Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
1998-09-29
2001-04-10
Nguyen, Lee (Department: 2683)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S457000, C455S550100, C455S558000, C455S410000, C342S457000
Reexamination Certificate
active
06216007
ABSTRACT:
BACKGROUND OF THE PRESENT INVENTION
1. Field of the Invention
The present invention relates generally to telecommunications systems and methods for determining the location of a mobile terminal within a cellular network, and specifically to preventing the alteration of location information for mobile terminal-based location calculation methods.
2. Background and Objects of the Present Invention
Cellular telecommunications is one of the fastest growing and most demanding telecommunications applications ever. Today it represents a large and continuously increasing percentage of all new telephone subscriptions around the world. A standardization group, European Telecommunications Standards Institute (ETSI), was established in 1982 to formulate the specifications for the Global System for Mobile Communication (GSM) digital mobile cellular radio system.
With reference now to
FIG. 1
of the drawings, there is illustrated a GSM Public Land Mobile Network (PLMN), such as cellular network
10
, which in turn is composed of a plurality of areas
12
, each with a Mobile Switching Center (MSC)
14
and an integrated Visitor Location Register (VLR)
16
therein. The MSC/VLR areas
12
, in turn, include a plurality of Location Areas (LA)
18
, which are defined as that part of a given MSC/VLR area
12
in which a mobile station (MS) (terminal)
20
may move freely without having to send update location information to the MSC/VLR area
12
that controls the LA
18
. Each Location Area
18
is divided into a number of cells
22
.
Mobile Station (MS)
20
is the physical equipment, e.g., a car phone or other portable phone, used by mobile subscribers to communicate with the cellular network
10
, each other, and users outside the subscribed network, both wireline and wireless. The MS
20
may also include a Subscriber Identity Module (SIM) card
13
, or other memory, which provides storage of subscriber related information, such as a subscriber authentication key, temporary network data, and service related data (e.g. language preference).
The MSC
14
is in communication with at least one Base Station Controller (BSC)
23
, which, in turn, is in contact with at least one Base Transceiver Station (BTS)
24
. The BTS is the physical equipment, illustrated for simplicity as a radio tower, that provides radio coverage to the cell
22
for which it is responsible. It should be understood that the BSC
23
may be connected to several BTS's
24
, and may be implemented as a stand-alone node or integrated with the MSC
14
. In either event, the BSC
23
and BTS
24
components, as a whole, are generally referred to as a Base Station System (BSS)
25
.
With further reference to
FIG. 1
, the PLMN Service Area or cellular network
10
includes a Home Location Register (HLR)
26
, which is a database maintaining all subscriber information, e.g., user profiles, current location information, International Mobile Subscriber Identity (IMSI) numbers, and other administrative information, for subscribers registered within that PLMN
10
. The HLR
26
may be co-located with a given MSC
14
, integrated with the MSC
14
, or alternatively can service multiple MSCs
14
, the latter of which is illustrated in FIG.
1
.
The VLR
16
is a database containing information about all of the MS's
20
currently located within the MSC/VLR area
12
. If an MS
20
roams into a new MSC/VLR area
12
, the VLR
16
connected to that MSC
14
requests data about that MS
20
from the HLR database
26
(simultaneously informing the HLR
26
about the current location of the MS
20
). Accordingly, if the user of the MS
20
then wants to make a call, the local VLR
16
will have the requisite identification information without having to reinterrogate the HLR
26
. In the aforedescribed manner, the VLR and HLR databases
16
and
26
, respectively, contain various subscriber information associated with a given MS
20
.
Determining the geographical position of a MS
20
within a cellular network
10
has recently become important for a wide range of applications. For example, positioning services may be used by transport and taxi companies to determine the location of their vehicles. In addition, for emergency calls, e.g., 911 calls, the exact location of the mobile terminal
20
may be extremely important to the outcome of the emergency situation. Furthermore, positioning services can be used to determine the location of a stolen car, for the detection of home zone calls, which are charged at a lower rate, for the detection of hot spots for micro cells, or for the subscriber to determine, for example, the nearest gas station, restaurant, or hospital, e.g., “Where am I” service.
MS-based location calculation methods have recently been developed whereby BTS
24
coordinates and other location information are transmitted to the MS
20
for calculation of the location of the MS
20
. The MS
20
can then forward its location to a network location application that requested the positioning of the MS
20
or can use its determined location along with internal location applications to display the location information to the mobile subscriber.
For example, the MS
20
can have a Global Positioning System (GPS) receiver built into it, which is used to collect location information in order to allow the MS
200
to calculate its location. In addition, the MS
20
can collect positioning data based on the Observed Time Difference (OTD) between the time a BTS
24
sends out a signal and the time the MS
20
receives the signal. This time difference information can then be used by the MS
20
for calculation of the location of the MS
20
.
By using Enhanced-OTD or GPS positioning methods with MS-based location calculation, it becomes unnecessary to have active two-way communication between the MS
20
and the network
14
, which increases the signaling capacity of the network
14
, and allows the MS
20
to perform location calculation while the MS
20
is in idle-mode. The implementation of MS-based location calculation is therefore expected to trigger a number of additional location applications, such as home zone charging, in which the price for using the voice or signaling channels can be dependent on the geographical location of the MS
20
. However, when the MS
20
is responsible for calculating its position rather than the network, the system becomes volatile to fraud. For example, a mobile subscriber may be able to alter the real calculated location in order to apply a different (cheaper) tariff when using the voice or signaling channels.
It is, therefore, an object of the present invention to prevent the alteration of location information by the mobile subscriber when utilizing mobile terminal-based location calculation mechanisms.
SUMMARY OF THE INVENTION
The present invention is directed to telecommunications systems and methods for minimizing the chances of mobile subscriber fraudulently calculating the location of an associated mobile terminal when the positioning measurements and location calculation are performed by the mobile terminal. Mobile-based E-OTD (or GPS) location calculation methods allow the mobile terminal to calculate its own location in idle or dedicated mode based upon positioning measurements obtained by the mobile terminal, additional information supplied by the network and a location calculation function within the mobile terminal. Specifically, the location calculation can be carried out by utilizing a Positioning Measurement Module (PMM) within the mobile terminal for performing the positioning measurements and a Location Calculation Module (LCM) within the mobile terminal for converting the positioning measurements to location information. In order to prevent tampering with the location information, the PMM, which will always be embedded on the mobile terminal, is separated from the LCM by including the LCM on a smart IC card, such as a SIM card, within the mobile terminal. The smart IC card can contain a Read Only Memory (ROM) for storing application specific data, such as BTS coordinates and
Boltz David
Havinis Theodore
Ericsson Inc.
Jenkens & Gilchrist P.C.
Nguyen Lee
Nguyen Simon
LandOfFree
Prevention of alteration of location information for... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Prevention of alteration of location information for..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Prevention of alteration of location information for... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2490269