INTEGRATED CELLULAR AND WIRELINE TELEPHONE SERVICE
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates to communication systems.
More particularly, the invention relates to systems and methods for
integrated portable cellular and wired line telephone service.
Background Discussion
Mobile cellular and personal communication system (PCS) devices
allow users to place or receive telephone calls at any point throughout
a wireless telephone network. A cellular/PCS device is convenient when
the user is mobile, since it accesses a telephone network using a wireless
link. However, a call made or received on a cellular/PCS device is much
more expensive than a call on a wired line network due, in part at least,
to the high costs required for installing, operating and maintaining an air
link for the cellular/PCS device. To lower the costs of cellular/PCS
service, one industry proposal is to have a subscriber personal base
station, for example, a cordless phone receiver, originate a call to a
cellular/PCS network, notifying the network to route all cellular calls to
a subscriber's wired line phone number when the subscriber's
cellular/PCS device is within range of or docked in the base station. The
originated call from the base station goes to a new network element at
a mobile switching center that answers the call, collects the necessary
information, emulates a visitors location register (VLR) and originates
a registration notification to a subscribers home location register (HLR).
When registered, the call will result in the HLR querying the new
network element or special VLR for re-routing information on all
subsequent calls made to the subscriber's cellular number. The special
VLR will respond to the HLR by re-routing such subsequent calls to the
subscribers wired line phone number. However, such special VLRs
result in higher network costs for equipment and maintenance and
further result in more signalling overhead for cellular/PCS networks.
Accordingly, there is a need to further improve integrated cellular and
wired lined telephone service to eliminate special equipment and
accompanying additional signalling thereby enabling subscribers to effect
savings in the costs of air time for calls made to a subscriber's
cellular/PCS device number while the subscriber is at home.
SUMMARY OF THE INVENTION
The present invention satisfies the need previously described in a
cellular/PCS network. The invention includes a Mobile Switching Center
(MSC) coupled to a public switched telephone network (PSTN). Each
cellular/PCS device in the network cooperates with a personal base
station at the subscriber location. The personal base station has the
facility to detect the presence of the cellular/PCS device within a selected
range. When a cellular/PCS device is within the selected range of or
docked in the personal base station a message is sent by the base station
over an airlink to the MSC and on to the HLR. The message causes the
MSC under the direction of the HLR to forward the subscriber's
incoming cellular call to his plain old telephone service (POTS)/wired
line service instead of to his cellular device thereby saving airtime. A
home location register (HLR) in the PSTN serving the mobile switching
center for the cellular/PCS device is modified to have a new type of call
forwarding protocol. The new call forwarding protocol is activated only
when the subscriber5 cellular/PCS device is within range of or docked in
the personal base station. In this case, all calls to the cellular/PCS device
are routed to the subscriber's wired lined phone number. Several
alternate methods are provided for notifying the HLR of the need to
activate the new "subscriber home" call forwarding method. A first
method involves the personal base station originating a signalling
message to the HLR indicating that the subscriber's cellular/PCS device
is at the home location. A second method involves the subscriber's
cellular/PCS device originating a signalling message to the HLR
indicating that it is within range of the personal base station and thus
home.
In the foregoing methods, the "subscriber home" call forwarding
for his wired line phone would be deactivated upon a receipt of a
registration notification from the subscriber's cellular/PCS device.
BRIEF DESCRIPTION OF THE DRAWING
The invention will be better understood from the following
description of preferred embodiments taken in conjunction with the
accompanying drawing, in which:
Figure 1 is a block diagram of an integrated cellular and wired line
telephone system incorporating the principles of the present invention.
Figure 2 is a flow diagram of a cellular registration in the cellular
network of Figure 1.
Figure 3 is a flow diagram of a personal base station registration
in the cellular network of Figure 1.
Figure 4 is a flow diagram of a cellular call termination in the
cellular network of Figure 1.
Figure 5 is a flow diagram of a personal base station call
termination in the cellular network of Figure 1.
Figure 6 is a flow diagram of a personal base station de-
registration in the cellular network of Figure 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In Figure 1, a conventional cellular/PCS device 10 which is part of
a mobile cellular network including a plurality of devices 10 (not shown)
is coupled to a mobile switching center (MSC) 12. The mobile device
10 is operated by a subscriber having a home location or office which
includes a personal base station 14 coupled over an airlink to the MSC
and a standard wiredline telephone 16 coupled through a wire line 20
and an end office 22 to a public switched telephone network (PSTN) 18.
The end office is a typical end office providing user with wiredline plain
old telephone service (POTS) to the telephone 16. Also coupled to the
network 18 is any calling phone 24 which may be wireless or wired line,
able to originate a phone call to a cellular/PCS subscriber.
The personal base station 14 detects the presence of the
cellular/PCS device 10 when within a selected range or docked in the
base station 14. The base station 14 includes a conventional proximity
device and an interface to communicate over an airlink to the MSC to
which the cellular/PCS device is assigned. Any message originated by the
base station includes a source address of the base station and a
destination address of a home location register (HLR) 26. The base
station triggers a message to initiate call forwarding of the subscribers
incoming mobile calls to his POTS wired line service when the subscriber
cellular/PCS device is within range of or docked in the base station. T e
base station also includes a message to the HLR assigned to the
cellular/PCS device to turn off call forwarding of cellular calls when the
device is not within the range of or docked in the base station. Also
included in the base station is a light or signal (not shown) to indicate
that call forwarding is or is not re-directing calls from the cellular/PCS
device to the POTS phone. The base station may also include an on/off
switch (not shown) to override the proximity detection device.
The MSC 12 includes a visitor location register (VLR). Both the
MSC and the VLR are typical components used in a cellular/PCS mobile
network. To this effect, the VLR includes a program stored in a memory
(not shown) to recognize messages sent by each base station indicating
whether call forwarding should be activated or deactivated for the
cellular/PCS device assigned to such base station. In response to such
message, the VLR identifies the address or phone number for directing
calls to the cellular/PCS device or to the POTS phone, as the case may
be.
*,».ΛaΛ 97/24004
A home location register (HLR) 26 coupled to the MSC VLR
manages the correlation between the phone 10 and the base station 14
in initiating or terminating the transfer of a mobile call between the
phone 10 and the phone 16. The HLR records in a data base (not
shown) the address or phone number to which calls should be directed
to for a subscriber's cellular/PCS device or his POTS phone, according
to the message received from the VLR.
Turning to Figure 2, a typical cellular phone registration with the
MSC is shown. This call flow would be used for all registration by the
subscriber's cellular/PCS device. In an operation 201, a subscriber
initiates the ceilular/PCS device registration with the HLR. The
procedure can be initiated when the subscriber powers on the phone;
originates a call; changes the MSC/VLR serving location as well as other
actions. In an operation 203, the cellular/PCS device sends a message
to the MSC/VLR serving the phone. In an operation 205, the
MSC/VLR sends a message to the HLR indicating the location of the
cellular/PCS device and the call forwarding number serving the phone.
The phone number for the cellular/PCS device is the default condition.
In an operation 207, the HLR records the location and the call
forwarding number of the cellular/PCS device in the HLR database.
Turning to Figure 3, the personal base station registration process
is shown. This registration procedure results from the subscriber's phone
being within range of or docked in the base station 14. In an operation
301, the base station 14 detects the cellular/PCS devices's radio signal or
the presence of the device docked in the personal base station.
In an operation 303, the personal base station initiates the
registration procedure after the detection of the presence of the
cellular/PCS device. In response to such actions, the base station out
pulses a message to the VLR containing a source address for the base
station; a destination address for the HLR assigned to the base station
and an identification number for call forwarding subscriber cellular call
to a POTS phone.
In an operation 305, the MSC/VLR notifies the HLR of the
cellular/PCS registration and the call forwarding number. In operation
307, the HLR recognizes the change in registration and transfers any call
to the cellular/PCS device to the subscriber's wired line phone.
In Figure 4, a typical cellular call termination procedure is shown
for a cellular/PCS call. This call flow would be used when the subscriber
is not within the range of the personal base station.
In an operation 401, a call is originated from any phone to the
subscriber's cellular/PCS device number.
In an operation 403, the call traverses the necessary telephone
networks to the MSC/VLR associated with the subscriber's home MSC.
In an operation 405, the MSC/VLR queries the HLR for the
location and treatment for handling the call. In this instance the
subscriber is being served by the same MSC that is the subscriber's home
MSC.
In an operation 407, the HLR indicates to the MSC that the call
is to be completed to the cellular/PCS device since the device is not
within the range of or docked in the base station.
In an operation 409, the MSC completes the call to the
cellular/PCS device.
In Figure 5, a basestation call termination process is shown when
the subscriber is within range of or docked in the personal base station.
In this case, the resulting call is forwarded to the subscriber's wired line
service and not to the cellular/PCS device. In an operation 501, a call
is originated from any phone to the subscribers cellular/PCS device
number.
In an operation 503, the call traverses the necessary telephone
network to the MSC/VLR associated with the subscriber's home MSC
and initiates call processing.
In an operation 505, the MSC/VLR queries the HLR for call
handling information. In this instance, the HLR will have detected the
registration of the personal base station, as described in Figure 3. As a
result, the HLR will determine that the call is to be forwarded to the
subscriber's wired line service.
In an operation 507, the HLR indicates to the MSC that the call
is to be forwarded to the subscriber's local POTS phone.
In an operation 509, the MSC forwards the call to the end office
providing the subscriber local service. It should be noted that there will
not necessarily be direct trunking between the MSC and the end office.
In an operation 511, the end office completes the call to the
subscriber's POTS phone.
In Figure 6, the call flow is shown for basestation deregistration
after a selected time interval when the subscriber's cellular/PCS device
is no longer in range of the personal base station. In this case, cellular
calls are directed to the subscriber's cellular/PCS device.
In an operation 601, the base station detects that the cellular/PCS
device is no longer within its range either by the loss of the radio signal
or the removal of the cellular/PCS device from the docking station.
In an operation 603, the base station after a selected time interval
initiates de-registration from the network, i.e., a simulated power down.
A message is sent by the base station through the MSC/VLR indicating
the de-registration condition of the base station.
In an operation 605, the MSC VLR forwards the de-registration
to the HLR.
In an operation 607, the HLR updates the subscriber profile and
restore incoming calls to the cellular PCS device.
In summary, an integrated cellular and wired lined telephone
system has been described in which cellular calls are forwarded to a
wired lined phone at a subscriber location when a cellular/PCS device
assigned to such subscriber location, is within the range of, or docked in
a base station located at such subscriber location. When the cellular/PCS
device is not within the range of or docked in the base station, a second
message from the base station to the MSC causes the call forwarding
address stored in the HLR to forward calls to the cellular/PCS device.
The system lowers the use and cost of air time by a cellular/PCS device
which makes such service more attractive to the general public. Further,
the improvement is achieved with few modifications to a conventional
mobile cellular telephone system.
While the present invention has been described with respect to
specific embodiments, the description is illustrative of the invention and
is not to be construed as limiting the invention. Various modifications
may occur to those skilled in the art without departing from the spirit and the scope of the invention.