U.S. patent number 9,271,323 [Application Number 14/222,131] was granted by the patent office on 2016-02-23 for apparatus and method for originating call by substitute communication network when originating call is barred.
This patent grant is currently assigned to Pantech Co., Ltd.. The grantee listed for this patent is Pantech Co., Ltd.. Invention is credited to Seung Woo Nam, Myeong Seon Seo, Sung Kyum Yoon.
United States Patent |
9,271,323 |
Nam , et al. |
February 23, 2016 |
Apparatus and method for originating call by substitute
communication network when originating call is barred
Abstract
A portable terminal and a method for originating a call through
a substituted network when originating a call is barred due to
overload of a first network is disclosed herein. A call may be
originated by automatically switching the communication mode of the
portable terminal from the first network such as an LTE network to
a second network such as a 3G network or a 2G network, when
originating a call is barred in the first network. The information
of the cell of the second network is searched from a second network
database stored in advance, which allows the time to search for a
cell and time to register in the second network decrease. The
searched cell with the highest power level may be selected and the
call is originated through the selected cell of the second
network.
Inventors: |
Nam; Seung Woo (Seoul,
KR), Seo; Myeong Seon (Seoul, KR), Yoon;
Sung Kyum (Seoul, KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
Pantech Co., Ltd. |
Seoul |
N/A |
KR |
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Assignee: |
Pantech Co., Ltd. (Seoul,
KR)
|
Family
ID: |
51654801 |
Appl.
No.: |
14/222,131 |
Filed: |
March 21, 2014 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20140302858 A1 |
Oct 9, 2014 |
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Foreign Application Priority Data
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Apr 5, 2013 [KR] |
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10-2013-0037674 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W
76/18 (20180201); H04W 48/02 (20130101) |
Current International
Class: |
H04W
40/00 (20090101); H04W 76/02 (20090101) |
Field of
Search: |
;455/445 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2009-268105 |
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Nov 2009 |
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JP |
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2010-141669 |
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Jun 2010 |
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JP |
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Primary Examiner: Karikari; Kwasi
Attorney, Agent or Firm: H.C. Park & Associates, PLC
Claims
What is claimed is:
1. A portable terminal for originating a call, the portable
terminal comprising: a reception unit to receive from a base
station a message barring originating a call in a first network; a
storage unit to store a first information, the first information
being information of one or more cells of a second network included
in a system information block (SIB) message and the storage unit
storing the first information in a second network database; an
input unit to receive a request to originate a call; a control unit
to select a cell in the storage unit with a power level higher than
a preset value if originating the call is barred in the first
network; and a transmission unit to originate the call in the
selected cell, wherein the control unit comprises: a communication
mode switching unit to switch a communication mode from the first
network to a second network if originating the call is barred in
the first network; a cell searching unit to search for cells in the
second network database and measure power levels of the searched
cells; and a cell selecting unit to select a searched cell if the
power level of the searched cell is higher than the preset
value.
2. The portable terminal of claim 1, wherein the storage unit
stores a second information, the second information being
information of one or more cells of a second network previously
used by the portable terminal.
3. The portable terminal of claim 1, wherein the first network is
an LTE network and the second network is one of a 3G network and a
2G network.
4. The portable terminal of claim 2, wherein the storage unit
stores the second information in the second network database, the
second network database comprising at least one of a 3G network
database and a 2G network database.
5. The portable terminal of claim 1, wherein the cell selecting
unit selects a searched cell with the highest power level if the
highest power level is higher than the preset value.
6. The portable terminal of claim 5, wherein, if the highest power
level is lower than the preset value, the cell searching unit
searches for cells of the second network not stored in the second
network database, and the cell selecting unit selects a searched
cell of the second network not stored in the second network
database if the power level of the searched cell is higher than the
preset value.
7. The portable terminal of claim 1, wherein the communication mode
switching unit switches from the second network to a different
second network if originating the call is barred in the second
network.
8. The portable terminal of claim 7, wherein the communication mode
switching unit switches the communication mode from the LTE network
to the 3G network if originating the call is barred in the LTE
network, and the communication mode switching unit switches the
communication mode from the 3G network to the 2G network if
originating a call is barred in the 3G network.
9. The portable terminal of claim 1, wherein the transmission unit
originates a circuit-switched (CS) call if a voice call is
requested and originates a packet-switched (PS) call if a data call
is requested.
10. A method to originate a call, the method comprising: receiving
from a base station a message barring originating a call in a first
network; storing a first information in a second network database,
the first information being information of one or more cells of a
second network included in a system information block (SIB)
message; receiving a request to originate a call; selecting a cell
among the cells corresponding to the stored first information with
a power level higher than a preset value if originating the call is
barred in the first network; and originating the call in the
selected cell, wherein selecting of the cell comprises: switching a
communication mode from the first network to a second network in
response to originating the call being barred in the first network;
searching for cells in the second network database and measuring
power levels of the searched cells; and selecting a searched cell
with a power level higher than the preset value.
11. The method of claim 10, further comprising storing a second
information, the second information being information of one or
more cells of a second network previously used by the portable
terminal.
12. The method of claim 11, further comprising storing the second
information in the second network database.
13. The method of claim 10, further comprising selecting a searched
cell with the highest power level if the highest power level is
higher than the preset value.
14. The method of claim 13, wherein, if the highest power level is
lower than the preset value, searching for cells in the second
network not stored in the second network database, and selecting a
searched cell in the second network not stored in the second
network database if the power level of the searched cell is higher
than a preset value.
15. The method of claim 10, further comprising switching the
communication mode from the second network to a different second
network if originating the call is barred in the second
network.
16. The method of claim 15, further comprising switching the
communication mode from the LTE network to the 3G network if
originating a call is barred in the LTE network, and switching the
communication mode from the 3G network to the 2G network if
originating a call is barred in the 3G network.
17. The method of claim 10, wherein the call is originated as a
circuit-switched (CS) call if a voice call is requested and
originated as a packet-switched (PS) call if a data call is
requested.
Description
CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority from and benefit under 35 U.S.C.
.sctn.119(a) of Korean Patent Application No. 10-2013-0037674,
filed on Apr. 5, 2013, in the Korean Intellectual Property Office,
which in its entirety is hereby incorporated by reference for all
purpose as if fully set forth herein.
BACKGROUND
1. Field
The following description relates to an apparatus and method for
originating a call by substitute communication network when
originating a call in a communication network is barred.
2. Discussions of Background
Long Term Evolution (LTE) is a term named after a next-generation
communication technology evolving from the third-generation (3G)
mobile communication. LTE is also referred to as 3.9 generation
(3.9G) mobile communication as a technology positioned between the
3G mobile communication represented by a wideband code division
multiple access (WCDMA), a code division multiple access (CDMA)
2000, etc. and the fourth-generation (4G) mobile communication, and
is one of leading candidates for the 4G mobile communication
technology.
Since an LTE network system is a data-dedicated network configured
by an all-IP network, the LTE network system supports only a packet
switching (PS) network but does not support a voice call that is
transmittable through a circuit switching (CS) network. Thus, in
order to support a voice service in the LTE network system,
additional technology is necessary. The Voice over Long Term
Evolution (VoLTE), acquired by profiling circuit switched fall back
(CSFB) and IP multimedia subsystem (IMS), is currently a popular
representative technology.
The VoLTE serves not only a data call but also a voice call through
a PS network. When a considerably high load is applied to an LTE
network base station to process large amounts of data calls, the
LTE network base station additionally needs to process voice calls.
Accordingly, in a region where many users are densely populated,
due to overload of the base station, users may not be able to use
not only a data call but also a voice call. For example, in a
region where many users are densely populated, such as a football
field or a concert hall, because one base station needs to process
a large amount of data transmitted from a large number of portable
terminals, calling services of some portable terminals may be
barred. In such a case, some users may not be able to use any call
originating services of their portable terminals.
The process in which originated calls are barred will be described
more specifically with reference to FIG. 1.
In operation S10, a portable terminal is registered in an LTE
network. After the portable terminal performs a cell search to
search for a communicable base station, the portable terminal and
the cell are synchronized with each other. After the
synchronization, the portable terminal acquires a physical layer
identity (ID) of the cell and searches for cell frame timing,
whereby the portable terminal may be registered in the LTE
network.
Thereafter, in operation S11, the portable terminal receives system
information block 2 (SIB2) messages at regular time intervals. The
SIB2 message includes cell information that is needed for a
portable terminal to appropriately operate within a corresponding
cell and necessary information for barring the call of a portable
terminal belonging to the cell.
In operation S12, if an originating call barring message is present
within the SIB2 message, the portable terminal stores the
originating call barring message. An originating call barring
message includes an ac-BarringInfo message, and the ac-BarringInfo
message includes ac-BarringForEmergency,
ac-BarringForMO-Signalling, and ac-BarringForMO-Data Information
Element (IE). In addition, ac-BarringForMO-Signalling and
ac-BarringForMO-Data IE include ac-BarringConfig IE, and
ac-BarringConfig IE includes sub-IEs ac-BarringFactor,
ac-BarringTime, and ac-BarringForSpecialAC. Here, ac-BarringFactor
has numbers (for example, 0, 0.05, 0.1, and 0.15 to 0.95) within a
range equal to or larger than zero and smaller than one, [0,1). In
addition, ac-BarringTime has a value between 4 seconds to 512
seconds. When the portable terminal receives the SIB2 message, all
the IE values within ac-BarringInfo are stored.
Thereafter, in operation S13, the portable terminal receives a
request for originating a call from a user input. For example, the
user inputs a text to the portable terminal and requests the
transmission for sending a message. The portable terminal
determines whether a VoLTE connection may be made to a
corresponding cell based on the user's request for originating a
call.
Specifically, in operation S14, the portable terminal checks
whether the ac-BarringForMO-Data IE is present within the
ac-BarringInfo message. When the ac-BarringForMO-Data IE is not
present, in operation S18 the portable terminal tries to originate
a call using the LTE cell.
However, in operation S15, if the ac-BarringForMO-Data IE is
present, an access classes (AC) value stored in a USIM of the
portable terminal is checked to determine whether the AC value has
a value in the range of 11 to 15. If the AC value has a value in
the range of 11 to 15, in operation S18 the portable terminal tries
to originate a call using the LTE cell.
On the other hand, in operation S16, if the AC value has a value in
the range of 0 to 9, the portable terminal checks if the difference
between a random value and the ac-BarringFactor value is greater
than zero. The random value represents a random number that is
generated in the range of 0 to 1 at the same probability and is
internally generated by the portable terminal.
If the difference in operation S16 is less than zero, in operation
S18 the portable terminal tries to originate a call in a
corresponding LTE cell. On the other hand, in operation S17 if the
difference in S16 is greater than zero, originating a call from the
portable terminal is barred in the corresponding cell. The barring
of the originating call continues for a predetermined time at a
specific probability until the ac-BarringForMO-Data IE is no longer
received through the SIB2 message.
As described above, if a large number of users are densely
populated within a specific cell, originating a call from a
portable terminal by an arbitrary user within the cell may be
barred. Since originating a call includes not only a data call but
also a voice call, an arbitrary user within a cell where
originating a call is barred may not use most of the data
communication services.
SUMMARY
Exemplary embodiments of the present invention provide an apparatus
and a method for originating a call in a cell in a second network
if originating a call in a first network is barred.
Additional features of the invention will be set forth in the
description which follow, and in part will be apparent from the
description, or may be learned by practice of the invention.
An exemplary embodiment of the present invention provides an
apparatus including a reception unit to receive from a base station
a message barring originating a call in a first network; a storage
unit to store a first information, the first information being
information of one or more cells of a second network included in a
system information block (SIB) message; an input unit to receive a
request to originate a call; a control unit to select a cell in the
storage unit with a power level higher than a preset value if
originating the call is barred in the first network; and a
transmission unit to originate the call in the selected cell.
An exemplary embodiment of the present invention provides a method
to originate a call including receiving from a base station a
message barring originating a call in a first network; storing a
first information, the first information being information of one
or more cells of a second network included in a system information
block (SIB) message; receiving a request to originate a call;
selecting a stored cell with a power level higher than a preset
value if originating the call is barred in the first network; and
originating the call in the selected cell.
An exemplary embodiment of the present invention provides an
apparatus including a reception unit to receive from a base station
a message barring originating a call in a first network; a storage
unit to store a first information, the first information being
information of one or more cells of a second network included in a
system information block (SIB) message; an input unit to receive a
request to originate a call; a communication mode switching unit to
switch a communication mode from the first network to the second
network if originating a call is barred in the first network; a
cell searching unit to search for cells in the second network
database and measure power levels of the searched cells; a cell
selecting unit to select a searched cell if the power level of the
searched cell is higher than a preset value; and a transmission
unit to originate the call in the selected cell.
An exemplary embodiment of the present invention provides a method
for including receiving from a base station a message barring
originating a call in a first network; storing a first information,
the first information being information of one or more cells of a
second network included in a system information block (SIB)
message; receiving a request to originate a call; switching a
communication mode from the first network to the second network if
originating a call is barred in the first network; searching for
cells in the second network database and measuring power levels of
the searched cells; selecting a searched cell if the power level of
the searched cell is higher than a preset value; and originating
the call in the selected cell.
It is to be understood that both the foregoing general description
and the following detailed description are exemplary and
explanatory and are intended to provide further explanation of the
invention as claimed. Other features and aspects will be apparent
from the following detailed description, the drawings and the
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are included to provide a further
understanding of the invention and are incorporated in and
constitute a part of this specification, illustrate embodiments of
the invention, and together with the description serve to explain
the principles of the invention.
FIG. 1 is flowchart illustrating a process in which originating a
call is barred for a portable terminal belonging to an LTE cell
according to the related art.
FIG. 2 is a structural diagram of a portable terminal according to
an exemplary embodiment of the present invention.
FIG. 3 is a conceptual diagram of a 2G network or 3G network
database stored in a storage unit according to an exemplary
embodiment of the present invention.
FIG. 4 is a schematic diagram that illustrates the relationship
between a portable terminal and a cell according to an exemplary
embodiment of the present invention.
FIG. 5 is a flowchart that illustrates a method for originating a
call through a second network according to an exemplary embodiment
of the present invention.
FIG. 6 is a flowchart that illustrates a method of determining
whether a call is originated through a substituted network
according to an exemplary embodiment of the present invention.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
The invention is described more fully hereinafter with reference to
the accompanying drawings, in which exemplary embodiments of the
invention are shown. This invention may, however, be embodied in
many different forms and should not be construed as limited to the
exemplary embodiments set forth herein. Rather, these exemplary
embodiments are provided so that this disclosure is thorough, and
will fully convey the scope of the invention to those skilled in
the art. In the drawings, the size and relative sizes of layers and
regions may be exaggerated for clarity. Like reference numerals in
the drawings denote like elements.
The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the present disclosure. As used herein, the singular forms "a",
"an" and "the" are intended to include the plural forms as well,
unless the context clearly indicates otherwise. Furthermore, the
use of the terms a, an, etc. does not denote a limitation of
quantity, but rather denotes the presence of at least one of the
referenced item. The use of the terms "first", "second", and the
like does not imply any particular order, but they are included to
identify individual elements. Moreover, the use of the terms first,
second, etc. does not denote any order or importance, but rather
the terms first, second, etc. are used to distinguish one element
from another. It will be further understood that the terms
"comprises" and/or "comprising", or "includes" and/or "including"
when used in this specification, specify the presence of stated
features, regions, integers, steps, operations, elements, and/or
components, but do not preclude the presence or addition of one or
more other features, regions, integers, steps, operations,
elements, components, and/or groups thereof. It will be understood
that for the purposes of this disclosure, "at least one of" will be
interpreted to mean any combination the enumerated elements
following the respective language, including combination of
multiples of the enumerated elements. For example, "at least one of
X, Y, and Z" will be construed to mean X only, Y only, Z only, or
any combination of two or more items X, Y, and Z (e.g. XYZ, XZ,
XZZ, YZ, X).
Hereinafter, an apparatus and a method for originating a call
through a second network when originating a call through a first
network is barred according to an exemplary embodiment of the
present invention will be described more detail with reference to
the drawings.
The 3G mobile communication is also referred to as IMT2000, and
includes technologies such as WCDMA, CDMA 2000, Time
Division--Synchronous Code Division Multiple Access (TD-SCDMA),
Digital Enhanced Cordless Telecommunications (DECT), Universal
Wireless Commun-136 (UWC-136), and Mobile Worldwide
Interoperability for Microwave Access (WiMAX). In addition, the
second-generation (2G) mobile communication includes technologies
such as Time Division Multiple Access (TDMA), Frequency Division
Multiple Access (FDMA), Code Division Multiple Access (CDMA),
Chemical Specialties Manufacturers Association (CSMA), Orthogonal
Frequency Division Multiple Access (OFDMA), Space Division Multiple
Access (SDMA), and Global System for Mobile communication (GSM).
Specifically, the 3G and 2G mobile communication technologies such
as WCDMA and GSM may be applied to an exemplary embodiment of the
present invention.
The LTE network system includes VoLTE, which is a communication
method acquired by profiling CSFB and IMS as discussed above. VoLTE
has a frequency bandwidth wider than that of the 3G voice phone
call and has superior call quality by using a high-quality voice
codec. Accordingly, a call connect time is markedly shorter than
that of 3G mobile communication system, and a voice phone call may
be switched to a video phone call. In addition, a photograph, a
video, position information, etc. may be easily shared during a
voice phone call.
FIG. 2 illustrates a portable terminal 100 including a reception
unit 110, a storage unit 120, a control unit 140, a communication
mode switching unit 150, a cell searching unit 160, a cell
selecting unit 170, an input unit 130, and a transmission unit 180,
according to an exemplary embodiment of the present invention.
The reception unit 110 receives messages, information, etc. that
are necessary to the communication of a portable terminal 100 from
a base station. In order to provide a communication service in an
arbitrary communication system, a physical channel for transmitting
common information such as the configuration of a cell is
necessary, and when a portable terminal 100 selects a specific
cell, the portable terminal 100 may perform communication after
receiving system information relating to the selected cell through
the physical channel. The system information is included in a
system information block (SIB) message and is transmitted through
the physical channel.
Hereinafter, the different types of SIB messages will be described
in more detail. An SIB1 message contains values of various timers,
counters, etc. and information relating to a core network (CN). An
SIB2 message contains an identifier of a URA (Universal Terrestrial
Radio Access Network (UTRAN) Registration Area) to which the cell
belongs, and the identifier includes an originating call barring
message. For example, the originating call barring message includes
an ac-BarringInfo message, and the ac-BarringInfo message includes
ac-BarringForEmergency, ac-BarringForMO-Signalling, and
ac-BarringForMO-Data IE. The ac-BarringForMO-Signalling and
ac-BarringForMO-Data IE include an ac-BarringConfig IE, and the
ac-BarringConfig IE includes sub-IEs, ac-BarringFactor,
ac-BarringTime, and ac-BarringForSpecialAC. An SIB3 message
contains information that is necessary to the selection of a cell
and the reselection of a cell. An SIB4 message contains information
that is necessary to the selection of a cell and the re-selection
of a cell to be used by the portable terminal 100 that is in the
connection mode. An SIB5 message contains information relating to
common channel configured in a corresponding cell. An SIB6 message
contains information relating to common channels of a corresponding
cell to be used by the portable terminal 100 that is in the
connection mode.
The storage unit 120 stores data for the operation of the portable
terminal 100, including information relating to a cell of a second
network, such as a 3G network and a 2G network that may substitute
for the LTE network. Specifically, when the reception unit 110
receives the SIB2 message in which an originating call barring
message is included, the storage unit 120 stores the originating
call barring message. In detail, if ac-BarringInfo and
ac-BarringForMO-Data are present within the SIB2 message, they may
be stored in the storage unit 120. In addition, if the cell
information of the second network adjacent to the location of the
portable terminal 100 is included within the SIB6 message received
by the reception unit 110, the storage unit 120 may store such cell
information. Furthermore, the storage unit 120 may store the
information of a cell used when the portable terminal 100 had been
previously registered in the second network. In detail, the
information of a cell that has been previously used may be the
information of a 3G network or a 2G network the portable terminal
had been previously registered in before being registered in the
LTE network.
The storage unit 120 may store the cell information supplied from
the SIB6 and the information of a cell that has been previously
used in a second network database to manage the cell information.
The second network database may include, for example, a 3G network
database and a 2G network database, and cell information
corresponding to each network is stored in the corresponding
database. Managing the databases relating to the cell information
of the second networks decreases time required to search for a cell
and time to register to a second network by increasing the
probability of finding a desired cell at the time of searching for
a cell in which a call may be originated while cells that may be
registered in the networks are separately managed.
FIG. 3 illustrates the conceptual structure of the second network
database including, for example, the 3G network database or the 2G
network database. As illustrated in FIG. 3, in the second network
database, a plurality of cell information pieces are formed as a
list. For example, the cell information pieces may be stored or
identified as into cell information included in the SIB6 message
and the information of cells used by the portable terminal 100 in
previously registered networks. The cell information stored in the
second network database is ranked in a descending order of the
power of each cell. For example, information of cell 1 and cell 2
included in the SIB6 message and information of cell 3 and cell 4
which are cell information of previously registered networks may be
stored as a list as illustrated in FIG. 3. If cell 1 has the
highest power level, followed by cell 2, cell 3, and cell 4, the
cell information of the corresponding cells may be stored in the
corresponding order. In FIG. 3, although the cell information
included in the SIB6 message is ranked at the top, aspects need not
be limited thereto such that the cell information included in the
SIB6 message may be ranked lower than some or all of the cells and,
for example, may be ranked at the bottom if it has the lowest power
level.
The power of a cell will be described in more detail with reference
to FIG. 4. Each cell includes the base station. For example, a cell
C1 includes a base station BS1, a cell C2 includes a base station
BS2, a cell C3 includes a base station BS3, and a cell C4 includes
a base station BS4. Each of the base stations BS1, BS2, BS3, and
BS4 propagates signals with, generally, a constant power level, and
accordingly, the range, on the ground, of influence of one cell may
be a circle shape. If a portable terminal T is located in a
specific location within the second cell C2, distances between the
portable terminal T and the base stations BS1, BS3, and BS4 of
cells C1, C3, and C4 may differ from each other. The power of a
cell influencing the portable terminal T decreases as the portable
terminal T is located farther from the base station of the cell,
and the power of the cell influencing the portable terminal T
increases as the portable terminal T is located closer to the base
station of the cell. As illustrated in FIG. 4, for example, the
distances from the portable terminal T to the base stations BS1,
BS2, BS3, and BS4 of the first cell C1, second cell C2, third cell
C3, and fourth cell C4, are defined as distance d1, distance d2,
distance d3, and distance d4 respectively. As shown in FIG. 4, the
distance d2 between the portable terminal T and the base station
BS2 of the cell C2 is the shortest followed by distances d3, d4,
and d1. Accordingly, the second cell C2 has the highest power level
for the portable terminal T, followed by the third cell C3, the
fourth cell C4, and the first cell C1.
As the power of a cell influencing a portable terminal 100 becomes
higher, the reception sensitivity of the portable terminal 100 is
improved, and each database of the storage unit 120 stores cell
information in order of the highest to lowest power level of the
cells. Accordingly, in the second network database, information of,
for example, the 3G network cell and the 2G network cell are listed
in a descending order of the power levels of the cells. Although
described sometimes as being separate, aspects need not be limited
thereto such that the 3G network cells and the 2G network cells and
other network cells may be included in one database and listed in a
descending order of power level of the cells regardless of to which
network or technology the cell belongs.
The input unit 130 in FIG. 2 receives a user input requesting for
originating a call. The input unit 130 may be configured in the
form such as a keypad, a button, or a touch screen. For example,
when a user clicks on a phone call icon displayed on the touch
screen, a request for originating a voice call is input to the
portable terminal 100.
The control unit 140 in FIG. 2 determines whether a call may be
originated in accordance with the input of the request for
originating a call. As described in S14, S15, and S16 illustrated
in FIG. 1, the control unit 140 determines whether there is an
originating call barring message, checks whether the AC value is
within a range in which a call may be originated, and determines
whether the difference between a random value and the
ac-BarringFactor is higher than zero, thereby determining whether
originating a call is barred. If originating a call is determined
to be barred, the control unit 140 bars originating a call for a
specified time.
If originating a call is barred, the control unit 140 may search
for a cell communicable through the second network. The control
unit 140 checks the communicability of the second network through
the communication mode switching unit 150, the cell searching unit
160, and the cell selecting unit 170, to be described in more
detail, and originates a call through the searched cell
communicable through the second network. Meanwhile, if a cell
communicable through the second network is not retrieved through a
search, the control unit 140 may return to the LTE network and
re-search for a communicable cell.
The communication mode switching unit 150 switches between the
communication modes of the LTE network and the second network such
as the 2G network or the 3G network in the portable terminal 100.
If originating a call is barred in the LTE network, the
communication mode switching unit 150 switches the communication
mode by selecting one of the 2G network and the 3G network. The
communication mode switching unit 150 switches the communication
mode to a different second network if a call may not be originated
in the selected second network. Specifically, the communication
mode switching unit 150 switches the communication mode first to a
3G network if originating a call is barred in the LTE network, and
switches the communication mode to a 2G network if communication in
the 3G network may not be performed. If communication may not be
performed through the second network as well, the communication
mode switching unit 150 switches the communication mode from the
substituted second network to the LTE network. The communication
mode switching unit 150 is controlled by the control unit 140 and
may be included in the control unit 140. Although aspects are
described as being part of the control unit 140, aspects need not
be limited thereto such that the communication mode switching unit
150 may be included separately or within other components or
units.
The cell searching unit 160 in FIG. 2 searches for a cell of the
second network, which is stored in the second network database, or
searches for a cell of the second network for the entire frequency
band and measures the power for the cell of the second network that
is retrieved through the search. The cell searching unit 160
measures the power for the cell of the second networks to connect
the portable terminal 100 to a cell having the highest power level
and reception sensitivity. Although the power may be measured for
the entire frequencies of all of the second networks, the cell
searching unit 160 first measures the power for a stored cell if
the cell information is stored in the second network database.
Although described as connecting the portable terminal 100 to a
cell having the highest power level and/or reception sensitivity,
aspects need not be limited thereto such that the portable terminal
100 may be connected to a cell having a sufficient power level
and/or reception sensitivity such as, for example, a power level
and/or a reception sensitivity greater than a threshold power level
and/or reception sensitivity.
Although the power levels may be measured for all of the
frequencies of the corresponding second networks, this may delay
the time for searching for a cell having a highest power level.
Thus, according to an exemplary embodiment of the present
invention, by using the second network database stored in advance,
the time required for searching for a cell may be shortened. In the
second network database, while the cell information is arranged in
the order of highest to lowest power levels, because the cell
information was stored before originating a call was barred, the
power levels of the cells may have changed according to the
movement of the portable terminal 100. Therefore, according to an
exemplary embodiment of the present invention, the power of the
cells stored in the second network database is measured again by
the cell searching unit 160 in the portable terminal 100.
The cell searching unit 160 supplies the result of the measurement
of the power to the cell selecting unit 170. If an appropriate cell
is not selected by the cell selecting unit 170, such result is sent
back from the cell selecting unit 170 to the cell searching unit,
and the power is measured for all of the frequency bands of the
corresponding 3G and 2G second network. The resulting measurement
for all of the frequency bands is supplied to the cell selecting
unit 170 again.
The cell selecting unit 170 receives the information relating to
the power level of each cell from the cell searching unit 160,
selects a cell having a power level equal to or higher than a
preset level, and sends the result to the control unit 140. The
preset level is a value that is stored in the cell selecting unit
170 in advance and is a value designated such that the portable
terminal 100 may smoothly perform communication in the second
network. If a cell having a level equal to or higher than the
preset level is not retrieved, the cell selecting unit 170 sends
the result back to the cell searching unit 160.
In addition, in a case where there is no cell selected in the
selected second network, the cell selecting unit 170 sends such
result back to the control unit 140, and the control unit 140
controls the communication mode switching unit 150 to search for a
cell in another second network. For example, if the power is
measured for all of the frequency bands by the cell searching unit
160 in the 3G network, and there is no cell selected by the cell
selecting unit 170, the control unit 140 controls the communication
mode switching unit 150 to switch from the 3G network mode to the
2G network mode. After switching to the 2G network mode, the cell
searching unit 160 and the cell selecting unit 170 may search for
and retrieve a cell that is communicable through the 2G
network.
If a cell is selected in the second network, the transmission unit
180 originates a call that has been barred in the first network
using the cell in the second network. During the transmission, the
transmission unit 180 originates a call differently when the user
requests a circuit-switched (CS) call and a packet-switched (PS)
call. For example, if the user requests the portable terminal 100
for a phone call, the transmission unit 180 originates the call in
the CS mode. On the other hand, if the user requests the portable
terminal 100 for the transmission of a message, the transmission
unit 180 originates the call in the PS mode.
Hereinafter, a method for originating a call through the second
network, when originating a call is barred in the first network,
according to an exemplary embodiment of the present invention will
be described more specifically with reference to FIG. 5.
In operation S100, the portable terminal 100 in FIG. 2 is in the
state of being registered in the LTE network and is in a state in
which an SIB2 message including an originating call barring message
is received. For example, in a case where the portable terminal 100
supports the VoLTE communication method, in a state in which the
portable terminal 100 is registered in the IMS, many people may be
populated in an area such as a football field or a concert hall. In
such a case, since data overload may occur in the corresponding
base station, a user may receive a message barring originating a
call.
In operation S101, the user inputs a request for originating a call
to the portable terminal 100, and, in operation S102, a message
indicates that originating a call from the portable terminal 100 is
barred for a specific barring time.
Accordingly, in operation S103, the portable terminal 100
determines whether a call may be originated through the second
network such as the 3G network or the 2G network. Specifically, the
portable terminal 100 searches for a cell communicable in the 3G
network or the 2G network and determines that a call may be
originated if a communicable cell is retrieved.
In operation S104, if a communicable cell is retrieved in any one
of the selected cells in the 3G network and the 2G network, the
portable terminal 100 performs a registration process for the
selected network.
In operation S105, the transmission unit 180 in FIG. 2 of the
portable terminal 100 determines whether the call requested to be
originated is a CS call. If the requested call is a CS call, in
operation S106 the call is originated in the CS mode. On the other
hand, if the requested call is not a CS call, in operation S107 the
call is originated in the PS mode.
In operation S108, after originating the call is completed, the
control unit 140 in FIG. 2 of the portable terminal 100 is returned
to the LTE network and performs re-registration.
However, in operation S103, if a call may not be originated through
the 3G network or the 2G network, in operation S109 the portable
terminal 100 searches for a cell in which a call may be originated
in the LTE network again.
At this time, in operation S110, if there is a cell in which a call
may be originated in the LTE network that has been searched again,
the portable terminal 100 originates a call through the LTE
network. On the other hand, in operation S11, if there is no cell
in which a call may be originated, there are no more communication
networks for substitution, and a state in which originating a call
failed is maintained.
Hereinafter, operation S103 in FIG. 5 is described in more detail
with reference to FIG. 6 accordingly to an exemplary embodiment of
the present invention.
In operation S200, the portable terminal 100 holds the requested
call originated.
The reception unit 110 in FIG. 2 receives an SIB6 message in
operation S201 and determines whether information relating to a
cell in an area adjacent to the portable terminal 100 is included
in the SIB6 message in operation S202.
If information relating to an adjacent cell is included in the SIB6
message, the communication mode switching unit 150 in FIG. 2
switches the LTE mode of the portable terminal 100 to the 3G mode
in operation S203.
Thereafter, in operation S204 the cell searching unit 160 in FIG.
2, first, measures the power of the cell stored in the 3G network
database by referring to the 3G network database within the storage
unit 120.
In operation S205, the cell searching unit 160 provides the cell
selecting unit 170 in FIG. 2 with the measurement result, and the
cell selecting unit 170 determines whether there is a cell of which
the power is measured through the measurement result. If cell
information is included in the 3G network database, there is a
measured cell. On the other hand, if cell information is not
included in the 3G network database, there is no measured cell.
In operation S206, if there is a cell of which the power is
measured, the cell selecting unit 170 searches for a cell having a
power level that is equal to or higher than a preset level where
the preset level, as described above, represents a power level for
which communication may be smoothly performed in the 3G
network.
In operation S207, among the cells of which the power levels are
measured, if there is a cell having a power level equal to or
higher than the preset level, the cell selecting unit 170 selects
the cell of the 3G network, and the control unit 140 performs 3G
network registration through the transmission unit 180.
However, in operation S208, if there is no cell having a power
level that is equal to or higher than the preset level, the cell
selecting unit 170 sends back the result to the cell searching unit
160, and the cell searching unit 160 determines whether the power
measurement has been performed for all frequency bands.
In operation S209, if the power measurement has not been performed
for all frequency bands, the cell searching unit 160 measures power
for all frequency bands of the 3G network. Thereafter, the cell
searching unit 160 provides the cell selecting unit 170 with the
measurement result again, and the cell selecting unit 170 goes
through operation S206 again.
Meanwhile, if it is determined that there are a plurality of cells
having power levels equal to or higher than the preset level, the
cell selecting unit 170 may select a cell having a highest power
level among the plurality of cells.
In operation S210, if no cell having a power level equal to or
higher than the preset level is retrieved through a search in the
3G network through operation S206 and operation S208, the cell
selecting unit 170 sends back the result to the control unit 140,
and the control unit 140 switches the 3G mode to the 2G mode by
controlling the communication mode switching unit 150. In addition,
in operation S202, if information relating to an adjacent cell has
not been delivered from the SIB6 message, the control unit 140
switches the communication mode of the portable terminal 100 from
the LTE mode to the 2G mode.
Thereafter, in operation S211, the cell searching unit 160 measures
power for cells included in the 2G network database. Operations
S212 to S215 performed thereafter are the same as operations S205
to S209 described above except that the cells of the 2G network are
searched, whereby a cell in which a call may be originated is
searched. In other words, if there is a cell having a power level
equal to or higher than the preset level among the cells included
in the 2G network database or cells included in all frequency bands
of the 2G network, the cell selecting unit 170 selects the cell of
the 2G network, and the control unit 140 performs 2G network
registration through the transmission unit 180.
However, in operation S217, if a cell having a power level equal to
or higher than the preset level is not found in the 2G network
database or in all frequency bands of the 2G network, the portable
terminal 100 fails to originate a call through the 3G network or 2G
network. For example, in a case where the portable terminal 100
originates a call in a region in which only the LTE service is
supported, even when the power is measured for all the frequency
bands of the 2G network or 3G network, a cell in which a call may
be originated is not retrieved through a search. In such a case,
like in operation S109 illustrated in FIG. 5, the portable terminal
100 returns to the first network, and an LTE cell in which a call
may be originated is searched again.
According to an exemplary embodiment of the present invention as
described above, as a method for decreasing the data overload
phenomenon of an LTE base station in an LTE service in which a
voice call is transmitted as data, a call may be originated by
switching from the first network in which originating a call is
barred to the second network such as the 3G network or the 2G
network. Conventionally, if a call may not be originated in the
first network, the user tries to originate a call by manually
changing the setting of the portable terminal to the second network
mode. However, according to an exemplary embodiment of the present
invention, a user's convenience in using a portable terminal may be
improved by the portable terminal automatically switching between
the communication modes when originating a call is barred. In
addition, by using the cell information of the database stored in
advance in the portable terminal when cells of the second network
are searched, the time required for the registration in the second
network may be shortened.
The exemplary embodiments according to the present invention may be
recorded in non-transitory computer-readable media including
program instructions to implement various operations embodied by a
computer. The media may also include, alone or in combination with
the program instructions, data files, data structures, and the
like. The media and program instructions may be those specially
designed and constructed for the purposes of the present invention,
or they may be of the kind well-known and available to those having
skill in the computer software arts. Examples of non-transitory
computer-readable media include magnetic media such as hard disks,
floppy disks, and magnetic tape; optical media such as CD ROM disks
and DVD; magneto-optical media such as floptical disks; and
hardware devices that are specially configured to store and perform
program instructions, such as read-only memory (ROM), random access
memory (RAM), flash memory, and the like. Examples of program
instructions include both machine code, such as produced by a
compiler, and files containing higher level code that may be
executed by the computer using an interpreter. The described
hardware devices may be configured to act as one or more software
modules in order to perform the operations of the above-described
embodiments of the present invention.
It will be apparent to those skilled in the art that various
modifications and variation can be made in the present invention
without departing from the spirit or scope of the invention. Thus,
it is intended that the present invention cover the modifications
and variations of this invention provided they come within the
scope of the appended claims and their equivalents.
* * * * *