Core Wireless Licensing S.a.r.l. v. Apple, Inc.

Filing 1

COMPLAINT against Apple, Inc. ( Filing fee $ 350 receipt number 0540-3468392.), filed by Core Wireless Licensing S.a.r.l.. (Attachments: # 1 Civil Cover Sheet, # 2 Exhibit 1 - United States Patent No. 6,792,277, # 3 Exhibit 2 - United States Patent No. 7,606,910, # 4 Exhibit 3 - United States Patent No. 6,697,347, # 5 Exhibit 4 - United States Patent No. 7,447,181, # 6 Exhibit 5 - United States Patent No. 6,788,959, # 7 Exhibit 6 - United States Patent No. 7,529,271, # 8 Exhibit 7 - United States Patent No. 6,266,321, # 9 Exhibit 8 - United States Patent No. 6,978,143, # 10 Exhibit 9 - Nokias June 14, 2011 press release)(Hill, Jack)

EXHIBIT 1

111111

1111111111111111111111111111111111111111111111111111111111111
US006792277B2

United States Patent

(10)

Rajaniemi et ai.

(12)

(45)

(54)

Inventors: Jaakko Rajaniemi, Helsinki (FI);
Heikki Einola, Espoo (FI)

(73)

Assignee: Nokia Corporation, Espoo (FI)

( *)

Notice:

6,212,380
6,212,390
6,212,391
6,285,667
6,292,667
6,295,455
6,301,479
6,356,763
6,363,252
6,397,065

ARRANGING CONTROL SIGNALLINGS IN
TELECOMMUNICATIONS SYSTEM

(75)

Subject to any disclaimer, the term of this
patent is extended or adjusted under 35
U.S.c. 154(b) by 0 days.

(21)
(22)

Filed:

Dec. 27, 2001

Continuation of application No. PCT/FIOO/00595, filed on
Jun. 29, 2000.

(51)
(52)

(58)

(FI) ................................................. 991521

Int. CI? .................................................. H04Q 7/20
U.S. CI. ................................ 455/456.1; 455/432.1;
455/432.2; 455/433; 455/414.2; 455/435.1;
455/458; 455/456.2; 455/461; 455/435
Field of Search ................................. 455/426, 432,
455/433, 435, 436, 456, 458, 461, 439,
432.15, 435.1, 447, 456.1, 456.2
References Cited

(56)

U.S. PATENT DOCUMENTS
5,711,001
5,815,816
5,835,061
6,032,042

A
A
A
A

*
*
*
*

1/1998
9/1998
11/1998
2/2000

Laatu ......................... 455/436
Rune .......................... 455/410
Saleh et al. .............. 455/456.4
Willars et al. .............. 370/329
Wallentin et al. ........... 455/435
Fischer et al. ........... 455/456.2
Roobol et al. .............. 455/410
Kangas et al. ........... 455/456.1
Hamalainen et al. ....... 455/436
Huusko et al. ............. 455/426

97/26739
98/37721
98/37721 A3
98/37721 A2

7/1997
8/1998
8/1998
8/1998

* cited by examiner
Primary Examiner-Marceau Milord
(74) Attorney, Agent, or Firm-Pillsbury Winthrop LLP

Foreign Application Priority Data

Jul. 2, 1999

4/2001
4/2001
4/2001
9/2001
9/2001
9/2001
10/2001
3/2002
3/2002
5/2002

Berruto et aI., "Research Activities on UMTS Radio Interface, Network Architectures and Planning," IEEE Communications Magazine, vol. Feb. 1998, pp. 89-91, FIgures 6-9.

Related U.S. Application Data

(30)

*
*
*
*
*
*
*
*
*
*

OTHER PUBLICATIONS

US 2002/0086670 A1 Jul. 4, 2002

(63)

WO
WO
WO
WO

Prior Publication Data

(65)

B1
B1
B1
B1
B1
B1
B1
B1
B1
B1

FOREIGN PATENT DOCUMENTS
WO
WO
WO
WO

Appl. No.: 10/026,948

Patent No.:
US 6,792,277 B2
Date of Patent:
Sep.14,2004

Bussan et al. ........... 455/432.1
Isumi ......................... 455/445
Stewart ...................... 342/457
Kauppi ....................... 455/432

ABSTRACT

(57)

Implementing control signallings in a telecommunication
system comprising at least one terminal and one telecommunication network, the telecommunication network comprising at least one access network and one or more core
networks. Within a certain time, the terminal determines the
detected control signalling needs and transmits a request for
maintaining a radio connection to the telecommunication
network if several control signallings are to be carried out.
The control signallings are carried out successively between
the terminal and one or more core networks without releasing the radio connection between the terminal and the access
network.
27 Claims, 3 Drawing Sheets

IWF1

MS~

AN

IWF20

IWF3

"--t

CN2

CN3

u.s.

Patent

Sep.14,2004

Sheet 1 of 3

US 6,792,277 B2

CN1

MSJ:j

IWF20.

IWF3

Fig. 1

[ ......... ~..~.~; ........................j

l'

Fig.2

"--i

CN2

CN3

u.s. Patent

Sep.14,2004

Sheet 2 of 3

C23

C21

C11

LA1

/ /....................... .

US 6,792,277 B2

LA2

~;~')~;~

C12

C32

LA3
C31

Fig. 3

MS

RNC

MSC

SGSN

RRC setup reques
RRC connection

SE

tup

LU request

MS LU request

LU accept
signalling release re ~uest
signalling release co rnplete
RAU request
MS RAU request
RAU accept
bearer release reqUE st
bearer release

_.....

com~

-'-

lete

-'-

Fig.4

_.....

u.s.

Patent

MS

Sep.14,2004

Sheet 3 of 3

RAN

US 6,792,277 B2

CN2

signalling messag l 1

message1 reply
release lu-signalling
signalling messagE 2
message2 reply
release signalling

Fig. 5

US 6,792,277 B2
1
ARRANGING CONTROL SIGNALLINGS IN
TELECOMMUNICATIONS SYSTEM

2

packet switched services. The packet-switched services can
be based on a general packet radio service GPRS service in
the GSM. The circuit-switched and packet-switched connections are controlled by different network elements that
This is A Continuation application of PCT/FIOO/00595,
which was filed on Jun. 29, 2000 in the English language. 5 can thus form, at least in part, operationally separate core
The present invention relates to a method, a telecommunetworks (or domains, as they can also be called). Location
nication system, a network element of the telecommunicaareas and mobility management can then also differ even
though the mobile station communicates via the same access
tion system and a terminal for arranging control signallings
network.
according to the preambles of the independent claims.
Since in the UMTS system the core networks may be
In telecommunication systems, in addition to the actual 10
user data to be transmitted, such as speech information, for
separate from each other, separate and possibly different
example, a large amount of different control information is
control signalling functions may be necessary between each
transmitted between different parts of a network. In the
core network and mobile station for location update, for
telecommunication systems, a great amount of different
example. In connection with the present application, netcontrol signalling is carried out between a terminal and a 15 works elements responsible for the circuit- and packettelecommunication network for identifying a user or for
switched connections in the UMTS system are treated as
transmitting service requests, for example.
separate core networks. Different core networks can still
A purpose of mobile communication systems is to prooperate controlled by a common network management and
use common network elements, such as a home location
vide mobile users with wireless data transmission services.
Hence, it is essential, particularly in the mobile communi- 20 register HLR, which comprises subscriber information.
cation systems, that a mobile communication network is
Mobile stations are being developed for the UMTS
aware of the location of a mobile station registered therein.
system that can support several different core networks. In
Various mobility management protocols have been develthe UMTS system, one mobile station can have several
oped for this purpose.
simultaneous connections to different core networks, such as
In order to reduce unnecessary signalling, the mobile 25 a circuit- and packet-switched connection, for example. The
communication systems have typically been arranged such
mobile station can be registered in more than one core
that in mobile terminated connections, a subscriber is paged
network. Hence, it may be necessary in the UMTS system to
within the area of only a few base stations. Each base station
carry out separate control signalling functions between the
has a certain coverage area, which forms a cell. Cells form
mobile station and a plurality of core networks for location
location areas, and a mobile station is paged only in the cells 30 update, for example.
In the UMTS system, the mobile station may monitor
in the location area. Consequently, in order to obtain services
location area identifiers of several different core networks
from a serving base station, the mobile station must inform
broadcast by the UMTS access network. The mobile station
the mobile communication system of the location area
within which the subscriber can be paged. The mobile
may then, when more than one location area changes, have
station can carry out location update for the purpose. Loca- 35 a need to carry out several location updates over a short
tion update can thus be used to update the subscriber
period of time. For this purpose, the mobile station reserves
location information in the network and possibly also to
a radio connection for signalling from the access network
carry out other procedures. For example, a network accordand transmits a location updating message to a core network.
ing to a GSM system can transmit information about availWhen the location update is completed, the radio connection
able services to the mobile station in connection with 40 between the mobile station and the access network is
location update.
released.
So-called third generation mobile communication sysIf the mobile station is to carry out location update to
tems have been developed worldwide. A 3 rd generation
another core network, the radio connection must be
partnership project 3GPP standardizes a third generation
re-established. Although the access network is common to
mobile communication system called a universal mobile 45 different core networks, the radio connection must be
released and re-established between different location
telecommunications system UMTS based on the GSM
updates. A similar procedure must also take place in subsystem, which, for example, includes a new radio interface.
stantially successive control signallings of other kinds even
The UMTS radio interface will be based on at least a
wideband code division multiple access WCDMA technolif the control signalling to a second core network were
ogy.
50 carried out soon after the control signalling to a first core
FIG. 1 generally illustrates a mobile communication
network. This causes signalling load over the radio interface
system, such as the UMTS system, according to the third
and is thus against general design objectives that try to
minimize signalling over the radio interface.
generation principles. The development of the UMTS aims
for flexibility, whereby a so-called access network AN can
An object of the invention is thus to provide a method
be connected to many different core networks CNl, CN2 55 and an apparatus implementing the method so as to alleviate
and CN3. Since the core networks can vary greatly in their
the above-mentioned drawback. The objects of the invention
operation, interworking functions IWFl, IWF2 and IWF3
are achieved by a method, a telecommunication system, a
may be necessary between the access network AN and each
network element of the telecommunication system and a
core network. In connection with the present application, an
terminal characterized in what is disclosed in the indepenaccess network refers to a network which provides the 60 dent claims. Preferred embodiments of the invention are
disclosed in the dependent claims.
mobile station MS with a radio connection, in other words
The idea underlying the invention is that the connection
typically to a base station system.
between the access network and the terminal is not released
As far as the core networks are concerned, the UMTS
will probably, at least in part, be based on the GSM system,
between substantially successive control signallings
in which case connection management and mobility man- 65 between at least one core network and the terminal. The
access network maintains the connection after the control
agement in the UMTS will be mostly similar to those in the
signalling between the core network and the terminal for
GSM system. The UMTS will enable circuit-switched and

US 6,792,277 B2

3

4

another potential need. According to a preferred embodiment of the invention, the need to maintain the connection
between the access network and the terminal can be detected
by means of a predetermined time limit in the terminal. A
solution of the invention has the advantage that several
substantially successive control signallings can be carried
out without releasing and re-establishing the connection
between the access network and the terminal between the
signallings, which means that signalling over the radio
interface at issue is reduced. The invention can particularly
well be applied to different mobile communication systems
providing a radio connection, in which case the terminal is
a mobile station. Hence, the amount of signalling to be
carried out over the radio interface can be reduced.
According to a preferred embodiment of the invention,
the terminal determines the core networks to which control
signallings are to be carried out by utilizing the time limit
and transmits a request for maintaining the connection
between the access network and the terminal to the telecommunication network. On the basis of the request, the
connection will be maintained until the control signallings to
all core networks have been carried out. According to
preferred embodiments of the invention, the terminal can
transmit to the telecommunication network information
about the number of control signallings and/or core networks to which control signallings are to be carried out. The
advantage achieved is that when the control signallings are
directed to a plurality of core networks, the connection can
be maintained in the telecommunication network on the
basis of the information transmitted by the terminal only for
the necessary period of time.
According to a preferred embodiment of the invention, in
the telecommunication system a timer can be set to control
as to how long the connection between the access network
and the terminal is maintained. The connection can then be
maintained only for a restricted period of time particularly in
case of error situations.
Control signallings can be, for example, location updates
to several different core networks. The request for maintaining the connection between the access network and the
terminal can be transmitted either to the access network or
the core network.
The invention is now described in closer detail in connection with the preferred embodiments and with reference
to the accompanying drawings, in which
FIG. 1 generally shows a UMTS system,
FIG. 2 shows a UMTS mobile communication system in
closer detail,
FIG. 3 illustrates a location area structure of a mobile
communication system,
FIG. 4 is a signalling diagram showing, by way of
example, control signalling according to a preferred embodiment of the invention, and
FIG. 5 is a signalling diagram showing, by way of
example, control signalling of a preferred embodiment of
the invention.
In the following, the primary embodiments of the invention will be described in a mobile communication system
according to the UMTS principles without any intention to
restrict the invention to the UMTS system. The invention is
suitable for use in any telecommunication system wherein a
need exists to carry out a plurality of substantially successive control signallings between a terminal and a telecommunication network. The control signallings can be carried
out for different services or different network elements, for
example.
The invention can be applied to an access network
connected to at least two core networks when it is necessary

to carry out separate control signallings between the core
networks and the terminal. Different network elements,
which can possibly be in the same network, may form
operatively different core networks. For example, one network may comprise different network elements supporting
mobility management protocols which require separate control signallings. The invention can thus be applied to implementing control signallings to different core networks, the
need for control signallings preferably being detected within
a time limit set in the terminal.
The invention can also be applied to telecommunication
systems with only one core network integrated to be responsible for several different services, such as circuit- and
packet-switched connections. Also then, it may be necessary
to separately carry out control signallings for circuit- and
packet-switched services.
FIG. 2 shows, by way of example, a mobile communication network UMTS NW according to the UMTS system
comprising an access network RAN and two core networks
CNl and CN2. A mobile station MS comprises actual mobile
equipment ME and a UMTS subscriber identity module
USIM, also called a subscriber identification unit, typically
detachably connected thereto. The US 1M is preferably
stored on a smart card VICC (UMTS IC card), which can be
changed from a mobile station to another. Thus in this
connection, a mobile station generally refers to an entity
comprising a subscriber identification unit and actual mobile
equipment.
The radio access network RAN, i.e. the UMTS base
station system, is responsible mainly for matters associated
with the radio path, in other words it provides the core
networks and mobile stations with radio access necessary for
wireless operation. The RAN comprises one or more base
stations BSl, BS2, and a radio network controller RNC
controlling the radio frequencies available to the base stations BSl, BS2. The radio network controller RNC communicates with one or more core networks CNl, CN2 over
an interface lu.
The core network is a conventional telecommunication
network or a future telecommunication network modified to
efficiently utilize the access network in the wireless communication. The core network provides a connection to other
systems or networks, such as other UMTS networks, data
networks and public telephony networks. FIG. 2 shows core
networks CNl, CN2 based on the GSM/GPRS system as
examples.
The core network CNl is responsible for circuit-switched
services. The core network CNl comprises a mobile switching centre MSC, which is responsible for connection setup
and routing of the circuit-switched services to correct
addresses. Two databases comprising information on mobile
subscribers are utilized for the purpose: a home location
register HLR and a visitor location register VLR. The mobile
switching centre typically also comprises the functions of
the visitor location register, exemplified by an MSCNLR in
FIG. 2. The mobile switching centre MSC communicates
with other telecommunication networks, such as a public
switched telephone network PSTN or an integrated services
digital network ISDN, by means of an interworking function
IWF.
The core network CN2 is responsible for providing
packet-switched services. The CN2 comprises a serving
GPRS support node SGSN based on the GPRS system
responsible for connection setup and routing of the packetswitched services to correct addresses. The SGSN maintains
location information on the mobile station by utilizing, when
necessary, the home location register HLR common both to

S

10

15

20

25

30

35

40

45

50

55

60

65

US 6,792,277 B2
5

6

the core networks CNI and CN2. A GPRS gateway support
Each base station BS broadcasts in its cell the location
node GGSN based on the GPRS system enables communiarea identifiers of the location areas of all core networks
cation with different packet data networks PDN. The SGSN
whereto the cell at issue belongs. The mobile station MS
and the MSC do not typically communicate with each other
monitors the broadcast location area identifiers of at least
directly; they may, however, have a Gs interface (not shown) 5 those core networks wherein it is active at the moment.
therebetween. As to a more detailed description of the
Each time the mobile station MS registered in the mobile
UMTS system, reference is made to the 3GPP UMTS
communication network changes location areas it sends the
specifications.
access network a location updating request, which causes
In order to transmit information between the mobile
the location information to be updated in the registers of the
station MS and the access network RAN, an RRC (radio 10
core network (or the access network). No location updates to
resource control) connection is always established therebethe core network will be carried out, however, if the mobile
tween. In order to transmit information between the access
station has an active connection to the core network at issue
network RAN and the core network, a so-called lu connecfor transmitting speech data of the user, for example. When
tion is established via an lu interface. In the UMTS system
the cell or the location area then changes, "handover" is
of FIG. 2, the radio network controller RNC establishes a
connection via the lu interface either to the mobile switching 15 carried out, in other words the active connection is handed
over to be dealt with by another base station. The location
centre MSC or the serving GPRS support node SGSN. After
update can also be carried out at certain intervals (periodic
the lu connection has been established, the radio network
location update). Furthermore, location update is carried out
controller RNC can transmit a location updating request, for
for registering the mobile station in a network and for
example, to a network element of the core network at issue.
Since one RRC connection may be used for different lu 20 bringing it to an "idle state" in the new area (a different
location area from the one at the previous registration time).
connections to different core networks, releasing the lu
connection between the core network and the access netAs was stated above, if the location area boundaries
between several different core networks are crossed subwork does not necessarily mean releasing the radio connection. If the mobile station MS has several simultaneous
stantially simultaneously, the mobile station is compelled to
connections to different core networks, the radio connection 25 transmit several location updating messages over the air
can be released only after the last lu connection has been
interface, one for each core network. An exception to this
released. In this respect, the UMTS differs from the GSM,
can be the use of a Gs interface between the network
where also the radio connection is released after releasing
elements MSC and SGSN of different core networks. In such
the lu connection. However, according to the known UMTS
a case, it can be possible to carry out location update for both
technology, the radio connection cannot be maintained 30 of them by one location updating message. However, the Gs
between successive control signallings, which means that
interface is not compulsory between these centres. In the
UMTS system, it may also be necessary to carry out other
the mobile station has only one control signalling connection
to a core network at a time.
separate control signallings, such as service requests, within
FIG. 3 illustrates location areas. A location area ordia short period of time to several different core networks
narily comprises a coverage area (cell) of several different 35 substantially successively.
base stations. A location area LAI of a core network
In the following, the invention will be described by way
comprises three cells Cll, Cl2 and C13. Similarly, a locaof example by means of the signalling diagram of FIG. 4 in
tion area LA3 comprises cells C31, C32 and C33. A location
location update where the mobile station moves from a cell
area LA2 comprises four cells C21, C22, C23 and C24. In
to another such that the location areas of two different core
fact, a location area is only a set of physical cells defined in 40 networks change. The mobile station MS can be registered
a database, and the identifier or name of the set is called a
in the core network CNI (for circuit-switched connections)
location area identifier. Furthermore, in principle an arbiand the core network CN2 (for packet-switched
trary number of different location area levels, such as
connections) of FIG. 2 through the access network RAN.
location areas of different sizes for different core networks,
The mobile station MS can move, for example, from the
can overlap.
45 base station BSI to the area of the BS2 in FIG. 2.
The location area of the packet-switched connections can
The essential point is that a need exists to carry out
also be called a routing area. It is feasible that location areas
location update to both core networks CNI and CN2 within
of different sizes are used in the packet-switched GPRS
a short period of time regardless of whether or not the
network from those used in the circuit-switched GSM netlocation areas of the core networks are the same. The mobile
work even if the two networks used a common access 50 station MS carries out the location updates substantially
network. The operators may, however, start using the same
successively, in other words the mobile station has only one
location areas both for the GSM and the GPRS core netcontrol signalling connection to the core network at issue at
a given time. The location area identifiers of the previous
works to simplify the network management. Even though
location update are stored in the mobile station, preferably
the location areas were not the same, situations will occur
wherein the location areas of both core networks change 55 in the USIM application. If the location areas are the same
when the mobile station moves.
to the core networks CNI and CN2, also the location area
The location areas of different core networks can prefidentifier can be the same for both networks.
erably be implemented such that they overlap, in other
Each base station of the access network RAN broadcasts
words such that one location area may comprise other
in its cell the location area identifiers of the location areas of
location areas. Hence, for example, the location area LA2 of 60 all core networks whereto the cell at issue belongs. The
location area information can preferably be transmitted in a
a first core network may encompass a location area of
broadcast control channel BCCH. The mobile station MS
another core network comprising cells C21 and C22. In such
a case, when the mobile station moves from cell C22 to cell
monitors the broadcast location area identifiers of at least
C32, for example, the location areas of both core networks
those core networks wherein it is registered (CNI and CN2)
change and the mobile station needs to carry out location 65 at the moment.
The mobile station detects that the location area identiupdate within a short period of time both to the first and the
second core network.
fiers of the core networks CNI and CN2 received from the

US 6,792,277 B2
7

8

access network are different from the location area identiThe RRC setup request may comprise a (maintain RRC)
fiers stored in the mobile station in connection with the
bit, for example, which indicates that the request for mainprevious location update. The mobile station has then moved
taining the radio connection is active. If the traffic situation
permits, the radio network controller RNC allocates the
from one location area to another and has to carry out
location update to both core networks CN! and CN2. 5 radio connection to the mobile station. The RNC detects that
Furthermore, the mobile station may detect, on the basis of
the request is active, so it maintains the radio connection
after the lu connection directed to the core network has been
the information transmitted by the access network, that
separate location updates must be carried out to the core
released.
networks. The location updates are preferably carried out
The radio network controller RNC and the base station
successively, first to the core network CN! and then to the 10 BS activate the radio connection to the mobile station MS.
The RNC transmits to the mobile station MS the radio
core network CN2, for example.
connection setup message comprising the necessary inforTransmitting the location updating request requires an
RRC connection to be established. The radio network conmation on the allocated radio connection (RRC connection
troller RNC controls the radio resources, so it is responsible
setup). The message may also comprise an acknowledgefor channel allocation when the mobile station or the core 15 ment of the maintenance of the radio connection after the lu
network so requests. According to a preferred embodiment
connection has been released. In order to set up the radio
of the invention, the location updates to different core
connection, the transmitter/receiver functions of the mobile
networks are carried out without releasing the radio constation MS are configured according to the received parameters.
nection.
The MS transmits the location updating request to the
According to a preferred embodiment of the invention, 20
radio network controller RNC by using the radio connection
the mobile station MS transmits a request to the access
network for maintaining the radio connection for later use.
already established to the core network CN! (LU request).
The location updating message typically comprises a subThe MS preferably transmits the request for maintaining the
radio connection also after the signalling to the core network
scriber identifier, such as a temporary mobile subscriber
CNl. The location update can then also be carried out to the 25 identity TMSI identifier, a packet-TMSI (P-TMSI) identifier
or an international mobile subscriber identity IMSI
core network CN2 without releasing the connection.
According to a preferred embodiment of the invention,
identifier, and typically at least the identifier of the old
the mobile station MS comprises the instructions on the
location area LAl. The RNC transmits the location updating
basis of which the MS decides to request that the radio
request to the mobile switching centre MSC of the core
connection be maintained. The mobile station preferably 30 network CN! (MS LU request). The location updating
request can preferably be transmitted in connection with the
comprises a predetermined time limit for detecting the need
lu connection setup message.
and making a request for maintaining the radio connection.
When necessary, security functions, such as authenticaWhen the need for control signalling is detected, it can be
tion (not shown), may be carried out between the MSC and
monitored whether a need arises within the time limit for
other control signallings. If within the time limit such a need 35 the mobile station MS. The MSC updates the necessary
registers according to the new location area. At least the
exists for other control signallings, a request for maintaining
the radio connection will be transmitted. If no need has
visitor location register VLR is typically updated in the
arisen within the time limit for other control signallings, no
location update. When the mobile switching centre/visitor
request will be transmitted to the mobile communication
location register changes, the home location register HLR is
network. The time limit is set so as to avoid too long a delay 40 also updated. Then, the HLR also transmits a request for
removing the location information on the mobile station to
before starting the control signalling.
In the following, it will be shown by way of example how
the old visitor location register. In the example, the location
the mobile station can transmit the request for maintaining
areas are, however, in the same visitor location register
the radio connection.
VLR, in which case the home location register HLR needs
A "follow on proceed" function has been standardized in 45 not be updated. The MSC transmits an acknowledgement of
the GSM system. The function enables the mobile station to
the location update to the mobile station MS (LU accept).
transmit, in a location updating request to the GSM mobile
After the location update has been carried out, the mobile
switching centre, a request for being allowed to use the radio
switching centre MSC transmits a message for releasing the
connection after the location update for other signalling
signalling connection (signalling release request) to the
associated with the location management. The location 50 radio network controller. Next, the lu connection between
the MSC and the RNC is released. According to the prior art,
updating request comprises a special "follow on proceed" bit
reserved for indicating the request for maintaining the radio
the RNC would also release the radio connection after the lu
connection to the mobile switching centre. The mobile
connection has been released. According to a preferred
embodiment of the invention, however, the RNC does not
switching centre in turn can, in a location updating acknowledgement (LOCATION UPDATING ACCEPT), indicate to 55 release the radio connection.
the mobile station that the radio connection can be used for
The radio connection is maintained if the mobile station
MS has requested for it, preferably when the radio connecsignalling associated with the location management directed
to the same mobile switching centre.
tion was being set up (RRC setup request). The (maintain
The "follow on proceed" function is not, however, suitRRC) bit then indicates that the radio connection is to be
able to be generally used for implementing several control 60 maintained. If no request for maintaining the radio connecsignallings, least of all if the control signallings are directed
tion has been set forth, the RNC releases the radio
to different core networks. According to a preferred embodiconnection, as requested by the core network. The informament of the invention, the mobile station MS transmits the
tion transmitted by the (maintain RRC) bit for maintaining
request to the mobile communication network, preferably to
the radio connection is preferably one of the RRC connecthe radio network controller RNC, for maintaining the radio 65 tion parameters in the radio network controller RNC.
According to a preferred embodiment of the invention,
connection for later use, preferably in connection with an
the radio network controller sets a time limit for maintaining
RRC setup request (RRC setup request).

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the radio connection. The radio network controller RNC
The location update to two different core networks
starts a timer preferably after the lu connection has been
described above when the mobile station is registered in the
released. If the time limit is exceeded, the radio network
UMTS system is only one example of how the invention can
controller RNC releases the radio connection even if no
be implemented.
According to a preferred embodiment of the invention,
control signallings were carried out after starting the timer. 5
the mobile station transmits information on the core netIt is thus possible to restrict the duration of maintaining the
works to which it is to carry out control signallings. In
radio connection in case of error situations, for example. If,
however, the control signalling is being carried out just when
connection with the request for maintaining the radio
the time limit is exceeded, the radio network controller RNC
connection, the mobile station can transmit the information
preferably releases the radio connection only after receiving 10 on the core networks to which control signallings are to be
a connection release request from the core network. The
carried out later on by using the same radio connection. This
timer can be started also after receiving the RRC setup
can be particularly necessary if the mobile station commurequest.
nicates with more than two core networks. The mobile
The RNC may transmit an acknowledgement of the
station can transmit the information on the core networks
release the lu connection to the mobile switching centre
preferably in the RRC setup request.
MSC (signalling release complete). The mobile switching 15
The access network, preferably the radio network concentre can thus be sure that the connection is released when
troller RNC, then maintains the radio connection until the
the signalling is over. The radio connection is, however,
control signallings, such as location updates, to the core
reserved for the mobile station for signalling even though no
networks at issue have been carried out. The RNC can
active lu connections were available.
maintain a register of the core networks to which control
After receiving the location updating acknowledgement 20 signallings have been carried out at a given time. After
control signallings have been carried out to all core networks
(LU accept), the mobile station detects that the location
update has been carried out. The mobile station can then
specified in the request, the radio connection is released
carry out the location update to the core network CN2 by
immediately when the last core network releases its lu
using the existing radio connection. In such a case, it has
connection. The mobile station can, for example, transmit
been unnecessary to separately release the radio connection 25 the information on the core networks whose location area it
after the first location update, so it is also unnecessary to
has detected to have changed or in which it is to be
re-establish the radio connection. Consequently, the amount
registered. Naturally, the duration of the radio connection
of signalling to be carried out over the radio interface is
can be controlled by using a timer, for example, as described
reduced.
above.
Furthermore, the invention can be applied in such a
The mobile station transmits the location updating 30
request to the core network CN2 to the radio network
manner that the mobile station transmits information about
controller (RAU request). Since the core network CN2 is a
how many different control signallings are to be carried out
GPRS network, the request can also be called a routing area
during the same radio connection. In such a case, the mobile
update request (RAU). The location update can then be
station can, preferably in connection with the request for
carried out according to the prior art known per se.
35 maintaining the radio connection, transmit information
The radio network controller RNC detects that the
about how many signalling connections are to be used.
The access network, preferably the radio network conmobile station requests location update to the core network
troller RNC, then maintains the radio connection until the
CN2, so the RNC transmits the location updating request to
number of control signallings announced by the mobile
the serving GPRS support node SGSN (MS RAU request).
If necessary, security functions, such as authentication (not 40 station has been carried out. The RNC can detect that each
control signalling has taken place when it receives the
shown), may be carried out between the SGSN and the
request for releasing the signalling connection from the core
mobile station. The SGSN updates the necessary registers
according to the new location area. After the location update
network. The RNC preferably counts how many control
has been carried out, the SGSN transmits an acknowledgesignallings have been carried out after the radio connection
ment of the location update to the mobile station (RAU 45 was activated. When the number of control signallings
accept).
announced by the mobile station is carried out, the radio
Furthermore, the SGSN transmits a message for releasconnection is released. The number of control signallings
ing the signalling connection to the radio network controller
required by the mobile station can then be carried out
RNC (bearer release request). The bearer release request
successively, and the radio connection is not maintained
over the lu interface can be similar to the signalling release 50 unnecessarily. A further advantage is that substantially sucrequest transmitted by the MSC. The lu connection is then
cessive control signallings can also be carried out to the
released, and the RNC preferably also releases the radio
same core network.
connection since the location update has been carried out to
The invention can be applied to any telecommunication
system wherein several control signallings are carried out
both core networks CN! and CN2. The (maintain RRC) bit
can then have been removed in the RNC during the second 55 substantially successively, in connection with activating the
location update. Releasing the radio connection is known
mobile station or location updates carried out at certain
per se; therefore, it is not shown in FIG. 4. The RNC
intervals, for example.
An example of another kind of signalling to which the
preferably acknowledges the signalling connection release
invention can be applied is transmitting two service requests
message transmitted by the SGSN (bearer release complete).
The invention can, however, also be applied in such a 60 to different core networks. The user of the mobile station
manner that the RNC does not release the radio connection
may then present a need for control signalling. The mobile
until the predetermined time limit is exceeded. The time
station MS may, within a predetermined time, for example,
limit is, however, preferably used only to restrict the reserdetect a need to transmit a short message via the core
vation of radio connections in case of errors. Also then it is
network CN! and a need to activate a GPRS connection to
advisable to transmit an acknowledgement to the SGSN so 65 the core network CN2.
as to prevent the SGSN from interpreting the situation as an
The mobile station can then transmit the request for
error situation.
maintaining the radio connection to the radio network con-

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troller RNC preferably in connection with activating the
comparison with the prior art are also required in the
radio connection. When the mobile station does not have any
implementation of the core network. In order to minimize
the changes required in the mobile communication network,
active traffic connections to the access network, the short
it is to be recommended that the invention should be
message is transmitted by using the signalling connection.
The radio network controller then maintains the radio con- 5 implemented such that the request for maintaining the radio
nection even if the short message has already been transconnection is transmitted to the access network. The changes
mitted to the core network CNI and the request for releasing
can be implemented by software, for example.
It is obvious to one skilled in the art that as technology
the signalling connection possibly already received from the
advances, the basic idea of the invention can be imp lemobile switching centre.
The mobile station can transmit the request for activating 10 mented in many different ways. The invention and its
embodiments are thus not restricted to the examples
the GPRS connection by using the existing radio connection.
When the signalling connection to the core network CN2 is
described above but they can vary within the scope of the
no longer needed, the radio network controller releases the
claims.
What is claimed is:
radio connection. Hence, the signalling to be carried out
1. A method of implementing control signallings in a
over the radio path can be reduced when the radio connec- 15
telecommunication system including at least one terminal
tion is not released between the service requests.
According to a preferred embodiment of the invention,
and one telecommunication network, the telecommunication
network including at least one access network and one or
the mobile station can also transmit the information about
more core networks, wherein the access network is conmaintaining the radio connection to the core network, which,
in turn, transmits the information to the access network in 20 nected to the core networks so that control signallings may
order to maintain the radio connection. In the following, this
be carried out between each core network and each terminal
via the access network, the method comprising:
embodiment will be described in a simplified manner by
means of FIG. 5.
detecting a need for a plurality of control signallings in the
The mobile station MS detects, within a predetermined
telecommunication system;
time limit, for example, that a need exists to carry out control 25
carrying out the plurality of control signallings between
signallings to the core networks CNI and CN2. When the
the terminal and at least one core network substantially
radio connection to the access network RAN has been
successively without releasing a connection established
established, the MS transmits the control signalling message
for control signalling between the terminal and the
to the core network CNI (signalling messagel). According
access network during a time period between the pluto a preferred embodiment of the invention, the message 30
rality of control signallings in response to the detecting.
comprises the information that the radio connection should
2. The method of claim 1, wherein a time limit for
be maintained after the signalling for later use. Furthermore,
detecting the need for the plurality of control signallings is
as described above, the message can comprise information
determined in the terminal, and the connection is maintained
on the core networks or the number of control signallings.
during the time period between the control signallings in
The core network CNI carries out the procedures 35 response to detection of the need for the plurality of control
required by the control signalling and transmits an acknowlsignallings within the time limit.
edgement to the mobile station MS (message 1 reply). Since
3. The method of claim 1, wherein the telecommunication
the lu connection is no longer needed between the access
system is a mobile communication system, the terminal is a
network and the core network CN1, the CNI transmits a
mobile station, and the connection is a radio connection.
request for releasing it (release lu-signalling). Preferably in 40
4. The method of claim 1, further comprising:
the same message, the core network CNI informs the access
the terminal determining the core networks to which a
network RAN that the radio connection is not released even
need for control signalling is detected,
if the lu connection is released. The message may also
the terminal transmitting a request for maintaining the
comprise more accurate information about maintaining the
connection established for control signalling between
radio connection, for example that the mobile station desires 45
the terminal and the access network to the telecommuto carry out control signalling to the core network CN2, and,
nication network,
after the signalling, the radio connection can be released.
The access network RAN then maintains the radio conneccarrying out control signalling between the terminal and
tion according to the instructions received from the core
a determined first core network,
network CN1.
50
carrying out control signallings between the terminal and
The MS carries out a second control signalling to the
other determined core networks, and
second core network CN2 by using the existing radio
releasing the connection established for control signalling
connection (signalling message2). The CN2 transmits an
between the terminal and the access network after the
acknowledgement to the mobile station MS (message2
control signallings have been carried out to all deterreply). Next, the CN2 transmits a request for releasing the 55
mined core networks.
signalling connection (release signalling), which can be
5. The method of claim 4, the method further comprising:
similar to the request transmitted by the core network CNI
determining, in the access network, in parameters of the
(release lu-signalling). On the basis of this, the lu connection
connections, that the connection should be maintained
is released and the access network further releases the radio
in response to said request transmitted by the terminal.
connection on the basis of the instructions received from the 60
6. The method of claim 4, wherein information about the
core network CN1.
number of necessary control signallings is transmitted in the
When applied to the mobile communication system, the
request for maintaining the connection,
invention can be implemented with relatively small changes
the access network counts the number of control signalin the mobile station and the access network. When a
lings carried out by the terminal, and
solution according to a preferred embodiment of the inven- 65
the connection established for control signalling between
tion is applied wherein information is transmitted to the core
the terminal and the access network is maintained until
network about maintaining the radio connection, changes in

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the number of control signallings announced by the
between the control signallings in response to detecting
terminal has been carried out.
the need for the plurality of control signallings within
the time limit.
7. The method of claim 4, wherein information about the
15. The telecommunication system of claim 13, wherein
core networks to which control signallings need to be carried
out is transmitted in the request for maintaining the 5 the telecommunication system is a mobile communication
system, the terminal is a mobile station, and the connection
connection,
is a radio connection.
the access network monitors to which core networks the
16. The telecommunication system of claim 13, wherein
control signallings are carried out, and
the terminal is configured to determine the core networks to
the connection established for control signalling between
10 which a need for control signalling is detected,
the terminal and the access network is maintained until
the terminal is configured to transmit a request for mainthe control signallings to all core networks identified in
taining the connection established for control signalling
the request have been carried out.
between the terminal and the access network to the
8. The method of claim 4, wherein the request for maintelecommunication network,
taining the connection is transmitted from the terminal to the
the terminal and a determined first core network are
15
access network.
configured to carry out control signalling,
9. The method of claim 8, wherein the request for mainthe terminal and other determined core networks are
taining the connection is transmitted from the terminal to the
configured to carry out other necessary control
access network in a setup request message of the connection.
signallings, and
10. The method of claim 4, wherein the request for
the access network is configured to release the connection
maintaining the connection is transmitted from the terminal 20
established for control signalling between the terminal
to the core network to which control signalling is carried out
and the access network after the control signallings
first,
have been carried out to the determined core networks.
a request for maintaining the connection is transmitted
17. The telecommunication system of claim 16, wherein
from the core network to the access network after the
25
the access network is configured to determine, in paramcontrol signalling, and
eters of the connection, that the connection should be
the control signallings are carried out between the termimaintained in response to the request transmitted by the
nal and other determined core networks without releasterminal.
ing the connection established for control signalling
18. The telecommunication system of claim 16, wherein
between the terminal and the access network.
the terminal is configured to transmit information about
11. The method of claim 1, wherein a time limit is set for 30
the number of necessary control signallings in the
maintaining said connection, and
request for maintaining the connection,
the connection established for control signalling between
the access network is configured to count the number of
the terminal and the access network is released when
control signallings carried out by the terminal, and
the time limit for maintaining the connection has been
exceeded even if all control signallings have not been 35
the access network is configured to maintain the conneccarried out.
tion established for control signalling between the
12. The method of claim 1, wherein
terminal and the access network until the number of
control signallings announced by the terminal has been
the control signallings to be carried out are location
carried out.
updates, and
19. The telecommunication system of claim 16, wherein
the terminal determines the core networks that need 40
the terminal is configured to transmit information about
location updating based on location information broadthe core networks to which control signallings need to
cast by the access network.
be carried out,
13. A telecommunication system comprising:
the access network is configured to monitor to which core
at least one terminal; and
45
networks the control signallings are carried out, and
one telecommunication network, the telecommunication
the access network is configured to maintain the connecnetwork including at least one access network and one
tion established for control signalling between the
or more core networks, the access network being conterminal and the access network until the control signected to the core networks,
nallings to all core networks mentioned in the request
wherein the at least one terminal is configured to detect a 50
have been carried out.
need for a plurality of control signallings in the tele20. The telecommunication system of claim 16, wherein
communication system;
the terminal is configured to transmit the request for
wherein the plurality of control signallings may be carried
maintaining the connection to the access network.
out between each core network and each terminal, and
21. The telecommunication system of claim 20, wherein
the access network is configured to maintain a connec- 55
the terminal is configured to transmit the request for maintion established for control signalling between the
taining the connection in a setup request message of the
terminal and the access network during a time period
connection.
between substantially successive control signallings of
22. The telecommunication system of claim 16, wherein
the plurality of control signallings between the terminal
the terminal is configured to transmit the request for
and at least one core network when the terminal detects 60
maintaining the connection to the core network to
a need for the plurality of control signallings.
which control signalling is carried out first,
14. The telecommunication system of claim 13, wherein
the terminal comprises means for determining a time limit
the core network is configured to transmit a request for
for detecting the need for the plurality of control signallings,
maintaining the connection to the access network after
and
the control signalling, and
65
the telecommunication network is configured to maintain
the access network is configured to maintain the connecthe connection established for control signalling
tion established for control signalling between the

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terminal and the access network between the control
terminal and the network element during a time period
signallings to other core networks.
between different, substantially successive control sig23. The telecommunication system of claim 13, wherein
nallings of the plurality of control signallings in
the access network is configured to set a time limit for
response to a request from the terminal when the
maintaining the connection established for control sig - 5
terminal detects a need for the plurality of control
nalling between the terminal and the access network,
signallings.
and
26. The network element of claim 25, wherein the netthe access network is configured to release the connection
work element is a radio network controller of an access
when the time limit for maintaining the connection has
10 network in the mobile communication system.
been exceeded even if all control signallings have not
27. A terminal comprising means for carrying out control
been carried out.
24. The telecommunication system of claim 13, wherein
signallings in a telecommunication system via an access
network to one or more core networks, wherein
the control signallings to be carried out are location
updates, and
15
the terminal is configured to detect a need for a plurality
the terminal is configured to determine the core networks
of control signallings in the telecommunication system,
that need location updating based on location informaand
tion broadcast by the access network.
the terminal is configured to transmit a request for main25. A network element of a telecommunication system,
wherein the network element is configured to provide a 20
taining the connection established for control signalling
connection for a terminal,
between the terminal and the access network to a
the terminal is configured to detect a need for a plurality
telecommunication network when the terminal detects
of control signallings in the telecommunication system;
a need for the plurality of control signallings.
the network element is configured to maintain the connection established for control signalling between the
* * * * *