U.S. patent application number 11/732789 was filed with the patent office on 2007-08-16 for base station and mobile terminal for location detection, and location detecting method.
Invention is credited to Hyun Lee, Hyun-Seo Oh, Chang-Sub Shin.
Application Number | 20070188382 11/732789 |
Document ID | / |
Family ID | 34651355 |
Filed Date | 2007-08-16 |
United States Patent
Application |
20070188382 |
Kind Code |
A1 |
Shin; Chang-Sub ; et
al. |
August 16, 2007 |
Base station and mobile terminal for location detection, and
location detecting method
Abstract
Disclosed are a base station and a mobile terminal for location
detection, and a location detecting method. The base station in
which a plurality of antennas having RF modules are installed
transmits a signal including location information of each of the
antennas to the mobile terminal. The mobile terminal carries out
location detection by selectively using location information
received from a GPS receiver or location information received from
a DSRC transceiver. The base station and mobile terminal for
location detection can perform location detection with high
accuracy using the existing DSRC service. Thus, the base station
and mobile terminal can carry out location detection having an
error of approximately 10 m in downtown areas or buildings.
Inventors: |
Shin; Chang-Sub;
(Daejeon-city, KR) ; Oh; Hyun-Seo; (Daejeon-city,
KR) ; Lee; Hyun; (Seoul, KR) |
Correspondence
Address: |
BLAKELY SOKOLOFF TAYLOR & ZAFMAN
1279 OAKMEAD PARKWAY
SUNNYVALE
CA
94085-4040
US
|
Family ID: |
34651355 |
Appl. No.: |
11/732789 |
Filed: |
April 3, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10882525 |
Jun 30, 2004 |
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11732789 |
Apr 3, 2007 |
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Current U.S.
Class: |
342/386 |
Current CPC
Class: |
G01S 5/0263 20130101;
G01S 1/08 20130101 |
Class at
Publication: |
342/386 |
International
Class: |
G01S 1/08 20060101
G01S001/08 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 10, 2003 |
KR |
10-2003-0089733 |
Claims
1. A mobile terminal for location detection, comprising: a GPS
receiver for detecting a location of a base station using a GPS; a
DSRC transceiver for extracting location information from a beacon
signal transmitted from the base station in an area where location
detection is impossible through the GPS receiver to detect the
location of the base station; and a central processing unit for
extracting location detection data through the GPS receiver or the
DSRC transceiver and displaying it on a map.
2. A location detecting method comprising: a) detecting a beacon
signal including location information, transmitted from a base
station, through a DSRC module installed in a mobile terminal; b)
when the beacon signal is detected, extracting the location
information from the beacon signal to use it as location detection
data; and c) when the beacon signal is not detected, using location
detection data detected using a GPS.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to and the benefit of Korea
Patent Application No. 2003-89733 filed on Dec. 10, 2003 in the
Korean Intellectual Property Office, the entire content of which is
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] (a) Field of the Invention
[0003] The present invention relates to a base station and a mobile
terminal for location detection, and a location detecting method.
More specifically, the present invention relates to a base station
and a mobile terminal for location detection, and a location
detecting method using a GPS technique and dedicated short range
communication (DSRC).
[0004] (b) Description of the Related Art
[0005] Methods for detecting locations of mobile terminals include
a technique that decides a location of a base station having a cell
ID as a location of a mobile terminal, an AOA (Arrival Of Angle)
method by which a base station determines a location of a mobile
terminal through a direction angle of a signal transmitted from the
mobile terminal, and a TDOA (Time Difference Of Arrival) method
that detects a location of a mobile terminal using a time
difference of arrival of a signal between the mobile terminal and a
base station. The location detecting methods further include a
technique that detects a location of a mobile terminal through a
combination of the AOA and TDOA methods, RF fingerprinting that
compares an RF characteristic value of a signal received from a
mobile terminal with a value stored in a database to detect a
location of the mobile terminal, a technique using a global
positioning system (GPS), and a network-assisted GPS method.
[0006] In the method using a GPS, a mobile terminal receives signal
information of the GPS such that a location of the mobile terminal
is detected. This method is easy to use and can detect a relatively
accurate location of the mobile terminal outdoors. However, it
consumes a large amount of electric power, requires a long time to
first fix (TTFF), and has many restrictions on location detection
indoors and in downtown areas due to interference of multiple paths
and an insufficient number of visible satellites.
[0007] With the network-assisted GPS method, which is one method
for solving the problems of the GPS method, a mobile terminal can
be provided with assistant data required for obtaining a list of
satellites and satellite signals from a base station to reduce the
time to first fix and additionally receive a correction signal.
[0008] The method using a cell ID can easily detect a location of a
mobile terminal without modifying the existing equipment. However,
this method has a problem in that accuracy of a location detecting
result varies with a cell diameter. For example, a macro-call has
an error of approximately 20 Km in diameter, a micro-cell has an
error of 0.5 to 1 Km in diameter, and a pico-cell has an error of
about 50 m in diameter.
[0009] With the AOA method, a base station measures a direction
angle of a signal transmitted from a mobile terminal using an array
antenna to detect a location of the mobile terminal. However, this
technique has a large location error because it is difficult to
secure LOS (Line Of Sight) due to a multi-path in downtown areas.
Furthermore, since the AOA method requires an array antenna, the
mobile terminal has difficulty in using the method.
[0010] The TDOA method calculates a distance between a mobile
terminal and a base station using a one-way signal arrival time
between the mobile terminal and base station. With this method, a
final location of the mobile terminal is detected from intersecting
points of circles having three base stations at their centers.
However, this technique has poor location accuracy.
[0011] The RF fingerprinting is an auxiliary location detecting
method used to detect a location of a mobile terminal in downtown
areas or inside buildings where the method using a GPS is difficult
to use. This technique should continuously update a database
according to a geographical environment and a channel state. In
addition, its location detection performance is deteriorated due to
a plurality of mobile terminals.
[0012] As described above, conventional location detecting methods
are divided into techniques using a GPS and techniques not using
GPS.
[0013] The techniques using a GPS have geographical restrictions
that require LOS to be secured, need a long time to first fix, and
consume a large amount of electric power, although they can detect
a location of a mobile terminal relatively easily.
[0014] To solve the aforementioned problems, the network assisted
GPS method allows a mobile terminal to receive information required
for GPS location detection from the nearest base station. Thus,
this method can reduce time and power consumption required for
location detection. A network based location detecting method is
used in areas where GPS location detection is impossible, such as
downtown areas or indoor areas. However, the network assisted GPS
method has a problem in that a location detection error is
increased depending on a cell area when a location of a mobile
terminal is detected using a network.
[0015] Among the techniques not using GPS, the AOA method can be
used only in a base station because it requires an array antenna.
Furthermore, a location detection error is increased due to a
multi-path effect in downtown areas. As a distance between a mobile
terminal and the base station is increased, the location detection
error is also increased.
[0016] The TDOA method generates an error caused by locations of
base stations, an error due to a multi-path in downtown areas, an
error caused by a near-far problem due to a high reception signal
from a near base station, and so on.
[0017] Methods other than the above-described techniques also have
restrictions on location detection with high accuracy.
SUMMARY OF THE INVENTION
[0018] It is an advantage of the present invention to provide a
base station and a mobile terminal for location detection, and a
location detecting method for accurately detecting a location of a
mobile terminal by selectively using a GPS technique and DSRC.
[0019] To accomplish the object of the present invention, a base
station in which a plurality of antennas having RF modules are
installed transmits a signal including location information of each
of the antennas to a mobile terminal. The mobile terminal carries
out location detection by selectively using location information
received from a GPS receiver or location information received from
a DSRC transceiver.
[0020] In one aspect of the present invention, a base station for
location detection includes a location information generator for
generating location information of each of a plurality of antennas
arranged at specific intervals; a central processing unit for
preventing the antennas from interfering with one another,
processing data transmitted and received between the base station
and a mobile terminal, and generating a periodic beacon signal and
transmitting it to the mobile terminal; a location information
processor for loading the location information of each of the
antennas generated by the location information generator in a
header of the beacon signal and transmitting the beacon signal to a
corresponding antenna; and a modulating/demodulating unit for
converting data transmitted and received between the central
processing unit and the antennas into an analog or digital
signal.
[0021] The base station further includes a plurality of
multiplexers for simultaneously outputting the beacon signal
transmitted from the central processing unit through the
modulating/demodulating unit to the antennas.
[0022] The base station further includes a buffer for receiving
data transmitted from the mobile terminal through the plurality of
antennas and delivering the data to the modulating/demodulating
unit.
[0023] Preferably, a cell diameter of each of the antennas is 10 to
15 m.
[0024] In another aspect of the present invention, a mobile
terminal for location detection includes a GPS receiver for
detecting a location of a base station using a GPS; a DSRC
transceiver for extracting location information from a beacon
signal transmitted from the base station in an area where location
detection is impossible through the GPS receiver to detect the
location of the base station; and a central processing unit for
extracting location detection data through the GPS receiver or the
DSRC transceiver, and displaying it on a map.
[0025] In another aspect of the present invention, a location
detecting method comprises a) generating location information of
each of a plurality of antennas arranged at specific intervals and
loading the location information in a header of a beacon signal to
be transmitted to a mobile terminal; and b) synchronizing the
antennas and simultaneously transmitting the beacon signal to the
antennas.
[0026] The step a) comprises carrying out output cell planning such
that the antennas maintain the specific intervals in order to
remove interference of the antenna cells.
[0027] In another aspect of the present invention, a location
detecting method comprises a) detecting a beacon signal including
location information, transmitted from a base station, through a
DSRC module installed in a mobile terminal; b) when the beacon
signal is detected, extracting the location information from the
beacon signal to use as location detection data; and c) when the
beacon signal is not detected, using location detection data
detected using a GPS.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The accompanying drawings, which are incorporated in and
constitute a part of the specification, illustrate an embodiment of
the invention, and, together with the description, serve to explain
the principles of the invention:
[0029] FIG. 1 shows a configuration of a base station for location
detection according to a first embodiment of the present
invention;
[0030] FIG. 2 shows a configuration for downward communication of
the base station for location detection according to the first
embodiment of the present invention;
[0031] FIG. 3 shows a configuration for upward communication of the
base station for location detection according to the first
embodiment of the present invention;
[0032] FIG. 4 shows a configuration of a mobile terminal for
location detection according to a second embodiment of the present
invention;
[0033] FIG. 5 shows a format of a communication frame generated in
a base station of the present invention; and
[0034] FIG. 6 is a flow chart of a location detecting method
executed by a mobile terminal of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0035] In the following detailed description, only the preferred
embodiment of the invention has been shown and described, simply by
way of illustration of the best mode contemplated by the
inventor(s) of carrying out the invention. As will be realized, the
invention is capable of modification in various obvious respects,
all without departing from the invention. Accordingly, the drawings
and description are to be regarded as illustrative in nature, and
not restrictive.
[0036] First, a base station for location detection according to a
first embodiment of the present invention is explained in detail
with reference to FIGS. 1, 2, and 3. FIG. 1 shows a configuration
of a base station for location detection according to a first
embodiment of the present invention, FIG. 2 shows a configuration
for downward communication of the base station for location
detection according to the first embodiment of the present
invention, and FIG. 3 shows a configuration for upward
communication of the base station for location detection according
to the first embodiment of the present invention.
[0037] Referring to FIGS. 1, 2, and 3, the base station 100
according to the first embodiment of the invention includes a
plurality of antennas 101 each of which has an RF module, a
location information generator 110, a central processing unit 120,
a location information processor 130, a modulating/demodulating
unit 140, a memory 150, a plurality of multiplexers 160, and a
buffer 170.
[0038] A cell diameter of each of the antennas 101 is set to 10 to
15 m, such that accuracy of location information in each cell is
improved.
[0039] The location information generator 110 generates location
information of each of the antennas 101. The central processing
unit 120 prevents the plurality of antennas from interfering with
one another, and processes data transmitted and received between
the base station and a mobile terminal. In addition, the central
processing unit 120 generates a periodic beacon signal and sends it
to the mobile terminal.
[0040] The location information processor 130 loads the location
information of each antenna, generated by the location information
generator 120, in the header of the beacon signal and transmits the
beacon signal to the antennas simultaneously. The
modulating/demodulating unit 140 converts data transmitted and
received between the central processing unit 120 and the plurality
of antennas 101 into a digital or analog signal, and transmits it
to the multiplexers 160 or central processing unit 120.
[0041] The multiplexers 160 simultaneously transmit the beacon
signal including the location information of the antennas, sent
from the central processing unit 120 and location information
processor 130, to the antennas. The buffer 170 receives data
transmitted from the mobile terminal through the plurality of
antennas and delivers the data to the modulating/demodulating unit
140. The memory 150 stores data transmitted to/from the central
processing unit 120.
[0042] FIG. 4 shows a configuration of a mobile terminal for
location detection according to a second embodiment of the present
invention.
[0043] Referring to FIG. 4, the mobile terminal 200 includes
antennas 201 respectively having RF modules, a DSRC transceiver
210, a GPS receiver 220, a central processing unit 230, an IC card
interface 240, and a memory 250.
[0044] The mobile terminal extracts location information from the
header of the beacon signal transmitted from the base station in an
area where location detection is impossible through the GPS
receiver 220 to detect a location of the base station.
[0045] The GPS receiver 220 detects the location of the base
station using a GPS. When the DRSC transceiver 210 does not detect
the beacon signal, the central processing unit 230 calls location
detection data from the GPS receiver 220. The IC card interface 240
is interfaced to an IC card used for communication. The IC card
stores personal information and processes codes, and has high
security. The memory 250 stores data input/output to/from the
mobile terminal 200.
[0046] Operations of the base station and mobile terminal according
to the present invention are described below with reference to
FIGS. 5 and 6.
[0047] FIG. 5 shows a format of a communication frame generated in
the base station of the present invention, and FIG. 6 is a flow
chart of a location detecting method executed by the mobile
terminal of the present invention.
[0048] The plurality of antennas respectively having RF modules are
arranged at specific intervals in the base station 100. The
location information generator 110 generates location information
of each of the antennas. The location information is included in a
header frame of the beacon signal that is periodically generated by
the central processing unit 120 of the base station 100 and
transmitted to the mobile terminal 200. At this time, the central
processing unit performs cell planning such that the antennas
maintain specific intervals or switch adjacent antenna cells to
transmit or receive signals in order to prevent interference of the
antennas. Furthermore, the central processing unit 120 synchronizes
the antennas in order to simultaneously output the beacon signal to
the antennas through the multiplexers 160.
[0049] The base station 100 receives data from the mobile terminal
200 through the buffer 170, similar to a base station having a
single antenna.
[0050] Referring to FIG. 6, when the mobile terminal 200 is turned
on, the mobile terminal 200 detects the beacon signal transmitted
from the base station 100 through the DSRC transceiver 210 in step
S1. When the beacon signal is detected, the central processing unit
230 of the mobile terminal 200 extracts the location information
included in the beacon signal to use it as location detection data
in step S2. When the beacon signal is not detected, the central
processing unit 230 obtains location detection data through the GPS
receiver 220 in step S3.
[0051] In step S4, the central processing unit displays a current
location of the base station on a map using the location detection
data obtained through the DSRC transceiver 210 or GPS receiver 220.
The location detection data can be used for various application
services including a real-time transportation information providing
service, a broadcasting service, a real-time circulation service,
and so on. In particular, the location detection data can be used
for a car navigation system.
[0052] When a predetermined period of time has passed after the
location detection is completed, the central processing unit 230
repeatedly extracts location detection data using the DSRC
transceiver 210 or GPS receiver 220 in step S5. The DSRC
transceiver 210 can be used for conventional short range radio
communication as well as location detection.
[0053] As described above, the base station and mobile terminal for
location detection, and a location detecting method of the present
invention, can perform location detection with high accuracy using
the existing DSRC service. Thus, a system for detecting a location
can be constructed at a low cost and easily extended. Furthermore,
the present invention can carry out location detection having an
error of approximately 10 m in downtown areas or buildings.
[0054] While this invention has been described in connection with
what is presently considered to be the most practical and preferred
embodiment, it is to be understood that the invention is not
limited to the disclosed embodiments, but, on the contrary, is
intended to cover various modifications and equivalent arrangements
included within the spirit and scope of the appended claims.
* * * * *