U.S. patent application number 13/973317 was filed with the patent office on 2013-12-19 for method of determining a location of a mobile device and method of managing a list for use in such a method.
This patent application is currently assigned to Koninklijke KPN N.V.. The applicant listed for this patent is Koninklijke KPN N.V., Nederlandse Organisatie voor Toegepast- Natuurwetenschappelijk Onderzoek TNO. Invention is credited to Antonius Hendrikus Johannes Norp, Franklin Selgert.
Application Number | 20130337833 13/973317 |
Document ID | / |
Family ID | 40625201 |
Filed Date | 2013-12-19 |
United States Patent
Application |
20130337833 |
Kind Code |
A1 |
Selgert; Franklin ; et
al. |
December 19, 2013 |
Method of Determining A Location Of A Mobile Device And Method Of
Managing A List For Use In Such A Method
Abstract
Methods of determining a location of a mobile device in a first
communication network are presented. The mobile device is in
communication with a cellular base station in a second
communication network. First, access points within the first
communication network are detected with the mobile device. Then,
one or more of the detected access points is selected based on
information provided by the cellular base station. Finally, the
location of the mobile device is determined based on the selected
access points.
Inventors: |
Selgert; Franklin; (Berkel
en Rodenrijs, NL) ; Norp; Antonius Hendrikus Johannes;
(The Hague, NL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nederlandse Organisatie voor Toegepast- Natuurwetenschappelijk
Onderzoek TNO
Koninklijke KPN N.V. |
Delft
The Hague |
|
NL
NL |
|
|
Assignee: |
Koninklijke KPN N.V.
The Hague
NL
Nederlandse Organisatie voor Toegepast- Natuurwetenschappelijk
Onderzoek TNO
Delft
NL
|
Family ID: |
40625201 |
Appl. No.: |
13/973317 |
Filed: |
August 22, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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12639758 |
Dec 16, 2009 |
|
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13973317 |
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Current U.S.
Class: |
455/456.1 |
Current CPC
Class: |
H04W 48/08 20130101;
H04W 64/003 20130101; H04W 64/00 20130101 |
Class at
Publication: |
455/456.1 |
International
Class: |
H04W 64/00 20060101
H04W064/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 18, 2008 |
EP |
08021968.6 |
Claims
1. A method of determining a location of a mobile device (1, 40) in
a first communication network, the mobile device being in
communication with a cellular base station (3, 3a, 3b, 50) in a
second communication network, the method comprising: detecting
access points within the first communication network with said
mobile device; selecting one or more of the detected access points
based on information provided by the cellular base station; and
determining the location of the mobile device based on the selected
access points.
2. The method of claim 1, wherein said information provided by the
cellular base station comprises records regarding access points
within the first communication network that are indicated as being
located within a coverage area of the cellular base station.
3. The method of claim 2, wherein said selecting comprises
excluding detected access points for which no record is present in
said list.
4. The method of claim 2, wherein said access point records
comprise information representative of the position of the
respective access points.
5. The method of claim 2, wherein said access point records
comprise information representative of the identity of the
respective access points.
6. The method of claim 1, wherein said detecting comprises
determining a position of a detected access point.
7. The method of claim 1, wherein said detecting comprises
determining an identity of a detected access point.
8. The method of claim 1, wherein the location of the mobile device
is determined based on information representative of the position
of the selected access points.
9. The method of claim 2, wherein said list is provided in response
to sending a request towards the cellular base station.
10. The method of claim 2, wherein said list is provided via a
broadcast channel.
11. The method of claim 1, wherein a nominal coverage area of the
cellular base station in the second communication network is larger
than a nominal coverage area of an access point within said first
communication network.
12. The method of claim 1, wherein the method further comprises
reporting to the cellular base station in the second communication
network which access points in the first communication network have
been detected.
13. A mobile device (1, 40) arranged to be part of a first
communication network and a second communication network, the
mobile device comprising: a receiver (47) for receiving data from
one or more access points in the first communication network and/or
the second communication network; a transmitter (49) for
transmitting data towards one or more access points in the first
communication network and/or the second communication network; a
memory (43) for storing data; a processor (41) for processing data
received via said receiver and/or stored in said memory; wherein
the mobile device is arranged to determine a location of the mobile
device in the first communication network.
14. A method of managing a list for use in a cellular base station
(3, 3a, 3b, 50) within a second communication network, the list
comprising records regarding access points within a first
communication network that are indicated as being located within a
coverage area of the base station, the method comprising: receiving
a message from an access point within the first communication
network regarding its position; checking whether the position of
the access point is located within the coverage area; updating the
list if said position is located within the coverage area.
15. The method of claim 14, wherein access point records comprise
information representative of the identity of the respective cells,
and wherein the updating includes adding an access point record if
the information representative of the identity of the respective
access point is not present in the list.
16. The method of claim 15, wherein an access point record further
comprises information representative of the position of the access
point, and wherein the updating further includes amending an access
point record if the information representative of the identity of
the respective access point is present in the list, but the
information representative of the position of the access point in
the stored access point record is different from the information
representative of the position of the access point in the
message.
17. The method of claim 14, wherein said updating only occurs if
one or more mobile devices (1, 40) have reported that the access
point has been detected.
18. The method of claim 14, wherein said message is received via a
communication interface within said second communication
network.
19. The method of claim 14, wherein said message is received via a
fixed network.
20. A cellular base station (3, 3a, 3b, 50) comprising: a receiver
(57) for receiving data from one or more access points in the first
communication network and/or the second communication network; a
transmitter (59) for transmitting data towards one or more access
points in the first communication network and/or the second
communication network a database (53) for storing data; a processor
(51) for processing data received via said receiver and/or stored
in said memory; wherein the base station is arranged to manage a
list.
21. The base station of claim 20, wherein the transmitter is
further arranged to transmit said list via a broadcast channel.
22. The base station of claim 20, wherein the receiver is further
arranged to receive a request from a mobile device for providing
the list to the mobile device, and the base station is further
arranged to provide said list via said transmitter in response to
said request.
23. An access point (5, 60) within a first communication network,
the access point comprising: an access point memory (63) storing
information representative of the identity of the access point and
information representative of the position of the access point; a
receiver (67) for detecting one or more cellular base stations (3,
3a, 3b, 50) within a second communication network; a processor (61)
for enabling transmission of said access point identifier and
information representative of the position of the access point to
said one or more cellular base stations upon detection.
24. The access point of claim 23, wherein the receiver is further
arranged to receive data from a mobile device (1, 40), and the
access point further comprises a transmitter (69) to transmit at
least one of the information representative of the identity of the
access point and the information representative of the position of
the access point towards the mobile device.
25. The access point of claim 23, further comprising a position
determination unit (65) for determining the position of the access
point and storing the position in said access point memory.
26. The access point of claim 25, wherein said location
determination unit comprises a global positioning system, GPS,
receiver.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present patent application is a continuation of U.S.
patent application Ser. No. 12/639,758, entitled "Method of
Determining a Location of a Mobile Device and Method of Managing a
List for Use in Such a Method," filed Dec. 16, 2009, which claims
priority under 35 U.S.C. .sctn.119(b) to EP 08021968.6, which was
filed Dec. 18, 2008. The full disclosure of U.S. patent application
Ser. No. 12/639,758 is incorporated herein by reference.
FIELD
[0002] The invention relates to a method of determining a location
of a mobile device. Additionally, the invention relates to a mobile
device using such a method. Furthermore, the invention relates to a
method of managing a list of records of access points located
within a coverage area of a cellular base station. Additionally,
the invention relates to a cellular base station using such a
method. Finally, the invention relates to an access point for use
in such a method.
BACKGROUND
[0003] Nowadays, the use of mobile devices, e.g. personal digital
assistants, portable computers and mobile phones, for wireless
communication purposes is widespread. Furthermore, new applications
for these devices are rapidly emerging. In many of these new
applications, services are provided which relate to functionality
to the end user of the mobile device based on its location, so
called Location Based Services (LBS). Such services include for
example providing navigational support, providing a local weather
forecast or searching for a nearby restaurant.
[0004] Depending on the type of service to be provided, different
methods of determining the location of the mobile device can be
applied. Some services require very accurate locations, while
others only need to know the location in a more general
fashion.
[0005] Well-known methods of determining the location of a mobile
device are based on the location of a base station of the radio
cell the mobile device is camped on. In these methods, localization
may for example be based on cellular base station identifiers sent
by cellular base stations in the network. If the mobile device
knows the geographic location of the base stations corresponding to
the base station identifiers, it can determine its position. The
determination may be done by assuming that the position of the
mobile device coincides with the closest base station, by
calculating the position using a triangulation technique based on
positions of surrounding base stations, or by using other
techniques known to a person skilled in the art.
[0006] Because the coverage area of a cellular base station is
relatively large, the accuracy of the localization will be
relatively low. This may become an issue for future mobile device
applications, in particular if these applications involve LBS that
need a very accurate location determination. Especially in
buildings, the location determination can be improved, e.g. to
determine on which floor the mobile device is located.
[0007] One way to improve the accuracy of the determined position
is to base the location determination on wireless access points,
e.g. access points used in a wireless local area network (WLAN).
Wireless access points generally have a smaller coverage area than
cellular base stations. Furthermore, wireless access points are
often located in buildings. By using access point identifiers,
Service Set Identifier (SSID) in WLAN, a more precise location
determination is possible. A method of determining a location of a
mobile device based on wireless access points is described in U.S.
Pat. No. 6,968,194. A wireless access point that is equipped to be
used in such a method has for example been described in European
patent application 1802154.
[0008] In order to perform a location determination based on access
point identifiers, an accurate location of the wireless access
points themselves is needed. Unlike cellular base stations,
wireless access points are often installed by the general public,
not specifically skilled in operating (wireless) communication
technology. As a result, a person may install a wireless access
point without knowing how to assign a correct address or may forget
to change the location of the wireless access point after moving
the wireless access point to a new location. A three-point location
determination based on three wireless access points, also referred
to as triangulation, of which one access point has an inaccurate or
incorrect address, will result in an erroneous location of the
mobile device.
SUMMARY
[0009] A further improvement of precision with respect to the
location of a mobile device is desirable in view of future
applications for a mobile device. For this purpose, an accurate
location of the wireless access points themselves is desirable. It
is an object of embodiments to provide a method of accurately
determining a location of a mobile device with improved reliability
as compared to the prior art.
[0010] For this purpose, the embodiments relate to a method of
determining a location of a mobile device in a first communication
network, the mobile device being in communication with a cellular
base station in a second communication network, the method
comprising: [0011] detecting access points within the first
communication network with the mobile device; [0012] selecting one
or more of the detected access points based on information provided
by the cellular base station; and [0013] determining the location
of the mobile device based on the selected access points.
[0014] The information provided by the cellular base station may
comprise records regarding access points within the first
communication network that are indicated as being located within a
coverage area of the cellular base station. The method enables the
mobile device to accurately determine its location with higher
reliability. The assistance of the base station in the second
network facilitates a selection of access points with more reliable
information regarding their positions.
[0015] The information in the form of records may be used for the
selecting, e.g. by excluding detected access points for which no
record is present in the list. Such a list only comprises records
regarding access points whose position is "reliable".
[0016] The list may be provided in response to sending a request
towards the cellular base station. In this arrangement, the
capacity of a broadcast channel of the base station is not burdened
unnecessarily. Alternatively, the list may be provided via a
broadcast channel. This arrangement saves time, as the mobile
device can obtain the list without a need to send a request and
wait for a response.
[0017] The nominal coverage area of the cellular base station in
the second communication network may be larger than a nominal
coverage area of an access point within the first communication
network. A large coverage area of the base station in the second
network enables uncomplicated location determination over a large
geographical area, e.g. by the use of a single list in a way as
described above. A small coverage area of an access point
facilitates location determination with high accuracy.
[0018] In embodiments of the method, the method further comprises
reporting to the cellular base station in the second communication
network which access points in the first communication network have
been detected. The reporting may serve as a check on the access
points' positions. In general, the smaller the coverage area of the
access points compared to the size of the coverage area of the base
station, the greater the accuracy improvement will be from use of
the feedback.
[0019] The embodiments relate to a mobile device arranged to be
part of a first communication network and a second communication
network, the mobile device comprising: [0020] a receiver for
receiving data from one or more access points in the first
communication network and/or the second communication network;
[0021] a transmitter for transmitting data towards one or more
access points in the first communication network and/or the second
communication network; [0022] a memory for storing data; [0023] a
processor for processing data received via the receiver and/or
stored in the memory; wherein the mobile device is arranged to
perform embodiments of the aforementioned method.
[0024] The embodiments relate to a method of managing a list for
use in a cellular base station within a second communication
network, the list comprising records regarding access points within
a first communication network that are indicated as being located
within a coverage area of the base station, the method comprising:
[0025] receiving a message from an access point within the first
communication network regarding its position; [0026] checking
whether the position of the access point is located within the
coverage area; [0027] updating the list if the position is located
within the coverage area.
[0028] This method performs well if the base station knows its
position and coverage area, and if the messages contain correct
positions of the access points. Generally, the first condition is
met because installment by a provider at a certain position is
based on a planning of the second network which involves planning
of position and coverage area of the base stations to be installed.
In order to verify that the second condition is met, several
measures may be taken to improve the reliability of the position
reported by the access points and used to determine whether or not
the list should be updated to include a particular access point
record. These measures may include one or more of the following.
The access point records may comprise information representative of
the identity of the respective cells. In such a case, the updating
may include adding an access point record if the information
representative of the identity of the respective access point is
not present in the list. The access point record may further
comprise information representative of the position of the access
point. Then the updating may further include amending an access
point record if the information representative of the identity of
the respective access point is present in the list, but the
information representative of the position of the access point in
the stored access point record is different from the information
representative of the position of the access point in the
message.
[0029] In embodiments, the updating only occurs if one or more
mobile devices have reported that the access point has been
detected. The received reports may be used as a check on the access
points' positions. In general, the smaller the coverage area of the
access points compared to the size of the coverage area of the base
station, the greater the accuracy improvement will be from use of
the feedback.
[0030] The embodiments relate to a cellular base station
comprising: [0031] a receiver for receiving data from one or more
access points in the first communication network and/or the second
communication network; [0032] a transmitter for transmitting data
towards one or more access points in the first communication
network and/or the second communication network [0033] a database
for storing data; [0034] a processor for processing data received
via the receiver and/or stored in the memory; wherein the base
station is arranged to perform an embodiment of aforementioned
method of managing a list.
[0035] The receiver of the base station may be arranged to receive
a request from a mobile device for providing the list to the mobile
device. The base station may then be arranged to provide the list
via the transmitter in response to such request. In this
embodiment, the capacity of a broadcast channel of the base station
is not burdened unnecessarily. Alternatively, the transmitter of
the base station may be arranged to transmit the list via a
broadcast channel. Such an embodiment saves time, as the mobile
device can obtain the list without a need to send a request and
wait for a response.
[0036] Finally, the embodiments relate to an access point within a
first communication network, the access point comprising: [0037] an
access point memory storing information representative of the
identity of the access point and information representative of the
position of the access point; [0038] a receiver for detecting one
or more cellular base stations within a second communication
network; [0039] a processor for enabling transmission of the access
point identifier and information representative of the position of
the access point to the one or more cellular base stations upon
detection.
[0040] In embodiments, the access point comprises a position
determination unit, e.g. a global positioning system (GPS)
receiver, for determining the position of the access point and
storing the position in the access point memory. The use of a
position determination unit enables the access point to determine
its location in a relatively reliable manner.
[0041] Further aspects of the invention and embodiments as defined
in the claims will be clarified with reference to the attached
drawings and corresponding description. It will be understood that
the invention is not in anyway restricted to the embodiments
disclosed in these drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] FIG. 1 schematically depicts an exemplary network
architecture in which embodiments can be implemented;
[0043] FIG. 2 schematically depicts an embodiment of a method of
determining a location of a mobile device;
[0044] FIG. 3 schematically depicts another exemplary network
architecture in which embodiments can be implemented;
[0045] FIG. 4 schematically depicts an embodiment of a method of
managing a list of records of access points that are located within
the coverage area of a cellular base station;
[0046] FIG. 5 schematically depicts a mobile device according to an
embodiment;
[0047] FIG. 6 schematically depicts an embodiment of a cellular
base station that may be used in embodiments; and
[0048] FIG. 7 schematically depicts an embodiment of an access
point that may be used in embodiments.
DESCRIPTION
[0049] The following is a description of certain embodiments of the
invention, given by way of example only.
[0050] Throughout the description, the expression "coverage area"
has been used to refer to a geographical area in which signals can
be received from a transmitter in a communication network. For
clarity reasons, a coverage area of a transmitter has been depicted
as a circle. However, it must be understood that a shape of a
coverage area as defined above depends on the actual circumstances
and may have any other shape. Coverage areas of access points
within a communication network may vary in size, e.g. due to
ambient conditions, settings of the access point, etc. For this
reason, circles of different radius have been depicted in figures
supporting the description.
[0051] FIG. 1 schematically depicts an exemplary network
architecture in which the embodiments can be implemented. The
depicted network architecture comprises a mobile device 1, a
cellular base station 3 and a number of access points 5-1 to 5-5,
which may be, for example, wireless access points. The cellular
base station 3 has a coverage area 7. The access points 5-1 to 5-5
have coverage areas 9-1 to 9-5 respectively.
[0052] The mobile device 1 is positioned within a coverage area 7
of the base station 3 and is camped on the base station 3. The
mobile device 1 is further positioned within coverage areas of one
or more cells, i.e. in FIG. 1 coverage areas 9-2 to 9-5 of access
points 5-2 to 5-5 respectively.
[0053] The access points 5-1 to 5-5 are part of a first
communication network. The cellular base station 3 is part of a
second communication network. The mobile device 1 is arranged to be
part of both the first communication network and the second
communication network. Hereinafter the first communication network
will be referred to as the first network, and the second
communication network will be referred to as the second
network.
[0054] The first network may be a wireless communication network,
and may be arranged to support a first type of radio technology.
The first type of radio technology may typically comprise a
shorter-range wireless communication technology such as
Bluetooth.TM., Radio Frequency Identification (RFID), WLAN,
Worldwide Interoperability for Microwave Access (WIMAX.TM.), Near
Field Communication (NFC), Ultra Wide Band (UWB), Zigbee.TM.
Digital Enhanced Cordless Telecommunications (DECT), Wibree.TM.,
and other suitable technologies. In the example shown in FIG. 1,
the access points 5-1 to 5-5 and the mobile device are equipped
with interfaces for communication using the first type of radio
technology.
[0055] The second network may be arranged to support a second type
of radio technology. The second type of radio technology may
typically comprise a standard cellular radio technology used for
mobile phones, such as Global System for Mobile telecommunications
(GSM), Universal Mobile Telecommunications System (UMTS), Wideband
Code Division Multiple Access (WCDMA), Long Term Evolution (LTE),
Interim Standard 95 (IS-95), Code Division Multiple Access 2000
(CDMA2000), WIMAX, Digital Video Broadcasting (DVB), technologies
related to a private mobile radio standard like Terrestrial Trunked
Radio (TETRA), technologies related to a satellite communication
standard provided by a standard body like the International Mobile
Satellite Organization (InMarSat) or other suitable technologies.
In the example shown in FIG. 1, the base station 3 and the mobile
device 1 are equipped with interfaces for communication using the
second type of radio technology.
[0056] It is also possible that the second type of radio technology
may be selected from the first list provided above, or that the
first type of radio technology may be selected from the second list
provided above.
[0057] FIG. 2 schematically depicts a flow diagram of an embodiment
of a method of determining a location of a mobile device. The
method in FIG. 2 will be explained with reference to the exemplary
network architecture depicted in FIG. 1.
[0058] In the shown embodiment, in action 21, access points within
a first network are detected with a mobile device. The mobile
device 1 may detect the access points by scanning for signals
transmitted by the access points. In FIG. 1, the mobile device 1 is
able to receive signals transmitted by access points 5-2, 5-3, 5-4
and 5-4, because it is positioned in their respective coverage
areas, i.e. coverage areas 9-2, 9-3, 9-4 and 9-5 respectively.
Although access point 5-1 is positioned within the coverage area 7
of the cellular base station 3, the mobile device 1 does not detect
access point 5-1. Therefore, access point 5-1 will not be used in
further actions of the method of determining a location of a mobile
device according to the embodiments.
[0059] Then, in action 23, detected access points are selected with
the assistance of a base station in a second network, i.e. in FIG.
1 cellular base station 3.
[0060] Finally, in action 25, a location of the mobile device is
determined based on positions of the selected access points.
[0061] The method schematically depicted enables the mobile device
to accurately determine its location with higher reliability. The
assistance of the base station in the second network facilitates a
selection of access points with more reliable information regarding
their positions.
[0062] Providing assistance to the mobile device for selecting
certain access points out of a group of detected access points may
be done in the following way. The base station may be arranged to
provide a list of records regarding access points within the first
network that are located within the coverage area of the base
station. The base station could manage the list in such a way that
only access points that are confirmed to be in its coverage area
are listed. Thus, the list only comprises records regarding access
points whose position is "reliable".
[0063] In the exemplary network architecture depicted in FIG. 1,
the list would be provided by base station 3 and would contain
access point records of the access points located within the
coverage area 7, i.e. access points 5-1, 5-2, 5-3 and 5-4.
[0064] The list may be provided in response to sending a request by
the mobile device to the base station. The base station then
provides the list when needed. In this arrangement, the capacity of
a broadcast channel of the base station is not burdened
unnecessarily.
[0065] Alternatively, the list may be provided via the broadcast
channel, i.e. the base station may be arranged to broadcast the
list via a broadcast channel. Such an embodiment saves time, as the
mobile device can obtain the list without a need to send a request
and wait for a response.
[0066] The selecting in action 23 may comprise excluding detected
access points for which no record is present in the list provided
by the base station. In FIG. 1, access points 5-2, 5-3, 5-4 and 5-5
will be detected by the mobile device 1. However, access point 5-5
is not located within the coverage area 7 of the base station 3,
and will therefore not be on the list provided to mobile device 1.
Because there is no further information regarding the reliability
of the position of access point 5-5, this access point may be
excluded for further use in the method of determining the location
of the mobile device 1.
[0067] The access point records in the list may include information
representative of the identity of the access point, hereinafter
referred to as access point identifier. The access point identifier
may take the form of a Media Access Control (MAC) address, an SSID,
or other suitable code for identifying the access point. The list
of access point records may be stored in the mobile device. A
record may further comprise information representative of the
position of the access points, hereinafter referred to as position
information. This access point position information will usually
originate from the access point itself, e.g. having been stored in
a memory of the access point upon installation of the access point,
or may originate from some other location in the network. The
access point may transmit the position information to the mobile
device 1, e.g. via a broadcast channel.
[0068] Once certain access points have been selected, the location
of the mobile device is determined in action 25, based on the
positions of the selected access points. This may be accomplished
in various ways, depending on the number of access points selected
and the information available. For example, if there is only one
selected access point, it can be assumed that the location of the
mobile device coincides with that access point. The access point
position information is then used as the mobile device location. If
there is more than one selected access point, the location of the
mobile device may be determined by calculating a position in
between the selected access points using the access point position
information of each selected access point. For example, if there
are two selected cells, the location of the mobile device may be
assumed to be mid-way between the two access points. If there are
three or more selected cells, the location of the mobile device can
be calculated using a triangulation technique.
[0069] These methods rely on the access point position information,
but other information may also be used in addition to the position
information. For example, where feasible, the strength of the
signals from the selected access points may be used in calculating
the distance of the mobile device from an access point, the
direction from which the signals from the selected access points
originate, or the phase of the signals from the selected cells, may
be used in calculating the location of the mobile device.
[0070] Application of the method schematically depicted in FIG. 2
to provide the location of the mobile device 1 within the exemplary
network architecture schematically depicted in FIG. 1, results in
determining the location based on the positions of access points
5-2, 5-3 and 5-4. These are the access points that were both
detected by the mobile device and confirmed by the base
station.
[0071] In the embodiments, the mobile device may report to the base
station which access points were detected during action 21. If one
or more mobile devices have reported an access point from within
the coverage area of the base station, the base station then
assumes that the access point is located within its coverage area
and adds the access point to the list. Similarly, if during a
certain period of time, or by a number of mobile devices being
located within the coverage area of the base station, no mobile
device has reported that an access point is detected even though
the access point is present on the list, the base station may
decide to remove the access point from the list. More details
regarding list management will be discussed with reference to FIG.
3, which describes an embodiment of a method of managing such a
list.
[0072] Embodiments of the method of determining a location of a
mobile device become more efficient if a nominal coverage area of
the base station in the second network is larger than a nominal
average coverage area of an access point within the first network.
A large coverage area of the base station in the second network
enables uncomplicated location determination over a large
geographical area, e.g. by the use of a single list in a way as
described above. A small coverage area of an access point
facilitates location determination with high accuracy.
[0073] The method described with reference to FIG. 2 may also be
applied in situations where the mobile device 1 is located within a
coverage area of more than one base station 3. FIG. 3 schematically
depicts an exemplary network architecture in which the mobile
device 1 is positioned within a coverage area of two different base
stations, i.e. a first cellular base station 3a and a second
cellular base station 3b. The base stations 3a, 3b have a first
coverage area 7a and a second coverage area 7b respectively.
[0074] The network architecture further comprises a number of
access points 5-1 to 5-8, e.g. wireless access points, that are
part of the first network. The base stations 3a, 3b are part of the
second network. Again, the mobile device 1 is arranged to be part
of both the first and the second network.
[0075] In the exemplary network architecture schematically depicted
in FIG. 4, the mobile device 1 may perform the method as
schematically shown in FIG. 2. The detection action remains similar
to the one described with reference to FIG. 2. However, in the
exemplary network architecture of FIG. 4, the selecting may be
performed with assistance of either one of or both base stations
3a, 3b. In an embodiment, the first base station 3a provides a
first list, and the second base station 3b provides a second list
to the mobile device 1. The first list comprises records of access
points within the first network that are located within the first
coverage area 7a, i.e. access points 5-1, 5-2, 5-3 and 5-4. The
second list comprises records of access points within the first
network that are located within the second coverage area 7b, i.e.
access points 5-2, 5-6, 5-7 and 5-8. Both lists may be stored
within the mobile device 1. Alternatively, the mobile device 1 may
facilitate a merging of the two lists into a single list to be
stored.
[0076] The action of detecting results in the detection of access
points 5-2, 5-3, 5-4, 5-5 and 5-8. In embodiments using one or more
lists as described above, detected access points 5-2, 5-3 and 5-4
are present on the first list. Furthermore, detected access points
5-2 and 5-8 are present on the second list. Note that detected
access point 5-5 is neither present on the first list nor on the
second list. Access point 5-5 will therefore be excluded from use
in the action of determining.
[0077] Determining the location of the mobile device 1 may then
based on the positions of the detected access points that are
present on the first list or second list, i.e. in the exemplary
network architecture of FIG. 3, access points 5-2, 5-3, 5-4 and
5-8. Alternatively, determining the location of the mobile device 1
may be based on the positions of detected access points that are
present on both the first list and the second list, access point
5-2. The latter embodiment is generally more accurate.
[0078] It can be readily understood that the method of determining
a location of a mobile device as described with reference to FIGS.
1-3. If the assistance provided by the base station is highly
reliable and up to date. That is, in case a list is used as
discussed with reference to FIG. 2, only access point records of
access points that are actually within the coverage area of the
base station should be present in the list.
[0079] Generally, within a coverage area of a base station in the
second network, the number and locations of access points within
the first network vary. For example, new access points may be
activated or deactivated, access points may change location within
the coverage area of the base station, or access points may move
inside or outside the coverage area.
[0080] FIG. 4 schematically depicts an embodiment of a method of
managing a list for use in a base station in a second network, the
list comprising records of access points within a first network
that are located within the coverage area of the base station, e.g.
base station 3 in FIG. 1 or base station 3a, 3b in FIG. 3. An
access point record comprises an access point identifier for
identifying the access point. Furthermore, the access point record
may comprise information representative of the position of the
access point. The managing method will be discussed with reference
to the situation where the list is stored in the base station.
However, it should be noted that, alternatively, the list may be
stored in a data storage mode of the second network, and forwarded
as needed.
[0081] First, in action 31, the base station receives a message
from an access point within the first network regarding its
position. The base station may be part of the second network. The
message may then be received via a communication interface within
that network. Alternatively and/or additionally, the message may be
sent via a fixed network, e.g. Internet or a Public Switched
Telephone Network (PSTN).
[0082] In action 33, upon reception of the message in action 31,
the base station checks whether the position mentioned by the
access point is located within its coverage area. The coverage area
of a base station may vary over time, e.g. as a consequence of
atmospheric changes. Therefore, the coverage area used in the check
of action 33 may relate to a nominal coverage area or an average
area covered by the base station under most conditions. If the
position mentioned by the access point is located within the
coverage area of the base station, the list may be updated in
action 35.
[0083] This method performs well if the base station knows its
position and coverage area, and if the messages contain correct
positions of the access points. Generally, the first condition is
met because installment by a provider at a certain position is
based on a planning of the second network which involves planning
of position and coverage area of the base stations to be installed.
In order to verify that the second condition is met, several
measures may be taken to improve the reliability of the position
reported by the access points and used to determine whether or not
the list should be updated to include a particular access point
record. The term "reliability" refers to the chance that an access
point is actually located within the coverage area of the base
station if the access point is present in the list. The higher the
chance that the access point is indeed located within the coverage
area of the base station, the higher the reliability.
[0084] In an embodiment, the base station receives feedback from
one or more mobile devices in its coverage area to confirm that the
access points which report that they are in the base station's
coverage area are actually there. Where a mobile device is in
communication with the base station and is thus in its coverage
area, the mobile device may send the base station information about
the access points which the mobile device has detected. This
operates as a check on the access points' positions. In general,
the smaller the coverage area of the access points compared to the
size of the coverage area of the base station, the greater the
accuracy improvement will be from use of this feedback.
[0085] For example, after checking whether the position reported by
an access point is located within the coverage area in action 33,
the base station may waits before performing action 35, i.e.
updating the list, until one or more mobile devices have reported
that the access point has been detected in action 37. The fact that
a mobile device, which is in communication with the base station,
is able to detect the access point, implies that there is a
reasonable chance that the access point is located within the
coverage area of the base station.
[0086] For example, in FIG. 3, access point 5-7 is located outside
the coverage area 7a of the base station 3a, and within the
coverage area 7b of base station 3b. The access point 5-7 could
communicate with base stations 3a, 3b via a fixed network and
report in a message a position that is located within coverage area
7a and outside coverage area 7b. This message contains an erroneous
position, but the base station 3a recognizes that this position is
located within its coverage area, and therefore may update the list
to include access point 5-7. On the other hand, base station 3b
recognizes that this position is located outside its coverage area,
and therefore does not update the list to include access point 5-7.
By using action 37, access point 5-7 will not be added to the list
of base station 3a because the mobile device 1 cannot detect access
point 5-7. On the other hand, a mobile device 1 located within the
coverage area of base station 3b may be able to detect the access
point 5-7 and report its detection to base station 7b.
[0087] The base station may want to have more than one mobile
device to detect the access point to improve the reliability even
further. If a number of mobile devices detect the access point 5-7
while in communication with base station 7b, the base station 7b
may decide to add the access point 5-7 to the list. Furthermore,
other errors may be avoided.
[0088] For example, in FIG. 1, access point 5-5 is located outside
the coverage area 7 of the base station 3. The access point 5-5
could communicate with base station 3 via a fixed network and
report in a message a position that is located within the coverage
area 7. This message contains an erroneous position, but, without
performing an additional action such as action 37, the base station
3 may not detect the error and may update its list to include
access point 5-5.
[0089] The mobile device 1 in FIG. 1 will detect access point 5-5.
However, because the coverage areas of base station 3 and access
point 5-5 only have a small overlapping area, a mobile device
located at many other positions within the coverage area of the
base station 3 will not detect access point 5-5. Therefore, if many
mobile devices in communication with the base station 3 do not
detect access point 5-5, and only a few do, the base station 3 may
decide not to update its list to include access point 5-5.
[0090] Alternatively or additionally, further measures may be taken
to improve the reliability of the list. In an embodiment, the base
station may verify the position reported by the access point via
the message in action 39. If the verification reveals that the
position is correct, the base station may proceed to action 35,
i.e. updating the list. Verification may be performed by
transmitting a request to the access point and analyzing the
response. If the base station and the access point can both
communicate on the same communication network, the verification can
be sent via this network. For example, if the access point is
equipped with an interface for communicating via the second
network, the verification request can be sent via this network. If
the base station is located within the coverage area of the access
point, the access point can send a response via the second network
as well. If the base station is equipped with an interface for
communicating via the first network, the verification request can
be sent via the first network. If the base station is located
within the coverage area of the access point, the access point can
send a response via the first network as well. If the base station
is not part of the first network and/or is not located within the
coverage area of the access point, a verification response may be
sent via a fixed network, e.g. Internet or a PSTN.
[0091] In general, the smaller the coverage area of the access
points compared to the size of the coverage area of the base
station, the greater the accuracy improvement will be from use of
this additional verification.
[0092] For example, in FIG. 1, access point 5-5 is located outside
the coverage area 7 of base station 3. Access point 5-5 could try
to contact base station 3 via a fixed network and erroneously
report a position within the coverage area 7. The verification
action performed by base station 3 does not result in a response by
the access point 5-5, because access point 5-5 cannot be reached by
the base station via the first and/or second network. Hence, access
point 5-5 will not be included in the list.
[0093] The updating in action 35 may include adding an access point
record if the access point identifier is present in the list. The
updating may further include amending an access point record if
there is an access point record in the list that includes the
access point identifier mentioned in the message, but the
information representative of the position of the access point in
the stored access point record is different from the position
information in the message from the access point. The latter
situation may occur if an access point is moved from a first
position to a second position, where both the first and second
position are located within the coverage area of the base
station.
[0094] FIG. 5 schematically depicts an embodiment of a mobile
device 40 according to an embodiment. The mobile device 40 is
arranged to perform embodiments of a method of determining a
location of a mobile device in a first network, e.g. the method
schematically depicted in and explained with reference to FIG. 2.
The mobile device in FIG. 5 comprises a processor 41, a memory 43,
a receiver 47 and a transmitter 49. The processor 41 is
communicatively coupled to the memory 43. The processor 41 may
comprise a control unit to control signals received by the receiver
47 and signals to be sent via the transmitter 49, e.g. for the
purpose of controlling detection. The receiver 47 may be arranged
to operate within the first network and the second network.
Alternatively, the mobile device may comprise two receivers, a
first receiver arranged to operate within the first network, and a
second receiver arranged to operate within the second network.
[0095] FIG. 6 schematically depicts an embodiment of a base station
50 that may be used in the embodiments shown in FIG. 1-3, i.e. as
base station 3, 3a or 3b. The base station 50 of FIG. 6 may further
be used to implement a method of managing a list of records of
access points that are located within its coverage area. An
embodiment of such a method has been discussed with reference to
FIG. 4.
[0096] The base station 50 comprises a processor 51 communicatively
coupled to a database 53. In the database 53, a list of records of
access points within a first network may be stored, the access
points being located within the coverage area of the base station
50. The base station is part of a second network.
[0097] The base station 50 further comprises a receiver 57 and a
transmitter 59. The receiver 57 and the transmitter 59 are arranged
to communicate via a communication interface within the second
network, and may be able to communicate via a communication
interface within the first network as well. In embodiments, the
base station 50 may further comprise an interface 58. The interface
58 may be connected to a fixed network, e.g. Internet or a
PSTN.
[0098] FIG. 7 schematically depicts an embodiment of an access
point 60 that may be used in embodiments, i.e. an access point
within the first network. The access point 60 comprises a processor
61, a memory 63, a receiver 67, and a transmitter 69.
[0099] The receiver 67 may be arranged to receive signals from a
mobile device. The receiver 67 may further be arranged to detect
one or more base stations within the second network.
[0100] The processor 61 may comprise a control unit to control
signals received by the receiver 67 and signals to be sent via the
transmitter 69, e.g. for the purpose of controlling detection of
base stations or for the purpose of responding to signals received
from a mobile device. Alternatively, or additionally, the processor
61 may enable transmission of the access point identifier and
position information of the access point in a different way, e.g.
by transmission via a fixed network like Internet or a PSTN.
[0101] The access point memory 63 is configured to store or stores
an access point identifier and position information of the access
point 60. The access point identifier may already have been stored
in the access point memory 63 at the time of manufacturing. The
data regarding the position of the access point 60 may be provided
via a user interface (not shown), e.g. via a keyboard, touch
screen, etc.
[0102] The transmitter 69 may be arranged to transmit the access
point identifier and the position information of the access point,
e.g. in response to a signaling request received from a mobile
device. Furthermore, the transmitter 69 may transmit the access
point identifier and the position information to one or more
detected base stations, in particular if the respective base
station is part of the first network and located within the
coverage area of the access point 60.
[0103] The position information of the access point may be in any
format known to a person skilled in the art. For example, the
position information may take the form of x- and y-coordinates
(optionally also a z-coordinate), longitude-latitude coordinates
(optionally an altitude coordinate as well) or relate a certain
type of coding, e.g. a postal code or a postal address.
[0104] In an embodiment, the access point 60 further comprises a
position determination unit 65 for determining the position of the
access point 60. The position determination unit 65 may make use of
the receiver 67 and the transmitter 69 of the access point 60 for
this purpose. If the position has been determined, the position may
be stored in the access point memory 63. The location determination
unit may comprise a global positioning system (GPS) receiver.
[0105] In FIG. 7, data transferred in view of the determining of a
position by means of a position determination unit has been shown
with the dashed arrows. Data related to the scanning action, has
been depicted by means of the solid arrows.
[0106] The invention has been described by reference to certain
embodiments discussed above. It will be recognized that these
embodiments are susceptible to various modifications and
alternative forms well known to those of skill in the art.
Abbreviations
CDMA2000 Code Division Multiple Access 2000
DECT Digital Enhanced Cordless Telecommunications
DVB Digital Video Broadcasting
[0107] GSM Global System for Mobile telecommunications
InMarSat International Mobile Satellite Organization
IS-95 Interim Standard 95
LBS Location Based Services
LTE Long Term Evolution
MAC Media Access Control
NFC Near Field Communication
RFID Radio Frequency Identification
SSID Service Set Identifier
TETRA Terrestrial Trunked Radio
UMTS Universal Mobile Telecommunications System
UWB Ultra Wide Band
WCDMA Wideband Code Division Multiple Access
WIMAX Worldwide Interoperability for Microwave Access
[0108] WLAN Wireless Local Area Network
* * * * *