Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
1999-03-18
2001-10-30
Vo, Nguyen T. (Department: 2682)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S432300, C455S414200
Reexamination Certificate
active
06311069
ABSTRACT:
BACKGROUND OF THE PRESENT INVENTION
Field of the Invention
The present invention relates generally to telecommunications systems and methods for positioning a mobile subscriber within a cellular network, and specifically to alerting a mobile subscriber that a request for a positioning of that mobile subscriber has been received.
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
14
provides a circuit switched connection of speech and signaling information between a Mobile Station (MS)
20
and the PLMN
10
. 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 the MS
20
may move freely without having to send update location information to the MSC
14
that controls the LA
18
. Each LA
18
is divided into a number of cells
22
. The 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 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
.
Determining the geographical position of an MS
20
within a cellular network
10
has recently become important for a wide range of applications. For example, location services (LCS) 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 MS
20
may be extremely important to the outcome of the emergency situation. Furthermore, LCS 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.
As can be seen in
FIG. 2
of the drawings, upon a network positioning request, the MSC
14
obtains, from the serving BTS
24
and BSC
23
, a Timing Advance (TA) value, which corresponds to the amount of time in advance that the MS
20
must send a message in order for the serving BTS
24
to receive it in the time slot allocated to that MS
20
. The TA value, in turn, provides location information regarding the MS
20
location. This is due to the fact that when a message is sent from the MS
20
to the BTS
24
, there is a propagation delay, which depends upon the distance between the MS
20
and the BTS
24
. The TA values are expressed in bit periods, and can range from 0 to 63, with each bit period corresponding to approximately 550 meters between the MS
20
and the BTS
24
.
This TA value is forwarded to a Serving Mobile Location Center (SMLC)
270
for use in assisting the calculation of the geographical location of the MS
20
.
It should be noted that the SMLC
270
can use a number of different positioning mechanisms, including, but not limited to, Time of Arrival (TOA), Enhanced Observed Time Difference (E-OTD) and Global Positioning System (GPS). After the SMLC
270
calculates the MS
20
location, this location can be sent to a Location Application (LA)
280
that requested the positioning. It should be noted that the requesting LA
280
could be located within the MS
20
itself, within the MSC
14
or could be an external node, such as an Intelligent Network (IN) node. If the LA
280
is not within the MS
20
or within the MSC
14
, the location information is sent to the requesting LA
280
via the MSC
14
and a Gateway Mobile Location Center (GMLC)
290
.
Existing technology can provide mobile subscribers with the ability to prevent LAs
280
from positioning them in order to protect their privacy. However, in some cases, it is necessary for the specific LA
280
to position the MS
20
regardless of the privacy settings of the particular subscriber. For example, when the LA
280
is an emergency center or a law enforcement agency, the community interest in positioning the MS
20
outweighs the subscriber's need for privacy. In this case, the privacy settings of the subscriber will need to be overridden in order for the emergency center or law enforcement agency to position the MS
20
. In addition, LAs
280
may need to have the ability to override other location settings established by the subscriber. Thus, a Privacy Override Indicator (POI) (not shown) can be provided by network operators to allow an LA
280
to override the subscriber's privacy settings in order to obtain the location of the mobile subscriber.
The POI is typically assigned on an individual LA
280
basis by the GMLC
290
during the registration of the LA
280
at the GMLC
290
associated with the PLMN
10
that the LA
280
is located in. Normally, commercial-type LA's
280
are not allowed to override the subscriber's privacy settings, e.g., the assigned value of the POI is “not override.” However, certain specific LA's
280
, such as law enforcement or E-911, which must be capable of positioning a subscriber regardless of the subscriber's privacy settings, can be assigned a POI with the value “allowed to override subscriber's privacy settings.” It should be noted that when the subscriber is roaming, law enforcement LA's
280
will need, in addition to the POI with the value “allowed to override subscriber's privacy settings,” a court order in order to be able to override the mobile subscriber's privacy settings.
Furthermore, even though a mobile subscriber has established privacy settings, the mobile subscriber may want to allow certain other subscribers or LAs
280
to have the ability to position the mobile subscriber regardless of the mobile subscriber's privacy settings. Such other subscribers could be, for example, the mobile subscriber's family or member(s) of a particular group, such as, e.g., in the case where the subscriber is an employee of a taxi company, the operations center or the mobile subscriber's manager. For those cases, the mobile subscriber may also want to put limits on the ability of those other subscribers or LA's
280
to position him or her. For example, the mobile su
Boltz David
Havinis Theodore
Ericsson Inc.
Jenkens & Gilchrist P.C.
Moore James K
Vo Nguyen T.
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