U.S. patent application number 14/711028 was filed with the patent office on 2016-07-28 for multi-rat mobile communication devices and methods for network selection.
The applicant listed for this patent is MediaTek Inc.. Invention is credited to Chi-Ju CHANG, Yu-Ting CHEN, Yen-Ku LIU, Tao-Sheng OU.
Application Number | 20160219501 14/711028 |
Document ID | / |
Family ID | 53404349 |
Filed Date | 2016-07-28 |
United States Patent
Application |
20160219501 |
Kind Code |
A1 |
CHANG; Chi-Ju ; et
al. |
July 28, 2016 |
MULTI-RAT MOBILE COMMUNICATION DEVICES AND METHODS FOR NETWORK
SELECTION
Abstract
A mobile communication device supporting a plurality of Radio
Access Technologies (RATs) and a plurality of radio frequencies is
provided. In the mobile communication device, a Baseband processor
is configured to schedule the plurality of RATs and the plurality
of radio frequencies in pairs in an order for a Public Land Mobile
Network (PLMN) selection procedure, and determine one of the pairs
and repeat the determined pair in the order of the pairs during the
PLMN selection procedure.
Inventors: |
CHANG; Chi-Ju; (Taipei City,
TW) ; OU; Tao-Sheng; (Taoyuan City, TW) ;
CHEN; Yu-Ting; (Meishan Township, TW) ; LIU;
Yen-Ku; (New Taipei City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MediaTek Inc. |
Hsin-Chu |
|
TW |
|
|
Family ID: |
53404349 |
Appl. No.: |
14/711028 |
Filed: |
May 13, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62108156 |
Jan 27, 2015 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 48/18 20130101;
H04W 88/06 20130101 |
International
Class: |
H04W 48/18 20060101
H04W048/18; H04W 88/06 20060101 H04W088/06 |
Claims
1. A mobile communication device supporting a plurality of Radio
Access Technologies (RATs) and a plurality of radio frequencies,
comprising: a Baseband processor configured to schedule the
plurality of RATs and the plurality of radio frequencies in pairs
in an order for a Public Land Mobile Network (PLMN) selection
procedure, and determine one of the pairs and repeat the determined
pair in the order of the pairs during the PLMN selection procedure,
wherein the determined pair is determined according to one of the
following features of each of the pairs: whether a RAT and a radio
frequency of a pair is a serving RAT and a serving frequency;
whether a RAT and a radio frequency of a pair appears in neighbor
information from a System Information Broadcast (SIB) or
measurement configuration; whether a RAT and a radio frequency of a
pair appears in a frequency list from a subscriber identity card
coupled in or to the mobile communication device; and a priority
level of a PLMN to which a RAT and a radio frequency of a pair
belong.
2. The mobile communication device of claim 1, wherein the
determined pair is repeated during the PLMN selection procedure
when a predetermined number of the other pairs have been scanned,
or when a predetermined period of time has elapsed since the last
repeat of the determined pair.
3. (canceled)
4. The mobile communication device of claim 1, wherein the PLMN
selection procedure is initiated in response to a power-on of the
mobile communication device or in response to the mobile
communication device being out of service.
5. The mobile communication device of claim 1, wherein the Baseband
processor is further configured to determine a list of a plurality
of PLMNs, and during the PLMN selection procedure, the PLMNs are
selected one at a time from the top of the list and the pairs are
scanned in the order with the determined pair repeated therein for
each selected PLMN.
6. The mobile communication device of claim 1, wherein, each time
one of the PLMNs is selected, the Baseband processor is further
configured to determine whether one or more of the pairs in the
order belongs to a PLMN other than the selected PLMN, and the one
or more of the pairs are skipped during the PLMN selection
procedure for the selected PLMN.
7. A method for network selection by a mobile communication device
supporting a plurality of Radio Access Technologies (RATs) and a
plurality of radio frequencies, comprising: scheduling the
plurality of RATs and the plurality of radio frequencies in pairs
in an order for a Public Land Mobile Network (PLMN) selection
procedure; and determining one of the pairs and repeating the
determined pair in the order of the pairs during the PLMN selection
procedure; wherein the determined pair is determined according to
one of the following features of each of the pairs: whether a RAT
and a radio frequency of a pair is a serving RAT and a serving
frequency; whether a RAT and a radio frequency of a pair appears in
neighbor information from a System Information Broadcast (SIB) or
measurement configuration; whether a RAT and a radio frequency of a
pair appears in a frequency list from a subscriber identity card
coupled in or to the mobile communication device; and a priority
level of a PLMN to which a RAT and a radio frequency of a pair
belong.
8. The method of claim 7, wherein the determined pair is repeated
during the PLMN selection procedure when a predetermined number of
the other pairs have been scanned, or when a predetermined period
of time has elapsed since the last repeat of the determined
pair.
9. (canceled)
10. The method of claim 7, wherein the determined pair is repeated
during the PLMN selection procedure when a predetermined number of
the other pairs have been scanned, or when a predetermined period
of time has elapsed since the last repeat of the determined
pair.
11. The method of claim 7, further comprising determining a list of
a plurality of PLMNs, wherein during the PLMN selection procedure,
the PLMNs are selected one at a time from the top of the list and
the pairs are scanned in the order with the determined pair
repeated therein for the selected PLMN.
12. The method of claim 11, further comprising: each time one of
the PLMNs is selected, determining whether one or more of the pairs
in the order belongs to a PLMN other than the selected PLMN,
wherein the one or more of the pairs are skipped during the PLMN
selection procedure for the selected PLMN.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority of U.S. Provisional
Application No. 62/108,156, filed on Jan. 27, 2015, the entirety of
which is incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention generally relates to wireless communication
technologies, and more particularly, to methods for network
selection by mobile communication devices supporting a plurality of
Radio Access Technologies (RATs) and a plurality of radio
frequencies.
[0004] 2. Description of the Related Art
[0005] With growing demand for ubiquitous computing and networking,
various Radio Access Technologies (RATs) have been developed, such
as the Global System for Mobile communications (GSM) technology,
General Packet Radio Service (GPRS) technology, Enhanced Data rates
for Global Evolution (EDGE) technology, Wideband Code Division
Multiple Access (W-CDMA) technology, High Speed Packet Access
(HSPA) technology, Interim Standard 95 (IS-95) technology, Code
Division Multiple Access 2000 (CDMA2000) technology, CDMA2000
1.times. Evolution-Data Optimized or Evolution-Data (1.times.
EV-DO) technology, Time Division-Synchronous Code Division Multiple
Access (TD-SCDMA) technology, Worldwide Interoperability for
Microwave Access (WiMAX) technology, Long Term Evolution (LTE)
technology, Time-Division LTE (TD-LTE) technology, LTE-Advanced
(LTE-A) technology, and others.
[0006] Generally, a mobile phone only supports one RAT for
providing users with the flexibility of mobile communications at
all times via the supported RAT. However, due to the complexity of
various network deployments, so-called multi-RAT mobile phones have
been developed, which generally support two or more RATs and radio
frequencies, and select one of the RATs for obtaining mobile
services. Since multi-RAT mobile phones support multiple RATs and
radio frequencies, the Public Land Mobile Network (PLMN) selection
procedure will inevitably take a long time to complete a full scan
for all of the supported RATs on each supported radio frequency.
This may create an unfavorable situation where a multi-RAT mobile
phone enters an area with very poor signal quality only for a short
time (e.g., passing through a tunnel). For example, once the
multi-RAT mobile phone detects that the signal coverage has been
lost, the PLMN selection procedure will be performed for a full
scan. Later, even if the multi-RAT mobile phone swiftly enters an
area with signal coverage of those that have been scanned in the
early stage of the full scan, it will still continue the full scan
with the un-scanned RATs and radio frequencies and cannot regain
normal services from the available area using the scanned RAT and
radio frequency. The delay for regaining normal services is
expected to get worse especially when the number of supported RATs
and radio frequencies increases, and the longer the delay is, the
higher the chance of a service breakup (e.g., TCP/IP-based
application).
[0007] Therefore, it is desirable to have a more sophisticated way
of network selection that can reduce the time to obtain/regain
normal services.
BRIEF SUMMARY OF THE INVENTION
[0008] In one aspect of the invention, a mobile communication
device supporting a plurality of RATs and a plurality of radio
frequencies is provided. The mobile communication device comprises
a Baseband processor which is configured to schedule a plurality of
RATs and a plurality of radio frequencies in pairs in an order for
a Public Land Mobile Network (PLMN) selection procedure, and
determine one of the pairs and repeat the determined pair in the
order of the pairs during the PLMN selection procedure.
[0009] In another aspect of the invention, a method for network
selection by a mobile communication device supporting a plurality
of RATs and a plurality of radio frequencies is provided. The
method comprises the steps of: scheduling the plurality of RATs and
the plurality of radio frequencies in pairs in an order for a PLMN
selection procedure; and determining one of the pairs and repeating
the determined pair in the order of the pairs during the PLMN
selection procedure.
[0010] Other aspects and features of the present invention will
become apparent to those with ordinarily skill in the art upon
review of the following descriptions of specific embodiments of the
mobile communication devices and the methods for network
selection.
BRIEF DESCRIPTION OF DRAWINGS
[0011] The invention can be more fully understood by reading the
subsequent detailed description and examples with references made
to the accompanying drawings, wherein:
[0012] FIG. 1 is a block diagram illustrating a wireless
communications environment according to an embodiment of the
invention;
[0013] FIG. 2 is a block diagram illustrating the mobile
communication device 110 according to an embodiment of the
invention;
[0014] FIG. 3 is a flow chart illustrating the method for network
selection by a mobile communication device according to an
embodiment of the invention;
[0015] FIG. 4 is a schematic diagram illustrating the scheduling
list of pairs of RATs and radio frequencies with more than one
repeated pair according to an embodiment of the invention; and
[0016] FIG. 5 is a flow chart illustrating the method for network
selection by a mobile communication device according to another
embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0017] The following description is of the best-contemplated mode
of carrying out the invention. This description is made for the
purpose of illustrating the general principles of the invention and
should not be taken in a limiting sense. It should be understood
that the embodiments may be realized in software, hardware,
firmware, or any combination thereof.
[0018] FIG. 1 is a block diagram illustrating a wireless
communications environment according to an embodiment of the
invention. The wireless communications environment 100 comprises a
mobile communication device 110, and a plurality of service
networks 121.about.123 and 131.about.133, wherein the service
networks 121.about.123 belong to the PLMN 120, and the service
networks 131.about.133 belong to the PLMN 130. That is, the service
networks 121.about.123 are deployed by one operator, and the
service networks 131.about.133 are deployed by another operator.
Each of the service networks 121.about.123 supports a respective
RAT in one or more particular radio frequencies. Likewise, each of
the service networks 131.about.133 supports a respective RAT in one
or more particular radio frequencies. Specifically, the service
network 121 is a GSM network, the service network 122 is a WCDMA
network, and the service network 123 is an LTE network. The service
network 131 is an IS-95 network, the service network 132 is a
CDMA2000 network, and the service network 133 is a TD-LTE
network.
[0019] The mobile communication device 110 supports a plurality of
RATs and radio frequencies, including the RATs and radio
frequencies utilized by the service networks 121.about.123 and
131.about.133. The mobile communication device 110 may wirelessly
communicate with one of the service networks 121.about.123 and
131.about.133 for obtaining mobile services, including
Circuit-Switched (CS) and/or Packet-Switched (PS) services, wherein
the CS services may include voice call services, and Short Message
Service (SMS), etc., and the PS services may include data services,
such as e-mail transmission, web browsing, file upload/download,
instant messaging, streaming video, or others. For example, the
mobile communication device 110 may be a multi-RAT mobile device,
such as a mobile phone, panel PC, or notebook PC, etc.
Alternatively, the mobile communication device 110 may be an
external data card for a computer host, notebook, or panel PC to
obtain mobile services.
[0020] FIG. 2 is a block diagram illustrating the mobile
communication device 110 according to an embodiment of the
invention. The mobile communication device 110 comprises a Radio
Frequency (RF) device 10, a Baseband chip 20, a display device 30,
an input device 40, and a storage device 50, wherein the RF device
10, the display device 30, the input device 40, and the storage
device 50 are coupled to the Baseband chip 20. The Baseband chip 20
comprises a processor 21, such as a Micro-Control Unit (MCU),
Digital Signal Processor (DSP), or the like, for controlling the
communications between the subscriber identity card and the RF
device 10, sending a series of frame data (e.g. representing text
messages, graphics, images or others) to the display device 30,
receiving signals from the input device 40, and storing and
retrieving data to and from the storage device 50. Most
importantly, the processor 21 coordinates the aforementioned
operations of the RF device 10, the display device 30, the input
device 40, and the storage device 50 for performing the method for
network selection.
[0021] The subscriber identity card may be provided in compliance
with the specification of one or more of the RATs utilized by the
service networks 121.about.123 and 131.about.133, and is used to
store a frequency list (which may also be referred to as a stored
list of frequencies), and subscriber information, including
subscriber information and preset PLMNs (such as Registered PLMN
(RPLMN), Home PLMN (HPLMN), and Equivalent PLMN (EPLMN)). For
example, the subscriber identity card may be a Subscriber Identity
Module (SIM) card for the service network 121 being a GSM network
or the service network 122 being a WCDMA network, or the subscriber
identity card may be a Universal SIM (USIM) card for the service
network 122 being a WCDMA network or the service network 123 being
an LTE network, or the subscriber identity card may be a User
Identity Module (UIM) for the service network 131 being an IS-95
network, or the subscriber identity card may be a Removable UIM
(RUIM) for the service network 132 being a CDMA2000 network.
Alternatively, the mobile communication device 110 may need more
than one subscriber identity card or the subscriber identity card
is a dual-mode subscriber identity card, for holding more than one
set of stored information and subscriber information, which allows
the mobile communication device 110 to wirelessly communicate with
more than one of the service networks 121.about.123 and
131.about.133 at the same time.
[0022] In one embodiment, the Baseband chip 20 may further comprise
one interface (not shown) to handle the connection to the
subscriber identity card. In another embodiment, the mobile
communication device 110 may further comprise a card controller
(not shown) coupled or connected between the Baseband chip 20 and
the subscriber identity card. The card controller is responsible
for powering the subscriber identity card with a voltage level
according to the requirements thereof by a Power Management
Integrated Chip (PMIC) and a battery, wherein the voltage level for
the subscriber identity card is determined during initiation. The
Baseband chip 20 may read/write data from/to the subscriber
identity card via the card controller. In addition, the card
controller selectively transfers clocks, resets, and/or data
signals to the subscriber identity card according to instructions
issued by the Baseband chip 20. Alternatively, the stored
information and subscriber information may be written directly into
the mobile communication device 110, without the need for any
socket to insert any subscriber identity card, or the stored and
subscriber information may be provided by a virtual subscriber
identity card stored in the storage device 50, and the invention is
not limited thereto.
[0023] Additionally, the Baseband chip 20 may further contain other
hardware components to perform baseband signal processing,
including Analog-to-Digital Conversion (ADC)/Digital-to-Analog
Conversion (DAC), gain adjusting, modulation/demodulation,
encoding/decoding, and so on. The RF device 10 may receive RF
wireless signals via the antenna, convert the received RF wireless
signals to baseband signals, which are processed by the Baseband
chip 20, or receive baseband signals from the Baseband chip 20 and
convert the received baseband signals to RF wireless signals, which
are later transmitted via the antenna. The RF device 10 may also
contain multiple hardware devices to perform radio frequency
conversion. For example, the RF device 10 may comprise a mixer to
multiply the baseband signals with a carrier oscillated in the
radio frequency of the supported RATs, wherein the radio frequency
may be 900 MHz, 1800 MHz or 1900 MHz utilized in GSM/GPRS/EDGE
technology, or may be 900 MHz, 1900 MHz or 2100 MHz utilized in
WCDMA technology, or may be 900 MHz, 2100 MHz, or 2.6 GHz utilized
in LTE/LTE-A/TD-LTE technology, or others, depending on the RAT in
use.
[0024] The display device 30 may be a Liquid-Crystal Display (LCD),
Light-Emitting Diode (LED) display, or Electronic Paper Display
(EPD), etc., for providing a display function. Alternatively, the
display device 30 may further comprise one or more touch sensors
disposed thereon or thereunder for sensing touches, contacts, or
approximations of objects, such as fingers or styluses.
[0025] The input device 40 may comprise one or more buttons, a
keyboard, a mouse, a touch pad, a video camera, a microphone,
and/or a speaker, etc., serving as the Man-Machine Interface (MMI)
for interaction with users.
[0026] The storage device 50 may be a memory, such as a FLASH
memory or a Non-volatile Random Access Memory (NVRAM), or a
magnetic storage device, such as a hard disk or a magnetic tape, or
an optical disc, or any combination thereof for storing
communication data for the Baseband chip 20 and/or storing
subscriber data read from the subscriber identity card.
[0027] It should be understood that the components described in the
embodiment of FIG. 2 are for illustrative purposes only and are not
intended to limit the scope of the present application.
[0028] FIG. 3 is a flow chart illustrating the method for network
selection by a mobile communication device according to an
embodiment of the invention. In this embodiment, the mobile
communication device is a multi-RAT mobile phone which supports a
plurality of RATs and radio frequencies. To begin, the mobile
communication device schedules the plurality of RATs and the
plurality of radio frequencies in pairs in an order for a PLMN
selection procedure (step S310). Specifically, the PLMN selection
procedure is initiated in response to a power-on of the mobile
communication device or in response to the mobile communication
device being out of service.
[0029] Subsequently, the mobile communication device determines one
of the pairs and repeats the determined pair in the order of the
pairs during the PLMN selection procedure (step S320).
Specifically, the determined pair is determined according to one of
the following features of each of the pairs: 1) whether a RAT and a
radio frequency of a pair is a serving RAT and a serving frequency;
2) whether a RAT and a radio frequency of a pair appears in
neighbor information from a System Information Broadcast (SIB) or
measurement configuration; 3) whether a RAT and a radio frequency
of a pair appears in a frequency list from a subscriber identity
card coupled in or to the mobile communication device; and 4) a
priority level of a PLMN to which a RAT and a radio frequency of a
pair belong. For example, each pair may be assigned a weighting
value according to the features mentioned above, and the pairs are
scheduled in the order of their corresponding weighting values,
wherein the pair with a weighting value greater than a
predetermined threshold may be determined to be repeated.
[0030] In one embodiment, the determined pair is repeated during
the PLMN selection procedure when a predetermined number of the
other pairs have been scanned. For example, the mobile
communication device may use a counter to count the number of pairs
that have been scanned since the last repeat of the determined
pair, and repeat the determined pair when the counter reaches the
predetermined number. In another embodiment, the determined pair is
repeated during the PLMN selection procedure when a predetermined
period of time has elapsed since the last repeat of the determined
pair. For example, the mobile communication device may use a timer
to count the predetermined period of time from the last repeat of
the determined pair, and repeat the determined pair when the timer
expires.
[0031] FIG. 4 is a schematic diagram illustrating the scheduling
list of pairs of RATs and radio frequencies with more than one
repeated pair according to an embodiment of the invention. As shown
in the upper half of FIG. 4, the supported RATs and radio
frequencies are paired up and scheduled from left to right
according to the priority levels of their corresponding PLMNs. In
another embodiment, the pairs of RATs and radio frequencies may be
scheduled according to other features of the pairs as described in
the embodiment of FIG. 3. Specifically, the mobile communication
device may maintain a prioritized list of the PLMNs, which arranges
the PLMNs according to their priority levels. In this embodiment,
the RPLMN has the highest priority level, and the HPLMN has the
next highest priority level.
[0032] Among all pairs, the pairs belonging to the RPLMN are
determined to be the most important target for network selection.
As shown in the lower half of FIG. 4, the scheduling list is
rearranged to repeat the first 3 pairs. Specifically, the first
pair is repeated after a predetermined number of subsequent pairs
or after a predetermined number of times has elapsed, the second
pair is repeated after a predetermined number of pairs subsequent
to the repeated first pair or after a predetermined number of times
has elapsed since the repeated first pair, and the third pair is
repeated after a predetermined number of pairs subsequent to the
repeated second pair or after a predetermined number of times has
elapsed since the repeated second pair. That is, the first 3 pairs
will be rescanned every once in a while to increase the chance of
obtaining/regaining services from the RPLMN.
[0033] FIG. 5 is a flow chart illustrating the method for network
selection by a mobile communication device according to another
embodiment of the invention. In this embodiment, the mobile
communication device is a multi-RAT mobile phone which supports a
plurality of RATs and radio frequencies. To begin, the mobile
communication device is powered on or detects an out-of-service
situation (step S501), and then initiates a PLMN selection
procedure. Specifically, during the PLMN selection procedure, the
mobile communication device first selects one PLMN from the top of
a prioritized list of a plurality of PLMNs (step S502). That is,
the PLMN with the highest priority level is selected.
[0034] The prioritized list arranges the PLMNs according to their
priority levels, wherein the priority levels may be in compliance
with the 3rd Generation Partnership Project (3GPP) Technical
Specification (TS) 23.122, V8.7.0. For example, the RPLMN or EPLMN
may have the first priority level, the HPLMN or Equivalent Home
PLMN (EHPLMN) may have the second priority level, the PLMNs in the
"User Controlled PLMN selector with Access Technology" data file
stored in the subscriber identity card may have the third priority
level, the PLMNs in the "Operator Controlled PLMN selector with
Access Technology" data file stored in the subscriber identity card
may have the fourth priority level, the PLMNs with high received
signal quality may have the fifth priority level, and other PLMNs
may have the sixth priority level and arranged in descending order
of received signal quality.
[0035] Next, the mobile communication device determines whether any
cell belonging to the selected PLMN has been found previously
during the PLMN selection procedure (step S503). If no cell
belonging to the selected PLMN has been found previously, the
mobile communication device selects one pair of RAT and radio
frequency from the top of the scheduling list of a plurality of
pairs of RATs and radio frequencies, and then scans the selected
pair of RAT and radio frequency (step S504). In another embodiment,
when selecting a pair from the scheduling list, the mobile
communication device may determine whether one or more of the pairs
in the scheduling list belong to a PLMN other than the selected
PLMN, and if so, the pairs belonging to a different PLMN are
skipped.
[0036] Subsequently, the mobile communication device determines
whether any cell belonging to the selected PLMN has been found with
the selected pair (step S505). If no cell belonging to the selected
PLMN has been found with the selected pair, the mobile
communication device determines whether all pairs in the scheduling
list have been scanned (step S506), and if not, the method returns
to step S504. Otherwise, if all pairs in the scheduling list are
scanned, the search for the selected PLMN is determined to be
complete and the method continues to step S507.
[0037] In step S507, the mobile communication device determines
whether all PLMNs in the priority list have been searched, and if
so, the method ends. Otherwise, if there is any unsearched PLMN in
the priority list, the method returns to step S502.
[0038] Subsequent to step S505, if a cell belonging to the selected
PLMN has been found with the selected pair, the mobile
communication device performs a registration procedure on the found
cell (step S508), and then determines whether full services can be
obtained from the selected PLMN (step S509). If full services can
be obtained, the method ends. Otherwise, if full services cannot be
obtained, the method continues to step S507. Please note that the
detailed description of the registration procedure is omitted
herein since it is beyond the scope of the invention.
[0039] Subsequent to step S503, if a cell belonging to the selected
PLMN has been found previously, the method continues to step
S508.
[0040] While the invention has been described by way of example and
in terms of preferred embodiment, it is to be understood that the
invention is not limited thereto. Those who are skilled in this
technology can still make various alterations and modifications
without departing from the scope and spirit of this invention. For
example, the method of FIGS. 3 and 5 may be implemented in program
code stored in a machine-readable storage medium, such as a
magnetic tape, semiconductor, magnetic disk, optical disc (e.g.,
CD-ROM, DVD-ROM, etc.), or others, which is loaded and executed by
the Baseband processor of a mobile communication device. Therefore,
the scope of the present invention shall be defined and protected
by the following claims and their equivalents.
* * * * *