U.S. patent application number 14/715668 was filed with the patent office on 2016-11-24 for methods for improved single radio long term evolution (srlte) mobile termination (mt) call success rate for mobile switching center (msc)-sub paging scenarios.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Bhaskara Viswanadham Batchu, Prabhanjan Reddy Pingili, Chintan Shirish Shah, Sharad Shahi.
Application Number | 20160345291 14/715668 |
Document ID | / |
Family ID | 56087512 |
Filed Date | 2016-11-24 |
United States Patent
Application |
20160345291 |
Kind Code |
A1 |
Batchu; Bhaskara Viswanadham ;
et al. |
November 24, 2016 |
METHODS FOR IMPROVED SINGLE RADIO LONG TERM EVOLUTION (SRLTE)
MOBILE TERMINATION (MT) CALL SUCCESS RATE FOR MOBILE SWITCHING
CENTER (MSC)-SUB PAGING SCENARIOS
Abstract
Various embodiments provide methods, devices, and non-transitory
processor-readable storage media for mitigating the risk of delayed
connection or call failure during base station handover by
preventing single radio long term evolution (SRLTE) communication
devices from dropping Mobile Termination (MT) paging messages due
to paging channel mismatches (e.g., mismatches between the Walsh
codes used for different paging channels).
Inventors: |
Batchu; Bhaskara Viswanadham;
(Hyderabad, IN) ; Pingili; Prabhanjan Reddy;
(Hyderabad, IN) ; Shah; Chintan Shirish; (San
Diego, CA) ; Shahi; Sharad; (Boulder, CO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
56087512 |
Appl. No.: |
14/715668 |
Filed: |
May 19, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 68/005 20130101;
H04W 36/08 20130101; H04J 13/0048 20130101; H04W 68/02 20130101;
H04W 88/06 20130101 |
International
Class: |
H04W 68/02 20060101
H04W068/02; H04J 13/00 20060101 H04J013/00 |
Claims
1. A method for managing Mobile Termination (MT) paging messages in
a single radio long term evolution (SRLTE) communication device,
comprising: receiving an MT paging message; determining whether a
base station handover has occurred since the MT paging message was
received; determining a current paging channel that the SRLTE
communication device selected from a current serving base station
in response to determining that the base station handover has
occurred since the MT paging message was received; determining
whether there is a mismatch between the current paging channel and
an original paging channel that the SRLTE communication device had
selected from an original serving base station when the MT paging
message was received; and sending a MT page response message to the
current serving base station on the current paging channel in
response to determining the mismatch between the current paging
channel and the original paging channel.
2. The method of claim 1, wherein determining whether there is a
mismatch between the current paging channel and an original paging
channel that the SRLTE communication device had selected from an
original serving base station when the MT paging message was
received comprises: determining whether a first Walsh code of the
current paging channel and a second Walsh code of the original
paging channel are the same when the current paging channel and the
original paging channel have a common carrier frequency.
3. The method of claim 1, further comprising sending the MT page
response message to the original serving base station on the
original paging channel in response to determining that the base
station handover has not occurred since the MT paging message was
received.
4. The method of claim 1, further comprising sending the MT page
response message to the current serving base station on the
original paging channel in response to determining that there is
not a mismatch between the current paging channel and the original
paging channel.
5. The method of claim 1, further comprising: reconfiguring a
single radio frequency (RF) resource to respond to the MT paging
message; and determining the current serving base station after
reconfiguring the single RF resource.
6. The method of claim 1, further comprising determining the
original paging channel that the SRLTE communication device had
selected from the original serving base station when the MT paging
message was received.
7. The method of claim 1, further comprising: determining whether a
Max Access Probe Exit (MAPE) threshold is exceeded after sending
the MT page response message on the current paging channel; and
stopping sending of the MT page response message on the current
paging channel without adding the current serving base station or
the current paging channel to a temporary avoidance/forbidden list
in response to determining that the MAPE threshold is exceeded.
8. The method of claim 7, wherein stopping sending of the MT page
response message on the current paging channel without adding the
current serving base station or the current paging channel to the
temporary avoidance/forbidden list in response to determining that
the MAPE threshold is exceeded comprises: stopping sending of the
MT page response message on the current paging channel without
adding the current serving base station or the current paging
channel to the temporary avoidance/forbidden list in response to
determining that the MAPE threshold is exceeded and that the base
station handover occurred since the MT paging message was
received.
9. The method of claim 8, further comprising: adding the current
serving base station or the current paging channel to the temporary
avoidance/forbidden list in response to determining that the MAPE
threshold is exceeded and that the base station handover has not
occurred since the MT paging message was received; and stopping
sending of the MT page response message on the current paging
channel in response to adding the current serving base station or
the current paging channel to the temporary avoidance/forbidden
list.
10. The method of claim 7, further comprising: determining whether
a MT call is established; stopping sending of the MT page response
message on the current paging channel in response to determining
that the MT call is established; and re-sending the MT page
response message to the current serving base station on the current
paging channel in response to determining that the MT call is not
established.
11. A communication device, comprising: a single radio frequency
(RF) resource; and a processor coupled to the single RF resource
and configured with processor-executable instructions to: receive
an Mobile Termination (MT) paging message; determine whether a base
station handover has occurred since the MT paging message was
received; determine a current paging channel that the communication
device selected from a current serving base station in response to
determining that the base station handover has occurred since the
MT paging message was received; determine whether there is a
mismatch between the current paging channel and an original paging
channel that the communication device had selected from an original
serving base station when the MT paging message was received; and
send a MT page response message to the current serving base station
on the current paging channel in response to determining the
mismatch between the current paging channel and the original paging
channel.
12. The communication device of claim 11, wherein the processor is
further configured with processor-executable instructions to
determine whether there is the mismatch between the current paging
channel and the original paging channel that the communication
device had selected from the original serving base station when the
MT paging message by determining whether a first Walsh code of the
current paging channel and a second Walsh code of the original
paging channel are the same when the current paging channel and the
original paging channel have a common carrier frequency.
13. The communication device of claim 11, wherein the processor is
further configured with processor-executable instructions to send
the MT page response message to the original serving base station
on the original paging channel in response to determining that the
base station handover has not occurred since the MT paging message
was received.
14. The communication device of claim 11, wherein the processor is
further configured with processor-executable instructions to send
the MT page response message to the current serving base station on
the original paging channel in response to determining that there
is not a mismatch between the current paging channel and the
original paging channel.
15. The communication device of claim 11, wherein the processor is
further configured with processor-executable instructions to:
reconfigure the single RF resource to respond to the MT paging
message; and determine the current serving base station after
reconfiguring the single RF resource.
16. The communication device of claim 11, wherein the processor is
further configured with processor-executable instructions to
determine the original paging channel that the communication device
had selected from the original serving base station when the MT
paging message was received.
17. The communication device of claim 11, wherein the processor is
further configured with processor-executable instructions to:
determine whether a Max Access Probe Exit (MAPE) threshold is
exceeded after sending the MT page response message on the current
paging channel; and stop sending of the MT page response message on
the current paging channel without adding the current serving base
station or current paging channel to a temporary
avoidance/forbidden list in response to determining that the MAPE
threshold is exceeded.
18. The communication device of claim 17, wherein the processor is
further configured with processor-executable instructions to stop
sending of the MT page response message on the current paging
channel without adding the current serving base station or current
paging channel to the temporary avoidance/forbidden list in
response to determining that the MAPE threshold is exceeded by:
stopping sending of the MT page response message on the current
paging channel without adding the current serving base station or
current paging channel to the temporary avoidance/forbidden list in
response to determining that the MAPE threshold is exceeded and
that the base station handover occurred since the MT paging message
was received.
19. The communication device of claim 18, wherein the processor is
further configured with processor-executable instructions to: add
the current serving base station or current paging channel to the
temporary avoidance/forbidden list in response to determining that
the MAPE threshold is exceeded and that the base station handover
has not occurred since the MT paging message was received; and stop
sending of the MT page response message on the current paging
channel in response to adding the current serving base station or
current paging channel to the temporary avoidance/forbidden
list.
20. The communication device of claim 17, wherein the processor is
further configured with processor-executable instructions to:
determine whether a MT call is established; stop sending of the MT
page response message on the current paging channel in response to
determining that the MT call is established; and re-send the MT
page response message to the current serving base station on the
current paging channel in response to determining that the MT call
is not established.
21. A non-transitory processor-readable storage medium having
stored thereon processor-executable instructions configured to
cause a processor of a single radio long term evolution (SRLTE)
communication device to perform operations to manage Mobile
Termination (MT) paging messages, comprising: receiving an MT
paging message; determining whether a base station handover has
occurred since the MT paging message was received; determining a
current paging channel that the SRLTE communication device selected
from a current serving base station in response to determining that
the base station handover has occurred since the MT paging message
was received; determining whether there is a mismatch between the
current paging channel and an original paging channel that the
SRLTE communication device had selected from an original serving
base station when the MT paging message was received; and sending a
MT page response message to the current serving base station on the
current paging channel in response to determining the mismatch
between the current paging channel and the original paging
channel.
22. A single radio long term evolution (SRLTE) communication
device, comprising: means for receiving a Mobile Termination (MT)
paging message; means for determining whether a base station
handover has occurred since the MT paging message was received;
means for determining a current paging channel that the SRLTE
communication device selected from a current serving base station
in response to determining that the base station handover has
occurred since the MT paging message was received; means for
determining whether there is a mismatch between the current paging
channel and an original paging channel that the SRLTE communication
device had selected from an original serving base station when the
MT paging message was received; and means for sending a MT page
response message to the current serving base station on the current
paging channel in response to determining the mismatch between the
current paging channel and the original paging channel.
Description
BACKGROUND
[0001] Mobile communication devices--such as smart phones--may be
single radio long term evolution (SRLTE) communication devices in
which a single radio frequency resource (RF resource) supports both
data and voice calls in a mobile telephony network (e.g., Code
Division Multiple Access (CDMA) networks or Global System for
Mobile Communications (GSM) Enhanced Data Rate for GSM Evolution
(EDGE) Radio Access Network (GERAN) networks).
[0002] When an incoming call is available for an SRLTE
communication device, the mobile telephony network enters a Mobile
Switching Center (MSC)-Sub paging scenario in which the network
attempts to notify the SRLTE communication device of the incoming
call by sending Mobile Termination (MT) paging messages to the
SRLTE communication device on all configured paging channels for
the serving base station (BS) for the SRLTE communication device
registered with the network, as well as through all paging channels
for the base stations neighboring the serving base station. When
the SRLTE communication device receives the MT paging message via
one of the paging channels, the SRLTE communication device responds
with an MT page response message indicating that the MT call can be
established.
[0003] However, the process of responding to a received MT paging
message is not instantaneous. Delays result from processing the MT
paging message and delays in reconfiguring the RF resource of the
SRLTE communication device. For example, when the SRLTE
communication device is conducting a data call at the time a MT
paging message is received, an Extended Service Request (ESR)
procedure for the data service may need to be completed before an
MT page response can be sent by the SRLTE communication device.
[0004] During delays between receiving MT paging messages and being
able to send MT page response messages, the SRLTE communication
device may have handed off from the serving base station to another
new base station due to movement of the device and/or changing
network conditions. The paging channel in the new base station may
be different from the paging channel in the previous serving base
station on which the MT paging message was received. In current
systems, prior to sending an MT page response, the SRLTE
communication device will check the current paging channel being
used against the paging channel on which the MT paging message was
received. In response to determining that there is a mismatch
between the current paging channel and the paging channel on which
the MT paging message was received, the SRLTE communication device
will drop the MT paging message. Dropping the MT paging message
causes the SRLTE communication device to not send a MT page
response and leads to a delay in establishing the call or a
preemptive drop of the call.
SUMMARY
[0005] Various embodiments provide methods, devices, and
non-transitory processor-readable storage media for mitigating the
risk of delayed connection or call failure during base station (BS)
handover by preventing single radio long term evolution (SRLTE)
communication devices from dropping Mobile Termination (MT) paging
messages due to paging channel mismatches (e.g., mismatches between
the Walsh codes used for different paging channels).
[0006] Methods for managing MT paging messages in a SRLTE
communication device according to various embodiments include
receiving an MT paging message, determining whether a base station
handover has occurred since the MT paging message was received,
determining a current paging channel that the SRLTE communication
device selected from a current serving base station in response to
determining that a base station handover has occurred since the MT
paging message was received, determining whether there is a
mismatch between the current paging channel and an original paging
channel that the SRLTE communication device had selected from an
original serving base station when the MT paging message was
received, and sending a MT page response message to the current
serving base station on the current paging channel in response to
determining that there is a mismatch between the current paging
channel and the original paging channel.
[0007] In some embodiments, the methods may further include sending
the MT page response message to the original serving base station
on the original paging channel in response to determining that a
base station handover has not occurred since the MT paging message
was received. In some embodiments, the methods may further include
sending the MT page response message to the current serving base
station on the original paging channel in response to determining
that there is not a mismatch between the current paging channel and
the original paging channel. In some embodiments, the methods may
further include reconfiguring a single radio frequency (RF)
resource to respond to the MT paging message, and determining the
current serving base station after reconfiguring the single RF
resource.
[0008] In some embodiments, the methods may further include
determining the original paging channel that the SRLTE
communication device had selected from the original serving base
station when the MT paging message was received. In some
embodiments, the methods may further include determining whether a
Max Access Probe Exit (MAPE) threshold is exceeded after sending
the MT page response message on the current paging channel, and
stopping sending of the MT page response message on the current
paging channel without adding the current serving base station or
current paging channel to a temporary avoidance/forbidden list in
response to determining that the MAPE threshold is exceeded.
[0009] In some embodiments, the methods may further include
determining whether a MT call is established, stopping sending of
the MT page response message on the current paging channel in
response to determining that a MT call is established, and
re-sending the MT page response message to the current serving base
station on the current paging channel in response to determining
that a MT call is not established.
[0010] In some embodiments determining whether there is a mismatch
between the current paging channel and an original paging channel
that the SRLTE communication device had selected from an original
serving base station when the MT paging message was received may
include determining whether a first Walsh code of the current
paging channel and a second Walsh code of the original paging
channel are the same when the current paging channel and the
original paging channel have a common carrier frequency.
[0011] In some embodiments stopping sending of the MT page response
message on the current paging channel without adding the current
serving base station or current paging channel to a temporary
avoidance/forbidden list in response to determining that the MAPE
threshold is exceeded may include stopping sending of the MT page
response message on the current paging channel without adding the
current serving base station or current paging channel to a
temporary avoidance/forbidden list in response to determining that
the MAPE threshold is exceeded and that a base station handover
occurred since the MT paging message was received. In some
embodiments, the methods may further include adding the current
serving base station or current paging channel to a temporary
avoidance/forbidden list in response to determining that the MAPE
threshold is exceeded and that a base station handover has not
occurred since the MT paging message was received, and stopping
sending of the MT page response message on the current paging
channel in response to adding the current serving base station or
current paging channel to a temporary avoidance/forbidden list.
[0012] Various embodiments may include a communication device, such
as a SRLTE communication device, configured with
processor-executable instructions to perform operations of the
methods described above.
[0013] Various embodiments may include a communication device, such
as a SRLTE communication device, having means for performing
functions of the operations of the methods described above.
[0014] Various embodiments may include non-transitory
processor-readable media on which are stored processor-executable
instructions configured to cause a processor of a communication
device, such as a SRLTE communication device, to perform operations
of the methods described above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The accompanying drawings, which are incorporated herein and
constitute part of this specification, illustrate exemplary
embodiments, and together with the general description given above
and the detailed description given below, serve to explain the
features of the various embodiments.
[0016] FIG. 1 is a communication system block diagram of a network
suitable for use with the various embodiments.
[0017] FIG. 2 is a block diagram illustrating a single radio
long-term evolution (SRLTE) communication device according to
various embodiments.
[0018] FIG. 3 is a block diagram of a Mobile Switching Center
(MSC)-Sub paging scenario according to an embodiment.
[0019] FIG. 4 is a process flow diagram illustrating an embodiment
method for preventing a SRLTE communication device from dropping
Mobile Termination paging messages due to paging channel
mismatches.
[0020] FIG. 5 is a block diagram of an MSC-Sub paging scenario
according to another embodiment.
[0021] FIG. 6 is process flow diagram illustrating an embodiment
method for stopping sending a MT page response message without
adding a current paging channel and/or current serving base station
to a temporary avoidance/forbidden list.
[0022] FIG. 7 is a component block diagram of a communication
device suitable for implementing some embodiment methods.
DETAILED DESCRIPTION
[0023] Various embodiments will be described in detail with
reference to the accompanying drawings. Wherever possible, the same
reference numbers will be used throughout the drawings to refer to
the same or like parts. References made to particular examples and
implementations are for illustrative purposes, and are not intended
to limit the scope of the disclosure or the claims.
[0024] SRLTE communication devices can select a particular paging
channel out of multiple paging channels supported by a BS (base
station) based on its unique International Mobile Subscriber
Identity (IMSI) value. The SRLTE communication device learns about
the paging channels supported on a particular BS via a System
Parameters overhead message. If there are more than one paging
SRLTE specified in the System Parameters Message (i.e.,
PAGE_CHAN>1), the SRLTE communication device will use a hash
algorithm (with HASH KEY based on the device's unique IMSI value)
to select a particular a Paging Channel number in the range [1,
PAGE_CHAN] in order to listen to SRLTE communication device
directed messages from BS. In other words, the SRLTE communication
device may hash onto a paging channel by using a hash key based on
the SRLTE communication device's unique IMSI value in a hash
algorithm to select a particular paging channel number from the
range of supported paging channels to listen for SRLTE
communication device directed messages from the base station. Since
this selection of a particular paging channel involves the use of a
hash function, the selected paging channel may be referred to
herein as the channel onto which the SRLTE communication device is
"hashed."
[0025] Various embodiments mitigate the risk of delayed connection
or call failure during base station (BS) handover by preventing
SRLTE communication devices from dropping Mobile Termination (MT)
paging messages due to paging channel mismatches (e.g., mismatches
between the Walsh codes used for different paging channels). In
various embodiments, when the SRLTE communication device proceeds
to handle/respond to an MT paging message, the SRLTE communication
device may determine whether a base station handover has occurred
since the MT paging message was received. In response to
determining that a base station handover has occurred since the MT
paging message was received, the SRLTE communication device may
determine whether the current paging channel (i.e., the paging
channel that the SRLTE communication device is currently hashed
onto) with the current (i.e., new) serving base station is
different from the paging channel of the original (i.e., previous)
base station on which the MT paging message was received. For
example, in various networks, the same carrier frequency may be
used by all paging channels, and different paging channels may be
created by modulating the carrier frequency with different Walsh
codes to create different channels. In such networks, the SRLTE
communication device may determine whether the current paging
channel (i.e., the paging channel that the SRLTE communication
device is currently hashed onto) with the current (i.e., new)
serving base station is different from the paging channel of the
original (i.e., previous) base station on which the MT paging
message was received by determining whether the Walsh codes used to
modulate the common carrier frequency of the paging channels are
different, and thus the paging channels are effectively
different.
[0026] In response to determining that there is a paging channel
mismatch between the current paging channel (i.e., the paging
channel that the SRLTE communication device is currently hashed
onto) with the current (i.e., new) serving base station and the
paging channel of the original (i.e., previous) base station on
which the MT paging message was received (e.g., the Walsh codes are
different), in various embodiments the SRLTE communication device
may send a MT page response message to the current serving base
station via the current (i.e., new) paging channel (i.e., the
paging channel that the SRLTE communication device is currently
hashed onto with the current serving base station). This MT page
response message may be sent via a new paging channel with the new
Walsh code that the SRLTE communication device is currently hashed
onto with the new serving base station. The current serving base
station will likely have the MT page context, because in the Mobile
Switching Center (MSC)-Sub paging scenario the neighbor base
stations may also send MT paging messages on all their respective
paging channels. Thus, the new serving base station may expect the
MT page response message from the SRLTE communication device and
may handle the response message appropriately. In this manner, the
SRLTE communication device may successfully respond to the MT
paging message even though a base station handover occurred, and
the MT call may be established via the current (i.e., new) serving
base station.
[0027] In various embodiments, in a scenario in which the current
serving base station does not have an MT page context established,
the SRLTE communication device may repeatedly send the MT page
response message via the current paging channel (i.e., the paging
channel that the SRLTE communication device is currently hashed
onto) with the current serving base station without the MT call
being established. The call may not be established because the base
station was not notified by the MSC to attempt to establish the MT
call, not because the base station did not receive the MT page
response message. Thus, the base station will take no action. This
situation may be caused by the SRLTE communication device traveling
to a cell served by a base station that was not a neighbor base
station of the original serving base station when the MSC-Sub
paging scenario occurred. Because the call is not established in
response to repeated MT page response messages sent by the SRLTE
communication device, a Max Access Probe Exit (MAPE) threshold for
sending MT page response messages may be exceeded.
[0028] In current systems, when the MAPE threshold is exceeded, the
SRLTE communication device places the paging channel and/or base
station on the temporary avoidance/forbidden list. In current
systems, this "blacklisting" of the paging channel and/or base
station occurs because the failure to establish the call is assumed
to be due to low quality of service with the serving base
station.
[0029] However, in various embodiments, the failure to establish
the MT call may not be due to a problem with the quality of
service, but because the current (i.e., new) serving base station
was not a paging base station when the MSC-Sub paging scenario
occurred. Thus, in various embodiments, in response to determining
that a base station handover occurred since the MT paging message
was received and a MAPE threshold for sending MT page response
messages is exceeded, the SRLTE communication device may stop
sending the MT page response message without adding the current
paging channel or current serving base station to a temporary
avoidance/forbidden list.
[0030] The term "communication device," is used herein to refer to
any one or all of cellular telephones, smart phones, personal or
mobile multi-media players, personal data assistants (PDAs), laptop
computers, tablet computers, smart books, palm-top computers,
wireless electronic mail receivers, multimedia Internet enabled
cellular telephones, wireless gaming controllers, and similar
personal electronic devices that include a programmable processor
and memory and circuitry for establishing wireless communication
pathways and transmitting/receiving data via wireless communication
pathways. The various aspects may be useful in single radio
long-term evolution (SRLTE) communication devices, such as smart
phones, and so such devices are referred to in the descriptions of
various embodiments. However, the embodiments may be useful in any
electronic devices in which a single radio frequency resource (RF
resource) supports both data and voice calls in a mobile telephony
network, such as Code Division Multiple Access (CDMA) networks or
Global System for Mobile Communications (GSM) Enhanced Data Rate
for GSM Evolution (EDGE) Radio Access Network (GERAN) networks.
[0031] Various embodiments may be implemented within a variety of
communication systems 100, an example of which is illustrated in
FIG. 1. A first mobile network 102 and a second mobile network 104
typically each include a plurality of cellular base stations (e.g.,
a first base station 130 and a second base station 140). The
networks 102, 104 may also be referred to by those of skill in the
art as access networks, radio access networks, base station
subsystems (BSSs), UMTS Terrestrial Radio Access Networks (UTRANs),
etc. The networks 102, 104 may use the same or different wireless
interfaces and/or physical layers. In an embodiment, the base
stations 130, 140 may be controlled by one or more base station
controllers (BSCs). Alternate network configurations may also be
used and the embodiments are not limited to the configuration
illustrated.
[0032] A first SRLTE communication device 110 may be in
communication with the first mobile network 102 through a cellular
connection 132 to the first base station 130. The first SRLTE
communication device 110 may also be in communication with the
second mobile network 104 through a cellular connection 142 to the
second base station 140. The first base station 130 may be in
communication with the first mobile network 102 over a wired
connection 134. The second base station 140 may be in communication
with the second mobile network 104 over a wired connection 144.
[0033] A second SRLTE communication device 120 may similarly
communicate with the first mobile network 102 through the cellular
connection 132 to the first base station 130. The second SRLTE
communication device 120 may communicate with the second mobile
network 104 through the cellular connection 142 to the second base
station 140.
[0034] The cellular connections 132 and 142 may be made through
two-way wireless communication links, such as GSM (particularly,
GERAN), Universal Mobile Telecommunications Systems (UMTS)
(particularly, Long Term Evolution (LTE)), Frequency Division
Multiple Access (FDMA), Time Division Multiple Access (TDMA), CDMA,
Wi-Fi, Personal Communications (PCS), Third Generation (3G), Fourth
Generation (4G), Fifth Generation (5G), or other mobile telephony
communication technologies.
[0035] In various embodiments, the SRLTE communication devices 110,
120 may access networks 102, 104 after camping on cells managed by
the base stations 130, 140. In some embodiments the SRLTE
communication devices 110, 120 may engage in one active
communication at a time, such as a single data call or single voice
call.
[0036] In the system 100, the SRLTE communication devices 110, 120
may be multi-SIM communication devices that are capable of
operating with a number of wireless networks enabled by information
stored in a plurality of SIMs. Using dual-SIM functionality, the
SRLTE communication devices 110, 120 may access the two networks
102, 104 by camping on cells managed by the base stations 130,
140.
[0037] While the SRLTE communication devices 110, 120 are shown
connected to the mobile networks 102, 104, in some embodiments (not
shown), the SRLTE communication devices 110, 120 may include one or
more subscriptions to two or more mobile networks 102, 104 and may
connect to those networks in a manner similar to operations
described above.
[0038] In some embodiments, the first SRLTE communication device
110 may establish a wireless connection 152 with a peripheral
device 150 used in connection with the first SRLTE communication
device 110. For example, the first SRLTE communication device 110
may communicate over a Bluetooth.RTM. link with a Bluetooth-enabled
personal computing device (e.g., a "smart watch"). In some
embodiments, the first SRLTE communication 110 may establish a
wireless connection 162 with a wireless access point 160, such as
over a Wi-Fi connection. The wireless access point 160 may be
configured to connect to the Internet 164 or another network over a
wired connection 166.
[0039] While not illustrated, the second SRLTE communication device
120 may similarly be configured to connect with the peripheral
device 150 and/or the wireless access point 160 over wireless
links.
[0040] The networks 102, 104 may be interconnected by public
switched telephone network (PSTN) 124, across which the networks
102, 104 may route various incoming and outgoing communications to
the SRLTE communication devices 110, 120.
[0041] FIG. 2 is a functional block diagram of an example SRLTE
communication device 200 that is suitable for implementing various
embodiments. With reference to FIGS. 1-2, the SRLTE communication
device 200 may be similar to one or more of the SRLTE communication
devices 110, 120. The SRLTE communication device 200 may include a
first SIM interface 202a, which may receive a first identity module
SIM 204a that is associated with the first subscription. The
wireless device 200 may also include a second SIM interface 202b,
which may receive a second identity module SIM 204b that is
associated with the second subscription.
[0042] A SIM in various embodiments may be a Universal Integrated
Circuit Card (UICC) that is configured with SIM and/or USIM
applications, enabling access to, for example, GSM and/or UMTS
networks. The UICC may also provide storage for a phone book and
other applications. Alternatively, in a CDMA network, a SIM may be
a UICC removable user identity module (R-UIM) or a CDMA subscriber
identity module (CSIM) on a card. Each SIM card may have a CPU,
ROM, RAM, EEPROM, and I/O circuits.
[0043] A SIM used in various embodiments may contain user account
information, an international mobile subscriber identity (IMSI), a
set of SIM application toolkit (SAT) commands, and storage space
for phone book contacts. A SIM card may further store home
identifiers (e.g., a System Identification Number (SID)/Network
Identification Number (NID) pair, a Home PLMN (HPLMN) code, etc.)
to indicate the SIM card network operator provider. An Integrated
Circuit Card Identity (ICCID) SIM serial number is printed on the
SIM card for identification. However, a SIM may be implemented
within a portion of memory of the SRLTE communication device 200
(e.g., memory 214), and thus need not be a separate or removable
circuit, chip or card.
[0044] The SRLTE communication device 200 may include at least one
controller, such as a general processor 206, which may be coupled
to a coder/decoder (CODEC) 208. The CODEC 208 may in turn be
coupled to a speaker 210 and a microphone 212. The general
processor 206 may also be coupled to the memory 214. The memory 214
may be a non-transitory computer readable storage medium that
stores processor-executable instructions. For example, the
instructions may include routing communication data relating to the
first or second subscription though a corresponding baseband-RF
resource chain.
[0045] The memory 214 may store an operating system (OS), as well
as user application software and executable instructions. The
memory 214 may also store application data, such as an array data
structure.
[0046] The general purpose processor 206 and the memory 214 may
each be coupled to at least one baseband modem processor 216. Each
SIM 204a, 204b in the SRLTE communication device 200 may share a
baseband-RF resource chain. A baseband-RF resource chain may
include the baseband modem processor 216, which may perform
baseband/modem functions for communicating with/controlling a RAT,
and may include one or more amplifiers and radios, referred to
generally herein as RF resources (e.g., RF resources 218). The RF
resource 218 may be coupled to antenna 220, and may perform
transmit/receive functions for the wireless services associated
with each SIM 204a, 204b of the SRLTE communication device 200. The
RF resource 218 may provide separate transmit and receive
functionality, or may include a transceiver that combines
transmitter and receiver functions.
[0047] In some embodiments, the general processor 206, the memory
214, the baseband processor(s) 216, and the RF resources 218a, 218b
may be included in the SRLTE communication device 200 as a
system-on-chip. In some embodiments, the first and second SIMs
204a, 204b and their corresponding interfaces 202a, 202b may be
external to the system-on-chip. Further, various input and output
devices may be coupled to components on the system-on-chip, such as
interfaces or controllers. Example user input components suitable
for use in the SRLTE communication device 200 may include, but are
not limited to, a keypad 224, a touchscreen display 226, and the
microphone 212.
[0048] In some embodiments, the keypad 224, the touchscreen display
226, the microphone 212, or a combination thereof, may perform the
function of receiving a request to initiate an outgoing call. For
example, the touchscreen display 226 may receive a selection of a
contact from a contact list or receive a telephone number. In
another example, either or both of the touchscreen display 226 and
the microphone 212 may perform the function of receiving a request
to initiate an outgoing call. For example, the touchscreen display
226 may receive a selection of a contact from a contact list or to
receive a telephone number. As another example, the request to
initiate the outgoing call may be in the form of a voice command
received via the microphone 212. Interfaces may be provided between
the various software modules and functions in the SRLTE
communication device 200 to enable communication between them.
[0049] FIG. 3 is a block diagram of a MSC-Sub paging scenario
according to various embodiments in which the SRLTE communication
device 200 travels from a first cell 302 to a second cell 304
before responding to a MT paging message. With reference to FIGS.
1-3, at a first time, the SRLTE communication device 200 may be
located within the first cell 302 managed by a base station (BS) A.
The base station A may be configured to operate with a paging
channel X, and the SRLTE communication device 200 may camp on the
base station A by selecting the paging channel X from the base
station A to listen for MT paging messages addressed to the SRLTE
communication device 200. For example, the SRLTE communication
device 200 may determine the number of paging channels supported by
the base station A (e.g., paging channel X) from an overhead
message, such as a System Parameters overhead message. The SRLTE
communication device 200 may select the paging channel X from the
base station A by using a hash key based on the SRLTE communication
device's 200 unique IMSI value in a hash algorithm, thereby hashing
onto the paging channel X with the base station A to listen for MT
paging messages addressed to the SRLTE communication device 200.
The second cell 304 managed by the base station B may be a neighbor
cell to the first cell 302, and the base station B may be
configured to operate with a paging channel Y. The paging channels
X and Y may use different Walsh codes. For example, a common paging
channel signal may be modulated (e.g., spread) using a first Walsh
code to generate the paging channel X transmitted by the base
station A and a second different Walsh code to generate the paging
channel Y transmitted by the base station B.
[0050] When a MT call is available for the SRLTE communication
device 200, the MSC-Sub paging scenario may be initiated in the
network and the MSC may direct the serving base station A for the
SRLTE communication device 200, as well as any neighbor base
stations (e.g., base station B), to send MT paging messages on all
of their respective paging channels in an attempt to notify the
SRLTE communication device 200 of the incoming MT call. In this
manner, the serving base station A and any of its neighbor base
stations (e.g., base station B) may become paging base stations and
may establish a MT page context for the SRLTE communication device
200 to listen for MT page response messages from the SRLTE
communication device 200.
[0051] While the SRLTE communication device 200 may receive the MT
paging message in the first cell 302, there may be a delay in
responding to the MT paging message at the SRLTE communication
device 200. Delays may result from processing the MT paging message
and from reconfiguring the RF resource 218 of the SRLTE
communication device 200. For example, when the SRLTE communication
device 200 is conducting a data call at the time that a MT paging
message is received, an Extended Service Request (ESR) procedure
for the data service may need to be completed before an MT page
response message can be sent by the SRLTE communication device
200.
[0052] During the delay in responding to the MT paging message, the
SRLTE communication device 200 may travel to the second cell 304
and may select the paging channel Y from the base station B. For
example, the SRLTE communication device 200 may determine the
number of paging channels supported by the base station B (e.g.,
paging channel Y) from an overhead message, such as a System
Parameters overhead message. The SRLTE communication device 200 may
select the paging channel Y from the base station B by using a hash
key based on the SRLTE communication device's 200 unique IMSI value
in a hash algorithm, thereby hashing onto the paging channel Y with
the base station B. In this manner, the base station A may be
considered the original serving base station for the SRLTE
communication device 200 and the paging channel X may be the
original paging channel for the SRLTE communication device 200,
while the base station B and the paging channel Y may be considered
the current serving base station and current paging channel,
respectively, for the SRLTE communication device 200. In various
embodiments, the SRLTE communication device 200 may determine that
there is a paging channel mismatch between the paging channel X and
the paging channel Y (e.g., the Walsh codes for paging channel X
and Y are different), but may send a MT page response message on
the paging channel Y to the base station B despite the mismatch.
The base station B may receive the MT page response of the paging
channel Y and may expect the MT page response from the SRLTE
communication device 200 because the base station B has the MT page
context for the SRLTE communication device 200. The MT call may
then be successfully established with the SRLTE communication
device 200 via the base station B in the cell 304.
[0053] FIG. 4 illustrates a method 400 for preventing a SRLTE
communication device from dropping MT paging messages due to paging
channel mismatches according to various embodiments. With reference
to FIGS. 1-4, the method 400 may be implemented with a processor
(e.g., the general processor 206, the baseband modem processor 216,
a separate controller, and/or the like) of a SRLTE communication
device (e.g., the SRLTE communication device 200). In block 402,
the processor may begin performing operations of the method 400 by
listening for one or more MT paging messages. In various
embodiments, the SRLTE communication device may have selected a
paging channel of a base station (e.g., by hashing onto the paging
channel of the base station) and may listen for paging messages,
such as a MT paging message on the paging channel.
[0054] In determination block 404, the processor may determine
whether an MT paging message is received. In response to
determining that a MT paging message is not received (i.e.,
determination block 404="No"), the processor may continue to listen
for MT paging messages in block 402.
[0055] In response to determining that a MT paging message is
received (i.e., determination block 404="Yes"), the processor may
determine the original serving base station and original paging
channel that the SRLTE communication device selected (hashed onto)
and on which the MT paging message is received in block 406. As
described above, the original serving base station and original
paging channel may be the paging channel of the serving base
station when the MT paging message is received. As an example, the
SRLTE communication device may have selected the original paging
channel from the serving base station by using a hash key based on
the SRLTE communication device's unique IMSI value in a hash
algorithm, thereby hashing onto the original paging channel.
[0056] In block 408, the processor may process the MT paging
message and reconfigure the RF resource to respond to the MT paging
message. For example, when the SRLTE communication device is
conducting a data call at the time a MT paging message is received,
processing the MT paging message and reconfiguring the RF resource
to respond to the MT paging message may include performing an ESR
procedure for the data service.
[0057] In block 410, the processor may determine the current
serving base station. In various embodiments, determining the
current serving base station may be performed upon completion of
the operations of block 408 to process the MT paging message and
reconfigure the RF resource to respond to the MT paging message. In
this manner, the processor may identify the current serving base
station after any delay caused by processing the MT paging message
and reconfiguring the RF resource to respond to the MT paging
message has occurred.
[0058] In determination block 412, the processor may determine
whether a base station handover has occurred since the MT paging
message was received (in block 404). The processor may determine
that a base station handover has occurred since the MT paging
message was received by comparing the base station identifier of
the original serving base station to the base station identifier of
the determined current serving base station. In response to
determining that a base station handover has not occurred (i.e.,
determination block 412="No"), the processor may send the MT page
response message to the original serving base station on the
original paging channel in block 414. The processor may then
continue to listen for MT paging messages on the original paging
channel in block 402.
[0059] In response to determining that a base station handover has
occurred (i.e., determination block 412="Yes"), the processor may
determine the current paging channel selected by the SRLTE
communication device in block 416. As an example, the processor may
determine the current paging channel selected by the SRLTE
communication device by determining the paging channel from the
serving base station onto which the SRLTE communication device is
hashed. The processor may determine the paging channel onto which
the SRLTE communication device is hashed by determining a channel
identifier and/or Walsh code used for the current paging channel
used by the current serving base station.
[0060] In determination block 418, the processor may determine
whether there is a paging channel mismatch between the original
paging channel and the current paging channel. For example, the
processor may determine whether the Walsh codes of the channels are
different.
[0061] In response to determining that the paging channels are the
same (i.e., determination block 418="No"), the processor may send
the MT page response message to the current serving base station on
the original paging channel in block 420. The processor may then
continue to listen for MT paging messages on the original paging
channel in block 402.
[0062] In response to determining that there is a channel mismatch
(i.e., determination block 418="Yes"), the processor may send the
MT page response message to the current serving base station on the
current paging channel in block 420. In this manner, the processor
may send the MT page response to the current serving base station
on a paging channel different from the paging channel on which the
MT paging message was originally received, such as on a paging
channel with different Walsh codes. The processor may then continue
to listen for MT paging messages on the current paging channel in
block 402.
[0063] FIG. 5 is a block diagram of an MSC-Sub paging scenario
according to various embodiments in which the SRLTE communication
device 200 travels from the first cell 302 to a third cell 502
before responding to a MT paging message. With reference to FIGS.
1-5, at a first time, the SRLTE communication device 200 may be
located within the first cell 302 managed by a base station A as
described. In this example, rather than traveling to the second
cell 304 that is a neighbor cell to cell 302 before responding to
the MT paging message, the SRLTE communication device has traveled
to a third cell 502 managed by a base station C that is not a
neighbor cell to the first cell 302. The base station C may be
configured to operate with a paging channel Y, which as described
may be different from the paging channel X. Thus, during the delay
in responding to the MT paging message, the SRLTE communication
device 200 may select the paging channel Y from the base station C.
For example, the SRLTE communication device 200 may determine the
number of paging channels supported by the base station C (e.g.,
paging channel Y) from an overhead message, such as a System
Parameters overhead message. The SRLTE communication device 200 may
select the paging channel Y from the base station C by using a hash
key based on the SRLTE communication device's 200 unique IMSI value
in a hash algorithm, thereby hashing onto the paging channel Y with
the base station C.
[0064] Because the third cell 502 is not a neighbor cell to the
first cell 302, in the MSC-Sub paging scenario, the base station C
may not generate a MT page context and may not expect a MT page
response message from the SRLTE communication device 200. Thus,
even though the SRLTE communication device 200 may send the MT page
response message to the base station C, the base station C may not
acknowledge the MT page response message or establish the MT call
with the SRLTE communication device 200. The failure to establish
the MT call after sending the MT page response message one or more
times may cause the SRLTE communication device 200 to exceed the
MAPE threshold. In various embodiments, in response to determining
that the MAPE threshold is exceeded, the SRLTE communication device
200 may determine whether a base station handover occurred since
the MT paging message was received. In response to determining that
a base station handover did occur since the MT paging message was
received, the SRLTE communication device 200 may stop sending the
MT page response message to the base station C without adding the
base station C or the paging channel Y to the temporary
avoidance/forbidden list. In this manner, even though the MT call
establishment failed between the base station C and the SRLTE
communication device 200, the base station C and the paging channel
Y may still be used by the SRLTE communication device 200.
[0065] FIG. 6 illustrates a method according to various embodiments
for stopping the sending of a MT page response message without
adding a current paging channel and/or current serving base station
to a temporary avoidance/forbidden list according to various
embodiments. With reference to FIGS. 1-6, the method 600 may be
implemented with a processor (e.g., the general processor 206, the
baseband modem processor 216, a separate controller, and/or the
like) on a SRLTE communication device (e.g., the SRLTE
communication device 200).
[0066] In various embodiments, the operations of method 600 may be
performed in conjunction with the operations of the method 400 as
described, such as after the operations of blocks 414, 420, and 422
or before the operations of block 402 of the method 400. In
response to sending an MT page response message in blocks 414, 420,
or 422, the processor of the device may increment a MAPE counter in
block 602. A MAPE counter may be a counter that tracks the number
of sent MT page response messages that may be incremented after
each transmission of a MT page response message by the SRLTE
communication device.
[0067] In block 604, the processor may determine whether a MT call
is established. For example, the processor may determine whether a
base station acknowledged the sent MT page response message and/or
a traffic channel with the base station is established for a MT
call. In response to determining that a MT call is established
(i.e., determination block 604="Yes"), the processor may stop
sending the MT page response message in block 612 and reset the
MAPE counter in block 614. The processor may then continue to
listen for MT paging messages in block 402 of the method 400.
[0068] In response to determining that a MT call is not established
(i.e., determination block 604="No"), the processor may resend the
MT page response message in block 606. The processor may resend the
MT page response message on the same paging channel and to the same
base station as the MT page response message was sent in blocks
414, 420, or 422 of the method 400, respectively. In this manner,
the processor may reattempt to establish the MT call.
[0069] In determination block 608, the processor may determine
whether a MAPE threshold is exceeded. The MAPE threshold may be a
set maximum threshold for sending MT page response messages. The
processor may compare a value of the MAPE counter to the MAPE
threshold to determine whether the number of sent MT page response
messages exceeds the MAPE threshold. In response to determining
that the MAPE threshold is not exceeded (i.e., determination block
608="No"), the processor may increment the MAPE counter in block
602.
[0070] In response to determining that the MAPE threshold is
exceeded (i.e., determination block 608="Yes"), the processor may
determine whether a base station handover occurred since the MT
paging message was received in block 412 of the method 400.
Conducting a base station handover since the MT paging message was
received may be the reason that the MT call was not established
when the serving base station did not have a MT page context
established because the serving base station was not a neighbor
cell when the MT page message was sent. Thus, when a base station
handover has occurred since the MT paging message was received, the
failure to establish the MT call may be unrelated to the quality of
service with the serving base station. In contrast, when a base
station handover has not occurred, the failure to establish the MT
call is more likely due to low quality of service with the serving
base station.
[0071] In response to determining that a base station handover has
not occurred (i.e., determination block 608="No"), the processor
may add the serving base station and/or paging channel to a
temporary avoidance/forbidden list in block 610. In this manner,
the processor may "blacklist" base stations and/or paging channels
likely experiencing a low level of quality of service. Upon adding
the serving base station and/or paging channel to a temporary
avoidance/forbidden list, the processor may stop sending the MT
page response message in block 612 and reset the MAPE counter in
block 614. The processor may then continue to listen for MT paging
messages in block 402 of the method 400.
[0072] In response to determining that a base station handover has
occurred (i.e., determination block 608="Yes"), the processor may
stop sending the MT page response message in block 612 without
adding the serving base station and/or paging channel to a
temporary avoidance/forbidden list. The processor may reset the
MAPE counter in block 614. The processor may then continue to
listen for MT paging messages in block 402 of the method 400.
[0073] Various embodiments may be implemented in any of a variety
of communication devices, an example on which (e.g., SRLTE
communication device 700) is illustrated in FIG. 7. With reference
to FIGS. 1-7, the SRLTE communication device 700 may be similar to
the SRLTE communication devices 110, 120, 200 and may implement the
methods 400 and/or 600 as described.
[0074] The SRLTE communication device 700 may include a processor
702 coupled to a touchscreen controller 704 and an internal memory
706. The processor 702 may be one or more multi-core integrated
circuits designated for general or specific processing tasks. The
internal memory 706 may be volatile or non-volatile memory, and may
also be secure and/or encrypted memory, or unsecure and/or
unencrypted memory, or any combination thereof. The touchscreen
controller 704 and the processor 702 may also be coupled to a
touchscreen panel 712, such as a resistive-sensing touchscreen,
capacitive-sensing touchscreen, infrared sensing touchscreen, etc.
Additionally, the display of the SRLTE communication device 700
need not have touch screen capability.
[0075] The SRLTE communication device 700 may have one or more
cellular network transceivers 708, 716 coupled to the processor 702
and to two or more antennae 710, 711 and configured for sending and
receiving cellular communications. The transceivers 708, 716 and
the antennae 710, 711 may be used with the above-mentioned
circuitry to implement the various embodiment methods. The SRLTE
communication device 700 may include one or more SIM cards (e.g.,
SIM 713) coupled to the transceivers 708, 716 and/or the processor
702 and configured as described. The SRLTE communication device 700
may include a cellular network wireless modem chip 717 that enables
communication via a cellular network and is coupled to the
processor 702.
[0076] The SRLTE communication device 700 may also include speakers
714 for providing audio outputs. The SRLTE communication device 700
may also include a housing 720, constructed of a plastic, metal, or
a combination of materials, for containing all or some of the
components discussed herein. The SRLTE communication device 700 may
include a power source 722 coupled to the processor 702, such as a
disposable or rechargeable battery. The rechargeable battery may
also be coupled to the peripheral device connection port to receive
a charging current from a source external to the SRLTE
communication device 700. The SRLTE communication device 700 may
also include a physical button 724 for receiving user inputs. The
SRLTE communication device 700 may also include a power button 726
for turning the SRLTE communication device 700 on and off.
[0077] The foregoing method descriptions and the process flow
diagrams are provided merely as illustrative examples and are not
intended to require or imply that the operations of various
embodiments must be performed in the order presented. As will be
appreciated by one of skill in the art the order of operations in
the foregoing embodiments may be performed in any order. Words such
as "thereafter," "then," "next," etc. are not intended to limit the
order of the operations; these words are simply used to guide the
reader through the description of the methods. Further, any
reference to claim elements in the singular, for example, using the
articles "a," "an" or "the" is not to be construed as limiting the
element to the singular.
[0078] The various illustrative logical blocks, modules, circuits,
and algorithm operations described in connection with the
embodiments disclosed herein may be implemented as electronic
hardware, computer software, or combinations of both. To clearly
illustrate this interchangeability of hardware and software,
various illustrative components, blocks, modules, circuits, and
operations have been described above generally in terms of their
functionality. Whether such functionality is implemented as
hardware or software depends upon the particular application and
design constraints imposed on the overall system. Skilled artisans
may implement the described functionality in varying ways for each
particular application, but such implementation decisions should
not be interpreted as causing a departure from the scope of the
various embodiments.
[0079] The hardware used to implement the various illustrative
logics, logical blocks, modules, and circuits described in
connection with the aspects disclosed herein may be implemented or
performed with a general purpose processor, a digital signal
processor (DSP), an application specific integrated circuit (ASIC),
a field programmable gate array (FPGA) or other programmable logic
device, discrete gate or transistor logic, discrete hardware
components, or any combination thereof designed to perform the
functions described herein. A general-purpose processor may be a
microprocessor, but, in the alternative, the processor may be any
conventional processor, controller, microcontroller, or state
machine A processor may also be implemented as a combination of
computing devices, e.g., a combination of a DSP and a
microprocessor, a plurality of microprocessors, one or more
microprocessors in conjunction with a DSP core, or any other such
configuration. Alternatively, some operations or methods may be
performed by circuitry that is specific to a given function.
[0080] In one or more exemplary aspects, the functions described
may be implemented in hardware, software, firmware, or any
combination thereof. If implemented in software, the functions may
be stored as one or more instructions or code on a non-transitory
computer-readable storage medium or non-transitory
processor-readable storage medium. The operations of a method or
algorithm disclosed herein may be embodied in a
processor-executable software module, which may reside on a
non-transitory computer-readable or processor-readable storage
medium. Non-transitory computer-readable or processor-readable
storage media may be any storage media that may be accessed by a
computer or a processor. By way of example but not limitation, such
non-transitory computer-readable or processor-readable storage
media may include RAM, ROM, EEPROM, FLASH memory, CD-ROM or other
optical disk storage, magnetic disk storage or other magnetic
storage devices, or any other medium that may be used to store
desired program code in the form of instructions or data structures
and that may be accessed by a computer. Disk and disc, as used
herein, includes compact disc (CD), laser disc, optical disc,
digital versatile disc (DVD), floppy disk, and blu-ray disc where
disks usually reproduce data magnetically, while discs reproduce
data optically with lasers. Combinations of the above are also
included within the scope of non-transitory computer-readable and
processor-readable media. Additionally, the operations of a method
or algorithm may reside as one or any combination or set of codes
and/or instructions on a non-transitory processor-readable storage
medium and/or computer-readable storage medium, which may be
incorporated into a computer program product.
[0081] The preceding description of the disclosed embodiments is
provided to enable any person skilled in the art to make or use the
various embodiments. Various modifications to these embodiments
will be readily apparent to those skilled in the art, and the
generic principles defined herein may be applied to some
embodiments without departing from the spirit or scope of the
various embodiments. Thus, the various embodiments are not intended
to be limited to the examples shown herein but are to be accorded
the widest scope consistent with the following claims and the
principles and novel features disclosed herein.
* * * * *