U.S. patent application number 13/613538 was filed with the patent office on 2013-02-28 for call forwarding methods and apparatus for mobile communication devices which operate in wwans and wlans.
This patent application is currently assigned to RESEARCH IN MOTION LIMITED. The applicant listed for this patent is Vytautas Robertas Kezys, Mihal Lazaridis, Thomas Charles Nagy, Ingo W. Weigele. Invention is credited to Vytautas Robertas Kezys, Mihal Lazaridis, Thomas Charles Nagy, Ingo W. Weigele.
Application Number | 20130051281 13/613538 |
Document ID | / |
Family ID | 39668569 |
Filed Date | 2013-02-28 |
United States Patent
Application |
20130051281 |
Kind Code |
A1 |
Lazaridis; Mihal ; et
al. |
February 28, 2013 |
CALL FORWARDING METHODS AND APPARATUS FOR MOBILE COMMUNICATION
DEVICES WHICH OPERATE IN WWANS AND WLANS
Abstract
A mobile device has a telephone number for calling the mobile
device in a cellular network, and a SIP identity for calling the
mobile device in the WLAN. The mobile device operates in the WLAN
to receive voice call services, where voice calls directed to the
telephone number are call forwarded to the SIP identity.
Subsequently, the mobile device operates in the cellular network to
receive the voice call services. The mobile device sends, via the
cellular network, a message for cancelling the call forwarding of
voice calls. The mobile device also sends, via a data communication
service of the cellular network, a message for call forwarding
voice calls directed to the SIP identity of the mobile device to
the telephone number of the mobile device operating in the cellular
network.
Inventors: |
Lazaridis; Mihal; (Waterloo,
CA) ; Nagy; Thomas Charles; (Waterloo, CA) ;
Kezys; Vytautas Robertas; (Hamilton, CA) ; Weigele;
Ingo W.; (Waterloo, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Lazaridis; Mihal
Nagy; Thomas Charles
Kezys; Vytautas Robertas
Weigele; Ingo W. |
Waterloo
Waterloo
Hamilton
Waterloo |
|
CA
CA
CA
CA |
|
|
Assignee: |
RESEARCH IN MOTION LIMITED
Waterloo
CA
|
Family ID: |
39668569 |
Appl. No.: |
13/613538 |
Filed: |
September 13, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13311015 |
Dec 5, 2011 |
8331340 |
|
|
13613538 |
|
|
|
|
11669692 |
Jan 31, 2007 |
8085742 |
|
|
13311015 |
|
|
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Current U.S.
Class: |
370/259 |
Current CPC
Class: |
H04M 3/42246 20130101;
H04W 88/06 20130101; H04W 92/02 20130101; H04W 84/12 20130101; H04M
3/54 20130101; H04M 7/006 20130101; H04W 4/16 20130101 |
Class at
Publication: |
370/259 |
International
Class: |
H04W 4/16 20090101
H04W004/16 |
Claims
1-9. (canceled)
10. A method for use by a mobile device in facilitating voice calls
via a wireless local area network (WLAN) or a cellular network, the
mobile device having a telephone number for calling the mobile
device in the cellular network and a SIP identity for calling the
mobile device in the WLAN, the method comprising: operating in the
WLAN to receive voice call services, where voice calls directed to
the telephone number of the mobile device are call forwarded to the
SIP identity of the mobile device operating in the WLAN; sending,
via the cellular network, a message for cancelling the call
forwarding of voice calls directed to the telephone number of the
mobile device to the SIP identity of the mobile device; sending,
via a data communication service of the cellular network, a message
for call forwarding voice calls directed to the SIP identity of the
mobile device to the telephone number of the mobile device
operating in the cellular network; and operating in the cellular
network to receive the voice call services.
11. The method of claim 10 wherein while operating in the cellular
network to receive the voice call services, voice calls directed to
the SIP identity the mobile device are call forwarded to the
telephone number of the mobile device operating in the cellular
network.
12. The method of claim 10, wherein the data communication service
comprises a packet data service.
13. The method of claim 10, wherein the WLAN comprises an IEEE
802.11-based wireless network.
14. The method of claim 10, wherein an association is made between
the SIP identity and a home location register (HLR) of the cellular
network for the forwarding of voice calls.
15. The method of claim 10, wherein an association is made between
the cellular telephone number and a location server for the
forwarding of voice calls directed to the SIP identity of the
mobile device to the telephone number of the mobile device
operating in the cellular network.
16. The method of claim 10, wherein the sending of the message for
call forwarding voice calls further comprises sending the message
for call forwarding to a location server.
17. The method of claim 10, wherein the sending of the message for
call forwarding voice calls further comprises sending the message
to a location server in the WLAN.
18. A computer program product, comprising: a non-transitory
computer readable medium; computer instructions stored in the
non-transitory computer readable medium; the computer instructions
being executable by one or more processors of a mobile device for
facilitating voice calls via a wireless local area network (WLAN)
or a cellular network, the mobile device having a telephone number
for calling the mobile device in the cellular network and a SIP
identity for calling the mobile device in the WLAN, the computer
instructions being executable for: operating the mobile device in
the WLAN to receive voice call services, where voice calls directed
to the telephone number of the mobile device are call forwarded to
the SIP identity of the mobile device operating in the WLAN;
sending, via the cellular network, a message for cancelling the
call forwarding of voice calls directed to the telephone number of
the mobile device to the SIP identity of the mobile device;
sending, via a data communication service of the cellular network,
a message for call forwarding voice calls directed to the SIP
identity of the mobile device to the telephone number of the mobile
device operating in the cellular network; and operating the mobile
device in the cellular network to receive the voice call
services.
19. A mobile device, comprising: a first wireless transceiver
portion configured for wireless communications via a wireless local
area network (WLAN); a second wireless transceiver portion
configured for wireless communications via a cellular network; one
or more processors coupled to the first and the second wireless
transceiver portions; the one or more processors being configured
to process voice calls of the mobile device via the WLAN or the
cellular network, the mobile device having a telephone number for
calling the mobile device in the cellular network and a SIP
identity for calling the mobile device in the WLAN, the one or more
processors being further configured for: operating the mobile
device in the WLAN to receive voice call services, where voice
calls directed to the telephone number of the mobile device are
call forwarded to the SIP identity of the mobile device operating
in the WLAN; sending, through the second wireless transceiver
portion via the cellular network, a message for cancelling the call
forwarding of voice calls directed to the telephone number of the
mobile device to the SIP identity of the mobile device; sending,
through the second wireless transceiver portion via a data
communication service of the cellular network, a message for call
forwarding voice calls directed to the SIP identity of the mobile
device to the telephone number of the mobile device operating in
the cellular network; and operating the mobile device in the
cellular network to receive the voice call services,
20. The mobile device of claim 19, wherein while operating in the
cellular network to receive the voice call services, voice calls
directed to the SIP identity the mobile device are call forwarded
to the telephone number o the mobile device operating in the
cellular network.
21. The mobile device of claim 19, wherein the data communication
service comprises a packet data service.
22. The mobile device of claim 19, wherein the WLAN comprises an
IEEE 802.11-based wireless network.
23. The mobile device of claim 19, wherein an association is made
between the SIP identity and a home location register (HLR) of the
cellular network for the forwarding of voice calls.
24. The mobile device of claim 19, wherein an association is made
between the cellular telephone number and a location server for the
forwarding of voice calls directed to the SIP identity of the
mobile device to the telephone number of the mobile device
operating in the cellular network.
25. The mobile device of claim 19, wherein the one or more
processors are configured for sending of the message for call
forwarding voice calls by sending the message for call forwarding
to a location server.
26. The mobile device of claim 19, wherein the one or more
processors are configured for sending the message for call
forwarding voice calls by sending the message to a location server
in the WLAN.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of and claims
priority to U.S. non-provisional patent application having
application Ser. No. 13/311,015 and filing date of 5 Dec. 2011, now
U.S. Pat. No. ______, which is a continuation of and claims
priority to U.S. non-provisional patent application having
application Ser. No. 11/669,692 and filing date of 31 Jan. 2007,
now U.S. Pat. No. 8,085,742, each application being hereby
incorporated by reference herein.
BACKGROUND
[0002] 1. Field Of The Technology
[0003] The present application relates generally to mobile
communication devices which operate in both wireless wide area
networks (WWANs) such as cellular telecommunication networks and
wireless local area networks (WLANs) such as 802.11-based
networks.
[0004] 2. Description Of The Related Art
[0005] A mobile communication device may be designed to operate on
two different types of heterogeneous wireless networks, such as a
wireless local area network (WLAN) (e.g. 802.11-based wireless
network) and a wireless wide area network (WWAN) (e.g. a cellular
telecommunications network). Two different wireless transceiver
portions of the mobile device are utilized for communications in
the WLAN and WWAN. The mobile device switches operations between
the WLAN and the WWAN depending on its location and/or other
factors.
[0006] Each wireless transceiver portion of the mobile device is
associated with a unique identification number (e.g. telephone
number, IP address, session initiation protocol (SIP) address,
etc.) so that the mobile device may receive voice calls through
both WLAN and WWAN. When the mobile device operates in the WLAN, it
is reachable by its WLAN identification number in the WLAN but
otherwise it may be out-of-service with the WWAN and not be
reachable with use of the WWAN identification number. On the other
hand, when the mobile device operates in the WWAN, it is reachable
by its WWAN identification number in the WWAN but it otherwise may
be out-of-service with the WLAN and not be reachable with use of
the WLAN identification number.
[0007] Accordingly, what are needed are methods and apparatus to
improve the the reachability techniques for such dual mode or
multi-mode mobile communication terminals.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Embodiments of the present application will now be
described, by way of example only, with reference to the attached
figures. Same reference numerals are used in different figures to
denote similar elements.
[0009] FIG. 1 is a schematic block diagram illustrating the basic
components of a mobile terminal operating in a wireless
communication system which includes a wireless wide area network
(e.g. a cellular telecommunications network) as well as a wireless
local area network (WLAN) (e.g. an 802.11-based network);
[0010] FIG. 2 is a block diagram which illustrates a communication
system which includes a plurality of mobile terminals which operate
in the WLAN;
[0011] FIG. 3 is a more detailed schematic diagram of the mobile
terminals of FIG. 1, namely, a mobile station of the preferred
embodiment;
[0012] FIGS. 4-7 are top down views showing a mobile terminal
moving in accordance with a travel path through coverage regions of
the WWAN and the WLANs; and
[0013] FIG. 8 is a flowchart which helps describe call forwarding
methods of the mobile terminal according to the present
application.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] Methods and apparatus for use by a mobile communication
device in facilitating voice calls through a wireless local area
network (WLAN) and a wireless wide area network (WWAN) are
disclosed. When switching communication operations from a WLAN
coverage region of the WLAN to a WWAN coverage region of the WWAN,
the mobile device causes a message for forwarding voice calls to a
WWAN identification number of the mobile device to be transmitted
through the WLAN. The mobile device also causes a message for
cancelling the forwarding of voice calls to a WLAN identification
number of the mobile device to be transmitted through the WWAN.
When switching communication operations from the WWAN coverage
region of the WWAN to the WLAN coverage region of the WLAN, the
mobile device causes a message for forwarding voice calls to the
WLAN identification number of the mobile device to be transmitted
through the WWAN. The mobile device also causes a message for
cancelling the forwarding of voice calls to the WWAN telephone
number of the mobile device to be transmitted through the WLAN.
Other additional and alternative techniques are described for more
reliable reachability Referring now to the drawings, FIG. 1 is a
schematic block diagram illustrating the basic components of a
mobile terminal or mobile communication device 102 which operates
in a wireless communication system 100. As shown in FIG. 1, mobile
device 102 is adapted to communicate with a wireless communication
network 104 which is a cellular telecommunications network. Also as
shown, mobile device 102 is adapted to communicate with a wireless
local area network (WLAN) 190 such as an 802.11-based wireless
network. For wireless communication with wireless network x.04,
mobile device 102 utilizes radio frequency (RF) transceiver
circuitry 108a and an antenna 110a. For wireless communication with
WLAN 190, mobile device 102 utilizes RF transceiver circuitry 108b
for 802.11-based communications and an antenna 110b. With such
configuration, mobile device 102 may be referred to as a "dual
mode" communication device. Although shown in FIG. 1 as having
separate and independent transceiver components, at least some
portions or components of these otherwise different transceivers
may be shared where possible.
[0015] Mobile device 102 preferably includes a visual display 112,
a keyboard 114, and perhaps one or more auxiliary user interfaces
(UI) 116, each of which is coupled to a controller 106. Controller
106 is also coupled to RF transceiver circuitry 108a and antenna
110a as well as RF transceiver circuitry 108b and antenna 110b.
Typically, controller 106 is embodied as a central processing unit
(CPU) which runs operating system software in a memory component
(not shown). Controller 106 will normally control overall operation
of mobile device 102, whereas signal-processing operations
associated with communication functions are typically executed by
the RF transceiver circuitry. Controller 106 interfaces with device
display 112 to display received information, stored information,
user inputs, and the like. Keyboard 114, which may be a telephone
type keypad or full alphanumeric keyboard, is normally provided for
entering data for storage in mobile device 102, information for
transmission to network 104, a telephone number to place a
telephone call, commands to be executed on mobile device 102, and
possibly other or different user inputs.
[0016] Mobile device 102 sends communication signals to and
receives communication signals over wireless communication links.
For example, mobile device 102 may communicate with wireless
network 104 via antenna 110a. RF transceiver circuitry 108a
performs functions similar to those of a base station controller
120, including for example modulation/demodulation and possibly
encoding/decoding and encryption/decryption. It is also
contemplated that RF transceiver circuitry 108a may perform certain
functions in addition to those performed by base station controller
120. In the embodiment shown in FIG. 1, wireless network 104
technology is configured in accordance with General Packet Radio
Service (CPRS) and a Global Systems for Mobile (GSM) technologies.
However, any suitable type of communication protocols may be
utilized. For example, the network may be based on code division
multiple access (COMA) or other suitable technologies. It will be
apparent to those skilled in art that RF transceiver circuitry 108a
will be adapted to particular wireless network or networks in which
mobile device 102 is intended to operate.
[0017] Mobile device 102 also includes a battery interface 122 for
receiving one or more rechargeable batteries 124. Battery 124
provides electrical power to electrical circuitry in mobile device
102, and battery interface 122 provides for a mechanical and
electrical connection for battery 124. Battery interface 122 is
coupled to a regulator 126 which regulates power to the device.
Mobile device 102 also operates using a memory module 120, such as
a Subscriber Identity Module (SIM) (or e.g. a Universal SIM or
U-SIM, or a Removable User Identity Module or R-UIM), which is
connected to or inserted in mobile device 102 at an interface
118.
[0018] Mobile device 102 may consist of a single unit, such as a
data communication device, a cellular telephone, a
multiple-function communication device with data and voice
communication capabilities, a personal digital assistant (PDA)
enabled for wireless communication, or a computer incorporating an
internal modem. Alternatively, mobile device 102 may be a
multiple-module unit comprising a plurality of separate components,
including but in no way limited to a computer or other device
connected to a wireless modern. In particular, for example, in the
mobile device block diagram of FIG. 1, RF transceiver circuitry
108a and antenna 110a may be implemented as a radio modern unit
that may be inserted into a port on a laptop computer. In this
case, the laptop computer would include display 112, keyboard 114,
one or more auxiliary UIs 116, and controller 106 embodied as the
computer's CPU. It is also contemplated that a computer or other
equipment not normally capable of wireless communication may be
adapted to connect to and effectively assume control of RF
transceiver circuitry 108a and antenna 110a of a single-unit device
such as one of those described above. Such a mobile device 102 may
have a more particular implementation as described later in
relation to mobile station 202 of FIG. 2.
[0019] Using RF transceiver circuitry 108a, mobile device 102
communicates in and through wireless communication network 104. In
the embodiment of FIG. 1, wireless network 104 is configured in
accordance with GSM and GPRS technologies. Wireless network 104
includes a base station controller (BSC) 120 with an associated
tower station, a Mobile Switching Center (MSC) 122, a Home Location
Register (HLR) 132, a Serving GPRS Support Node (SGSN) 126, and
a
[0020] Gateway GPRS Support Node (GGSN) 128. MSC 122 is coupled to
BSC 120 and to a landline network, such as a Public Switched
Telephone Network (PSTN) 124. SGSN 126 is coupled to BSC 120 and to
GGSN 128, which is in turn coupled to a public or private data
network 130 (such as the Internet). HLR 132 is coupled to MSC 122,
SGSN 126, and GGSN 128.
[0021] The tower station coupled to BSC 120 may be a fixed
transceiver station, and the tower station and BSC 120 may together
be referred to as fixed transceiver equipment. The fixed
transceiver equipment provides wireless network coverage for a
particular coverage area commonly referred to as a "cell", The
transceiver equipment transmits communication signals to and
receives communication signals from mobile devices within its cell
via the tower station. The transceiver equipment normally performs
such functions as modulation and possibly encoding and/or
encryption of signals to be transmitted to the mobile device in
accordance with particular, usually predetermined, communication
protocols and parameters, under control of its controller. The
transceiver equipment similarly demodulates and possibly decodes
and decrypts, if necessary, any communication signals received from
mobile device 102 within its cell. Communication protocols and
parameters may vary between different networks. For example, one
network may employ a different modulation scheme and operate at
different frequencies than other networks.
[0022] For all mobile device's 102 registered with a network
operator, permanent data (such as mobile device 102 user's profile)
as well as temporary data (such as mobile device's 102 current
location) are stored in HLR 132. In case of a voice call to mobile
device 102, HLR 132 is queried to determine the current location of
mobile device 102. A Visitor Location Register (VLR) of MSC 122 is
responsible for a group of location areas and stores the data of
those mobile devices that are currently in its area of
responsibility. This includes parts of the permanent mobile device
data that have been transmitted from HLR 132 to the VLR for faster
access. However, the VLR of MSC 122 may also assign and store local
data, such as temporary identifications. Optionally, the VLR of MSC
122 may be enhanced for more efficient co-ordination of GPRS and
non-GPRS services and functionality (e.g. paging for
circuit-switched calls which may be performed more efficiently via
SGSN 126, and combined GPRS and non-GPRS location updates).
[0023] SGSN 126 is at the same hierarchical level as MSC 122 and
keeps track of the individual locations of mobile devices. SGSN 126
also performs security functions and access control. GGSN 128
provides interworking with external packet-switched networks and is
connected with SGSNs (such as SGSN 126) via an IP-based GPRS
backbone network. SGSN 126 performs authentication and cipher
setting procedures based on the same algorithms, keys, and criteria
as in existing GSM. In conventional operation, cell selection may
be performed autonomously by mobile device 102 or by the fixed
transceiver equipment instructing mobile device 102 to select a
particular cell. Mobile device 102 informs wireless network 104
when it reselects another cell or group of cells, known as a
routing area.
[0024] In order to access GPRS services, mobile device 102 first
makes its presence known to wireless network 104 by performing what
is known as a GPRS "attach". This operation establishes a logical
link between mobile device 102 and SGSN 126 and makes mobile device
102 available to receive, for example, pages via SGSN,
notifications of incoming data, or SMS messages over GPRS. In order
to send and receive GPRS data, mobile device 102 assists in
activating the packet data address that it wants to use. This
operation makes mobile device 102 known to GGSN 128; interworking
with external data networks may thereafter commence. User data may
be transferred transparently between mobile device 102 and the
external data networks using, for example, encapsulation and
tunneling. Data packets are equipped with GPRS-specific protocol
information and transferred between mobile device 102 and GGSN
128.
[0025] Although the present embodiment relates to a WLAN of the
802.11 type and a WWAN of the cellular network type, any suitable
wireless network technologies may be utilized, such as WIMAX
technologies (e.g. 802.16e-based technologes). For example, the
WLAN may be an 802.11-based network and the WWAN may be an
802.16e-based network. As another example, the WLAN may be an
802.16e-based network and the WWAN may be the cellular network.
[0026] To illustrate the basic WLAN environment and architecture,
FIG. 2 is a block diagram which shows a communication system 200
which includes a public network 130 (e.g. the Internet 130) and a
private network 204. In the present embodiment, private network 204
is or includes the WLAN 190 of FIG. 1. In the WLAN, terminals (e.g.
mobile terminal or device 102 of FIG. 1) may connect to their
associated networks through access points (APs) as shown.
Preferably, at least some of the APs are wireless APs of the WLAN
and at least some of the terminals are mobile/wireless
communication devices which interface and connect through these
wireless APs. Such terminals and APs may operate in accordance with
well-known IEEE 802.11 standards, for example. The terminals shown
in public network 130 include terminals 210 and 212 which have
interfaced with AP 206, and terminals 214, 216, and 218 which have
interfaced with AP 208. The terminals shown in private network 204
include terminals 102, 236, 238 which have interfaced with AP 232,
and terminals 244 and 246 which have interfaced with AP 242.
Outside of the networks 130 and 204 of FIG. 2 is a wireless wide
area network (WWAN) (not shown in FIG. 2) which may be a cellular
telecommunication network having a plurality of base stations and
additional components (e.g. see FIG. 1). At least some of the
terminals of FIG. 2 are adapted to operate in both WLANs and
WWANs.
[0027] Private network 204 which includes the WLAN provides various
data and communication services to its terminals. For example,
private network 204 may provide for voice telephony communication
services for its terminals with use of Voice over IP (VoIP)
communications. For these types of VoIP services, private network
204 may utilize servers such as a Session Initiation Protocol (SIP)
proxy server 228 to help facilitate VoIP communications. In the
present embodiment, communication system 200 has a SIP proxy server
121 in a public WLAN 192 as well. Note that some communication
applications utilized by terminals, such VoIP applications, require
the use of SIP. SIP is well-documented in standard documents such
as Request For Comments (RFC) 3261. When terminals enter into the
WLAN, they are typically assigned a unique IP address through an
address assigning mechanism 220 such as a dynamic host
configuration protocol (DHCP) server. Note also that a firewall 124
may be provided in private network 104 for preventing unauthorized
access from unauthorized users in public network 102.
[0028] As apparent, mobile terminals may operate to place and
receive voice calls within WLANs with the assistance of SIP
components such as SIP proxy servers 121 and 228. SIP proxy servers
may include one or more SIP functional components such as proxy
server functionality, registrar server functionality, redirect
server functionality, and location server functionality. In the
present embodiment, a separate location server 230 is used in
private network 204 and is updated regularly to include the last
known addresses of the mobile terminals, Voice calls to a mobile
terminal in a WLAN is typically made with use of a SIP identity or
SIP address. A SIP address is an e-mail address in the format of
sip:userID@gateway,com. The user ID may be a user name or an E.164
address. Mobile terminals typically register with a registrar
server using their assigned SIP addresses, and the registrar server
provides this information to location server 230 upon request.
[0029] When a caller calls a mobile terminal, an INVITE request is
sent to the proxy server which identifies the proper path and
forwards the request to the mobile terminal. A gateway 295 (i.e. a
VoIP-to-PSTN, PSTN-to-VoIP gateway) is connected in private network
204 and is operative to communicate with PSTN 124 so that voice
calls may be made through ordinary telephone lines (and e.g.
cellphones in wireless network 104) as well as through IP networks.
Thus, in the case of an incoming call through PSTN 124, gateway 295
is operative to issue this
[0030] INVITE request in response to detecting the incoming call.
The mobile terminal responds to the proxy server which, in turn,
forwards the response to the caller (via gateway 295 if the call is
through PSTN 124). A VoIP session for VoIP communications may then
proceed between the caller and the mobile terminal. When a redirect
server is used, the caller sends an INVITE request to the redirect
serer which contacts location server 230 to determine the path of
the mobile terminal. The redirect server sends the location
information back to the caller, which sends a request to the mobile
terminal at the address indicated in the redirection
information.
[0031] Referring now to FIG. 3, electrical components of a
preferred mobile terminal 102 (e.g, a mobile communication device
or mobile station) will be described. Terminal 102 is adapted to
operate in connection with the communications systems 100/200 of
FIGS. 1 and 2 (WLAN and WWAN). Terminal 102 is preferably a two-way
mobile communication device having at least voice and advanced data
communication capabilities, including the capability to communicate
with other computer systems. Depending on the functionality
provided by terminal 102, it may be referred to as a data messaging
device, a two-way pager, a cellular telephone with data messaging
capabilities, a wireless Internet appliance, or a data
communication device (with or without telephony capabilities).
[0032] As described, terminal 102 is adapted to wirelessly
communicate with WLAN 190. Also as shown, terminal 102 may be
adapted to wirelessly communicate with cellular base station
transceiver systems 300. For communication with cellular networks,
terminal 102 utilizes communication subsystem 311. For
communication with WLANs, terminal 102 utilizes an additional
communication subsystem 391 which has the same or similar
structural components as communication subsystem 311. With such
configuration, terminal 102 may be referred to as a "dual mode"
mobile station. Although shown in FIG. 3 as having separate and
independent subsystems, at least some portions or components of
these otherwise different subsystems may be shared where
possible.
[0033] Communication subsystem 311 includes a receiver 312, a
transmitter 314, and associated components, such as one or more
(preferably embedded or internal) antenna elements 316 and 318,
local oscillators (LOs) 313, and a processing module such as a
digital signal processor (DSP) 320. Communication subsystem 311 is
analogous to RF transceiver circuitry 108a and antenna 110a shown
in FIG. 1. As will be apparent to those skilled in field of
communications, particular design of communication subsystem 311
depends on the communication network in which terminal 102 is
intended to operate.
[0034] Terminal 102 may send and receive communication signals
through the network after required network procedures have been
completed. Signals received by antenna 316 through the network are
input to receiver 312, which may perform such common receiver
functions as signal amplification, frequency down conversion,
filtering, channel selection, and like, and in example shown in
FIG. 3, analog-to-digital (A/D) conversion. A/D conversion of a
received signal allows more complex communication functions such as
demodulation and decoding to be performed in DSP 320. In a similar
manner, signals to be transmitted are processed, including
modulation and encoding, for example, by DSP 320. These
DSP-processed signals are input to transmitter 314 for
digital-to-analog (D/A) conversion, frequency up conversion,
filtering, amplification and transmission over communication
network via antenna 318. DSP 320 not only processes communication
signals, but also provides for receiver and transmitter control.
For example, the gains applied to communication signals in receiver
312 and transmitter 314 may be adaptively controlled through
automatic gain control algorithms implemented in DSP 320.
[0035] Network access is associated with a subscriber or user of
terminal 102, and therefore terminal 102 requires a memory module
362, such as a Subscriber Identity Module or "SIM" card, a
Universal SIM (U-SIM), or a Removable User Identity Module (R-UIM),
to be inserted in or connected to an interface 364 of terminal 102
in order to operate in the network. Since terminal 102 is a mobile
battery-powered device, it also includes a battery interface 354
for receiving one or more rechargeable batteries 356. Such a
battery 356 provides electrical power to most if not all electrical
circuitry in terminal 102, and battery interface 354 provides for a
mechanical and electrical connection for it. Battery interface 354
is coupled to a regulator (not shown in FIG. 3) that provides power
V+ to all of the circuitry.
[0036] Terminal 102 includes a microprocessor 338 that controls
overall operation of terminal 102. This control includes the call
forwarding processing techniques of the present application.
Communication functions, including at least data and voice
communications, are performed through communication subsystem 311.
Microprocessor 338 also interacts with additional device subsystems
such as a display 322, a flash memory 324, a random access memory
(RAM) 326, auxiliary input/output (I/O) subsystems 328, a serial
port 330, a keyboard 332, a speaker 334, a microphone 336, a
short-range communications subsystem 340, and any other device
subsystems generally designated at 342. Some of the subsystems
shown in FIG. 3 perform communication-related functions, whereas
other subsystems may provide "resident" or on-device functions.
Notably, some subsystems, such as keyboard 332 and display 322, for
example, may be used for both communication-related functions, such
as entering a text message for transmission over a communication
network, and device-resident functions such as a calculator or task
list. Operating system software used by microprocessor 338 is
preferably stored in a persistent store such as flash memory 324,
which may alternatively be a read-only memory (ROM) or similar
storage element (not shown). Those skilled in the art will
appreciate that the operating system, specific device applications,
or parts thereof, may be temporarily loaded into a volatile store
such as RAM 326.
[0037] Microprocessor 338, in addition to its operating system
functions, preferably enables execution of software applications on
terminal 102. A predetermined set of applications that control
basic device operations, including at least data and voice
communication to applications, will normally be installed on
terminal 102 during its manufacture. A preferred application that
may be loaded onto terminal 102 may be a personal information
manager (PIM) application having the ability to organize and manage
data items relating to user such as, but not limited to, e-mail,
calendar events, voice mails, appointments, and task items.
Naturally, one or more memory stores are available on terminal 102
and SIM 356 to facilitate storage of PIM data items and other
information.
[0038] The PIM application preferably has the ability to send and
receive data items via the wireless network. In a preferred
embodiment, PIM data items are seamlessly integrated, synchronized,
and updated via the wireless network, with the wireless device
user's corresponding data items stored and/or associated with a
host computer system thereby creating a mirrored host computer on
terminal 102 with respect to such items. This is especially
advantageous where the host computer system is the wireless device
user's office computer system. Additional applications may also be
loaded onto terminal 102 through network, an auxiliary I/O
subsystem 328, serial port 330, short-range communications
subsystem 340, or any other suitable subsystem 342, and installed
by a user in RAM 326 or preferably a non-volatile store (not shown)
for execution by microprocessor 338. Such flexibility in
application installation increases the functionality of terminal
102 and may provide enhanced on-device functions,
communication-related functions, or both. For example, secure
communication applications may enable electronic commerce functions
and other such financial transactions to be performed using
terminal 102.
[0039] In a data communication mode, a received signal such as a
text message, an e-mail message, or web page download will be
processed by communication subsystem 311 and input to
microprocessor 338. Microprocessor 338 will preferably further
process the signal for output to display 322 or alternatively to
auxiliary I/O device 328. A user of terminal 102 may also compose
data items, such as e-mail messages, for example, using keyboard
332 in conjunction with display 322 and possibly auxiliary I/O
device 328. Keyboard 332 is preferably a complete alphanumeric
keyboard and/or telephone-type keypad. These composed items may be
transmitted over a communication network through communication
subsystem 311. For voice communications, the overall operation of
terminal 102 is substantially similar, except that the received
signals would be output to speaker 334 and signals for transmission
would be generated by microphone 336. Alternative voice or audio
I/O subsystems, such as a voice message recording subsystem, may
also be implemented on terminal 102. Although voice or audio signal
output is preferably accomplished primarily through speaker 334,
display 322 may also be used to provide an indication of the
identity of a calling party, duration of a voice call, or other
voice call related information, as some examples.
[0040] Serial port 330 in FIG. 3 is normally implemented in a
personal digital assistant (PDA)-type communication device for
which synchronization with a user's desktop computer is a
desirable, albeit optional, component. Serial port 330 enables a
user to set preferences through an external device or software
application and extends the capabilities of terminal 102 by
providing for information or software downloads to terminal 102
other than through a wireless communication network. The alternate
download path may, for example, be used to load an encryption key
onto terminal 102 through a direct and thus reliable and trusted
connection to thereby provide secure device communication.
Short-range communications subsystem 340 of FIG. 3 is an additional
optional component that provides for communication between terminal
102 and different systems or devices, which need not necessarily be
similar devices. For example, subsystem 340 may include an infrared
device and associated circuits and components, or a Bluetooth.TM.
communication module to provide for communication with similarly
enabled systems and devices. Bluetooth.TM. is a registered
trademark of Bluetooth SIG, Inc.
[0041] According to the present application, a mobile terminal
utilizes call forwarding techniques to be reliably reachable when
operating in either a WLAN or WWAN. When switching communication
operations from a WLAN coverage region of the WLAN to a WWAN
coverage region of the WWAN, the mobile terminal causes a message
for forwarding voice calls to a WWAN identification number of the
mobile terminal to be transmitted through the WLAN. The mobile
terminal also causes a message for cancelling the forwarding of
voice calls to a WLAN identification number of the mobile terminal
to be transmitted through the WWAN. When switching communication
operations from the WWAN coverage region of the WWAN to the WLAN
coverage region of the WLAN, the mobile terminal causes a message
for forwarding voice calls to the WLAN identification number of the
mobile device to be transmitted through the WWAN. The mobile
terminal also causes a message for cancelling the forwarding of
voice calls to the WWAN telephone number of the mobile terminal to
be transmitted through the WLAN. Other additional and alternative
techniques are described for reliable reachability.
[0042] FIGS. 4-7 are top down views of an environment within which
mobile terminal 102 has been carried along a travel path 410
through wireless communication systems 100/200 which include a WWAN
450 (e.g. a GSM/GPRS network) and one or more wireless local area
networks (WLANs) 190 and 404. Although only cell coverage regions
are shown in the top down views for simplicity, each network 190,
404, and 450 includes those network components and functionality as
described in relation to FIGS. 1-2. When comparing the two types of
networks, WWAN 450 and WLANs 190/404 may be referred to as
heterogeneous wireless communication networks.
[0043] In the embodiment described, mobile terminal 102 operates
for communications with only one of the networks (WLAN or WWAN) at
any given time, and may give preference to operate with WLANs over
WWANs when a WLAN is available for communications. Note that
oftentimes, if not always, mobile terminal 102 operates within the
coverage region of WWAN 450 although it may not set its transceiver
for communications with WWAN 450.
[0044] In FIG. 4, mobile terminal 102 is shown within the coverage
region of ALAN 190 for communications through WLAN 190; in FIGS.
5-6, mobile terminal 102 is shown to have moved along travel path
410 outside of the coverage region of WLAN 190 and within the
coverage region of WWAN 450 for communications through WWAN 450 in
a WWAN coverage region 450; in FIG. 7, mobile terminal 102 is shown
to have moved within the coverage region of WLAN 404 for
communications through WLAN 404. A close-up top down view is
provided in FIG. 5, where it is shown that WLAN 190 has a plurality
of wireless access points (APs) including AP 222 and 232 associated
with WLAN coverage regions 512 and 508, respectively, which define
an RF coverage border between WLAN 190 and the WWAN.
[0045] As described earlier, mobile terminal 102 has two different
RF transceiver portions (e.g. transceiver portions 110a and 110b of
FIG. 1) associated with the two different types of networks (WLAN
and WWAN) and operates for communications with only one of the
networks (WLAN or WWAN) at any given time. Each RF transceiver
portion of mobile terminal 102 is associated with a unique
identification number (e.g. telephone number, IP address, SIP
address, etc.) so that mobile terminal 102 may receive voice calls
through both WLAN and WWAN: a WLAN identification number for WLANs
190 and 404 and a WWAN identification number for WWAN 450.
[0046] Normally, when mobile terminal 102 operates in WLAN 190 and
404 (e.g. FIG. 4 or FIG. 7), it is reachable by its WLAN
identification number in WLAN 190 and 404 but otherwise may be
out-of-service with WWAN 450 and not be reachable with use of the
WWAN identification number. Alternatively, from a cost standpoint
it may be preferred to reach mobile terminal 102 via WLAN 190 and
404 instead of WWAN 450 even when the call is placed using the WWAN
identification number. On the other hand, when mobile terminal 102
operates in WWAN 450 (e.g. FIG. 6), it is reachable by its WWAN
identification number in WWAN 450 but otherwise may be
out-of-service with WLAN 190/404 and not be reachable with use of
the WLAN identification number. Using techniques of the present
application, however, these concerns are alleviated.
[0047] FIG. 8 is a flowchart which helps describe call forwarding
methods of the mobile terminal according to the present
application. The steps of the flowchart are taken from the
perspective of the mobile terminal having a dual- or multi-mode
capability. The steps of the flowchart are performed by one or more
controllers or processors of the mobile terminal (e.g. see FIGS. 1
and 3), and may be embodied as a computer program product which
includes a computer readable medium and computer instructions
stored in the computer readable medium which are executable by the
controllers/processors for performing the method.
[0048] It is initially assumed that steady-state communication
operations are between the mobile terminal and a WLAN (step 802 of
FIG. 8). If the mobile terminal identifies that a vertical handoff
from the WLAN to the WWAN is imminent (step 804 of FIG. 8), then
operation proceeds to step 806; otherwise the mobile terminal
continues to operate in the WLAN at step 806. When the vertical
handoff is identified to be imminent at step 804 (e.g. see
transition in FIGS. 5-7), then the mobile terminal sends to the
WLAN a message for forwarding all voice calls directed to the WLAN
identification number to the WWAN (step 806 of FIG. 8). Preferably,
this message includes the call forwarding number, that is, the WWAN
identification number where the mobile terminal will be reachable
in the WWAN. The WWAN identification number of the call forwarding
message is received and stored at a location server (e.g. location
server 130 of FIG. 2) so that any call destined to the mobile
terminal in the WLAN will be redirected to the mobile terminal in
the WWAN. Next, the mobile terminal causes communication operations
to be switched from the WLAN to the WWAN (step 808 of FIG. 8). For
example, see the position of mobile terminal 102 in FIG. 6. The
WLAN transceiver portion of the mobile terminal is placed into a
power down mode of operation, as it is no longer in use. After
switching communication operations to the to WWAN, the mobile
terminal sends to the WWAN a message for cancelling the previous
call forwarding of all voice calls directed to the WWAN
identification number to the WLAN (step 810 of FIG. 8). This
message need not include any call forwarding number, but merely a
command to cancel the call forwarding. Thus, the mobile terminal is
reachable in the WWAN by use of the WWAN identification number as
well as the WLAN identification number since the WWAN forwarding
number was previously received and stored at the location server
(e.g. location server 130 of FIG. 2).
[0049] Steady-state communication operations then proceed between
the mobile terminal and the WWAN (step 812 of FIG. 8). If the
mobile terminal identifies that a vertical handoff from the WWAN to
the WLAN is imminent (step 814 of FIG. 8), then operation proceeds
to step 816; otherwise the mobile terminal continues to operate in
the WWAN at step 812. When the vertical handoff is identified to be
imminent at step 814 (e.g. see transition in. FIGS. 6-7), then the
mobile terminal sends to the WWAN a message for forwarding all
voice calls directed to the WWAN identification number to the WLAN
(step 816 of FIG. 8). Preferably, this message includes the call
forwarding number, that is, the WLAN identification number where
the mobile terminal will be reachable in the WLAN. The WLAN
identification number of the call forwarding message is received
and stored at a HLR of the WWAN (e.g. HLR 132 of FIG. 1) or other
database so that any call destined to the mobile terminal in the
WWAN will be redirected to the mobile terminal in the WLAN. Next,
the mobile terminal causes communication operations to be switched
from the WWAN to the WLAN (step 818 of FIG, 8). For example, see
the position of mobile terminal 102 in FIG. 6. The WWAN transceiver
portion of the mobile terminal is then placed into a power down
mode of operation, as it is no longer in use. After switching
communication operations to the WLAN, the mobile terminal sends to
the WLAN a message for cancelling the previous call forwarding of
all voice calls directed to the WLAN identification number to the
WWAN (step 820 of FIG. 8). This message need not include any call
forwarding number, but merely a command to cancel the call
forwarding. Thus, the mobile terminal is reachable in the WLAN by
use of the WLAN identification number as well as the WWAN
identification number since the WLAN forwarding number was
previously received and stored at the HLR (e.g. HLR 132 of FIG. 1).
Steady-state communication operations then proceed between the
mobile terminal and the WLAN in step 802, and operation repeats as
described previously. The flowchart description for FIG. 8 is
completed.
[0050] Referring back to FIG. 5, note that a wireless AP 614 may be
provided in WLAN 190 to serve as an AP tripwire in an RF coverage
region 502 (i.e. an ingress/egress region between dashed lines 550
and 552) of WLAN 190. This may provide an adequate triggering
mechanism for mobile terminal 102 to send the call forwarding
message and switch communication operations to the WWAN, when
switching as described in relation to step 806-810 and/or steps
816-820 of FIG. 8. However, there is still a concern that, during
the transition through travel path 410 shown in FIG. 5, mobile
terminal 102 may fail to adequately send the forwarding message to
forward calls directed to the WLAN identification number to the
WWAN. This may happen, for example, due to an abrupt RF coverage
"cut-off" inherent in WLANs; this problem is not inherent in WWANs
as they are assumed to provide relatively continuous coverage for
all practical purposes. Due to this problem, mobile terminal 102 is
further configured to operate to send the forwarding message of
step 806 of FIG. 8 through the WWAN after communication operations
are switched to and established with the WWAN in step 808. In this
case, mobile terminal 102 utilizes its data communication
capability in the WWAN (e.g. see earlier description in relation to
FIGS. 1 and 3) to send a forwarding or location message with the
WWAN identification number through Internet 130 to location server
230.
[0051] This particular technique may be an alternative step to step
806 of FIG. 8, or an additional "backup" step to step 806 of FIG,
8. If it is an alternative step to step 806 of FIG. 8, then the
mobile terminal may be operative to always use its WWAN transceiver
portion to communicate call forwarding information and cancel call
forwarding information to the appropriate network components (WWAN,
and even WLAN in steps 806 and/or 820). If it is an additional
backup step to step 806 of FIG. 8, then the step may be performed
by mobile terminal 102 in response to detecting any suitable
condition where it is required to ensure or confirm an adequate
call forwarding state. For example, the mobile terminal may have
detected an abrupt WLAN coverage Foss where only WWAN coverage is
available. As another example, the mobile terminal may have
detected a power-down by the end user or reset, followed by a
power-on where WWAN coverage is available and WLAN coverage is
not.
[0052] Thus, methods and apparatus for use by a mobile
communication device in facilitating voice calls through a wireless
local area network (WLAN) and a wireless wide area network (WWAN)
have been described. When switching communication operations from a
WLAN coverage region of the WLAN to a WWAN coverage region of the
WWAN, the mobile device causes a message for forwarding voice calls
to a WWAN identification number of the mobile device to be
transmitted through the WLAN. The mobile device subsequently causes
a message for cancelling the forwarding of voice calls to a WLAN
identification number of the mobile device to be transmitted
through the WWAN. When switching communication operations from the
WWAN coverage region of the WWAN to the WLAN coverage region of the
WLAN, the mobile device causes a message for forwarding voice calls
to the WLAN identification number of the mobile device to be
transmitted through the WWAN, The mobile device subsequently causes
a message for cancelling the forwarding of voice calls to the WWAN
telephone number of the mobile device to be transmitted through the
WLAN. Other additional and alternative techniques are described for
reliable reachability.
[0053] The above-described embodiments of the present application
are intended to be examples only. Although the embodiment described
related to a WLAN of the 802.11 type and a WWAN of the cellular
network type, any suitable wireless network technologies may be
utilized, such as WiMAX technologies (e.g. 802.16e-based
technologes). For example, the WLAN may be an 802.11-based network
and the WWAN may be an 802.16e-based network. As another example,
the WLAN may be an 802.16e-based network and the WWAN may be the
cellular network. Those of skill in the art may effect alterations,
modifications and variations to the embodiments without departing
from the scope of the application.
[0054] What is claimed is:
* * * * *