mode
5 of communications to another mode of communications without
loss of continuity. Other implementations are possible.
Numerous modifications and variations of the
present application are possible in light of the above
teachings. It is therefore to be understood that within the
10 scope of the appended claims, embodiments may be practiced
otherwise than as specifically described herein.
