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(12) 



Europaisches Patentamt 
European Patent Office 

Office europeen des brevets (1 1 ) 

EUROPEAN PATENT APPLICATION 

(51) int. Cl. s : H04Q 7/38, H04Q 7/22 



lillllllllllllllllllllllllllllllllllllll 

EP 0 788 287 A2 



(43) Date of publication: 

06.08.1997 Bulletin 1997/32 



(21) Application number: 97101730.6 

(22) Date of filing: 04.02.1997 



(84) Designated Contracting States: 


(72) Inventors: 


DE FR GB IT 


• Amin, Umesh J. 




Redmond, Washington 98052 (US) 


(30) Priority: 05.02.1996 US 597066 


• Redden, Michael 




Greenwich, Connecticut 06831 (US) 


(71 ) Applicant: AT&T Corp. 




New York, NY 1 001 3-241 2 (US) 


(74) Representative: KUHNEN, WACKER & PARTNER 




Alois-Steinecker-Strasse 22 




85354 Freising (DE) 



(54) Roaming authorization system 

(57) A roaming restriction system permits a wireless 
carrier or a subscriber to set a profile that identifies a 
chosen time window within which the subscriber's wire- 
less calls that are originated from one or more selected 
roaming areas, are not allowed to be completed, while 
calls that are initiated either from authorized roaming 



areas or outside the chosen time window are allowed to 
be completed. The roaming restriction system allows a 
wireless carrier to either suspend or grant roaming priv- 
ileges for a given subscriber within one or more location 
areas, and for a particular time window. 



1 



EP 0 788 287 A2 



2 



Description 

Technical Field of the Invention 

This invention relates to communications systems, 
and more specifically, to a method and system for 
authorizing wireless users to roam in selected radio 
coverage areas. 

Background of the Invention 

Over the last twenty years wireless communica- 
tions systems have evolved from their simple origins of 
single-operator wireless networks to multi -operator 
seamless roaming networks that allow wireless callers 
to receive and to initiate calls from wherever they might 
be - in their home service territory a in a roaming area 
that might even be located in a foreign country. A great 
number of technical and administrative obstacles had to 
be overcome before a subscriber of one wireless serv- 
ice provider could transparently receive wireless com- 
munications services from the network of another 
service provider. For example, multilateral operating 
agreements had to be negotiated between service pro- 
viders to standardize communications between the dis- 
similar switching systems of the different service 
providers' networks. Most importantly, a common sign- 
aling protocol and signaling messages format and defi- 
nition had to be agreed upon by all participating 
wireless service providers for exchange of call handling 
messages between their switching systems. 

Because of the significant differences in the com- 
munications systems architectures and switching sys- 
tems used by the different service providers, only a 
small number of common signaling messages for 
essential call processing functions (e.g., registration) 
could be agreed upon by the different service providers. 
As a result, a service provider-specific implementation 
for addressing a particular problem, such as wireless 
fraud, could not be universally adopted by all service 
providers. For example, the common practice that 
requires a wireless subscriber to provide authentication 
information before receiving service, could not be imple- 
mented for all roaming callers. The inability to imple- 
ment an authentication procedure for some roaming 
callers may be attributed to a variety of factors not the 
least of which is the home carriers' unwillingness to 
implement authentication procedures in their networks. 

Taking advantage of the lack of communications 
between switches for fraud prevention information, 
roaming areas have been targeted as launching pads to 
initiate fraudulent calls, thereby depriving wireless com- 
munications carriers of yearly revenues estimated at 
over half a billion dollars. Typical fraudulent ploys for the 
theft of wireless communications services include, for 
example, eavesdroppers intercepting legitimate sub- 
scriber's wireless telephone sets' Mobile Identification 
Numbers (MIN) and Electronic Serial Numbers (ESN) 
pairs from wireless communications frequencies, and 



publicizing those pairs over fraud-information-dissemi- 
nation forums, such as electronic bulletin boards. The 
intercepted MINs and ESNs pairs are then programmed 
into an illegal wireless device to enable a fraud perpe- 

5 trator to initiate roaming wireless calls that are charged 
to the legitimate subscribers' accounts 

In response to this ever-growing problem, some 
communications carriers have felt compelled to imple- 
ment additional fraud prevention measures that either 

10 deny or restrict access to their network for certain types 
of wireless calls. For example, some communications 
carriers have implemented drastic fraud prevention pro- 
cedures, such as denial of service for calls originated 
from particular roaming areas. 

is While these procedures have been quite effective in 
limiting incidences of wireless communications fraud, it 
is undeniable that they present certain shortcomings. 
For example, denying access to a wireless network for 
calls originated from certain roaming areas may have 

so the negative effect of possibly denying access to com- 
munications services to a great number of legitimate 
wireless subscribers when those services might be 
most needed. The denial of service is particularly vex- 
ing to a subscriber when no land-line communications 

25 services are available, as on a deserted road. Equally 
significant is the loss of roaming and air time charges 
and (possibly) long distance revenues that the service 
provider would have received as proceeds for the com- 
pletion of the denied calls. Hence, it is a continuing 

30 problem for wireless communications carriers to imple- 
ment fraud prevention measures that are neither unduly 
inconvenient to wireless subscribers nor overly reve- 
nue-limiting for wireless service providers. 

35 Summary pf the Invention 

The present invention is directed to a wireless net- 
work that grants roaming privileges to a wireless com- 
munications service subscriber for one or more selected 

40 roaming areas only during a limited time period that is 
identified in a profile of that subscriber. In an illustrative 
embodiment of the principles of the invention, a wireless 
communications service subscriber is allowed to set a 
profile that identifies a chosen time window within which 

45 wireless calls originated from one or more selected 
roaming areas are permitted to be completed while 
wireless calls that are initiated outside of the chosen 
time window and that are originated from any one of 
these selected roaming areas are automatically termi- 

50 nated. Similarly, calls initiated from unauthorized roam- 
ing areas are also terminated. 

The subscriber's profile may be, for example, a data 
structure, such as a table, that associates the sub- 
scriber's mobile end-user device MIN and/or ESN to the 

55 time window for the selected roaming area(s). Hence, 
when the subscriber powers on a mobile end-user 
device to register from a selected roaming area, the 
MIN and/or ESN associated with the mobile end-user 
device is used as a search key to retrieve the sub- 



2 



EP 0 788 287 A2 



4 



scriber's profile. The subscriber's profile may be stored, 
for example, at the Home Location Register of the sub- 
scriber's service provider. The current date, i.e., the 
date at which the registration process is initiated, is then 
compared to the time window information retrieved from 
the profile. If the current date falls within the range of 
permissible dates specified in the profile for the selected 
roaming area, the registration process proceeds in a 
conventional manner. Otherwise, a registration denial 
procedure may be initiated based, for example, on the 
subscriber's roaming history. 

According to an aspect of the invention, if the 
MIN/ESN pair associated with the mobile end-user 
device indicates, for example, that the subscriber is a 
frequent roamer, a call intercept feature may be acti- 
vated for the mobile end-user device. Hence, when a 
call is initiated from the mobile end-user device, the call 
is automatically routed to a live or automatic operator 
instead of its intended destination. The operator then 
prompts the caller for certain information to validate the 
caller's identity. If the information provided by the caller 
is valid, the call is then completed to its intended desti- 
nation. Otherwise, the call is terminated. 

According to another aspect of the invention, when 
fraud is detected for a given subscriber within a given 
roaming area, the serving wireless service provider can 
deny services to that particular subscriber either for a 
finite amount of time or on a permanent basis. Alterna- 
tively, services may be allowed or denied based "on the 
results of farther verification of the subscriber's identity. 

Brief Description of the Drawing 

In the drawings: 

FIG. 1 is a communications switching system 
arranged in accordance with the invention to allow 
wireless communications services providers to 
authorize wireless calls from selected roaming 
areas; 

FIGs. 2 and 3 are flow diagrams of call processing 
instructions executed by some of the components 
of FIG. 1 to register a mobile end-user device, and 
to complete wireless calls from selected roaming 
areas; 

FIG. 4 illustrates a profile that associates MINs and 
ESNs with selected roaming areas; and 

FIG 5 illustrates a table that correlates MINs and 
ESNs to a permissible roaming time period. 

Detailed Description 

Shown in FIG. Lis a multi-operator seamless roam- 
ing communications network that includes a land-line 
network 70, a wireless visiting network 104 and a wire- 
less home network 120. The land-line network 70 



includes interconnected local, tandem and toll switches 
(not shown) that enable a telephone call initiated from 
wired telephone 101 to be completed to another tele- 
phone set, such as set 80, or to be forwarded to wire- 

5 less network 1 20 or 1 04 for completion to a mobile end- 
user device such as wireless telephone set 10 or 20. 
Hereinafter mobile end-user devices 5, 10, 20 and 30 
are simply referred to as "mobiles'' 5, 10, 20 and 30. 
Each mobile is typically assigned a home network, 

io so that, at any given time, a particular mobile may be 
either located in its home network or roaming in another 
network. However in this example, for the sake of con- 
sistency and simplicity, wireless network 104 is labeled 
"visiting network" 104 while wireless network 120 is 

r5 called "home network" 120. This is done to more clearly 
separate the role of visiting network 104 (in which the 
roaming mobile 20 or 30 is currently located) from the 
functions of home network 120 (which is the wireless 
service provider for the owner of roaming mobile 20 or 

20 30). Specifically, visiting wireless network 104 is 
arranged to detect the presence of roaming mobiles 20 
and 30, and to inform home network 120 of that pres- 
ence. By contrast, home network 120 is responsible for 
communicating to visiting network 104 signaling infor- 

25 mation indicative of permission to grant roaming privi- 
leges to roaming mobiles 20 and 30. Other information 
transferred by home network 1 20 to visiting network 1 04 
includes a list of features subscribed to by the owner of 
roaming mobiles 20 and 30, as described in further 

30 detail below with reference to FIG. 4. Mobiles 20 and 30 
may use any conventional wireless technology for com- 
municating with visiting wireless network 104. For 
example, mobile 20 may be a conventional cellular tele- 
phone set while mobile telephone set 30 may be a low- 

35 mobility Personal Communications Service (PCS) end- 
user device. Although mobiles 20 and 30 are shown in 
FIG. 1 as a earphone and a wireless telephone set, 
respectively, it is to be understood that mobiles 20 and 
30 may be wireless data communications or multimedia 

40 communications devices. 

The operations of wireless visiting network 104 and 
wireless home network 120 and the interactions of their 
elements to implement the principles of the invention 
are better understood when described in conjunction 

45 with a flow diagram for the registration process for one 
of the mobiles, mobile 20, for example. This flow dia- 
gram is shown in FIG. 2 and is described below with ref- 
erence to the elements of FIG. 1. Because visiting 
network 1 04 and home network 1 20 are (for the sake of 

so simplicity) similarly configured, a description of the com- 
ponents of visiting network 104 is provided below with 
reference to equivalent components in home network 
120 indicated in parentheses. 

Also shown in FIG. 1 is Intelligent Peripheral (IP) 53 

55 (63) that is connected to MTSO 50 (60). One of the 
modular components that may be included in IP 53 (63) 
is Voice Response Unit (VRU) 53, which is arranged to 
prompt a caller for specific information by asking ques- 
tions in the form of recorded announcements that are 



BNSDOCID <EP 0788287A2 



5 



EP 0 788 287 A2 



6 



based on a set of modules in a transaction script. Rele- 
vant information collected from a caller in the form of 
Dual Tone Multi-Frequency (DTMF) signals or speech 
input is interpreted by VRU 53 for delivery to Home 
Location Register (HLR 91), as explained below. Voice 
Response Unit 53 (63) may be implemented using, for 
example, vendors' products, such as the Brite system or 
the AT&T Conversant Voice System whose architecture 
and features are described in AT&T Technical Journal . 
Vol. 65, Issue 5, pp. 33-47, Sept./Oct 1986. Also shown 
in FIG. 1 as a modular component of IP 53 (63) is Voice 
Mail (VM) system 54 which is arranged to deliver a 
prompting announcement soliciting a telephone number 
at which a calling party can be reached. Well-known 
voice mail systems include the Octel Communications 
System and the AT&T Audio exchange system whose 
features and functionality are described in US Patent 
Number 4,790,003 issued to G. D. Kepley, et al. on Dec. 
6, 1988 

As is known in the art, the registration process 
allows the identity and the relative position of a mobile in 
an active idle state to be known to a home network, 
such as home network 120, for functions such as a) 
delivery of incoming calls to the wireless set, and b) bill- 
ing for calls initiated or received by the set. The registra- 
tion process is typically initiated when a user powers on 
wireless telephone set 20, as indicated in step 201. 
When visiting wireless network 104 is an analog com- 
munications system that implements, for example, the 
Advanced Mobile Phone Service (AMPS) cellular radio 
standard, mobile 20 determines the frequency of the 
strongest received radio signal to locate the reverse 
control radio channel associated with the nearest base 
station, which may be either base station 36 or 37 
depending on factors such as the strength of signals 
radiated by one of these base stations. As is known in 
the art, the reverse radio control channel is a signaling 
channel that is used by a base station to exchange sig- 
naling information with mobiles in the radio coverage 
area of a base station known as a "cell". 

Once the reverse control radio channel of base sta- 
tion 36, for example, is located by mobile 20, that mobile 
transmits signaling information to base station 36 via 
the identified radio control channel. Signaling informa- 
tion communicated by mobile 20 to one of the base sta- 
tions 36 and 37 for the registration process includes the 
Mobile Identification Number (MIN) and the Electronic 
Serial Number (ESN) of mobile 20 Base stations 36 
and 37 (39, 40) include transceivers and other hardware 
arranged to transfer via the airwaves information 
received from Mobile Telephone Switching Office 
(MTSO) 50 (60) via wired facilities 16 and 17 (14 and 
1 5) respectively. Alternatively, point-to-point microwave 
links may also be used to connect base stations 36, 37 
(39, 40) to MTSO 50 (60). Similarly, information 
received from the mobiles via the airwaves is trans- 
ferred by base stations 36 and 37 (39 and 40) to MTSO 
50 (60) via point-to-point microwave links or land-line 
facilities 16 and 17 (14 and 15) respectively. Hence, 



upon receiving the MIN and ESN pair associated with 
mobile 20, base station 36 typically transmits the 
M IN/ESN information to MTSO 50, as indicated in step 
202. 

5 MTSO 50 (60) is comprised of a set of modular 
hardware and software components designed to admin- 
ister the allocation of radio channels within the visiting 
network 104 (home network 120), and to coordinate 
paging of wireless telephone sets 10 and 30 for calls 

10 destined for those sets. MTSO 50 also coordinates 
hand-off of calls (in progress) from one base station to 
another, as mobile 20 leaves one cell to cross the bor- 
ders of another cell. Although MTSO 50 (60) is shown in 
FIG. 1 as being remote from base stations 36 and 37, 

15 (39 and 40), it is to be understood that MTSO 50 (60) 
may be co-located with one of the base stations 36 and 
37 (39 and 40). 

One of the modular components of MTSO 50 (60) is 
Mobile Switching Center (MSC) 52 (62) which is typi- 

20 cally a processor-controlled software-driven switching 
system arranged to provide seamless communications 
paths by bridging radio channels and wired channels for 
calls routed over visiting wireless network 104 (home 
network 120) and land-line network 70 Of particular 

25 significance is the role played by MSC 51 (61) in the 
registration process mentioned above. Specifically, 
when MSC 51 (61) receives from base station 36 a reg- 
istration request message which includes the MIN and 
ESN pair of mobile 30, MSC 51 proceeds to send that 

30 message to VLR 52, which determines based on the 
digits of the received MIN, that mobile 30 is a roaming 
mobile. VLR 52 is a database facility that is used to 
retrieve information for handling communications serv- 
ices requests from a roaming mobile. VLR 52 uses the 

35 MIN and ESN pair included in the REGNOT message to 
identify Home Location Register (HLR) HLR 66 as the 
home location register of mobile 30. Thereafter, VLR 52 
sends a Registration Notification (REGNOT) message 
to Home Location Register (HLR) HLR 66. As is known 

to in the art, an HLR is a database facility that stores sub- 
scriber information associated with a mobile. Informa- 
tion stored for a subscriber includes the MIN/ESN pair 
of the subscriber's mobile end-user device, and the sub- 
scriber's profile which identifies the set of features, 

45 capabilities and/or operations restrictions associated 
with the subscriber for roaming and local communica- 
tions services 

FIG. 4 shows an illustrative table that stores infor- 
mation associated with a profile of a wireless sub- 
so scriber. The fields grouped under the header 
"subscribed features" indicate the different communica- 
tions services features that may be subscribed to by a 
user. Although the table of FIG. 4 shows only the call 
waiting, call forwarding. 3-way calling and international 

55 calling features, it is to be understood that other features 
may also be available. Information associated with the 
respective date/time within which a subscriber can roam 
in one or more particular location areas is shown in the 
table of FIG. 4 under the "Roaming Restriction per MSC 



4 



7 



EP 0 788 287 A2 



(RRM)*' group of fields. As is well known in the art, a 
location area is a wireless geographical area served by 
an MSC. Thus, the unique identification number of an 
MSC called "MSCID" identifies not only the MSC but 
also the location area served by the MSC. The RRM s 
group of fields includes a RRM List field which is a 
pointer identifying a set of location areas (illustrated in 
the table of FIG. 5 ) in which roaming is authorized only 
when certain conditions are met. For example, the sub- 
scriber whose profile is shown in the table of FIG. 4 can 7£ > 
exercise roaming privileges in location areas associated 
with MSC IDs 28. 15 and 33 only after the date indicated 
in the time specification field. In actual application of the 
principles of the invention, the date in the time specifica- 
tion field may be entered in YYDDD format, where YY ;5 
represents the last two digits of the year, and 1 < DDD < 
366. As is well known in the art, the YYDDD format 
allows easier comparison of the date stored in the time 
specification field ( t}) with current date ( to) It is worth 
noting that a subscriber is free to roam in a location area 20 
that is not identified by a pointer in the RRM list in the 
subscriber's profile. Advantageously, the tables of FIGs 
4 and 5 provide great flexibility in designing a profile for 
a subscriber since a profile may have 20 entries (or 
more) in the RRM group of fields, and any combination 25 
of 256 (or more) different MSCIDs represented in those 
entries. 

Also shown in the table of FIG. 4 is the roaming 
characteristic associated with a particular M IN/ESN 
pair. A subscriber who is a frequent roamer is given a 30 
roaming characteristic value of "1 " while a value of "0" in 
the roaming characteristic field indicates that a sub- 
scriber has no (or very little) roaming history. Alterna- 
tively, values ranging from 0 to 9 may be used to identify 
the roaming characteristics of a subscriber. In the latter 35 
case values above a threshold of 4 or 5, for example, 
would indicate that a subscriber is a frequent roamer. 

Referring back to FIG. 2, once VLR 52, in step 203, 
identifies HLR 66 as the home location register of 
mobile 30, VLR 52 transmits a "registration invoke" sig- 40 
naling message to HLR 66, in step 204, to request the 
subscriber profile stored in HLR 66. The "registration 
invoke" signaling message includes the MSCID of MSC 
51 and the MIN/ESN pair. Upon receiving the "registra- 
tion invoke" signaling message, HLR 66 uses the 45 
MIN/ESN pair of mobile 30 to retrieve the subscriber's 
profile associated with that mobile, as indicated in step 
205. Thereafter, HLR 66 determines, in step 206, 
whether roaming privileges are restricted for the 
received MIN/ESN pair in the roaming area from which so 
the registration request originated. This is achieved in a 
two-step process. In a first step, the pointers repre- 
sented by the contents of the RRM list field in the sub- 
scriber's profile are used to retrieve the MSCIDs 
illustrated n FIG. 5. In a second step, the MSCID 55 
included in the "registration invoke" message is com- 
pared to each one of the retrieved MSCIDs. If no match 
is found, HLR 66 proceeds with the registration proce- 
dure in a conventional manner, as indicated in step 207. 



If a match is found, however, HLR 66 compares the cur- 
rent date with the date indicated in the time specification 
field in the profile for the RRM list number in question. If 
the content in the time specification field indicates a 
later date than the current date, HLR 66 proceeds with 
the registration procedure as follows. 

According to another aspect of the invention, when 
the roaming area in question is restricted, as indicated 
by an earlier date than the current date in the time spec- 
ification field, HLR 66 determines in step 208 whether 
the subscriber associated with the MIN/ESN pair of 
mobile 20 is a frequent roamer. This is indicated, in this 
illustrative example, by a value of "1" in the roaming 
characteristic field of the profile for a frequent roamer 
and a value of "0" for an infrequent roamer. What is con- 
sidered a frequent roamer is implementation-depend- 
ent. For example, a service provider may consider a 
subscriber who roams three times (or more) a month a 
frequent roamer, while another service provider may 
label a frequent roamer only subscribers who roam 10 
times (or more) a month. Other service providers may 
prefer to use a longer or shorter time period per number 
of roaming occurrences. If the subscriber is not a fre- 
quent roamer, as determined in step 208, a denial of 
registration message is returned to the VLR, as shown 
in step 208. For a frequent roamer, HLR 66 sends a sig- 
naling message to VLR 52 to instruct the latter to inter- 
cept any outgoing call initiated by mobile 20 and to 
complete the call instead to either a live operator (not 
shown) or to Voice Processing System 63. Upon receiv- 
ing the call interception signaling message from HLR 
91 , VLR 52 creates a record in its data structure for the 
MIN/ESN pair of mobile 20. The record will include the 
telephone number of Voice Processing System 63 (or 
the operator) to which intercepted calls should be for- 
warded. 

FIG. 3 shows illustrative processing instructions 
executed by some of the elements of FIG. 1 to complete 
wireless calls initiated from mobile 20 when the call 
interception feature has been activated as part of the 
registration process. When a user at mobile 20 initiates 
a wireless call, as shown in step 301, the call is received 
by base station 36 which forwards the MIN/ESN and the 
dialed number to MSC 51 via line 16. MSC 51 queries 
VLR 52 to determine how to complete the call. Upon 
determining that the call interception feature is activated 
for the MIN/ESN pair associated with the call, VLR 52 
instructs MSC 51 to forward the call and the dialed 
number to Voice Response Unit 65, as illustrated in step 
302. 

Voice Response Unit 55, in step 303, uses 
recorded announcements stored therein to prompt the 
caller for personal authentication information Ques- 
tions posed to a caller may include, for example, the 
subscriber's social security number, date of birth or 
other information that can be entered as digits on a dial 
pad. When Voice Response Unit 55 is equipped with a 
speech recognition system, additional information, such 
as billing address or mother's maiden name, may also 



5 



9 



EP 0 788 287 A2 



10 



be collected as authentication information from the 
caller Voice Response Unit 55 proceeds to transfer the 
collected information to HLR 66. for validation therein 
This may be accomplished, for example, by comparing 
the information collected from the caller to data stored in 5 
the personal information field in the subscriber's profile 
of FIG. 4. If a match is found, the information provided 
by the caller is considered valid. Otherwise, the informa- 
tion received by Voice Response Unit 55 from the caller 
is considered invalid. When the received information is w 
invalid, as determined in step 304, the call is terminated, 
as indicated in step 305. Alternatively, law enforcement 
authorities may be alerted for appropriate action. 

If the received authentication information is valid, 
Voice Response Unit 55, in step 306, prompts the caller is 
for information which includes his or her duration of stay 
in the roaming area. Thereafter, Voice Response Unit 
55, in step 307, completes the call to the destination 
number provided by the caller. This is accomplished, for 
example, by Voice Response Unit 55 instructing MSC zo 
61 to establish a connection to the destination number 
provided by the caller and bridging the first leg of the 
connection (i.e., from the caller to Voice Response Unit 
55) to the second leg of the connection (i.e., from MSC 
61 to the destination number provided by the caller) 25 

After completion of the call, Voice Response Unit 
55 transfers the duration of stay information collected 
from the caller to HLR 66. Upon receiving that informa- 
tion, HLR 66, in step 308 enters that information in the 
time specification field of FIG. 5 to update the sub- 30 
scriber's profile. Thereafter, HLR 66, in step 309, sends 
a signaling message to VLR 52 to indicate that the call 
interception feature has been deactivated. 

Although MSC 51 (61), HLR 56 (66) and VLR 52 
(62) are shown in FIG. 1 as distinct physical compo- 35 
nents, it is to be understood that those components may 
be integrated in one networking entity that performs the 
individual functions carried out by each one of those 
components. 

According to another aspect of the invention, the to 
time specification field may be populated by a caller 
dialing a telephone number, such as a toll-free number 
that is associated with Voice Response Unit 55 to popu- 
late the roaming restriction period field for one or more 
selected roaming areas. This method may also be used 45 
to select a new roaming area. Population of the roaming 
restriction field using this method involves Voice 
Response Unit 55 prompting a caller for authentication 
information before the caller is authorized to select a 
roaming area or provide time specification data for a so 
roaming area. At the end of the call, Voice Response 
Unit 55 transfers the collected information to HLR 66 for 
storage in the tables of FIG. 4 and 5. 

The foregoing is to be construed as only being an 
illustrative embodiment of this invention. Persons skilled 55 
in the art can easily conceive of alternative arrange- 
ments providing functionality similar to this embodiment 
without any deviation from the fundamental principles or 
the scope of this invention. 



Claims 

1 . A method of processing a communications service 
request from a mobile end-user device, said 
method comprising the steps of: 

receiving at a wireless communications system 
a communications service request initiated by 
a mobile end-user device, said request includ- 
ing i) identification information associated with 
said mobile end-user device, and ii) information 
indicative of a roaming area from which said 
request was initiated; 

retrieving a profile associated with said mobile 
end-user device based on least a portion of 
said identification information; and 

denying said communications service request 
to said mobile end-user device when said 
request is received within a roaming restriction 
time window identified in said profile for said 
roaming area. 

2. The method of claim 1 wherein said identification 
information associated with said mobile end-user 
device includes an electronic serial number. 

3. The method of claim 1 wherein said identification 
information associated with said mobile end-user 
device includes a mobile identification number. 

4. A method of operating a network providing wireless 
communications services, said method comprising 
the steps of: 

storing in a memory data structures that asso- 
ciate data related to i) identification information 
for at least one wireless subscriber, and ii) at 
least one selected roaming area from which 
said at least one wireless subscriber is prohib- 
ited from initiating wireless calls within a 
selected period of time; 

denying a connection request when said con- 
nection request is a) received in conjunction 
with identification information that matches 
said identification information stored in said 
memory b) initiated from said at least one 
selected roaming area, and within said 
selected period of time. 

5. A communications system for processing registra- 
tion requests for wireless calls, said system com- 
prising: 

a computer's storage area containing data 
structures that associate data related to i) iden- 
tification information of at least one mobile end- 



6 



11 



EP 0 788 287 A2 



12 



user device ii) at least one selected roaming 
area in which wireless calls that are initiated 
therefrom within a selected time window with 
said at least one mobile end-user device, are 
prohibited from being completed; and 5 

a processor that a) analyzes signaling informa- 
tion received in connection with a registration 
request for a wireless call to inquire whether at 
least a portion of said signaling information 10 
matches said identification information and 
said at least one selected roaming area stored 
in said computer's storage area, and b) in 
response to a positive answer to said inquiry, 
denies said registration request when said reg- 15 
istration request is initiated within said selected 
period of time. 

The system of claim 5 wherein said identification 
information includes an electronic serial number for 20 
said at least one mobile end-user device of said at 
least one wireless subscriber. 

The system of claim 5 wherein said identification 
information includes an includes a mobile identifica- 25 
tion number. 

A wireless communications system comprising: 

a switching system that receives at time t 0 a 30 
communications service request initiated by a 
mobile end-user device for a wireless call, said 
request including i) identification information 
associated with said mobile end-user device 
and ii) a roaming area from which said request 35 
for registration originated; and 
a processor which receives said identification 
information and instructs said switching system 
to deny said communications service request 
from said mobile end-user device when said 40 
processor determines that at least a portion of 
said received identification information 
matches an entry in a profile that prohibits hon- 
oring said communications service request to 
said mobile end-user device for calls initiated 45 
by said mobile end-user device from said roam- 
ing area and before a period of time t, where t, 
>t 0 . 

A method of processing a wireless call initiated so 
from a mobile end-user device, said method com- 
prising the steps of: 

receiving at a wireless communications switch 
a communications service request for said 55 
wireless call initiated by a caller with a mobile 
end-user device, said request including i) iden- 
tification information associated with said 
mobile end-user device, and ii) a roaming area 



from which said request was initiated and iii) a 
called party number; 

retrieving a profile associated with said mobile 
end-user device using at least a portion of said 
identification information as a search key; 

ascertaining from said profile i) roaming char- 
acteristics of a subscriber associated with said 
mobile end-user device and ii) restrictions on 
completion of calls initiated with said mobile 
end-user device from said roaming area; and 

redirecting said wireless call to an operator 
based on said roaming characteristics associ- 
ated with said subscriber when said restrictions 
are in effect. 

10. The method of claim 9 wherein said wireless call is 
redirected to said operator only when said roaming 
characteristics in said profile indicate that said sub- 
scriber of said mobile end-user device is a frequent 
roamer. 

11. The method of claim 9 further comprising the steps 

of: 

prompting said caller for authentication infor- 
mation; and 

completing said wireless call to said called 
party number only when authentication infor- 
mation provided by said caller in response to 
said prompt is valid. 

12. The method of claim 9 further comprising the step 
of: 

prompting said caller for authentication infor- 
mation; and 

terminating said call when said authentication 
information provided by said caller in response 
to said prompt is invalid. 

13. The method of claim 9 further comprising the steps 
of 

prompting said caller for authentication infor- 
mation and data indicative of a duration of stay 
period in said roaming area; 

completing said wireless call to said called 
party number only when authentication infor- 
mation provided by said caller in response to 
said prompt is valid; and 

authorizing completion of subsequent wireless 
calls to their intended destination without call 
redirection to said operator when said subse- 



13 



EP 0 788 287 A2 



14 



quent wireless calls are initiated from said 
roaming area by said mobile end-user device 
and within said duration of stay period in said 
roaming area. 

5 

1 4. The method of claim 1 3 further comprising the step 
of 

deactivating said call completion authorization 
for said mobile end-user device after said dura- to 
tion of stay period has expired. 

1 5. A system for processing a communications service 
request from a mobile end-user device, said system 
comprising: is 

a wireless communications switching system 
which receives from a mobile end-user device 
a communications service request initiated by 
a caller to complete a wireless call, said so 
request including i) identification information 
associated with said mobile end-user device, ii) 
a roaming area from which said request was 
initiated and iii) a called party number; 

a database from which a profile associated with 
said mobile end-user device is retrieved based 
on least a portion of said identification informa- 
tion, said profile being retrieved to determine 
therefrom i) roaming characteristics of a sub- so 
scriber associated with said mobile end-user 
device and ii) restrictions on completion of calls 
initiated with said mobile end-user device from 
said roaming area; and 

35 

a processor which redirects said wireless call 
to an operator based on said roaming charac- 
teristics associated with said subscriber when 
said restrictions are in effect. 

40 

16. The system of claim 15 wherein said processor 
redirects said call to said operator only when said 
roaming characteristics in said profile indicate that 
said subscriber is a frequent roamer. 

45 

17. The method of claim 14 further comprising 



mation provided by said caller in response to 
said prompt is invalid. 

19. The method of claim 14 further comprising 

a voice processing system which a) prompts 
said caller for authentication information and 
data indicative of a duration of stay period in 
said roaming area b) directs said processor to 
complete said call to said called party when 
authentication information provided by said 
caller in response to said prompt is valid, and c) 
forwards said duration of stay period data to 
said processor to allow said processor to 
authorize completion of subsequent wireless 
calls to their intended destination without call 
redirection to said operator when said subse- 
quent wireless calls are initiated from said 
roaming area by said mobile end-user device 
and within said duration of stay period in said 
roaming area. 



a voice processing system which prompts said 
caller for authentication information and directs 
said processor to complete said call to said so 
called party when authentication information 
provided by said caller in response to said 
prompt is valid. 

18. The method of claim 14 further comprising ss 

a voice processing system which prompts said 
caller for authentication information and termi- 
nates said call when said authentication infor- 



8 



EP 0 788 287 A2 




EP 0 788 287 A2 



FIG. 2 



USER INITIATES REGISTRATION PROCEDURE 
BY POWERING ON MOBILE 



-201 



BASE STATION FORWARDS IDENTIFICATION 
INFORMATION OF MOBILE TO MSC 



MSC FORWARDS IDENTIFICATION 
INFORMATION TO VLR WHICH USES THE - 
IDENTIFICATION INFORMATION TO ASCERTAIN 
THE IDENTITY OF THE HLR FOR THE MOBILE 



-202 



-203 



207 



VLR TRANSMITS A "REGISTRATION INVOKE" 
MESSAGE TO THE IDENTIFIED HOME 
LOCATION REGISTER 



T 



HOME LOCATION REGISTER RETRIEVES 
PROFILE FOR MIN/ESN PAIR 



COMPLETE REGISTRATION 

PROCEDURE IN A 
CONVENTIONAL MANNER 



^ROAMING AREA RESTRICTED f > 
| YES 

? Q fi X FREQUENT ROAMER ? > ^ 

Us 



209- 



SEND INSTRUCTIONS TO MSC 
TO INTERCEPT OUTGOING CALL 
FROM MOBILE AND FORWARD 
THAT CALL TO AN OPERATOR 
AND TO ALLOW REGISTRATION 



-204 



-205 



210 



RETURN DENIAL 
OF SERVICE 
MESSAGE TO 
THE VLR 



( END ) 



10 



EP 0 788 287 A2 



FIG. 3 



I CALL IS RECEIVED FROM MOBILE k^ 301 
I 

[C '. IS WARDED TO [RA] 



OPERATOR PROMPTS CALLER FOR 
PERSONAL AUTHENTICATION INFORMATION 



X 



-303 



RECEIVED 
INFORMATION 
V ALID ? 
{ YES 



304 
NO 



-305 



[[ RMINATE CA LL | 



CALLER IS PROMPTED FOR 
DURATION OF STAY IN ROAMING AR EA 

1 



COMPLETE CALL TO DESTINATION 
NUMBER PROVIDED BY CALLER 



UPDATE ROAMING VALIDATION TABLE 



NOTIFY VLR THAT CALL INTERCEPTION 
FEATURE HAS BEEN DEACTIVATED 



-306 

-307 
^308 
309 



( END ) 



11 



EP 0 788 287 A2 




12 



EP 0 788 287 A2 



FIG. 5 



RRM LIST #1 


MSCID = 


28 


MSCID = 


15 




MSCID = 


33 



13 



(88) Date of publication A3: 

21.07.1999 Bulletin 1999/29 



(43) Date of publication A2: 

06.08.1997 Bulletin 1997/32 



(21) Application number: 97101730.6 

(22) Date of filing: 04.02.1997 



Europaisches Patentamt 
European Patent Office 
Office europeen des brevets (1 1 ) EP 0 788 287 A3 

EUROPEAN PATENT APPLICATION 

(51) int. Cl. 6 : H04Q7/38, H04Q 7/22 



(84) Designated Contracting States: 


(72) Inventors: 


DE FR GB IT 


• Amin, Umesh J. 




Redmond, Washington 98052 (US) 


(30) Priority: 05.02.1996 US 597066 


• Redden, Michael 




Greenwich, Connecticut 06831 (US) 


(71) Applicant: 


AT&T WIRELESS SERVICES, INC. 


(74) Representative: 


Kirkland, WA 98033 (US) 


R.A. KUHNEN & P.A. WACKER 




Alois-Steinecker-Strasse 22 




85354 Freising (DE) 



(54) Roaming authorization system 

(57) A roaming restriction system permits a wireless 
carrier or a subscriber to set a profile that identifies a 
chosen time window within which the subscriber's wire- 
less calls that are originated from one or more selected 
roaming areas, are not allowed to be completed, while 
calls that are initiated either from authorized roaming 
FIG. 1 



areas or outside the chosen time window are allowed to 
be completed. The roaming restriction system allows a 
wireless carrier to either suspend or grant roaming priv- 
ileges for a given subscriber within one or more location 
areas, and for a particular time window. 



CO 
< 

co 
eg 

CO 




CL 
LU 



3d bt xe'ox (UK) Business Services . 



EP 0 788 287 A3 



European Patent 
Office 



EUROPEAN SEARCH REPORT 



EP 97 10 1730 



DOCUMENTS CONSIDERED TO BE RELEVANT 



WO 93 11646 A (ELECTRONIC DATA SYST CORP) 
10 June 1993 

* page 3, line 27 - page 4, line 25 * 

US 5 335 278 A (MATCHETT NOEL D ET AL) 
2 August 1994 

* column 3, line 35 - column 4, line 39 * 



1,4,5.1 
9,15 



1,4,5,1 
9,15 



H04Q7/38 
H04Q7/22 



;n drawn up tor all el; 



CATEGORY OF CITED DOCUMENTS 



2 



EP 0 788 287 A3 



ANNEX TO THE EUROPEAN SEARCH REPORT 
ON EUROPEAN PATENT APPLICATION NO. 



EP 97 10 1730 



This annex lists the patent family m 
I he memDers are as contained in tr 
The European Patent Office is in n< 



in the above-mentioned European search report, 
are merely given for the purpose of in 



i For more details about this annex . see Off cial Jc 



of the European Patent Office, f\