U.S. patent application number 12/336744 was filed with the patent office on 2009-06-18 for method for exchanging messages in a navigation system using visible light communications.
Invention is credited to Jong-Hoon Ann, Noh-Gyoung Kang, Dae-Seok Kim, Seung-Hoon Park, Jae-Seung Son, Eun-Tae WON.
Application Number | 20090157309 12/336744 |
Document ID | / |
Family ID | 40754352 |
Filed Date | 2009-06-18 |
United States Patent
Application |
20090157309 |
Kind Code |
A1 |
WON; Eun-Tae ; et
al. |
June 18, 2009 |
METHOD FOR EXCHANGING MESSAGES IN A NAVIGATION SYSTEM USING VISIBLE
LIGHT COMMUNICATIONS
Abstract
Method and device for exchanging messages in a VLC navigation
system is provided, in which a map server generates a provision
message in the form of visible light signals through all lamps in
an area, using a PLC network, where a navigation service is
provided, a terminal that wants to implement the navigation service
among terminals that have received the provision message transmits
a registration request message to the map server, the map server
transmits a registration response message for the registration
request message to the terminal, the terminal transmits a map
request message including information about a destination to the
map server, the map server transmits a map response message
including information about a path to the destination to the
terminal, and the terminal displays map information and the
path.
Inventors: |
WON; Eun-Tae; (Seoul,
KR) ; Ann; Jong-Hoon; (Suwon-si, KR) ; Kim;
Dae-Seok; (Seoul, KR) ; Kang; Noh-Gyoung;
(Seoul, KR) ; Park; Seung-Hoon; (Seoul, KR)
; Son; Jae-Seung; (Suwon-si, KR) |
Correspondence
Address: |
CHA & REITER, LLC
210 ROUTE 4 EAST STE 103
PARAMUS
NJ
07652
US
|
Family ID: |
40754352 |
Appl. No.: |
12/336744 |
Filed: |
December 17, 2008 |
Current U.S.
Class: |
701/533 |
Current CPC
Class: |
H04B 10/116 20130101;
H04B 10/1149 20130101; G01C 21/20 20130101 |
Class at
Publication: |
701/209 ;
701/200 |
International
Class: |
G01C 21/00 20060101
G01C021/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 18, 2007 |
KR |
10-2007-0133315 |
Claims
1. A method for exchanging messages in a Visible Light
Communication (VLC) navigation system, comprising: generating a
provision message in the form of visible light signals through each
of a plurality of lamps in an area where a navigation service is
provided by a map server; transmitting a registration request
message to the map server by a terminal that wants to implement the
navigation service among terminals that have received the provision
message; transmitting a registration response message for the
registration request message to the terminal by the map server;
transmitting a map request message including information about a
destination to the map server by the terminal; transmitting a map
response message including information about a path to the
destination to the terminal by the map server; and displaying map
information and the path by the terminal.
2. The method of claim 1, further comprising transmitting lamp
Identifier (ID) messages to all lamps positioned along a path in
which the terminal moves by the map server.
3. The method of claim 2, wherein each of the lamp ID messages
includes a terminal ID and a lamp ID.
4. The method of claim 1, wherein the provision message includes a
terminal ID, a building ID, a version of data that can be changed
during operation of the VLC navigation system, and a destination
list.
5. The method of claim 4, wherein the terminal ID is a
predetermined broadcasting ID in the provision message.
6. The method of claim 1, wherein the registration request message
includes a terminal ID and a building ID.
7. The method of claim 1, wherein the registration response message
includes a terminal ID, a building ID, map information.
8. The method of claim 7, wherein the map information is about a
map of an area where the terminal is located in the registration
response message.
9. The method of claim 1, wherein the map request message includes
a terminal ID, a building ID, a version of data that can be changed
during operation of the VLC navigation system, and the destination
information.
10. The method of claim 1, wherein the map response message
includes a terminal ID, a lamp ID, a version of data that can be
changed during operation of the VLC navigation system, the map
information, and the optimum path information.
11. The method of claim 10, wherein the map information is about an
entire map covering a current location of the terminal to the
destination in the map response message.
12. A method for exchanging messages in a Visible Light
Communication (VLC) navigation system, comprising: generating a
provision message in the form of visible light signals through all
lamps in an area where a navigation service is provided by a map
server; transmitting a registration request message to the map
server by a terminal that wants to implement the navigation service
among terminals that have received the provision message;
transmitting a registration response message for the registration
request message to the terminal by the map server; transmitting a
map request message including information about a destination to
the map server by the terminal; transmitting a map response message
including information about an optimum path to the destination to
the terminal, separately in a plurality of messages, each message
including a predetermined data amount by the map server; and
displaying map information and the optimum path by the
terminal.
13. The method of claim 12, further comprising transmitting lamp
Identifier (ID) messages to all lamps positioned along a path in
which the terminal moves by the map server.
14. The method of claim 13, wherein each of the lamp ID messages
includes a terminal ID and a lamp ID.
15. The method of claim 13, further comprising transmitting a
current location report message every predetermined period to the
map server by the terminal.
16. The method of claim 15, wherein the current location report
message includes a terminal ID and a lamp ID.
17. The method of claim 12, wherein the provision message includes
a terminal ID, a building ID, a version of data that can be changed
during operation of the VLC navigation system, and a list of a
plurality of sections each having a predetermined size into which
an entire area of a building is divided.
18. The method of claim 17, wherein the terminal ID is a
predetermined broadcasting ID in the provision message.
19. The method of claim 12, wherein the registration request
message includes a terminal ID, a building ID, an ID of a lamp
corresponding to a current area of the terminal, and an ID of a
current section of the terminal.
20. The method of claim 12, wherein the registration response
message includes a terminal ID, a building ID, a version of data
that can be changed during operation of the VLC navigation system,
information about an entire map of a current section of the
terminal, and map information about a current area of the
terminal.
21. The method of claim 12, wherein the map request message
includes a terminal ID, a building ID, a version of data that can
be changed during operation of the VLC navigation system, and the
destination information.
22. The method of claim 12, wherein the map response message
includes a terminal ID, an ID of a lamp corresponding to a current
area of the terminal, the map information, and the optimum path
information.
23. The method of claim 22, wherein the map information is about an
entire map covering a current location of the terminal to the
destination in the map response message.
24. A mobile terminal including at least a VLC communication system
comprising: a processor in communication with a memory, the memory
including code which when accessed by the processor causes the
processor to execute the following: transmitting a registration
request message to a map server that wants to implement the
navigation service; receiving a registration response message for
the registration request message transmitted by the map server;
transmitting a map request message including information about a
destination to the map server; receiving a map response message
including map information regarding a path to the destination
transmitted by the map server; and displaying said map information
and the path.
25. The terminal of claim 24, further comprising: receiving lamp
Identifier (ID) messages to all lamps positioned along the
path.
26. The terminal of claim 25, wherein said ID messages are
transmitted concurrently.
27. The terminal of claim 25, wherein said ID messages are
transmitted sequentially.
28. The terminal of claim 27, wherein said ID messages are
transmitted dependent upon a current location of said terminal.
29. The terminal of claim 27, wherein an identification of at least
one prior and one intended ID message is transmitted based on a
current location of said terminal.
Description
CLAIM OF PRIORITY
[0001] This application claims the benefit of the earlier filing
date, under 35 U.S.C. .sctn.119(a), to that Korean Patent
Application filed in the Korean Intellectual Property Office on
Dec. 18, 2007 and assigned Serial No. 2007-133315, the entire
disclosure of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention generally relates to a Visible Light
Communication (VLC) navigation system and more particularly, to a
method for exchanging messages between a visible light terminal and
a navigation server in a navigation system.
[0004] 2. Description of the Related Art
[0005] Owing to the improved light emission efficiency and
decreased price of Light Emitting Diodes (LEDs), LEDs have gained
popularity in the general lighting market, which includes
fluorescent lighting and incandescent lighting, as well as in the
special lighting market, including portable devices, displays,
cars, signal signs, and advertisement boards.
[0006] Also, optical wireless communication technology, as
complimentary to RF technology, has attracted much interest due to
the shortage of Radio Frequency (RF) bands, the possibility of
interference between different radio communication technologies,
increased demands for communication security, and the advent of an
ultra-high ubiquitous communication environment of 4.sup.th
Generation (4G) radio technology. In this context, many companies
and research institutes are studying VLC using visible light
LEDs.
[0007] VLC for transmitting information by light visible to the
human eye offers the benefits of a wide bandwidth, free use,
without restrictions, compared to wave communications, visibility
of the destination or passage of light, and the resulting accurate
detection of an information reception range. Therefore, VLC is
reliable in terms of security and consumes low power. In this
context, VLC can be applied to hospitals and airplanes where RF use
is restricted and provide additional information services through
an advertisement board. A VLC system will be described below.
[0008] FIG. 1A illustrates a conventional VLC system. The
conventional VLC system includes LED or Laser Diode (LD) lamps 141,
142 and 143 for acting as lights and transmitting and receiving
data by visible light, and communication devices 150 and 160 each
having a visible transceiver module for transmitting and receiving
data to and from the lamps 141, 142 and 143. The communication
devices 150 and 160 can be a mobile terminal such as a portable
phone or a Personal Digital Assistant (PDA), or a fixed terminal
such as a desktop computer.
[0009] FIG. 1B illustrates a VLC-based peripheral interface system.
In the VLC-based peripheral interface system, a communication
device 170 like a laptop or a desktop that has a visible light
transceiver module, a portable mobile terminal 180 such as a
hand-held phone or a PDA, a peripheral device 190 like a printer,
or a small digital device like a digital camera or an mp3 player
communicate with one another by visible light. A VLC-based
peripheral device interface guarantees security and is implemented
with low power.
[0010] The VLC can be more efficient through convergence with other
wired or wireless communication systems using different
communication media. Among them, a VLC system for providing
information by lighting inside a building in conjunction with Power
Line Communication (PLC) will be described below in detail.
[0011] FIG. 2 illustrates a conventional communication system using
PLC and VLC in combination. In FIG. 2, a conventional method for
providing location-based information to a user over a lamp network
by PLC is illustrated (see, for example, Korea Patent Publication
No. 10-2005-71617 entitled "Illumination Light Communication Device
mark, filed by Nakagawa, et al., on Apr. 23, 2005). In the
conventional technology, power and information are simultaneously
transferred via a power line 103. A lamp 131 connected to the power
line 103 modulates information received via the power line 103 to a
visible light signal and provides the modulated information to a
user 133. In this illustrated example, the information may about a
piece of art work 132 positioned in an area illuminated by the lamp
131.
[0012] FIG. 3 is a diagram illustrating a message exchange
procedure between network entities in the conventional
communication system using PLC and VLC illustrated in FIG. 2.
[0013] Referring to FIG. 3, a server 134 transmits information to
lamps 131 forming a lamp network via a power line and the lamps 131
generate visible light signals by VLC. The conventional
location-based service using a power line simply provides
information about a fixed object to a mobile terminal, thus having
limitations in information transmission.
[0014] Meanwhile, mobile communication terminals including portable
phones, Personal Communications Services (PCSs), International
Mobile Telecommunication-2000 (IMT-2000) terminals, and PDAs are
equipped with various convenient functions such as a message
transmission/reception function, a wireless Internet function, a
schedule management function, a camera function, a music player
function, an electronic dictionary function, and a navigation
function in addition to a simple voice call function.
[0015] Among the convenient functions, a Global Positioning System
(GPS)-based navigation function is used for indicating to a user a
path and direction to a destination entered by the user. In
general, since the navigation function is designed to provide
information about the current location of a vehicle, it can search
for a path based on map data stored in a database.
[0016] Beyond this vehicle navigation system, navigation for a
walker as well as for a vehicle is under development. A pedestrian
navigation device indicates a path to a destination to a user
carrying the pedestrian navigation device and allows the user to
monitor the user's progress along the path.
[0017] When a pedestrian enters a building or underground, however,
the GPS-based navigation service is not available as GPS signals
cannot be received. Accordingly, there exists a need for navigation
inside a building along with the trend of increasing construction
of large-scale building structures such as skyscrapers, huge
shopping malls, and large underground arcades.
SUMMARY OF THE INVENTION
[0018] Accordingly, an aspect of exemplary embodiments of the
present invention is to provide a navigation system for providing a
navigation service by VLC inside a large-scale building structure
blocking GPS signal reception, like a skyscraper, and a method for
exchanging messages between a terminal and a navigation server in
the navigation system.
[0019] In accordance with an aspect of exemplary embodiments of the
present invention, there is provided a method for exchanging
messages in a VLC navigation system, in which a map server
generates a provision message in the form of visible light signals
generated through lamps in an area where a navigation service is
provided, a terminal that wants to implement the navigation service
among terminals that have received the provision message transmits
a registration request message to the map server, the map server
transmits a registration response message for the registration
request message to the terminal, the terminal transmits a map
request message including information about a destination to the
map server, the map server transmits a map response message
including information about an optimum path to the destination to
the terminal, and the terminal displays map information and the
optimum path.
[0020] In accordance with another aspect of exemplary embodiments
of the present invention, there is provided a method for exchanging
messages in a VLC navigation system, in which a map server
generates a provision message in the form of visible light signals
through all lamps in an area where a navigation service is
provided, a terminal that wants to implement the navigation service
among terminals that have received the provision message transmits
a registration request message to the map server, the map server
transmits a registration response message for the registration
request message to the terminal, the terminal transmits a map
request message including information about a destination to the
map server, the map server transmits a map response message
including information about a path to the destination to the
terminal, separately over a plurality of times, each time in a
predetermined data amount, and the terminal displays map
information and the optimum path.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The above features and advantages of certain exemplary
embodiments of the present invention will be more apparent from the
following detailed description taken in conjunction with the
accompanying drawings, in which:
[0022] FIG. 1A illustrates a conventional VLC system;
[0023] FIG. 1B illustrates a VLC-based peripheral interface
system;
[0024] FIG. 2 illustrates a conventional communication system using
PLC and VLC in combination;
[0025] FIG. 3 is a diagram illustrating a message exchange
procedure between network entities in the conventional
communication system using PLC and VLC illustrated in FIG. 2;
[0026] FIG. 4 illustrates the configuration of a navigation system
according to an exemplary embodiment of the present invention;
[0027] FIG. 5 is a diagram illustrating a message exchange
procedure between network entities in the navigation system
according to an exemplary embodiment of the present invention;
and
[0028] FIG. 6 is a diagram illustrating a message exchange
procedure between network entities in the navigation system
according to another exemplary embodiment of the present
invention.
[0029] Throughout the drawings, the same drawing reference numerals
will be understood to refer to the same elements, features and
structures.
DETAILED DESCRIPTION OF THE INVENTION
[0030] The matters defined in the description such as a detailed
construction and elements are provided to assist in a comprehensive
understanding of exemplary embodiments of the invention.
Accordingly, those of ordinary skill in the art will recognize that
various changes and modifications of the embodiments described
herein can be made without departing from the scope and spirit of
the invention. Also, descriptions of well-known functions and
constructions are omitted for clarity and conciseness.
[0031] Exemplary embodiments of the present invention provide an
indoor navigation system for providing a navigation function within
a large-scale building structure such as a skyscraper or a huge
mall by VLC and a message exchange procedure between a mobile
terminal and a navigation server in the navigation system.
[0032] To overcome the problem encountered with a conventional
GPS-based navigation system that navigation information is not
available in a GPS shadow area like building indoors, the present
invention implements a VLC-based navigation system using visible
light emitting from a light(s) inside a building, for example. In
other words, the building lights are fixed and thus emit light to
predetermined areas inside a building. Hence, when a building
indoor map is acquired, each light is located, and an Identifier
(ID) may b allocated to each light. The corresponding area
illuminated by each light is thus known. Therefore, when a mobile
terminal communicates with a light illuminating an area in which
the mobile terminal is located, the mobile terminal can determine
its current location by checking the ID of the light.
[0033] FIG. 4 illustrates the configuration of a navigation system
according to an exemplary embodiment of the present invention.
[0034] Referring to FIG. 4, the navigation system includes a
navigation map server 401, a power line 402, lamps 403-1 to 403-n,
and a VLC-enabled mobile terminal 406.
[0035] The navigation map server 401 stores data required for
providing a navigation function. Thus, the navigation map server
401 stores map data about the inside of a building, information
about the locations of the lamps 403-1 to 403-n, and the IDs of the
lamps 403-1 to 403-n, and communicates with each lamp by PLC. Also,
the navigation map server 401 receives destination information from
the mobile terminal 406 via a lamp, calculates a path to the
destination according to a predetermined navigation algorithm and
the map data, and provides the determined path to the mobile
terminal 406. Or the mobile terminal 406 can calculate the path
based on its data depending on system implementation.
[0036] The power line 402 is used as a medium for PLC between the
navigation map server 401 and the lamps 403-1 to 403-n. While
communications are conducted between the navigation map server 401
and the lamps 403-1 to 403-n by PLC in an exemplary embodiment of
the present invention, it can be further contemplated within the
scope of the present invention that the communications can be made
by other wired or wireless communication schemes.
[0037] The lamps 403-1 to 403-n are installed over the entire
building. They are not only used as lights but also
transmit/receive visible light signals 404 as visible light
communication devices. The lamps 403-1 to 403-n have their specific
IDs with which the mobile terminal 406 can locate itself and
maneuver to its final destination. The lamps 403-1 to 403-n can be
grouped according to their locations and IDs can be allocated on a
group basis. For example, the lights may be grouped by floor, or by
section of the building.
[0038] The mobile terminal 406 is equipped with a visible light
transceiver module for transmitting and receiving visible light
signals to and from the lamps 403-1 to 403-n. Also, the mobile
terminal 406 has a basic structure required to support the
navigation service, which may also include a display and an input
portion for entering user data.
[0039] A message exchange procedure between the mobile terminal and
the navigation server in the VLC navigation system according to an
exemplary embodiment of the present invention will be described
below.
[0040] FIG. 5 is a diagram illustrating a message exchange
procedure between network entities in the navigation system
according to an exemplary embodiment of the present invention.
[0041] Referring to FIG. 5, the navigation map server 401 transmits
a Provision message to mobile terminals via all the lamps 403
(i.e., Lamp1, Laim2 . . . Lamp n) within the network of the
navigation map server 401 in step 505. The Provision message
includes at least the following information.
TABLE-US-00001 TABLE 1 Terminal ID (broadcasting ID) Building ID
Version Destination list
[0042] Referring to Table 1, Terminal ID identifies the mobile
terminal. Particularly, Terminal ID is set to a broadcasting ID for
generating the message through all lamps 403. Building ID indicates
an ID of the building. Version provides information about a version
of data that can be changed during running the navigation system,
such as a destination list, map information, and information about
the positions and IDs of the lamps. Destination list is a list of
predetermined destinations within the building.
[0043] When the mobile terminal 406 receives the Provision message
and wants to receive the navigation service, it transmits a
Registration Request message to the navigation map server 401 in
step 510. The Registration Request message has at least the
following configuration (see Table 2).
TABLE-US-00002 TABLE 2 Terminal ID Building ID
[0044] In step 515, the navigation map server 401 replies to the
mobile terminal 406 with a Registration Response message configured
at least as follows (see Table 3).
TABLE-US-00003 TABLE 3 Terminal ID Building ID Map
[0045] In Table 3, MAP provides map information about an area where
the mobile terminal 406 is currently located.
[0046] The mobile terminal 406 then transmits a Map Request message
to the navigation map server 401 to indicate its destination
referring to Destination list set in the Provision message in step
520. The Map Request message has at least the following information
(see Table 4).
TABLE-US-00004 TABLE 4 Terminal ID Building ID Version
Destination
[0047] In Table 4, Destination indicates the desired
destination.
[0048] The navigation map server 401 calculates an optimum path to
the desired destination and transmits to the mobile terminal 460 in
step 525 a Map Response message including information about the
path. The Map Response message includes at least the following
information (see Table 5).
TABLE-US-00005 TABLE 5 Terminal ID Lamp ID Version Map Path
[0049] Referring to Table 5, Lamp ID provides the ID of a lamp
corresponding to the current area in which the mobile terminal 406
is located. Since the mobile terminal 406 can move toward the
destination during message transmission and reception, Lamp ID may
also include the IDs of lamps e around the local area which the
mobile terminal 406 can transmit and receive signals at its current
position and the IDs of lamps within a range where the mobile
terminal 406 is expected to move. The map may include information
about an entire map covering the current location of the mobile
terminal 406 to the destination. The path indicates at least one
path from the current location to the desired destination. In one
aspect of the invention, the path may be optimal with regard to the
time to traverse from the current location to the desired
destination. In another aspect, the path may be optimal with regard
to the distance between the current location and the desired
destination. In another aspect, the path may be selected based on a
combination of distance and time required to traverse from the
current location to the desired destination. As would be
recognized, the path may consider obstacles that may be between the
current location and the desired destination. For example, if the
desired destination is a location on a floor directly above the
user, then the path may consider taking a stairwell rather than
walking the length of the current floor to take an elevator to the
next floor.
[0050] In step 530, the mobile terminal 406 displays the map
information and the path to the destination based on the received
information. Then as the mobile terminal 406 starts to move along
the path, the navigation map server 401 transmits Lamp ID messages
to all lamps positioned along the path in which the mobile terminal
406 is moving in steps 535, 540 and 545. Each Lamp ID message
includes at least the following information (see Table 6).
TABLE-US-00006 TABLE 6 Terminal ID Lamp ID
[0051] The mobile terminal 406 can monitor its current location by
the Lamp ID messages and determine whether it gets out of the
path.
[0052] FIG. 6 is a diagram illustrating a message exchange
procedure between network entities in the navigation system
according to another exemplary embodiment of the present invention.
While the navigation map server 401 transmits all of necessary
information to the mobile terminal 406 at one time upon request of
the mobile terminal 406 in the first exemplary embodiment of the
present invention, in this exemplary embodiment, the map server 401
transmits segments of a necessary map sequentially to the mobile
terminal 406 in the second exemplary embodiment of the present
invention. Another feature of the second exemplary embodiment of
the present invention is that the area of the building is divided
into sections each having a predetermined size. The size of each
section may be arbitrarily determined and different.
[0053] Referring to FIG. 6, the navigation map server 401 transmits
a Provision message to mobile terminals via all the lamps 403
within the network of the navigation map server 401 in step 605.
The Provision message includes at least the following information
(see Table 7).
TABLE-US-00007 TABLE 7 Terminal ID (broadcasting ID) Building ID
Version Section list
[0054] Referring to Table 7, Terminal ID identifies the mobile
terminal. Particularly, Terminal ID is set to a broadcasting ID for
generating the message through all lamps 403. Building ID indicates
an ID of the building. Version provides information about a version
of data that can be changed during running the navigation system,
such as a destination list, map information, and information about
the positions and IDs of the lamps. Section list is a list of the
sections of the building.
[0055] When the particular mobile terminal 406 receives the
Provision message and wants to receive the navigation service, the
mobile terminal 406 transmits a Registration Request message to the
navigation map server 401 in step 610. The Registration Request
message has the following configuration (see Table 8).
TABLE-US-00008 TABLE 8 Terminal ID Building ID Lamp ID Section
index
[0056] In Table 8, Lamp ID indicates the ID of a lamp corresponding
to an area where the mobile terminal 406 is currently located.
Since the mobile terminal 406 can move toward the destination
during message transmission and reception, Lamp ID may include the
IDs of lamps of those lamps which the mobile terminal 406 can
transmit and receive signals at its current position and the IDs of
lamps within a range where the mobile terminal 406 is expected to
move. Section index indicates a section where the mobile terminal
is currently located.
[0057] In step 615, the navigation map server 401 replies to the
mobile terminal 406 with a Registration Response message configured
at least as follows (see Table 9).
TABLE-US-00009 TABLE 9 Terminal ID Building ID Version Section map
Current Location map
[0058] In Table 9, Section map provides entire map information
about the current section of the mobile terminal 406 and Current
Location map provides map information about the current area of the
mobile terminal 406.
[0059] The mobile terminal 406 then transmits a Map Request message
to the navigation map server 401 to indicate its destination in
step 620. The Map Request message has at least the following
information (see Table 10).
TABLE-US-00010 TABLE 10 Terminal ID Building ID Version
Destination
[0060] In Table 10, Destination indicates the desired
destination.
[0061] The navigation map server 401 calculates a path to the
desired destination and transmits a Map Response message including
information about the path to the mobile terminal 460 in step 625.
The Map Response message includes at least the following
information (see Table 11).
TABLE-US-00011 TABLE 11 Terminal ID Building ID Map Path
[0062] Referring to Table 11, Path indicates a path from the
current location to the destination and Map includes information
about a map covering the current location of the mobile terminal
406 to the destination. The map information can be transmitted in
segments over a plurality of times in steps 630 and 635.
[0063] In step 640, the mobile terminal 406 displays the map
information and the path to the destination based on the received
information. Then as the mobile terminal 406 starts to move along
the path the navigation map server 401 transmits Lamp ID messages
to all lamps positioned along the path in which the mobile terminal
406 is moving in steps 645, 650 and 655. Each Lamp ID message
includes at least the following information (see Table 12).
TABLE-US-00012 TABLE 12 Terminal ID Lamp ID
[0064] The mobile terminal 406 can monitor its current location by
the Lamp ID messages and determine whether the mobile terminal
deviates from the provided path.
[0065] During moving to the destination, the mobile terminal 406
periodically notifies the navigation map server 401 of its current
location by a Current Location Report message in step 660. The
Current Location Report message includes at least the following
information (see Table 13).
TABLE-US-00013 TABLE 13 Terminal ID Lamp ID
[0066] As is apparent from the above description, the present
invention advantageously provides a navigation function where GPS
reception is blocked by VLC between lamps installed in the
building, for example, to a mobile terminal and further defines
messages and a message exchange procedure between the mobile
terminal and a navigation server. Therefore, a user can be easily
guided to his destination by the navigation function in a
skyscraper or a large building.
[0067] The above-described methods according to the present
invention can be realized in hardware or as software or computer
code that can be stored in a recording medium such as a CD ROM, an
RAM, a floppy disk, a hard disk, or a magneto-optical disk or
downloaded over a network, so that the methods described herein can
be rendered in such software using a general purpose computer, or a
special processor or in programmable or dedicated hardware, such as
an ASIC or FPGA. As would be understood in the art, the computer,
the processor or the programmable hardware include memory
components, e.g., RAM, ROM, Flash, etc. that may store or receive
software or computer code that when accessed and executed by the
computer, processor or hardware implement the processing methods
described herein.
[0068] While the invention has been shown and described with
reference to certain exemplary embodiments of the present invention
thereof, it will be understood by those skilled in the art that
various changes in form and details may be made therein without
departing from the spirit and scope of the present invention as
defined by the appended claims and their equivalents.
* * * * *