Note: Descriptions are shown in the official language in which they were submitted.
CA 02565225 2006-10-23
METHOD AND APPARATUS FOR TRANSITIONING BETWEEN EVDO AND CDMA
IX SYSTEMS USING REDUNDANT DATA CALL BLOCKINGS
FIELD OF THE APPLICATION
The present application relates to the optimization of a data device in a CDMA
1 X/EVDO mobile system, and in particular to the reduction or elimination of
unnecessary
network calls from the hybrid access terminal.
BACKGROUND
A CDMA 1 X/EVDO hybrid access terminal (mobile device) is a hybrid system that
has evolved from the CDMA 2000 system. EVDO standards for Evolution Data Only
or
Data Optimized and, as suggested by this, is a data only system.
Alternatively, EVDO is
also known as High Rate Packet Data (HRPD). One advantage of EVDO systems is
that
they allow a higher transfer rate for data. They are also useful to carriers
to clear the 1X
system for more voice capacity by removing data traffic from the 1 X system.
The 1 X
system is also known in the art as 3G1X.
A hybrid access terminal operating in a 1 X/EVDO hybrid mode will first
acquire the
CDMA 1X system and once this system has been acquired and the hybrid access
terminal is in an idle stage, it will try to acquire an EVDO system. The CDMA
1X system
will always have precedence over the EVDO system according to current design
specification in terms of initial system acquisition. Once the Ix system is
acquired, a
hybrid access terminal starts periodic monitoring for the availability of any
EV-DO systems
as EVDO system is more preferred for packet data service and the fact that
EVDO system
also provides the capability to receive an incoming voice call even during
active packet
data session which is not possible on lx system.
On transition from a CDMA 1X system to an EVDO system, or vice versa, a hybrid
access terminal with a dormant packet data session initiates a data call to
the new
system. This is required so that the device connects the current data session
with the
new system upon transition as the wireless network may need to move the data
context
information associated with the hybrid access terminal from source to target
network.
This is also known as packet data "reconnect" process. This occurs when the
device
transitions from the EVDO system to the 1X system, or vice versa.
If for any reason the transition between and EVDO system and a 1 X system
fails, a
problem exists with redundant data calls being made. For example, a problem
exists in
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CA 02565225 2006-10-23
boundary areas where the EVDO system may be seen by the hybrid access terminal
and
the terminal attempts to make a transition due to preference of EVDO system
over lx
system. During such transition attempts, EVDO system may not be able to be
acquired, or
may be acquired and quickly dropped due to signal strength variations or the
hybrid
access terminal moving into and out of the boundary area. The problem with
this is that a
data call is made if the hybrid access terminal fails to transition to the
EVDO system and
moves back to a 1X system. Since the network considers the device in the 1X
system
already, this data call is redundant and wastes mobile battery life and
network resources.
SUMMARY
The present method and apparatus overcome the deficiencies of the prior art by
preventing a redundant data call. Three solUtions are presented herein and the
solutions
can be used individually or in combination with each other. Further, a method
for
optimizing battery life can be used in combination with any of the above
solutions, alone
or in combination with each other.
The first solution is to block the redundant data call. This is done if an
unsuccessful attempt is made to connect to an EVDO or a 1X system and the
hybrid
access terminal moves back to its previous system. In this case, the hybrid
access
terminal can check whether or not the new system was acquired successfully and
if not,
the data call can be blocked in this case.
Alternatively, transition criteria can be set which prevents connection to an
EVDO
system unless the threshold is exceeded. Alternatively, other criteria could
be used to
reduce the probability of unsuccessful connection. These criteria can include
EVDO
signal strength should exceed a threshold for a certain time duration. Other
criteria are
possible. For example, the radio sensitivity of the hybrid access terminal
could be the
threshold, and the EVDO received signal strength indication must be greater
than or
equal to the receiver sensitivity.
A third solution is to monitor the radio frequency environment and connect
only
when the radio frequency environment is conducive to the connection. This last
solution
varies the timer used for connection to the EVDO system, and the timer will
only expire
when the environment is conducive to the connection to the EVDO system.
Fast dormancy can be used with any of the above to save the battery life of
the
hybrid access terminal when connecting to an EVDO system or a 1X system. Fast
dormancy allows a hybrid access terminal to release the packet data call in
situation when
it can determine that it is done with data exchange, but wireless network can
not. By doing
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CA 02565225 2006-10-23
so, it can enter packet data dormant state faster and save battery life that
would have
been wasted by unnecessarily keeping the data call longer than required.
The above solutions can be used alone, or in combination with one another. For
example, the transition criteria can be used as a first check, and an attempt
to connect to
the EVDO system can then be confirmed to be successful prior to sending out a
data call.
In this case, if the connection to the EVDO system is not successful then the
data call
can be blocked. Similarly, other solutions and combinations will be evident to
those
skilled in the art based on the teachings herein.
The present application therefore provides a method of optimizing
transitioning
between EVDO and CDMA 1X systems in a hybrid access terminal comprising the
steps
of: detecting a transition between CDMA 1 X and EVDO; checking whether the
transition
between the CDMA 1X and EVDO system is successful; and if not blocking a
reconnect
data call from the hybrid access terminal.
The present application further provides a method of optimizing transitioning
between EVDO and CDMA 1X systems in a hybrid access terminal comprising the
steps
of: detecting an EVDO received signal at the hybrid access terminal; checking
whether a
signal strength indication of the EVDO received signal is greater than or
equal to a
threshold for a predetermined duration; and if yes allowing the hybrid access
terminal to
connect to the EVDO system.
The present application still further provides a method of optimizing
transitioning
between EVDO and CDMA 1X systems in a hybrid access terminal comprising the
steps
of: detecting an EVDO received signal at the hybrid access terminal; and
delaying a
connection timer at the hybrid access terminal for connecting to the EVDO
system.
The present application still further provides a hybrid access terminal
adapted for
optimizing transitioning between EVDO and CDMA 1X systems, the hybrid access
terminal having a radio subsystem adapted to communicate with a network; a
radio
processor having a digital signal processor and adapted to interact with said
radio
subsystem; memory; a user interface; a processor adapted to run user
applications and
interact with the memory, the radio and the user interface and adapted to run
applications,
the hybrid access terminal characterized by having means for: detecting a
transition
between CDMA 1 X and EVDO; checking whether the transition between the CDMA 1
X
and EVDO system is successful; and if not blocking a reconnect data call from
the hybrid
access terminal.
The present application still further provides a hybrid access terminal
adapted for
optimizing transitioning between EVDO and CDMA 1X systems, the hybrid access
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CA 02565225 2006-10-23
terminal having a radio subsystem adapted to communicate with a network; a
radio
processor having a digital signal processor and adapted to interact with said
radio
subsystem; memory; a user interface; a processor adapted to run user
applications and
interact with the memory, the radio and the user interface and adapted to run
applications,
the hybrid access terminal characterized by having means for: detecting an
EVDO
received signal at the hybrid access terminal; checking whether a signal
strength
indication of the EVDO received signal is greater than or equal to a threshold
for a
predetermined duration; and if yes allowing the hybrid access terminal to
connect to the
EVDO system.
The present appiication yet further provides a hybrid access terminal adapted
for
optimizing transitioning between EVDO and CDMA 1X systems, the hybrid access
terminal having a radio subsystem adapted to communicate with a network; a
radio
processor having a digital signal processor and adapted to interact with said
radio
subsystem; memory; a user interface; a processor adapted to run user
applications and
interact with the memory, the radio and the user interface and adapted to run
applications,
the hybrid access terminal characterized by having means for: detecting an
EVDO
received signal at the hybrid access terminal; and delaying a connection timer
at the
hybrid access terminal for connecting to the EVDO system.
BRIEF DESCRIPTION OF THE DRAWINGS
The present method and apparatus will be better understood with reference to
the
drawings in which:
Figure 1 is a flow chart of a method of avoiding redundant data calls
according to
one aspect of the present application;
Figure 2 is a flow chart of a method according to an aspect of the present
application in which one of multiple 1X networks can be acquired;
Figure 3 is a flow chart of a method to avoid acquiring an EVDO system if
certain
preconditions are not met;
Figure 4 is a flow chart of method to improve battery life on a hybrid access
terminal that has transitioned to an EVDO state;
Figure 5 is a flow chart of method to improve battery life on a hybrid access
terminal that has lost an EVDO state;
Figure 6 is a flow chart of an alternative method for avoiding connecting to
an
EVDO system unless certain preconditions are met;
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CA 02565225 2006-10-23
Figure 7 is a flow chart of a further alternative method for avoiding
connecting to
an EVDO system unless certain preconditions are met;
Figure 8 is a flow chart showing a combination of the methods of Figure 1 and
Figure 3;
Figure 9 is a flow chart showing a combination of the methods of Figures 1, 3
and
4;
Figure 10 is a flow chart showing a combination of the methods of Figure 7 and
4;
Figure 11 is flow chart showing a combination of the methods of Figures 3 and
6;
Figure 12 is a flow chart showing a combination of the methods of Figures 1,
3,4
and 6;
Figure 13 shows an exemplary network in which the above methods can be
implemented; and
Figure 14 is an exemplary hybrid access terminal that can be used in
accordance
with the present methods.
DETAILED DESCRIPTIONS
As will be appreciated by those skilled in the art, when a hybrid access
terminal is
on a boundary between networks, it can "ping pong" between these networks and
needs
to reacquire these systems continuously. This is both draining on battery life
of the hybrid
access terminal and can cause network resources to be used unnecessarily.
If the hybrid access terminal supports voice and packet data service, it
operates in
a CDMA 1X/EVDO hybrid system. In this system, the hybrid access terminal first
acquires
the CDMA 1 X system, after which it tries to acquire an EVDO system. EVDO
systems are
preferable to the user of the hybrid access terminal since they have a higher
data rate,
and also to carriers since moving the data calls off of the CDMA 1 X system
frees up voice
capacity on the 1X system. In addition, EVDO system also provides the
capability to
receive an incoming voice call even during active packet data session, which
is not
possible on 1 x system.
As indicated above, when a hybrid access terminal is in an area close to a
boundary for an EVDO system, the hybrid access terminal may continuously try
to acquire
the EVDO system because of its preference over lx system. If the attempt to
acquire the
EVDO system is unsuccessful, the hybrid access terminal will move back into
the 1X
system. The problem with this is that devices typically are required to
initiate a data call to
reconnect its existing packet data session when they move between systems to
tell the
CA 02565225 2006-10-23
new system that the hybrid access terminal has transferred between either the
1X to the
EVDO or from the EVDO to the 1X. However, in the event of an unsuccessful
attempt,
the device will typically move back to its former 1X state and not be required
to reacquire
the 1X system. Prior art systems have still made a redundant data call in this
situation.
The sending of redundant data calls causes the battery to be drained more
quickly
on the hybrid access terminal and further causes network congestion. Also,
while the
device is sending a data call it is unable to receive voice traffic. Thus for
a period when
the hybrid access terminal moves to EVDO state unsuccessfully and then back
into the
1 X state it sends a data call with a dormancy period after the data call.
During this data
call and the dormancy period a voice call is unable to be sent to the hybrid
access
terminal and is automatically rerouted to the voice mail system.
The present application presents the solution of preventing the redundant data
call. This can be done in various ways, and three solutions that can be used
individually
or in combination with each other are presented below.
Blocking the Redundant Data Call
Reference is now made to Figure 1. If a hybrid access terminal in a dormant 1X
state 10 detects an EVDO signal, the hybrid access terminal proceeds to step
12 in which
it tries to acquire the EVDO system. As will be appreciated by those skilled
in the art, it is
preferable that the data device handle its data calls in the EVDO system, thus
freeing up
the 1X system for increased voice capacity. Further, the EVDO system provides
higher
bandwidth, which is preferable for the hybrid access terminal. Prior to
transitioning, the
hybrid access terminal should store the system identifier/network
identifier/packet zone
identifier (SID/NID/PZID) of the 1X system.
From step 12, the hybrid access terminal proceeds to step 14 in which it
checks
whether or not the EVDO system was successfully acquired. This could be if a
successful
point to point protocol (PPP) session is established with the new system. If
the EVDO
system was not successfully acquired the hybrid access terminal proceeds to
step 18 in
which the hybrid access terminal periodically searches for an EVDO system.
Conversely, if the EVDO acquire in step 12 was successful, the hybrid access
terminal proceeds to step 22 in which it tries to move the data session to
EVDO. If
successful in step 22, the hybrid access terminal proceeds to step 16 and the
process is
ended.
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If the hybrid access terminal is unsuccessful in step 22, the hybrid access
terminal
next proceeds to step 20 in which a redundant call is blocked. As will be
appreciated by
those skilled in the art, the redundant data call results from the hybrid
access terminal
moving from an EVDO state into a 1X state. In this case, since the EVDO state
was only
moved to in a failed attempt to acquire the EVDO system, the transitioning
back to the 1X
state does not require a data call, since the network currently thinks that
the hybrid access
terminal is accessing data over the 1X system. The method of Figure 1 realizes
that the
data call in this case is redundant and thus in step 20 blocks it.
The hybrid access terminal next proceeds to step 16 in which the process is
ended.
Reference is now made to Figure 2. Like reference numerals are used for
similar
steps to those in Figure 1.
In some cases, the 1 X system that is acquired if the EVDO attempt is
unsuccessful
may be different from the 1X system that was previously acquired.
Specifically, in areas
that are serviced by multiple networks or in boundary areas, a different 1X
system may be
acquired upon failure to acquire an EVDO system. In this case, a hysteresis
table can be
used to track recently accessed 1X systems and data calls can be blocked if
the 1X
system was recently acquired.
Referring to Figure 2, the hybrid access terminal is in a 1X state and in step
12
tries to acquire to an EVDO system. In step 14 the hybrid access terminal
checks
whether or not the acquisition was successful and if it was, moves to step 22
where the it
tries to move the data session.
Conversely, if the hybrid access terminal is unsuccessful in step 14 it
proceeds to
step 24 in which it periodically checks for an EVDO system.
If the data session transition in step 22 was unsuccessful, the hybrid access
terminal proceeds to step 26. In step 26 the hybrid access terminal checks
whether the
1 X system exists in the hysteresis table. The hysteresis table will store
systems that have
been acquired within a predetermined time period from the current time. If the
hybrid
access terminal had accessed the 1 X system within that time period, the data
call will be
redundant and thus the hybrid access terminal proceeds to step 20 in which the
data call
is blocked in 1X.
Conversely, the hybrid access terminal proceeds to step 28 from step 26 if the
hysteresis table does not contain the 1X system. In step 28 the data call is
allowed. As
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CA 02565225 2006-10-23
will be appreciated by those skilled in the art, step 28 can only be accessed
if the
hysteresis table does not find the 1X system acquired in step 24.
The hybrid access terminal next proceeds to step 16 in which the method is
ended.
As will be appreciated, the SID/NID/PZID of the currently connected network
can
be used to check for successful acquiring of an EVDO data session. In one
embodiment,
the SID/NID/PZID should only be replaced in memory by the color code/Sector ID
of the
EVDO system once the PPP session is established successfully.
The above therefore illustrates various embodiments of a method for blocking
redundant data calls in transitions between IX and EVDO when the hybrid access
terminal
fails to acquire one of the EVDO systems.
Sinnal Threshold
As an alternative to, or in addition to, the blocking of redundant calls, a
further
alternative according to the present apparatus and method is to ensure that an
EVDO
system is not acquired unless the received signal strength of EVDO system
exceeds a
predetermined threshold. As an alternative, the hybrid access terminal can
also use its
own receiver sensitivity as a threshold for received signal strength of EVDO
system.
Reference is now made to Figure 3. A hybrid access terminal is a dormant 1X
state 10 and in step 50 acquires EVDO. The hybrid access terminal proceeds to
step 52
in which it checks the EVDO received signal strength indication (RSSI) to see
whether this
is greater than a receiver sensitivity on the hybrid access terminal. If the
EVDO RSSI is
greater than or equal to the receiver sensitivity, then the hybrid access
terminal proceeds
to step 54 in which the EVDO data session can be moved to. Conversely, if in
step 52 it
is determined that the EVDO/RSSI is less than the receiver sensitivity, the
hybrid access
terminal proceeds to step 56 in which it will keep the data session in its 1X
state.
From step 54 or step 56, the hybrid access terminal proceeds to step 16 in
which
the process is ended.
As will be appreciated from the above, the sending of redundant data calls is
prevented in the above case by ensuring that the EVDO signal is greater than a
certain
threshold in order to ensure that the EVDO system can be successfully acquired
the first
time.
Check RF Environment
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CA 02565225 2006-10-23
A further alternative is to monitor the radio frequency environment of the
device to
intelligently decide when to try to acquire an EVDO system.
Reference is made to Figure 6. Figure 6 shows a method for addressing a
situation where the forward link is good but an Access attempt is failing due
to a bad
reverse link. As per the method of Figure 6, a hybrid access terminal
exponentially backs
off trying to acquire the 'particular' EVDO System (that EVDO channel). During
that
AVOID period, the hybrid access terminal can try to acquire other EVDO
Systems.
Anytime the hybrid access terminal is able to successfully acquire and access
any
other EVDO system, the AVOID time of the above is reset. Further, anytime an
access
attempt is successful in the system the hybrid access terminal was avoiding,
the avoid
time will be reset to zero.
Referring to Figure 6, the hybrid access terminal in step 70 checks acquires a
first
EVDO system, labelled herein as EVDOj. The hybrid access terminal proceeds to
step
72 in which a count is set to zero and step 74 in which the count is
incremented.
The hybrid access terminal proceeds from step 74 to step 78 in which an access
attempt is made. In step 79 the hybrid access terminal checks whether the
access failed.
If not, the hybrid access terminal proceeds to step 16 and the process ends.
If the access is found to have failed in step 79, the mobile device proceeds
to step
82 in which an avoid time is set. In the example of Figure 6, the avoid time
is set by
multiplying a constant times the count. As will be appreciated, a maximum
value for this
can also be set.
In one embodiment, the constant can be set to a predetermined duration, such
as
60 seconds. Thus for the first attempt the time is set to 60 seconds, for the
second
attempt the time is set to 120 seconds, and so on to the maximum time allowed.
From step 82 the hybrid access terminal proceeds to step 80 in which it checks
whether the avoid timer has expired. If not, the hybrid access terminal
proceeds to step
84 where it checks whether there are any other EVDO systems (EVDO,,) it can
acquire
and set a data session to.
In step 84, if the hybrid access terminal finds an EVDO system to connect to,
it
resets the count and avoid times for EVDO, in step 86. Otherwise step 84 loops
back to
step 80.
From step 80, if the avoid timer has expired the hybrid access terminal
proceeds to
step 88 and tries to acquire EVDOj. The hybrid access terminal next proceeds
back to
step 74 and increments the counter.
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An optional step with the above is to reduce or reset the EVDO reconnect delay
if
the system lost count is less than the maximum allowed. This is not shown in
Figure 6.
Referring to Figure 7, the method depicted therein addresses two issues: 1) if
the
forward link is bad in the acquired EVDO System or 2) EVDO coverage is spotty-
i.e.
sometimes a hybrid access terminal is successfully able to move a data session
to EVDO
but loses the EVDO system frequently during traffic session or even after
being in idle in
EVDO. The method of Figure 7, upon the first time an EVDO system is acquired,
starts a
timer and a System Lost count. Upon expiry of the timer, the System loss count
is
checked to see if a'Max System Loss Count' is reached. If the max did not
reached, it the
decision is made that current RF situation of the EVDO System is not as bad as
predicted
or previously observed, and therefore the timer and the System loss count is
reset to zero.
On the other hand, if the System loss count is found to have reached the max
System loss count within the monitoring period, then another parameter 'EVDO
Data
Reconnect Delay' is increased. In any subsequent occasion, if this EVDO System
was
acquired, before trying to move data session to this EVDO system, the hybrid
access
terminal will wait for the above delay before trying to reconnect. This 'EVDO
Data
reconnect Delay' is also exponentially increased as device keeps on staying in
similar
EVDO RF condition.
Reference is now made to Figure 7. The hybrid access terminal starts in a
dormant 1X state 10. The hybrid access terminal proceeds to step 100 in which
it
attempts to acquire an EVDO system, labelled herein as EVDOI. The hybrid
access
terminal next proceeds to step 102 in which it checks whether the EVDO system
is the
same system as previously acquired.
If not, the hybrid access terminal proceeds to step 104 in which the EVDO
System
Lost Count N is set to 0 and step 106 in which Monitor Timer T is started.
From step 106 the hybrid access terminal proceeds to step 108 in which a check
is
made to see if the EVDO system is lost. Alternatively, step 108 can also be
accessed
from step 102 if the same system has previously been acquired.
If the hybrid access terminal finds in step that the EVDO system has not been
lost
the hybrid access terminal proceeds to step 110 in which it checks whether the
data
session is in EVDO. If not the hybrid access terminal proceeds to step 112 and
the data
session is moved. If yes, or from step 112, the hybrid access terminal
proceeds back to
step 108.
CA 02565225 2006-10-23
If the hybrid access terminal finds that the EVDO system was lost in step 108,
it
proceeds to step 114 in which the loss count is incremented. The hybrid access
terminal
next proceeds to step 116 in which it checks whether the monitor timer is
greater than a
maximum monitor timer. If it is, then the hybrid access terminal proceeds to
check how
many system losses occurred during the timer period. In step 118 if the system
loss
count is greater than a maximum allowed, the EVDO reconnect delay is increased
incrementally, up to a maximum value in step 120. Further, the system loss
count is reset
in step 122 to start again.
If in step 116 the monitor timer is less than a maximum, or if in step 118 the
loss
count is less than the maximum allowed, the hybrid access terminal proceeds to
step 124
in which it checks whether the data session is already in 1X. It will be
appreciated that
this check avoids redundant data calls from being made.
If in step 124 a data session is not in 1X the hybrid access terminal proceeds
to
step 126 to move the data session into 1X. Subsequently the hybrid access
terminal
proceeds to a dormant 1X state 10. Step 124 can also proceed directly to
dormant 1X
state 10 if the data session is already in 1X.
The above therefore ensures that the environment is in a state that is
conducive to
a successful EVDO connection.
Fast Dormancy
Reference is now made to Figure 4. In traditional systems, when transitioning
to
an EVDO system, the data call terminating will cause the EVDO to move to a
dormant
state. This usually is done according to a preset time value, for example, 20
seconds.
Fast dormancy causes the EVDO system to move into its dormant state more
quickly.
The battery life of the hybrid access terminal is improved by moving into a
dormant state
more quickly since the data channel does not need to be kept active. An
optimal timer
value for moving into a dormant state can be set based on statistical
analysis.
As will be appreciated, the method of Figure 4 does not reduce redundant calls
but it saves the battery life on the hybrid access terminal.
Referring to Figure 4, a hybrid access terminal is a dormant 1X state 10 and
in
step 60 it transitions to EVDO. In step 61 the hybrid access terminal moves
the data
session to EVDO.
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Once the transition occurs and the data call is ended the hybrid access
terminal
proceeds to step 62 in which fast dormancy is applied. Thus the hybrid access
terminal
moves more quickly into its dormant state in step 62.
The hybrid access terminal next moves to step 16 in which the process ends.
Referring to Figure 5, a hybrid access terminal is a dormant EVDO state 65 and
in
step 66 loses EVDO. In step 66 the hybrid access terminal moves the data
session to
1 X.
Once the transition occurs and the data call is ended the hybrid access
terminal
proceeds to step 62 in which fast dormancy is applied. Thus the hybrid access
terminal
moves more quickly into its dormant state in step 62.
The hybrid access terminal next moves to step 16 in which the process ends.
The above four solutions therefore provide for better battery life on the
hybrid
access terminal and in most cases above, also provide for the blocking of
redundant data
calls to the network from the hybrid access terminal, thus also saving network
resources.
As will be appreciated, the above four solutions can be used individually or,
in one
preferred embodiment, two or more of the above four ways of saving battery
life and
reducing redundant calls can be combined.
Reference is now made to Figure 8. Figure 8 shows a combination of the signal
threshold method and the redundant call blocking method. Specifically, a
hybrid access
terminal is in dormant 1 X state 10 and detects an EVDO signal in and acquires
the EVDO
system in step 50.
In step 52 the hybrid access terminal checks whether the EVDO RSSI is greater
than or equal to the receiver sensitivity and if not the hybrid access
terminal proceeds to
step 56 in which it keeps the data session in 1X and then ends in step 16.
Conversely, if the EVDO RSSI is greater than or equal to the receiver
sensitivity,
the hybrid access terminal can proceed to step 22 in which it attempts to move
the data
session to EVDO. The hybrid access terminal then proceeds to step 20 in which
it blocks
the redundant data call. From step 22 if the data session move to EVDO attempt
is
successful or from step 20 the hybrid access terminal next proceeds to step 16
in which
the process is ended.
Referring to Figure 9, Figure 9 illustrates a combination of the call
blocking, signal
threshold and fast dormancy methods. Specifically, a hybrid access terminal is
in state 10
and in step 50 detects an EVDO signal and acquires the EVDO system. In step 52
it
checks to see whether the EVDO RSSI is greater than or equal to the receiver
sensitivity
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and if no, the hybrid access terminal proceeds to step 56 in which the data
session stays
in the 1 X system. The hybrid access terminal proceeds to step 16 in which the
process is
ended.
Conversely, if the threshold is greater than or equal to the receiver
sensitivity then
the hybrid access terminal proceeds to step 22 in which it attempts move the
data session
to the EVDO system and checks if this was successful.
If the data session was successfully moved to EVDO, the hybrid access terminal
can apply fast dormancy in step 62 and the process in step 16.
Conversely, if the data session move to EVDO was not successful, then the
hybrid
access terminal can proceed to step 20 in which the data call is blocked. The
hybrid
access terminal then proceeds to step 16 in which the process is ended.
Reference is now made to Figure 10. Figure 10 shows a combination of the call
blocking method, the fast dormancy method and the radio frequency environment
checking method. Specifically, Figure 10 is identical to the method of Figure
7 with the
exception that from step 112 if the data session is moved to EVDO, the hybrid
access
terminal proceeds to step 62 in which fast dormancy is applied and then to
step 108 in
which a check is made to see if the system is lost.
Reference is now made to Figure 11. Figure 11 shows the combination of the
radio frequency environment method and the threshold method. In this case, the
hybrid
access terminal is in state 10 and in step 100 detects that there is an EVDO
signal. In
step 52 the hybrid access terminal checks to see whether the EVDO RSSI is
greater than
or equal to the receiver sensitivity. If yes, the hybrid access terminal
proceeds to step 102
in which checks whether the same system is being acquired. The method proceeds
according to the method of Figure 7 after this.
Conversely, if the check in step 52 does not find that the EVDO RSSI is
greater
than or equal to the receiver sensitivity, the hybrid access terminal proceeds
to a dormant
1 X state 10.
Reference is now made to Figure 12. As will be appreciated, all three of the
above solutions, along with the fast dormancy, can be combined. This is
identical to
Figures 11 with the exception that once the hybrid access terminal moves the
data
session to EVDO in step 112, it next proceeds to step 62 in which fast
dormancy is
applied.
Various other combinations of the above four methods could also be used and
the
above is not meant to limit the above to any particular combinations.
13
CA 02565225 2006-10-23
Reference is now made to Figure 13. Figure 13 is a block diagram of an
exemplary wireless data network in accordance with the present application and
with
which the various embodiments of the method of the instant application may
cooperate.
Figure 13 shows a block diagram of a wireless data device 310 and exempiary
CDMA lx
network 320, an exemplary EVDO network 330, a public switched telephone
network
(PSTN) 335, a data network 340, wireless gateway 342 and e-mail server 344
with which
the instant techniques of this application may cooperate. The wireless data
device 310 is
preferably a two-way communication device having data and voice communication
capabilities.
CDMA network 320 is comprised of a base transceiver station (BTS) 322 and a
base station controller (BSC) 324. Base station controller 324 communicates
with a
mobile switching centre 326 which as will be appreciated, is a circuit
switched only
component communicating with PSTN 335. Base station controller 324 further
communicates with a packet data serving node (PDSN) 328 which is a packet
switched
only component. PDSN 328 further communicates with IP network 340.
EVDO network 330 contains an EVDO sector 332, which communicates with
access node (AN) 334. Since the EVDO network 330 is a data only network,
access node
334 communicates only with PDSN 328 and not with any circuit switch
components.
An authentication, authorization and accounting node 336 is associated with AN
334, and a similar node 329 is associated with PDSN 328.
Operationally, hybrid access terminal 310 communicates wirelessly with CDMA
network 320 using BTS 322 and BSC 324 to gain access to the CDMA lx network.
As
indicated above, the CDMA lx network is given priority and the establishment
of the
CDMA network occurs prior to any EVDO network connection being established.
Hybrid access terminal 310 sends and receives both data and voice services
through CDMA network 320 until an EVDO network connection with established.
Base
station controller 324 communicates with circuit switch services provided by
MSC 326
such as voice and short message service (SMS) via PSTN 335.
Prior to an EVDO connection being established, hybrid access terminal 310
further
communicates wirelessly with BTS 322 and BSC 324 to gain access to packet data
services provided by PDSN 328, such as e-mail, wireless application protocol
(WAP) and
other data services via data network 340. Such services are provided through
wireless
gateway 342 and servers such as e-mail server 344.
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CA 02565225 2006-10-23
Once a network connection is established with CDMA lx network 320 and the
hybrid access terminal enters CDMA lx idle state, wireless device 310
establishes a
connection with EVDO network 330. This is done through EVDO sector 332 and AN
334.
In this way, hybrid access terminal 310 gains access to packet data services
provided by
PDSN 328 using EVDO network 330. Subsequent to the establishment of an EVDO
network connection with hybrid access terminal 310, CDMA network 320 is used
to
provide circuit switched services such as voice and SMS while EVDO network 330
is used
to provide packet data services such as e-mail and WAP.
As will be appreciated by those skilled in the art, wireless device 310 can
include
voice communication means such as a headpiece 352 or a user can communicate
directly
into the wireless device 310.
A further advantage of the present system is that due to high transfer rates
associated with EVDO networks, wireless device 310 can be used as a wireless
modem
and be connected through various means such as a USB or other serial port, or
by short
range wireless communications with a computer 354. Computer 354 can then gain
access
to data network 340 through EVDO network 330 using hybrid access terminal 310
as the
modem.
Reference is now made to Figure 14. Figure 14 is a block diagram illustrating
a
hybrid access terminal apt to be used with preferred embodiments of the
apparatus and
method of the present application. Hybrid access terminal 400 is preferably a
two-way
wireless communication device having at least voice and data communication
capabilities.
Hybrid access terminal 400 preferably has the capability to communicate with
other
computer systems on the Internet. Depending on the exact functionality
provided, the
wireless device may be referred to as a data messaging device, a two-way
pager, a
wireless e-mail device, a cellular telephone with data messaging capabilities,
a wireless
Internet appliance, or a data communication device, as examples.
Where hybrid access terminal 400 is enabled for two-way communication, it will
incorporate a communication subsystem 411, including both a receiver 412 and a
transmitter 414, as well as associated components such as one or more,
preferably
embedded or internal, antenna elements 416 and 418, local oscillators (LOs)
413, and a
processing module such as a digital signal processor (DSP) 420. As will be
apparent to
those skilled in the field of communications, the particular design of the
communication
subsystem 411 will be dependent upon the communication network in which the
device is
intended to operate. For example, hybrid access terminal 400 may include a
CA 02565225 2006-10-23
communication subsystem 411 designed to operate within the CDMA 1x/EVDO hybrid
system.
Network access requirements will also vary depending upon the type of network
419. In some CDMA networks network access is associated with a subscriber or
user of
hybrid access terminal 400. A CDMA hybrid access terminal may require a
removable
user identity module (RUIM) or a subscriber identity module (SIM) card in
order to operate
on a CDMA network. . The SIM/RUIM interface 444 is normally similar to a card-
slot into
which a SIM/RUIM card can be inserted and ejected like a diskette or PCMCIA
card. The
SIM/RUIM card can have approximately 64K of memory and hold many key
configuration
451, and other information 453 such as identification, and subscriber related
information.
When required network registration or activation procedures have been
completed, hybrid access terminal 400 may send and receive communication
signals over
the network 419. As illustrated in Figure 13, network 419 can consist of
multiple base
stations communicating with the hybrid access terminal. For example, in a CDMA
lx
EVDO system, a CDMA base station and an EVDO base station communicate with the
hybrid access terminal and the hybrid access terminal is connected to both
simultaneously. The EVDO and CDMA lx base stations use different paging slots
to
communicate with the hybrid access terminal.
Signals received by antenna 416 through communication network 419 are input to
receiver 412, which may perform such common receiver functions as signal
amplification,
frequency down conversion, filtering, channel selection and the like, and in
the example
system shown in Figure 14, 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 the DSP 420. In a similar manner, signals to be
transmitted
are processed, including modulation and encoding for example, by DSP 420 and
input to
transmitter 414 for digital to analog conversion, frequency up conversion,
filtering,
amplification and transmission over the communication network 419 via antenna
418.
DSP 420 not only processes communication signals, but also provides for
receiver and
transmitter control. For example, the gains applied to communication signals
in receiver
412 and transmitter 414 may be adaptively controlled through automatic gain
control
algorithms implemented in DSP 420.
Hybrid access terminal 400 preferably includes a microprocessor 438, which
controls the overall operation of the device. Communication functions,
including at least
data and voice communications, are performed through communication subsystem
411.
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CA 02565225 2006-10-23
Microprocessor 438 also interacts with further device subsystems such as the
display
422, flash memory 424, random access memory (RAM) 426, auxiliary input/output
(I/O)
subsystems 428, serial port 430, a keyboard or keypad (or multiple keyboards
or
keypads) 432, speaker 434, microphone 436, other communication subsystem 440
such
as a short-range communications subsystem and any other device subsystems
generally
designated as 442. Serial port 430 could include a USB port or other port
known to those
in the art.
Some of the subsystems shown in Figure 14 perform communication-related
functions, whereas other subsystems may provide "resident" or on-device
functions.
Notably, some subsystems, such as keyboard 432 and display 422, 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 the microprocessor 438 is preferably stored
in
a persistent store such as flash memory 424, which may instead 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 memory such as RAM 426. Received communication signals
may
also be stored in RAM 426.
As shown, flash memory 424 can be segregated into different areas for both
computer programs 458 and program data storage 450, 452, 454 and 456. These
different storage types indicate that each program can allocate a portion of
flash memory
424 for their own data storage requirements. Microprocessor 438, in addition
to its
operating system functions, preferably enables execution of software
applications on the
hybrid access terminal. These functions include executing the solutions
presented above.
A predetermined set of applications that control basic operations, including
at least data
and voice communication applications for example, will normally be installed
on hybrid
access terminal 400 during manufacturing. A preferred software application may
be a
personal information manager (PIM) application having the ability to organize
and
manage data items relating to the user of the hybrid access terminal such as,
but not
limited to, e-mail, calendar events, voice mails, appointments, and task
items. Naturally,
one or more memory stores would be available on the hybrid access terminal to
facilitate
storage of PIM data items. Such PIM application would preferably have the
ability to send
and receive data items, via the wireless network 419. In a preferred
embodiment, the PIM
17
CA 02565225 2006-10-23
data items are seamiessly integrated, synchronized and updated, via the
wireless network
419, with the hybrid access terminal user's corresponding data items stored or
associated
with a host computer system. Further applications may also be loaded onto the
hybrid
access terminal 400 through the network 419, an auxiliary I/O subsystem 428,
serial port
430, short-range communications subsystem 440 or any other suitable subsystem
442,
and installed by a user in the RAM 426 or preferably a non-volatile store (not
shown) for
execution by the microprocessor 438. Such flexibility in application
installation increases
the functionality of the device 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 the hybrid access terminal 400.
In a data communication mode, a received signal such as a text message or web
page download will be processed by the communication subsystem 411 and input
to the
microprocessor 438, which preferably further processes the received signal for
output to
the display 422, or alternatively to an auxiliary I/O device 428. A user of
hybrid access
terminal 400 may also compose data items such as email messages for example,
using
the keyboard 432, which is preferably a complete alphanumeric keyboard or
telephone-
type keypad, in conjunction with the display 422 and possibly an auxiliary I/O
device 428.
Such composed items may then be transmitted over a communication network
through
the communication subsystem 411.
For voice communications, overall operation of hybrid access terminal 400 is
similar, except that received signals would preferably be output to a speaker
434 and
signals for transmission would be generated by a microphone 436. Alternative
voice or
audio I/O subsystems, such as a voice message recording subsystem, may also be
implemented on hybrid access terminal 400. Although voice or audio signal
output is
preferably accomplished primarily through the speaker 434, display 422 may
also be used
to provide an indication of the identity of a calling party, the duration of a
voice call, or
other voice call related information for example.
Serial port 430 in Figure 14, would normally be implemented in a personal
digital
assistant (PDA)-type hybrid access terminal for which synchronization with a
user's
desktop computer (not shown) may be desirable, but is an optional device
component.
Such a port 430 would enable a user to set preferences through an external
device or
software application and would extend the capabilities of hybrid access
terminal 400 by
providing for information or software downloads to hybrid access terminal 400
other than
18
CA 02565225 2006-10-23
through a wireless communication network. The alternate download path may for
example be used to load an encryption key onto the device through a direct and
thus
reliable and trusted connection to thereby enable secure device communication.
As will
be appreciated by those skilled in the art, serial port 430 can further be
used to connect
the hybrid access terminal to a computer to act as a modem. A modem unit 460
interacts
with a driver 462 in a computer 464 to allow data transfer through the hybrid
access
terminal. With EVDO networks, a high rate of data transfer can be achieved
using the
hybrid access terminal 400 as the modem. Depending on the interface provided
by driver
462, unit 460 could be an IP routing module. Further, driver 462 could provide
either a
modem interface or alternatively an IP interface to computer 464. As will be
appreciated
by those skilled in the art, the combination of driver 462 and unit 460 must
provide a
communication interface for computer 430 to be enabled for communications
originated
and/or terminated at computer 430.
Other communications subsystems 440, such as a short-range communications
subsystem, is a further optional component which may provide for communication
between hybrid access terminal 400 and different systems or devices, which
need not
necessarily be similar devices. For example, the subsystem 440 may include an
infrared
device and associated circuits and components or a BluetoothT'" communication
module
to provide for communication with similarly enabled systems and devices.
Advantageously, communications originating and/or terminating at computer 464
benefit from the techniques of this application as module 460 preferably uses
the
techniques taught herein in a manner that is transparent to computer 464.
The embodiments described herein are examples of structures, systems or
methods having elements corresponding to elements of the techniques of this
application.
This written description may enable those skilled in the art to make and use
embodiments
having alternative elements that likewise correspond to the elements of the
techniques of
this application. The intended scope of the techniques of this application
thus includes
other structures, systems or methods that do not differ from the techniques of
this
application as described herein, and further includes other structures,
systems or
methods with insubstantial differences from the techniques of this application
as
described herein.
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